Report 68-04-0020
BRAKE EMISSIONS:  EMISSION MEASUREMENTS
FROM BRAKE AND CLUTCH LININGS
FROM SELECTED MOBILE SOURCES
M. G. Jacko
R. T. DuCharme

Bendix Research Laboratories
Bendix Center
Southfield, Mich.  48076
March 1973
Final Report for Period May 1971 - March 1973
Prepared for
ENVIRONMENTAL PROTECTION AGENCY
Office of Air and Water Programs
Ann Arbor,  Mich. 48105

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BRAKE EMISSIONS:  EMISSION MEASUREMENTS
FROM BRAKE AND CLUTCH LININGS
FROM SELECTED MOBILE SOURCES
M. G. Jacko
R. T. DuCharme

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                                FOREWORD
      The work described herein, "Emissions Measurements from Powered
Brake and Clutch Linings From Selected Mobile Sources," was performed
for the Office of Air and Water Programs, Environmental Protection
Agency, Ann Arbor, Michigan.  This work was carried out under EPA Con-
tract 68-04-0020 from May 10, 1971 to March 31, 1973.  The EPA Project
Technical Officer was Dr. Joseph H. Somers.
      The program was contracted to Bendix Research Laboratories,
Southfield, Michigan.  The work was performed in the Materials and Pro-
cesses Department, Dr. William M. Spurgeon, Manager, of the Mechanical
Sciences and Controls Laboratory, Mr. L. B. Taplin, Director.  The program
was under the supervision of the Principal Investigator, Dr. Michael G.
Jacko.

      Sections 4, 5, and 6 of this report were prepared by Mr. R. T.
DuCharme.  The data base of Section 10 was prepared by Mr.  A. R. Spencer.
All other portions were prepared by Dr. Michael G.  Jacko.

      Other contributors to the program were as follows:  Mr. R. D.
Stapleton (sample collection, sample processing, calculations, and numer-
ous other tasks); Dr. R. M. Rusnak and Mr. D. G. Jones (microscopy analy-
ses); Mr. L. Smith (vehicle test driving); Mr. H. M. Danbert (vehicle
preparation and test driving); Mr. P. R. Stewart (fabrication of collec-
tors); Mr. T. N. Vinson (technical writer); Mr. J.  Gulvezan, Mr. A. Tomala,
and Mr. W. R. Kee of Machine Systems Department (rotating seals designs),
and Mr. C. Cowan and Mr. C. Morton of Bendix Automotive Controls Systems
Group (information on vehicle testing and friction materials).  Computer
programming and processing of computer data were performed by Miss J.
Lindsay.  Mr. C. L. Gray and Mr. W. H. Houtman of EPA are acknowledged
for their suggestions incorporated into the brake emissions collectors.

      Special thanks go to Dr. W. M. Spurgeon, Manager of the Materials
and Processes Department, for his encouragement and suggestions through-
out the program.
ii

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                                ABSTRACT
      In order to define the extent of gas and particulate emissions  from
automotive brakes (and clutches), a combination separation and storage
collection system was devised.  Unique emissions collectors for both  disc
and drum brakes and for a clutch were conceived, designed, and built  as
the main embodiment of this instrumentation.  The hardware was installed
on a vehicle which was then driven through various test cycles to deter-
mine the extent and type of brake emissions generated at low and high
operating temperatures.  Typical driving conditions, such as the Detroit
Traffic Test, as well as more abusive driving conditions such as fade
tests, were included.
      Typical original equipment and aftermarket friction materials for
both disc and drum brakes were used in the tests.   Brake relines were
made to simulate typical consumer-type practices.   The brake emissions
generated were removed from the various collectors and mass balances
were performed.  The particulates were processed and analyzed by a com-
bination of optical and electron microscopy to ascertain the asbestos
content and the asbestos particle size distribution in the wear debris.
Comparisons  of emissions from new and used friction materials, disc  and
drum brakes, and original equipment and aftermarket materials were made.
Finally, an estimate was made of the total emission of asbestos by all
of the vehicles in the country:  on the average, more than 99.7 percent
of the asbestos is converted; the contribution to the atmosphere is 5060
pounds, or 3.2 percent of the total asbestos emissions.
                                                                     iii

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                            TABLE OF CONTENTS
                                                                    Page

 SECTION 1  -  INTRODUCTION AND BRIEF SUMMARY                          1~1

 SECTION 2  -  OBJECTIVES AND  BACKGROUND                               2~1

 2.1    Objectives                                                    2~1
       2.1.1    Objectives of this Program                            2~1
       2.1.2    Bendix  Technical Approach                             2~1
               2.1.2.1  Select Suitable Vehicle and Friction
                        Materials                                   2~1
               2.1.2.2  Conceive, Design, and Build Brake
                        and Clutch Emissions Collectors             2-1
               2.1.2.3  Test a Typical Collector and  Instrument
                        the. Vehicle                                 2-1
               2.1.2.4  Select and Run Suitable Driving Test
                        Schedules
              2.1.2.5   Collect and Analyze Emissions                2-2
              2.1.2.6   Estimate Asbestos Emissions for Cars
                        and Trucks                                  2-2
2.2   Prior Work                                                    2~2

      2.2.1   Published Data                                        2~2
      2.2.2   Unpublished  Data                                       2~3

2.3   Background                                                    2~3
      2.3.1   Energy Absorption by Friction Materials                2-3

              2.3.1.1   Brakes                                       2~3
              2.3.1.2   Clutches                                     2~3

      2.3.2   Compositions of  Friction Materials                     2~4

              2.3.2.1   Generalized Classifications                 2~4
              2.3.2.2   Asbestos                                     2-4
              2.3.2.3   Resin  Binders                                2-5
              2.3.2.4   Property Modifiers                           2-5

                        2.3.2.4.1   Non-Abrasive Modifiers            2-8
                        2.3.2.4.2   Abrasive Modifiers               2-8

      2.3.3   Friction Material Reactions                             2-8

              2.3.3.1   Absorption and Conversion  of Energy          2-8
              2.3.3.2   Physical  and  Chemical  Changes  in
                        Linings During Use                           2-9

      2.3.4   Brake Lining Wear Mechanisms and  Generation
              of Emissions                                            2—13

              2.3.4.1   Types of  Wear  Mechanisms                      2-13
                                                                       v

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                                                                 Page













2.4
2.3.4.1.1 Thermal Wear
2.3.4.1.2 Abrasive Wear
2.3.4.1.3 Adhesive Wear
2.3.4.1.4 Fatigue Wear
2.3.4.1.5 Macroshear Wear
2.3.4.2 Predominant Wear Mechanisms
2.3.4.3 Wear Equation
2.3.5 Emissions of Particulate and Gaseous Emissions
2.3.5.1 Drum Brakes
2.3.5.2 Disc Brakes
2.3.5.3 Clutches
2.3.6 Distribution and Changes in Brake and Clutch
Emissions
References
SECTION 3 - MATERIALS SELECTIONS
3.1
3.2


Background
Materials Selections for Program
3.2.1 Friction Material Selections
3.2.2 Contents of the Friction Materials
SECTION 4 - VEHICLE AND INSTRUMENTATION
4.1
4.2
Vehicle Description
Brake Test Instrumentation
SECTION 5 - EMISSIONS COLLECTION SYSTEMS
5.1


5.2



5.3


5.4


Operation Requirements
5.1.1 Operation and Design Criteria
5.1.2 Emission Expected
Overall Design Concept
5.2.1 Air Flow of a Typical Collection System
5.2.2 Collection Systems Used
5.2.3 Electrical System
Particulate Filters
5.3.1 Filter Holders
5.3.2 Filter Flow Characteristics
Gas Collection Systems
5.4.1 Design and Fabrication of Traps
5.4.2 Operation
2-13
2-16
2-16
2-19
2-19
2-21
2-21
2-23
2-23
2-23
2-24

2-24
2-25
3-1
3-1
3-1
3-1
3-3
4-1
4-1
4-2
5-1
5-1
5-1
5-2
5-2
5-2
5-5
5-5
5-5
5-5
5-9
5-9
5-9
5-14
vi

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                                                                   Page

5.5   Disc Brake Collector                                          5-14

      5.5.1   Shroud Design and Construction                        5-14
      5.5.2   Rotating Seal                                         5-14

              5.5.2.1   Initial Design and Problems                 5-14
              5.5.2.2   Final Design                                5-22

      5.5.3   Thermal Control Aids                                  5-22

5.6   Drum Brake Collector                                          5-27

      5.6.1   Initial Designs and Rotating-Seal Problems            5-27
      5.6.2   Final Design                                          5-31

5.7   Clutch Collector                                              5-31

SECTION 6 - INERTIA DYNAMOMETER TESTING OF THE DISC-BRAKE
            COLLECTOR SYSTEM                                        6-1
6.1   Objectives                                                    6-1

      6.1.1   Demonstration of Collection System Operation          6-1
      6.1.2   Thermal Response                                      6-1
      6.1.3   Rotating Seal Durability                              6-1

6.2   Dynamometer Test Results                                      6-1

      6.2.1   Sealing Practices for Disc Brake Collector            6-1
      6.2.2   Thermal Response Results                              6-2
      6.2.3   Rotating Seal Operation                               6-2
      6.2.4   Emission Collections                                  6-7
      6.2.5   System Integrity                                      6-10

SECTION 7 - VEHICLE TEST SCHEDULES                                  7-1

7.1   Rationale                                                     7-1

      7.1.1   Brakes                                                7-1
      7.1.2   Clutches                                              7-1

7.2   Typical Test Cycles                                           7-1

      7.2.1   Burnish                                               7-1
      7.2.2   Baseline                                              7-2
      7.2.3   Detroit Traffic Test                                  7-2
      7.2.4   10-Stop Fade and Recovery                             7-4
      7.2.5   15-Stop Fade and Recovery                             7-4
      7.2.6   Reburnish                                             7-4

7.3   Selected Vehicle Driving Schedule                             7-5

      7.3.1   Burnish                                               7-5
      7.3.2   After-Burnish (A.B.) Baseline                         7-5
      7.3.3   Detroit Traffic Test                                  7-5
                                                                     vii

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      7.3.4   10-Stop Fade and Recovery                             7~^
      7.3.5   After-Fade (A.F.) Baseline                             ~7
      7.3.6   15-Stop Fade and Recovery                             7 7
      7.3.7   Final Baseline

SECTION 8 - SAMPLING AND ANALYTICAL PROCEDURES                      8~1

8.1   Rationale Based on Collector Designs
      8.1.1   Particulate Emissions Collection
      8.1.2   Gaseous Emissions Collection
8.2   Particulate Emissions Removal From Collectors                 8~1

      8.2.1   Collection of Particulate Emissions                   8~1
      8.2.2   Disc Brake Samples                                    8~1
      8.2.3   Drum Brake Samples                                    8~3
      8.2.4   Clutch Samples                                        8~3
      8.2.5   Improved Friction Material Weighing Procedure         8~3

8.3   Analytical Problem Definition                                 8~3

      8.3.1   Composition of Wear Debris                            8~3
      8.3.2   Analytical Methods for Asbestos and Their
              Rationale                                             8~4
      8.3.3   Microscopy Methods for Asbestos                       8~°

8.4   Bendix Analytical Method for Analysis of Asbestos
      in Brake Emissions                                            8~7
      8.4.1   Criteria and Flow Chart                               8~7
      8.4.2   Analysis of Brake Emissions                           8-7
      8.4.3   Representative Sampling and Low Temperature
              Ashing (LTA)                                          8~7
      8.4.4   Sample Distribution for Microscopy                    8-12
      8.4.5   Selected Microscopy Methods                           8-15

              8.4.5.1   Initial Studies and Rationale               8-15
              8.4.5.2   Optical Microscopy Analysis for
                        Asbestos                                    8-16
              8.4.5.3   Transmission Electron Microscopy
                        Analysis for Asbestos                       8-16

      8.4.6   Calculations From Microscopy Results                  8-18

              8.4.6.1   Rationale and Microscopy Count Sheet        8-18
              8.4.6.2   Sample Calculation                          8-19
              8.4.6.3   Computerization of Calculations and
                        Particle Size Distribution                  8-26

      8.4.7   Possible Sources of Error                             8-26
viii

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8.5   Analysis of Gaseous Emissions

      8.5.1   Method of Analysis                                    8~28
      8.5.2   Gas Handling System                                   8"30
      8.5.3   Calibration of Gas Chromatograph                      8~33
      8.5.4   Problems and Interferences                            8-33

8.6   References                                                    8~36

SECTION 9 - VEHICLE TEST RESULTS                                    9~1
9.1   Vehicle Operations                                            9-1

      9.1.1   Test Scheduling and Problems Encountered              9-1
      9.1.2   Mileage Accumulations                                 9-5
      9.1.3   Reporting of Vehicle Test Data                        9-5

9.2   Performance of Emissions Collection Systems                   9-5
      9.2.1   Rotating Seal Life                                    9-5
      9.2.2   Operating Temperatures                                9-8

              9.2.2.1   Normal Brake Stops                          9-8
              9.2.2.2   Heavy-Duty Fade Stops                       9-12

      9.2.3   Collection Efficiencies                               9-15
              9.2.3.1   Recovery of Brake. Particulate Emission      9-15
              9.2.3.2   Mass Balance                                9-19
                        9.2.3.2.1   Amount of Emissions             9-19
                        9.2.3.2.2   Distribution of Emissions       9-19

9.3   Percent Asbestos Contents                                     9-24

      9.3.1   Program Results                                       9-24
      9.3.2   Battelle Analyses                                     9-28
      9.3.3   Johns-Manville Analyses                               9-28
      9.3.4   Comparison of Asbestos Analytical Results             9-28

9.4   Asbestos Emissions Factors                                    9-30
9.5   Asbestos Emissions Trends                                     9-37

      9.5.1   New versus Burnished Materials                        9-37
      9.5.2   Disc versus Drum Brake Materials                      9-37
      9.5.3   Heavy (Abusive) versus Moderate Duty                  9-39
      9.5.4   Effects of Friction Materials                         9-41
      9.5.5   Airborne versus Sump versus Surfaces Samples          9-43
9.6   Changes in Lining Wear Rate After Use at Higher
      Temperatures                                                  9-46
9.7   Results of Gaseous Emissions  Analyses                         9-46

      9.7.1   Summary of Analytical Methods Attempted               9-46
      9.7.2   Gaseous Emissions Detected                            9-48
      9.7.3   Shroud Extract Analysis                               9-53
                                                                      ix

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SECTION 10 - ESTIMATED EMISSIONS FOR CARS AND TRUCKS

10.1  Approach
10.2  Supplementary Data Base

      10.2.1  Number of Vehicles in Use
      10.2.2  Motor Vehicle Usage
      10.2.3  Estimates of Brake Usage and Abuse
      10.2.4  Asbestos in Friction Materials
      10.2.5  Amount of Friction Material Actually Worn

10.3  Interpretation of Test Results
10.4
      10.3.1
      10.3.2
        Factors Influencing Rate of Emissions
        Weighting Factors
        10.3.2.1  Distribution Weighting Factors
                  10.3.2.1.1  Location of Wear Debris
                  10.3.2.1.2  Comparison of  Normal versus
                              Shrouded Brakes
                  10.3.2.1.3  Summary
        10.3.2.2  Severity Weighting Factors
                  10.3.2.2.1  New versus Burnished
                              Friction Materials
                  10.3.2.2.2  Severe or Abusive Braking
                  10.3.2.2.3  Renewal of Friction Surface
                  10.3.2.2.4  Normal Brake Operation

        10.3.2.3  Summary
10.3.3  Asbestos Emissions Per Vehicle
        10.3.3.1  Total Asbestos Emissions Estimate
        10.3.3.2  Asbestos Emissions and Their Fate
Estimated Asbestos Emissions
10.4.1  Passenger Vehicles
        10.4.1.1  Total Asbestos Emissions
        10.4.1.2  Distribution of Asbestos Emissions
10.4.2  Trucks and Buses
        10.4.2.1  Estimated Severity Factors
        10.4.2.2  Estimated Emissions Factors
        10.4.2.3  Calculations of Total Asbestos
                  Emissions for Trucks and Buses
        10.4.2.4  Total Truck Asbestos Emissions
        10.4.2.5  Distribution of Truck Asbestos
                  Emissions
Page
10-1

10-1
10-1
10-1
10-4
10-4
10-9
10-15
10-16

10-16
10-18
10-18

10-18

10-19
10-22

10-23


10-23
10-23
10-24
10-24
10-24

10-24

10-24
10-25

10-25
10-25
10-25
10-25
10-28

10-28
10-28

10-29
10-31

10-32
x

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                                                                   Page

                            10.4.2.5.1   Estimated Distribution
                                         Weighting Factors        10-32
                            10.4.2.5.2   Truck Asbestos Emis-
                                         sions and Their Fate     10-32

       10.4.3   Estimated Asbestos Emissions                      10-32
       10.4.4   Alternate Estimate for Total Asbestos Emissions   10-34

10.5   Summary of Asbestos Emissions                              10-37
10.6   References                                                 10-38

SECTION 11 -  SUMMARY                                              11-1

APPENDIX A -  WEAR DEBRIS CALCULATIONS                              A-l

APPENDIX B -  NUCLEPORE FILTER FLOW CHARACTERISTICS FOR
              BRAKE LINING WEAR DEBRIS                              B-l

APPENDIX C -  COLLECTION OF BRAKE AND CLUTCH EMISSIONS              C-l

APPENDIX D -  ANALYSIS OF BRAKE AND CLUTCH EMISSIONS                D-l

APPENDIX E -  ELECTRON MICROSCOPY ANALYSIS OF BRAKE
              EMISSION SAMPLES                                      E-l

APPENDIX F -  COMPUTER PROGRAM FOR COMPUTATION OF ASBESTOS
              CONTENT USING ANALYTICAL MICROSCOPY TECHNIQUES        F-l

APPENDIX G -  VEHICLE TEST DATA REPORTS                             G-l

APPENDIX H -  ASBESTOS EMISSIONS ANALYSIS REPORTS FROM
              BATTELLE COLUMBUS LABORATORIES AND JOHNS-
              MANVILLE RESEARCH AND ENGINEERING CENTER              H-l
                                                                      xi

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                          LIST OF ILLUSTRATIONS
Figure No.                        Title                             Page

   2-1        Schematic Structure of Chrysotile Asbestos            2-6
   2-2        DTA and TGA Thermograms for Chrysotile Asbestos
                (Bendix Data)                                       2-6
   2-3        X-Ray Diffraction Patterns of Heated Chrysotile
                Asbestos (Bendix Data)                              2-7
   2-4        Photomicrograph of Brake Lining Cross Section
                after 8550 Miles of Test-Track Service              2-10
   2-5        Electron Micrograph of Friction Material Wear
                Debris (Made during 1966 studies.) - 10,OOOX        2-10
   2-6        Close-Up View of Bendix Drag Dynamometer
                Showing Wear Debris Collector                       2-11
   2-7        Photomicrograph of Cross Section of Friction
                Material Test Specimen after More than 10
                Successive Stops from 100 mph on Bendix1
                Full-Brake Dynamometer                              2-11
   2-8        Changes Occurring in the Friction Material as
                the Temperature Rises                               2-12
   2-9        Changes Occurring in the Rotor as the Temperature
                Rises                                               2-12
   2-10       Mechanism of Explosive Thermal Wear                   2-15
   2-11       Mechanism of Two-Body Abrasive Wear                   2-17
   2-12       Mechanism of Three-Body Abrasive Wear                 2-17
   2-13       Scanning Electron Photomicrograph Showing
                Abrasive Wear Tracks on Friction Material
                Surface and Adherent Wear Debris Particles          2-18
   2-14       Mechanism of Adhesive Wear                            2-18
   2-15       Mechanism of Fatigue Wear                             2-20
   2-16       Mechanism of Macroshear Wear                          2-20
   2-17       Predominant Wear Mechanisms of Friction
                Materials                                           2-22
   2-18       Variation of Friction Material Wear with
                Temperature                                         2-22
   4-1        Vehicle Instrumentation for Friction Material
                Testing                                             4-3
   5-1        Schematic Diagram for Air Flow of Typical
                Particulate and Gas Emission Collection System      5-3
   5-2        Air Pump Installation in Engine Compartment           5-4
   5-3        Vehicle Instrumentation (Front Seat Area)             5-6
   5-4        Vehicle Instrumentation (Rear Seat Area)              5-7
   5-5        Electrical Schematic for Particulate Trap and
                Transfer Line Heaters                               5-8
   5-6        Condensable-Gas Trap                                  5-10
   5-7        Activated-Charcoal Gas Trap - Sectional View          5-11
                                                                    xiii

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Figure No.                        Title

   5-8        Activated-Charcoal Gas  Trap -  Top View                 5-11
   5-9        Activated-Charcoal Gas  Trap                            5~12
   5-10       Exploded View of Activated-Charcoal Gas  Trap           5-13
   5-11       Gas Collection  System                                  5~15
   5-12       Sectional View  of Disc  Brake Shroud                    5-16
   5-13(a)    Major Portions  of Disc  Brake Emission Collector
                                                                     S  1 7
                Assembly                                             J--L/
   5-13(b)    Major Portions  of Disc  Brake Emission Collector
                Assembly
   5-14       Disc Brake Emission Collector  Assembly -
                Exploded View                                       5   9
   5-15       Front Disc Brake Emission Collector Installed
                on Vehicle                                           5~20
   5-16       Back View of Front Disc Brake  Emissions  Collector
                                                                     S—21
                Showing Instrumentation                              J
   5-17       Initial Design  (Mkl) for Rotating Seal of Disc
                Brake Collector                                      5-22
   5-18       Rotating Seal for Disc  Brake Emission Collector        5-23
   5-19       Details of Disc Brake Collector Rotating Seal          5-24
   5-20       Front Disc Brake Emissions Collector Showing
                Thermal Control Aids                                 5-25
   5-21       Right Front Wheel of Test Vehicle                      5-26
   5-22       First Seal Design (Mkl) for Drum Brake)                5-27
   5-23       Mkll Rotating Seal for  Drum Brake Emission
                Collector                                            5-28
   5-24       Details of Mkll Rotating Seal                          5-29
   5-25       Rear Drum Brake Emission Collector                     5-30
   5-26       Rear View'of Rear Drum  Brake Emissions Collector
                Showing Instrumentation                              5-32
   5-27       Completely Worn Seal from MKII Rear Drum Brake
                Collector                                            5-32
   5-28       Sectional View  of Drum  Brake Shroud (MKIII)            5-33
   5-29       Outboard View of Rear Drum Brake Emissions
                Collector Interior                                   5-34
   5-30       Assembled Rear  Drum Brake Emissions Collector          5-35
   5-31       Inboard View of Assembled Rear Drum Brake
                Emissions Collector                                  5-36
   5-32       Emission Collection System for Clutch                  5-37
   5-33       General View of Covered Clutch                        5-38
   6-1        Disc Brake and  Emissions Collector Assembly
                Installed on  Dynamometer                             6-3
   6-2        Disc Brake Comparative  Thermal Response  Time
                (Static Air)                                         6-4
   6-3        Comparative Thermal Response Tests on a
                Disc Brake                                           6-4
   6-4        Seal Leakage versus Flow for Disc Brake  Emissions
                Collector Showing Differences between  Dry and
                Lubricated Seals                                     6-5
xiv

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Figure No.                        Title

   6-5        Seal Leakage Rate versus Speed Showing
                Differences between New and Used Seal               6-5
   6-6        Seals from Disc Brake Emissions Collector
                Showing Normal and Abnormal Wear                    6-6
   6-7        Rotating Seal Leakage Rate versus Wheel Speed
                for Disc Brake Emissions Collector                  6-8
   6-8        Disc Brake Emission Collector Temperature             6-9
   8-1        Thermal Analysis of Wear Debris                       8-5
   8-2        Flow Chart for Particulates Analyses                  8-9
   8-3        Representative Sampling for Analysis                  8-10
   8-4        Wear Debris Collected on 8u Nuclepore Filter          8-10
   8-5        Low Temperature Ashing                                8-11
   8-6        SEM Photomicrographs of LTA Wear Debris Samples       8-13
   8-7        Uniform Sample Distribution onto Filter               8-14
   8-8        Phase Contrast Optical Microscopy at 400X             8-17
   8-9        Phase-Contrast Photomicrograph of Wear
                Debris - 400X                                       8-17
   8-10       Transmission Electron Microscope                      8-18
   8-11       Asbestos Fiber in Brake Emission                      8-20
   8-12       Microscopy Count Sheet                                8-21
   8-13       Fiber Volume Calculations                             8-22
   8-14       Computer Printout of Asbestos Analytical Results      8-23
   8-15       Variation of Maximum Deviation of Asbestos
                Analytical Results with Asbestos Percent Found      8-30
   8-16       Gas Handling System                                   8-31
   8-17       Gas Handling System and Gas Chromatograph             8-32
   8-18       Detector Response for Carbon Dioxide                  8-34
   8-19       Typical Calibration Chromatogram for Low
                Molecular Weight Gas                                8-35
   9-1        Brake Temperature Data - Vehicle Test 1,
                10-Stop Fade                                        9-13
   9-2        Brake Temperature Data - Vehicle Test 1,
                15-Stop Fade                                        9-14
   9-3        Decrease in Clutch Airborne Asbestos Emissions
                with Continued Normal-Duty Service                  9-39
   9-4        Variation of Asbestos Emissions During Moderate
                Duty with Asbestos Content of Disc Pads             9-42
  10-1        Frequency Distribution of Braking Decelerations      10-11
  10-2        Variation of Wear Debris Retention with Mileage
                (for Rear Drum Brakes)                             10-22
                                                                      xv

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                             LIST OF TABLES
Table No.                         Title

   2-1        Composition of Typical Automotive Friction
                Materials (Volume Percent)
   2-2        Wear Mechanisms in Friction Materials
   3-1        Vehicle Configurations and Lining Selections
   3-2        Surface Roughness Measurements on Turned Discs
                and Drums for Vehicle Test 3
   3-3        Estimated Asbestos Content
   4-1        Test Vehicle Description
   6-1        Summary of Dynamometer Test Results
   7-1        Detroit Traffic Test Route (Modified)
   7-2        Vehicle Test Schedule
   8-1        Comparison of Disc Brake versus Drum Brake
                Operating Conditions
   8-2        Samples Produced by Brake Emissions Collection
   8-3        Estimated Chemical Composition Characteristics
                of Wear Debris
   8-4        Transmission  Electron Microscopy Methods
   8-5        Sample Calculation
   8-6        Possible Sources of Error
   8-7        Extent of Error in Asbestos Emissions
                Analytical Results
   9-1        Actual versus Estimated Test Schedules for
                Vehicle Test 1
   9-2        Actual versus Estimated Test Schedules for
                Vehicle Test 2
   9-3        Actual versus Estimated Test Schedules for
                Vehicle Test 3
   9-4        Summary of Vehicle Mileage Accumulations
   9-5        Running Log of the Rotating Seals Mileages
                Obtained in the Vehicle Test Program
   9-6        Rotating Seal Life (Miles)
   9-7        Brake Temperatures During Burnish Tests (°F)
                (Vehicle Test 1)
   9-8        Brake Temperatures During Detroit Traffic Circuits
                (Vehicle Test 2 - A.B. Baseline)
   9-9        Weights of Brake Particulate Wear Debris
                Collected (Vehicle Test 1) (gm)
   9-10       Weights of Particulate Wear Debris Collected
                (Vehicle Test 2) (gm)
   9-11       Weights of Brake Particulate Wear Debris
                Collected (Vehicle Test 3) (gm)
   9-12       Brake Friction Material Initial Weights and
                Weight Losses (gm)
   9-13       Material Percent Recovery as Particulate
                Emissions (Vehicle Test 1)
                                                                    xvii

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Table No.                         Title                             Page

   9-14      Material Percent Recovery as Particulate Emissions
               (Vehicle Test 2)                                      9-22
   9-15      Material Percent Recovery as Particulate Emissions
               (Vehicle Test 3)                                      9-23
   9-16      Summary of Asbestos Analytical Restuls (Vehicle
               Test 1) (Weight Percent)                              9-25
   9-17      Summary of Asbestos Analytical Results (Vehicle
               Test 2) (Weight Percent)                              9-26
   9-18      Summary of Asbestos Analytical Results (Vehicle
               Test 3) (Weight Percent)                              9-27
   9-19      Comparison of Analytical Results for Asbestos           9-29
   9-20      Weight of Asbestos Generated During Braking
               (Vehicle Test 1) (mg)                                 9-31
   9-21      Weight of Asbestos Generated During Braking
               (Vehicle Test 2) (mg)                                 9-32
   9-22      Weight of Asbestos Generated During Braking
               (Vehicle Test 3) (mg)                                 9-33
   9-23      Weight of Asbestos Generated During Braking
               (Vehicle Test 1) (pg/mile)                            9-34
   9-24      Weight of Asbestos Generated During Braking
               (Vehicle Test 2) (yg/mile)                            9-35
   9-25      Weight of Asbestos Generated During Braking
               (Vehicle Test 3) (yg/mile)                            9-36
   9-26      Summary of Clutch Asbestos Emissions                    9-38
   9-27      Comparison of Asbestos Emission from New and
               Burnished Materials                                   9-38
   9-28      Asbestos Emissions from Heavy-Duty Tests                9-40
   9-29      Comparison of Asbestos Emissions Generated by
               Different Friction Materials                          9-42
   9-30      Comparison of Asbestos Emissions for Various
               Sample Locations (yg/mile)                            9-44
   9-31      Summary Comparison of Surfaces, Sump, and Airborne
               Samples                                               9-45
   9-32      Change in Lining Wear Rate after Operation at
               Increased Temperatures  (Vehicle Test 2)               9-47
   9-33      Data Analysis of Gaseous Emissions (Vehicle Test 1)     9-49
   9-34      Data from Analysis of Gaseous Emissions
               (Vehicle Test 2)                                      9_50
   9-35      Elution Order from Poropak Q                            9-51
   9-36      Elution Order from W-98                                 9-52
  10-1       U. S. Braked Motor Vehicle Population                  in 2
  10-2       U. S. Braked Trailer Population                    '    -,« ?
  10-3       U. S. Motor Vehicles with Dry Clutches                 103
  10-4       Yearly Additions to U.  S.  Braked Vehicle  Population    inl*
  10-5       Motor Vehicle Usage by Vehicle Type and Roadway        Tn s
  10-6       Type and Usage of Public Roads                         10-5
  10-7       Motor Vehicle Usage by Purpose of Trip                 10-6
  10-8       Motor Vehicle Usage by Length of Trip                  1Q-6
kviii

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Table No.
Title
  10-9       Results  of  Cross-Country Brake Test Trip                10-8
  10-10     Where Vehicles  Are Used                                10-8
  10-11     Some U.  S.  Driving Characteristics                      10-10
  10-12     Brake Applications Per Mile                            10-10
  10-13     Asbestos Content of Automotive Friction Materials       10-11
  10-14     Brake Friction  Material Weights for Test  Vehicle       10-12
  10-15     Number of Newly Surfaced Rotors Used Each Year         10-12
  10-16     Compilation of  Annual Motor Vehicle Brake Friction
              Material  Usage                                       10-13
  10-17     Compilation of  Annual Clutch Friction Material
              Usage                                                 10-14
  10-18     Relative Brake  Relining Frequency                      10-14
  10-19     Total Asbestos  Emissions Calculated from  the  Test
              Vehicle (Average for the  Three Vehicle  Tests)         10-26
  10-20     Distribution-Weighted Asbestos Emissions  from the
              Test Vehicle                                          10-27
  10-21     Estimate for Total Asbestos Emissions Expected for
              a Light Truck                                        10-29
  10-22     Estimate of Total Asbestos  Emissions Expected for
              a Medium  Truck                                       10-30
  10-23     Estimate of Total Asbestos  Emissions Expected for
              a Heavy Truck                                        10-30
  10-24     Distribution-Weighted Asbestos Emissions  from a
              Light  Truck                                          10-31
  10-25     Summary  of  All  Brake and Clutch Emissions
              (Ibs per  year)                                       10-31
  10-26     Calculation of  Weighted Average Unconverted
              Asbestos  Percent for Sump Sample                      10-34
  10-27     Calculation of  Weighted Average Asbestos  Percent
              for Surfaces  Sample                                  10-34
  10-28     Calculation of  Weighted Average Asbestos  Percent
              for Airborne  Samples                                 10-36
  10-29     Data and Calculation of Weighted Asbestos Percent
              for All Vehicles.                                    10-36
                                                                     xix

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                               SECTION 1

                    INTRODUCTION AND BRIEF SUMMARY
      The chrysotile form of asbestos is a major constituent in automo-
tive brake linings and disc pads, and in the friction materials used in
clutches.  These components are expendable.  In typical passenger car
service, drum linings wear out in about 40,000 miles, disc pads in about
30,000 miles, and clutch facings in about 70,000 miles.  There are,  of
course, wide variations in the service lives of these components, which
depend on the nature of the friction materials used, on driver habits,
and on driving conditions.
      The expendable members of the common automotive friction couples
contain not only asbestos, but also various organic and inorganic fric-
tion and property modifiers.  These constituents are bound together by
phenolic resins.  Because of their high content of organic substances,
such friction materials are classified as "organic."  Asbestos-free
friction materials with a high content of metallic substances are classi-
fied as "semi-metallic."  Over 99 percent of the automotive friction ma-
terials used today are organics.

      The mechanisms by which organic friction materials wear can be
classified under five headings:  thermal, abrasive, adhesive, macroshear,
and fatigue.  Thermal, abrasive, and adhesive wear are considered to be
the most important mechanisms, thermal wear predominating above 450°F,
abrasive and adhesive wear predominating below 450°F (the temperature
being measured by a thermocouple in the rotor, about 0.050 inch from
the sliding interface).  The organic constituents pyrolyze or oxidize,
and are emitted to the air as carbonaceous solid particles or gaseous
reaction products.  The asbestos fibers are pulverized into small parti-
cles which are trapped in the brake (or clutch) housing, or fall to the
road, or are emitted to the air.  Disc brakes do not trap as much as
drum brakes.  Most of the asbestos is heated to temperatures high enough
to cause chemical conversion, and is therefore trapped or emitted as
olivine or forsterite particles.

      When the large number of existing cars and trucks is considered,
each with eight or more pieces of friction material in the brake system,
plus more in the clutch mechanism, it becomes apparent that an air pollu-
tion problem may exist.  Considered in another light, there are perhaps
one billion pieces of friction material in vehicles in the United States,
gradually being pyrolyzed and ground to dust.  The brake systems in the
vehicles utilizing these friction materials can thus be considered as
chemical reactors, each emitting organic and inorganic compounds, includ-
ing asbestos and its decomposition products, to the atmosphere.  The com-
positions of the gaseous and solid emissions have not been well known,
                                                                     1-1

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and the particle sizes and shapes of the solid emissions have not been
well known.  Because of the possible damage which these emissions can
produce in human respiratory systems, it is desirable to identify and
quantify them, with particular regard to asbestos.  That is the purpose
of the program described in this report.
      The amount of asbestos emitted is a function of many variables:

        the number of vehicles on the road,
        the number of miles driven per year by each,

        vehicle size,
        the number of vehicles using manual clutches,
        conditions of driving (city, expressway, mountain;
        driver habits, etc.),
        brake system design, and
        brake type (drum or disc),
        rotor condition (surface roughness, scoring, cracking,
        pitting, etc.),
        rotor design  (e.g., solid or ventilated discs, finned
        drums, etc.),
        rotor metallurgy (cast iron or aluminum),
        volume percent of asbestos in the friction material, and

        inherent wear resistance of the friction material.

 In this program a passenger car of medium weight  (test weight:  4800
 pounds), produced in high volume, was used.  It was equipped with a
 manual  transmission and clutch, ventilated cast iron disc brakes on the
 front,  and  standard cast iron drum brakes on the  rear.

      A passenger car was selected for testing because of the following
 factors:
       (1)   vehicle braking cannot be simulated realistically on
            small-scale friction test-machines with the present
            state of the art;

       (2)   full-scale brake and clutch dynamometers provide fairly
            good simulation, and can be used for checking out the
            emissions  collection system; separate  tests for brakes
            and clutches would be required, however, thus increasing
            program costs, whereas on the vehicle, disc and drum
            brakes and clutches can be tested simultaneously;

       (3)   air flow in the dynamometers differs from that in vehicles,
            and emissions from drum brakes will therefore be different
            in the two cases.
 1-2

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      Three series of tests were run, using friction materials as tabulated
below:

Vehicle            .           Friction                  ,,    ,
 T  .        Simulation        „ .   .  n                  Remarks
 Test                         Materials

  1          Original      OEM1 Disc Front     Class A organic disc pads
             Equipment     „„„ „
              M  y         OEM Drum Rear

  2          Partial       AM2 Disc Front      No metallic chips;
                           Used OEM Drum       Discs and drums not
                           Rears               turned

  3          Full          AM Disc Front       Disc pads and secondaries
             Reline        AM Drum Rear        contain brass chips
                                               Discs and drums turned

This  selection has several features.   It provides a replication of one
test, thus giving an estimate of repeatability.  It includes a primary/
secondary combination that serves both OEM and aftermarkets.  It includes
one combination (two materials) of widely used OEM materials.  It includes
one combination (two materials) from one of the larger aftermarket sup-
pliers.  It includes a set of used linings (about 3,000 miles) to give
data  on the emissions at various stages of lining life.  It includes two
different disc pad materials from two of the larger aftermarket suppliers.
Five  different manufacturers were represented in the friction material
selections.
      The collection of particulate and gaseous emissions from any vehicle
friction couple has never before, to the authors'  knowledge,been reported
in the literature.  To define the extent of these emissions, a combination
separation and storage collection system was devised.  Unique emissions
collectors for both disc and drum brakes, and for a clutch, were conceived,
designed, and built as the main embodiment of this instrumentation.  The
collectors separated the wear debris into three different fractions:  a
sump  sample which included the wear debris on the lining surfaces, in the
rivet holes, and on the brake drum; a surfaces sample which included
the wear debris on the brake and collector shroud surfaces; and an airborne
sample collected on membrane filters.

      The vehicle was equipped with standard brake test instrumentation.
A front disc brake collector and a rear drum brake collector were installed
on the right side of the vehicle.  The clutch was sealed by closing the
•'•OEM - Original Equipment Manufacturers
2AM - aftermarket
                                                                     1-3

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holes in its casing.  The left wheel brakes were left  in their  normal
configuration and were used to monitor the operation of  the shrouded
brakes.  Wear debris was also taken from the left brakes;  the amounts  of
debris collected and its composition were used to demonstrate that  the
brake shrouding did not significantly affect the operation of the brakes
within the emissions collectors.
      Although there are many acceptable original equipment manufacturers
brake and friction material tests for measuring a specific collection  or
combination of collections, no one test adequately matches driving  con-
ditions which would be representative of all vehicles.   Consequently,  it
became necessary to devise a rational and meaningful vehicle test.  A
total of seven schedules were chosen and each was followed by a measure-
ments procedure (take emissions samples, measure wear, inspect  systems,
and replace worn parts).  The first three schedules  -  Burnish,  After
Burnish (A.B.) Baseline, and Detroit Traffic - Represented low-temperature
testing.  The final four schedules - 10-Stop Fade, After Fade (A.F.) Base-
line, 15-Stop Fade, and Final Baseline - represented high-temperature  and
abrusive testing.
      The mileage accumulations for each schedule of each vehicle test
verified the possible test mileage reproducibility.  A critical component
of the front disc brake collector was a unique rotating  seal.  For  the
8100 miles of testing, only eight rotating seals were  required  — an ex-
ceptional improvement over the anticipated need at the start of the
program.
      Prior to vehicle test 1, a Burnish schedule was  performed and the
temperatures for the right front disc brake were found to be near 400°F.
The temperature difference, AT, between the right and  left front brakes
ranged from 200 to 250°F.  This was unacceptable. The addition of  several
thermal control aids reduced the AT to a range of 115  to 160°F. Most  import-
ant was the reduction of the right front brake operating temperature from
about 400°F to about 300°F.  The brake shrouding did not present any pro-
blems on hot days.  During the Detroit Traffic Test, the AT between the
front brakes remained between 100 and 140°F while that for the  rear drum
brake remained between 10 and 30°F.

      The range of asbestos content in the brake emissions for  vehicle
tests 1 and 2 went from a high of 1.65 percent to a  low  of 0.03 percent
for the 90 analyses; only three were above 1.00 percent.  The overall
average for vehicle test 1 was 0.40 percent and for  vehicle test 2  was
0.25 percent.  For vehicle test 3, the range of asbestos content was
from a high of 0.51 percent to a low of 0.003 percent.   The overall aver-
age was 0.07 percent.  In this work, all values for  heavy-duty  (abusive)
braking were less than one percent, which is significantly less than  the
15 percent asbestos content reported by Lynch of the U.S. Public Health
Service.

      To provide a systematic, independent check on  the  asbestos analyses,
the EPA Project Officer arranged a second contract for Battelle Columbus
Laboratories to analyze twenty-four samples generated  by Bendix Research
1-4

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Laboratories.  Johns-Manville also provided three analyses.   The Johns-
Manville and Battelle data agreed very well.  In 19 of the 24 analyses,
the Bendix results were slightly higher than the corresponding Battelle
results.  The Bendix average was 0.25 percent, while the Battelle aver-
age was 0.17 percent, or 68 percent of the Bendix average.  The Bendix
data were expected to be higher for the following reasons:  all fibers
found were assumed to be cylinders of projected diameter and length,  and
a fiber with an elliptical cross section was actually smaller in volume
than reported; and all fibers were assumed to be pure asbestos, (partially
degraded asbestos  or olivine fibers were mechanically reduced to non-
fibrous material by the other analytical techniques, so only the stronger
asbestos fibrils that remained were counted).
      Analysis of the gaseous emissions was made difficult by the large
quantities of water and carbon dioxide which by-passed the gas condition-
ing trap and entered through the rotating seals.  Most samples showed
traces of C^ to 63 hydrocarbons only as lower concentrations of higher
molecular weight gases could not be detected.  When the gases were con-
centrated from the fade tests, C^ to Cg compounds such as butanes, ben-
zene, toluene, phenol, and cresols were detected in the gas  traps.  The
corresponding shroud extracts showed C^2 to ^30 materials, including
cardanol.

      To compare the generation of asbestos emissions properly, it was
found necessary to calculate the emissions factors for each  sample in
micrograms/mile (yg/mile).  These values were obtained by multiplying
the weight of generated brake debris by the appropriate asbestos percent,
followed by dividing by the miles per test schedule.  Thus,  either a
high asbestos content or a large sample gave a high factor.

      The following observations were made:

      •  Asbestos emissions were higher for new friction surfaces
         and decreased with use.
      •  Initially the drum brake produced more asbestos emissions than
         the disc brake.  The difference decreased as the materials
         continued to be used.

      •  Heavy (abusive) duty did not necessarily give a higher percent
         asbestos, however, the large amount of debris produced gave
         a significant rise in asbestos emissions.

      •  The order of decreasing asbestos emissions from brakes was
         found to be:

           Fade or heavy-duty stops      . ^
                                         1 Decreased
           Burnish                       |  asbestos
           Moderate braking
J
                                                                    1-5

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         For the disc pads only, there was an increase in asbestos
         emissions with increased asbestos content in the friction
         material (there was no such trend for the drum brake
         materials) .
         Both the front disc pads and the drum linings of vehicle
         test 3 had wear comparable to that of the other two vehicle
         tests, yet the asbestos emissions were significantly lower.
         Both pads and linings contained brass chips which may have
         been in part responsible for the more complete conversion
         of the asbestos in the brake emissions, possibly because
         of better heat transfer to the asbestos.

         For both disc and drum brakes, the surfaces sample was
         the largest of the three (^92 percent), the sump sample
         was next ('W percent) , and the airborne sample was the
         smallest (^1 percent).
      Two series of weighting factors were developed.  The distribution
weighting factors were calculated from the material recoveries in the
shrouded and unshrouded brakes as indicated earlier.  Estimates were made
for both disc and drum brakes from the test vehicle for the amounts of
the different samples distributed from the brakes.  These estimates were
made for the Burnish schedule, for the end of a complete vehicle test,
and for the end of all three vehicle tests.  For the drum brake, estimates
were made up to 40,000 miles.  The severity weighting factors were cal-
culated from the percentages of different braking modes:   for new versus
burnished friction materials, for severe (or abusive) versus moderate
braking, and for the renewal of friction surfaces (A.F.  Baseline).

      The total asbestos emissions estimate for the test vehicle was
calculated from the asbestos emissions factors and the severity weighting
factors.  The average asbestos emissions factor for the disc brakes,  drum
brakes, and clutch were used along with the Burnish (new surfaces),  A.  B.
Baseline (surface preparation) , Detroit Traffic (moderate braking) ,  10-
Stop Fade (severe braking) and A. F.  Baseline (surface renewal)  weighting
factors.  The value obtained for the test vehicle was 28.51  yg/mile.

      The fate of the asbestos emissions was calculated with the use of
the distribution weighting factors as follows:
      Road Drop-out      81.9%
      Airborne:           3.7%
      Brake Retention:   14.4%
      The annual total asbestos emissions  estimate for 96,400,000 pass-
enger vehicles travelling an average  of 9,978 miles per year was found
to be 60,400 pounds, distributed as follows:
      Road Drop-out:     49,470 Ibs

      Airborne:           2,230 Ibs
      Brake Retention:     8,700 Ibs
                         60,400  Ibs
 1-6

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      The annual total asbestos emissions estimates for light trucks,
medium trucks  (and buses), and heavy trucks were found to be:
      Light trucks
      Medium trucks
       (and buses)
      Heavy trucks
32,300 Ibs

16,300 Ibs
22,900
                       81,500 Ibs
The  distribution of the total asbestos emissions estimate for trucks was
calculated to be as follows:
      Road Drop-Out:    87.9%
      Airborne:          2.9%
      Brake Retention:   9.2%
      The estimated asbestos emissions for all vehicles in pounds/year
is summarized as follows:
                      Total Asbestos
                     Emissions (Ibs)
                      Distribution  (Ibs)
                 Drop-Out    Airborne   Retention
Passenger Cars
Light Trucks
Medium Trucks (and
  buses)
Heavy Trucks
Miscellaneous
  (motorcycles,
  trailers, etc.)
Distribution by
  percent:
60,400
32,300
16,300
32,900
16,300
158,200
49,470
28,420
14,330
28,920
14,330
135,470
2,230
940
470
950
470
5,060
8,700
2,940
1,500
3,030
1,500
17,670
                   85.6%
3.2%
11.2%
These estimates are considered to be maximum values.
                                                                     1-7

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                               SECTION 2

                      OBJECTIVES AND BACKGROUND
 2.1   OBJECTIVES

      2.1.1   Objectives of this Program
              The objectives of this program, as stated in the Request
 for Proposal and in the Contract, were as follows:

      "In order to define the extent of non-engine asbestos
      emissions, the Office of Air Programs of the Environmental
      Protection Agency is seeking the assessment of these emis-
      sions on a single vehicle basis.  The efforts are to include
      emissions measurements from several different types of brakes
      as well as a clutch assembly.  The end objective of the work
      will be the documentation of these emissions to assess their
      overall contribution to the atmosphere."

      2.1.2   Bendix Technical Approach

      2.1.2.1   Select Suitable Vehicle and Friction Materials
                For the results to be representative of the average
 consumer-type vehicle usage, it was necessary to select a vehicle inter-
mediate between the compacts and luxury vehicles.  Moreoever, it was
 desirable to select a vehicle with original-equipment friction materials,
produced by more than one supplier, and equipped with a clutch.  After-
market friction materials, produced by several manufacturers, were also
 selected.

      2.1.2.2   Conceive, Design, and Build Brake and Clutch
                Emissions Collectors
                Since only 100-percent collection could give a mass
balance, it was necessary to conceive, design, and build brake and clutch
emissions collectors which could collect all the emissions and differen-
tiate among wear debris remaining on the friction materials, debris re-
maining on the local surfaces of the foundation brakes, and debris entering
the atmosphere.  Moreoever, provision was necessary for the collection and
storage of gaseous decomposition products.

      2.1.2.3   Test a Typical Collector and Instrument the Vehicle

                To ensure that the concepts and hardware were technically
sound, it was necessary to install the most critical collector on an
inertial dynamometer to verify its operation.  Once proven, that collector
and the others, along with brake test instrumentation, could be installed
on the vehicle.
                                                                    2-1

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      2.1.2.4   Select and Run Suitable Driving Test Schedules
                Because of the wide variety of driving which takes place
throughout the various regions of the country, it was necessary to select
a vehicle test program in which brake emissions could be collected for
new brake linings and rotor combinations.  The program included typical
consumer-type driving on flat terrain, and heavier-duty braking as en-
countered in hilly areas.

      2.1.2.5   Collect and Analyze Emissions
                As the main goals were to determine the asbestos content
of the emissions and their particle-size distributions, it was necessary
to select an analytical method which would not disturb the particle size
distribution and yet be sensitive to very small amounts of asbestos.
Further, it was necessary to collect and separate very low concentra-
tions of gaseous emissions from extremely large quantities of air and
other molecules present in large concentrations.

      2.1.2.6   Estimate Asbestos Emissions for Cars and Trucks
                Because of funding and time limitations, only a few
selected tests could be run.  Based on the measurements taken and a
knowledge of the overall vehicle population, it was possible to prepare
estimates for total emissions from cars and trucks operating in the
United States.

2.2   PRIOR WORK

      2.2.1   Published Data

              The only known published data on asbestos emissions were
those reported by Jermiah Lynch of the U.S. Public Health Service,
Department of Health, Education, and Welfare.(2-1)*

              The paper discusses tests which were performed with brake
test machines, using one-inch-square samples,  and tests performed on  an
inertial dynamometer where a complete brake and clutch were used.   Emis-
sions samples were collected on membrane filters  and analyzed by electron
microscopy.  In all but a few tests, the drum brake linings showed less
than 1 percent free fiber in the decomposition product.  In some tests
reported, where the lining temperatures were extremely high and accompanied
by a rapid drop in coefficient of friction (fade), a significant mass of
free fiber was released - approximately 10 to 15  percent.   The clutch
test gave no asbestos fiber.
*
 Numbers in parentheses designate References at end of section.
2-2

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      2.2.2   Unpublished Data

              At the time of writing of this report, there were three
known works which had been completed or were in progress.  The amount
of brake wear debris and its composition were determined on a full-brake
inertial dynamometer using a duo-servo drum brake in 1968-69.'^  '  The
determination of the amount of asbestos in airborne brake debris sampled
downwind of a disc brake installed on an inertial dynamometer was in
progress.(2~3)  The determination of asbestos content in airborne brake
debris sampled downwind of vehicle-mounted disc and drum brakes was also
in progress.(2-4)

2.3   BACKGROUND

      2.3.1   Energy Absorption by Friction Materials

      2.3.1.1   Brakes
                During a stop, the automobile brake converts the kinetic
energy of the moving vehicle into heat, absorbs the heat, and gradually
dissipates it to the atmosphere.  The sliding friction couple in the
brake consists of a cast-iron rotor (drum or disc) and a stator on which
is mounted a friction material or lining consisting of asbestos fiber,
property modifiers, and an organic resin binder.  Lining is considered
expendable.  Over a long period of time and many miles of service, much
of it is converted to dust and gases.  Smaller amounts of the rotor are
also converted to wear debris.  Particulate debris is partially retained
and partially emitted from the vehicle in normal service.

      2.3.1.2   Clutches
                The "manual" automobile clutch transfers the kinetic
energy of the engines rotating crankshaft smoothly to the transmission
and wheels.  Any slippage results in generation of heat, which is ab-
sorbed and eventually dissipated to the atmosphere by the clutch.  Thus
the clutch is basically a dry-running static friction couple (which
slides momentarily during gear shifts).  The mating materials are usually
cast-iron or steel and a friction material or lining which is frequently
organic-bound.  Organic-bound friction materials consist of asbestos
fiber reinforcement, property modifiers, and an organic resin binder.
The composition is qualitatively similar to that of brake linings.
Clutch linings are also expendable, gradually wearing away in use.  The
wear debris can escape from manual clutches.  Wear debris from friction
materials in automatic transmissions is retained almost completely in
the transmission fluid.
                                                                     2-3

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      2.3.2   Compositions of Friction Materials

      2.3.2.1   Generalized Classifications
                Table 2-1 gives typical compositions of drum lining, disc
pad,(2~5) and clutch facing friction materials.   The foundation, or major
constituent, of practically all organic friction materials is asbestos
fiber.  Asbestos is chosen because of its thermal stability, its relatively
high friction level, and its reinforcing properties.  Since asbestos alone
does not offer all of the desired friction properties, other materials
called friction modifiers are added.  Modifiers  are varied in type and
content to provide desired levels of effectiveness, wear,  fade, recovery,
and noise.  A resin binder is also added to hold the other materials
together with adequate strength.

      2.3.2.2   Asbestos

                The asbestos usually used in friction materials is chry-
sotile from Quebec or Vermont.  Chrysotile, the  principal  mineral of the
serpentine group, has the approximate composition formula
                                 or  3Mg0.2Si02-2H20
    Table  2-1 -  Composition of Typical Automotive Friction Materials
                (Volume Percent)
Resin Binder
Asbestos Reinforcement
Friction Modifiers
• Organic
Friction Dust
Elastomer
• Inorganic
Garb ons /Graphites
Zinc Chips
Oxides
Copper/Brass
Misc. Inorganics
Sulfur
Drum Linings
Primary
20-30
Major


10-15








Secondary
25-35
Major


5-15
5-15



0-5
0-5
5-10

Disc Pads
Class A
Standard
18-22
Major


20-25
10-15

1-2
1-2


0-5

Class B
Heavy-Duty
15-18
Major


0-15
0-10

2-15

2-7
5-10
5-15

Woven Clutch Facings
Standard
20-30
Major







0-5
0-5
5-10
2-5
Heavy-Duty
15-25
Major







0-5
5-10
5-10
2-5
2-4

-------
Structurally, it is a pseudohexagonal network of Si04 tetrahedra forming
a sheet in which all the tetrahedra point one way.  A layer of brucite,
Mg(OH)2, is joined to the 8104 network in such a way that, on one side,
two out of every three hydroxyls are replaced by oxygens at the apices
of the tetrahedra (Figure 2-1).  The macromolecule consists of parallel
sheets of brucite-silica layers structured in cylindrical lattices in-
volving closed concentric cylinders, spirals, and sometimes helical
arrangements.(2-6)

                Bendix Research Laboratories' scientists have been study-
ing asbestos for several years.  Figure 2-2 presents the results of dif-
ferential thermal analysis (DTA) and thermogravimetric analysis (TGA)
studies for a common short-fiber grade of chrysotile asbestos.(2-7)  The
transition at approximately 700°F (370°C), in both the DTA and the TGA
thermograms represents the dehydration of the brucite (magnesium hydrox-
ide) , the 1.4 percent weight loss corresponding to an approximate con-
centration of 4.5 percent brucite.  The transition at 1250°F (680°C) in
both thermograms represents the major dehydroxylation reaction in chrys-
otile asbestos.  At 1580°F (860°C), a sharp exotherm, not associated with
any weight change, represents the conversion of the dehydroxylated chrys-
otile to forsterite (2MgO'Si02) or olivine [2(Mgl.oO-xFex)0
-------
                                                 H     H
                                          H HYDROGEN
                                          • OXYGEN
                                          O MAGNESIUM
                                          0 SILICON
                        SHEETS ARE CONTINUOUS IN DIRECTION OF CURVATURE AND NORMAL
                       TO PLANE OF SECTION; FIBER AXIS IS ALSO NORMAL TO PLANE OF SECTION.
           Figure 2-1 - Schematic  Structure of  Chrysotile Asbestos
                            I
                       -  O.S°C/IN.
                       :T
                              ,1.0% MOISTURE
                                               1.4% LOSS
20°C/MIN
1   |  I
'  I  I
                                                I    I
                                                          11.5% LOSS
                           100  200   300  400   BOO   600  700   800  900  1000 °C
                           200   400   600   800   1000   1200   1400   1600  1800 °F
                                          TEMPERATURE
        Figure 2-2 -  DTA  and  TGA Thermograms for Chrysotile  Asbestos
                        (Bendix  Data)
2-6

-------
                                                                CHRYSOTILE
       104   96    88   80   72   64   56    48   40   32    24    16

                            26 ANGLE (DEGREES)
      104    96   88   80   72   64    56   48   40    32   24   16
                                                                FORSTERITE
Figure  2-3 - X-Ray  Diffraction Pattern of Heated Chrysotile Asbestos
              (Bendix  Data)
                                                                          2-7

-------
      2.3.2.4.1   Non-Abrasive Modifiers
                  Nonabrasive friction modifiers can be classified further
as low friction and high friction.  The most common and best known of the
high-friction materials is known as friction dust.  This is a cured resi-
nous material.  The most frequently used variety is derived from cured
or polymerized cashew-nut-shell liquid, chemically a phenolic compound.
When heated with hardening agents, such as hexamethylenetetramine or
formaldehyde, it becomes sufficiently hard or polymerized to be granu-
lated.  Many other cured resinous or polymeric materials, some with
fillers, are also used.  Certain friction dusts are combinations of these
materials and cashew resin.  Ground rubber is normally used in particle
sizes similar to, or slightly coarser than, those of the cashew friction
dusts for noise, wear, and abrasion control.
                  Carbon black, graphite, petroleum coke flour, or other
carbonaceous materials may also be added as friction modifiers to lower
the friction coefficient or to reduce noise.  These materials are normally
used in the form of fine powders or particles, although graphite is some-
times used in coarse particles or pellets.  The amount of friction modi-
fier added is dependent upon the properties desired in the final composite.

      2.3.2.4.2   Abrasive Modifiers
                  Abrasive modifiers, such as alumina and the silicas, are
usually used in relatively small amounts and only in very fine particle
sizes (generally 100 mesh or finer).  Particle size is limited by the
fact that large particles of such hard materials would groove and wear
the mating surfaces.  Minerals are generally added to improve wear resis-
tance at minimum cost.  Those most commonly used are ground limestone
(whiting) and barytes  (barium sulphate), though various types of clay,
finely  divided silicas, and other inexpensive or abundant inorganic
powders may  also perform this function.  Such materials are inorganic
in nature and tend to  detract from noise properties and mating surface
comp at ib ili ty.
                  Metals or metal oxides may also be added to perform spe-
cific functions.  Brass chips are frequently found in heavy-duty friction
materials where, as scavengers,  they break up undesirable surface films.
Zinc and  aluminum are  also used.  Zinc chips, in relatively small amounts,
can  contribute  significantly to  recovery of normal performance following
fade.

      2.3.3   Friction Material  Reactions

      2.3.3.1   Absorption and Conversion of Energy

                 The automobile brake converts the kinetic energy of the
moving  vehicle  into heat,  absorbs the heat, and eventually dissipates
 it to the atmosphere.   The clutch absorbs the friction energy generated
when the transmission and  drive-shaft  are engaged or disengaged on manual
 2-8

-------
transmission vehicles.  Phenolic-bound brake lining compositions contain-
ing asbestos serve as one of the best classes of low-cost expendable
members of the friction couple for all-around performance.  At low energy
absorption rates, the temperature of the friction material, approximately
40 mils from the interface, may rise to 300°F; the interface itself is
hotter.  Most of the heat is removed from the interface by convection
and conduction.(2-10)  At high energy absorption rates, heat is generated
faster than it can be dissipated and the temperature at the sliding inter-
face reaches a point where chemical reactions occur rapidly.  Surface
temperatures up to 1600°F have been observed or calculated; the presence
of olivine in the wear debris confirms that such temperatures have been
reached.

      2.3.3.2   Physical and Chemical Changes in Linings During Use

                Figure 2-4 illustrates the heterogenous nature of a
typical friction material composed of the following ingredients:   phenolic
binder (30 volume percent), asbestos fiber (55 volume percent), and cashew
friction modifier (15 volume percent).
                As a result of the energy conversion at the stator-rotor
interface, the composition of the brake lining surface is altered.   At
low service temperatures, the phenolic resin and organic friction modi-
fier convert, on the surface, to compositions with slightly higher carbon/
oxygen ratios.  At somewhat higher use temperatures, the resin and or-
ganic friction modifier convert to carbon more readily, and this  in turn
oxidizes to carbon dioxide.  At the same time, the asbestos wears away
more rapidly because of the reduced binder strength and volume at the
surface.  Figure 2-5 is a photomicrograph of typical wear debris  collected
from Bendix Research Laboratories' dynamometer, operated at 600°F.   Asbestos
fibers are prevalent in several of the wear debris particles.  Figure 2-6
is a photograph of the improved wear debris collector designed and built
for friction and wear research.(2-11)  At still higher temperatures,  the
asbestos converts from its fibrous form to an olivine powder with little
or no reinforcing value.  Figure 2-7 shows the frictional-heat-affected
layer of lining which had experienced more than 10 successive stops from
100 mph without sufficient cooling between stops.(2-12)  (A large piece
of material is about to separate from this sliding interface - an example
of macroshear wear, described later.)

                When heat is generated at the sliding interface between
stator and rotor much faster than it can be dis-sipated, the temperature
rises and may reach a point where the lining or pad components decompose,
oxidize, or melt.  The stator material then wears  rapidly and the fric-
tion coefficient, y, may decrease.  This is fade.   Fade has been attri-
buted by some to evolution of gas at the sliding interface; on heating,
the gas expands and exerts a force on the lining or pad, tending to
push it away from the rotor. (2~ 13)  pa
-------
      <  Jfr*
       *•,« n5  *•
     i
«•  ^VlHt
  ci iniMr;  Jfc* .-^3r i?4
             Sf'"  ?V';
HEAT-AFFECTED LAYER
          i
                           FRICTION MODIFIER
   Figure 2-4 - Photomicrograph of Brake Lining Cross Section After
               8550 Miles of Test-Track Service
                                                   x 9,250
   Figure 2-5 - Electron Micrograph of Friction Material Wear Debris
              (Made  during 1966 studies) - 10,000 X
2-10

-------
    Figure 2-6 -
Close-up View of Bendix  Drag  Dynamometer Showing
Wear Debris Collector
                                                            Sliding
                                                            Surface
                                                              Heat-
                                                             Affected
                                                              Zone
                                                            Unchanged
                                                             Material
Figure 2-7 - Photomicrograph  of  Cross Section of Friction Material
             Test Specimen  After More Than 10 Successive Stops from
             100 mph on Bendix Full-Brake  Dynamometer
                                                                   2-11

-------
ho
                    PHYSICAL OR CHEMICAL CHANGE

                   CAST IRON MELTS
                   CaC03 (CALCITE) DECOMPOSES
                   CaC03 (ARAGONITE) DECOMPOSES
                   ASBESTOS PRODUCTS TRANSFORM
                     TO OLIVINE
                   ASBESTOS LOSES MORE WATER
                   IRON POWDER AND FIBERS
                     BEGIN OXIDIZING
                   GRAPHITE BEGINS OXIDIZING
                   ZINC MELTS
                   PHENOLIC RESINS CHAR
                   PHENOLIC RESINS OXIDIZE
                   AMORPHOUS CARBON BEGINS
                    OXIDIZING
                   ASBESTOS LOSES WATER
                   FRICTION DUSTS AND RUBBER CHAR
                   BRASS BEGINS OXIDIZING
                   ZINC BEGINS RAPID OXIDIZING
                   FRICTION DUSTS AND RUBBER
                    OXIDIZE
TEMPERATURE
op oc
2105 1150







787 419 	


700 372 	

500 260 ' 	
>440 >225 	
*-"/MO ^225

395 200 —












































































































1200- 	 1

	 1


	 »-

800 	





^


400- 	
	 ft








	



	




	



—


	
                                                                PHYSICAL OR CHEMICAL CHANGE
                                                                                         1200-
                                                     CASTIRONMELTS
                                                     PEARLITE BEGINS TRANSFORMING -
                                                     TO MARTENSITE
                                                     SEVERE SCALING BEGINS-
                                                     GRAPHITE BEGINS -
                                                     SPHEROIDIZING
                                                     VISIBLE, ADHERENT SURFACE •
                                                     OXIDE FORMS
                                                                                          400-
                                                                                                                                           200-
                                                                                                       -2000
                                                                                                       -1600
                                                                                                       -1200
                                                                                                       -800
                                                                                                                                                        -400
                                                                             °C
                                                                                                                                             °c
                             Figure  2-8 - Changes Occurring in  the
                                               Friction  Material as  the
                                               Temperature  Rises
                                                      Figure  2-9 - Changes  Occurring in  the
                                                                        Rotor  as the  Temperature
                                                                        Rises

-------
summarizes the physical and chemical changes which take place in the
friction material as the temperature rises.(2-14)  Figure 2-9 summarizes
the physical and chemical changes which take place in the cast-iron rotor
as the temperature rises.

      2.3.4   Brake Lining Wear Mechanisms and Generation of Emissions

      2.3.4.1   Types of Wear Mechanisms

                Emissions are generated by wear.  To the consumer, wear
is an economic consideration.  To the environmentalist, these emissions
are substances to be characterized and, if harmful, to be eliminated.
                From the basic friction material engineering standpoint,
wear resistance is inversely related to friction level and other desir-
able performance characteristics.  Linings with faster wear rate and
more frequent surface renewal generally have greater frictional sta-
bility.  --This circumstance is used to advantage in the development of
primary-type linings for duo-servo brakes, where, because of design,
the stability of frictional properties is of greater significance to
brake performance than is wear resistance; use of primary linings with
too much wear resistance results in poor fade resistance, less fric-
tional stability, and generally poor overall performance.

                Except in the case of primary linings, however, one of
the formulator's objectives must be to achieve the highest possible
level of wear resistance.  Contrary to the opinion of some, maximum
life does not require a friction material of maximum physical hardness.
What is desirable is a minimum wear rate in normal low-temperature use,
a moderately increased rate at elevated temperatures, and a return to
the original low-temperature wear rates after being subjected to ele-
vated temperatures.

                Total emissions generation may be defined as the sum total
of the losses associated with five basic types of wear.(2-15)

                •  abrasive wear,

                •  thermal wear,
                •  adhesive wear,

                •  fatigue wear, and
                •  macroshear wear

As shown in Table 2-2, there are several possible mechanisms for each
type of wear.

      2.3.4.1.1   Thermal Wear

                  Thermal wear encompasses a group of physical and chemi-
cal reactions in the course of which interatomic bonds are broken by ther-
mal energy.  These reactions include pyrolysis (thermal decomposition),
                                                                    2-13

-------
           Table 2-2 - Wear Mechanisms in Friction Materials
       THERMAL WEAR
         PYROLYSIS
         OXIDATION
         THERMOPARTICULATION
         MELTING
         EVAPORATION
         SUBLIMATION
         EXPLOSION
       ABRASIVE WEAR
         TWO-BODY
           ASPERITIES
           SCORING
           CRACK EDGES
           PIT EDGES
         THREE-BODY
           WEAR DEBRIS
           ROAD DUST
ADHESIVE WEAR
  ORGANIC MATERIAL ADHESION
    BINDER
    FRICTION DUST
    RUBBER
  INORGANIC MATERIAL ADHESION
    METAL PARTICLES
    ICE
FATIGUE WEAR
  THERMAL
    CYCLING
    SHOCK
  MECHANICAL
    REPEATED BRAKING
    DRUMS OUT OF ROUND
    DISCS OUT OF PARALLEL
                                   MACRO-SHEAR WEAR
                                     ACROSS THE PAD
                                     AT CORNERS AND EDGES
                                     THROUGH HEAT-AFFECTED LAYERS
oxidation, thermoparticulation, explosion, melting, evaporation, and
sublimation.  Their rates increase exponentially with temperature, and
in extreme cases they result in fade.
                  Pyrolysis probably occurs predominantly at the centers
of linings and pads and to a lesser extent at the corners and edges.
Oxidation, on the other hand, probably predominates at the corners and
edges and is less severe at the center.  Explosive reactions occur
under highly abusive braking conditions, where the rate of heat input
is so high that solids are converted to gases well beneath the surface;
because these gases are greater in volume than the solids they displace,
they create a pressure that ruptures the lining in an explosive manner.
Four such reactions are represented in Figure 2-10.
                  It might be thought that rapid thermal wear occurs only
at high soak temperatures.*  In fact, however, thermal wear probably
 Soak temperatures are temperatures measured during dynamometer or vehicle
 testing, using a thermocouple located in the friction material or in the
 rotor, generally at a distance of 20 to 50 mils from the sliding interface
2-14

-------
        FRICTION
        < MATERIAL
        SURFACE
                  FRICTIOIMAL HEAT
                         V FRICTION MATERIAL
       (T)  CaCO3 (s) -»-CaO (s) + CO2 (g) *
       @  CASHEW DUST (s) -»CO2 (g) + H2O (g) + C (s)

       (3)  ASBESTOS-*H2O (g) + OLIVINE (s) + ASBESTOS FIBRILS (s)

       (?)  PHENOLIC RESIN ^CO2 (g) + H2O (g) + C (s)
                                         (S): SOLID
                                         (G): GAS
   *THE BRASS CHIP CONDUCTS HEAT RAPIDLY INTO
    THE FRICTION-MATERIAL SURFACE.


            Figure 2-10 - Mechanism of Explosive Thermal Wear


occurs  at  appreciable rates at low soak temperatures as  well.   It has
been shown that  the materials in a sliding friction couple  contact each
other at the tops  of asperities on their surfaces.  There is  consider-
able evidence  to indicate that the temperature increase  at  these asperi-
                                                           f 9  1 fi  7 I  "
ties for low sliding speeds is represented by the equation^     » *-~-
T -
                             (gyvw/4aJ)[l/(k
where
       T is  the  "flash" temperature

      T  is  the  soak temperature

       g is  the  acceleration due to gravity

       y is  the  coefficient of friction

       v is  the  sliding velocity

       w is  the  load on the asperity
                                                                      2-15

-------
       a is the radius of the asperity junction

       J is the mechanical equivalent of heat

      k.. is the thermal conductivity of the disc

      k  is the thermal conductivity of the slider

Modifications of this equation have also been developed for high  sliding
speeds.  Experiments indicate that the flash temperature may be as high
as  1400°F  (760°C) if the soak temperature is 650°F  (343aC).  This flash
temperature is high enough to cause rapid localized pyrolysis of  the
organic compounds used in friction materials, as well as conversion of
fibrous asbestos to powdery olivine and transformation of pearlite to
martensite in the cast-iron mating surface.

      2.3.4.1.2   Abrasive Wear
                  Abrasive wear is of two types:  two-body wear (Fig-
ure 2-11)  and three-body wear (Figure 2-12).  Plowing by asperities on
the rotor  surface and plowing by edges in rough-machined, scored, cracked,
or  corroded (pitted) rotors are examples of two-body wear.  Grinding by
wear debris and by foreign particles such as sand, clay, mud, or  salt
in  the sliding interface is three-body wear.

                  Abrasive wear would be expected to increase with tem-
perature.  It increases also with the braking load and with the concen-
tration, size, and hardness of foreign particles.  It may be accompanied
by  negative fade.

                  Figure 2-13 is a Bendix scanning electron photomicro-
graph of a dynamometer-tested friction material showing the abrasive wear
tracks on  the surface.  Several adherent wear debris particles are
similar in size to the wear track widths.

      2.3.4.1.3   Adhesive Wear

                  Adhesive wear, illustrated in Figure 2-14, involves the
adhesion of organic and/or inorganic materials to the rotor and the sub-
sequent tearing or separation of these materials from the lining  or pad.

                  Organic constituents of friction materials include the
binder, friction modifiers and elastomeric compounds.  Inorganic  consti-
tuents include zinc powder, brass chips, and asbestos.  Little is known
about the  tendency of these materials to adhere to the cast iron used
in  today's drums and discs, though experience with hot elastomeric com-
pounds suggests that elastomers are very likely to stick.  Experiments
at  Bendix  Research Laboratories indicate that brass chips will alloy
with certain nonferrous rotor alloys.(2-18)  men thig occurs^ metal
is  transferred from the rotor to the lining, scoring the surface  of the
rotor and  in turn subjecting the lining to a high rate of two-body abra-
sive wear.
2-16

-------
        DIRECTION OF RELATIVE MOTION
                                       A DIRECTION OF
                                           NORMAL
                                            FORCE
ASPERITIES INTERACTING
 TO FORM WEAR DEBRIS
                 FRICTION MATERIAL
                                                        ROTOR

                                                        WEAR
                                                        DEBRIS
 Figure 2-11 - Mechanism of Two-Body Abrasive Wear
          DIRECTION OF RELATIVE MOTION
                                      DIRECTION OF
                                        NORMAL
                                         FORCE
                                                        ROTOR
                                                         WEAR
                                                        DEBRIS
Figure 2-12 - Mechanism of Three-Body Abrasive Wear
                                                         2-17

-------
 Figure 2-13 - Scanning Electron Photomicrograph Showing Abrasive Wear
 Tracks on Friction Material Surface and Adherent Wear Debris Particles
                      DIRECTION OF RELATIVE MOTION
     \ POINT OF ADHESION
ERECTION OF
  NORMAL
   FORCE
                             FRICTION MATERIAL
                Figure 2-14 - Mechanism of Adhesive Wear
2-18

-------
                  Adhesive wear probably increases with temperature,
braking load, and the concentration of adherent components in the friction
material.  It is also caused by the presence in the friction material
of metal particles capable of solution in or reaction with the rotor
alloy, increasing with the size and concentration of such particles.
Because this type of wear can cause stick-slip, it may be associated
with brake noise.
      2.3.4.1.4   Fatigue Wear
                  Fatigue wear (Figure 2-15) is most commonly observed
in metal bearings.  However, it may also be experienced by organic fric-
tion materials, occurring in two forms, thermal and mechanical.

                  Thermal fatigue is caused by repeated heating and
cooling.  Such repeated temperature changes impose cyclic stresses on
the surface material, which heats and cools more rapidly than the bulk
material and thus expands and contracts to a greater extent.  Because
of their low thermal conductivities, the thermal gradients and resultant
thermal stresses in organic friction materials may be higher than those
in metals.
                  Thermal-shock cracking may be thought of as a special
case of thermal fatigue, occurring as a result of a single abusive
loading.
                  Mechanical fatigue is caused by repeated mechanical
stressing.  Because of the frequency of brake use, friction materials
are subjected repeatedly to both compression and shear forces.  Addi-
tional stresses are also applied repeatedly if drums are out-of-round,
if discs are out-of-parallel, or if rotor thickness is not uniform.
                  Figure 2-13 shows the initiation of fatigue wear around
the large cashew particle.  This material swells when heated and thus
the surface wears.  After cooling, the particle contracts, cracks, and
pulls away from the edges.  When the particle is completely loose, it
can fall out.

      2.3.4.1.5   Macroshear Wear

                  Three types of material removal fall in the category of
macroshear wear, which is illustrated in Figure 2-16.

                  A fracture, in shear, may occur across the entire  brake
pad under extremely heavy loading, especially if the friction material has
previously been weakened by heat.   This is a sudden rather than a gradual
type of wear.

                  Fracture at the  edges and corners of a piece of friction
material is another type of macroshear wear.   Oxidation of organic com-
ponents weakens the friction material at  these locations.
                                                                    2-19

-------
                         FRICTION MATERIAL
                 Figure 2-15  -  Mechanism  of  Fatigue Wear
   GENERALIZED
 FAILURE THROUGH
  HEAT-AFFECTED
      ZONE
                       DIRECTION OF RELATIVE MOTION
DIRECTION OF\
  NORMAL
           \
           \
   LOCALIZED
FAILURE AT EDGE
 WEAKENED BY
   OXIDATION
               Figure 2-16 - Mechanism of Macroshear Wear
2-20

-------
                  Fracture at the edges and corners of a piece of fric-
tion material is another type of macroshear wear.  Oxidation of organic
components weakens the friction material at these locations.

                  A third type of macroshear wear can occur when a fric-
tion material such as that shown in Figure 2-15 is subjected to heavy
loading following thermal abuse.  The heat-affected layer in the material
pictured is about 100 mils deep, and from this layer organic material
has been removed by pyrolysis.  If sufficiently weakened, such a layer
can be sheared away by a single, heavy brake application.
                  Whatever the mechanism, macroshear wear is promoted by
nonuniform loading and by oxidation and thermal degradation of the
binder.  It is most likely to occur at elevated temperatures and under
severe braking conditions.  Its end products are typically large frag-
ments of friction material that leave the surface rough.   These frag-
ments subject the remaining friction material to plowing or abrasive
wear, and while they are present in the interface, friction behaviour
will be erratic.

      2.3.4.2   Predominant Wear Mechanisms

                The predominant wear or emissions-generation mechanisms
may be summarized simply (Figure 2-17):(2-19)

                •  Below 450°F:
                       Abrasive and adhesive wear.

                •  Above 450°F:
                       Thermal wear.

Figure 2-18 illustrates the wear loss of three different  kinds of fric-
tion materials as a function of temperature, illustrating these predomi-
nant wear mechanisms.

      2.3.4.3   Wear Equation
                Recent work at Bendix Research Laboratories has indicated
that each friction material wears according to a universal wear equa-
tion.(2-20)


                        AW = k • pa • Vb •  tC
or
            log (AW) = log k + a log P + b log V + c log t
                                                                     2-21

-------
                  0.09
                  0.08-
                  0.06
             II
                  0.05-
0.04-
                   0.03
                                     /A
                                    /P
                                                  THERMAL WEAR
                                                 - PREDOMINATES
                    BRASIVE WEAR
                    PREDOMINATES
                                        300        400
                                     ISOTHERMAL TEMPERATURE
                                                                    600 °F
     Figure 2-17  - Predominant Wear Mechanisms of Friction Materials
                 100
                          200
                                   300       400       500

                                 ISOTHERMAL TEST TEMPERATURE (°F)
                                            600
   Figure  2-18 -  Variation of Friction Material Wear with Temperature
2-22

-------
where

      AW is the weight lost

       k is the wear factor

       p is the load

       V is the sliding velocity

       t is the time of sliding, and

      a,b,c are constants characteristic of a given friction couple.

                When further developed, this equation will be useful  for
predicting wear (and emissions) under various driving conditions.

      2.3.5   Emissions of Particulate and Gaseous Emissions

      2.3.5.1   Drum Brakes
                Gaseous decomposition products in drum brakes are  emitted
from two areas:
                •  The space between the rotating drum and the stationary
                   backing plate.
                •  The small holes in the backing plate itself (e.g.,
                   clearance holes, brake adjusting slot,  etc.)

                Particulates are emitted from the same two areas,  although
only small particulates would come through the holes in the backing plate.
In drum brakes, some particles are not emitted but remain in the rotating
drum.  It is expected that some of these particles would eventually be
emitted through the space between the rotating drum and stationary back-
ing plate.  Also, some large particles would be "ground up" and emitted
as a number of smaller particles if they are trapped between the friction
material and drum on subsequent braking or if they are trapped between
the rotating drum and stationary backing plate.  If the brake shoes are
of riveted construction, then some particles can be trapped in the rivet
holes and thus retained in the brake.

                If convective cooling of drum brakes is improved in the
future, as is desirable for safer operation and longer driving life,  it
is likely that fewer particles will remain trapped.  The particles
emitted, however, will probably be larger, as they will be subjected
to grinding action for shorter periods of time.

      2.3.5.2   Disc Brakes

                As the disc brake is essentially an open braking system,
it is expected that all particulate and gaseous decomposition products
                                                                    2-23

-------
will be emitted.  However, a small amount of particulates collect  in  the
rivet holes of riveted disc brake pads and on some areas of the caliper.

      2.3.5.3   Clutches
                In the dry clutches commonly in use on "stick-shift"  cars,
there are very few openings for gases and particles to escape.  The two
main areas are:
                •  The area around the clutch fork, which generally has a
                   rubber boot on it for protection of the clutch  from
                   road spray, sand, etc.
                •  A small opening at the lower front of the clutch to
                   drain any oil, water, etc., which may get into  the
                   clutch.

Because of the construction, many particulates remain in the clutch
housing.

      2.3.6   Distribution and Changes in Brake and Clutch Emissions

              Entrapped gases and pyrolysis gases released during braking
or clutch slipping will be hot enough to mix rapidly with the surrounding
air and become part of the air wake of the car.  The higher molecular
weight vapors will condense and eventually settle to the ground.   The low
molecular weight gases will disperse as part of the local atmosphere.
Some of the condensible vapors may, of course, settle on small, air-borne
dust particles and could be carried into the respiratory system as part
of the breathing air.

              The particle emissions will disperse in different ways depend-
ing on their size, shape, and density.  Submicrometer-size particles, re-
gardless of shape, will ordinarily remain air-borne until they are
scrubbed out by rainfall or some other separating action.  In effect they
become a long-time part of the atmosphere.

              Spherical particles in the 1.0 ym to 10 ym diameter range
will settle, under gravity and in still air, at velocities from 12 to
1000 cm/hr, according to Stokes1 law.  Irregularly shaped particles of
similar size and in turbulent air will settle at much slower velocities
and could remain air-borne for hours or days.  These particles cause the
greatest aggravation in the human respiratory system because they  collect
in the tracheo-bronchial regions and, to some extent, in the alveoli.

              Particles from 20 ym to 100 ym in diameter will settle as
part of the dust trail left by the car or will collect with any larger
particles in mechanical traps in the car.  Eventually these larger-size
particles will fall or be shaken out of the car and become part of the
road dust.
 2-24

-------
2.4   REFERENCES
      (2-1)   J. Lynch, "Brake Lining Decomposition Products," J. Air
              Poll. Control Assoc., 18_, No. 12, 824 (1968).
      (2-2)   S. Spiel, Johns-Mansville Research and Engineering, private
              communication, 1971

      (2-3)   Private Communication, 1972.
      (2-4)   J. Moran, Environmental Protection Agency, private communica-
              tion, 1972.
      (2-5)   B. W. Klein, "Semi-Metallic Outer Pads for Disc Brakes,
              "Bendix Technical Journal", _2, (No. 3), 109-113 (Autumn 1969).

      (2-6)   A. A. Hodgson, "Fibrous Silicates, "Lecture Series No. 4,
              Royal Institute of Chemistry, London, England, 1965.

      (2-7)   M. G. Jacko, W. M. Spurgeon, R. M. Rusnak, and S. B. Catalano,
              "Thermal Stability and Fade Characteristics of Friction
              Materials," _SAE Transactions, 77, 1474 (1969).
      (2-8)   11. G. Jacko, "Thermal Analysis of Friction Materials,"
              presented at the National Meeting of The American Chemical
              Society, San Francisco, Calif., April 1968; also S. Porter
              (ed.), Analytical Colorimetry, Plenum Press, N.Y., 1968.

      (2-9)   F. W. Aldrich and M. G. Jacko, "Organic Friction Materials,"
              Bendix Technical Journal,  (No. 1), 42-54  (Spring 1969.)

      (2-10)  R. M. Rusnak, H. W. Schwartz, and W. P. Coleman, " A Com-
              parison by Thermal Analysis of R.otor Alloys for Automobile
              Disc Brakes," SAE Paper 700137, January 1970.
      (2-11)  A. R. Spencer, W. 11. Spurgeon, and J. L. Winge, "Four Tests
              for Consistency of Automotive Brake Linings," SAE Paper
              660412, presented at the Mid-year Meeting, Detroit, Michigan,
              June 1966.
      (2-12)  M. G. Jacko and R. M. Rusnak, "Physical Properties of Disc
              Pads and Rotors Dynamometers.  Tested at 100 mph," Bendix
              Progress Report, May 1969.
      (2-13)  J. M. Herring, "Mechanisms of Brake Fade in Organic Brake
              Linings, "SAE Paper 670146, presented at the SAE Annual
              Meeting, Detroit, Michigan, January 1967.

      (2-14)  W. M. Spurgeon, "Increasing the Service Life of Friction
              Materials," Bendix Progress Report, June 1969.

      (2-15)  W. M. Spurgeon and A. R. Spencer, "Reliability and Durability
              of Automative Friction Materials," Bendix Technical Journal,
              2, (No. 3), 57-66 (Autumn 1969).                     "   ~~
                                                                    2-25

-------
       (2-16)   F.  P.  Bowden and D.  Tabor,  The Friction and Lubrication of
               Solids,  Clarendon Press,  Oxford,  England,  p.  53, 1950.

       (2-17)   E.  Rablnowicz,  Friction and Wear  of Materials,  John Wiley
               and Sons,  New York,  p.  89,  1965.

       (2-18)   S.  K.  Rhee,  J.  L.  Turak,  and W. M.  Spurgeon,  "An Inertial
               Dynamometer  Evaluation  of Three Alloys  for Automotive
               Brake  Drums," SAE Paper 700138, presented  at  the SAE
               Automotive Engineering  Congress,  Detroit,  Michigan,
               January  1970.

       (2-19)   S.  K.  Rhee,  "Influence  of Rotor Metallurgy on the Wear of
               Friction Materials in Automotive  Brakes,"  SAE Paper  710247,
               presented  at the SAE Automotive Engineering Congress,
               January  1971.

       (2-20)   S.  K.  Rhee,  "Wear Equation  for Polymers  Sliding Against
               Metal  Surfaces," Journal  of  Wear. 16^ p.  431 (1970).
2-26

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                               SECTION 3

                         MATERIALS SELECTIONS
3.1   BACKGROUND
      Friction materials and rotor materials vary in composition accord-
ing to their source.  There are original equipment manufacturers (OEM)
and aftermarket (AM) friction materials in addition to foreign friction
materials; there are wide variations according to use and origin.
Friction materials are the expendable item of the friction pair.  Con-
sequently, friction materials are usually replaced two to five times
during a vehicle's life-time, while rotor materials are seldom replaced.
However, rotor materials are occasionally turned, that is, the rubbing
surface is machined so that fresh metal is exposed as a new rubbing
surface.
     The asbestos content of any particular friction material is not
known, as this is information proprietary to the manufacturer.  With
the use of modern analytical tools, it is possible to estimate the
asbestos content to the nearest + 2 weight percent.  Thermogravimetric
analysis yields the organic/inorganic ratio as well as the inorganic
residue remaining above 800°C.  X-ray diffraction indicates the inorganics,
other than asbestos, and their relative amounts.

3.2   MATERIALS SELECTIONS FOR PROGRAM

     3.2.1   Friction Material Selections
             A completely balanced program would contain friction
materials comparable to most of those in normal customer usage.  If a
large number of tests can be run, it is easy to fulfill that requirement.
If only a small number of tests can be run, the selections are less
representative and much more critical.  The objective of the program
was to obtain brake emissions from disc and drum friction materials,
OEM and AM friction materials, friction materials from several different
manufacturers, both new and used friction materials, and repeats of at
least one axle set of friction materials.  This was a considerable task
since only a limited number of tests were funded.  Three vehicle tests
were planned in such a way as to accomplish these goals.  It is believed
that the friction materials used are representative of a high proportion
of those on the road today.

             A custom-size vehicle was chosen as a median between the
compacts and luxury-size vehicles prevalent in the country.  The vehicle
was equipped with the front disc pads and the rear drum primary and
secondary lining combinations,  listed in Table 3-1.  Each of the front
axle and rear axle friction materials was produced by different manu-
                                                                     3-1

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Table 3-1 - Vehicle Configurations and Lining Selections
Test
Number
1
2
3
Description
Original
Equipment
Aftermarket
Equipment
Aftermarket
Equipment
Lining
Selections
Front Disc: TP-1003
Drum Rear:
Primary: 4641
Secondary: H3133
Front Disc: R-4528-4-FF
Drum Rear:
Used OEM Combination
from Test 1.
Front Disc: WB-60-FF
Drum Rear:
Primary: ABB-249-FF-PRI
Secondary: ABB-250-FF-SEC
Manufacturers
Panelyte Division
Thiokol Corporation
Friction Materials Division
Bendix Corporation
Raysbestos-Manhattan Corp.
Friction Materials Division
Bendix Corporation
Worldbestos Division
Firestone Tire & Rubber Co.
ABEX Division
American Brakeblock Corp.
Remarks
• Class A type
organic disc pads.
• No metallic chips in
any linings
• Discs were not turned
• Drums were not turned
• Disc pads and secondaries
contained brass chips.
• Disc were turned.
• Drums were turned.

-------
facturers.  The vehicle was received new with less than 5 miles on the
odometer.  Prior to vehicle test 1, all rotors were adjusted to their
OEM condition and unused disc pads and linings were installed to replace
those with partial use.  Vehicle test 1 was made with the OEM test con-
figuration.
             Vehicle test 2 was a simulation of a typical consumer prac-
tice: the replacement of the front axle friction materials only (Table
3-2).  The discs and drums were not turned.  The rear lining combination
was considered "a repeat."  The rear lining combination was also consider-
ed as an extended test of "used" friction materials to ascertain the
nature of the brake emissions with extended use against their original
rotor.  The front disc pads were purchased as aftermarket friction
materials sold in the Detroit area.  The manufacturer was among the
larger AM manufacturers.

            Table 3-2 - Surface Roughness Measurements on
                        Turned Discs and Drums for Vehicle Test 3

Specification
As Machined
Front Brakes
Right
(Shrouded)
15-80 micro
28-30
Left
(Normal )
inches
27-32
Rear Brakes
Right
(Shrouded)
60-120 micr
90-95
Left
(Normal)
oinches
75-85
             Vehicle test 3 was a simulation of a second consumer prac-
tice: the replacement of friction materials on both axles in addition
to turned discs and drums (Table 3-1).  The final conditions of the
rotors and drums are listed in Table 3-2.  The front and rear axle fric-
tion materials were produced by manufacturers different from those
for the friction materials used in any other vehicle tests, and both
manufacturers were among the larger AM manufacturers.
             Briefly summarizing the three vehicle tests, five different
friction material manufacturers are represented.  Both OEM and AM disc
pads and drum linings were selected.  The OEM manufacturers represented
supply a large part of the OEM market and the AM manufacturers repre-
sented supply a large part of the aftermarket.  All  AM friction materials
were purchased over-the-counter at various locations in the Detroit area.

       3.2.2  Contents of the Friction Materials

              The asbestos content of the friction materials used was
determined by the analytical methods mentioned earlier.  The percent of
asbestos estimated for each material is listed in Table 3-3.  This infor-
mation was obtained in order to ascertain, in later stages of the program
whether there is any correlation between the asbestos content of a fric-  '
tion material and the asbestos content of its wear debris.
                                                                    3-3

-------
u>
                                               Table 3-3 - Estimated Asbestos Content

Number
No. 1







No. 2


No. 3




Description
ORIGINAL
EQUIPMENT






AFTERMARKET


AFTERMARKET




Lining
Identifications
Front Disc: TP-1003
Inner
Outer
Drum Rear:
Primary: 4641 (EBEF)
Secondary: H3133 (DUGF)
Clutch: US 969
(Used in all tests)
Front Disc: RM R4528-FF
Rear Drum: Used OEM Combination
4641 H3133
Front Disc: WB 60-FF
Rear Drum:
Primary: ABB-249-FF-PRI
Secondary: ABB-250-FF-SEC
Estimated Wt %
Total
Residue*

60
61

68
59

66
63


71

63
66
Olivine

55
56

63
55

30
60


52

63
62
Other**

5
5

2
4

36
3


19

_
4
Asbestos

64
65

76
64

35
70


60

74
73
                      *By thermogravimetric analysis at 900°C.
                     **Estimated from x-ray diffraction.

-------
                              SECTION 4

                     VEHICLE AND INSTRUMENTATION
4.1   VEHICLE DESCRIPTION

      In this program, a passenger car of medium weight (4850 Ibs
test weight), produced in high volume was selected.  It was equipped
with a three-speed manual transmission, ventilated cast-iron disc
brakes on the front, and cast-iron drum brakes on the rear.  This
vehicle was selected in order that the emissions from clutches and
from disc and drum brakes could be tested simultaneously on a vehicle
size representing a large percentage of the present vehicle popula-•
tion.  A detailed vehicle description is given in Table 4-1.

                  Table 4-1  - Test  Vehicle Description
      General Description

         1971 two-door hardtop
         V-8 engine
         Three-speed standard-shift transmission

         Power brakes (disc front/drum rear)

         Power steering

         Air conditioning

      Vehicle Weight
         Curb weight:  Approximately 4000 Ibs
         Test weight:  4850 Ibs  (with driver and passenger)

      Tires
         H 78-15

      Brakes
                                              2
         Front Disc:  Inner Pad Area:   8.5 in
                                              2
                      Outer Pad Area:  11.2 in

         Rear Drum:   11 inch diameter by 2-1/2 inch
                                                     2
                      Primary Lining Area:    21.0 in
                                                     2
                      Secondary Lining Area:  27.3 in
                                                                     4-1

-------
 4.2   BRAKE TEST INSTRUMENTATION
       The vehicle was instrumented with standard brake test instrumentation
 (Figure 4-1):
       Brake pedal application counter
       Front and rear brake hydraulic pressure gages
       U-tube decelerometer
       Brake lining temperature pyrometers for each wheel (thermocouples
       were placed in one lining of each wheel in accordance with the SAE
       specification J-843
       Twelve-position thermocouple switch and pyrometer to monitor gas
       trap and particle trap collector temperatures
4-2

-------
           BRAKE
         HYDRAULIC
         PRESSURE
           GAGES
               BRAKE PEDAL
               APPLICATION
                 COUNTER
                                                                   BRAKE
                                                                   LINING
                                                                 PYROMETERS
   12-PLACE
THERMOCOUPLE
   SWITCH
Figure  4-1 - Vehicle Instrumentation for  Friction Material Testing
                                                                       4-3

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                               SECTION 5

                     EMISSIONS COLLECTION SYSTEMS
5.1   OPERATION REQUIREMENTS

      5.1.1   Operation and Design Criteria

              Only 100 percent collection can assure a reliable measure
of the total emissions from the clutch, drum and disc brakes.   The com-
posite nature of the emissions, including gases, volatile liquids, and
solid particles, makes it impossible to obtain a representative sample on
anything less than a 100 percent collection.  The first requirement for
the emissions collector, then, was that it collect all the particle and
vapor emissions from the clutch and brakes.   It also had to store these
emissions during a complete test cycle without changing them.

              Another important requirement for the emissions  collector
was that it should prevent intrusion of contaminants, or at least of
contaminants that could not be positively distinguished from brake emis-
sions.  Oxygen and nitrogen had to be excluded from this restriction since
operating in an inert gas atmosphere would seriously change the character
of the emissions.
              The collection systemshould not, of course, significantly
change the ordinary operating conditions of the clutch or brakes.  This
means it should not materially change the heat flow and that the air flow
rate through clutch and brake chambers had to be similar to that under
ordinary operating conditions.  The flow pattern did not need  to be iden-
tical since this would not affect  the generation of emissions at low tem-
peratures, but only the way in which they were carried out of  the brake
and clutch chambers.
              The front disc collector had to be capable of operating at
brake temperatures to 650°F (340°C) with the sealing surface operating
up to 400°F (205°C).  The rear drum collector had to be capable of operat-
ing at brake temperatures to 500°F (260°C),  the sealing surface operating
to approximately 350°F (177°C).  The clutch collector had to be capable
of operating at temperatures to 250°F (121°C).

              Finally, the collection system had to permit easy separation
and analysis of the different types of emission - large and small parti-
cles down to 0.2 pm size, condensable vapors, and volatile gases.  If
expensive preliminary separations had to be carried out in the laboratory,
an already difficult and time-consuming analysis would become  even more
extended and costly.
                                                                     5-1

-------
              The major requirements for the emissions sample collection
system may be summed up, therefore, as follows:
              o  Collect all particulate and gaseous emissions,

              «  Store collected emissions unchanged,

              o  Prevent intrusion of contaminants,
              o  Maintain ordinary braking and clutching conditions,

              o  Be operable at high temperatures, and
              *  Permit easy separation and analysis of emissions.

      5.1.2   Emission Expected
              Appendix A shows a series of wear debris calculations which
included the chemical composition and the amounts of wear debris expected.
This information was necessary to insure proper sizing of the emission
collection hardware.

5.2   OVERALL DESIGN CONCEPT

      5.2.1   Air Flow of a Typical Collection System
              The basic design concept of each brake emissions collection
system is shown in Figure 5-1.  Air from inside the vehicle was pulled
into a bed containing Drierite and calcium oxide pellets which remove
water and carbon dioxide from the air.  After passing through the bed,
the air passed through a filter to remove all particles larger than
0.2 ym (8 x 10~6 inches).  The filtered air was then routed to the sealed
brake or clutch assembly through clean Teflon tubing.  The air stream,
along with wear particles and gases, then passed out of the brake or
clutch through Teflon tubing surrounded by heating coils to keep the gases
at 200°F (93°C) in order to avoid condensation.  This stream passed
through two filters to remove the airborne particles and preserve them
for analysis.  The stream then passed through three cold traps in order
to condense and trap the gases evolved during braking and preserve them
for analysis.  Finally, the air stream passed through a flowmeter, the
vacuum manifold, and an air pump run by the vehicle engine, finally being
expelled to the atmosphere.

              Figure 5-2 shows the engine-driven air-pump installation
under the hood. The pump was run by a belt attached to an added pulley
attached to the  drive  shaft of the alternator.  Thus the air pump had
two modes of operation:

              9  During engine idle, the pump ran at a low
                 fixed speed.

              •  During vehicle operation, the pump ran at
                 a speed proportional to the engine speed.
5-2

-------
          BRAKE
         ASSEMBLY
                                INLET AIR
                                FILTER
                                     DRIER
              CARRIER
              " AIR
                         0.2 ju ,
                           'QAO.Q.QA!
                      PARTICLE
                      FILTERS

                     HEATER COILS'
•utra
    i—R)
:TER  VACUUM  V  X
    MANIFOLD  I    |
                   9
                                 AIR PUMP
     GAS
    COLLECTION
     SYSTEM
                   Figure 5-1 - Schematic Diagram for Air Flow of Typical Particulate
                           and Gas Emission Collection System
U1

OJ

-------
T
--
                          TUBE CONNECTION TO

                           VACUUM MANIFOLD
                                    Figure  5-2 - Air Pump  Installation in Engine Compartment

-------
      5.2.2   Collection Systems Used

              Collection systems such as those described above were at-
tched to the following:  right front disc brake,  right rear drum brake,
and the clutch.  The left front and left rear brakes were not modified
in any way but were monitored to insure that the wear on the right side
was not changed significantly by the collectors.
              Figure 5-3 shows, mounted in the front seat of the test
vehicle, the front-brake inlet air filter and gas collection system, the
clutch gas collection system, and the twelve-position thermocouple switch
and pyrometer used to monitor gas and filter trap temperatures.  Fig-
ure 5-4 shows, as mounted in the rear seat of the test vehicle, the
rear-brake air filter and gas collection system, the clutch air filter,
and the electrical system.

      5.2.3   Electrical System
              The electrical system mounted in the rear seat consisted
of two batteries, one inverter, and two variable transformers, and was
used to supply AC voltage to the heating coils.
              Figure 5-5 shows the schematic for the electrical system.
              The inverter was capable of changing 12-volt DC power to
60-Hz, 120-volt power with an output of 400 watts continuously. Two extra
batteries were installed to provide sufficient electrical capacity for 10
hours of testing.  The inverter was separated by relays from the batteries
in order that peak voltages occurring during vehicle start up did not
damage the inverter.  This system consisted of power and latching relays
and a pushbutton switch.  After the vehicle was started, the pushbutton
switch was used to energize the latching relay which in turn energized
the power relay, providing DC power to the inverter.  When the vehicle
was shut down for any reason, the power to the latching relay was removed
and thus the power relay was also de-energized.  The AC output was regu-
lated to the heater through use of two variable transformers thus allowing
temperature adjustment.  The batteries were recharged each night in order
to provide sufficient power for the following day.

5.3   PARTICULATE FILTERS

      5.3.1   Filter Holders

              Two Gelman 47 mm filter holders joined in series were used
for the collection of airborne particulates.  These holders were sealed
with 0-rings, fabricated from stainless steel for protection against
corrosion, and loaded with standard 47 mm diameter filters.  Nuclepore
filters were used.  These filters were made from a smooth film of poly-
carbonate plastic with a number of circular pores through them.  The
pores did not restrict the flow of gases significantly as particle col-
lection proceeded.  The filter holders were heated by tape heaters wound
                                                                    5-5

-------
                                                      CLUTCH GAS
                                                   COLLECTION SYSTEM
      12 PLACE
THERMOCOUPLE SWITCH
    GAS COLLECTION
        SYSTEM
    HOLD-DOWN STRAP
     FRONT BRAKE GAS
    COLLECTION SYSTEM
    THERMOCOUPLE
      JUNCTIONS
    FRONT BRAKE INLET AIR
      DRIER AND FILTER
         Figure 5-3 -  Vehicle  Instrumentation  (Front Seat  Area)
5-6

-------
                                                    DC TO AC
                                                VOLTAGE INVERTER
                                                                VARIAC TO CONTROL
                                                               VOLTAGE TO HEATERS li
  REAR BRAKE
GAS COLLECTION
   SYSTEM
                                                       CLUTCH INLET
                                                    AIR DRIER AND FILTER
                    I  >-
                    REAR BRAKE
                     INLET AIR
                  DRIER AND FILTER
           Figure  5-4 - Vehicle Instrumentation (Rear  Seat Area)
                                                                             5-7

-------
                          VARIABLE
                        TRANSFORMER
Ln
00
                                        CLUTCH PARTICIPATE
                                        TRAP & LINE HEATERS
                                                            VEHICLE
                                                            BATTERY
                                                            (12VDC)
                                           REGULATOR
                 VARIABLE
               TRANSFORMER
                        AC
                      OUTPUT
                                     FRONT BRAKE PARTICULATE
                                        TRAP & LINE HEATERS
                                      REAR BRAKE PARTICULATE-
                                        TRAP & LINE HEATERS
  DC/AC
INVERTER
DC INPUT
                                                         1
                                                                                                             PUSHBUTTON
                                                                                                               SWITCH
n
di
o>
                                  Figure 5-5 - Electrical Schematic for Particulate Trap  and
                                                Transfer Line Heaters

-------
around the outside and controlled by a variable transformer within the
test vehicle.  The same configuration was used in all three collectors
(front brake, rear brake, and clutch).

      5.3.2   Filter Flow Characteristics

              At the beginning of the program, no data were available
for the flow characteristics for any type of filter when loaded with
brake wear debris.  Consequently a series of simple tests was performed;
the results are included as Appendix B.  The following results were
noteworthy:
              «  The pressure drop change across an 8.Op
                 Nuclepore filter loaded with up to 1.0
                 gram of wear debris was not high enough
                 to present problems in the program.

              •  Wear debris was easily removed from Nuclepore
                 membranes such that no significant error was
                 introduced when debris from several membranes
                 was comb ined.

5.4   GAS COLLECTION SYSTEMS

      5.4.1   Design and Fabrication of Traps
              To withstand handling and road shocks, it was deemed neces-
sary to design and build rugged gas traps for both condensable and non-
condensable gases.
              Figures 5-6 shows the schematic for the condensable-gas
trap.  The body of the trap^nd the tubing were made of stainless steel.
The top was threaded so that it seated against an 0-ring to provide a
vacuum-tight seal.

              Figure 5-7 shows the schematic for the noncondensable-gas
.traps.  The trap was designed so that it could be filled with granular
activated charcoal.  The charcoal was held 3/8 inch above the bottom of
the.trap by a stainless steel screen.  This allowed a small volume for
the gases to permeate toward the outside walls before they were absorbed
on the charcoal surfaces or passed through the charcoal bed to the exit
port.

              Figure 5-8 shows the schematic of the activated-charcoal
trap top and the plug used to fill the trap once the top had been threaded
on.  An 0-ring against a 45-degree bevel provided a vacuum seal.

              Figure 5-9 shows the complete gasi trap.   Figure 5-10 shows
an exploded view of the trap.
                                                                    5-9

-------
  t
  1"
1
,   FRONT        £          I

I                   '         J
I*	! 5/8"	»..*— 1"	•]
          1/2"

                  ro.D.
                                  BACK
                                   :;  1/8-
                                   ; ;  3/8-
                                   DETAIL "A"
                                    . 304 S.S.
                                     SEAMLESS TUBING
                                     1"O.D. 13 GA.

                                 1/4" O.D.S.S. TUBING
                                   •WELD-AIRTIGHT
                 0.810" I.D.
           (0.095 WALL THICKNESS)
                                                                   45°
                                                                    f      0.070"
                  i
                                                                             t
            PARKER
            SIZE 2-019
            CLASS AN
            O-RING
                                                              DETAIL "A"
MATERIAL  316 STAINLESS
               STEEL
                     Figure  5-6 - Condensable-Gas  Trap
5-10

-------
                                              MATERIAL: STAINLESS STEEL

t
1"
1
FRONT
1 3/4"
il
2 1/4" DIA. -~ 	 — v

I
4
304 S. S. TUBING 	
2" O.D. 11GA.
1/4" O.D. _^,
S.S. TUBING


L
3/8"
1
1



ifr

.A


2" O.D.
1.760" I.D.
»•
BACK
) , DETAIL "A"
I
S.S.
/SCREEN
I '

t
1/8"
1/8"
3/8"
a f^— 0.10"
4/4 1
1 IT
PARKER
088(r SIZE 2-031
' ' 1.749" I.D.
DETAIL "A"
                                                                 0.070"
    Figure 5-7 - Activated-Charcoal Gas Trap - Sectional View
                                                          1/2"-20 THRU TOP
                1/8" WIDE x 3/32" DEEP SLOT
1/8"
         1/2"
               1/2"
                          -PARKER
                           SIZE 2-014
                         , 0.070"
                                              TOP
                          -1/2" - 20 THREAD
              PLUG
        Figure 5-8 -  Activated-Charcoal Gas  Trap  - Top View
                                                                          5-11

-------
                Figure 5-9 - Activated Charcoal Gas-Trap
5-12

-------
                                                                    FACE FOR
                                                                   O-RINGSEAL
                   PLUG FOR
               ADDING ACTIVATED
                   CHARCOAL
                                  Figure 5-10 - Exploded View of  Activated Charcoal Gas-Trap
I
I—"
U)

-------
      5.4.2   Operation
              The gas traps were connected in series such that  the gases
flowed through the condensable-gas trap first and then through  two
noncondensable-gas traps containing activated charcoal.  Valves were  in-
stalled at the inlet and exit of each trap.  The traps were kept  in a
custom-made metal box lined with styrofoam, 1-1/2 inches thick, as shown
in Figure 5-11.
              The three gas traps were held at approximately -70°C (-95°F)
with solid carbon dioxide.  For the disc brake collector, which had higher
gas flow rates, a 2-foot length of 1/4-inch OD tubing was added,before
the condensable gas trap.  This was found necessary to prechill the gases,
or otherwise no condensation would occur in the first trap.

5.5   DISC BRAKE COLLECTOR

      5.5.1   Shroud Design and Construction

              The brake emissions collector for the right front disc
brake consisted of a sheet-metal duct, or shroud, completely covering
the caliper and disc, and an emission storage unit consisting of  particle
filters and gas traps.  The shroud is shown in Figure 5-12.  It served
as a collector and duct to carry the gaseous emissions into the delivery
tube to the  gaseous-emission  storage unit.

              Figure 5-13(a) and 5-13(b) show the 2 views of major sheet-
metal portions of the disc brake collector (parts were stainless  steel
to avoid corrosion) and Figure 5-14 shows the entire collector system
with the disc brake.

              Front and rear views of the collector system, as mounted
on the vehicle, are shown in Figures 5-15 and 5-16.

      5.5.2   Rotating Seal

      5.5.2.1   Initial Design and Problems

                The original design of the rubbing seal for the disc brake
shroud was a face seal of Teflon (Figure 5-17).  Problems arose with  this
design because of difficulty in realigning the seal after dismantling the
shroud for maintenance.  When the collector was opened for inspection and
then resealed, the out-board shield was not relocated in the exact same
position each time.  The  out-board face was usually slightly cocked in
a different manner each time.

                The out-board face held the rotating seal.  A 1-degree
shift of the face cause a 0.060-inch deflection at the groove where the
Teflon was sealed.  A deflection greater than 0.020 inch was found too
great for the seal's Teflon 0-ring to make up and consequently nonrepre-
ducible sealing and leaking occurred.
5-14

-------

STYROFOAM
VALVES TO
SEAL TRAPS
               METAL
                BOX
NON-CONDENSABLE
   GAS TRAPS
                              AIR OUT
                                                                                          CONDENSABLE
                                                                                            GAS TRAP
                                                                                         GASES & AIR IN
                                                                                                  623-71
                               Figure  5-11 - Gas  Collection  System

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                                             TIRE
                   BRAKE
                     PAD
  BEARING
   DUST
    CAP
                                        THERMOCOUPLE
                                          (FOR BRAKE
                                         TEMPERATURE)
                                                 SPLASH SHI ELD
                                                  (MODIFIED)
        ROTATING
         SEAL
                                                                     TO
                                                                   EMISSION
                                                               "-  STORAGE
                                                                     UNIT
             Figure 5-12  - Sectional View - Disc Brake Shroud
5-16

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                                                                                       INBOARD RING AND
                                                                                         CALIPER COVER
                                                                                                            MODIFIED DUST
                                                                                                               SHIELD
                        OUTBOARD
                         SHIELD
CALIPER TOP
  COVER
                                                                                                                     656-7)
                            Figure 5-13(a) - Major Portions of Disc Brake  Emission  Collector Assembly
Ul

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_

h->
00
                                                                   INBOARD RING AND
                                                                    CALIPER COVER
                          Figure 5-13(b) - Major  Portions of Disc Brake Emission Collector Assembly

-------
Figure 5-14 - Disc Brake Emission Collector Assembly - Exploded View

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                                                             • BRAKE HYDRAULIC
                                                                    LINE
                                   BRAKE PAD
                                 THERMOCOUPLE
DRIED AND FILTERED
    INLET AIR
     Figure 5-15 - Front Disc Brake  Emission  Collector Installed on Vehicle

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  BRAKE PAD
THERMOCOUPLE
  Figure  5-16  -  Back View of Front Disc Brake Emissions Collector
                 Showing Instrumentation

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                                      SLIDING SEAL
                                     RETAINING PLATE
                                   GROOVE MACHINED
                                  INTO OUTBOARD SHIELD
      Figure 5-17 - Initial Design (MKI)  for Rotating Seal of Disc
                    Brake Collector
      5.5.2.2   Final Design
                A new sealing system was designed, using  a shaft-type
spring-loaded seal, of commercial manufacture, made  of graphite-filled
Teflon.  Figure 5-18 shows the drawing of the sealing system and Fig-
ure 5-19 shows the details at the sealing surface.

      5.5.3   Thermal Control Aids

              During preliminary testing, it was  apparent that the shrouded
disc brake was running measureably hotter than the unshrouded disc brake.
Therefore, various cooling aids were devised to reduce this temperature
differential.  Three cooling aids were used:

      (1)  Black oxide coating of the shroud to improve heat radiation.

      (2)  Water sprinkling system connected to the  windshield washer
           pump for cooling.

      (3)  Open or mag-type wheel for improved convective cooling of
           the shroud.

These additions are shown in Figures 5-20 and 5-21.

-------
                                                             4*8 TWO ./flrt/ip DePTH - HOueS
                                                               UOT BcifcOC.! ~THQ.O SOCtc.
                                                                                               -/8 n/U 06PTH- HOUSS
                                                                                     DOT gneaic. Tfteo saeic.
                                                                                        HOLES eO-SPC otJ 7-125 6-C.
                                                                                                         §EMO.	MUCH FILE	j
                                                                                                         LIHOP              T"

                                                                                                         CTION               |

                                                                                                         -F.D ,»,,d  «c.»niiff"
                                                                                                      rE: THB IS A BC/RLD INTERNAL DRA*HG.|oe
-------
DISC
                                                        --4-
                                                          HUB
                                               4340 PR ESS FIT
                                               RING - RUBBING SURFACE
                                                  GRAPHITE
                                                  FILLED
                                                  TEFLON
                                                  SEAL
                                                                       n
                                                                       di
                                              DISC BRAKE
                                               SHROUD
      Figure 5-19 - Details of  Disc Brake Collector  Rotating Seal
5-24

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                           a   SHROUD
                           •I THERMOCOUPLE
                                                                                       WATER SPRINKLING

                                                                                           SYSTEM
I
to
Ln
                               Figure 5-20 - Front Disc  Brake Emissions Collector  Showing Thermal

                                             Control Aids

-------
Ul
r J
                                SHROUD
                             THERMOCOUPLE
OPEN WHEEL
 (MAG TYPE)
                                        Figure  5-21 - Right Front Wheel of Test Vehicle

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5.6   DRUM BRAKE COLLECTOR

      5.6.1   Initial Designs and Rotating-Seal Problems
              The original concept for the sample collector on the right
rear collector was planned such that the drum and backing plate formed
the shroud along with a rotating seal.  This approach was used in order
to minimize changes to the cooling efficiency of the drum.
              The first design concept (MKI) was a face seal of Teflon
kept in contact with the polished edge of the backing plate by a silicone
rubber 0-ring (see Figure 5-22).  This seal had a short service life, be-
cause of alignment problems and the high rubbing speeds.
              The second design concept again attempted, to use the back-
ing plate and drum as the major components of the shroud.  However, this
design (MKII) incorporated a shaft-type spring-loaded seal, of commercial
manufacture, made of graphite-filled Teflon.  The seal manufacturer in-
dicated that this seal could sustain the rubbing speeds and temperatures
involved (2000 ft/min and 400°F).  This seal design is shown in Fig-
ure 5-23.  Figure 5-24 shows the modified backing plate and drum made
from this design.  Figures 5-25 and 5-26 show front and rear views of
the system as mounted on the vehicle.  The seal in this system failed
                                                  0.23"
   12.37"
   DIA.
                                                           TEFLON
                                                           SEALING
                                                            RING
                                                      BACKING PLATE
                                                                            "9
                                                                            Q.
          Figure 5-22 - First Seal Design (MKI) for Drum Brake
                                                                    5-27

-------
 10
                              S.K W/KING

                         II.030D.J?6F
                                                                     ZI8 D.THRU
                                                                    C'BOEE^-403.
                                                                     16 HOLES EQUI-SPCD
                                                    "-060a
                                       CBOKE-ZOOP.X
                    10.700 D.            .I4ODP. 1C, HOLES
                    5.F. W/5UPP.PING      EQUI-SPCD
                                    PLT
                                                 Z-IOO B.C.
                                                                   I/.905D.
                                                                 5.F.WITH SUPP.R1NG
                              WITH RET. RIWG
MINU'CUT — ^


C(.EflR)
3
II.3ZC



3D.
in a
i
7AD

-
-\ i
|v


r
.75C

                                                                        -»a-3ZU*JCTHOTHRU
                                                                          16 HOLES E
-------
       SEAL RUBBING
         SURFACE
                                           SPRING LOADED
                                            TEFLON SEAL
(a)  Modified Rear Brake Drum Backing Plate  Showing  Spring-Loaded
    Teflon Seal
       HARDENED
       STEEL RING
SEAL RUBBING
  SURFACE
 (b) Modified Rear Brake Drum Showing Hardened Steel Ring for
     Rotating Seal
          Figure 5-24 - Details of MKII Rotating Seal

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                                    BRAKE LINING
                                 THERMOCOUPLE LEAD
                                 EMERGENCY BRAKE
                                     CABLE
SILICONE RUBBER
   SEALANT
Figure  5-25 - Rear Drum  Brake Emission Collector

-------
after a short time as shown in Figure 5-27.   On investigating the failure,
three major problems were found:

      (1)   High interface speeds (1450 ft/min at 40 mph).
      (2)   Increase in seal interface pressure because of lack of
           concentricity and expansion of the drum.
          y
      (3)   Heat input to the seal from the braking action and dis-
           tortion of the drum from the braking action.

      5.6.2   Final Design

              In order to correct the problems described above, a third
seal design (MKIII) was developed.  This design removed the rubbing seal
from the drum to the axle housing area, decreased the diameter (and thus
the rubbing speed) of the seal and improved concentricity by using ac-
curate alignment of components and by modifying the rear axle hub to
align the drum concentric to the axle bearings within 0.001 inch.  A
tapered lead was used on the axle hub to facilitate mounting of the drum.
This design is shown in Figure 5-28.  An. outboard view of this sytem
without the drum is shown in Figure 5-29.  Outboard and inboard views
of the assembled system are shown in Figures 5-30 and 5-31.  This is
the system which was used in all testing.

5.7   CLUTCH COLLECTOR
      The clutch collector system consisted mainly of a filtered air
inlet and an outlet to the sample storage system with all other external
holes sealed.  A schematic of the system is shown in Figure 5-32 and a
photograph of the system installed is shown in Figure 5-33.
                                                                    5-31

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    Figure 5-26 - Rear View  of  Rear Drum Brake Emissions  Collector
                  Showing  Instrumentation
         RUBBING SURFACE
            SEPARATED
            FROM SEAL
                                                       P-82-196-2
Figure 5-27 - Completely Worn Seal  from MKII  Rear Drum Brake  Collector

-------
                                                      DRUM
                                                          BRAKE
                                                          LINING
GRAPHITE
FILLED
TEFLON
SEAL
      Figure 5-28 -  Sectional View of Drum Brake Shroud  (MKIII)
                                                                       5-33

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-
JL
-
                                                                                                NUT AND SCREW
                                                                                               REPLACING RIVET
                       BRAKE LIMING
                      THERMOCOUPLE
                              Figure 5-29 - Outboard View of Rear  Drum Brake Emissions Collector
                                            Interior

-------
U:
I
Ul
                                         PRECISION DRUM
                                         CENTERING HUB
                                  Figure 5-30 - Assembled Rear Drum Brake Emissions Collector

-------
I
u>
                                                                               AXLE SEAL AND

                                                                                STATIONARY

                                                                                 SEAL RING
                               Figure 5-31 - Inboard View  of  Assembled Rear Drum Brake  Emissions

                                             Collector

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                                                                 FIREWALL
                                                                                                 AIR FILTER
                                                                                                 (TO REMOVE
                                                                                                 H20&C02)
                                                                                                     TRANSMISSION
                                                                 EMISSIONS
                                                                COLLECTION
                                                                   DUCT
                                                                                       CLUTCH
                                            Figure  5-32  - Emission  Collection System for Clutch
Co

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OJ
00
                                          Figure 5-33 - General View  of  Covered Clutch

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                               SECTION 6
    INERTIA DYNAMOMETER TESTING OF THE DISC-BRAKE  COLLECTOR SYSTEM


6.1   OBJECTIVES
      There were  three  major  objectives for the inertia  dynamometer tests.
First, it was  necessary to  demonstrate that a brake can  be  completely
enclosed and not  change in  its  mechanical  operation.   Second,  it was nec-
essary to demonstrate that  the  thermal response would not be seriously
altered compared  to  the normal  brake  operation.  Finally,  the most crit-
ical unknown was  the rotating seal operation.

      6.1.1   Demonstration of  Collection  System Operation

              The disc  brake  on the vehicle was designed to operate as a
relatively  open brake with  a  substantial air flow  over its  component parts.
Shrouding of the  caliper and  rotor was a radical change  from its original
designed operating mode.  The shrouded brake for emissions  collection was
a unique piece of hardware  and  thus it required testing  on  the inertia
dynamometer, where modifications and  adjustments could be made rapidly
and rationally.

      6.1.2   Thermal Response
              It  was known  that shrouding  would change the  brake cooling.
However, the effects of pulling air through the brake shroud even while
the vehicle was stationary  would negate some of the shielding effect of
the shrouding.  Thus it was necessary to determine the thermal response
of the shrouded brake compared  with that of its original design and to
ascertain the  effects of any  thermal  differences.

      6.1.3   Rotating  Seal Durability
              At  the beginning  of the program, it  was believed that the
rotating seal  life would be the most  critical problem.   Several questions
arose.  Would  the initial design be suitable?   Was a good back-up design
available?   Would any rotating  seal survive under  the conditions of opera-
tion?  Were the claims  of the seal manufacturers accurate  and reliable?
Thus the most  critical  objective of the inertia dynamometer test was to
demonstrate the operation of  a  suitable rotating seal and  to demonstrate
its durability.

6.2   DYNAMOMETER TEST  RESULTS

      6.2.1   Sealing Practices for Disc Brake Collector

              Figure 5-14 shows the major  portions of the  front disc brake
collector.   The silicone rubber gaskets form the major portion of the
                                                                     6-1

-------
seals between the joints of the metal shroud.  Once assembled on the wheel
assembly, there were many leaks around the small screws holding the shroud
together.Other leaks appeared at the welds on the outboard shield and the
fittings on the modified dust shield.  The leaks around the welds^were
eliminated by returning the parts to the shop for additional welding.  The
other leaks were eliminated by the liberal use of cured-in-place silicone
rubber (see Figures 5-15 and 5-16).

      6.2.2   Thermal Response Results
              The first testing performed was to determine the thermal
response of the shrouded disc brake as compared with that of the unshrouded
disc brake.  The inertia dynamometer used was set up to simulate a load
of 1200 Ibs  on the brake, which is approximately 25 percent of the vehicle
test weight (Figure 6-1) .  Each stop was from 30 mph to 0 mph at 300 psi
line pressure.  Stops were made at the rate of one per minute.  The tests
were run in still air.  Figure 6-2 is a plot of temperature versus time
for a thermocouple located in the outer pad and a thermocouple mounted
on the backing plate.  The solid curves are for the regular or unshrouded
system, while the dashed curves are for the shrouded system, with no air
being pumped through the system.  Figure 6-2 shows that the shrouded brake
heats faster than the unshrouded brake which was to be expected.

              Figure 6-3 is a plot of the data from a series of tests on
the shrouded disc brake system for thermal response of the outer brake pad
under various air flow conditions.  The plot shows temperature versus total
energy input to the brake.  The lowest curve on the plot is for the un-
shrouded brake and the highest is for the shrouded brake with no air flow
as previously shown in Figure 6-2.  The two middle curves are for air
flows of 64 and 110 standard cubic feet/hour.  The results show that
increasing the air flow above about  60 SCFH (i.e., doubling the flow)
had little effect on the cooling of the brake.  Thus 60 SCFH was chosen
as the flow to be set in the test vehicle.

      6.2.3   Rotating Seal Operation

              The initial rotating seal design described in Section 5»5.2.1
did not provide a suitable seal.  It was therefore replaced with the de-
sign described in Section 5.5.2.2.  The following tests were performed
with the second design.

              Testing was done to determine rotating seal effectiveness.
The method used to determine the seal leakage rate was to apply air pres-
sure to the closed shroud at 3.5 psi and measure the time required for the
primary pressure regulator reading to drop from 1500 psi to 500 psi while
the tank valve was closed.  The total flow through the secondary regulator,
set at 3.5 psi, was about 137 cc during this time.  Figure 6-4 shows a
plot of the leakage times versus wheel speed for a new seal, both lubri-
cated and unlubricated.  As can be seen, the leakage time increases as
speed increases for both lubricated and unlubricated seals.  Since the
6-2

-------
    Figure  6-1  -  Disc  Brake  and  Emissions  Collector Assembly  Installed
                 on  Dynamometer
lubricated seal had lower leakage rates, the vehicle tests were all run
with lubricated seals.  This leakage test method was used throughout vehi-
cle testing and seals were changed whenever the leakage rate fell below
20 seconds on a cold system.

              One seal was then tested for a total of seven hours at 50
mph and the results of the leakage tests versus speed are shown in Fig-
ure 6-5.  The seal was removed after testing and inspected.   Figure 6-6(a)
shows that most of the seal experienced little wear during the test.
However, one section, approximately one inch long, showed abnormally high
wear to a point of imminent failure (Figure 6-6(b)).  This was apparently
caused by spring distortion in this area causing higher pressure.  Sub-
sequent seals were inspected for this defect prior to assembly and this
problem was avoided in all subsequent tests.
                                                                    6-3

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                 400-r
                                REGULAR SYSTEM (EOM)
                        ___ — SHROUDED SYSTEM
                      CHANGE    O OUTER PAD TEMPERATURE
                                BACKING PLATE TEMPERATURE
20       40
                                          60      80      100
                                             TIME (MINUTES)
                                                                120      140      160
              Figure 6-2  - Disc Brake  Comparative Thermal Response Time
                             (Static Air)
   400 -,
<
cc
   100-
                      O	O UNSHROUDED 7/22/71
                      O—O SHROUDED W/NO AIR FLOW 9/29/71
                      a—£ SHROUDED W/64SCFH AIR FLOW 12/10/71
                           SHROUDED W/110 SCFH AIR FLOW 12/14/71
                                6        8       10       12       14

                               TOTAL ENERGY INPUT (CUMULATIVE STOPS/UNIT TIME)
                                                  16
                                                           18       20
          Figure  6-3 -  Comparative Thermal Response Tests on a  Disc  Brake
       6-4

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            100-
                                   SEAL LUBRICATED
                                      WJTH DUPONT -
                                   —- KRYTOX 24OAC '
                                                       V
                   UNDESIRABLE
                              20      30

                                  WHEEL SPEED (MPH)
Figure 6-4 -  Seal Leakage  Versus Flow  for Disc Brake Emissions  Collector
              Showing Differences Between Dry and Lubricated Seals
                                 WHEEL SPEED(MPH)
    Figure 6-5 - Seal Leakage Rate Versus  Speed Showing Differences
                  Between New and Used Seal
                                                                          6-5

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                              (a) Normal Worn Seal
                                                             P-8 2-99-3


                                                              P-8 2-99-3
                  (b) Abnormal Wear to the Point of Imminent Seal Failure

     Figure  6-6 - Seals From Disc Brake Emissions  Collector Showing
                   Normal and Abnormal Wear
6-*

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              A new rotating seal was installed at the beginning of the
tests described in the next section.   The initial seal integrity was
equivalent to that of the seal used during the durability test runs.
Figure 6-7 shows the data for this seal.   The seal integrity was found to
improve as the seal wore in. Moreover, the leakage rate further decreased
as the wheel speed increased.  Finally, the data for this seal agreed with
all the trends shown by the earlier seals.

      6.2.4   Emission Collections
              A series of dynamometer tests were made to check out the
operation of the entire disc brake emissions collection system.  Identify-
ing the tests by a year-month-day date code, a total of three tests were
run:
              Test 11222:  Baseline

              Test 20105:  Baseline repeat

              Test 20108:  Baseline plus  spray

Test 20108 was similar to the other two tests except that a mixture of
5 percent sodium chloride and 5 percent barium sulphate in water was
periodically sprayed at the emissions collector.  The salt and barytes
(50 percent through 200 mesh and 50 percent through 325 mesh) were used
to simulate a fall-winter slushy-wet road condition.  Barium sulfate
was used in place of sand so that the barium could be used as a tracer
along with the chlorine in subsequent X-ray fluorescence analyses if
needed.
              Each of the tests was run for two hours on the inertia dy-
namometer.  Pre-run and post-run time added to the total.  During the
two-hour run, 40 brake stops were made from 30 mph at 8ft/sec2 decelera-
tion rate (considered a normal stop).  The wheel was run at 30 mph between
stops.  The temperature-versus-time plots for both the backing plate and
the outer brake pads are shown in Figure  6-8.  The reproducibility of
Tests 11222 and 20105 was good.  As expected, Test 20108 ran cooler be-
cause of the cooling spray.

              Table 6-1 summarizes the dynamometer test results for flow
rates, temperature control, and particulates collected.  A slight decrease
in carrier gas flow rate was seen as  the  filter picked up wear debris;
this agreed with previous laboratory test data of pressure drop versus
flow rates for Nuclepore membranes.  The  temperatures of the transfer
line and filter assembly were held at 200 +_ 20°F, the target temperature
range, for the two base-line tests.  The  transfer-line temperature for
Test 20108 fell below this for a brief period because of cooling effect
of the spray.   However, this was not  considered a problem.

              The particulates data are also given in Table 6-1.  The
wear debris on the filter was representative of normal vehicular brake
wear debris found in drum brakes and  trapped from previous Bendix sample
                                                                     6-7

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400
300
       Test 11222
	Test 20105
       Test 20108
   Prior to Test
A After Test
 10
                                        30           40
                                 WHEEL SPEED (MPH)
        Figure 6-7  - Rotating  Seal Leakage Rate Versus Wheel Speed
                      for Disc  Brake Emissions Collector
                                                             60
6-8

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   300
                                            RUN NO.  11222
                                                    20105 	
                                                    20108
                                 60

                                 TIME (MIN.)

                      (a) BACKING PLATE TEMPERATURE:
120
   300
o, 200-
LU
CC
D
CC
UJ
Q.

HI
   100-
                    30           60           90

                                  TIME (MIN.)

                           (b) PAD TEMPERATURE:
120
     Figure 6-8  - Disc  Brake Emission Collector Temperature
                                                                       6-9

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dynamometer tests.  The shroud  samples  contained mainly grease and some
Teflon-graphite wear particles  from the rotating seal.  The amount of
grease required was not known at  the start of these tests.  A liberal
amount was used initially.  Due to  the  heat of the rotating seal and to the
air flow through  the rotating seal  (slight vacuum in the shroud), the
grease flowed into the shroud and coated a portion of the inside surface
near  the rotating seal.  This grease film attracted and held the wear
debris.  Assuming that the brake  lining wear debris fraction* of the
shroud sample is  a constant (VLO  weight percent), the total particulates
produced for each of the three  tests agreed very well.  The mean was
17.4  + 0.3 mg.  The air-borne fractions collected on the filters showed
a wider variation with a mean of  12.8 +_ 0.5 mg.

      6.2.5   System Integrity
              The third test in the preceding section was carried out to
ascertain system  integrity under  simulated harsh road conditions.  This
test  was run in same manner as  the  first two tests except that a mixture
of 5-percent sodium chloride and  5-percent barium sulphate in water was
sprayed at the emissions collector  system.  A total of two liters of this
mixture, used to  simulate fall-winter slush conditions, was sprayed on
the system during the test.  No traces  of salt or of barium sulphate were
observable on the inside of the collection system after testing.  The
temperature data  for the heated transfer line and particulate filters and
the particulate collection results  for  these tests are shown in Table 6-1.
These results show that no salt entered the shroud system, and prove the
integrity of the  system used in vehicle testing.
             Table 6-1 - Summary of Dynamometer Test Results
RUN
NUMBER
11222
20105
20108
CARRIER AIR FLOW (SCFH)
Initial
36
36
36
Final
31
25
26
TEMPERATURES (°F)
Transfer
Line
190-210
180-190
170-220
Filters
180-205
190-220
190-215
PARTICULATES COLLECTED (mg)
8 V Filter
10.6
9.6
10.2
0.2 |j Filter
1.7
3.6
2.7
Shroud*
48.4
41.8
46.6
Total**
17.1
17.4
17.6
REMARKS
Baseline
Baseline repeat
Salt spray used;
none detected
inside collector
*Includes grease and Teflon-graphite wear particles from seal (probably >90% of amount shown)
*Includes 10% of shroud figure
 f\
  No assumption as to the actual content of wear debris in the samples
  taken from the brakes during the vehicle tests was necessary.  Much less
  grease was used and practically none of it entered the shroud during  these
  tests.
 6-10

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                               SECTION 7

                        VEHICLE TEST SCHEDULES
7.1   RATIONALE

      7.1.1   Brakes
              For a given vehicle brake system,  friction material wear
is primarily a function of the duty cycle.   For  light duty cycles, where
pad and lining temperatures remain under 350°F,  low wear results and is
primarily due to the  abrasive and adhesive  wear  mechanisms.   Heavier duty
cycles at higher temperatures give some combination of thermal,  abrasive
and adhesive wear.  Under severe heavy duty where the use borders on
abusiveness brake fade may occur.  The inability of the brakes to hold
the friction level results in part from the formation of gases (and wear
debris) at the interface.
              The amounts and types of gaseous and particulate emissions,
as a function of brake duty,  are not known.  Moreover, as brake  linings
age, changes such as  "hardening" occur, possibly with changes in the wear
properties.  Also,  until disturbed, portions of  the particulate  emissions
are known to be retained inside certain areas of the foundation  brakes.
Consequently, it is necessary to select a vehicle test program which will
provide some combination of normal and heavy duty service.

      7.1.2   Clutches

              For a given vehicle, the friction  material wear in the clutch
is primarily a function of the duty performed.  However, in most clutch
applications, the energy absorption and temperature rise are usually less
than in normal brake  operation.   Thus the wear and emission rates in clut-
ches were expected to be very low.

7.2   TYPICAL TEST CYCLES

      Several acceptable vehicle test cycles have been established and
used by friction materials and brake system manufacturers.  These are
varied according to life and  performance requirements, and for various
stages of friction material conditions.  The following test cycles appeared
to be suitable for this program.

      7.2.1   Burnish

              A portion of the SAE Recommended Practice:  Brake  System
Road Test Code - Passenger Car (SAE J843a)  is called the Burnish.  This
                                                                     7-1

-------
test cycle is  always  used when the brakes are relatively new and thus is
a part of the  break-in procedure for new brakes.   The test requirements
are:
      Stop speed:           40-0 mph

      Stop deceleration:    12 fpsps
      Stop interval:        As required to achieve
                           250°F initial brake
                           temperature in a maximum
                           of one mile.
      Cooling  speed:        40 mph (moderate acceleration
                           to cooling speed).

      Stops required:      200.
      Optional:             Inspect and/or adjust  brakes
                           after burnish cycle.

      7.2.2   Baseline
              Since there was no cycle in SAE J843b comparable to a re-
peated, low duty-type baseline test, it was found necessary to adapt a
portion of some other longer test cycle.  This test would be used to
serve as a reference  for wear rate and brake emissions after other low
and heavy duty test cycles.  The baseline test selected was three days
(12 circuits)  of the  Detroit Traffic Test schedule described below.

      7.2.3   Detroit Traffic Test
              The Detroit Traffic Test is used primarily to evaluate
friction, life,  and noise of commercial brake products.   The normal oper-
ating range for passenger car brakes in the test  is 180 to 280°F.  This
condition constitutes what  a brake engineer calls a low-temperature wear
test, but is actually somewhat more severe than for most driving.  Test-
ing is intentionally  accelerated to reduce test costs, consequently the
test tends to  be more severe than average driving.

              Table 7-1 describes the detroit Traffic Test route as modi-
fied for this  program.  The basic downtown circuit remains the same; only
the starting and finishing routes are slightly altered.   Each circuit
begins with elevated  brake temperatures.  The vehicle merges and flows
with the traffic during the prevailing traffic conditions.  The following
variations occur:

      Stop speeds:         Variable:  45-0 mph maximum.

      Snubs*:               Variable:  45 mph maximum.
      Stop deceleration:   Variable:  20 fpsps maximum.

      Stop interval:        As required to maintain flow
                           in traffic.
*
 Decelerations to lower speeds, but not stops.
7-2

-------
           Table  7-1  -  Detroit  Traffic  Test  Route   (Modified)
A.  Drive  from Bendlx Research Laboratories  (BRL)  to 12-Mile Road and Woodward Avenue via the following rout
      Left on Civic Center Drive to Greenfield Avenue
      Left on Greenfield Avenue to 12-mile Road
      Right on 12-Mile Road to Woodward Avenue
      Turn right on Woodward Avenue and park on Service Drive to check instrumentation.
B.  Detroit  Traffic Route:
      Starting on Woodward Avenue (just South of  12-Mile Road), drive south to  Adams Avenue
      (starting point of downtown loop).
      Right  on Adams Avenue (West) to Park Avenue
      Left on Park Avenue to Bagley Avenue
      Right  on Bagley Avenue to Third Avenue
      Left on Third Avenue across Michigan Avenue to Fort Street
      Left on Fort Street to Griswold Street
      Right  on Griswold Street to Jefferson Avenue
      West on Jefferson Avenue to Washington Boulevard
      Right  on Washington Boulevard to Fort Street
      Right  on Fort Street to Cadillac Square
      Right  on Cadillac Square to Randolph Street
      Left on Randolph Street to East Fort Street
      Right  on East Fort to Brush Street
      Left on Brush Street to Macomb Street
      Left on Macomb Street to Randolph Street
      Cross  Randolph Street to Broadway Avenue
      Right  on Broadway to Witherell Street
      Right  on Witherell Street to Adams  Avenue
      Left on Adams Avenue to Woodward Avenue
      This completes one downtown loop.  Complete a second downtown loop  by continuing west to Park Avenue
      and following around and returning  to the corner of Adams and Woodward Avenues
      After  the Second downtown loop, turn right  and follow Woodward Avenue (north) to 12-mile Road
      Turn left, making U-turn around center island and return south on Woodward Avenue, crossing 12-Mile
      to park on Service Drive again to recheck instrumentation
      This completes one circuit of the Detroit Traffic Test.
C.  Return  to BRL from 12-Mile Road and Woodward Avenue by following route:
      After checking out instrumentation,  drive west on 12-Mile Road to Greenfield Avenue
      Left  on Greenfield Avenue to Civic Center Drive
      Right on Civic Center Drive to BRL
D.  Estimated time scheduling:
Time
8:00 -
8:15
8:30
10:15 -
12:00 -
12:45 -
2:30 -
4:15 -
4:30 -
8:15
8:30
10:15
12:00
12:45
2:30
4:15
4:30
4:45
AT
(mln)
15
15
105
105

105
105
15
15

Vehicle preparation
BRL to 12-Mile and Woodward
First circuit
Second circuit
Lunch
Third circuit
Fourth circuit
Return to BRL
Prepare vehicle for overnight layover
E.   Estimated Miles:
      BRL to route and return     12
      Each circuit 26.5 x 4      106
                                118 miles/8-hour shift.
      Estimated total miles:   12  x 118 = 1416 miles.
                                                                                                             7-3

-------
      Cooling speed:       Normal traffic speeds.
      Stops required:      As required in flow  of  traffic.
              The duration of the Detroit Traffic  Test  is not fixed for
normal original equipment manufacturers' testing.  For  the  purposes of
this program, a 12-day test duration was chosen.   Each  day  of testing
was expected to provide approximately 118 test miles which,  in turn,  was
expected to yield a total of approximately 1416  test miles.
      7.2.4   10- Stop Fade and Recovery
              A portion of SAE J843a is called  the fade sequence.   This
test cycle is used as the first high- temperature operation  of a friction
material.  The test is used to simulate a vehicle  making repeated  heavy-
duty stops.  The fade sequence is usually followed by a recovery sequence.
The test requirements are:
      Fade:
        Initial brake temperature:  150°F before first  stop.
        Stops required:             10»
        Stop speed:                 60-0 mph.
        Stop deceleration:          15 fpsps (in normal driving gear).
        Stop interval:              0.4 mile.
        Cooling speed:              60 mph (accelerate  at maximum  speed).
      Recovery:
        Cooling speed:              40 mph.
        Cooling interval:           1.0 mile.
        Stops required:             12.
        Stop speed:                 30-0 mph.
        Stop deceleration:          10 fpsps.
Lining temperatures are recorded before each fade  stop  and before  each
recovery stop.
      7.2.5   15-Stop Fade and Recovery
              The 15-Stop Fade and Recovery is comparable to  the 10-Stop
Fade and Recovery described earlier, except that an additional  5 stops
are made when the brakes are already very hot.
      7.2.6   Reburnish
i-n H,e *   < 1,    Reburnlsh P0"ion of SAE J843a is essentially similar
to the Burnish portion except that only 35 stops are required.
7-4

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7.3   SELECTED VEHICLE  DRIVING SCHEDULE
      Although there  are many acceptable original equipment manufacturers'
friction material  tests to measure a specific condition or combination of
conditions,  there  is  no one  test which adequately matches normal driving
conditions which would  be representative of all vehicles.  Consequently,
it became necessary to  devise  a rational and meaningful vehicle test
driving schedule.
      Table  7-2 lists the selected vehicle driving schedule for each ve-
hicle test configuration used in the program.  A total of seven test
schedules was chosen  and each was followed by a measurements procedure
(take emissions samples, measure wear, inspect systems, and replace worn
parts).  The first three tests — Burnish, After-Burnish Baseline, and
Detroit Traffic — represent the low-temperature tests.  The final four
tests — 10-Stop Fade,  After-Fade Baseline, 15-Stop Fade, and Final
Baseline —  represent the high-temperature tests.

      7.3.1   Burnish
             The  initial test is the Burnish.   The original equipment
and aftermarket linings mate and conform to the initial condition of the
rotor whether it is in  its original configuration, as-used condition after
vehicle test 1, or its  turned condition prior to vehicle test 3. It was
anticipated  that the  emissions would be different than those for worn-
in linings.

      7.3.2   After-Burnish  (A.B.)  Baseline
             The  second test is After-Burnish (A.B.)  Baseline.  This
three days of Detroit Traffic Test was run at this time so that the other
Baselines run at the  later times could be compared to  the A.B.  Baseline
for the amount and type of emissions.

      7.3.3   Detroit Traffic Test
             The  third and  longest test employed was  the 12-day Detroit
Traffic Test.  This test represents the low-temperature-wear or normal-
duty-wear tests.   The results of this test could also  be compared to the
A.B. Baseline Test.
             The  end of the Detroit Traffic Test was  the end of the low-
temperature-wear testing.

      7.3.4   IP-Stop Fade and Recovery

             The  10-Stop Fade and Recovery was the fourth test sequence
and the start of the  heavy-duty or high-temperature testing.  During
this test, the front  brakes  experienced temperatures above 500°F, while
the rear brakes experienced  temperatures above 350°F.   The combination
of increased temperature and increased duty was expected to change the
amount and type of wear debris generated, as compared  to the previous
low-duty tests.
                                                                     7-5

-------
                   Table 7-2 - Vehicle Test Schedule

Test

Burnish
Measurements*
After Burnish

(A.B.) Baseline
Measurements
Detroit Traffic
(Modified)
Measurements
10-Stop Fade and Recovery
Reburnish

Measurements
After Fade
(A.F.) Baseline

Measurements
15-Stop Fade and Recovery
Reburnish

Measurements
Final
Baseline
Measurements

Estimated
Time
(Days)
2.0
1.5
3.0

—
1.5

12.0
1.5
1.5
1.0

1.5
3.0
_

1.5
1.0
1.0

1.5
3.0
-
1.5

Total
Time
(Days)

3.5


4.5



13.5

4.0



4.5



3.5



4.5

38.0
Estimated
Lining Loss
(Mils)

5


5



10

10



5



10



5



Purpose

Lining
Preparation

Base Line
Data

Low
Temperature
Wear
High
Temperature
Wear


Base Line
Data


Abusive
Wear


Base Line
Data

  Take emissions  samples, measure wear, inspect systems, and replace
  worn parts.
7-6

-------
              The Fade and Recovery were then followed by the Reburnish
sequence.

      7.3.5   After-Fade (A.F.)  Baseline

              This fifth test sequence was identical to the second and
seventh test sequences (and similar to the third),  but only the conditions
of the friction materials had changed.  This test was expected to deter-
mine the permanent changes in the amount and type  of wear debris generated
for friction materials taken through high-temperature and heavy-duty stops.

      7.3.6   15-Stop Fade and Recovery

              The sixth test sequence was the 15-Stop Fade (and Recovery)
in which the friction materials were taken to even  higher temperatures
than for the 10-Stop Fade.  The five additional stops performed after
the brakes were already hot produced temperatures  above 575°F.  This is
abusive braking, and rarely occurs.  The emissions  generated were expected
to be different again, as compared with the low-duty tests and the 10-
Stop Fade.
              The Fade and Recovery were then followed by the Reburnish
sequence.

      7.3.7   Final Baseline

              The results of this seventh and last  test sequence can be
compared with the results of the identical second and fifth test sequences.
This test concluded the determination of the effects that high-temperature
and heavy-duty tests have on brake emissions.
                                                                     7-7

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                               SECTION 8

                  SAMPLING AND ANALYTICAL PROCEDURES


8.1   RATIONALE BASED ON COLLECTOR DESIGNS

      8.1.1   Particulate Emissions Collection

              During the braking process, particulate emissions are gen-
erated by the rubbing action of the friction materials and the rotors.
The OEM brake configurations (left wheels of test vehicle)  release emis-
sions which reside in either of two areas depending on the brake type
(Table 8-1),.   The disc brake releases much of the emissions to the atmos-
phere while a small amount remains in the brake.   The drum brake releases
a lesser amount to the atmosphere and retains sizeable portions on the
drum rubbing surface and on the brake parts.  The brake emissions collec-
tors perform two functions not encountered in normal brake operation:
collect all the debris generated and fractionate  the debris.   Table 8-2
summarizes the particulate emissions samples produced.

      8.1.2   Gaseous Emissions Collection

              During the braking process, gaseous emissions are also
generated by the heat associated with the rubbing action of the friction
materials and the rotors.   The OEM brake configurations release gaseous
emissions which again reside in either of two areas.  Most of the gaseous
emissions are released into the atmosphere;  some  of the high molecular
weight materials distill from the hot surfaces and condense on the cooler
brake parts.   The emission transfer lines used in conjunction with the
collectors therefore were heated so that almost all gaseous emissions
could be transferred to the gas collection traps.

8.2   PARTICULATE EMISSIONS REMOVAL FROM COLLECTORS

      8.2.1   Collection of Particulate Emissions
              A detailed step-by-step sequence was prepared for the col-
lection of brake and clutch emissions.   This information is included
as Appendix C.   The weights of each sample collected are reported in
Section 9 under Vehicle Test Results.

      8.2.2   Disc Brake Samples

              In all cases, three samples were obtained from the right
front disc brake collector:  sump sample (including debris in rivet holes,
on lining surfaces,  and inside caliper piston), wear debris which remains
in the brake;  surfaces sample (including all other debris remaining in
the brake collector);  and the airborne sample (debris collected on the
                                                                    8-1

-------
     Table 8-1  -  Comparison of Disc Brake Versus Drum Brake Operating
                  Conditions
Parameter
Type of system
Air flow
Emissions
Third-body
abrasive wear
Disc
Open
High
Relatively
few trapped
Relatively
none
Drum
Closed
Low
Much trapped
in surfaces
and in sump
Some
P-8 2-99-3
        Table 8-2  - Samples Produced by  Brake Emissions Collection
Sample
Sump
Surfaces
Airborne
Disc Brake
Trapped debris* - includes
that in rivet holes, on
pads and in caliper piston
Accumulated on shroud -
normally road dropout
Airborne samples collected
on filters
Drum Brake
Trapped debris* - includes
that in rivet holes, on
linings , and on drum surf ace+
+Provides third-body wear
Accumulated on brake surfaces*
Airborne samples collected on
filters
      *Normally not completely released during brake operation.  (This may be a
      "controllable" material which could be disposed of properly).
8-2

-------
8.0y and 0.2y Nuclepore filter train).  The contract did not require Bendix
Research Laboratories to sample the left front disc brake; however, some
samples were taken so that it would be possible to assess the quantity of
material remaining in an OEM configuration disc brake.  These data were
prepared for Section 9.

      8.2.3   Drum Brake Samples

              In all cases, three samples were obtained from the right
rear drum brake collector:  sump sample (including debris in rivet holes,
on lining surfaces, and on drum rubbing surface), wear debris which remains
in the brake; surfaces sample (including all other debris remaining in
the brake collector and on the brake surfaces); and the airborne sample
(debris collected on 8.Op and 0.2p Nuclepore filter train).  The contract
required that selected left rear drum brake samples be taken in order to
assess the quantity of material remaining in an OEM configuration drum
brake.  These data were prepared for Section 9.

      8.2.4   Clutch Samples
              Since the airborne samples taken from the clutch for vehicle
test l were extremely small compared to the corresponding airborne samples
from the brakes-, it was decided to accumulate the entire sump and surfaces
samples for all three vehicle tests.  These data were prepared for Sec-
tion 9.

      8.2.5   Improved Friction Material Weighing Procedure

              The original equipment drum brake linings and disc brake
pads were riveted to their corresponding brake shoes.  The weight of the
metallic shoe placed the combined weights in excess of 400 gm; the weight
could then be recorded to the nearest 0.1 gm.  The anticipated weight
differences of approximately 0.5 gm would have had less than desired
accuracy.  By removing the rivets, the weights of the friction materials
alone could be determined.  Since all friction material weights were
less than 200 gins in this condition, weighing on an analytical balance
was possible.  After the friction materials were dried in a vacuum oven
at 90°C, the weights were recorded to the nearest 0.01 gm, giving the
desired accuracy.  The linings were then refastened to the shoes by flat
head nuts and bolts for vehicle installation and testing.


8.3   ANALYTICAL PROBLEM DEFINITION

      8.3.1   Composition of Wear Debris

              The brake converts the kinetic energy of the moving vehicle
into heat,  absorbs the heat, and eventually dissipates it to the atmos-
phere*   As a result of the energy conversion at the stator-rotor inter-
face, the compositions and microstructures of the brake lining and rotor
surfaces are altered.
                                                                     8-3

-------
              At low service temperatures, the phenolic  resin  and organic
friction modifiers in the friction material undergo ploughing  and mechani-
cal damage before they convert on the surface to compositions  with slightly
higher carbon/oxygen ratios.  At somewhat higher use temperatures, the
resin and organic friction modifiers convert to carbon more  readily,  and
this in turn oxidizes to carbon dioxide.  At the same time,  the  asbestos,
converted asbestos, and other converted materials wear away  more rapidly
because of the reduced binder strength and volume at the surface.   At
still higher temperatures, the asbestos converts from its  fibrous form
to an olivine powder having little or no reinforcing value.  When heat
is generated at the sliding interface much faster than it  can  be dissipated,
the temperature rises and reaches a point where the lining or  pad compon-
ents decompose, oxidize, or melt.  The region near the sliding surface  of
the lining containing these reacted components is called the frictional
heat affected layer (FHAL).
              At low service temperatures, the surface asperities  of  the
rotor are mechanically worked and the surface becomes essentially free
of graphite.  Also, the cementite plates in the surface layer  are broken
up and distributed as fine particles in a ferrite matrix.  When  the sur-
face is subjected to very high temperatures,  martensite forms  at  the
rubbing surface, with an accompanying increase in surface hardness.
              Consequently, the thermal and mechanical forces which act
at the friction couple interface produce a complex chemically  and physi-
cally altered microstructure which cannot be  accurately described  for the
resultant wear debris.  Figure 8-1 shows the  thermogravimetric analysis
of typical rear drum brake wear debris.   Table 8-3 gives an  estimate  of
the chemical composition of wear debris.

      8.3.2   Analytical Methods for Asbestos and Their Rationale

              As pointed out earlier,  asbestos is a complex  inorganic
material with the approximate composition formula:


                Mg3 (S105)  (OH)4 or 3MgO • 2Si02 •  2H20


The basic unit has a fibril form.   Asbestos is readily identified when
alone or in simple mixtures at high concentrations  by the following ana-
lytical methods:

              X-Ray diffraction
              Thermal methods
              Microscopy

              Infrared analysis
8-4

-------
                  100
                   70
                   60
                   50 •
                        SAMPLE:
                              1969 VEHICLE
                            4641/H3133FROM
                            RIGHT REAR DRUM
                              40,000 MILES
                        SIZE.
oo
                                                           X-AXIS
TEMP. SCALE.

SHIFT    0
              100
              inch
inch
                                                                            ~2% MINERAL
                                                                          DEHYDROXYLATION
                                   Y-AXIS
                           SCALE  1-0   ma.
                    inch
        (SCALE SETTING X 2)
                                                                                                       RUN NO..
                                                                                                                  DATE 12-14-71
                                                    OPERATOR,
                                                               RDS
                                                  20
HEATING RATE.
ATM OXYGEN  40 CC/RATE

TIME CONSTANT.
                                100        200        300        400       500        600

                                                                    TEMPERATURE °C
                                             700
                                                       800
                                               900
                                                                            1000
                                               Figure 8-1 - Thermal  Analysis of Wear Debris

-------
      Table 8-3 -  Estimated Chemical Composition Characteristics
               •  of Wear Debris
Description
Low Molecular Weight
Degradation Products
Polymeric Components
Carbonaceous Material
Inorganics :
Mineral
Olivine
Oxides (from Lining)
Fe20 (from Rotor)
Asbestos
Percent
2-10 \
12-20 >
1-5 J
VLO-30
^20-40
0-10
5-15
<1




20-30


70-80

However, in complex mixtures,  or at very low concentrations, the analysis
for asbestos is very difficult.   In brake wear debris, the problem is
compounded because the reaction  products of asbestos, forsterite and
olivine, have similar elemental  ratios and similar X-ray diffraction pat-
terns.  The only sensitive method which can be used is microscopy.  In
extremely low concentrations,  asbestos is identifiable in the electron
microscope by its physical shape (tubular fibril), which is distinguish-
able from that of other fibers and particles.

      8.3.3   Microscopy Methods for Asbestos
              At the beginning of this program, there were one optical
and three electron microscopy methods for the determination of asbestos
content.  The optical microscopy method was established by the U.S. Public
Health Service with the Asbestos Textile Industry(8-1)* to monitor ambient
air quality for large asbestos fibers in areas of high concentration.
In this method, an asbestos content with more than 90 percent fibers col-
lected on a membrane filter was  examined at 400 or 430 diameters magni-
fication with phase contrast optics.  The phase contrast rendered the
background filter transparent and enhanced the viewing of the fibers.
Only  fibers greater than 0.5u in diameter and 5.0y in length were detected
and reported.  No fiber size degradation took place in this analysis.

              Two electron microscopy methods (developed by Battelle
Columbus Laboratories(8~2) and Mt. Sinai School of Medicine^8"3)) existed
 rv
 References appear at the end of this section.
 8-6

-------
at the start of the program while the third was just being introduced
(University of California, School of Public Health(8-4)). These methods
are compared in Table 8-4. The Battelle and Mt. Sinai methods are char-
acterized by asbestos fiber size degradation to produce more fibrils.
This size degradation was not desirable for this program, as one of the
objectives was to ascertain the size distribution of the asbestos fibers
in the brake emissions.   On the other hand, the University of California
method was desirable because of particle size preservation.  However, the
magnification range was  found to be low, making it difficult to see the
smaller asbestos fibers  and fibrils found in brake wear debris.

8.4   BENDIX ANALYTICAL  METHOD FOR ANALYSIS OF ASBESTOS IN BRAKE EMISSIONS

      8.4.1   Criteria and Flow Chart
              Three important criteria had to be met by the analytical
method used:  the very small portion of brake debris used had to be re-
presentative of the much larger sample collected;  the analytical steps
could not degrade the particle size distribution of the asbestos fibers
obtained; and the results obtained must be indicative of the actual as-
bestos content of the sample.   These criteria were met by the analytical
scheme outlined in Figure 8-2.

      8.4.2   Analysis of Brake Emissions

              A detailed step-by-step sequence was prepared for the ana-
lysis of brake emissions.  This information is included as Appendix D,
The asbestos content of  each sample analyzed is reported in Section 9
under Vehicle Test Results.

      8.4.3   Representative Sampling and Low Temperature Ashing (LTA)

              After desiccating the samples to remove adsorbed water and
weighing for material balance purposes, two representative sampling pro-
cedures were used.   In the first sampling, 10 fractions, each approximately
2 to 5 mg, were used to  accumulate approximately 20 to 50 mg of wear de-
bris (Figure 8-3).   If the total sample weight was less than 100 mg, the
entire sample was used.   The large amount of carbonaceous material was
responsible for the fluffy appearance of the wear debris.   Figure 8-4
shows a scanning electron photomicrograph of a group of several fibers
greater than 50 microns.   Their ends were not visible and their exact
length could only be obtained  by LTA or by destroying the wear debris
particle which,  in turn,  might have reduced fiber length.   The LTA process
is described in Figure 8-5.
                                                                      8-7

-------
oo
00
                                     Table 8-4 - Transmission Electron Microscopy  Methods
Magnification
Size Degradation
Size Distribution
Concentration Used
Minimum Detectable Limit
Size Detection (p)
Minimum
Maximum
Statistics
Customer
BATTELLE
40.000X
Yes
Changed Completely
Yes
'x-0. 000001%
0.03 X 0.09
0.20 X 10
20 Grid Openings
(vLOO Fibrils)
EPA
MT. SINAI
42.000X
Partial
Changed Slightly
No

0.03 X 0.09
0.20 X 10
6 Grids X 2 Openings/Grid
(VLO-100 Fibrils)
Asbestos Workers Union
U OF CALIFORNIA
3.000X
No
Unchanged
No
0.01%
0.05 X 1.5
0.50 X 40
Not Known
Asbestos Workers Union

-------
      SUMP
     SAMPLE
      SURFACES
       SAMPLE
      (WEIGHED)
   AIRBORNE SAMPLES

0.2ju FILTER   S.Oju FILTER

       COMBINE
n
di
01
                                                           T
  (SAME AS FOR
SURFACES SAMPLE)
WEIGH REPRESENTATIVE
      FRACTION
      (SAME AS FOR
    SURFACES SAMPLE)
                         LOW TEMPERATURE
                              ASH (LTA)
                        WEIGH REPRESENTATIVE
                              FRACTION
                            DISTRIBUTE ON
                           0.2juNUCLEPORE
                               FILTER
                               DIVIDE
  OPTICAL MICROSCOPY:
  (GLASS SLIDE MOUNT)
         I
        COUNT
 (400X PHASE CONTRAST)
                         ELECTRON MICROSCOPY:
                          (CARBON SANDWICH)
                               COUNT
                               (22,OOOX)
                                 T
                              RESULTS
            Figure 8-2 - Flow Chart for  Particulates Analyses
                                                                      8-9

-------
                                                            •H
            Figure 8-3 - Representative Sampling for Analysis
        Figure 8-4 - Wear Debris Collected on 8y Nuclepore Filter
8-10

-------
  RF PRODUCES ATOMIC OXYGEN
  WHICH REACTS WITH CARBONACEOUS
  MATERIAL TO FORM GASES AND
  VAPORS WHICH ARE CONTINUOUSLY
  EXHAUSTED BY VACUUM
                        PYREX REACTION
                           CHAMBER
                              t
                                                                           [M
                                                                           s:
                                                                           a.
OXYGEN
ATOMIC
OXYGEN

  TO
VACUUM
                  //      GLASS
                     SAMPLE BOAT'
                       •SAMPLE
                      Figure 8-5 - Low Temperature Ashing

-------
              A series of tests was run to determine the organic content
removal by the oxygen plasma on several types of samples.  The removal
rate varied according to sample type and state of subdivision:

                                              Removal Rate
                      Sample                     mg/hr


            Carbon Rod
              Small Piece (Large Area)             31
              Large Piece (Small Area)             21

            Phenolic Resin                       >15

            Filter Paper                          40

            Wear Debris                            4

Carbon rod was the standard recommended by the instrument manufacturer
who claimed a removal rate of 90 mg/hr.  This rate was never obtained.
For the carbon rod, the phenolic resin, and the filter paper, the removal
rate was dependent on surface area exposed to the plasma.  The wear de-
bris, in spite of a large surface area, exhibited very low removal rates.
Consequently, long periods were required for removal.

              The LTA process removed 15 to 30 percent of the sample
weight, which, in turn, effectively increased the concentration of the
asbestos content for counting purposes, as performed later.  Figure 8-6
shows LTA-treated wear debris as distributed on a 0.8y Nuclepore filter.
The large groups of asbestos fibers shown in Figures 8-4 and 8-6 are not
typical; in almost all cases single fibers and fibrils exist and the
larger groups are shown for illustrative purposes only.

              The second representative sample step is described in
Sequence 7B of Appendix D.   The appropriate LTA sample was taken in the
following manner:  approximately 10 fractions of approximately 0.05 mg
each (material held on tip of fine spatula) were placed in a tiny platinum
boat on a five-place analytical balance until 0.55 ± 0.05 mg,weighed to
the nearest 0.01 mg, was obtained.  This material was then suspended in
a liquid and distributed onto a 0.2y Nuclepore filter as outlined in
Sequence 7B of Appendix D and shown in Figure 8-7-  The manner in which
the value of 0.55 + 0.05 mg was obtained is described in the following
section. .

      8.4.4   Sample Distribution for Microscopy

              The amount of material to be examined by microscopy was
arrived at by trial-and-error.  A 47 mm filter loading of 10.0 mg was
too great, as the smaller particles were not seen or separated from larger
particles.  The sample shown in Figure 8-6 was prepared with 7.0 mg load-
ing and several areas of severe crowding or multi-layers of particles
were seen.  A further series of samples was made with filter loadings
8-12

-------

     (a)  LTA Wear Debris  on 0.8p  Nuclepore Filter - 500X
  (b) Asbestos Particle Located in LTA Wear Debris - 5000X




Figure 8-6 - SEM Photomicrographs of LTA Wear Debris Samples
                                                              3-13

-------
          Figure 8-7 - Uniform Sample Distribution onto Filter
down to 1.0 mg.  At the 1.0 mg level, the particles were sufficiently
spread out to permit viewing of each particle by electron microscopy.
However, to achieve consistently stable films, a further study was carried
out (Appendix E) and it was found that good electron microscopy results
could only be obtained by implementing the following changes in the ana-
lytical procedure:

      •  Use of a smaller grid opening (400 mesh screens) to
         give good support and higher thermal conductivity.

      o  Lower loading on filter (0.50 to 0.60 mg) for more
         uniform distribution.
 8-14

-------
      •  A,second  layer of  carbon to effectively "sandwich" the
         wear  debris  for both strength of sample and thermal
         conductivity improvements.

              In early tests, wear debris was collected on both Millipore
and Nuclepore  filters.  The smaller particles entered into the fibrous
network of  the Millipore filters as shown by scanning electron microscopy.
On the other hand,  the Nuclepore membranes readily exhibited the collected
wear debris on a relatively flat surface.  To avoid future qualitative
and quantitative problems with fiber identification, Nuclepore filters
were therefore selected for all further work in this program.

      8.4.5   Selected Microscopy Methods

              8.4.5.1   Initial Studies and Rationale
                                r
                        A survey of the available analyses for asbestos
particles in friction material wear debris or in ambient air samples
was made.  All methods found were satisfactory for total asbestos.   All
methods found  were unsatisfactory for asbestos particle size distribution,
as they all involved  a particle size reduction step for transmission elec-
tron microscopy  observation.  Fiber bundles similar to those shown in
Figure 8-6  did not permit sufficient electron beam penetration and good
images could not be obtained for qualitative and quantitative observation
when fibril ends were not present.

                        In  the very early tests, wear debris from a sample
dynamometer was  collected on the filter train of the 8.Op and 0.2y Nucle-
pore filters.  Both filters were examined by a combination of optical and
transmission electron microscopy. The following observations were made:
      •  When  the  total airborne sample was small, the particulate
         distribution between the filters was almost even.  As the
         total sample (sum of debris on both filters) became larger,
         the larger amount  of debris remained on the 8.0y filter.
         In effect, it became a finer filter and less material passed
         to the  0.2y  filter.

      «  The size  distribution on the 8.0y filter varied over a larger
         range;  the material on the 0.2y filter was finer and more
         uniform in size.
      «  Fibers  were  found  on both filters; fibers up to 2.0y diameter
         and 50y long were  located on the 8.0y filter, and up to
         0.9y  diameter and  3.6y long on the 0.2y filter.  The electron
         beam  could not penetrate the thicker fibers.

      •  Although  many nonfibrous particles were checked for crystal-
         linity  by electron diffraction, very little crystallinity
         was found.
                                                                   8-15

-------
                        Additional particulate analyses were carried out
for the airborne samples collected from the inertia  dynamometer  tests
described in Section 6.   The filters were examined  as collected  , without
any sample redistribution onto a single filter.  The following observations
were made:
      o  Asbestos fibers longer than 20 microns were obtained.

      o  Very fine fibrils were extremely difficult to detect in
         "as-collected"  airborne wear debris.
                        Based on the above studies, it was deemed neces-
sary to employ two magnifications.  To detect fibers greater than 5y,
a magnification in the range 400 to 1000 diameters, was required.  To
detect the finer fibers  and the ultimate fibrils, a magnification in
the range 10,000 to 40,000 diameters was required.
                        The following optical plus transmission electron
microscopy magnifications were selected:

                                        Fibers Detected (p)

                                      Minimum          Maximum
                                       d x 1            d x 1

      Transmission Electron
        at 22.000X                   0.03 x 0.10       0.50 x 35

      Optical (Phase Contrast)
        at 400X                      0.50 x 1.50         10 x 100

              8.4.5.2   Optical Microscopy Analysis for Asbestos

                        The U.S. Public Health Service procedure  outlined
in  Section 8.3.3 was modified for this program.  The procedure(°~1)
called for Millipore filters and the fluid used for phase contrast had
a refractive index of 1.460.  In the Bendix procedure with Nuclepore
Filters,  a fluid matching one of the refractive indices of Nuclepore
filters at 1.585 was substituted.
                        The procedure used is described in Sequence 8H
of  Appendix D.  Figure 8-8 shows the microscopist behind the Reichert
Zetopan as equipped with Heine phase contrast optics at 400 diameters.
A typical photomicrograph (Figure 8-9) shows fiber among the remaining
wear debris.

              8.4.5.3   Transmission Electron Microscopy Analysis
                        for Asbestos

                        The University of California School of Public
Health procedure, also described in Section 8.3.3, was modified  for this
program.  A magnification of 22,000 diameters was used instead of the
prescribed 3000 diameters because of the difficulty in seeing fibers below
O.ly in diameter.
 8-16

-------
     Figure 8-8 - Phase Contrast Optical Microscopy at  400X
      ' •*'"              *                       .
Figure 8-9 - Phase-Contrast Photomicrograph of Wear Debris - 400X
                                                                8-17

-------
                        The procedure used is described in Sequence 8B
of Appendix D.  Figure 8-10 shows the Hitachi Type HU-125E transmission
electron microscope used in this program.  A typical photomicrograph
(Figure 8-11) shows asbestos fiber among the remaining wear debris.

      8.4.6   Calculations From Microscopy Results

              8.4.6.1   Rationale and Microscopy Count Sheet
                        The ultimate asbestos fibril has been found to
be circular in cross section(8-5).  When the wear debris was spread thinly
over the flat Nuclepore filter membranes, each fiber remained flat when
viewed in the microscope, so that its projected diameter and length
             Figure 8-10 - Transmission Electron Microscope
 8-18

-------
could be measured.   The volume of each asbestos fiber was readily deter-
mined from the following formula:
                              „   TTd
                              V    4  x
where
      V = volume of material

      d = projected diameter measured
      £ = length measured

When two or more fibrils make up the larger fiber bundles, a larger-than-
actual projected diameter results.  Even fibers with elliptical cross
section were assumed to lay such that their largest diameter was parallel
to the filter.   In all cases, the volume- calculated from the projected
diameter and length was thus on the high side.
      For each .fibril  or fiber found,  it was necessary to determine its
dimensions and  calculate the volume of asbestos found.  Because of the
large number of  fibers,  this procedure became tedious.  To simplify fiber
sizing,  a Microscopy Count Sheet was developed .(Figure 8-12).   The cross-
hatched  areas are the  boxes which did not  follow the definition of a
fiber:   the length was required to be three or more times greater than
the diameter.  Each fiber found by the appropriate microscopy method was
classified into  the proper box containing  the projected diameter and
length of the fiber in question.   A typical microscopy count for a sample
generated in this program is superimposed  on Figure 8-12.

      8.4.6.2 Sample Calculation

             A typical  calculation is carried out in the following manner.
For each box, an average volume is calculated from,the formula:
where

      V =  average volume for box
     ~2                       2
     d =   average of  diameter  for box

      Si =  average length for box
                                                                    8-19

-------
             Figure 8-11 - Asbestos Fiber in Brake Emission
These values are given in Figure 8-13.  Then it is necessary to multiply
the number of fibers given in each box in'Figure 8-12 by the volume given
for the corresponding box as shown in Figure 8-13.
                        The typical microscopy count shown in Figure 8-12
is used to calculate asbestos content in the following manner.  The fibers
of each group are totaled as shown in Table 8-5.  The total number of
fibers per group (n) is then multiplied by the average volume per group
(V) to obtain the product (n x V).  All products are then totalled to
arrive at the total volume of asbestos detected.
                        Since only a fraction of the total area is ac-
tually scanned, the volume observed must be normalized to the entire area
containing wear debris:
Total Fiber
Volume  (by EM or OM)

  = Volume obtained  (cc) x
	Total Area of Filter	
(No. of Fields Counted) x (Area  of  a  Field)
     I  (n x V) x
                       990 mm'
                IF x  (Area of Field)

-------
                           MICROSCOPY COUNT  SHEET
Vehicle Test:    /
Schedule:       A-0-
Collector:
Sample:
Date:           7-2V-72.
                                            Total Sample Weight:  /86~./
                                                                              _mg
                                            LTA Weights (I/F):   38-8  I 3/.2-   mg
                                            Count Weight:        	Q .£2.
                                            Comments:
•x
o
o
o
(N
(N
g
o
          0.08
       0.08
         /
         0.25
           0.25
             /
             0.50
                         /
                        Illl
                             (D
                                /rrtf
iff
                                                        EM Field Size:
                                                           3.0 x 3. Op
                                                        No. of Fields:
                                                               ZOO


                                      FIBER LENGTH (u)
                                Illlll
                     7-2 5- 7Z.
Date Counted:
OM Field Size:  |8_ x  88_H
No. of Fields:
                                       ##«*•»#>#

                                            Microscopist:
                     Figure  8-12  - Microscopy Count Sheet
                                                                                    8-21

-------
                           FIBER  VOLUME CALCULATION
   o
   o
   o

   O)
   (N
                                                           EM Field Size

                                                              3.0 -x 3.On

                                                           No. of Fields
   o
   o
                                       FIBER LENGTH (u)
                                    3.0
                                 0,982.
                                        3.0
               3.19
                                        fZ.8
                                        33.2.
                                        (e.3,0
                                               10
7,30
                                              76-7
                                                        35
                                                     A3,
                                                     5-5,8
                            270
                                                           Z.3,3
                                  95,0
                                                           JC-S
                                                           1380
                                                           2,89
                                        39,3
                                        /190
                                        Z.3Z

                                          x.o3
                                                                  mo?
        Date Counted:

        OM Field Size:

        No. of Fields:
x 88U
                                             Microscopist:
                    Figure 8-13  - Fiber Volume Calculations
8-22

-------
                                                              **** ASBESTOS ANALYTICAL RESULTS ****
                       VEHICLE TEST:  1
                           SCHEDULE:  A. B.  BASELINE
                          COLLECTOR:  RIGHT  PEAR BRAKE
                            SAMPLE:  SUMP
                                         10F 0
0.464E-16
0.681E-16
0.100E-15
0.1476-15
0.215E-15
0.316E-15
0.464E-15
0.681E-15
O.LOOE-14
0. 1476-14
0.215E-14
0.316E-14
0.464E-14
0.6SIE-14
0. 100E-13
0.147E-13
0.2L5E-13
0.316E-13
0.464E-13
0.6B1E-13
0.1006-12
0.147E-12
0.215F-12
0.31AE-12
0. 4646-12
0.681E-12
0.1006-11
0.147E-1 1
0.2156-11
0.3166-11
0.464E-11
0. 6816-11
0. IOOE-10
0.147E-10
0.215E-10
0.316E-10
0.4646-10
0.6816-10
0. IOOE-09
0.1476-09
0.2156-09
0.3166-09
0.4646-09
0.681E-09
0.100E-08
0.0
0.0
0.0
0.0
0.550E
0.0
0.0
0.1656
0.0
0.275E
0.0
0.0
0.660E
0.0
0.0
O.llOE
0.0
0.495E
0.0
0.0
0.5bOF
0.0
0.0
0.0
0.0
0.0
0.575E
0.0
0.0
0.0
0.575fi
0.0
0.0
0.447F
0.0
0.639E
0.6i9E
0.0
O.P56F
0.0
0.0
0.0
0.0
0.0
0.0




06


07

07


07


07

07


06





04



04


04

03
03

04






                         DATE:  7-21-72
                          NO.:   104
LTA(I)= 0.38806-01
LTA(F)= 0.3120F-01
                                                                                                ASBESTOS PFPCENT =

                                                                                      10C 4       10C  5       10^ 6
                                                                                                                  EM SUB THTAL  = 0.5683E-06
                                                                                                                  flM SUB TOTAL  = 0.8148F-06
      TOTAL = 0.1383E-05
COUNT WEIGHT = 0.62006-03
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
I 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 I 1
1 1 1
1 1 1
1 1 1
1 1 - 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
II 1

1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
























































                                                    10F  1
                                                                                                 101=  5       irc r.
NJ
Figure 8-14  - Computer  Printout of Asbestos  Analytical  Results

-------
                         Table  8-5 -  Sample Calculation
ELECTRON MICROSCOPY
Fiber
Number
(n)
1
3
5
12
1
1
9
1
Fiber _
x Volume = n x V
(V x 10~15 cc) (x 10~15 cc)
0.20 0.20
0.50 1.50
1.31 6.55
3.50 42.0
11.3 11.3
10.2 10.2
27.1 243.0
88.0 88.0
E n x ? = 402.7
Total Volume
E
(No.
402.

= 202
(n x V) x (Area of filter)
of fields) x (Area of field)
7 x 10~15 990 x 106 y2
200 ^ 3 x 3 y2
x 10~9 cc
OPTICAL
Fiber
Number
(n)
9
9
2
5
1
1
4
MICROSCOPY
Fiber _
x Volume = n x V
(V x 10~12 cc) (x 10~12 cc)
0.982 8.92
3.19 28.7
13.5 27.0
12.8 64.0
29.4 29.4
33.2 33.2
76.4 305.0
E n x V = 496.22
Total VolumeOM
E
(No.
496.

= 316
(n x V) x (Area of filter)
of fields) x (Area of field)
2 x 10~12 990 x 106 y2
200 * 88x88y2
x 10~9 cc










n
66-ZB-d
Total Volume
(Total Volume).,.. + (Total Volume)..,
              Jin                UM.
                     (202 + 316) 10~9 cc  =  518 x 10~9  cc
Total Weight
518 x 10~9 x 2.50 ^ x  1000  SB.
                  cc         gm
                     1.33 x 10~3 mg
Asbestos Percent
0.00133     312

-OT  x  388  x
 8-24

-------
For the electron microscopy analyses at 22,000 diameters, the  area  of  a

field was  3 x 3 y2.   por the optical microscopy analyses at  400  diameters,

the area of a field  was 88 x 88 y2.  in electron microscopy  analysis,

402.7 x 10~15 cc was found for 200 fields:
        v          ^       -   x 	9  x 1      cc
        Volume (by EM)            (2Q()) x (3 x 3 y2)
                         202 x 10~9 cc
      Total Fiber      Specific    0 c, gm    _.,   T7  . ,   ,,   „..,
      „ n     t,   „„.,.  x „   .        2.56 •6—  = Fiber Weight  (by  EM)
      Volume (by EM)    Gravity          cc              &    \  j    '
                202 x 10~9 cc x 2.56 -SB = 0.00052 mg
                                     cc
                 Combined total for all  •_ „„,.,,,
                   ,   „   e    ,         = 0.00133 mg.
                 asbestos found
This amount of asbestos calculated is for debris which had been  slightly

concentrated in the LTA process.  Thus the asbestos percent,  as  related

to the original material, is obtained by the following expression:
          Asbestos    Total Asbestos Found      .     .  F    inr.
          _         =	„ .  ,	 x LTA Ratio •=• x  100
          Percent        Count Weight                 I





For the example given in Figure 8-12, the percent asbestos  for the sump

sample of the  right rear brake collected for the A.B. Baseline Schedule

of vehicle test 1 is found:
          Asbestos    0.00133   31.2   ......   _ ..-,_

          Percent   = 0762— X 3O X 10° = °'173
                                                                     8-25

-------
              8.4.6.3   Computerization of Calculations  and
                        Particle Size Distribution

                        The calculation of asbestos  content was  lengthy
and thus susceptible to computational errors.  Moreover,  over  150 such
calculations were anticipated for the program.  A computer  program was
therefore developed in conjunction with the Count Sheet  given  in Fig-
ure 8-12.  The uppermost horizontal row and the extreme  left vertical
column of markers are used to identify the box with  its  corresponding
volume.  The circled number is the number of fibers  found which  corres-
pond to that volume.  Unlike the manual calculation, grouping  of boxes
in threes is not required and for this reason the computer  calculation
is slightly different and slightly more accurate than  the manual
calculation.

                        The computer program is given  in  Appendix F.
Figure 8-14 shows the computer printout for the sample calculation given
in the previous section.  The computer printout gives  the asbestos
percent = 0.179 percent, which compares with the manual  calculation of
asbestos percent = 0.173 percent.

      8.4.7   Possible Sources of Error

              The possible sources of error for the  sampling and analysis
of particulate wear debris are listed in Table 8-6.

              The possible sources of error associated with sample pro-
cessing were minimized through the use of statistical  methods.   For sample
selection, two stages of representative sampling took  place:  weighing
prior to sample low temperature ashing, and weighing for  distribution
onto the filter.  Uniformity of sample distribution was  checked  by low
power optical microscope observation immediately after distribution.
This was further checked by the microscopy results as  shown in Figure 8-12.
Just under the number of fields reported for the electron microscopy re-
sults, the notation used shows 15 fibers found in 100  fields examined
on 2 grids from one side of the filter, while 18 fibers were found for
100 fields examined on 2 grids from the other half on  the filter.  Also,
for the optical microscopy results,  17 fibers were found  in 100  fields
on a sample taken from one side of the filter, while the  other side yielded
13 fibers.  These distributions were typical.

              As indicated in Appendix E,  a series of  tests was  run to
insure good samples for electron microscopy.   Membrane shrinkage  did not
occur and membrane curling was minimized.   No observations  in the  elec-
tron microscope were taken near membrane edges.   The sample distribution
was finalized after more than ten different sample weights were  examined
and then several different samples at the  same sample weight gave  repro-
ducible films in terms of stability  and counting.
8-26

-------
         Table 8-6 - Possible Sources of Error
SAMPLE PROCESSING
    Low Temperature Ashing
        Sample Selection
        Extent of Ashing
        Weighing

    Sample Distribution
        Sample Selection (From Vial)
        Sample Weighing
        Characteristics of Sample and Variations in
        Size Distribution
        Loss through Filter
        Filter/Funnel Interface Effects

    Sample Handling
        Air-Borne Dust Contamination
        Static Electricity
        Air Currents

MICROSCOPIC METHODS
    Sample Preparation
        Sample Identification
        Sample Redistribution during Cutting
        Membrane Stretching, Shrinkage, or Curling

    Sample Counting
        Depth of Field
        Width x Length Estimates
        Large Fiber Contributions
        Fiber Identifications (Asbestos Versus Olivine)
        Magnification Variations
        Statistics
                                                           8-27

-------
              Perhaps the largest sources of error occur in  the  sample
counting procedure,  for the following reasons:
              •  Width and length estimates of fibers and their
                 insertion into the proper box in Figure 8-12
                 (a borderline diameter such as 0.05 y which is
                 between lines 12 and 13 gives an average volume
                 difference of approximately 3) .
              o  Fiber identification difficulty, especially in
                 optical microscopy (asbestos or olivine).
              •  Number of fibers found and their statistics.

              These errors were minimized by counting a large number of
fibers and/or fields, whichever came first.  The target for  fiber count-
ing was 100 fibers in 100 fields in both  electron and optical microscopy.
This target was rarely obtained because of the very low content  of as-
bestos present in the sample.   A maximum number of fields to be  counted
for low fiber concentrations was also established (200 EM fields and
300 OM fields), to avoid unnecessary delays for very low concentrations.
              The largest effect found on the asbestos analysis was the
occurrence of a large fiber.  Its volume contribution significantly in-
creased the contribution, in either microscopy method, by 100-200 percent.
This could give up to a 50 percent change in the final calculation.  If
additional fields were counted or a replicate analysis made, a comparable
fiber was usually not found.  The large fiber was thus considered an
"outlier" and was not used in  the calculations.  In some instances, more
than one large fiber was found in a sample.  Replicate analyses  did not
yield similar fibers and the asbestos emissions result was significantly
different as shown in Table 8-7 for the following sample:  Vehicle Test
1, Detroit Traffic Schedule, right front brake, sump sample  (Example 1).

              The precision in the asbestos analytical results can be
estimated by considering the replication data given in Table 8-7.  The
percent deviations range from  0 to 79 percent; the average is +27 percent.
On the other hand, Figure 8-15 shows the variation of the maximum devia-
tion (given in Table 8-7) with the asbestos percent found.  The data
show that the maximum deviation for results with asbestos contents above
approximately 0.10 percent have a maximum envelope at approximately 20
percent, with averages at 12-15 percent.  The maximum deviation  increases
for asbestos content below 0.10 percent, where errors for the small
amounts of asbestos emissions  become less significant.

8.5   ANALYSIS OF GASEOUS EMISSIONS

      8.5.1   Method of Analysis
j*a< „ A +        8aS collection system (described in Section 5.4) was
designed to collect and separate condensable and noncondensable gases
         T        I'  BeCSUSe °f the hlgh vaP°r Pressure of the noncon-
         gases ln the activated-charcoal traps, storage took place at
8-28

-------
Table 8-7 - Extent of Error  in Asbestos Emissions Analytical  Results
EXAMPLE
NUMBER


1







3


4







6



7



8



9




10


SAMPLE
Vehicle Test 1
Detroit Traffic
Right Front Brake
Sump Sample
Vehicle Test 1
Detroit Traffic
Right Front Brake
Surfaces
Vehicle Test 1
Detroit Traffic
Right Front Brake
Airborne
Vehicle Test 1
A.B. Baseline
Right Rear Brake
Airborne
Vehicle Test 3
Detroit Traffic
Right Front Brake
Surfaces
Vehicle Test 3
Detroit Traffic
Right Rear Brake
Surfaces
Vehicle Test 3
Final Baseline
Right Front Brake
Surfaces
Vehicle Test 3
Final Baseline
Right Rear Brake
Sump
Vehicle Test 3
Final Baseline
Right Rear Brake
Surfaces :
Cumulative for
Vehicle Tests
1, 2, and 3
Clutch
Surfaces
ASBESTOS
PERCENT
0.247*
0.631
0.186

0.137*
0.085
0.091
0.116
0.052*
0.025
0.085
0.068
0.432*
0.554


0.013*
0.034


0.057*
0.045


0.087*
0.061


0.512*
0.386
0.511

0.237*


r


0.047
0.047

AVERAGE

0.355



0.107



0.056



0.493



0.023



0.051



0.074



0.470


0.228





0.047


MAXIMUM
DEVIATION

0.276



0.022



0.031



0.061



0.011



0.006



0.013



0.084


0.010





0.000


PERCENT
DEVIATION

+79%



+21%



+55%



+21%



+48%



+12%



+18%



+18%


+ 5%





0


    *Result reported in Tables 9-16, 9-17,  and 9-18.
                                                                     8-29

-------
  100H
   80-
O
LU
O
5
i
   60-
   40-
    20
                                                                 MAXIMUM
                                                                 AVERAGE
               T"
               0.10
-1	-1	1	
 0.20        0.30        0.40
        ASBESTOS PERCENT FOUND
0.50
           0.60
      Figure 8-15 - Variation of Maximum Deviation of Asbestos Analytical
                    Results with Asbestos Percent  Found

   -70°C with solid carbon dioxide packed around the traps.  The analytical
   procedures are given in Appendix D.  The primary method of analysis was
   gas chromatography for both  the noncondensable and condensable gases.

         8.5.2   Gas Handling System

                 The gas handling system used for the gas analysis is shown
   in Figure 8-16.  The system  included various sections designed to perform
   the following tasks:

         •  Gas inlet and fraction  traps -  used to separate air
            from the gases  of interest.

         •  Toepler pump and gas buret - used to transfer  the gases
            and measure their volume.

         •  Gas  chromatograph  transfer U-tube - used with  gas buret
            and  Toepler pump to inject a sample into the gas
            chromatograph  (Figure  8-17).
    8-30

-------
                                                    CALIBRATION GAS
                                                   STORAGE RESERVOIR
  G.C. SAMPLE TRANSFER
        U TUBE
     HIGH VACUUM
      MANIFOLD
MERCURY DIFFUSION
      PUMP
GAS FRACTIONATING
     TRAPS
                                                                        DEWAR CYLINDER
HELIUM SUPPLY
                                                                         VEHICLE GAS
                                                                      COLLECTION SYSTEM
    TOGAS
CHROMATOGRAPH
                                           TOEPLER PUMP
                       Figure  8-16  - Gas  Handling  System
                                                                                   8-31

-------
Figure 8-17 - Gas Handling System and Gas Chromatograph

-------
      o  Calibration  gas  storage volumes - used to store pure gases
        or known mixtures  which were used to calibrate the gas
        chromatograph.

              The noncondensable gases were to be handled first.   The
complete step-by-step procedure is described as Sequence 10A in Appen-
dix D.   The condensable gases were then handled and their procedure is
described  as  Sequence 10B  in Appendix D.

      8.5.3    Calibration of Gas Chromatograph

              Prior to any  analyses of samples generated by the vehicle,
it was necessary  to check out the gas handling system and calibrate the
gas chromatograph.  The gas handling system was set up in good working
order.  A  calibration gas from one of the gas storage volumes was expanded
into the high-vacuum  manifold.  By means of the Toepler pump, all of the
sample could  be collected and measured in the gas buret.  The sample was
then introduced into  the  G.C. transfer U-tube.  The helium flow of the
gas chromatograph was diverted so that the volume of gas in the gas chro-
matograph  transfer  tube  could then be introduced directly into the gas
chromatograph.  The volume  of gas introduced was calculated and the gas
chromatograph detector response was determined.  For a series of different
volume sizes  added  to the gas chromatograph, a calibration curve could
be made.  Figure  8-18 is  the typical detector response calibration curve
obtained for  carbon dioxide.  Similar curves were prepared for other
gases expected.
              The retention data for the column used were obtained in
the following manner. A  gas mixture containing air (nitrogen and oxygen),
carbon monoxide, methane, carbon dioxide,  water, and propane was  prepared
exterior to the system.   The mixture was stored in a separate volume.
Small samples could be introduced through the gas inlet of the gas handl-
ing system.   The  sample was collected in the gas buret and transferred
to the gas chromatograph.  Several different temperature programs for the
gas chromatograph column  were evaluated in order to obtain a reproducible
program  which would elute all gases predictably and well separated.•
Figure 8-19 shows the typical retention time calibration for low molecular
weight gases  which  may be present in the noncondensable gas traps.  The
components were separated on a column 6 feet long and 0.125 inch O.D.,
packed with Porapak Q.  The column was initially cooled to less than
-70°C with dry ice.  This condition was needed to separate N2, 02, and
CO.  The column temperature was then raised rapidly to 30°C to elute
CH^ and  C02.   The column  was then heated to 180°C at 10°C/min to elute
water, C^s,  and C4*s.

      8.5.4    Problems and  Interferences
              In Section  6.2.3, the integrity of the rotating seal was
discussed  along with  its  leak rate as measured under both static and
dynamic  conditions.  It was impossible to eliminate the leak completely.
Under static  conditions,  the flow through the seal was VL37 cc/min.  This
                                                                    8-33

-------
    1200
    1000-
 S  800

 X
 1
 D
 O
 o
 U-
 o
 cc
 UJ
 ED
600
 Z
    400
    200
             DETECTOR TEMPERATURE: 180°C
             DETECTOR CURRENT:     180mA
                0.20
                           0.40        0.60        0.80

                             NUMBER OF MOLES (X 10'5)
                                                      1.00
                                                                 1.20 i
           Figure  8-18  -  Detector Response for Carbon Dioxide

improved to about 50 cc/min under  the most optimum conditions.  However,
in all cases there was a gas flow  through  the rotating seal into  the
emissions collection system.

              The rotating seal was downstream of the gas drier and car-
bon dioxide removal bed (described in Section 5.2.1).  Thus the air
entering the rotating seal contained the normal atmospheric components
including carbon dioxide  and water in addition to oxygen, nitrogen, and
argon.  In heavy traffic, measurable amounts of carbon monoxide and nitro-
gen oxides were also expected  to be present.  The large amounts of carbon
dioxide and water  obtained proved  to be the major problem when the gases
were collected at  low gaseous  emission  concentrations such as in  the
 8-34

-------
H
o.


O
cc
O
UJ

UJ
Q
             CO
   0
           HEAT
   DRY  FAN  TO
   ICE  ON 32°C
CH4
                        CO
                                      6' 1/8" OD PORAPAK Q
                                          37 CC/ mm
                                      I
                                      12

                      -30°C TO 180°C @ 10°/ mm
•Ar
               IV
               01
               m

           18  S
  -70°C
       Figure 8-19  - Typical  Calibration Chromatogram for Low Molecular
                      Weight Gas
                                                                            8-35

-------
Detroit Traffic Test.   During the later stages of the program, attempts
were made to circumvent the carbon dioxide and water problems by selec-
tively collecting gases only during periods when gas emissions were ex-
pected to be adequate,  such as the fade tests.
8.6   REFERENCES
      (8-1)   S.  G.  Bayer,  T.  A.  Brown,  and R.  D.  Zumwalde, "Equipment and
             Procedures  for Mounting Millipore Filters and Counting
             Asbestos  Fibers  by  Phase Contrast Microscopy," H.E.W. Public
             Health Service,  February 1969.

      (8-2)   R.  E.  Heffelfinger,  C.  W.  Melton, and W.  M.  Henry, "Develop-
             ment  of a Rapid  Survey  Method of  Sampling and Analysis for
             Asbestos  in Ambient  Air,"  Interim Report  to  National Center
             for Air Pollution Control,  July 1970.

      (8-3)   W.  J.  Nicholson, A.  N.  Rohl,  and  E.  F.  Ferrand,  "Air Pollu-
             tion  in New York City," Presented to Second  International
             Air Pollution Conference,  Washington,  D.C.,  December 1970.

      (8-4)   J.  Murchio, Private  Communication, 1971.

      (8-5)   K.  Yada,  "Study  of Chrysotile Asbestos  by a  High Resolution
             Microscope,"  Acta Chrystallegraphica,  Vol. 23,  704 (1967).
8-36

-------
                              SECTION 9

                         VEHICLE TEST RESULTS
9.1   VEHICLE OPERATIONS

      9.1.1   Test Scheduling and Problems Encountered

              Early in the program, it was estimated that approximately
38 days would be required to complete each vehicle test.  This estimate
was based on the optimistic assumption that the vehicle measurements
procedure (take emissions samples, measure wear, inspect system, and
replace worn parts) would require 1.5 days.

              Tables 9-1, 9-2, and 9-3 are the actual versus estimated
test schedules for vehicle tests 1, 2, and 3, respectively.  Vehicle
test 1 took 56 days because of the problems listed.  Moreover, the mea-
surements sequence actually required approximately two days.  In addition,
approximately one-half day was lost per schedule because of rain (the
summer of 1972 was the wettest summer in recent history).  The sum of
the additional one-half day for measurements plus the one-half day for
rain loss gave an average of an additional one day per schedule, or an
additional seven days per vehicle test.  Thus, the addition of seven days
to the estimate of 38 days gave a value of 45 days, achieved in vehicle
tests 2 and 3.

              Near the end of vehicle test 3, there was a very good chance
of finishing in approximately 42-43 days.   However, melting snow and
freezing rain made the driving conditions  hazardous at times.  Thus two
days were lost, and the program was completed just prior to the even more
wintry weather which began in late November in the Detroit area.
              Some of the problems encountered in the program and their
solutions can be summarized as follows:
      •  During the 10-stop fade schedule  of vehicle test 1, the hardened
         steel ring which rotates aginst the Teflon seal slipped from its
         anchored position after shearing  the locking pins.  The leak
         thus created was detected immediately after the fade stops and
         prior to the reburnish.  The ring was reanchored and no further
         problem was encountered during the 15-stop fade or any further
         test schedule.
      •  During the Detroit traffic schedule of vehicle test 1, water
         was  found in the right rear brake collector.  This was pulled
         in through the rotating seal.  This problem was not encountered
         again,  as the vehicle was not operated during heavy rain.
                                                                     9-1

-------
   Table 9-1 - Actual Versus  Estimated Test  Schedules for Vehicle Test 1
TEST
SCHEDULE
Burnish
Measurements*


A. B. Baseline
Measurements
Detroit Traffic
Measurements






10-Stop Face
Reburnish
Measurements



A. F. Baseline
Measurements
15-Stop Fade
Reburnish
Measurements
Final Baseline
Measurements

ESTIMATED
TIME (DAYS)
2.0 , ,
1.5


3-0 , 5
1.5
12.0 ,
1.5 13'5






1.5
1.0 4.0
1.5



3'° 4 5
1.5 ^
1.0
1.0 3.5
1.5
3>° 4 5
1.5 4'5
38.0
ACTUAL TIME (DAYS)
START
5/1



5/11

5/19







6/14





6/22

6/30


7/6


FINISH
5/10



5/18

6/13







6/21





6/29

7/5


7/12


TOTAL
8



6

20







6





6

5


5

56
REMARKS OR PROBLEMS
• Heaters shorted.
• Inverter failed.
• Loose collector screws.
• Slow silicone cure.


• Burned-out heater.
• Water in rear collector
(due to rain).
• Replaced rear seal.
• Burned air line.
• Replaced filters .
• Rain - test stopped.
• Slow silicone cure.
• Rain.
• Slow silicone cure.
• Burned-out T.C.
• Measurements - fronts
only.
• Rotor ring slippage.
• Rain.







«
 Take  emissions samples, measure wear, inspect systems,  replace worn parts,
 9-2

-------
                            Table 9-2 - Actual Versus Estimated Test Schedules for Vehicle Test 2
TEST
SCHEDULE
Burnish
Measurements*
A. B. Baseline
Measurements
Detroit Traffic
Measurements
10-Stop Fade
Reburnish
Measurements
A. F. Baseline
Measurements
15-Stop Fade
Reburnish
Measurements
Final Baseline
Measurements
ESTIMATED
TIME (DAYS)
2'° 3.5
3.0 , _
1.5 4'5
12'° 13 5
1.5 1J>;J
1.5
1.0 4.0
1.5
3.0
1.5 4-5
1.0
1.0 3.5
1.5
3.0 . ,
1.5 4'5
38.0
ACTUAL TIME (DAYS)
START
7/13
7/18
7/24
8/16
8/22
8/30
9/7
FINISH
7/17
7/21
8/15
8/21
8/29
9/6
9/13
TOTAL
4
4
18
4
6
4
5
45
REMARKS OR PROBLEMS


• Rain.
• T/C- replaced.
• Inverter malfunction.

• Rain.
• T/C replaced.

• Lost pressure on llth
circuit. Brake fluid
in collector. Test
terminated.
VO
I
CO
Take emissions samples, measure wear, inspect systems, replace worn parts.

-------
V£>
 I
                           Table 9-3 - Actual Versus Estimated Test Schedules  for  Vehicle Test  3
TEST
SCHEDULE
Burnish
Measurements
A. B. Baseline
Measurements
Detroit Traffic
Measurements
10-Stop Fade
Reburnish .
Measurements
A. F. Baseline
Measurements
15-Stop Fade
Reburnish
Measurements
Final Baseline
Measurements
ESTIMATED
TIME (DAYS)
2'° 3 5
1.5 ^
3<0 4 S
1.5
12.0
1.5 ^'^
1.5
1.0 4.0
1.5
3.0 ,
1.5 'D
1.0
1.0 3.5
1.5
3.0
1.5 *•*
38.0
ACTUAL TIME (DAYS)
START
9/18
9/22

9/29
10/24

10/27

11/3

11/9
FINISH
9/21
9/28

10/23
10/26

11/2

11/8

11/17
TOTAL
4
5

17
3

5

4

7
45
REMARKS OR PROBLEMS
• Rain.









• Freezing rain.
• Icy roads.
                       Take emissions samples, measure wear, inspect systems, replace worn parts.

-------
      •  During  the  final  baseline schedule of vehicle test 2, pressure
        was  lost  for  the  rear brakes and brake fluid was found in the
        collector.  The combined sump and surfaces sample, for the
        eleven  completed  circuits, was salvaged by filtering and re-
        peatedly  washing  the particulates to remove the brake fluid.
        The  linings were  "destroyed" as the fluid could not be removed
        completely.  This problem was not encountered again.

      9.1.2    Mileage  Accumulations

              Table  9-4  lists the mileage accumulations for each schedule.
The A.B. Baseline, A.F.  Baseline, and Final Baseline were run according
to the same schedule,  repeated at different times within the overall
vehicle  test  program.  The average baseline mileages varied from 343 to
348 miles  and the  maximum  variation between vehicle tests was +5.7 percent.
This range for the baseline schedules could also be compared to one-fourth
of the Detroit traffic test for which the average was 352 miles (1408 v 4)
and for  which the  overall  variation was +3.8 percent.  The overall vari-
ation for  the total  mileage accumulation of all three vehicle tests was
very low at +2.4 percent.   These mileage variations were primarily due
to the varying times taken to reach the Detroit traffic circuit.  Normally
only three round trips were required to obtain the twelve circuits.  Rain,
seal failure, thermocouple malfunctions, and other minor difficulties
which required a premature return to base added to the minimum mileage
possible.

      9.1.3    Reporting  of Vehicle Test Data

              The  data for each vehicle test are accumulated in a separate
volume which  includes  a  section for each test sequence:  Burnish; A.B.
(After-Burnish)  Baseline;  Detroit Traffic; 10-Stop Fade; A.F. (After-
Fade) Baseline;  15-Stop  Fade; and Final Baseline.  Each section includes
the following data sheets:  Vehicle Log Sheet; supplementary vehicle
data sheets such as  Detroit Traffic data sheets; Wear Sheet - Front Axle;
Wear Sheet -  Rear  Axle;  Collection of Brake Emissions (Right Side); Col-
lection  of Brake Emissions (Left/Control Side); and Test Summary Sheet.

              The  complete list and examples of each type of data sheet
are included  in  Appendix G.

9.2   PERFORMANCE  OF EMISSIONS COLLECTION SYSTEMS

      9.2.1    Rotating Seal Life
              The  success  of the vehicle tests depended heavily on the
proper operation of  the  rotating seals.  Table 9-5 is a running log of
rotating seal mileages (life) obtained during the vehicle test program.
The original  intent  was  to change the rotating seals at the start of
each test  and prior  to the 10-Stop Fade.  Both premature seal failure
and the  unexpected fact  that disastrous rotating seal wear did not occur
during the fade  led  to abandonment of that plan.
                                                                     9-5

-------
          Table 9-4 - Summary of Vehicle Mileage Accumulations
Schedule
Burnish


A.B.
Baseline

Detroit
Traffic

10-Stop
Fade

A.F.
Baseline

15-Stop
Fade

Final
Baseline

Totals



Test
1
2
3
1
2
3
1
2
3
1
2
3 .
1
2
3
1
2
3
1
2
3
1
2
3

Miles
174
127
100
328
348
368
1439
1430
1355
47
53
58
356
339
347
47
79
52
352
326
352
2756
2702
2632
8090
Average
Miles

134


348


1408


53


347


59


343


2697


Maximum
Deviation

34


20


53


6


9


20


17


65


Percent
Deviation




5.7


3.8





2.6





4.9


2.4


9-6

-------
Table  9-5 - Running Log of  the Rotating Seals Mileages
             Vehicle Test Program
                                                                     Obtained in  the
Test
Schedule
Pre-Test

Burnish


A. B. Baseline

Detroit Traffic



10-Stop Fade


A. F. Baseline


15-Stop Fade

Final Baseline

Total Miles
MK III
Front Collector
Vehicle
Test 1
126

174


328

1431/2059



47


356


47

353/815

2756
Vehicle
Test 2


127


348

1430/1965



53


339/392


12/12
67

326/393

2702
Vehicle
Test 3


100


368

1355



58


347/2664*


52

352/404

2632
MK III
Rear Collector
Vehicle
Test 1


174


328

731/1233
700



47


356


47

353/1515

2756
Vehicle
Test 2


127


348/475

1430



53/1483


339


79

326/744

2702
Vehicle
Test 3


100


368

103/1315
62/62
1190


58/1248


347


52

352/751

2632
Comments

Test 1: OK
Test 2: OK
Test 3: OK
Test 1: OK
Test 2: Rear seal failed and replaced after
475 miles.
Test 3: OK
Test 1: Rear seal replaced after 1233 miles.
Front seal replaced after 2059 miles.
Test 2: OK
Test 3: Rear seal replaced after 103 miles.
Front seal replaced after 62 miles -
"out-of-round. "
Test 1: OK
Test 2: Front seal replaced after 1958 miles.
Rear seal failed and replaced after
1483 miles.
Test 3: OK
Test 1: OK
Test 2: Front seal failed and replaced after
392 miles.
Test 3: Front seal replaced after 2664 miles.
Test 1: OK
Test 2: Front seal failed and replaced after
12 miles.
Test 3: OK
Test 1: Front seal replaced after 815 miles.
Rear seal replaced after 1515 miles.
Test 2: OK, seals used to start Test 3.
Test 3: OK

Includes 393 Miles from Test 2

-------
              Table 9-6 summarizes the rotating seal life  in  miles  ob-
tained for each seal during the three vehicle tests.   These data  were
used to obtain a maximum average life for each rotating  seal.
              Seven rotating seals were used on the front  disc brake
collector.  They were replaced at different mileage accumulations as
follows:
      •  Two seals failed after 12 and 329 miles.

      •  Three seals survived 1965, 2059, and 2664 miles and  were
         replaced as worn, but not failed.
      •  Two seals were used for 815 and 404 miles and were replaced
         although they were not completely worn or failed  after vehicles
         tests 1 and 3, respectively.
              Eight rotating seals were used on the rear drum brake
collector.  They were replaced at different mileage accumulations as
follows:
      •  Three seals failed after 62, 475, and 1483 miles.

      •  Four seals survived 1233, 1515, 1315, and 1248 miles and were
         replaced as worn, but not failed.
      •  One seal survived 751 miles and was removed in  good  condition
         after the third vehicle test.

      9.2.2   Operating Temperatures

      9.2.2.1   Normal Brake Stops

                Throughout the vehicle tests, it was necessary to monitor
the temperatures at all four wheels.  The driver was instructed to take
specified actions when greater than desired temperature  differences
occurred.  For example, during the Detroit Traffic Circuits,  the  maximum
normal operating temperature was 330°F before proceeding.  These  cool-down
periods were seldom necessary.

                The effectiveness of the thermal control aids attached to
the right front brake described in Section 5.5.3 is shown  in  Table 9-7.
The AT = 200 to 250°F shown for the initial burnish was  reduced to a
AT = 115 to 160°F.  Most important was the reduction of  the right front
brake operating temperature from about 400°F to about  300°F.

                Since approximately 90 percent of the  test miles  were
driven on the Detroit Traffic circuit, it was necessary  to monitor  the
temperatures obtained and maintain test reproducibility.   Although  the
temperatures did vary slightly, the normal operating range for the  right
front brake was 260 to 300°F while the normal operating  range for the
right rear brake was 170 to 200°F.  The brake shrouding  did not present
any difficulties on hot days.  Table 9-8 illustrates the brake tempera-
tures measured during four consecutive Detroit Traffic Circuits on  a hot
 9-8

-------
          Table  9-6  -  Rotating  Seal Life (Miles)
VEHICLE
TEST

1

2



3






SEAL
INSTALLATION
1
2
3
4
5
6
5 (cont'd)
6 (cont'd)
7
8
Maximum
Expected
Life (miles)


FRONT DISC BRAKE
Fl 2059
F2 815
F3 1965
F4 392
F5 12
F6 (393)*

F6 2664
F7 404

2059
1965 Average:
2664 2229


REAR DRUM BRAKE
Rl 1233
R2 1515
R3 475
R4 1483
R5 (744)*

R5 1315
R6 62
R7 1248
R8 751
1233
1515
1483 AVi35f:
1315
1248
Continued usage into Vehicle Test No. 3.
                                                               9-9

-------
VO

M
O
                             Table 9-7 - Brake Temperatures During  Burnish Tests  (°F) (Vehicle Test 1)

INITIAL BURNISH
(NO THERMAL CONTROL AIDS)*
After 20 Stops
After 40 Stops
After 60 Stops
RERUN BURNISH
(WITH THERMAL CONTROL AIDS)**
After 10 Stops
After 40 Stops
After 60 Stops
After 80 Stops***
After 100 Stops
After 160 Stops
FRONT DISC BRAKE
Right
(Shrouded)


400
340
360


280
310
265
200
280
300
Left
(OEM Configuration)


150
120
160


150
150
150
130
165
170
AT


250
220
200


130
160
115
70
115
130
REAR DRUM BRAKE
Right
(Shrouded)


255
200
245


205
245
215
160
220
190
Left
(OEM Configuration)


150
110
150


150
165
165
135
170
130
AT


150
90
95


75
80
50
35
50
70
               ***
 Test stopped because of failure of Mk  II rear drum seal.

 Thermal control aids on front wheel plus Mk III rear drum seal.
k
 Start of second day.

-------
Table 9-8 - Brake Temperatures During Detroit Traffic Circuits
            (Vehicle Test 2 - A.B. Baseline)
Location on
Traffic Route
12 Mile and Woodward
Michigan and Third
Adams and Woodward
Adams and Woodward
12 Mile and Woodward
12 Mile and Woodward
Michigan and Third
Adams and Woodward
Adams and Woodward
12 Mile and Woodward
12 Mile and Woodward
Michigan and Third
Adams and Woodward
Adams and Woodward
12 Mile and Woodward
12 Mile and Woodward
Michigan and Third
Adams and Woodward
Adams and Woodward
12 Mile and Woodward

Time of
Day
(July 20, 1972)
6:25 am
6:50
6:59
7:13
7:54
7:54 am
8:37
8:52
9:08
9:48
9:48 am
10:25
10:38
10:49
11:34
1:00 pm
1:42
1:59
2:17
2:50
Ambient
Temp.
°F
75
78
78
79
79
79
80
82
82
84
84
85
85
87
85
90
91
91
91
91
Range (°F)
Front Disc Brake
Right
(Shrouded)
180
260
260
270
270
270
300
300
280
330
330
310
300
280
310
310
320
310
310
300
260-330
Left
(Normal)
130
140
150
150
150
150
160
160
150
190
190
170
170
160
160
210
180
180
170
160
150-210
AT
50
120
110
120
120
120
140
140
140
140
140
140
130
120
150
100
140
130
140
140
110-140
Rear Drum Brake ,/
Right
(Shrouded)
120
150
140
150
150
150
170
180
180
190
190
200
190
180
190
'160
210
210
200
170
140-210
Left
(Normal)
120
140
140
150
150
150
160
160
. 160
160
160
170
140
170
160
160
180
180
170
150
140-180
AT
0
10
0
0
0
0
10
20
20
30
80
30
20
10
30
0
30
30
30
20
10-30

-------
July day with ambient temperatures up to 91°F.  The  At between the
front brakes remained between 110 and 140°F while  that for the rear drum
brakes' remained between 10 and 30°F.
                The temperature trends discussed here were typical for
all three vehicle tests.

      9.2.2.2   Heavy-Duty Fade Stops
                During the Detroit Traffic Test, a series  of stops from
40 mph, in rapid succession, every two blocks caused all  four brakes to
rise in temperature faster than normal.  The shrouded brakes would then
cool slower than the normal brakes during subsequent running.  Conse-
quently, it was anticipated that during the fade tests it  would be
necessary to program the right front disc brake according  to the known
temperature versus stop number for the same friction materials previously
run on an inertia dynamometer and on a normal test vehicle.
                The dynamometer and normal vehicle test baseline results
are given in Figure 9-1.  Two different dynamometer  tests  are included.
The data for the shrouded right front disc brake and the normal left
front disc brake are superimposed on the baseline  results.   After the
7th stop, the time increment was increased for the vehicle test to pre-
vent the right front disc brake from overheating the lining  and creating
an abnormal situation.  The left brake showed a slight temperature reduc-
tion during this increased interval.  The right front brake  was thus
held to the illustrated time-versus-stop curve by  increasing the interval
as necessary.  A temperature of 525°F was recorded as the  temperature before
the 10th stop.  Temperature excursions after the last two  stops were higher
than 540°F.  The recovery stops demonstrated the rate at which the brakes
returned to their normal operating temperatures.

                The data for the rear drum brakes  are also shown in Fig-
ure 9-1.  The shrouded rear drum brake followed the  baseline curve closely.
The left rear drum brake showed a slight temperature reduction with the
increase in interval.  During the recovery stops,  both rear  brakes followed
the baseline cooling curve closer than the corresponding  disc brakes
followed their baseline cooling curve.

                Figure 9-2 shows the corresponding data for  the 15-Stop
Fade schedule.  Baseline data for two inertia dynamometer  tests are also
plotted on the graph.  During the vehicle test, the  shrouded right front
disc brake began to heat more rapidly than expected  (based on the 10-stop
fade experience) and the increased interval for cooling between stops
was first necessary after the 5th stop.  Additional  increased intervals
were then necessary after each succeeding stop.  Consequently, the left
front disc brake never did increase above 300°F.   A  temperature of 575°F
was recorded as the temperature before the 15th stop.   Temperature excur-
sions after the last 6 stops were higher than 600°F.
9-12

-------
  FRONT BRAKES
   600


   500- -


TT  400--
u
CC
DC
UJ
1
UJ
   300-
200--
    100- -
                     FIRST
                     INCREASED
                     INTERVAL
             VEHICLE
         O  BASELINE
         A  RIGHT
         D  LEFT
                                8    10
                                                               8     10    12
  REAR BRAKES
   600--


   500- -


   400 - -
HI
CC
cc
LU
a.
   300--
   200-
    100- -
                   FIRST
                   INCREASED
                   INTERVAL
      f
                468
                    FADE
                                     10     2


                                    STOP NUMBER
46     8     10    12
     RECOVERY
     Figure 9-1 - Brake  Temperature  Data - Vehicle Test  1,  10-Stop Fade
                                                                          9-13

-------
 FRONT BRAKES:

    600-r
    500 +
cc
    400 +
    300 -h
CC
Ul
o.

LLJ   200
    100-
FIRST
INCREASED
INTERVAL
         DYNAMOMETER
O  BASELINE
A  RIGHT
D  LEFT
                               8     10    12     14
                                                                        8     10
                                                                                   12
  REAR BRAKES:
    600-
   500
o_   400 -|-
LU
cc
D
<   300-
cc
LU
a.

I"   200-
    100
FIRST
INCREASED
INTERVAL
                                                14
        6     8    10    12
            FADE
                        STOP NUMBER
                                                                  6     8
                                                                 RECOVERY
          10    12
      Figure 9-2  - Brake Temperature  Data  - Vehicle Test 1,  15-Stop Fade
   9-14

-------
                The long time period at which the brakes were above 500°F
produced  an  additional effect within the shrouded brake.  The heat gener-
ated at the  rotor/pad interfaces was retained within the shroud and caused
the brake fluid within the right front caliper to heat.  The resultant'
boiling of fluid produced a "loss of brake pedal" for the 14th and 15th
stops;  the brakes bottomed out, and pumping the brakes did not restore
adequate  line  pressure to maintain the planned deceleration.
                The recovery data illustrate the rate at which the
shrouded  brakes recovered from the high-temperature testing.  The fluid
boil (soft pedal) persisted through the first eight recovery stops until
the indicated  lining temperature of the shrouded brake fell below 400°F.
This behavior  demonstrates the effectiveness of air cooling in keeping
brake temperature low on normal unshrouded brakes.
                The data for the drum brakes are also illustrated in
Figure 9-2.  The increased interval early in the test sequence held the
temperatures lower than for the baseline data.

                The temperature trends discussed for the fade schedules
were typical for all three vehicle tests.

      9.2.3    Collection Efficiencies

      9.2.3.1    Recovery of Brake Particulate Emission
                The weights of brake particulate wear debris collected
during vehicle tests 1, 2, and 3 are given in Tables 9-9, 9-10, and 9-11,
respectively.

                For the right front disc brake, the surface sample has
the largest  weight of the three samples taken.  The sump and airborne
samples are  comparable in weight.  For the left front brake, the sump
sample was comparable in weight to the right front brake.  Moreover the
total weight of the samples taken from the left front brake of vehicle
tests 1 and  2  were comparable when added for each schedule to arrive
at a total weight for the entire vehicle test.  On the other hand, the
cumulative sample taken for all of the vehicle test 3 was significantly
less.

                For the right rear drum brake, the surfaces sample has
the largest  weight of the three samples taken.  The sump and the airborne
samples are  comparable in weight.  In some instances, the results for the
sump value were reported negative.  This occurred because of the 80 per-
cent return  of material to the sump from each preceding schedule.  No
negative  values occurred during the normal driving up to the end of the
Detroit Traffic Test schedule.   During the more severe fade tests, some
of the 80 percent return was redistributed to the surfaces samples.  The
overall wear debris from each wheel did, however, have a positive weight
gain.
                                                                    9-15

-------
     Table 9-9  - Weights  of  Brake Particulate Wear Debris Collected
                 (Vehicle Test 1) (gm)
Schedule
Burnish
A.B.
Baseline
Detroit
Traffic
10 Stop
Fade
A.F.
Baseline
15 Stop
Fade
Final
Baseline
Totals

Collector
Sump
Surfaces
Airborne
Sump
Surfaces
Airborne
Sump
Surfaces
Airborne
Sump
Surfaces
Airborne
Sump
Surfaces
Airborne
Sump
Surfaces
Airborne
Sump
Surfaces
Airborne
Sump
Surfaces
Airborne
Entire
Test
Front Brakes
Right
(Shrouded)
0.142
0.412
0.061
0.083
0.644
0.130
0.201
2.010
0.237
0.580
1.212
0.013
0.191
1.764
0.259
0.616
5.943
0.120
0.154
2.011
0.375
0.967
13.996
1.195
17.158
Left
(Normal)
0.116*
0.029
0.128
0.055
0.458
0.109
0.244
0.076
0.153
0.030
0.150
0.027
0.138
0.083
1.387
0.409
1.796
Rear Brakes
Right
(Shrouded)
0.144
1.170
0.046
0.185
0.590
0.049
0.436
4.052
0.285
-0.335
0.371
0.017
0.060
0.652
0.030
-0.046
0.100
0.004
0.097
0.440
0.003
0.541
7.375
0.434
8.350
Left
(Normal)
0.220
0.394
0.208
0.205
1.654
0.878
1.120
0.275
-0.516
1.543
-0.330
0.169
0.017
0.448
2.373
3.912
6.285
  *Estimated from cumulative sample  (0.145  gm)  taken during this
   schedule only.                                          6
9-16

-------
 Table 9-10 - Weights of Brake Particulate Wear Debris Collected
              (Vehicle Test 2) (gm)
Schedule
Burnish
A.B.
Baseline
Detroit
Traffic
10 Stop
Fade
A.F.
Baseline
15 Stop
Fade
Final
Baseline
Totals

Collector
Sump
Surfaces
Airborne
Sump
Surfaces
Airborne
Sump
Surfaces
Airborne
Sump
Surfaces
Airborne
Sump
Surfaces
Airborne
Sump
Surfaces
Airborne
Sump
Surfaces
Airborne
Sump
Surfaces
Airborne
Entire
Test
Front Brakes
Right
(Shrouded)
0.109
0.432
0.039
0.049
0.481
0.015
0.042
2.828
0.106
0.170
1.437
0.023
0.098
1.114
0.107
0.098
2.205
0.099
0.051
1.193
0.138
0.555
9.690
0.527
10.772
Left
(Normal)
0.122
0.032
_
0.343
0.126
0.128
0.055
0.084
0.036
0.084
0.049
0.111
0.141
0.984
0.439
1.423
Left Brakes
Right
(Shrouded)
0.105
0.166
0.004
0.081
0.596
0.007
1.247
4.159
0.056
-0.217
1.322
0.010
-0.047
0.749
0.004
-0.047
0.181
0.008
0.260*
1.070*
0.011
0.941
8.293
0.104
9.288
Left
(Normal)
-0.132
0.157
0.109
0.166
0.955
0.769
-0.597
0.290
-0.255
0.328
-0.255
0.360
0.295
0.172
0.637
2.242
2.879
Value may be  in error because  of  brake fluid in collector during
Final Baseline schedule.
                                                                9-17

-------
   Table 9-11 - Weights of Brake Particulate Wear Debris Collected
                (Vehicle Test 3) (gm)
SCHEDULE
Burnish
A.B.
Baseline
Detroit
Traffic
10 Stop
Fade
A.F.
Baseline
15 Stop
Fade
Final
Baseline
Totals

COLLECTOR
Sump
Surfaces
Airborne
Sump
Surfaces
Airborne
Sump
Surfaces
Airborne
Sump
Surfaces
Airborne
Sump
Surfaces
Airborne
Sump
Surfaces
Airborne
Sump
Surfaces
Airborne
Sump
Surfaces
Airborne
Entire
Test
FRONT BRAKES
RIGHT
(SHROUDED)
0.121
0.408
0.045
0.266
1.097
0.138
0.208
3.773
0.495
0.438
0.515
0.188
0.033
1.389
0.328
0.391
3.075
0.402
0.105
2.860
0.337
1.562
13.117
1.933
16.612
LEFT
(NORMAL)
Cumulative
Sample





1





'
0.182
0.169
0.351
REAR BRAKES
RIGHT
(SHROUDED)
0.319
2.056
0.033
0.215
1.234
0.052
0.379
1.154
0.027
0.151
0.248
0.015
0.118
0.295
0.050
0.088
0.184
0.018
0.246
2.288
0.017
1.516
7.459
0.212
9.187
LEFT
(NORMAL)
Cumulative
Sample





i





'
0.974
1.908
2.882
9-18

-------
      9.2.3.2   Mass Balance

      £.2.3.2.1   Amount  of  Emissions

                 The  initial weights of the brake friction material and
the weight  losses per  wheel  are given in Table 9-12.  The weights of the
particulates collected (Tables 9-9,  9-10, and 9-11) and the data in
Table 9-12  were used to calculate the mass balances given in Tables 9-13,
9-14, and 9-15  (numbers not  in parentheses).

                 The  right  front brake data ranged from approximately
42 percent  recovery in the initial tests to approximately 70 percent in
the later tests.  The  low initial recovery may have been due to excess
gassing of  the  green linings resulting in a lower recovery as particu-
lates.  This condition changed as the linings became burnished to a
greater extent  and the frictional heat-affected layer contained more
inorganic content.  The recovery for the 10-stop fade of vehicle tests 1
and 3 were  low  as the  debris was "tarry" and the surfaces fraction could
be collected only with difficulty.  The recovery for the 15-stop fade
of vehicle  tests 1 and 3  was somewhat low, possibly for the same reason.
                 The  left front brake showed the same basic trends as
the right front brake, increasing throughout the vehicle tests where
normal driving was carried out.  During the two fade tests and after
fade and Final Baseline,  approximately 2 to 3 times more wear debris
remained in the unshrouded brake.  This may have been due to the high
concentration of wear  debris produced, which in turn was scraped into the
rivet holes during the braking.
                 The  material recovery totals for the rear brakes show
wide variations.  The  problem, in part, was due to the carryover from
test-to-test of the sump  debris, 80 percent of which was returned to the
brake after each test  schedule.  The data can be explained partially
by examination  of the  distribution of particulate emissions obtained at
each sample location.

      9.2.3.2.2   Distribution of Emissions
                 The  data given in parentheses in Tables 9-13, 9-14,
and 9-15, represent the percent of total particulates collected - the
distribution of the particulate emissions.  The bottom portion of Tables
9-13, 9-14, and 9-15,  shows  the ranges for the distribution into sump,
surface, and airborne  samples.
                 The  data for the rear brakes fell into fairly narrow
ranges for  the first three schedules only.  From the 10-Stop Fade to
the Final Baseline, the data show both negative recoveries and greater
than 100 percent recoveries.  For both the 10- and 15-Stop Fade schedules
of vehicle  test 1, the negative recovery figures were not reflected by
corresponding increases in the surface or airborne figures.  However, the
reverse situation prevailed  in vehicle test 2 for the 10-Stop Fade and
the ensuing A.F. Baseline.
                                                                    9-19

-------
VO
                               Table  9-12  -  Brake  Friction Material Initial Weights and Weight
                                            Losses (gm)



en
01
CO
CO
o
,J
4J
,e
00
•H
01
01
4J
Ml
•H
3
Initial
Duty

Moderate

Heavy
to
Abusive
Cumulative

As
Prepared

Schedule
Burnish
A. B. Baseline
Detroit Traffic
Totals
10-Stop Fade
A. F. Baseline
15-Stop Fade
Final Baseline
Totals
Total Wear
Inner
Outer
Primary
Secondary
Totals
Vehicle Test 1
Front
Right
1.48
1.86
5.64
8.98
5.72
3.34
11.87
3.73
24.66
33.64
95.8
117.4


213.2
Left
0.96
1.29
4.17
6.42
0.78
1.14
0.50
1.22
3.64
10.06
93.8
116.5


210.3
Rear
Right
3.33
0.92
5.80
10.05
0.45
1.02
0.29
0.49
2.25
12.30


108.1
189.6
297.7
Left
1.35
1.21
4.96
7.52
0.67
2.39
0.25
1.13
4.44
11.96


106.4
189.3
295.7
Vehicle Test 2
Front
Right
1.45
1.15
4.11
6.71
2.69
2.87
3.62
1.89
11.07
17.78
106.4
105.0


211.4
Left
0.94
1.11
3.53
5.58
1.58
1.28
0.49
0.68
4.03
9.61
106.1
105.6


211.7
Rear
Right
0.66
1.21
5.31
7.18
1.01
0.28
0.35
1.57
3.21
10.39


104.9
181.3
286.2
Left
0.79
1.17
4.16
6.12
0.54
0.95
0.55
0.83
2.87
8.99


102.4
180.2
282.6
Vehicle Test 3
Front
Right
1.32
2.81
5.02
9.15
4.44
2.11
7.79
4.14
18.48
27.63
115.3
152.3


267.6
Left
0.62
1.39
5.05
7.06
0.82
1.17
0.72
2.44
5.15
12.21
113.0
160.3


273.3
Rear
Right
3.11
1.89
1.83
6.83
1.22
0.61
1.20
1.19
4.30
11.13


113.2
153.5
266.7
Left
3.06
0.80
4.67
8.53
1.90
1.34
0.80
1.45
5.49
14.02


113.7
167.7
280.4

-------
     Table 9-13 - Material Percent Recovery as Particulate  Emissions
                  (Vehicle Test  1)
SCHEDULE
Burnish
A.B.
Baseline
Detroit
Traffic
10 Stop
Fade
A. F.
Baseline
15 Stop
Fade
Final
Baseline
Ranges
COLLECTOR
Sump
Surfaces
Airborne
Total
Sump
Surface
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
FRONT BRAKES
RIGHT
(SHROUDED)
(24)* 10
(67) 28
(9) 4
42
(11) 5
(24) 34
(15) 7
45
(10) 4
(81) 35
(9) 4
43
(31~) 10
(63+) 20+
(6-) 2
32+
(9) 6
(79) 52
(12) 8
66
(9) 5
(89) 50
(2) 1
56
(6) 4
(79) 54
(15) 10
68
( 6-31)
(63-89)
( 2-15)
LEFT
(NORMAL)
(81) 9
(19) 2
U
(71) 10
(29) 4
14"
(79) 11
(21) 3
14
(76) 31
(24) 10
41
(81) 13
(19) 3
16"
(88) 30
(17) 6
36
(61) 11
(39) 7
18"
(61-83)
(17-39)

REAR BRAKES
RIGHT
(SHROUDED)
(10) 4
(87) 36
(3) 1
41
(22) 20
(72) 65
(6) 5
90
(9) 7
(85) 70
(6) 5
82
-75
83
4
12
(8) 6
(88) 64
(4) 3
73
-16
35
1
20
20
90
1
111
( 8-22)
(72-88)
( 3-6)
LEFT
(NORMAL)
(36) 16
(64) 29
4l
(51) 17
(49) 16
33"
(65) 33
(35) 18
5l
166
41
207
-22
65
~43~
-133
68
-65
1
40
4l
(36-65)
(35-65)

*Numbers in parenthesis  are  percents of total particulates collected: 10/42 = 24%

 Not all of the sample was recovered.
                                                                       9-21

-------
      Table 9-14 -  Material Percent Recovery as Particulate Emissions
                    (Vehicle Test  2)
SCHEDULE
Burnish
A.B.
Baseline
Detroit
Traffic
10 Stop
Fade
A.F.
Baseline
15 Stop
Fade
Final
Baseline
Ranges
COLLECTOR
Sump
Surfaces
Airborne
Total
Sump
Surface
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
FRONT BRAKES
RIGHT
(SHROUDED)
(20)* 8
(73) 30
(7) 3
41
(7) 4
(71) 41
(22) 13
58
(2) 1
(93) 65
( 5) 3
69
(10) 6
(88) 33
(2) 1
60
(2) 1
(89) 39
(9) 4
44
(5) 3
(90) 61
(5) 3
67
(4) 3
(86) 63
(10) 7
73
(2-20)
(71-93)
(2-22)
LEFT
(NORMAL)
(81) 13
(10) 3
16
Not
Sampled
(72) 10
(28) 4
14"
(72) 8
(28) 3
n
(83) 15
(17) 3
18
(63) 17
(37) 10
IT
16
21
IT
(63-83)
(17-37)
REAR BRAKES
RIGHT
(SHROUDED)
(38) 16
(60) 25
(2) 1
42
(12) 7
(86) 49
(2) 1
57
(22) 23
(77) 78
(1) 1
102
-22
131
1
111
-181
267
1
87
-13
52
2
41
Brake
Fluid
in Linings
(12-22)
(60-86)
(1-2)
LEFT
(NORMAL)
-17
20
~
(39) 9
(61) 14
23
(56) 23
(44) 18
41
-110
54
^56"
(44) 28
(56) 35
63
-46
65
19
(63) 36
(37) 21
57
(39-63)
(37-61)
*Numbers in brackets are percents of total particulates collected: 8/41 =  20%
 9-22

-------
    Table 9-15  - Material Percent Recovery as Particulate Emissions
                  (Vehicle Test 3)
SCHEDULE
Burnish
A.B.
Baseline
Detroit
Traffic
10 Stop
Fade
A.F.
Baseline
15 Stop
Fade
Final
Baseline
Ranges
COLLECTOR
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
FRONT BRAKES
RIGHT
(SHROUDED)
(21)* 9
(72) 31
(7) 3
43
(19) 10
(72) 39
(9) 5
54
(5) 4
(85) 75
(11) 10
89
(38) 10
(46) 12
(16) 4
26
(2) 2
(79) 66
(19) 16
84
(20) 10
(70) 34
(10) 5
49
(4) 3
(86) 69
(10) 8
80
( 2-38)
(46-86)
( 7-19)
LEFT
(NORMAL)
Cumul
Sam




1
ative
pie




r
(52) 1.5
(48) 1.4
~3~

REAR BRAKES
RIGHT
(SHROUDED)
(13) 10
(83) 66
(4) 3
79
(9) 7
(87) 65
(4) 3
75
(25) 21
(74) 63
(1) 1
85
(36) 12
(61) 20
(3) 1
33
(25) 19
(64) 48
(11) 8
75
(32) 7
(64) 14
(4) 1
22
H20
in
Linings
( 9-36)
(61-87)
( 1-11)
LEFT
(NORMAL)
Cumul
Sam




1
ative
pie




f
(34) 9
(66) 17
26"

*Numbers in brackets are percents of total particulates  collected.
                                                                        9-23

-------
                  The ranges for the sump, surfaces,  and  airborne samples
given at the bottom of all three tables agreed rather well  for all brakes
irregardless of the brake friction materials used or  the  rotor conditions
prior to the start of the test.

9.3   PERCENT ASBESTOS CONTENTS

      9.3.1   Program Results
              The microscopy results were converted by  the  computer into
the asbestos emissions results summarized in Tables 9-16, 9-17,  and 9-18.
              For vehicle test 1, the range of asbestos contents  in brake
emissions varies from a high of 1.65 percent down to  a  low  of  0.05  per-
cent.  Of the 47 analyses reported, only two were above 1.00 percent.
The overall average was 0.38 percent.
              For vehicle test 2, the range of asbestos contents  in brake
emissions varies from a high of 1.42 percent down to  a  low  of  0.03  per-
cent.  Of the 43 analyses reported, only one was above  1.09 percent, and
only three were in the range 0.50 to 0.96 percent; all  others  were  less
than 0.50 percent.  The overall average, was 0.25 percent.

              For vehicle test 3, the range of asbestos content  in  brake
emissions varies from a high of 0.51 percent down to  a  low  of  0.003 per-
cent.  Of the analyses reported, three were in the range  0.20  to  0.51 per-
cent; all others were less than 0.20 percent.  The overall  average  was
0.07 percent.

              For all three vehicle tests, the overall  average of asbestos
content in the brake emissions was 0.23 percent.  The following  trends
were noteworthy:

      •  The right front disc brake yielded higher asbestos contents
         than the right rear drum brake (for two of the three  vehicle
         tests):

              Vehicle Test     R.F. Disc (%)     R.R. Drum  (%)

                   1               0.45               0.30
                   2               0.26               0.24

                   3               0.07               0.07
      •  In^general, the airborne samples contained a lower asbestos
         weight percent than the corresponding sump and surfaces  samples.
      •  In general, the asbestos weight percent in brake emissions was
         higher when the materials were new; the asbestos content de-
         creases with brake use.

      •  For all vehicle tests, the asbestos weight percent increased
         only slightly for the severely burnished brakes  during  the
         fade tests.
9-24

-------
Table 9-16 - Summary of Asbestos Analytical Results (Vehicle Test 1)
             (Weight Percent)
Schedule
Burnish
A.B.
Baseline
Detroit
Traffic
10-Stop
Fade
A.F.
Baseline
15-Stop
Fade
Final
Baseline

Collector
Sump
Surfaces
Airborne
Sump
Surfaces
Airborne
Sump
Surfaces
Airborne
Sump
Surfaces
Airborne
Sump
Surfaces
Airborne
Sump
Surfaces
Airborne
Sump
Surfaces
Airborne
Average
Front Brakes
Right
(Shrouded)
0.813
0.398
0.144
(0.452)*
1.650
0.472
0.290
(0.804)
0.247
0.137
0.052
(0.145)
0.463
0.162
0.154
(0.260)
0.656
0.507
0.134
(0.432)
0.602
1.548
0.175
(0.775)
0.435
0.290
0.167
(0.297)
0.452
Left
(Normal)
Not
Anal





)
**
yzed





i
Average
Rear Brakes
Right
(Shrouded)
0.865
0.349
(0.607)
0.179
0.415
0.493
(0.362)
0.129
0.373
0.092
(0.198)
0.280
0.071
0.132
(0.161)
0.419
0.242
0.079
(0.247)
0.071
0.257
0.222
(0.183
0.585
0.324
0.145
(0.351)
0.301
Left
(Normal)
No
Anal
1
0.
0.
0.
0.
t
yzed
t
991
265
275
416
Not
Analyzed
0.
0.
439
472
Not
Analyzed

 *Average  value  for  wheel where collection took place.
**Not Analyzed - indicates that analysis was not required.
                                                                  9-25

-------
  Table 9-17 - Summary of Asbestos Analytical Results (Vehicle Test 2)
               (Weight Percent)

SCHEDULE

Burnish



A.B.
Baseline


Detroit
Traffic


10-Stop
Fade


A.F.
Baseline


15-Stop
Fade


Final
Baseline


COLLECTOR

Sump
Surfaces
Airborne

Sump
Surfaces
Airborne

Sump
Surfaces
Airborne

Sump
Surfaces
Airborne

Sump
Surfaces
Airborne

Sump
Surfaces
Airborne

Sump
Surfaces
Airborne
Average
FRONT BRAKES
RIGHT
(SHROUDED)
0.402
0.968
0.186
(0.515)*
0.236
0.311
0.211
(0.253)
0.304
0.548
0.234
(0.362)
0.244
0.261
0.107
(0.260)
0.443
0.173
0.165
(0.260)
0.119
0.193
0.095
(0.136)
0.117
0.071
0.032
(0.073)
0.258
LEFT
(NORMAL)
Not
Analyzed






















i






















r
Average
REAR BRAKES
RIGHT
(SHROUDED)
0.484
1.416
0.087
(0.636)
0.268
0.098
0.344
(0.237)
0.249
0.113
0.115
(0.159)
0.199
0.619
0.194
(0.185)
0.138
0.237
0.180
(0.185)
0.065
0.136
0.048
(0.083)
0.058
0.067
(0.063)
0.243
LEFT
(NORMAL)
Not
Analyzed






















i






















r

  *Average value for wheel where collective took place.
9-26

-------
Table 9-18 - Summary of Asbestos Analytical Results (Vehicle Test 3)
             (Weight Percent)

SCHEDULE

Burnish



A.B.
Baseline


Detroit
Traffic


10-Stop
Fade


A.F.
Baseline


15-Stop
Fade

Final
Baseline




COLLECTOR

Sump
Surfaces
Airborne

Sump
Surfaces
Airborne

Sump
Surfaces
Airborne

Sump
Surfaces
Airborne

Sump
Surfaces
Airborne

Sump
Surfaces
Airborne
Sump
Surfaces
Airborne

Average
FRONT BRAKES
RIGHT
(SHROUDED)
0.218
0.101
0.099
(0.109)*
0.106
0.024
0.125
(0.085)
0.018
0.013
0.025
(0.019)
0.045
0.041
0.055
(0.047)
0.158
0.073
0.047
(0.093)
0.109
0.047
0.035
(0.064)
0.089
0.087
0.037
(0.071)
0.070
LEFT
(NORMAL)
Cumulative
Sample




















i




















'
Not
Analyzed


Average
REAR BRAKES
RIGHT
(SHROUDED)
0.063
0.046
0.060
(0.056)
0.063
0.056
0.044
(0.054)
0.046
0.057
0.037
(0.047)
0.102
0.055
0.014
(0.057)
0.034
0.022
0.003
(0.019)
0.065
0.025
0.014
(0.035)
0.512
0.237
0.035
(0.261)
0.074
LEFT
(NORMAL)
Cumulative
Sample




















1




















1
0.026
0.031
-
-

*Average value  for  wheel where collection took place.
                                                                 9-27

-------
       •   The  data  for vehicle  test  2  showed slightly lower emissions
          than for  vehicle  test 1  (Test  2  started with smoother used rotor
          surfaces. )

       9.3.2    Battelle Analyses

               The  contractual  requirements  for the asbestos particle size
 distribution  in addition to the asbestos  content placed undue burden on
 the accuracy  of the asbestos content  calculation.   To provide a systematic
 independent check  on the asbestos emissions analyses, the EPA Project
 Officer  arranged a second  contract  for  Battelle Columbus Laboratories
 to  analyze 24 samples generated by  the  program.   The analytical method
 used by  Battelle was developed for  EPA  under a separate contract.   The
 method is outlined in Appendix H.
               The  Battelle results  are  given in Appendix H.  Mr.  Carl
 Melton was the Battelle Technical Contact.

       9.3.3    Johns-Manville Analyses

               During the course of  the  program,  Johns-Manville volunteered
 to  analyze three samples from  the program using  an analytical procedure
 which  they had developed for the determination of  low asbestos contents
 in  brake wear debris.  Drs. Sidney  Spiel and James Leineweber conducted
 these  tests.   The  results are  given in  Appendix  H.

       9.3.4    Comparison of Asbestos Analytical  Results

               Table 9-19 gives the comparative data for the asbestos
 analytical results obtained by the program,  Battelle,  and Johns-Manville.
 The three Johns-Manville results agreed with the Battelle data as  expected.

               In 19 of the 24 analyses, the  program results were higher
 for asbestos  percent than the  corresponding  data from Battelle.  The  five
 Battelle results that were larger than  the  corresponding program results
 were larger by the following factors:   7.5,  2.6, 2.1,  2.1,  and 1.2.
 There  were three program results larger than the corresponding Battelle
 results  by a  factor of less than 1.5.   Of the  remaining 16  comparative
 sets of  data,  two program results were  greater by  a factor  in the  range
 1.5 to 2.5, eight program results were  greater by  a factor  in the  range
 2.5 to 10, and six program results were greater  by  a factor in the range
 10  to  100.  The program average was 0.25 percent, while the Battelle
 average  was 0.17 percent, or 68 percent of the Program average.

               The program data were expected  to  be  higher for the  follow-
 ing reasons :

       •  All  fibers found were assumed  to be  cylinders of projected
         diameter  and length as indicated by microscopy.  A fiber  with
         an elliptical cross section will actually  be  smaller in volume
         than that reported.
                               aSSUmed to be 10° Percent asbestos.  Par-
                degraded asbestos fibers are similar to asbestos  and were
         counted.  Thxs is especially true for the larger fibers.
9-28

-------
                                   Table 9-19  - Comparison of Analytical Results  for  Asbestos

Vehicle
Test 1
Vehicle
Test 2
Vehicle
Test 3

Schedule
Detroit
Traffic
10-Stop
Fade
Burnish
Detroit
Traffic
Detroit
Traffic
Collector
Sump
Surfaces
Airborne
Sump
Surfaces
Airborne
Sump
Surfaces
Airborne
Sump
Surfaces
Airborne
Sump
Surfaces
Airborne
Averages
Front Disc Brakes
Program
0.247
0.137
0.052
0.463
0.254
0.402
0.186
0.304
0.234
0.018
0.025
0.204
JM
0.005
-
-
—
-
-
Battelle
0.21
0.011
0.001
1.22
0.31
0.28
0.10
0.62
0.006
0.135
0.016
0.265
Rear Drum Brakes
Program
0.129
0.373
0.092
0.280
0.132
0.484
1.416
0.249
0.113
0.115
0.046
0.037
0.289
JM
0.002
0.006
—
—
-
-
-
Battelle
0.025
0.006
0.001
0.22
0.007
0.10
0.38
0.057
0.061
0.015
0.010
0.044
0.077
Clutch
Program
0.291
-
-
-
-
-
Battelle
0.007
-
-
-
~
-
VO


VO
                     Program Average:   0.25
                     Battelle Average:  0.17
                              Ratio:   Battelle/Program =0.69

-------
      •  Other analytical techniques rely on reducing all asbestos to
         its fibril nature where dimensions and  structure are well
         characterized.  At the same time, all olivine and partially
         degraded asbestos are mechanically reduced  to a nonfibrous
         nature so that only the stronger asbestos fibrils that  remain
         are counted.

9.4   ASBESTOS EMISSIONS FACTORS
      To compare the generation of asbestos emissions  properly on a
mass-weighted basis, it was found necessary to calculate the  asbestos
emissions factors in weight and in weight per mile.   These weights of
asbestos emissions were obtained by multiplying  the  weight of brake wear
debris generated (Tables 9-9, 9-10, or 9-11) by  the  appropriate  asbestos
percent determined for that weight of debris produced  (Tables 9-16,  9-17,
or 9-18).  These data are expressed in mg in Tables  9-20,  9-21,  and 9-22.

      Example:

              Vehicle Test 2
              Burnish

              Right Front Brake ^      Sample
              Sump
      From Table 9-10:

              Weight of sample collected:        0.109  gm
      From Table 9-17:

              Asbestos weight percent:            0.402
      Data given in Table 9-21:

              0.10 gm x 1000 2S. x 0.00402 = 0.438 mg
                             gm                    &

Using the mileages reported in Table 9-4, the asbestos emission  in Mg per
mile are given in Tables 9-23, 9-24, and 9-25.
      Example:

              Sample same as that used in above example.
      From Table 9-21:

              Asbestos weight produced for entire test:  0.438 mg
      From Table 9-4:

              Mileage for Burnish Sequence of vehicle  test  2:  127 miles
      Data given in Table 9-24:
              0.438 mg x 1000 M v 127 miles = 3.45 yg/mlle
9-30

-------
Table 9-20 - Weight of Asbestos Generated During Braking
             (Vehicle Test 1) (mg)
SCHEDULE
Burnish
A.B.
Baseline
Detroit
Traffic
10-Stop
Fade
A.F.
Baseline
15-Stop
Fade
Final
Baseline
COLLECTOR
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
FRONT BRAKES
RIGHT
(SHROUDED)
1.160
1.640
0.088
2.888
0.137
0.340
0.377
0.854
0.497
2.754
0.123
3.374
2.685
1.963
0.080
4.728
1.253
8.943
0.347
10.543
3.708
91.998
0.210
95.916
0.670
8.748
0.626
10.044
LEFT
(NORMAL)
No
Anal1





i
t
yzed





r
REAR BRAKES
RIGHT
(SHROUDED)
N/A
10.121
0.161
10.282
0.331
2.449
0.242
3.022
0.562
15.114
0.262
15.938
1.039
0.022
1.061
0.251
1.578
0.024
1.853
0.257
0.009
0.266
0.567
1.426
0.004
1.997
LEFT
(NORMAL)
No
Anal
1
16.
2.
18.
3.
1.
4.
t
yzed
p
350
315
665
180
143
323
Not
Analyzed
0.
0.
798
798
Not
Analyzed
                                                            9-31

-------
        Table 9-21 - Weight of Asbestos Generated During Braking
                     (Vehicle Test 2) (mg)
SCHEDULE
Burnish
A.B.
Baseline
Detroit
Traffic
10-Stop
Fade
A.F.
Baseline
15-Stop
Fade
Final
Baseline
COLLECTOR
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
FRONT BRAKES
RIGHT
(SHROUDED)
0.438
4.190
0.026
4.654
0.116
1.495
0.032
1.643
0.127
15.620
2.510
18.237
0.415
3.755
0.024
4.194
0.160
1.932
0.177
2.269
0.117
4.250
0.094
4.461
0.051
0.851
0.044
0.946
LEFT
(NORMAL)
Nc
Anal





i
>t
.yzed





1
REAR BRAKES
RIGHT
(SHROUDED)
0.508
2.350
0.035
2.893
0.217
0.584
0.028
0.829
3.108
4.705
0.064
7.877
-0.430
8.190
0.019
7.779
-0.672
1.775
0.007
1.110
-0.031
0.246
0.004
0.229
0.847
0.074
0.921
LEFT
(NORMAL)
Nc
Ana!





\
)t
Lyzed






9-32

-------
Table 9-22 - Weight of Asbestos Generated During Braking
             (Vehicle Test 3) (mg)
SCHEDULE
Burnish
A.B.
Baseline
Detroit
Traffic
10-Stop
Fade
A.F.
Baseline
15-Stop
Fade
Final
Baseline
COLLECTOR
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
T otal
Sump
Surfaces
Airborne
Total
FRONT BRAKES
RIGHT
(SHROUDED)
0.264
0.412
0.045
0.721
0.282
0.263
0.173
0.718
0.037
0.490
0.124
0.651
0.197
0.211
0.103
0.511
0.052
1.014
0.154
1.220
0.426
1.445
0.141
2.012
0.093
2.488
0.125
2.706
LEFT
(NORMAL)
Cumul
Sam




1
ative
pie




r
Not
Analyzed
REAR BRAKES
RIGHT
(SHROUDED)
0.201
0.946
0.020
1.167
0.135
0.691
0.023
0.849
0.174
0.658
0.010
0.842
0.154
0.136
0.002
0.292
0.040
0.065
0.002
0.107
0.057
0.046
0.003
0.106
1.260
5.422
0.006
6.688
LEFT
(NORMAL)
Cumul
Sam




1
ative
pie




\
0.253
0.591
0.844
                                                            9-33

-------
        Table 9-23 - Weight  of  Asbestos  Generated During Braking
                     (Vehicle Test  1)  (yg/mile)
Schedule
Burnish
A.B.
Baseline
Detroit
Traffic
10-Stop
Fade
A.F.
Baseline
15-Stop
Fade
Final
Baseline
Collector
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Front Brakes
Right
(Shrouded)
6.77
9.42
0.51
16.70
0.04
1.04
1.15
2.23
0.35
1.91
0.09
2.35
57.13
41.77
1.70
100.60
3.52
25.12
0.97
29.61
78.89
1957.40
4.47
2040.76
1.90
24.85
1.78
28.53
Left
(Normal)
No
Ana]





,
t
yzed





r
Rear Brakes
Right
(Shrouded)
N/A
58.11
0.92
59.09
1.01
7.47
0.74
9.22
0.39
10.50
0.18
11.07
22.11
0.47
22.58
0.71
4.43
0.07
5.21
5.47
0.19
5.66
1.61
4.05
0.01
5.67
Left
(Normal)
Nc
Ana!
\
)t
.yzed
1
13.52
1.61
14.13
67.85
24.35
92.20
No
Anal

i
t
yzed

>
9-34

-------
N
Table 9-24 - Weight of Asbestos Generated During Braking
             (Vehicle Test 2) (yg/mile)

SCHEDULE

Burnish



A.B.
Baseline


Detroit
Traffic


10-Stop
Fade


A.F.
Baseline


15-Stop
Fade


Final
Baseline



COLLECTOR

Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
FRONT BRAKES
RIGHT
(SHROUDED)
3.45
32.70
0.20
36.35
0.33
4.29
0.09
4.71
0.09
10.92
1.74
12.75
7.83
70.85
0.45
79.13
0.47
5.70
0.52
6.69
1.48
53.85
1.19
56.52
0.16
2.61
0.14
2.91
LEFT
(NORMAL)
Not
Analyzed
i
















































V
REAR BRAKES
RIGHT
(SHROUDED)
4.63
18.52
0.28
23.43
0.62
1.68
0.08
2.38
2.17
3.29
0.04
5.50
- 8.22
154.50
0.36
146.64
-1.98
5.24
0.02
3.28
-0.39
3.11
0.05
2.77
9 fiO

0.23
2.83
LEFT
(NORMAL)
Not
Analyzed
I
















































1'
                                                            9-35

-------
        Table 9-25 - Weight  of Asbestos Generated During Braking
                     (Vehicle Test 3)  (yg/mile)

SCHEDULE

Burnish



A.B.
Baseline


Detroit
Traffic


10-stop
Fade


A.F.
Baseline


15-Stop
Fade

Final
Baseline


COLLECTOR

Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
Sump
Surfaces
Airborne
Total
FRONT BRAKES
RIGHT
(SHROUDED)
. 2.64
4.12
0.45
7.21
0.77
0.72
0.47
1.96
0.03
0.36
0.09
0.48
3.40
3.64
1.78
8.82
0.15
2.94
0.44
3.51
7.22
24.49
3.20
34.91
0.27
7.25
0.36
7.88
LEFT
(NORMAL)
Cumulative
Sample








































V
Not
Analyzed

REAR BRAKES
RIGHT
(SHROUDED)
2.01
9.46
0.20
11.67
0.04
1.88
0.06
1.98
0.13
0.49
0.01
0.63
2.66
2.34
0.03
5.03
0.12
0.19
0.01
0.32
0.97
0.78
0.05
1.80
3.67
15.81
0.02
19.50
LEFT
(NORMAL)
Cumulative
Sample








































v
0.10"
0.22

9-36

-------
      The data  for  the clutch emissions are given in Table 9-26.  During
vehicle test 1  and  the early stages of vehicle test 2, it was decided
to combine  the  very small  airborne samples collected as indicated in
Table 9-19.  The  treatment of the data to arrive at the asbestos emis-
sions in ug/mile  was similar to that for the brake emissions given
earlier.

9.5   ASBESTOS  EMISSIONS TRENDS

      9.5.1  New versus Burnished Materials

             The comparison of the Burnish, A.B. Baseline, and Detroit
Traffic Test overall asbestos emissions data is given in Table 9-27.
Both the right  front disc  brake and the right rear drum brake show that
the asbestos emissions generated during the Burnish schedule are higher
for the new friction materials.  Asbestos emissions decrease for slightly
used materials  during the  A.B. Baseline schedule.  The asbestos emissions
increase slightly with increased use as shown with the Detroit Traffic
test.

             The rear drum brake data showed two effects brought out by
the vehicle test  scheduling and material selections:
      • The data above indicate  that the Detroit Traffic asbestos
        emissions  are higher than for the A.B. Baseline.  This effect
        is probably due to the extent of conditioning of the lining
        prior  to each test.   The Burnish duty is slightly heavier than
        the A.B. Baseline duty and this may be responsible for the dif-
        ferences between  the A.B. Baseline and the Detroit Traffic
        results, even though both latter tests are identical in duty.

      • Vehicle  test 2 used the same linings as vehicle test 1.  The
        Burnish, A.B.  Baseline, and Detroit Traffic schedules showed
        lower  asbestos emissions than vehicle test 1.  The data demon-
        strate that asbestos emissions decrease with increased lining
        life.
             The amount of clutch airborne wear debris collected for
vehicle test 2  was  less than for vehicle test 1.  The progression through
vehicle test 3  would have  continued, except for the fact that several
severe clutch applications and clutch slippages were made to increase
the amount  of debris to simulate generation of emissions under more se-
vere conditions.  In spite of this practice, the asbestos percent of
the debris  and  the  airborne asbestos emissions content for the clutch
samples decreased with use as shown in Figure 9-3.

      9.5.2   Disc  Versus  Drum Brake Materials
             The data given in Table 9-27 also indicate the following
trends:

      • For all  moderate-duty schedules, the drum brakes produced more
        total  emissions than the disc brake.
                                                                    9-37

-------
            Table 9-26 - Summary of Clutch Asbestos Emissions
SAMPLE



AIRBORNE




SURFACES
SUMP
VEHICLE
TEST



1



2

3
	
SCHEDULE
Burnish
A.B. Baseline
Detroit Traffic
10-Stop Fade
A.F. Baseline
15-Stop Fade
Final Baseline
Burnish
Cumulative
(A.B. Baseline
To Final Baseline)
Cumulative
(Burnish to
Final Baseline)
Cumulative for all
3 Vehicle Tests
Cumulative for all
3 Vehicle Tests
WEAR DEBRIS
WEIGHT
0.0005
0.0042
0.0097
0.0001
0.0009
0.0003
0.0040
0.0004
0.0058

0.0126
1.9519
14.8472
ASBESTOS
WEIGHT
PERCENT
N/A
N/A
0.291

0.493

N/A
0.136

0.035
0.099
0.047
ASBESTOS
(Mg)


0.028

0.026


0.008

0.004
1.930
6.990
ASBESTOS
(ug/mile)


0.019

0.032
(0.023)

0.003

0.001
0.239
0.864
       Table 9-27 - Comparison of Asbestos Emissions from New and
                    Burnished Materials
Location
RIGHT
FRONT
DISC
BRAKE
RIGHT
REAR
DRUM
BRAKE

Vehicle
Test
1
2
3
Totals
1
2
3
™— — W.HH^__
Burnish
(ug/mile)
16.70
36.35
7.21
60.26
59.09
24.43
11.67
94.19
.
A,B. Baseline
(ug/mile)
2.23
4.71
1.96
8.90
9.22
2.38
1.98
13.58
Detroit
Traffic
(Mg/mile)
2.35
12.75
0.48
15.58
11.07
5.50
0.63
17.20
*~" ^^^^V^^^^M
Burnish
A.B. Baseline
7.5
7.7
3.7
Average: 6.3
6.4
10.3
5.9
Average: 7.5
Burnish
A.B.B. + D.T.
2
7.3
5.3
9.2
Average : 7.3
5.8
7.3
Average: 8.8
9-38

-------
   1.00-1
   0.8CH
in
o
Is  °-6°'
ffi
LU
u

-------
VO
                                    Table 9-28 - Asbestos Emission from Heavy-Duty Tests
Location
Right
Front
Disc
Brake
Right
Rear
Drum
Brake
Vehicle
Test
1
2
3
Totals
1
2
3
Totals
10-Stop Fade
(ug/mile)
100.60
79.13
8.82
188.55
22.58
146.64
5.03
174.25
A.F. Baseline
(ug/mile)
29.61
6.69
3.51
39.81
5.21
3.28
0.32
8.81
15-Stop Fade
(ug/mile
2040.76
56.52
34.91
2132.29
5.66
2.77
1.80
10.23
Final Baseline
(ug/mile)
28.53
2.91
7.88
39.32
5.67
2.83
19.50
28.00
10-Stop Fade
Detroit Traffic
42.8
6.2
18.3
Average: 22.4
2.0
26.7
8.0
Average: 12.2

-------
The following trends are noteworthy:

      • The right front brake  emissions were higher than the correspond-
        ing rear brake results as  only the front brake experienced the
        true fade temperatures because of the brake designed balance.
      • The 15-Stop Fade  total emissions for the front brake were higher
        than for the 10-Stop Fade  total, again because of the higher
        temperatures experienced,  as  compared to the 10-Stop Fade.
      • The A.F. Baseline and  Final Baseline total emissions were higher
        than the corresponding A.B. Baseline total given in Table 9-25
        by a factor of approximately  4.4 for the front brake.

      • The right rear drum brake  show higher emissions for the 10-Stop
        Fade than for the 15-Stop  Fade due to a shift in duty to the
        rear brakes as the  front brakes fade during their first heavy-
        duty experience.
             The above total-wheel asbestos emission trends indicate that
there is a rise in total asbestos emissions produced with high temperature
use.  This trend was only  partially reflected in a slight asbestos percent
increase indicated earlier in Tables 9-16, 9-17, and 9-18.  The greatest
portion of the asbestos emissions increase was due mainly to the largdr-
than-normal amount of wear debris produced during and after the heavy
duty and high temperatures experienced by the friction materials, as indi-
cated in Tables 9-9, 9-10, and  9-11, and considering the mileages for
each schedule.

             The following  observation was also noteworth in the compari-
son of moderate and heavy-duty  tests:
      • The ratio of asbestos  emissions for the 10-Stop Fade to Detroit
        Traffic Tests (far  right column of Table 9-27) was higher than
        the ratio of asbestos  emissions for the Burnish to A.B. Baseline
        plus Detroit Traffic test  average (far right column of Table
        9-26).  The order of decreasing asbestos emissions from brakes
        can be summarized:
             Fade (or heavy-duty stops)
                                                   I  Decreased
             Burnish                               I  Asbestos
             A.B. Baseline  + Detroit  Traffic      jf Emissions
                (moderate driving)

      9.5.4   Effects of Friction Materials
             The data for the  asbestos emissions were rearranged for
each brake as shown on Table 9-29.  This is the best way to compare the
results due to the different friction  materials.  The following trends
were noted:
                                                                   9-41

-------
    Table 9-29 - Comparison of Asbestos Emission  Generated by Different
                 Friction Materials
Duty

Moderate

Heavy
to
Abusive

Schedule
Burnish
A. B. Burnish
Detroit Traffic
Totals
10-Stop Fade
A. F. B seline
15-Stop Fade
Final Baseline
Totals
Asbestos Emissions (tag/mile)
Vehicle Test 1
Front
16.70
2.23
2.35
21.28
100.60
29.61
2040.76
28.53
2199.50
. Rear
59.09
9.22
11.07
79.38
22.58
5.21
5.66
5.67
39.12
Vehicle Test 2
Front
36.35
4.71
12.75
53.81
79.13
6.69
56.52
2.91
145.25
Rear
23.43
2.38
5.50
31.31
146.64
3.28
2.77
2.83
155.52
Vehicle Test 3
Front
7.21
1.96
0.48
8.65
8.82
3.51
34.91
7.88
55.12
Rear
11.67
1.98
0.63
13.98
5.03
0.32
1.80
19.50
26.75
                              ESTIMATED VARIATION
                              ON ESTIMATE OF INITIAL
                              ASBESTOS CONTENT.
                                 60         65

                              ASBESTOS CONTENT (WT %)
                                       70
                                                                       CO
                                                                       01
    Figure 9-4 -
Variation of Asbestos  Emissions During Moderate Duty
With Asbestos  Content  of Disc Pads
9-42

-------
     •  For the disc pads, there was an increase in asbestos emissions
        for increases in pad asbestos content:

                                Estimated
              Vehicle            Asbestos            Asbestos
               m                 n                   Emissions
               Test              Content              .   .
                             (Weight percent)        (.jag/mile)

                 3                  60                  8.65
                 1                  65                 21.28
                 2                  70                 53.81

        These data are plotted in Figure 9-4 and show an almost linear
        relationship, predicting a zero asbestos emission content when
        the pad asbestos content falls below 55 weight percent.
     •  There was no such trend for the drum brake data.
     •  Both the disc pads and the drum linings of vehicle test 3 showed
        the lowest asbestos emissions of all three tests.  Both the disc
        pads and the secondary linings contained brass chips which may
        have been responsible for the almost complete conversion of the
        asbestos in the brake emissions of the respective wheels.

     9.5.5   Airborne versus Sump versus Surfaces Samples
             The comparisons of the asbestos emissions found in the sump,
surfaces and airborne sample locations can be determined from the data
given in Table 9-30.  The data can be summarized and compared (Table 9-31):

     Front Disc Brake Trends
     •  For the moderate-duty tests, the airborne asbestos emissions
        were 6.12 percent of the total emissions.  The surface samples
        contributed 76.80 percent while the sump samples were 17.02
        percent.
     •  For the heavy-duty tests, and as a result of the severely
        burnished rubbing surfaces, the airborne asbestos emissions
        were only 0.71 percent and the sump samples 6.71 percent as
        the surfaces samples increased to 92.58 percent.

     Rear Drum Brake Trends
     •  For the moderate tests, the airborne asbestos emissions were
        2.00 percent of the total emissions.  The surfaces samples
        contributed 88.28 percent while the sump samples were 9.72
        percent.
                                                                   9-43

-------
    Table 9-30 - Comparison of Asbestos Emissions for Various  Sample
                 Locations (ug/mile)
Duty



Moderate







Heavy
or
Abusive



Vehicle
Test

1


2


3



1



2


3

Schedule
Burnish
A. B. Baseline
Detroit Traffic
Burnish
A. B. Baseline
Detroit Traffic
Burnish
A. B. Baseline
Detroit
Averages :
10-Stop Fade
A. F. Baseline
15-Stop Fade
Final Baseline
10-Stop Fade
A. F. Baseline
15-Stop Fade
.Final Baseline
10-Stop Fade
A. F. Baseline
15-Stop Fade
Final Baseline
Averages :
Front Disc Brake
Sump
6.77
0.04
0.35
3.45
0.33
0.09
2.64
0.77
0.03
1.61
57.13
3.52
78.69
1.90
7.83
0.47
1.48
0.16
3.40
0.15
7.22
0.27
13.52
Surfaces
9.42
1.04
1.91
32.70
4.29
10.92
4.12
0.72
0.36
7.28
41.77
25.12
1957.40
24.85
70.85
5.70
53.85
2.61
3.64
2.94
24.49
7.25
185.04
Airborne
0.51
1.15
0.09
0.20
0.09
1.74
0.45
0.47
0.48
0.58
1.70
0.97
4.47
1.78
0.45
0.52
1.19
0.14
1.78
0.44
3.20
0.36
1.42
Rear Drum Brake
Sump
N/A
1.01
0.39
4.63
0.62
2.17
2.01
0.04
0.13
1.38
—
0.71
—
1.61
	
—
1.30
2.66
0.12
0.97
3.67
1.58
Surfaces
58.11
7.47
10.50
18.52
1.68
3.29
9.46
1.88
0.49
12.38
22.11
4.43
5.47
4.05
154.50
5.24
3.11
1.30
2.34
0.19
0.78
15.81
18.28
Airborne
0.92
0.74
0.18
0.28
0.08
0.04
0.20
0.06
0.01
0.28
0.47
0.07
0.19
0.01
0.36
0.02
0.05
0.23
0.03
0.01
0.05
0.02
0.13
9-44

-------
   Table 9-31 - Summary Comparison of Surfaces,
            Sump, and Airborne Samples
BRAKE SYSTEM
Disc Brake
Moderate Duty
Heavy Duty

Drum Brake
Moderate Duty

Heavy Duty

Average (wt)

SUMP
(ug/mile)
1.61
(17.02)*
13.52
(6.71)

1.38
(9.72)
1.58
(7.90)
4.52
(7.33)
SURFACES
(ug/mile)
7.28
(76.86)
185.04
(92.58)

12.38
(88.28)
18.28
(91.45)
55.75
(91.68)
AIRBORNE
(ug/mile)
0.58
(6.12)
1.42
(0.71)

0.28
(2.00)
0.13
(0.65)
0.60
(0.99)
fc
 Data in parentheses  are the percents  of the total
 samples for the  condition considered.
                                                         9-45

-------
       •   For the heavy-duty tests,  and  as  a result of redistribution  of
          the sump sample, the airborne  asbestos  emissions were only
          0.65 percent and the sump  samples 7.90  percent as the surfaces
          samples increased to 91.45 percent.

 9.6    CHANGES IN LINING WEAR RATE AFTER  USE AT HIGHER TEMPERATURES

       One of the goals of the project was to ascertain the changes in
 lining wear rate and the corresponding asbestos contents after precon-
 ditioning at elevated temperatures.  The lining wear changes are given
 in Table 9-32.
       The A.B. Baseline schedule (and the other Baselines) consisted of
 a  three-day Detroit Traffic driving  test.   The Detroit Traffice schedule
 consisted of twelve days of the same road pattern.   Thus one-fourth of
 the Detroit Traffic schedule was equivalent to the  A.B.  Baseline schedule.
 The data for the front brakes showed good consistency for each of these
 schedules.  The data for the rear brakes showed wider variations.
       The A.F. Baseline and Final Baseline  schedules were run after the
 10- and 15-Stop Fade schedules followed  by  a Reburnish schedule.   The
 right  front brake indicated >550°F during the  fades and  had a wear
 factor approximately 250 percent greater than  the one-fourth Detroit
 Traffic schedule.  The left front brake  indicated only 300-370°F during
 the 10-stop fade (due to increased intervals)  and had a  wear factor
 approximately 120 percent greater than the  A.B. Baseline and the one-
 fourth Detroit Traffic schedules.

 9.7    RESULTS OF GASEOUS EMISSIONS ANALYSES

       9.7.1   Summary of Analytical  Methods  Attempted

              Analysis of the gaseous emissions was made difficult by
 the large quantities of water and carbon dioxide present in the samples.
 Calculations were made which indicated that  the flow through the rotating
 seals  was approximately 0.5 to 0.7 percent  of  the total.   Even when
 gaseous emissions collections were made  during their peak formation such
 as the fade tests, sufficient quantities of  untreated air entered through
 the rotating seals (downstream of the Drierite and  calcium oxide)  to
 present serious analytical interferences.

              Several different analytical  schemes  were  used and proved
 only partially successful.  Initially, the  entire contents of  the char-
 coal ^ gas traps were condensed in the gas handling system described in
 Section 8.5.2.  Traps cooled with acetone-dry  ice and LN2 were employed.
 The noncondensable gases proved to be essentially 100 percent  air;  no
 other  gases could be detected except for a  small amount  of C02.  When
 all this gas was pumped away and the LN2 removed, the trap was found to
 contain 100 percent C02.  In one instance,  the C02  vapor pressure built
 up so  fast that a stop-cock barrel was shot  out of  the system.  In
 attempts to trap heavier gases and reduce the  danger of  a high pressure
9-46

-------
                                Table 9—32  - Change  in Lining Wear Rate After  Operation at Increased
                                               Temperatures

SCHEDULE

A.B.
BASELINE
DETROIT
TRAFFIC
(*4)

A.F.
BASELINE
FINAL
BASELINE
Vehicle
Test
No.
1
2
3
Avg.
1
2
3
Avg.
1
2
3
Avg.
1
2
3
Avg.
Miles
328
348
368
358
357
343
356
339
347
353
326**
352
Stops
682
483
520
562
570
750
480
542
843
594
**
464
352
Pedal
Appl.
1382
1330
1370
1412
1375
1507
1432
1045
1298
1444
**
1202
1433
FRONT BRAKES
RIGHT
(SHROUDED)
Max.
Temp
(°F)*
310
320
330
360
330
300
-v-550
550
520
^625
600
560
Wear
Per Stop
(Mg)
2.73
2.38
5.40
3.50
2.53
1.80
1.67
2.00
6.95
5.12
2.50
4.86
6.28
4.07
4.87
5.07
LEFT
(NORMAL)
Max.
Temp.
(°F)
170
240
170
170
210
150
360
370
300
275
310
330
Wear
Per Stop
(Mg)
1.89
2.30
2.68
2.29
1.87
1.55
1.67
1.70
2.37
2.36
1.39
2.04
2.06
1.47
2.91
2.15
REAR BRAKES
RIGHT
(SHROUDED)
Max.
Temp.
(°F)
220
200
240
260
180
240
375
290
370
325
280
430
Wear
Per Stop
(Mg)
1.20
2.50
3.64
2.45
2.63
2.33
0.61
1.86
2.12
0.52
0.73
1.12
0.83
***
1.42
1.13
LEFT
(NORMAL)
Max.
Temp.
(°F)
170
240
180
180
240
150
340
320
320
285
260
330
Wear
Per Stop
(Mg)
1.78
2.42
1.54
1.91
2.26
1.83
1.55
1.88
4.95
1.76
1.59
2.77
1.90
1.79
1.73
1.81
VO
Before Test
Data for only 11 circuits.
Brake fluid in friction materials - no result.

-------
 build-up,  the C02 was allowed  to  evaporate into the vacuum after the
 LN2  trap was replaced with acetone-dry ice.   The final fraction proved
 to be mainly C02 and water with traces of  hydrocarbons.
              An attempt to eliminate  C02  and 1^0 was made by passing
 the  gases  from the charcoal traps  through  Drierite and calcium oxide
 traps placed between the gas handling  and  the gas collection systems.
 This proved partially successful.
              The traces of gases  obtained gave only small peaks in gas
 chromatography with the thermal conductivity  detector (T.C.D.).  This
 problem was overcome by employing  the  flame ionization detector (F.I.D.)
 for  the hydrocarbon analyses.  However, all attempts proved fruitless
 in detecting anything other than minor amounts of C^'s to C%'s.  Because
 of all of  these difficulties,  it was decided  to minimize the effort
 devoted to future gas analyses.
              In a last attempt to detect  gaseous emissions products the
 gas  collection system was connected directly  to the gas injector of the
 gas  chromatograph and the sample was analyzed simultaneously with both
 T.C.D. and F.I.D.  This method proved  successful for the fade test
 products.  Although the T.C.D. detected only  the major inorganices, the
 F.I.D. gave several peaks discussed in the following section.   This
 method indicated that the initial  tests with  T.C.D.  alone did not have
 adequate sensitivity for the organic products in the C^-Cj range where
 the  entire test was sampled.  The  major drawback of this revised method
 of direct  injection is that it is  impossible  to analyze the total
 volume of products obtained.

      9.7.2   Gaseous Emissions Detected

              Table 9-33 lists the data from  the analysis of the gaseous
 emissions from vehicle test 1 while Table  9-34 lists the data from
 vehicle tests 2 and 3.

              For vehicle test 1,  the  activated-charcoal gas traps from
 the Burnish and Detroit Traffic tests  showed  traces  of C± to C4 hydro-
 carbons in large quantities of air, carbon dioxide,  and water (Table 9-33).
 No other materials could be found.

              For the 10-Stop Fade test, the  initial gases released from
 the  traps again showed traces of Cx to C4  hydrocarbons when analyzed.
 The  traps were then connected directly to  the gas  chromatrograph (G.C.)
 as described in the previous section.  The charcoal  gas trap samples  from
 the right front brake, 10-Stop and 15-Stop Fade schedule of all vehicle
 tests were analyzed with a Porapak column.  At times,  the large amount
 of air and CC>2 gave slightly earlier than  normal elution times as compared
 to the calibration blend.  The same sample was also  run on a W-98 sili-
 cone gum rubber column.  Table 9-35 lists  the elution order of different
 compounds from the Porapak column.  The table llgts  fche compounds used
 tor calibration, those detected, and possible compounds whose  elution
 occurs between the calibration compounds.  Table 9-36 lists the elution
9-48

-------
                            Table 9-33 - Data From Analysis of  Gaseous  Emissions  (Vehicle Test  1)

Schedule
Burnish
Detroit
Traffic
10-Stop
Fade
A. F.
Baseline
15-Stop
Fade
Final
Baseline
Front Disc Brake
Charcoal
Traps
Much C02 ,
air, H20,
trace CE^
Much C02,
air, H20
trace 014
64 to C8's:
benzene,
toluene,
phenol, and
cresols
Not
sampled
Low M.W.
C4-C6
Not
sampled
Condensable
Gas Trap
Water
Water

Not
sampled
1 Peak
, MW ~Cj4
Not
sampled
Rear Drum Brake
Charcoal
Traps
Much CO 2 >
air, H20,
trace Ctfy
Trace CH4,
C3H8,
i-C4H10
C02, Air, H20
CH4, C3H8,
i-C4Hio , and
high M.W.'s*
Not
sampled
C02, Air, H20
Not
sampled
Condensable
Gas Traps
Water
Water
Water
Not
sampled
Water
Not
sampled
Clutch
Charcoal
Traps
Much C02,
air, H20
trace CIfy, C2H6,
C3H8, C4Hl0's
Much C02,
air, H20
trace CH4, C2H6
Much C02
air, H20
Not
sampled
Much C02
air, H20
trace CH4
Not
sampled
VO
                    *M.W. = Molecular Weight

-------
       Table 9-34 - Data From Analysis of Gaseous Emissions (Vehicle
                    Tests 2 and 3)

Schedule
Vehicle Test 2
Vehicle Test 3
A.B.
Baseline
Detroit
Traffic
10-Stop
Fade
15-Stop
Fade
Burnish
Detroit
Traffic
10-Stop
Fade
15-Stop
Fade
Front Disc Brake
Charcoal
Traps
C02, air
H20,
trace CE^
Benzene,
tolueme,
up to
cardanol
Some high
M.W.* peaks
Some high
M.W. peaks
C02, Air,
H20,
trace City
C02, Air,
H20,
trace City plus
high M.W. peaks
Some high
M.W. peaks
Some high
M.W. peaks
Condensable
Gas Trap
Nc
ana]


1



^
>t
.yzed


r



r
Rear Drum
Charcoal
Traps
CO 2, air
H20,
trace City
C02, air
H20,
trace C-^ to CQ
Some high
M.W. peaks

C02, air, H20
trace City
C02, H20, air
C2H6 + C2H6
+ traces C^ to
C8
Not
analyzed
I
Brake
Condensable
Gas Traps
N
ana


i



ot
lyzed


r



1
*M.W. = Molecular Weight
 9-50

-------
Table 9-35 - Elution Order From Porapak Q

Air
Carbon monoxide
Methane
Carbon dioxide
Ethane
Water
Propane
Methanol
Formaldehyde
Acetaldehyde
Butane
Ethanol
Propylene oxide
Propionaldehyde
Acetone
Isopropanol
Acetic acide
Methyl acetate
Propanol
Pentane
Isobutraldehyde
Butraldehyde
2-Butanone
Methyl-ethyl ketone
Ethyl acetate
Isobutanol
Hexane
Butanol
Benzene
C7+
Calibrant
X
X
X
X
X
X
X
X


X
X


X




X






X

X

Detected
X
X
X
X
X
X
X



X








X






X

X
X
Possible













X

X




X
X








                                                    9-51

-------
                   Table 9-36 - Elution Order From W-98


Pentane
Benzene
Toluene
m+p-Xylene
o-Xylene
Benzaldehyde
Phenol
l,2,3TM-Benzene
Indene
o-Cresol
m-Cresol
2,6DM-Phenol
l,2,3,5TM-Benzene
2,4DM-Phenol
n-Dodecane
n-Hexadecane
Calibrant


X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Detected


X
X
X
X

X


X
X





Possible

X




X


X


X




9-52

-------
order of different compounds  from the W-98 column.   The table lists the
compounds used for calibration,  those detected,  and other possible com-
pounds 'expected.

     9.7.3   Shroud Extract  Analysis

             During normal fade tests,  a dark brown cloud of high mole-
cular weight organics with a  pungent odor appeared  after the seventh
to fifteenth fade stops  for each front brake.   During the 10-Stop Fade
of vehicle test 1, a cloud was  observed  for the left front brake only
as the brake shroud prevented any such release for  the right front brake.
The inside surface of the shroud was covered with a "tarry" layer which
presented the same pungent odor after all fade tests.

             The G.C. chromatogram of the shroud extracts from the 10-
Stop and 15-Stop Fade tests of  all vehicle tests were chromatographed
on an OV-101 column.  The results indicated that the shroud extract
contained organics with  molecular weights higher than n-dodecame [mole-
cular weight 170 and boiling  point 214°C (420°F)].   Cardanol is present
in all samples.
                                                                   9-53

-------
                              SECTION 10

              ESTIMATED  EMISSIONS FOR CARS AND TRUCKS
10.1  APPROACH

      The purpose  of  this  section is to develop an estimate of total
brake  and'clutch emissions  from the U.S. population of motor vehicles
in use on the roads and  highways.   Inputs include all of the test re-
sults  described earlier  in  this report,  together with a supplementary
data base on U.S. motor  vehicle population and usage and on friction
material usage and  consumption obtained  from other sources.

      Because of the  uncertainties in all of the data available, emis-
sions  can only be considered  as a  broad  range, rather than as a single
value, with the expectation that the true average emissions for both
individual vehicles and  the motor  vehicle population in general will
be within the range of values calculated below.

10.2  SUPPLEMENTARY DATA BASE

      The data base reported in the accompanying tables was obtained
from a wide variety of trade  publications and from industry and govern-
ment contacts.  Credit is given to the sources of major contributions.
Although they vary  considerably in quality, the data are, in general,
adequate for the purpose of estimating total annual emissions, because
emissions themselves can vary so widely  from vehicle to vehicle, from
operator to operator,  and from locality  to locality.

      10.2.1   Number of Vehicles in Use
               Table  10-1  lists the total U.S. motor vehicle population
as estimated by both Department of Transportation (DOT) (National Highway
Traffic Safety and  Federal  Highway Administration)(10-1)* and by the
R. L.  Polk Company/10-2)  ^e Polk census is said to be more precise
because it eliminates  multiple registrations of the same vehicle.  Polk
considers that DOT  estimates  may be as much as 13 percent too high.  Both
Polk and DOT omit military  vehicles, but include all other motor vehicles
that are state-licensed  including  police cars, school buses and the like.
Independently, the  General  Services Administration reports that 190,000
Department of Defense  vehicles are in use world-wide.

               Table  10-2  lists the U.S. braked trailer population and
Table  10-3 lists the U.S. motor vehicles with dry clutches.
*
 Numbers in parentheses refer  to  References at end of section.
                                                                    10-1

-------
              Table 10-1 - U.  S.  Braked  Motor Vehicle Population
Private Passenger Cars
(R.L..Polk Estimate 7-1-71: 83,137,324)
D.O.T. Estimate 7-1-72:
Trucks:
(R.L. Polk Estimate 7-1-71: 18,462,287)
D.O.T. Estimate 7-1-72:
(Includes 897,456 Truck Tractors)
Light
Medium
Heavy
Buses :
Under 6000 Ibs GVW*
6 -10,000
10-14,000
14-16,000
16-19,500
19.5-26,000
26-33,000
Over 33,000

12,109
4,952
125
125
645
1,290
395
1,165

,000
,000
,000
,000
,000
,000
,000
,000

D.O.T. Estimate 7-1-72
Miscellaneous Motor Vehicles: motor cycles,
etc.

D.O.T. Estimate 7-1-72
96,397,000
20,800,000

403,000
3,787,000
Total Motor Vehicles in Use**
D.O.T. Estimate 7-1-72
121,400,000
              *Gross vehicle weight; estimates from 1970-71 sales data extended by this study,
             **This total includes approximately  1.5 million public vehicles (450,000 cars,
              920,000 trucks, and 185,000 buses), but does not include 190,000 Department
              of Defense vehicles in worldwide use.
                  Table 10-2 -  U.  S. Braked Trailer Population
Class
Recreational
Travel
Camping
Boat
Miscellaneous
(Animal, Utility, etc.)
Commercial
Utility
Trucking
Full
Semi
Number
In Use
1,800,000
1,200,000
2,500,000
1,700,000
1,000,000

278,000
1,552,000

Percent
With
Brakes
95
20
35
80
60

100
100

Number
With Brakes
1,710,000
240,000
875,000
1,360,000
600,000

278,000
1,552,000
6,615,000
10-2

-------
            Table 10-3 -  U.  S.  Motor Vehicles With Dry Clutches
Vehicle
Type
Passenger Cars
Domestic
Imported
Trucks and Buses
Light
Medium
Heavy
Number
Of Vehicles
In Use

87,100,000
9,300,000

17,100,000
2,600,000
1,600,000
Percent
Containing
Clutches With
Asbestos

15
90

75
95
100

Number
Of Dry
Clutches

13,064,000
8,370,000

12,900,000
2,470,000
1,600,000
38,404,000
Source: estimate made from industry canvas,
      Table 10-4 - Yearly Additions  to U.  S.  Braked Vehicle Population
   New Vehicles Placed in Service  (Calender Year 1972):
       Passenger Cars:

       Net U.S. Production
       Net Imports
         Total

       Trucks:

         Total (estimated)
9,312,502
1,593,605
                                           Estimate Total:
                        10,906,107



                         2,600,000

                        13,506,107
   Source:  Wall Street Journal
                                                                       10-3

-------
             The DOT estimate of 117-million total vehicles, including
20.8-million trucks, is probably sufficiently accurate for estimating
brake emissions for 1972.  It should be noted that the net growth in
vehicles each year is given approximately by the sum of U.S. cars,
trucks and other vehicles sold plus imports sold (all adjusted for ex-
ports) (Table 10-2) less annual retirement of about six- to seven-
million cars and one-million trucks.(10-3, 10-4, 10-5)  The scrappage
rate tends to rise and fall with the sales rate and may well have been
closer to eight-million cars than to seven-million for 1972.  Figures
are not yet available.

             Assuming a total retirement of nine-million vehicles, the
net growth in vehicles for 1972 was approximately 4.5 million:

                       10.9 million cars sold

                      +2.6 million trucks sold
                       13.5 million total

                      - 9.0 million scrappage
                        4.5 million net growth

             The net growth in car and truck registrations from 1961 to
1971 averaged 3.12-million vehicles per year and will probably tend to
follow the same patterns over the near future.

     10.2.2  Motor Vehicle Usage

             Table 10-5 shows the approximate total number of miles
traveled by all U.S. motor vehicles to be 1.249-trillion miles for 1972,
according to a recent DOT estimate (10-1) e  fhis total is said to be grow-
ing at a 4.5- to 5.2-percent annual rate.  To accomplish this mileage,
about 100 billion gallons of motor fuel were consumed for an overall
average of a little over 12 miles per gallon.  The detailed breakdown
of mileage by vehicle type and roadway type (Table 10-6) was adjusted for
1972 total mileage from 1970 DOT data.

             Roadway mileage and usage are further identified in Table 10-6
by type of surface and by locale, whether urban or rural.  More insight
into vehicle usage is given in Tables 10-7 and 10-8 where motor vehicle
usage is classified by the purpose of the trip and length of the trip.
All of these factors cast light, to some extent, on the degree of vehicle
brake usage and emissions.

     10.2.3  Estimates of Brake Usage and Abuse

             Brake usage varies widely from gentle to abusive.  In the
following paragraphs the term abusive braking will be defined and its
extent will be explored.
10-4

-------
Table  10-5 -  Motor  Vehicle Usage by Vehicle  Type and Roadway


Vehicle
Passenger Cars
Motorcycles and
Motorbikes
Buses :
School
Commercial
Trucks-Total
Single Unit
Trucks
Truck
Combinations
Total-all vehicles
Billions
By Road
Local
Rural
109*
- A




35

33

1.9
150
of Vehicle Miles Traveled
Type and Location*
Main Total
Rural Urban Mileage
337 534 980
10.9

6.
^

119 91 245

88 77 198

31 14 47
464 635 1,249


Mileage Per
Vehicle (1970)
9,978
3,605

13,306
7,274
32,591
11,450

9,807

41,903
10,076
        *Blanks indicate insufficient data.  Other data are adjusted for 1972 total
         analysis from 1970 D.O.T. breakdown on best-estimate basis.

       **Weighted total average
           Table 10-6  - Type  and Usage of Public Roads
Road Type
1.









2.


3.


By Classification
Interstate (42,500 authc
Rural
Urban
Primary-Highways
Rural
Urban
Secondary Highways
Rural
Urban
Municipal Streets
By Location
Rural
Urban
By (Duality
Surfaced
Non-surfaced
Grand Totals
Miles of Road
rized)
30,000
5,000
705,000
	
	
2,990,000
	
	


3,169,000
561,000

784,000
2.946,000
3,730,000
Billions of
Annual Miles of
Vehicle Travel
(1972 estimate)

117
113

222
153

275
.92
277

	
	

	
	
1,249
















             Source: World Almanac, 1973 and
                   1972 Automobile Facts and Figures;  adjusted
                                                                                10-5

-------
           Table 10-7 - Motor Vehicle Usage by Purpose of Trip
Purpose of Trip
Earning a living
(driving to work, etc.)
Family business
Educational
Social
(includes vacations)
Proportion of
Total Use
42.1%
19.6
5.0
33.3
Average
Trip Length
10.2 miles
5.5
4.7
13.1
            Table 10-8 -  Motor Vehicle  Usage by Length of Trip
Length of Trip
(one way)
Under 5 miles
5 -10
10-15
15-20
20-30
30-40
40-50
50-100
Over 100

Percentage of Trips
54.1
19.6
13.8
4.3
4.0
1.6
0.8
1.0
0.8
100.0
Proportion of
Total Use
Miles, Percent
11.1
13.8
18.7
9.1
11.8
6.6
4.3
7.6
17.0
100.0%
   Average  trip length =8.9 miles
   DOT Preliminary  Survey 1969-70
10-6

-------
            Abusive braking,  with the organic-bonded friction materials
used almost universally  on motor vehicles today, implies heating the
bulk friction material to  temperatures above about 500 to 600°F.  At
these temperatures, the  phenolic resin binders gradually pyrolyze, weaken,
and become brittle, allowing wear to increase rapidly.  Because degrada-
tion is  a time-temperature phenomenon, total brake-use history is
important.

            Overheating can be caused by one or a combination of the
following:
     Dragging brakes caused by system defect or operator error.

     Repeated use of brakes to retard the vehicle on a long downgrade.
     Repeated high-speed stops.

     Maladjustment.
     Severe vehicle overloading.
     Partial brake system  failure, overworking one or more brakes.

The degree of overheating  is further influenced by ambient air tempera-
ture, wind velocity and  relative direction,  air flow around the brake
(design) and use of engine braking to assist the foundation brakes.

            In predominantly  flat terrain and on most interstate-quality
highways with gentle grades, the need to use brakes to overcome gravity
is minimal.  Here, brake overheating is rare and usually comes from
abusive  use as in the fade tests carried out under this program.

            In very hilly or  mountainous regions, overheating can occur
quite easily as was demonstrated by a team of professional test drivers
on cross country runs in 1967.   Zechel, et.al.(10-6)} described a study
where a  group of professional  test drivers drove a total of 44,000 miles
with six 1966 U.S. passenger cars in order to perform an "Automotive
Brake Evaluation Under Customer Usage Conditions."  Results of this trip
(see Table 10-9) show that abusive temperatures were reached only in
mountainous regions (and in the hot and hilly Los Angeles traffic for
one disc brake car).  Intentionally aggressive braking behavior in
Detroit, St. Louis, New  York,  and other areas of heavy traffic failed
to produce excessively high brake temperatures.
            The proportion of mountain driving mileage on these trips
was as follows:  Eastern leg,  7.8% of the total; Western leg, 7.4%, of
which 2.4% was in Los Angeles  traffic.  Repeated runs were intentionally
made over some of these  mountain roads for increased severity of the
test. Because we have shown that total emissions tend to increase with
abusive braking, its prevalence will be explored further.
            Table 10-10 gives  the results of an attempt to estimate the
proportion of U.S. driving that takes place in predominantly hilly or
mountaninous areas where long  steep grades are common.  Basic data on
                                                                    10-7

-------
            Table 10-9  -  Results of  Cross-Country  Brake  Test  Trip




Local

Eastern Trip:
Highway and rural
N.Y. City traffic
Peters and Potts Mountain
Western Trip:
Los Angeles traffic
Other city traffic
Highway and rural
in hilly areas
Rocky Mountains
Maximum Brake Temperatures (°F)
Drum Brakes (4 cars)
Average
Peak

Temperature

250
343
471

421


300
526

Maximum



350
390
580

465
360

410
650
Disc Brakes (2 Cars)
(not used on Eastern Trip)

Car "E"



	

	

320
300

300
430

Car "F"



	

	

630
410

375
748
          Source: SAE Report  SP 338 (1967)
          *Report covers 44,180 miles of coast-to-coast driving by professional
           drivers using 6 different makes  of  passenger cars.  Test were deliberately
           aggressive to generate maximum temperatures to check brake fluid boil.
          Car  "F" ran hotter  on the front wheels by more than 300°F compared to the
           rear wheels.
                         Table  10-10  - Where Vehicles  Are Used
                                                     Estimated Total Annual Usage
                                               Predominantly
                                               Flat Terrain
                                               with
                                               Infrequent, Gentle
                                               Grades
                          Steep Hills to
                          Mountainous
                          with
                          Frequent, Long,
                          Steep Grades
           Plains States   30, with
           79 million vehicles

           Partly mountainous States-
           20, with 38 million vehicles
           Estimated Usage:
             70% flat terrain
             30% steep grades

             Totals

             Percent of all
             driving

           Type of Braking Expected
  777 billion miles


  328




1,105


 88.5%

 Normal
Minor Amount
144 billion miles
144
11.5%

Severe to abusive
brake use may be
needed.
           Source:  Estimate made for this study.
10-8

-------
miles  driven in each state  are  readily available from DOT.  The percentage
of driving that takes place in  mountainous areas, where abusive brake
use may be necessary, is  estimated to be 11.5% of all driving.  The esti-
mate is subjective, to a  large  degree, and may be high, but no better
data have been located.

            Table 10-11  lists  some additional U.S. driving characteristics
recently gathered by the  American Petroleum Institute.  Table 10-12 lists
typical numbers of brake  applications per mile as measured under this and
other  brake programs.  It is an illustrative rather than an exhaustive
study  of the subject.
            Figure 10-1  illustrates the frequency of high-g stops, as
determined at the Highway Safety Research Institute of the University of
Michigan (10-7).  This shows that 50 percent of all stops are less than
0.15 g (4.8 fps2), 99 percent are less than 0.36g (11.6 fps2) and 99.9
percent are less than 0.5g  (16  fps2).  Carpenter^lO-8) confirms one point
on the University of Michigan curve and lends  credibility  to  the  data.

    10.2.4  Asbestos in  Friction Materials
            Almost all of  the  commercial friction materials used for
braking passenger cars and  trucks today are based on the unique strength
and thermal stability of  natural asbestos (chrysotile) fibers.  This has
been true for over fifty  years.   Table 10-13 shows that the asbestos
content of friction materials averages about 60 percent.
            Table 10-14  lists  the weights of the brake lining materials
used in this program.  They are typical of the weights of friction material
used on passenger cars today and will be considered average for the cal-
culations which follow.
            Compilations of data on brake rotors and friction materials
usage  appear in Tables 10-15, and 10-16, and 10-17 respectively.  Based
on the data in Table 10-16,  the total amount of asbestos contained in all
of the automotive brake friction materials sold each year is calculated
to be  about 103 million pounds  which corresponds to M.18 million pounds
used prior to grinding.   The two most knowledgeable sourcesdO-9, 10-10)
report that 90 to 120 million pounds per year are used.  A report from
IIT Research Institute suggests that 67 million pounds are used annually
in brake linings(10-11).  ^ Bureau of Mines Report (1°-12) based on 1968
data credits only 50 million pounds of asbestos to automotive use, a
number the authors find to  be much too small.   Ignoring the two latter
values, the three estimates  of  asbestos contained in linings range from
90 to  120 million pounds.   Using the calculated value of 118 million
pounds and assuming a 15-percent grinding and drilling loss, the maximum
amount of asbestos incorporated in brake friction materials is taken to
be 103 - million pounds per  year.

            A compilation  of data on clutch friction materials usage is
given  in Table 10-17.  Based on these data, the total amount of asbestos
contained in all automotive  clutch friction materials sold each year is
calculated to be about 4.5-million pounds.
                                                                     10-9

-------
             Table 10-11  - Some U.  S.  Driving  Characteristics
City
Chicago
Houston
Los Angeles
Minneapolis-St. Paul
New York
Detroit Traffic test
(this study)
Average
Daily
Mileage
35
36
32
-
38
110
Average
Speed
22.9
25.2
24.7
26.3
25.4
17
Daily
Driving
Time
88 minutes
85 minutes
70 minutes
-
85 minutes
7.0 hours
           Source: American Petroleum Institute (except for Isst  item)
                 Table  10-12 - Brake Applications Per Mile
Source
This study
University of
Michigan
Highway Safety
Research Dept.
Zechel et al,
(SAE SP-338)
Type of Traffic
Detroit traffic
Ann Arbor and
Michigan traffic
Cross Country
Eastern trip (4 cars)
Western trip (4 cars)
No. of Pedal
Applications
Per Mile
4.4
1.43
1.43
1.9
0.98
Total
No. of
Miles
8,091
6,255
8,400
24,400
No. of
Stops
Per mile
2.6

-
Average
Decelera-
tion fps
4 to 6

-
   Source:  as noted
10-10

-------
    Table 10-13 - Asbestos Content of Automotive Friction Materials
   Vehicle and Brake Type
Average Percent Asbestos
   Content by Weight*
   Passenger Cars

     Drum Linings

     Disc Pads

   Truck Segments

   Clutch Facings

   "Average composition" for use  in  the
    calculations in this report.
         68 + 5

         60 + 5

         55 + 5

         50 ± 5


         60
*Sources Estimates made for this study.
                       10             1             0.1

                   PERCENT OF DECELERATIONS EXCEEDING g
                                                               0.01  «
      Figure 10-1 - Frequency Distribution of Braking Decelerations
                                                                    10-11

-------
     Table  10-14 - Brake Friction Material Weights for Test Vehicle
Vehicle
Test

1


2


3

Friction
Material
Description
Inner Pad
Outer Pad
Primary Lining
Secondary Lining
Inner Pad
Outer Pad
Primary Lining
Secondary Lining
Inner Pad"
Outer Pad
Primary Lining
Secondary Lining
Average Per Wheel
Average Per Axle
Average Per Car
Weight of Friction Material (gms)
Front Disc Pads
Right
95.8
117.4
-
106.4
105.0
-
115.3
152.3
-
Left
93.8
116.5
-
106.1
105.6
-
113.0
160.3
-
231.3
462.6
Rear Drum Linings
Right
-
108.1
189.6
-
104.9
181.3
-
113.2
153.5
Left
-
106.4
189.3
-
102.4
180.2
•
113.7 '
167.7
311.3
622.6
1085.2
      Table 10-15 -  Number of  Newly Surfaced Rotors Used Each Year
              Rotors  replaced

              Rotors  turned or ground

              New rotors on new
                vehicles (1972)

              Total rotors with
                new surfaces per year

              Percent of vehicles with new surfaces:

                           68,570.000
                           VW J _/ / \J j \J\J\J	     f\f\

                        4 x 123,323,000  x   ° =
 4,700,000

 9,810,000

54,060,000


68,570,000*
              *Source;  Stanford Research Institute Data.
10-12

-------
                Table 10-16 - Compilation of  Annual  Motor Vehicle  Brake  Friction
                              Material Usage
Vehicle
Passenger
Car
Light
Truck
Medium
Truck or Bus
Heavy
Truck
Miscellaneous
(Trailers, etc.)
Description
Front Disc
Pads Only
Front Drum
Linings Only
Rear Drum
Linings Only
Drum Linings
Drum Linings
Drum Linings
Drum Linings
Amount Used
Number and Unit
9,660,000 Axle Sets
24,300,000 Axle Sets
32,400,000 Axle Sets
4,730,000 Vehicle Sets
670,000 Vehicle Sets
781,000 Vehicle Sets
	
Weight
Per
Unit (Ibs)
1.0
1.8
1.3
5.0
15.0
41.0
	

Total Weight
(Ibs)
9,660,000
43,700,000
42,100,000
23,700,000
10,100,000
32,100,000
10,000,000
171,360,000
Source: Calculated from Friction Materials Standards Institute,
        D.O.T., and Stanford Research Institute Data.

-------
    Table  10-17 -  Compilation  of  Annual  Clutch  Friction Material Usage
Vehicle
Passenger Cars:
Domestic
Imports
Totals
Trucks :
Light
Medium
Heavy
Totals
New

900,000
1,350,000
2,250,000

1,500,000*
290,000*
190,000*
1,980,000
Annual Clutch Facing Use
Replacement
New



1,760,000



935,000
Rebuilt



280,000



1,170,000
Total
Units
Installed

1,710,000
2,580,000
4,290,000

3,100,000*
600,000*
385,000*
4,085,000
Weight
Per Unit
(Ibs)

0.88
0.60


1.26
1.56
2.26

Total
Clutch Weight
(Ibs)

1,500,000
1,550,000


4,000,000
950,000
680,000
8,740,000
 *Estimated for ratio each truck size with clutch (Table 10-3)

  Source:  Estimated from market studies and industry sources  for this study
                Table 10-18  - Relative Brake Relining  Frequency
                   Locale
                   Northeast

                   South

                   Large cities  (over 1 million)

                   Medium cities  (100,000-500,000)

                   Small cities  (under 25,000)

                   Rural areas

                   Average -U.S.
No.  of Wheels Relined
Per  100 Vehicles Each
Year
         74

         49

         82

         93

         54

         44

         60*
                  *Approximately equivalent to relining all four wheels
                   on 15% of all vehicles each year.
10-14

-------
               Frequency  of  brake relining is another measure of lining
use, Table 10-18(10-13).  Multiplying the relining rate of 15  percent
per year times the vehicle population of 123 million and adding, the number
of new vehicles registered last year, 13.5 million, gives 32,100,000 ve-
hicle sets as an estimate  of  annual friction materials usage.  This is
a somewhat smaller number  than that derived in Table 10-16, probably be-
cause insufficient emphasis was given to medium and heavy trucks in these
data.  One word of caution is in order at this point: the amount of fric-
tion material worn away  each  year is significantly less than that which
is installed for a variety of reasons to be discussed in the next
sub-section.

      10.2.5   Amount of  Friction Material Actually Worn

               For several reasons, the amount of brake lining (and
asbestos) worn away during a  year is significantly less than the total
amount installed on vehicles.  Brake linings are seldom completely worn
away  (due to the geometry  of  brake systems, perhaps 10 percent of the
lining is still left  on  a  brake when lining wear-through occurs).  Linings
are usually replaced  in  sets  rather than piecemeal.  As a consequence of
this  and other actions,  about 25 percent of all brake linings is discarded
at relining time.  Furthermore, millions of vehicles are retired from
service each year, many  with  brake linings that are far from worn out.
Perhaps the average retired vehicle has about 1/3 of its usable lining
remaining, or 1/3 x 90 percent + 10 percent = 40 percent of the installed
weight of the lining.
               Combining  these figures, the amount of brake friction
material worn away each  year  is calculated as follows:

                                                          Total Brake
                                                       Friction Material

Installed weight each year                             171.4 million Ibs

Less  Discarded on relining -  25%                        42.7 million Ibs

Less  discarded on vehicles retired                      11.7 million Ibs

(7 million cars x 2.38 Ib  x 40% = 6.7 +
(0.75 million light trucks x  5 Ibs x 40% = 1.5)+
(0.10 million medium  trucks x 15 Ibs x 40% = 0.6)+
(0.15 million heavy trucks'x  41 Ibs x 40% = 2.4)+
(miscellaneous =0.5)
Amount worn away, annually                             117.0 million Ibs
                                                                    10-15

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                Employing the same reasoning for  clutches,  the  amount of
clutch material worn away is calculated as follows:

                                                          Total  Clutch
                                                       Friction Material

Installed weight each year                               8.76 million Ibs
Less discarded on relining - 15%                         1.31 million Ibs

Less discarded on vehicles retired                       0.89 million Ibs
(1.5 million cars x 0.75 Ibs x 40% = 0.45)+
(0.50 million light trucks x 1.26 Ibs x 40% = 0.45)+
(0.10 million medium trucks x 1.56 Ibs x 40% = 0.06)+
(0.15 million heavy trucks x 2.26 Ibs x 40% = 0.13)

Amount worn away, annually                               6.56 million Ibs
                Summarizing, the combined total of brake and clutch fric-
tion material worn away annually is 117.0 + 6.6 = 123.6  million pounds.
Assuming that the average asbestos content is 60 weight  percent, the
amount of asbestos worn away as friction material wear debris is ^74
million pounds.

10.3   INTERPRETATION OF TEST RESULTS

       10.3.1   Factors Influencing Rate of Emissions

                Emissions measured during this program were generated by
an intentionally severe schedule, one that is used by the industry to
accelerate brake testing.  Consequently, emissions were  undoubtedly gen-
erated at a rate somewhat above average for the population as a whole.
                Emissions per mile for a given brake can vary,  for ex-
ample, with the following:

       •  Composition of the friction material

       •  Composition, metallurgical structure and hardness of  the
          cast iron rotor (drum or disc).
       •  Surface roughness of the rotor.

       •  Previous use (history) of the friction material - primarily
          thermal history, both recent and overall.

       •  Third-body contamination of the sliding interface by
          road dust, wear debris, rain water, salt and the like.
       •  Vehicle usage - miles driven:  urban, surburban, rural,
          expressway.

       •  Vehicle weight, including passengers and cargo.

       •  Vehicle speed at beginning (and end) of stop.
10-16

-------
      •  Deceleration (average or typical, as well as instantaneous).
      •  Frequency of braking due to traffic, terrain, and
         driver habits.

      •  Interface temperature, sliding speed, and unit load on
         the friction material.

      •  Roadway surface and grade.

      •  Air temperature, wind velocity, and wind direction
         relative to direction of vehicle motion.

      •  Brake design, including brake balance front to rear,
         and swept area in relation to vehicle weight and
         horsepower.

      •  Vehicle design including brake cooling  adequacy.
      •  Operator habits and behavior - riding the brake,
         gentle stops versus rapid deceleration  versus abusive
         deceleration, etc.

      •  Brake adjustment and maintenance - balance from side
         to side and front to rear.

Some  of the above factors are not independently variable, but are mentioned
for emphasis.  Tires (radial versus bias belt), engine-transmission brak-
ing,  suspension, and aerodynamic shape also influence vehicle braking to
some  extent.
               During this test program, emissions were measured under
the following sets of conditions:
      •  Seven different friction material formulations made
         by five different manufacturers.

      •  Disc versus drum brakes.
      •  New friction materials versus used friction materials.

      •  Freshly machined rotors versus polished (used) rotors.

      •  Moderate use versus abusive use under seven driving
         categories.
               Emissions were examined for asbestos content using the
best  available techniques and confirmatory tests  were conducted at two
additional laboratories (Battelle and Johns-Manville).  The program
results for asbestos emissions were slightly higher and were chosen ex-
clusively to calculate a maximum asbestos emissions estimate.
                                                                   10-17

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       10.3.2   Weighting Factors

       10.3.2.1   Distribution Weighting  Factors

       10.3.2.1.1   Location of Wear Debris

                    Disc brakes are designed  to allow air to  pass  through
 them freely.  Because of this open design they retain less wear  debris
 than drum brakes.  Consequently, the surfaces samples for the disc brake
 are essentially emitted samples.  As indicated earlier, the disc brake
 emission collector collected all disc brake wear debris.   It  was frac-
 tionated into the following samples:

       •  airborne:    these are the light particles  which remain  in
                       the air-stream as  it progress  through -the
                       collector - in this program this material was
                       collected on filters - and the particulates
                       were presumed to be representative of  disc brake
                       wear debris which may remain airborne  in  the
                       atmosphere for a period of time.

       •  surfaces:    these are the heavier agglomerates which  quickly
                       fall to the ground or nearby surfaces - in this
                       program this material was deposited on the bottom
                       and inner surfaces of the shroud and on the brake
                       parts.

       •  sump:        these are the particles of brake debris remaining
                       in the  brake on the lining surfaces, in the rivet
                       holes,  and in the caliper.

                    The drum brake emissions collector also collected
all of the drum brake wear debris.   It fractionated into the following
samples:

       •  airborne:     there are light particles which remain in the
                       air-stream as it passes through the collector  -
                       in this  program this  material was collected on
                       filters  - and the particulates were presumed
                       to be representative  of disc brake  wear debris
                       which may remain air-borne  in the atmosphere for
                       a period  of  time.

       •   surfaces:     these are the heavier agglomerates  which quickly
                       fall  to  the  ground or nearby surfaces  - in this
                       program  this  material  was  deposited on the  inner
                       surfaces  of  the  shroud and  on the brake parts.
       •   sump:         these are the particles which remain on the  brake
                       drum  and  lining  surfaces and in the rivet holes.
10-18

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      10.3.2.1.2   Comparison of Normal  versus  Shrouded  Brakes

                   The effect which  the  shrouding produced on the
quantity and distribution of  the emissions  for the right  front disc brake
and the right rear drum brake can be  estimated as  follows.

                   The data  given  earlier in Tables 9-9  and 9-10 for
vehicle tests 1  and 2  show  that  the individual sump samples of wear
debris collected after each schedule for the normal disc  brake are com-
parable in amount to those  of the  shrouded disc  brake.  The totals are
also comparable.  On the  other hand,  the data given in Table 9-11 show
that the  cumulative sump  sample,  taken at the end of vehicle test 3, is
significantly less than the total  obtained from the summation of each
individual schedule.   Further,  the  total sump sample for vehicle test 3
is comparable in value to the average value collected for each schedule
alone of  vehicle tests 2  and  3.   Consequently, the sump sample appears
to achieve and maintain an  average  value independent of the mileage.
When the  debris  is removed, the  equilibrium value appears to reestablish
itself.
                   The surfaces  samples for the open brake behaves in a
similar manner.   The surfaces samples of the open brake were smaller
(only 2.7 to 4.5 percent  of the  shrouded brake samples).   The total
surfaces  sample  for the left front  brake, taken after vehicle test 3, was
comparable to the maximum single  value (for the  Detroit traffic  test -
the longest mileage test),  when  individual values are taken after each
schedule.   Here  again, an equilibrium value appears to establish itself.

                   The best  estimate for the distribution of the disc
brake wear debris when the  brake  is new can be made by considering the
Burnish data of  Table  9-13.  After  174 miles, the distribution of emis-
sions can be estimated.

           9% returned in  sump
           2% on surfaces      -  calculated from open brake

           4% airborne         - measured at shrouded brake

           85% road dropout    - balance

                   The best  estimate for the distribution of the disc
brake wear debris for  a use brake  can be made from the data from vehicle
test 3.   After 2632 miles,  the distribution from the open disc brake is
as follows:

       1.5% retained  in  sump
       1.4% retained  on  surfaces - evaluated from open brake

       7%  airborne             - average from shrouded brake

      91%  road-dropout         - balance
As the brake is  used,  the amount retained in the brake remains constant,
but the percent  values for  retention decrease to less than one percent.
                                                                   10-19

-------
 The average for the airborne  samples  for 8100 miles is six percent.   Thus
 the distribution  for the well-used  disc brake can be estimated as follows:

        1% retained in brake

        6% airborne
        93% road drop-out
 No major  change in these relative proportions is  expected for continued
 operation beyond  the 8100 miles  of  the  test to wear-out.
                    The data  given  in Table 9-9 for vehicle test 1 show
 that  the  amounts  of sump sample  debris  collected  after each schedule  for
 the normal (unshrouded) drum  brake  are  somewhat comparable to those of
 the shrouded  drum brake.  The totals  are also somewhat comparable, al-
 though  the total  for the shrouded brake seems slightly low.   The surfaces
 samples are slightly less for the normal drum brake and the overall totals
 for the entire test show that approximately 53 percent of the surfaces
 samples remained  in the brake.   The negative numbers for the sump samples
 are real.  Since  80 percent of the  sump sample from the previous schedule
 was reintroduced  onto the brake  drum  prior  to each following schedule,
 it was  possible for the sample to redistribute in such a way that the
 sump  sample decreased to a value less than  the original amount added.
 The surfaces  sample showed a  corresponding  increase so that the total
 debris  generated  was never a  negative value for the shrouded brake.  The
 normal  drum brake could and did  occasionally show a negative value for
 total debris.

                    The rear  brake  data given in  Table 9-10 for vehicle
 test  2 was for the continued  testing  of the used  original equipment rear
 brake linings from vehicle test  1.  Thus each rear wheel started with
 the 80 percent sump debris addition (from vehicle test 1).   The total
 debris  collected  from the shrouded  brake for vehicle tests  1 and 2 were
 comparable.   The  total debris from  the  open brake was less  for vehicle
 test  2  than for vehicle test  1.  The  only explanation feasible is as
 follows.  The amount in the sump debris  of  this test is  at  an equilibrium
 level and there is no more physical room for the  material.   Thus it falls
 out of  the wheel  immediately  and less debris is distributed to the sur-
 faces in  vehicle  test 2 as compared to  vehicle test 1.

                    The best  estimate for the normal distribution of
 drum  brake wear debris when the  brake is new can  be made from the Burnish
 data  of Table 9-13.  After 174 miles, the distribution of emissions can
 be estimated  as follows:

          16% retained in sump
          29%  retained on surfaces - calculated from open brake

          1% airborne             - measured at shrouded brake
          54 road  drop-out         - balance
10-20

-------
                    The best  estimate for the distribution of drum brake
wear debris for a used brake  can be made by extending the data in
Table 9-11 for vehicle test  3.   For 2632 miles, the open drum brake
accumulated the following:
       Sump debris:     0.97  gm (9% of weight loss)
       Surface debris:  1.91  gm (17% of weight loss)
Supplementary data  from employees'  vehicles and vehicles submitted for
brake relines in local shops  indicated the following trends for friction
materials with an average  life  of 40,000 miles:
       After 5000 miles:
        Sump debris:      ^2 gm (vLO% of friction material wear)
        Surfaces debris:  ^4 gm (^18% of friction material wear)
       After 25,000  miles:
        Sump debris:      V3 gms (^5% of friction material wear)
        Surfaces debris:  M.O  gms (vL2% of friction material wear)
       After 40,000  miles:
        Sump debris:      ^4 gms (^3% of friction material wear)
        Surfaces debris:  ^12  gms (M.0% of friction material wear)
The trends are graphically illustrated in Figure 10-2.
                    Not all of  the wear debris found in a brake is from
the friction material itself.   The analysis of a few samples for iron
content indicated approximately 5-15 percent by weight  is iron oxide
which came from the  rotor wear.
                    In this program, no driving or braking took place
on dusty or salted roads.  However, the average consumer would drive
under these conditions at times  and this would slightly alter the com-
position of the retained brake  debris.   For purposes of estimation, the
average vehicle has  linings that are 50 percent worn (at the 20,000 mile
point on Figure 10-2) and the contributions to the atmosphere can be
estimated in the following manner:
       13% retained  in sump
        6% retained  on surfaces
        2% airborne
       79% road drop-out
                                                                    10-21

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    20
    16-
 3?
 Q
 <  12
 CC
 CO
 cc
 co
 III
 0
 DC
8-
     4-
       20
       16 -
     O)
CO
cc
to
Uj
Q
DC
       12 -
a j
o -
            4-
                              PERCENT SURFACES
                               DEBRIS RETAINED
                                                         WEIGHT OF
                                                       SURFACES DEBRIS
                      PERCENT SUMP
                      DEBRIS RETAINED
                                                            WEIGHT OF
                                                           SUMP DEBRIS
                        10,000
                               20,000

                               MILES
                                   30,000
                                                  40,000
                                                                        n
                                                                        01
                                                                        01
      Figure 10-2 - Variation  of  Wear Debris Retention with Mileage
                    (for Rear  Drum Brakes)
       10.3.2.1.3    Summary
                     As  a result of the above analysis,  it  is  proposed
that the test results be weighted in the following manner  for the deter-
mination of asbestos emissions distribution from a passenger  vehicle:
      Simulation

Disc Brake:

   New friction couple
   After 2632 miles
   After 8100 miles
   After 20,000 miles

Drum Brake:

   New friction couple
   After 2632 miles
   After 20,.000 miles
                    Test Schedule
                      Required
                      Burnish
                      Composite
                      Composite
                      Composite
                      Burnish
                      Composite
                      Composite
                              Airborne      Road     Vehicle
                            (Atmosphere)  Drop-Out  Retention
                                0.04
                                0.07
                                0.06
                                0.06
                                0.01
                                0.02
                                0.02
                                                0.85
                                                0.91
                                                0.93
                                                0.93
                                                0.54
                                                0.72
                                                0.79
0.11
0.03
0.01
0.01
0.35
0.26
0.19
10-22

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      10.3.2.2   Severity Weighting  Factors

      10.3.2.2.1   New Versus Burnished  Friction Materials

                   The vehicle  test  results  indicated that rerunning
the rear drum linings from vehicle  test 1 on  vehicle test 2 gave lower
asbestos emissions.  The A. B. Baseline and Detroit Traffic schedules of
vehicle test 2 showed lower asbestos  than the corresponding schedules of
vehicle test 1.  The same trends were shown for the clutch.  Consequently,
it is necessary to include a  certain  percentage (weight)  of Burnish
schedule results in the calculations  of total asbestos emissions.
                   Burnish tends to  be completed after approximately
200 miles of test driving schedules,  but  stability of surface finish may
not occur until somewhat later on private passenger cars.  Assuming that
the maximum is 400 miles and  that; the brake friction materials have a
30,000-mile average life, the fraction of driving is:


                              400  -0.013
                             30,000

This is  the severity factor  used for determining the extent  of Burnish
asbestos emissions.  During  the  next period of  driving,  the  friction
materials  are still moving toward their stabilized level for light to
moderate duty.  The test vehicle used approximately 350  miles.  Assuming
that up  to 400 miles are required, the fraction of driving is kept the
same as  for the Burnish factor above.   Thus the A. B.  Baseline factor is
also 0.013.

       10.3.2.2.2   Severe or Abusive Braking
                    The  results  presented previously show conclusively
that total emissions  increase during and immediately after severe (abu-
sive) braking  (the fade  tests).   While it is necessary to test brakes
under these  abusive conditions so that they will function in emergencies,
it is not  common  to operate  vehicles in the abusive manner that generates
high emissions.   Data reported in Section 10.2 indicate that severe braking
occurs less  than  10 percent  of the time, nationwide.
                   Most  of  the  severe braking takes place in comparatively
remote or  lightly populated  mountain areas where 11.5 percent of all
driving takes place (Table 10-10).  With experience, most of the local
drivers tend to drive in  a manner where they refrain from fading the
brakes.  Assuming that the severe braking encountered under  these condi-
tions occurs a maximum of  10 percent, the fraction for severe braking
can thus be  calculated:

               0.10  x 11.5  = 1.15 percent of all driving

                   The  amount of hot-rodding followed by severe braking,
is not known.  Nor is  the  amount of  driving known when a foot is kept on
                                                                   10-23

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the brake at all times.  A further action which  causes  emissions  caused
by severe brake friction material dragging is on the unreleased emergency
brake.  To account for all of these actions, the above  fraction of  driving
should be increased to a 2.0 percent maximum.  Thus the factor for  the
10-Stop Fade consideration is 0.020.

       10.3.2.2.3   Renewal of Friction Surfaces

                    The data given in Section 9.6 show  that the wear rate
of friction materials is increased after high-temperature operation.
Consequently, the calculations of asbestos emissions requires  the inclu-
sion of an A. F. Baseline contribution.  The test vehicle used approxi-
mately 350 miles; under less than moderate duty, approximately 600 miles
would be required.  The fraction of driving which gives the A.  F. Baseline
factor can be calulated:


                               600  =0.020
                             30,000

       10.3.2.2.4   Normal Brake Operation

                    Most braking takes place under normal or low tempera-
tures (less than 300°F).  As indicated earlier, the Detroit Traffic Test
is an accelerated vehicle test and is more severe than normal driving
throughout most of the country.  The temperatures actually encountered
would be typical of warmer climates and hilly areas such as those found
in the Los Angeles area.  In any event, the Detroit Traffic Test used in
this program gives the maximum asbestos emissions expected for normal
brake operation.

       10.3.2.3   Summary

                  As a result of the above analysis, it is proposed that
the test results be weighted in the following manner for the determination
of maximum total asbestos emissions for a passenger vehicle:

                                   Test Schedule     Weighting
               Simulation            Required         Factor

          New friction couple     Burnish             0.013
          Surfaces preparation    A. B. Baseline      0.013
          Moderate braking        Detroit Traffic     0.934*
          Severe braking          10-Stop Fade        0.020
          Renewal of friction
            surfaces              A. F. Baseline      0.020

          *Determined by difference

       10.3.3   Asbestos Emissions Per Vehicle

       10.3.3.1   Total Asbestos Emissions Estimate

                  The total asbestos emissions for the test vehicle can
10-24

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be estimated from the  test  results  given in Section 9 and the severity
weighting  factors.  The  calculation is summarized in Table 10-19.   The
asbestos emissions for the  disc brakes,  drum brakes, and clutch from
each vehicle test were averaged and used with the Burnish, A. B. Baseline,
Detroit Traffic, 10-Stop Fade,  and  A.  F. Baseline schedules.   The  cor-
responding severity factors were used  to calculate the weighted emissions.
The sum of the weighted  emissions is the total asbestos emissions  expected
from an average vehicle.

      10.3.3.2   Asbestos  Emissions and Their Fate

                 The  total asbestos emissions per vehicle as calculated
above, are not merely  deposited onto the ground or entirely emitted into
the atmosphere.  In general,  the asbestos emissions can and will probably
end up in  any of three different places:

      •   retained in  the brake and/or disposed of during servicing.
      •   deposited on the  ground

      •   floated into the  atmosphere

The calculation given  in Table  10-20 shows that the largest part of the
asbestos emissions produced is  emitted from the brakes and clutch  as
drop-out material.  The  fate  of the total emissions calculated earlier for
the test vehicle is as follows:

      Road-dropout:        23.34/28.51 x 100 = 81.9 percent
      Airborne:            1.05/28.51  x  100 = 3.7 percent
      Retained in Brake:   28.51 -  24.39/28.51 x 100 =14.4 percent

 10.4   ESTIMATED ASBESTOS EMISSIONS

       10.4.1   Passenger Vehicles

       10.4.1.1   Total Asbestos Emissions
                  The estimated total asbestos emissions per year  can be
 calculated from the  following information:

       Total asbestos emissions per vehicle:   28.51 micrograms/mile
       Number of miles per year:               9,978
       Number of passenger vehicles:           96,400,000

                  Estimated asbestos emissions in pounds per year
 = -.?8'51.?P   x ID'6 ffl x 9.978 x 103 Sii^ x ^- x 96.4 x 106 vehicles
  mile-vehicle        yg                yr     454 gm

 = 60,400 pounds per year.

       10.4.1.2   Distribution of Asbestos Emissions
                  The distribution of the total asbestos emissions cal-
 culated for the test vehicle can be determined by applying the percent
 distributions  given in Section 10.3.3.2.  The fate of the 60,400 pounds
                                                                  10-25

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M
Table 10-19 - Total Asbestos Emissions Calculated From the Test
              Vehicle (Average for the Three Vehicle Tests)
Schedule

Burnish


A. B. Baseline


Detroit Traffic


10-Stop Fade


A. F. Baseline

Friction
Couple
Disc Brake
Drum Brake
Clutch
Disc Brake
Drum Brake
Clutch
Disc Brake
Drum Brake
Clutch
Disc Brake
Drum Brake
Clutch
Disc Brake
Drum Brake
Clutch
Asbestos Emissions (ug/mile)
Vehicle Test
1
16.70
59.09
—
2.23
9.22
—
2.35
11.07
—
100.60
22.58
—
29 . 61
5.21
—
2
36.35
24.43
—
4.71
2.38
—
12.75
5.50
—
79.13
146.14
—
6.69
3.28
—
3
7.21
11.67
—
1.96
1.98
—
0.48
0.63
—
8.82
5.03
—
3.51
0.32
—
Average
20.09
31.39
1.11
2.97
4.52
1.11
5.19
5.73
1.11
62.80
58.15
1.11
13.27
2.94
1.11
Per
Axle
40.18
62.78
—
5.94
9.04
—
10.38
11.46
—
125.60
116.30
—
26.54
5.88
—

Severity
Weighting
Factors

0.013


0.013


0.934


0.020


0.020

Total
Weighted
Emissions
(yg/mile)
0.52
0.82
0.01
0.07
0.12
0.01
9.70
10.70
1.03
2.51
2.33
0.02
0.53
0.12
0.02
28.51

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                               Table 10-20 - Distribution-Weighted Asbestos Emissions From the
                                             Test Vehicle

Schedule
Burnish
A.B.
Baseline
Detroit
Traffic
10-Stop
Fade
A.F.
Baseline
Friction
Couple
Disc Brake
Drum Brake
Clutch
Disc Brake
Drum Brake
Clutch
Disc Brake
Drum Brake
Clutch
Disc Brake
Drum Brake
Clutch
Disc Brake
Drum Brake
Clutch
Asbestos Emissions (pg/mile)
Vehicle Test
1
16.70
59.09
2.23
9.22
2.35
11.07
100.60
22.58
29.61
5.21
2
36.35
24.43
4.71
2.38
12.75
5.50
79.13
146.14
6.69
3.28
3
7.21
11.67
1.96
1.98
0.48
0.63"
8.82
5.03
3.51
0.32
Average
20.09
31.39
1.11
2.97
4.52
1.11
5.19
5.73
1.11
62.80
58.15
1.11
13.27
2.94
1.11
Per
Axle
40.18
62.78
5.94
9.04
10.38
11.46
125.60
116.30
26.54
5.88
Dist. Weighting
Factors
Dr op-Out
0.85
0.54
0.10
0.85
0.54
0.10
0.93
0.79
0.10
0.93
0.79
0.10
0.93
0.79
0.10
Airborne
0.04
0.01
0.01
0.04
0.01
0.01
0.06
0.02
0.01
0.06
0.02
0.01
0.06
0.02
0.01

Severity
Weighting
Factors
0.013
0.013
0.934
0.020
0.020
Total
Weighted Emissions
(pg/mile)
Drop-Out
0.44
0.44
0.00
0.06
0.07
0.00
9.02
8.45
0.10
2.33
1.84
0.00
0.49
0.10
0.00
23.34
Airborne
0.02
0.01
0.00
0.00
0.00
0.00
0.58
0.21
0.01
0.15
0.04
0.00
0.03
0.00
0.00
1.05
o
NJ

-------
calculated for the test vehicle is as follows:

                    Road-dropout:     49,470 pounds
                    Airborne:          2,230 pounds
                    Brake retention:   8,700 pounds

       10.4.2   Trucks and Buses

       10.4.2.1   Estimated Severity Factors

                  Truck brakes usually tend to operate at higher tempera-
tures than passenger cars.  Thus a greater proportion of high-temperature
use in severity weighting can be obtained by using a larger fraction of
the 10-Stop Fade asbestos emissions.  For trucks and buses, the test re-
sults are arbitrarily weighted as follows:

           Simulation          Test Schedule     Weighting Factor

       Light Truck:

          New materials       Burnish                 0.013
          Moderate braking    A. B. Baseline          0.013
          Moderate braking    Detroit Traffic         0.874
          Abusive braking     10-Stop Fade            0.050
          Surface renewal     A. F. Baseline          0.050
       Medium Truck and Bus:

          New materials       Burnish                 0.013
          Moderate braking    A. B. Baseline          0.013
          Moderate braking    Detroit Traffic         0.774
          Abusive braking     10-Stop Fade            0.100
          Surface renewal     A. F. Baseline          0.100
       Heavy Truck:

          New materials       Burnish                 0.013
          Moderate braking    A. B. Baseline          0.013
          Moderate braking    Detroit Traffic         0.674
          Abusive braking     10-Stop Fade            0.150
          Surface renewal     A. F. Baseline          0.150

       10.4.2.2   Estimated Emissions Factors

                  In addition to the severity factors, it is necessary
to estimate the total average asbestos emissions for a light truck, a
medium truck (or bus), and a heavy truck.  The value for the test car
was 28.51 micrograms/mile.  Assuming that light trucks have a result
proportional to the ratio of the friction materials weights, the asbestos
emissions for light trucks are larger than the test car by the following
factors:

                         Front drum brake:   2.0
                         Rear drum brake:    3.0
                         Clutch:             2.0
 10-28

-------
A slightly larger factor  is  selected  for the clutch as  it  is  used more
often in trucks than in passenger  cars.

                 Following  the  same  line of reasoning,  the asbestos
emissions for medium trucks  and  buses are larger than the  test  car by  the
following factors:
                         Front drum brake:   3.0
                         Rear drum brake:   10.0
                         Clutch:              4.0

The factors for a heavy truck are  as  follows:
                         Front drum brake:   5.0
                         Rear drum brake:   30.0
                         Clutch:              6.0

       10.4.2.3   Calculations of  Total Asbestos Emissions
                 for Trucks and Buses
                 The estimates  for the total average asbestos  emissions
per vehicle are shown in  Tables  10-21, 10-22, and 10-23, for  a  light  truck,
a medium truck or bus, and a heavy truck, respectively.
      Table 10-21 - Estimate for Total Asbestos Emissions Expected
                    for a Light Truck
Schedule

Burnish


A. B. Baseline


Detroit Traffic


10-Stop Fade

A. F. Baseline



Friction
Couple
Front Drum Brake
Rear Drum Brake
Clutch
Front Drum Brake
Rear Drum Brake
Clutch
Front Drum Brake
Rear Drum Brake
Clutch
Front Drum Brake
Rear Drum Brake
Clutch
Front Drum Brake
Rear Drum Brake
Clutch

Asbestos Emissions
Estimate Per Axle (ug/mile)
62.78 x 2.0'
62.78 x 3.0
1.11 x 2.0
9.04 x 2.0
9.04 x 3.0
1.11 x 2.0
11.46 x 2.0
11.46 x 3.0
1.11 x 2.0
116.30 x 2.0
116.30 x 3.0
1.11 x 2.0
5.88 x 2.0
5.88 x 3.0
1.11 x 2.0

Asbestos
Emissions
(ug/mile)
125.56
188.34
2.22
18.08
27.12
2.22
22.92
34.38
2.22
232.60
348.90
2.22
11.76
17.64
2.22

Severity
Weighting
Factors

0.013


0.013


0.874


0.050


0.050

Total
Weighted
Emissions
(pg/mile)
1.63
2.45
0.03
0.24
0.35
0.03
20.03
30.05
1.94
11.63
17.44
0.11
0.59
0.88
0.11
87.51
                                                                   10-29

-------
      Table 10-22 - Estimate of Total Asbestos Emissions Expected
                    for a Medium Truck
Schedule

Burnish


A. B. Baseline


Detroit Traffic


10-Stop Fade


A. F. Baseline

Friction
Couple
Front Drum Brake
Rear Drum Brake
Clutch
Front Drum Brake
Rear Drum Brake
Clutch
Front Drum Brake
Rear Drum Brake
Clutch
Front Drum Brake
Rear Drum Brake
Clutch
Front Drum Brake
Rear Drum Brake
Clutch
Asbestos Emissions
Estimate Per Axle (ug/mile)
62.78 x 3.0
62.78 x 10.0
1.11 x 4.0
9.04 x 3.0
9.04 x 10.0
1.11 x 4.0
11.46 x 3.0
11.46 x 10.0
1.11 x 4.0
116.30 x 3.0
116.30 x 10.0
1.11 x 4.0
5.88 x 3.0
5.88 x 10.0
1.11 x 4.0
Asbestos
Emissions
(ug/mile)
188.34
627.80
4.44
27.12
90.40
4.44
34.38
114.60
4.44
348.90
1163.00
4.4.4
17.64
. 58.80
4.44

Severity
Weighting
Factors

0.013


0.013


0.774


0.100


0.100

Total
Weighted
Emissions
(Ug/mile)
2.45
8.16
0.06
0.35
1.18
0.06
26.61
88.70
3.44
34.89
116.30
0.44
1.76
5.88
0.44
290.72
      Table 10-23 - Estimate  of  Total Asbestos Emissions Expected
                    for a Heavy  Truck
Schedule

Burnish


A. B. Baseline


Detroit Traffic


10-Stop Fade


A. F. Baseline

Friction
Couple
Front Drum Brake
Rear Drum Brake
Clutch
Front Drum Brake
Rear Drum Brake
, Clutch
Front Drum Brake
Rear Drum Brake
Clutch
Front Drum Brake
Rear Drum Brake
Clutch
Front Drum Brake
Rear Drum Brake
Clutch
Asbestos Emissions
Estimate Per Axle (ug/mile)
62.78 x 5.0
62.78 x 30.0
1.11 x 6.0
9.04 x 5.0
9.04 x 30.0
1.11 x 6.0
11.46 x 5.0
11.46 x 30.0
1.11 x 6.0
116.30 x 5.0
116.30 x 30.0
1.11 x 6.0
5.88 x 5.0
5.88 x 30.0
1.11 x 6.0

Asbestos
Emissions
(ug/mile)
313.90
1883.40
6.66
45.20
271.20
6.66
57.30
343.80
6.66
581.50
3489.00
6.66
29.40
176.40
6.66

Severity
Weighting
Factors

0.013


0.013


0.674


0.150


0.150

Total
Weighted
Emissions
(ug/mile)
4.08
24.48
0.09
0.59
3.52
0.09
38.62
231.72
4.49
87.22
523.35
1.00
4.41
26.46
1.00
951.12
10-30

-------
     Table 10-24 -  Distribution-Weighted Asbestos Emissions  From
                     A Light Truck
Schedule
Burnish
A.B. Baseline
Detroit
Traffic
10-Stop Fade
A.F. Baseline
Friction
Couple
Front Drum Brake
Rear Drum Brake
Clutch
Front Drum Brake
hear Drum Brake
Clutch
Front Drum Brake
Rear Drum Brake
Clutch
Front Drum Brake
Rear Drum Brake
Clutch
Front Drum Brake
Rear Drum Brake
Clutch

Severity
Weighted
Emissions
(mg/mile)
1.63
2.45
0.03
0.24
0.35
0.03
20.03
30.05
1.94
11.63
17.44
0.11
0.59
0.88
0.11
87.51
Distribution Weighting Factors
Drop-
out
0.89
0.89
0.10
0.90
0.90
0.10
0.90
0.90
0.10
0.90
0.90
0.11
0.90
0.90
0.10
Airborne
0.02
0.02
0.02
0.03
0.03
0.02
0.03
0.03
0.02
0.03
0.03
0.02
0.03
0.03
0.02
Retention
0.09
0.09
0.88
0.07
0.07
0.88
0.07
0.07
0.88
0.07
0.07
0.88
0.07
0.07
0.88

Weighted Emissions (mg/mile)
Drop-
out
1.45
2.18
0.00
0.22
0.32
0.00
18.03
27.05
0.19
10.47
15.70
0.01
0.53
0.79
0.01
76.95
Airborne
0.03
0.05
0.00
0.01
0.01
0.00
0.60
0.90
0.04
0.35
0.52
0.00
0.02
0.03
0.00
2.56
Retention
0.15
0.22
0.03
0.02
0.02
0.03
1.40
2.10
1.71
0.81
1.22
0.10
0.04
0.06
0.10
8.01
Table 10-25 - Summary of All  Brake and Clutch Emission  (Ibs per  year)
Vehicle
Passenger Cars
Light Trucks
Medium Trucks
and Buses
Heavy Trucks
Miscellaneous*

Number
of Vehicles
96,400,000
17,100,000
2,600,000
1,200,000
6,615,000
Totals
Total
Asbestos
Emissions
60,400
32,300
16,300
32,900
16,300*
158,200
Percent of Total
Distribution
Dr op-Out
49,470
28,420
14,330
28,920
14,330
135,470
(85.6)
Airborne
2,230
940
470
950
470
5,060
(3.2)
Brake
Retention
8,700
2,940
1,500
3,030
1,500
17,670
(11.2)
          Estimated equal to medium trucks as weights of friction material
          used for both categories, are almost equal (Table 12).  Includes
          motorcycles, trailers, etc.
                                                                           10-31

-------
                  The estimated total asbestos emissions per year for
light trucks can be calculated from the following information:

          Total asbestos emissions per vehicle:  87.51 yg/mile
          Number of miles per year:              9,807
          Number of trucks:                      17,100,000

                  Estimated asbestos emissions in pounds per year
= 87.51      x ID'6    x 9.807 x 103       x         x 17.1 x 106 vehicles
= 32,300 pounds per year

                  The estimated total asbestos emissions per year for
medium trucks and buses can be calculated from the following information:

          Total asbestos emissions per vehicle:  290.72 yg/mile
          Number of miles per year:              9,807
          Number of trucks:                      2,600,000

                  Estimated asbestos emissions in pounds per year
= 290.72 -Bf- x 10~6 SSL x 9.807 x 103 ^^. x  1 lb   x 2.60 x 106 vehicles
         mile        yg                yr     454 gms

= 16,300 pounds per year

                  The estimated total asbestos emissions per year for
heavy trucks can be calculated from the following information:

          Total asbestos emissions per mile:  951,12 yg/mile
          Number of miles per year:           9,807
          Number of trucks:                   1,600,000

                  Estimated asbestos emissions in pounds per year
= 951.12 ^f- x 10~6 ££ x 9.8o7 x 103 SilfJL x  1 ">   x 1>60 x 106 vehicles
         mile        yg                yr     454 gms

= 32,900 pounds per year

       10 . 4 . 2 . 4   Total Truck Asbestos Emissions

                  The estimated value for the total asbestos emissions
from trucks and buses is as follows:

                Light trucks               32,300 pounds
                Medium trucks and buses    16,300 pounds
                Heavy trucks               32.900 pounds
                                           81,500 pounds
 10-32

-------
      10.4.2.5   Distribution  of Truck Asbestos  Emissions

      10.4.2.5.1   Estimated Distribution Weighting Factors

                   The  distribution weighting factors for passenger car
brakes are discussed in  Section 10.3.2.1.   Trucks contain drum brakes
which are designed to be more open  than passenger car drum brakes.   In
many instances, no splash  shields are used or they are very open.   More-
over, trucks run with hard tires and stiff suspensions; these lead  to a
hard ride and more shaking at the wheels.   Consequently, the retention
of wear  debris in truck  drum brakes is estimated  to be approximately 25
percent  of that for passenger vehicle drum brakes.

                   From the data given in Section 10.3.2.1.3, it is
possible to estimate the following  distribution weighting factors for
truck drum brakes:

                           Test                   Road      Vehicle
        Simulation         Schedule     Airborne   Drop-Out   Retention

    New  friction couple    Burnish        0.02       0.89       0.09
    After 2632 miles       Composite     0.03       0.90       0.07

The airborne figure was  adjusted upward.  The openness of the disc  brake
gives rise to a higher airborne fraction than for a closed drum brake.
The value estimated for  the truck drum brake takes this into account.

      10.4.2.5.2   Truck  Asbestos  Emissions and  Their Fate
                   The  total asbestos emissions  calculated for the
light truck, medium truck  and bus,  or heavy truck will be distributed
into three places:
      o retained in the  brake and/or disposed of during service

      o deposited on the ground
      o floated into the atmosphere
The typical calculations for the light trucks are given in Table 10-24 and
can be summarized:
          Road Drop-out:    76.95/87.51 x 100 =  87.9 percent
          Airborne:         2.56/87.51 x 100  =  2.9 percent
          Brake Retention: 8.01/87.51 x 100  =  9.2 percent

      10.4.3   Estimated  Asbestos  Emissions
               The summary of  the  total asbestos emissions estimates and
their distribution is given in  Table 10-25.
                                                                   10-33

-------
   Table 10-26 - Calculation of Weighted Average Unconverted Asbestos
                Percent for Sump Sample
Schedule
Burnish

A.B.
Baseline

Detroit
Traffic

10-Stop
Fade

A.F.
Baseline


Vehicle
Test
1
2
3
Average
1
2
3
Average
1
2
3
Average
1
2
3
Average
1
2
3
Average

Front
Brake
0.813
0.402
0.218
0.478
1.650
0.236
0.106
0.664
0.247
0.304
0.018
0.190
0.463
0.244
0.045
0.251
0.656
0.443
0.158
0.419

Rear
Brake
0.484
0.063
0.274
0.179
0.268
0.063
0.170
0.129
0.240
0.046
0.138
0.280
0.199
0.102
0.194
0.419
0.138
0.034
0.197

Overall
Average
0.376

0.417

0.164

0.223

0.308


Weighting
Factor
0.013

0.013

0.824

0.075

0.075


Weighted
Percent
0.005

0.005

0.135

0.017

0.023

0.185
   Table 10-27 - Calculation of Weighted Average Asbestos Percent for
                Surfaces Sample
Schedule
Burnish

A.B.
Baseline

Detroit
Traffic

10-Stop
Fade

A.F.
Baseline


Vehicle
Test
1
2
3
Average
1
2
3
Average
1
2
3
Average
1
2
3
Average
1
2
3
Average

Front
Brake
0.398
0.968
0.101
0.489
0.472
0.311
0.024
0.269
0.137
0.548
0.013
0.233
0.162
0.261
0.041
0.155
0.507
0.173
0.073
0.251

Rear
Brake
0.865
1.416
0.046
0.776
0.415
0.098
0.056
0.190
0.373
0.113
0.057
0.181
0.071
0.619
0.055
0.248
0.242
0.237
0.022
0.167

Overall
Average
0.633

0.230

0.207

0.202

0.209


Weighting
Factor
0.013

0.013

0.824

0.075

0.075


Weighted
Percent
0.008

0.003

0.171

0.015

0.016

0.213
10-34

-------
      10.4.4   Alternate Estimate  for  Total Asbestos  Emissions

               An alternate method to  calculate an estimate  for total
asbestos emissions is proposed.

               Tables 10-26,  10-27,  and 10-28 list the data  and the
calculations required to produce  a  weighted average asbestos  percent  for
the sump, surfaces, and airborne  samples using the  weighted portions  of
the Baseline, A. B. Baseline,  Detroit Traffic, 10-Stop Fade,  and A. F.
Baseline schedules.

               The data given in Table 10-16 indicated that  the percent-
ages of annual consumption of  friction  materials is as follows:
                   Passenger  Car Brakes:  56 percent
                   Truck Brakes:           44 percent

The data given in Section 10.3.2.1.3 and Section 10.4.2.5.1 show that the
average distributions for most of the brake mileages can be summarized as
follows:
                                             Road       Vehicle
             Brake             Airborne    Drop-Out    Retention

      Passenger Car Brakes       0.03        0.77        0.20
      Truck Brakes               0.03        0.90        0.07
The calculation for the weighted  average asbestos found in all brakes is
given in Table 10-29.
               The average wear  debris recovery for each vehicle can
also be calculated from the data  given  in Table 9-14:

                                 Fronts   . Rears

                      Test 1     51.2*    67.8*
                           2     60.8      81.6
                           3     60.2      81.3
               *Low because of incomplete, difficult  recoveries
                of Fade samples.

The drum rear samples are known to  contain approximately 10 weight percent
material such as iron oxide from  drum wear.  Thus an average  recovery of
approximately 65 percent, based on  the  debris from  the friction  materials
for vehicle tests 2 and 3, is  used  in the calculation.  Therefore, the
asbestos percent based on the  friction  material worn in the test vehicle
is calculated as follows:

                         0.206 x 0.65  = 0.134
                                                                    10-35

-------
   Table 10-28 - Calculation of weighted.average.asbestos  Percent for
                 Airborne Samples
Schedule
Burnish

A.B.
Baseline

Detroit
Traffic

10-Stop
Fade

A.F.
Baseline


Vehicle
Test
1
2
3
Average
1
2
3
Average
1
2
3
Average
1
2
3
Average
1
2
3
Average

Front
Brake
0.144
0.186
0.099
0.143
0.290
0.211
0.125
0.209
0.052
0.234
0.025
0.104
0.154
0.107
0.055
0.105
0.134
0.165
0.047
0.115

Rear
Brake
0.349
0.087
0.060
0.165
0.493
0.344
0.044
0.294
0.092
0.115
0.037
0.081
0.132
0.194
0.014
0.113
0.079
0.180
0.003
0.087

Overall
Average
0.154

0.251

0.093

0.109

0.101


Weighting
Factor
0.013

0.013

0.824

0.075

0.075


Weighted
Percent
0.002

0.003

0.077

0.008

0.008

0.098
     Table 10-29 - Data and Calculation of.Weighted.Asbestos Percent
                   for All Vehicles
Friction
Materials
Passenger
Car
Truck
Fraction
of Friction
Material
0.56
0.44
Fraction
of Debris
Airborne
Drop-Out
Retention
Airborne
Drop-Out
Retention

0.03
0.77
0.20
0.03
0.40
0.07

Weight
Percent
Asbestos
0.098
0.213
0.185
0.098
0.213
0.185

Weighted
Asbestos
Percent
0.002
0.092
0.021
0.001
0.084
0.006
0.206
10-36

-------
The total weight of  friction material worn away annually in brakes is
117 million pounds.  The  total asbestos estimate from brakes can now be
calculated:

                117,000,000 x 0.00134 = 157,000 pounds

The total weight of  friction material worn away annually in clutches is
6.6 million pounds.  The  total asbestos estimate from clutches (assuming
a retention of ^75 percent)  can be calculated as follows:

                6,600,000 x 0.00047 x 0.25 = 800 pounds

Thus the total is approximately 157,800 pounds, which agrees with the
figure reported in Section 10.4.3 above.

10.5   SUMMARY OF ASBESTOS EMISSIONS

       The results indicate  that more than 99.7 percent of the asbestos
used in friction material is converted to a non-fibril form.  The total
asbestos emissions for  all vehicles in the United States is estimated
to be 158,000 pounds annually.   Of this total, a small part was found
to remain airborne.  The  contribution to the atmosphere is estimated
to be 5060 pounds, or 3.2 percent of the total asbestos emissions.
                                                                     10-37

-------
10,6   REFERENCES
       (10-1)   National Highway Traffic Safety Administration and Federal
                Highway Administration preliminary estimates, private com-
                munication, January 18, 1973.

       (10-2)   R. L. Polk & Co., private communication, January  12, 1973.

       (10-3)   "Truck Sales Jumped 24 Percent in 1972 to 2.6 Million
                Units," Wall Street Journal, January 8, 1973.

       (10-4)   "1972 Automobile Facts and Figures," Motor Vehicle
                Manufacturers Association, 1973.

       (10-5)   "Motor Truck Facts," Motor Vehicle Manufacturers
                Associaation, 1973.

       (10-6)   W. J. Zechel, et. al., "Automotive Brake Evaluation Under
                Customer Usage Conditions," SAE Special Publication SP-338,
                Society of Automotive Engineers, April 1968.

       (10-7)   R. G. Mortimer (University of Michigan), "Hard Braking
                is More Common Than You Might Think," Automotive
                Engineering, August 1971, page 32.

       (10-8)   N. Carpenter and E. G. Goddard, "The Measurement of
                Braking Performance for Compulsory Motor Vehicle Inspec-
                tion," Journal, Institute of Motor Industry, Vol. 4,
                No. 10, 1955.

       (10-9)   Private Communication, January 1973.

       (10-10)  Private Communication, January 1973.

       (10-11)  C. F. Harwood (IITRI), "Asbestos Air Pollution Resulting
                From the Wear of Braking Linings," Illinois Institute of
                Technology Research Institute, April 1972.

       (10-12)  T.(C. May and R.  W. Lewis,  "Asbestos,"  A Chapter from
                "Mineral Facts and Problems," U.S. Bureau of Mines
                Bulletin 650, 1970 edition.

       (10-13)  Private Communication, January 1973.
10-38

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                               SECTION 11

                                SUMMARY


      The  specific  objectives of this program were stated earlier.  The
end objective was the  documentation of asbestos emissions from brakes
and clutches and the assessment of their overall contributions to the
atmosphere.  These  objectives were met by means of the program as planned
and completed.

      For  the results  to  be representative of average consumer-type vehicle
usage, a vehicle intermediate between compacts and luxury vehicles was
selected.  The vehicle was  equipped with front disc brakes, rear drum
brakes, and a dry clutch.   All friction material used contained asbestos.
Three  vehicle tests were  run.  The first vehicle test was run with the
original-equipment  friction materials.  The second vehicle test simulated
a partial  reline -  fronts only relined - while the rears were repeated to
give a replicate test, and  an indication of emissions trends for friction
materials  with continued  use.  The third vehicle test simulated a complete
brake  reline, and included  turned discs and drums.  The friction materials
selected for the program  were representative of those supplied by the
industry - five different manufacturers produced the original equipment
and aftermarket disc pads and drum linings, which were selected in part
because of their high-volume usage.

      The  collection of particulate and gaseous emissions from any vehicle
friction couple has never,  to the authors' knowledge, been reported in the
literature.  To define the  extent of these emissions, a collection system
was devised which combined  the functions of separation and storage.  Unique
emissions  collectors for  both disc and drum brakes, and for a clutch, were
conceived, designed, and  built as the main embodiment of this instrumenta-
tion.   The collectors  separated the wear debris into three different frac-
tions: a  sump sample  which included the wear debris on the lining surfaces,
in the rivet holes, and on  the brake drum; a surfaces sample which in-
cluded the wear debris on the brake and collector shroud surfaces; and
an airborne sample  collected on membrane filters.
      The  front disc brake  emission collector was tested on an inertia
dynamometer to check out  its operation.  The most critical part of the
collector  operation was the rotating seal.  The final design selected
was made from graphite-filled Teflon which rotated against a hardened
steel  ring.  Thermal response tests were made, the results indicating
that for normal operation the shrouded disc brake would operate at a
slightly higher temperature than the normal brake configuration.  A
method was devised  to  determine the leak rate of the collector.  The
rotating seal was largely responsible for the residual leak; the leak
rate was reduced significantly by use of a very small amount of high-
temperature grease.  The  rotating seal underwent durability testing and
                                                                    11-1

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survived seven hours at 50 mph.  A second  series  of  dynamometer tests
gave reproducible emissions and temperatures.   Finally,  a test was made
in which the collector, and especially the rotating  seal,  were shown to
be relatively leak-tight to external liquid and particulate contaminants.

      The vehicle was equipped with standard brake test  instrumentation.
A front disc brake collector and a rear drum brake collector were  in-
stalled on the right side of the vehicle.   The  clutch was  sealed by
closing the few holes in its casing.  The  left  wheel brakes were left
in their normal configuration and were used to  monitor the operation of
the shrouded brakes.  Wear debris was taken from  the left  brakes as well
as from those on the right.  The amounts of debris formed  and their com-
positions were used to demonstrate that the brake shrouding did not
significantly affect the operation of the  brakes  on  the  right side.

      Although there are many brake and friction  material  tests suitable
for measuring a specific condition or combination of conditions, no one
test adequately matches driving conditions  which  would be  representative
of all vehicles.  Consequently, it became  necessary  to devise a rational
and meaningful vehicle test.  Seven schedules were chosen,  and each was
followed by a measurements procedure (take  emissions samples,  measure
wear, inspect the systems, and replace worn parts).  The first three
schedules - Burnish, After Burnish (A.B.)  Baseline,  and Detroit Traffic -
constituted low to moderate temperature testing.  The final four sched-
ules - 10-Stop Fade, After Fade (A.F.) Baseline,  15-Stop Fade,  and  Final
Baseline - constituted high temperature and abusive  testing.
      A detailed step-by-step procedure was  prepared for the removal of
brake emissions from the collectors.  The  amounts of debris collected
at the various locations were used later to  calculate the mass balances.
A detailed step-by-step procedure was also  prepared  for  the sampling,
handling, and analysis of the asbestos emissions.
      The analysis of brake wear debris indicated the presence of  20-30
weight percent polymeric and carbonaceous material,  which  in turn pro-
duced a fluffy appearance when the material was examined in the scanning
electron microscope.  The organic portion was therefore  removed by  low
temperature ashing.  Two representative samplings were used:   the  first
in sample selection for low temperature ashing; and  the second in  sample
selection for distribution on a filter membrane for  subsequent  analysis.

      The only suitable method of analysis  for  asbestos was microscopy.
At the beginning of the program, one optical and  three transmission
electron microscopy methods had been developed by others.   Two of  the
electron microscope methods were not suitable because they  changed  the
fiber size distribution of the asbestos.   Initial experiments  indicated
that the asbestos in wear debris varied in  size from 0.1 micron in  diame-
ter up to 2.0 microns in diameter by 50 microns in length.   To preserve
the particle size distribution, a combination of  optical microscopy and
transmission electron microscopy was selected.  Optical microscopy  with
phase contrast optics at 400 diameters was  used to detect  fibers with
11-2

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diameters of  0.5 micron and above.  Transmission electron microscopy at
22,000  diameters was  used to detect fibers with diameters of 0.5 micron
and below.

     The projected fiber diameter and length were used to determine the
fiber volume.   The volumes were summed, converted to weight, and normal-
ized for the  entire sample weighed onto the filter.  A computer program
was subsequently developed to minimize computational time and to elimi-
nate errors in  the processing of these calculations.

     The possible sources of error associated with sample processing
and analysis  were minimized through the use of statistical methods.  The
largest effect  found  on the asbestos analysis was the occasional occur-
rence of a large fiber.   The extent of error increased as the percent
asbestos in the sample decreased.   The data showed that the maximum
deviation for results with asbestos contents above 0.10 percent averaged
12-15 percent and  had  a maximum at approximately 20 percent.  The maxi-
mum deviation increased for asbestos contents below 0.10 percent, where
errors  for the  small  amounts of asbestos emissions become less signifi-
cant from the standpoint of air pollution.

     A gas handling  system was set up to separate, measure, and transfer
samples to the  gas chromatograph.   A step-by-step procedure was prepared.
The non-condensable gases were analyzed by separating the gases on a
Porapak Q column and  then detecting the separated components with a
thermal conductivity  detector.  In some instances, a flame ionization
detector was  also used.   The condensable gases were analyzed by separa-
ting the components on a W-98 silicone gum rubber column and detecting
with a  flame  ionization detector.
     The vehicle tests were carried out during the period May 1 to
November 17,  1972.  Only one major problem occurred during the vehicle
testing:  during the  10-Stop Fade  of vehicle test 1, the hardened steel
ring,on which the rotating seal slides, became loose.  The ring was re-
anchored and  no further problem was encountered during the 15-Stop Fade
or in any further test schedule.  This result showed the durability of
the collector and rotating seal design and construction.  For the 8100
miles of testing, only seven front and eight rotating seals were required.
This was better than  anticipated at the start of the program.  The mileage
accumulations for each schedule of each vehicle test showed that the
mileages were reproducible.
     Prior to  vehicle test 1, a Burnish schedule was performed and the
temperature for the right front disc brake was found to be near 400°F.
The temperature difference,  AT, between the right and left front brakes
was 200-250°F.  This  was unacceptable.  The addition of several thermal
control aids  reduced  the difference to the range 115 to 160°F.  Most
important was the reduction of the right front brake operating tempera-
tures from about 400°F to about 300°F.  The brake shrouding did not
present any problems  on hot days.   During the Detroit Traffic Test, the
AT between the  front  brakes remained between 100 and 140°F while that
for the rear  drum brake  remained between 10 and 30°F.
                                                                     11-3

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      During the fade tests, the right front brake was  programmed accord-
ing to known temperature versus stop-number curves obtained for the  same
friction materials previously run on an inertia  dynamometer and on a
normal test vehicle.  After the seventh stop,  the time  increment between
stops was increased to prevent the right front  brake  from overheating the
friction materials within the shroud.  The 15-Stop Fade produced an  addi-
tional effect within the brake.  The heat generated  was retained within
the shroud and caused the brake fluid within the right  front caliper to
heat.  The resultant fluid boil produced a loss  of pedal for the last
two fade stops and persisted through the first eight recovery stops.

      The recovery of particulate emissions from both front brakes
yielded a comparison of the amounts of emissions of  the normal with  the
shrouded disc brake.  For both brakes, the sump  sample  appeared to reach
and maintain an average amount of debris which was independent of the
mileage.  When the debris was removed, the steady-state value appeared
to reestablish itself.  The surfaces sample for  the  open brake showed
the same behavior.  The recovery data were used  to calculate the distri-
bution weighting factors used later to calculate the distribution of
brake emissions in three categories:  retained in the brake,  released
as road drop-out material, and airborne material.
      The amounts of particulates collected in the three samples were
compared with the friction material weight losses.   In  all  cases,  the
data for the right front brake ranged from approximately 42-percent
recovery in the initial schedule of each vehicle test to approximately
70 percent for the final schedules.  The low initial recovery may have
been caused by excess gassing during Burnish,  resulting in  a lower
recovery of particulates.  The brake emissions recovered from the fade
tests were "tarry", and the surfaces samples were recovered  only with
difficulty.

      The material recovery data for the rear brakes showed  wide vari-
ation.  The problem in part was due to the 80-percent sump  carry-over
to the following test.  During certain vehicle tests, the sump  sample
was redistributed within the brake and registered a  lower value  after
the test.  Thus, a negative weight was recorded.  The other  samples  for
that brake did increase and a positive overall value was  always  recorded.

      The range of asbestos content in the brake emissions  for  vehicle
tests 1 and 2 went from a high of 1.65 percent to a  low of  0.03  percent
for the 90 analyses; only three were above 1.00 percent.  The overall
average for vehicle test 1 was 0.38 percent and  for  vehicle  test 2 was
0.25 percent.  For vehicle test 3, the range of  asbestos  content was
from a high of 0.51 percent to a low of 0.003 percent.   The  overall
average was 0.07 percent.

      To provide a systematic independent check  on the  asbestos  analyses,
the EPA Project Officer arranged a second contract for  Battelle Columbus
Laboratories to analyze twenty-four samples generated during the program.
Johns-Manville also provided three analyses.   The Johns-Manville and
11-4

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Battelle data agreed very well.  In 19 of the 24 analyses, the Program
results  were slightly higher than the corresponding Battelle results.
The Program average was 0.25 percent, while the Battelle average was
0.17  percent or 68 percent of the Program average.  The Program data
were expected to be higher for the following reasons:  all larger fibers
(bundles of fibrils) found were assumed to be cylinders of projected
diameter and length, and a fiber with an elliptical cross section was
actually smaller in volume than reported; and all fibers were assumed
to be 100-percent asbestos (partially degraded asbestos or olivine
fibers were weak and mechanically reduced to non-fibrous material by
the other analytical techniques, hence only the remaining asbestos
fibrils  that remained were counted).

      Analysis of the gaseous emissions was made difficult by the large
quantities of water and carbon dixodie which by-passed the gas condition-
ing trap and entered through the rotating seals.  Most samples showed
traces of GI to 03 hydrocarbons only as lower concentrations of higher
molecular weight gases could not be detected,.  When the gases were con-
centrated from the fade.tests, C^ to Cg compounds such as butanes, ben-
zene, toluene, phenol, and cresols were detected in the gas traps.  The
corresponding shroud extracts showed Ci2 to 630 materials, including
cardanol.

      To compare the emissions properly, it was found necessary to cal-
culate the asbestos emission factors for each sample in micrograms/mile.
The values of these factors were obtained by multiplying the weights of
brake debris generated by the appropriate asbestos percents, then divid-
ing by the miles per test schedule.  Thus, either a high asbestos content
or a large sample gave a high factor.  The following .observations were
made:
      •  asbestos emissions were higher for new friction surfaces and
         decreased with use;
      •  the drum brake produced more asbestos emissions than the disc
         brake initially, the difference decreasing as the friction
         materials continued in use;
      •  heavy (abusive) duty did not necessarily give a higher percent
       - asbestos, however, the large amount of debris produced gave a
         significant rise in asbestos emissions;
      •  asbestos emissions from the brakes were found to decrease from
         fade or heavy-duty stops  (highest) to burnish to moderate
         braking (lowest);
      •  for the disc pads only, there was an increase in asbestos emis-
         sions with increased asbestos content in the friction material
         (there was no such trend for the drum brake materials);
                                                                   11-5

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•
         both  the front  disc pads and the drum linings of vehicle test 3
         have  wear comparable to that found in the other two vehicle
         tests,  yet the  asbestos emissions were significantly lower
         (both pads and  secondary linings contained brass chips which
         may have been in part responsible for the more complete con-
         version of the  asbestos in the brake emissions); and

         for both disc and drum brakes, the surfaces sample was the
         largest of the  three (^92 percent), the sump sample was next
            percent) , and the airborne sample was the smallest (VL percent) ,
Each fade schedule included the 12-stop recovery and a  35-stop  reburnish.
It was expected that the recovery and reburnish stops would  remove  the
heat-damaged rubbing surfaces of the friction materials.  However,  both
the A.F. Baseline and Final Baselines show an average increase  of 250 per
cent more wear over their approximately 350 miles or approximately  1500
stops.  These data indicate that many stops were necessary to produce a
renewed surface.
      The end objective of this report was to develop the best  possible
estimate of total brake and clutch emissions per year for the U.S.  popu-
lation of braked vehicles in use.  A data base was obtained  from a  wide
variety of trade publications and from industry and government  contacts.
The number of vehicles given and the other data presented indicated a
wide and varied usage so that some assumptions had to be made in prepar-
ing the asbestos emissions estimates.

      The asbestos content in brake friction materials was given by the
two most knowledgable industry sources as 90 and 120 million pounds for
1972.  In the program our calculations, ^118 million pounds was  used.
These ^118 million pounds of asbestos were incorporated in 171  million
pounds of brake friction materials.  A calculation gave the total brake
friction material worn away as 117 million pounds per year.  The program
calculation for the asbestos content in clutch friction materials was
4.38 million pounds in 8.76 million pounds of friction material.  A
calculation gave the total clutch friction material worn away as 6.56
million pounds.

      Two series of weighting factors were developed.  The distribution
weighting factors were calculated from the material recoveries  in the
shrouded and unshrouded brakes as indicated earlier.  Estimates were
made for both disc and drum brakes from the test vehicle for the amounts
of the different samples distributed from the brakes.  These estimates
were made for the Burnish schedule, for the end of a complete vehicle
test, and for the end of all three vehicle tests.  For the drum brake,
estimates were made for up to 40,000 miles.  The severity weighting
factors were calculated from the percentages of different braking modes:
for new versus burnished friction materials, for severe (or abusive)
versus moderate braking, and for the renewal of friction surfaces (post-
fade) .
 11-6

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      The  total  asbestos emissions estimate for the test vehicle was
calculated from  the asbestos emissions factors and the severity weight-
ing factors.   The average asbestos emissions factors for the disc brakes,
drum brakes,  and clutch were used along with the Burnish (new surfaces),
A.B. Baseline (surfaces preparation), Detroit Traffic (moderate braking),
10-Stop Fade  (severe braking) and A.F. Baseline (surface renewal) weight-
ing factors.   The value obtained for the test vehicle was 28.51 yg/mile.
      The  total  asbestos emissions were not considered to be merely
dumped onto the  ground or thrown into the atmosphere.  The fates of the
emissions  were calculated with the use of the distribution weighting
factors as follows:

                 Road Drop-out            81.9 percent
                 Airborne                  3.7 percent
                 Brake Retention          14.4 percent

      The  annual total asbestos emissions estimate for 96,400,000 passen-
ger vehicles  travelling .an average of 9,978 miles per year was found to
be 60,400  pounds distributed as follows:

                 Road Drop-Out            49,470 pounds

                 Airborne                  2,230 pounds

                 Brake Retention           8,700 pounds

                                          60,400 pounds

      Truck brakes usually tend to generate and to operate at higher
temperatures  than passenger cars.  To estimate asbestos emissions for
light, medium, and heavy trucks, it was found necessary to adjust the
severity under which the emission would be expected to occur.  The
severity weighting was obtained by using a larger fraction of the 10-
Stop Fade  (and A.F. Baseline) asbestos emissions according to the
following  progression:
              Passenger car                    2.0 percent

              Light truck                      5.0 percent

              Medium truck (and bus)          10.0 percent

              Heavy truck                     15.0 percent
In addition,  it  was necessary to estimate the asbestos emissions factors.
Assuming that these factors were roughly proportional to the increased
friction material weights of the appropriate vehicles compared to the
test vehicle, the following estimated factors were determined:

                                  Front           Rear
                                Drum Brake     Drum Brake     Clutch

     Light truck                   2.0             3.0           2.0

     Medium truck (and bus)        3.0            10.0           4.0

     Heavy truck                   5.0            30.0           6.0
                                                                    11-7

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      The annual total asbestos  emissions  estimates  for light trucks,
medium trucks  (and buses) and heavy  trucks were  found  to be:

            Light trucks                   32,300 pounds

            Medium trucks (and buses)      16,300 pounds
                                           32,900 pounds
Heavy trucks
                                          81,500  pounds
      The distribution weighting factors for  trucks were  calculated based
on the following considerations.  The truck drum brake  is designed to be
more open than the car drum brake and in many instances no splash shields
are used.  Based on the estimates, that only  about 25 percent  as much
debris remains in a truck drum brake as compared to a passenger car drum
brake, distribution weighting factors for trucks were estimated.  The
distribution of the total asbestos emissions  estimate was as follows:
                 Road Drop-Out

                 Airborne

                 Brake Retention
                              87.9 percent

                               2.9 percent

                               9.2 percent
      The summary of the estimated asbestos emissions for all vehicles
in pounds/year was calculated as follows:
   Passenger Cars

   Light Trucks

   Medium Trucks
     (and buses)
        Total Asbestos
          Emissions

            60,400

            32,300

            16,300
                                              Distribution

                                     Drop-Out   Airborne   Retention
49,470
28,420

14,330
2,230
  940

  470
8,700
2,940

1,500
Heavy Trucks
Miscellaneous
Distribution by
32,900
16,300
158,200
percent :
28,920
14,330
135,470
85.6%
950
470
5,060
3.2%
3,030
1,500
17,670
11.2%
These estimates should be considered as maximum values.

      The total asbestos emission estimates, and especially the airborne
emissions estimate, are considerably lower than the 540,000 pounds esti-
mated by IIT Research Institute. (ia~1;L)
11-8

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                             APPENDIX A

                      WEAR DEBRIS  CALCULATIONS
A.I   INTRODUCTION

      This  appendix  discusses  friction material reactions used to estimate
amounts  of  wear debris which were expected to have been collected during
various  cycles of the "Brake Emissions" program.   Consideration is given
to both  disc and drum brakes.

A. 2   FRONT DISC BRAKE

      A. 2.1  Composition

             From previous studies,  the typical composition of a disc
pad can  be  approximated:
Resin -\
Cashew I
Rubber J
Asbestos
Zinc

^32 wt %

^64 wt %
^4 wt %
      A.2.2   Burnished Products

             From various  studies,  the following amounts of burnished
products  can be estimated.

             «  Particulates                           Gravimetric
                                                         Factor
                Resin   ^             Carbonaceous
                Cashew  I ^32 wt  %  -> Binder               0.50
                Rubber  J               ^16  wt  %        (from TGA)
                Asbestos  ^64 wt  %  -»• Olivine              0.86
                                        ^55 wt  %        (from TGA)

                Zinc      ^4 wt %  -»• ZnO                  1.25
                                         ^5 wt  %        (from TGA)

                               Total    76 wt  %

Consequently, the expected amount  of particulate wear debris expected
is 76%  of the weight lost.  Although disc wear  does  occur,  it cannot  be
estimated at this time.

             •  Gaseous Products

                The average organic molecule can be assumed
                to have the structure:
                                                                     A-l

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                      — GIL
                                      C9H1()ON
                         CH =  CH-NH
which undergoes the following oxidation reaction:
                C9H1QON + 11.5 02 -»• 9  C02 + 5  H20 + NO

               MW =  148   MW = 32
From the above calculation, only 50% of  the  organic  portion oxidized:
                         32 wt % x 0.50 =  16 wt
which gives 16/148 = 0.108 mole of organic oxidized.   This  requires:
                    11.5 x 0.108 = 1.24 moles  of  0,
                     1.24 x 32.0 = 39.7 gins of 0,
Total amount of material reacting:
                        16.0 + 39.7 = 55.7 gms
Conversion factor is:
                              55.7
                              16.0
= 3.48
A-2

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Since not all 16.0 gms of  the  organic portion will be  completely oxidized
to gases, this value  represents  a maximum  amount  of material expected.
The expected amount of gaseous wear  products is 56% of the weight lost.

     A.2.3   Typical Disc Brake Wear Rates
             Burnish:           ^0.007"  or  ^0.018 cm
             Detroit Traffic:  ^.020"  or  ^0.051 cm
             SAE Fade:          M3.030"  or  ^0.076 cm
             7  Stop, 90 mph:    ^0.015"  or  ^0.038 cm
      A.2.4    Disc  Pad  Area
                              2
              Inner:    8.50 in
              Outer:  11.25 in2
                      19.75  in2
                 19.75  in2  x  (2.54  cm/in)2  =  127.5  cm2
      A.2.5    Calculated  Wear  During  Burnish


              Area x  Thickness -  127.5  x  0.018  =  2.30  cc


                 Typical  S.G.  for disc  pad is 1.70

                 Calculated weight loss:


                       2.30 x 1.70 = 3.91 gms


              «   Particulate Portion


                       3.91 x 0.76 = 2.97 gms


which will be  collected in four areas:

                 sump
                 brake surfaces
                 8.0M filter
                 0.2y filter
                                                                    A-3

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                 Gaseous Portion
                        3.91 x 0.56 = 2.19
which will be collected in three traps:
Wear Particulates
(inch/cm) (gms)

affic

mph
0.007/0.018
0.020/0.051
0.030/0.076
0.015/0.038
2.97
8.47
12.70
6.36
Gases
(gms)
2.19
6.26
9.38
4.68
Total
5.16
14.73
22.08
11.04
                 one condensable gas trap
                 two noncondensable gas traps filled with charcoal

                 Total Sample Expected
                        2.97 + 2.19 = 5.16 gms.

      A.2.6   Summary of Typical Wear Expected


         Test

    Burnish

    Detroit Ti

    SAE Fade

    7 Stop, 9(


A.3   REAR DRUM BRAKE

      A.3.1   Composition

              From previous studies, the typical compositions of primary
and secondary linings can be approximated:

                          Primary    Secondary
              Resin  "\
              Cashew j      28           31

              Asbestos      72           69

      A.3.2   Brake Parameters

              Designation:    11 x 2-1/4" DSSA

              Primary Area:   2.25" x 8.8" (average arc length)
                              = 19.8 in2

              Secondary Area: 2.25" x 11.5" (average arc length)
                              = 25.9
 A-4

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higher  torque stops.

             (The  total lining length is 8.8 + 11.5 = 20.3".  The actual
drum circumference  is  3.14 x 11" = 34.6".  Thus the lining sweeps 20.3/
34.6 x  100  = 59%  of the available drum surface.)

     A.3.3  Burnished Products

             Because  the secondary is programmed to absorb more torque
and essentially wear more throughout the lining combination's usage, and
because the primary and secondary wear debris contributions are always
combined, a more  typical starting composition for the combination must
be slanted  toward the  secondary's composition analysis:
                iin  ^
                ihew  f
*esjn   I   30 wt %
Cashew
              Asbestos     70 wt %

The following amounts  of burnished products can be estimated:

              •  Particulates
                                                       Gravimetric
                                                          Factor

                 Resin  \    or>    „/   Carbonaceous
                 _  ,    7    JU Wt 7o "*•„.,                r\ cr\
                 Cashew J              Binder              0.50
                                         ^15 wt %

                 Asbestos     70 wt % -> Olivine
                                         ^62 wt %          0.90

                                          77 wt %

              •  Gaseous Products
                 The average organic molecule can be assumed to be:

                            OH

                             I               C10H10°2
                                                      OH
                                                                     A-5

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which undergoes the following oxidation reaction:
                   C10H10°2 + n'5 °2 * 10C°2 + 5H2°
                   MW = 162
Since only 50% of the organic portion is oxidized, i.e., 15 wt %, this
corresponds to 15/162 = 0.093 mole oxidized which in turn requires 11.5 x
0.093 x 32 = 34.3 gms of oxygen.  The total amount of reactants is 15.0 +
34.3 = 49.3 gms which represent a gravimetric factor equal to:
                              15.0
      A. 3. 4   Typical Drum Rear Wear Rates

              Burnish:          MD.005"  or  ^0.013 cm
              Detroit Traffics   0.010"  or   0.026 cm
              SAE Fade:         ^0.008"  or  ^.020 cm
              7 Stop, 90 mph:    0.005"  or   0.013 cm
      A. 3. 5   Drum Brake Lining Areas

              Primary:     19.8 in2
              Secondary:   25.9 in^
                           45.7 in2
                   45.7 in2 x (2.54 cm/in)2 = 297 cm2
      A.3.6   Calculated Wear During Burnish

                 Volume = Area x Thickness
                        = 297 x 0.013
                        = 3.86 cc

                 Typical S. G. is 1.70

                 Calculated weight lost:
                        3.86 x 1.70 = 6.56 gms
A-6

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         •  Particulate Portion
                    6.56  x 0.77 = 5.15 gms
          «   Gaseous  Portion
                    6.56 x 0.49 = 3.21 gms
          «  Total Wear Debris
                    5.15 + 3.21 = 8.36 gms
  A.3.7   Summary of Typical Wear Expected

     Test
Burnish
Detroit Traffic
SAE Fade
7 Stop, 90 mph
   Wear
 (inch/cm)
0.005/0.013
0.010/0.026
0.008/0.020
0.005/0.013
Particulates    Gases    Total
   (gms)        (gms)    (gms)
    5.15        3.21      8.36
   10.30        6.42     16.72
    8.24        5.13     13.37
    5.15        3.21      8.36
                                                                 A-7

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                               APPENDIX B

   NUCLEPORE FILTER FLOW CHARACTERISTICS FOR BRAKE LINING WEAR DEBRIS


B.I   INTRODUCTION

      This appendix describes  a series of experiments used to define the
filter flow characteristics  of Nuclepore membranes with varying loadings
of brake lining wear debris.   Figure B-l is a schematic of the experi-
mental setup.

B.2   FLOW VERSUS PRESSURE DROP

      Table B-l is  the  compilations  of flow versus pressure drop data
for both unloaded filters and  loaded filters containing approximately
1.0 gram of wear debris (from  a 1970 Chrysler Imperial rear drum brake).
This data is plotted in Figure B-2.

B.3   FLOW AND PRESSURE DROP VERSUS  LOADING

      Table B-2 is  the  flow  and pressure drop variations versus filter
loading data at a fairly high  initial pressure drop setting while
Table B-3 is similar data for  a lower initial pressure drop.   The data
are plotted in Figure B-3.   The initial and final (with approximately
1 gram loading) pressure drops and flows for this data are identified
as Runs 3 and 4 on  Figure B-2.

B.4   MATERIAL BALANCE  DATA

      Additional Table  B-2 Data:

      • Amount of  debris added to system:                     1036.0 mg
        Amount of  debris collected  on filters:                1000.6
                                        'If                      " - — - -
        Amount of  debris lost  in  system :                       35.4 mg
          *
           some spillage, most remains on
             walls  of  tube leading  from
             funnel  to filter  holder.
      • Removal of  8y  membrane from under  debris
                              after  light shaking:              15.3 mg
         Original weight:                                       14.1
         Amount remaining on  filter:                             1.2 mg

      • Removal of  8y  membrane from under  debris
                                     and air blow:              14.7 mg
         Original weight:                                       14.1
         Amount remaining on  filter:                             0.6 mg
                                                                   B-l

-------
             MERCURY
             MANOMETER
                                      FUNNEL
                                         8/J FILTER
                                                    FLOWMETER
                                              CONTROLLED
                                                  LEAK
                                                 PUMP
   Figure B-l -  Sketch of Experimental  Setup for Defining  Filter Flow
                 Characteristics of Nuclepore Membranes
B-2

-------
            Table B-l -  Flow Versus  Pressure Drop Data
Unloaded Filter?
Run 1
Flow (CFIi)
0.9
2.3
3.8
5.9
7.7
9.7
11.0
12.0
AP (cm Hg)
1.0
3.4
6.2
11.0
16.6
23.9
28.9
33.4
Run 2
Flow (CFM)
0.9
2.3
3.8
7.7
9.7



AP (cm Hg)
1.0
3.7
6.5
17.1
24.2




Loaded Filter
Run 1
Flow (CFII)
0.9
2.0
3.0
4.0
5.0
7.0
9.0
11.0
12.0
AP (cm Hg)
1.0
3.1
4.1
7.2
9.6
15.2
22.7
30.6
35.6
12'
10'
                                              UNLOADED:
                                              • RUN 1
                                              A RUN 2
                                              O RUN 3
                                              O RUN 4
LOADED
O RUN 1
• RUNS
• RUN 4
                         12       16       20

                             PRESSURE DROP (CM HG)
                                                 24
                                                         28
                                                                 32
                                                                         36
            Figure  B-2 - Plot  of Flow Versus Pressure Drop
                                                                        B-3

-------
           Table B-2  - Flow and  Pressure Drop  Versus Loading Data
Wear Debris
Reservoir Weight
(gm)
13.0160
13.0025
12.9744
12.9528
12.8883
12.7911
12.5590
12.3547
11.9800
AW
(rag)
—
13.5
28.1
21.6
64.5
97.2
232.1
204.3
374.7
Filter
Loading
(mg)
0.0
13.5
41.6
63.2
127.7
224.9
457.0
661.3
1,036.0
Pressure Drop
(cm Hg)
52.7 - 27.6 = 25.1
51.4 - 28.8 = 22.6
51.3 - 28.9 = 22.4
51.1 - 29.2 = 21.9
50.7 - 29.6 = 21.1
50.4 - 29.9 = 20.5
50.3 - 30.0 = 20.3
50.1 - 30.2 = 19.9
50.0 - 30.3 = 19.7
Flow
(CFM)
9.4
9.0
9.0
8.8
8.7
8.4
8.3
8.2
8.0
   25-7
C3
X

o

0.
o
oc
a
UJ
cc
UJ
oc
a.
15
   10'
                   20
                                            O PRESSURE DROP

                                            A FLOW
                                 40            60


                                 FILTER LOADING (MG)
                                                          80
                                                                            10
                                                                             H
                                                                             -n
                                                                           100
      Figure B-3 - Plot of Pressure Drop and Flow Versus  Filter Loading
  B-4

-------
       Table B-3 - Flow and Pressure Drop Versus Loading Data
Wear Debris
Reservoir Weight
(gm)
13.7892
13.7741
13.7590
13.7416
13.7012
13.5552
13.3928
13.5198
12.8014
AW
(mg)
—
15.1
15.1
17.4
40.4
146.0
162.4
233.0
358.4
Filter
Loading
(mg)
0.0
15.1
30.2
47.6
98.0
234.0
396.4
629.4
987.8
Pressure Drop
(cm Hg)
43.3 - 36.9 = 6.4
43.3 - 36.9 - 6.4
43.2 - 36.9 = 6.3
43.2 - 36.9 = 6.3
43.2 - 36.9 - 6.3
43.2 - 36.9 - 6.3
43.2 - 37.0 = 6.2
43.2 - 37.0 = 6.2
43.2 - 37.0 = 6.2
Flow
(CFM)
3.8
3.7
3.7
3.7
3.7
3.7
3.7
3.7
3.6
     Additional Table B-3 Data:

     •  Removal of 8y membrane from under debris
                after light shaking and air blow:
         Original weights
         Amount remaining on filter:
     •  Weight of funnel plus tubing plus debris:
         Weight of funnel plus tubing:
         Weight of debris trapped:

B.5   CONCLUSIONS
    14.9 mg
    13.4
     0.6 mg

43,187.0 mg
43,144.8
    42.2 mg
     •  The flow rate through the filters is fairly reproducible
        for different membranes.
     •  Gas flow is proportional to pressure drop.
                            2
     •  Initial 1 to 2 mg/cm  loading reduces flow slightly
        (^10 percent).
                                       2
     •  Higher loading (up to 100 mg/cm ) reduces flow an
        additional 10 percent.
     *  Wear debris can be separated from membrane and stored
        in a vial without any significant loss.

-------
         Minimal losses will occur in the heated transfer line
         between the shroud and the filter holder.
         Over-all filter setup chosed for this project appears
         to operate satisfactorily for approximately 1 gram of
         collected debris.  Larger amounts will require a pre-
         filter of several filter changes.
B-6

-------
                             APPENDIX C
              COLLECTION OF BRAKE AND CLUTCH EMISSIONS


Sequence                              Description

   1          Preparation of Collection Systems  (Table C-l)

   2          Installation of Collection  System, on Test Vehicle  (Table C-2)

   3          Preparation of Vehicle  for  Test  (Table C-3)

   4          Vehicle Test (Table C-4)

   5A        Removal of Particulate  Filters and Gas Collectors  from
             Vehicle (Table C-5)

   5B        Removal of Wear Debris  from Disc Brake Emissions Collector
             (Table C-6)

   5C        Removal of Wear Debris  from Drum Brake Emissions Collector
             (Table C-7)

   5D        Removal of Wear Debris  from Clutch Emissions Collector
             (Table C-8)

   6          Transfer of Samples to  Analytical  Laboratories  (Table C-9)
                                                                     C-l

-------
n
                         Table  C-l - Preparation of Collection System for Vehicle Test - Sequence 1
                             Operation
 Location
Responsibility
       Remarks
              Gas  Collection  System
                Rinse  interior of condensable gas trap
                 (only) with  toluene  (three rinses;
                ^25  cc per rinse).  Air dry.  Assemble
                trap train.  Check all connections.
                Heat trap train in vacuum oven at
                100°C for one hour at vacuum (all
                valves open).
                Remove from  oven and close valves.

              Clean,  Label, and Weigh Vials
             Particulate Filter Holders

                Remove 0-ring, wipe clean with
                toluene.  Air dry.

                Rinse filter holders with toluene
                until clean.  Air dry.

                Replace 0-ring in holder.

                Weigh  filter membranes.
                Reassemble particulate collection
                system.
Laboratory




Laboratory



Laboratory

Laboratory
Technician



Technician


Technician

Technician
Laboratory
Laboratory
Laboratory
Technician
Technician
Technician
Remove high molecular
weight materials.
Remove residual gases
from previous test.
For wear debris:
   Sump sample
   Surfaces sample
   Additional
Removes  sludge.
From desiccator.

-------
                               Table C—2 - Installation of Collection Systems -  Sequence 2
n
Operation
Pick Up Gas Collection Systems (3) ,
Particulate Filter Holders (3) , and
Vials with Laboratory Cart.
Cover with plastic sheet for
transportation to garage.
Install Gas Collection Systems
(Three Systems)
Connect ends
Connect thermocouples
Check temperatures
Check inlet air drier and filters
Install Particulate Filter Holders
(Three Systems)
Hoist vehicle
Connect ends, pack insulation,
tighten clamp
Connect thermocouples
Connect heater
Check heating (50% power)
Record temperatures
Assemble Emissions Collectors
Front
Rear
Clutch
Location
Laboratory/
Garage

Garage

Garage






Garage



Responsibility
Driver

Driver

Driver






Driver



Remarks
Handle with care during
transportation.

Front Brake 1 or 2
Rear Brake 3 or 4
Clutch 5 or 6
(1, 3, 5 or 2, 4, 6 are
on the same tests - do
not change or mix.)













-------
n
-P-
Table C-3 - Preparation of Vehicle for Test  -  Sequence  3
                            Operation
             Prepare Record Sheets


             Check Vehicle (Gas,  Oil, Tires, Etc.)

             Fill Trap Boxes With Dry Ice


             Fill Dry Ice  Storage Box (in
             Vehicle Trunk)

             Check Trap Temperatures
                Front
                Rear

                Clutch
             Check Battery and Inverter Electrical
             System

             Check Thermocouples, Brake Counter,
             Brake Gages,  etc.

             Disconnect  Battery Charger

             Start Engine, Restart Inverter,
             Record Odometer

             Adjust Air  Flows
                Front
                Rear
                Clutch
                          Location
                           Office


                           Garage

                           Garage


                           Garage


                           Garage
                           Garage


                           Garage


                           Garage

                           Garage


                           Garage
Responsibility
Driver/
Test Engineer

    Driver

    Driver


    Driver


    Driver
    Driver


    Driver


    Driver

    Driver


    Driver
       Remarks
Review scheduled test.
Handle with scoop or
gloves.
Must be colder than
-70°C (-94°F).
To ensure safe engine
start.
To ensure proper collec-
tion efficiency.

-------
                                          Table C-4 - Vehicle Test  -  Sequence  4
                            Operation
O
In
             Check Vehicle Test Record Sheets


             Drive to Test Area

             Record Time,  Mileage,  Reset Brake
             Counter

             Record All Temperatures and Air Flows

             Perform Test


             Monitor Brake Temperature Balances (R to L)

             Record Maximum and Minimum Temperatures

             Monitor Emissions

                Collectors:

                   Check flows
                   Check temperatures

                      Cold Boxes
                      Particulate heaters

             Return Vehicle to Garage With Brake
             Temperatures Below 200°F.
Location
Vehicle


Vehicle

Vehicle


Vehicle

Vehicle


Vehicle

Vehicle

Vehicle
Vehicle
Responsibility
Driver/ -
Test Engineer
Driver/
Test Engineer

    Driver

    Driver

    Driver
    Driver
       Remarks
Prepared prior to test.
Periodically


Periodically

Periodically

Periodically

-------
n
ON
Table C-5 - Removal of Partlculate Filters and Gas Collection from Vehicle - Sequence 5A
Operation
Park Vehicle in Garage Over Hoist
Stop Engine
Record Odometer and Brake Counter
Close All Valves in Gaseous
Collection System
Turn Off Heaters
Close Garage Door
Check Gaseous Collection System and Top
Up Dry Ice
Remove Gaseous Collection Systems and
Place on Cart (Clean)

Hoist Vehicle
Remove Particulate Collection Systems and
Place on Cart (Onto Shock-Proof Pad) .
Location
Garage
Garage
Garage
Garage
Garage
Garage
Garage
Garage

Garage
Garage
Responsibility
Driver
Driver
Driver
Driver
Driver
Driver
Driver
Driver

Driver
Driver
Remarks
Immediately after com-
pletion of test.
Immediately after com-
pletion of test.
immediately after com-
pletion of test.
Immediately after com-
pletion of test.
Immediately after com-
pletion of test.
Immediately after com-
pletion of test.
Immediately after com-
pletion of test.
Check and ensure valves
are closed. Label lo-
cation and run number.

Handle with care. Do
not bump.

-------
                   Table C-6 - Removal of Wear Debris from Disc Brake Emissions  Collector - Sequence 5B
                            Operation
Location
Responsibility
       Remarks
             Adjust Vehicle on Hoist
             Remove Wheel.   Visually Inspect Collector
             and Rotating Seal.

             Clean Exterior Surfaces.

             Spread 4x5 foot Clean Plastic Sheet
             Below Wheel Well.

             Spread 12" x 18" Clean Plastic Sheet Under
             Collector Shroud.  Place Clean Vial Onto
             Sheet.

             Carefully Remove
                Rubbing seal and inspect
                Screws
                Outboard shield

             Vacuum Debris From Outboard Shield, Rotor,
             and All Other Brake and Collector Surfaces
             onto 0.2p Nuclepore filter.  Remove Caliper
             Cover Plate and Vacuum.  Transfer Filter
             to Vial.
 Garage


 Garage


 Garage

 Garage


 Garage



 Garage




 Garage
    Driver


    Driver


    Driver

    Driver


    Driver



    Driver
  Technician
Wheels should be 1 to
2 inches above floor.

Record observation.
To protect clean smaller
sheet to catch debris.

To catch wear debris.
Vial previously cleaned
and weighed.

Record inspection.
Label:
   Location
   Surfaces Sample
   Vehicle Test No.
   Schedule
o
i
                                            (1 of 2)

-------
n
00
                   Table C-6 - Removal of Wear Debris from Disc Brake Emissions  Collector  -  Sequence  5B
                            Operation
 Location
Responsibility
       Remarks
             Replace Plastic Sheet Under Open
             Collector.
  Garage
             Remove Both Caliper Bolts and Remove
             Caliper.  Vacuum the Pad Debris Onto 0.2y
             Nuclepore Filter.  Vacuum Wear Debris From
             Rivet Holes and From Inside of Caliper
             Piston.

             Remove Pads From Shoes.

             Dry,  Weigh and Mike the  Pads
             Reassemble Brake and Collector.
  Garage
Laboratory

Laboratory



  Garage
  Technician
  Technician
  Technician

    Driver



    Driver
Label:
   Location
   Sump Sample
   Vehicle Test No.
   Schedule
Weigh to nearest 0.01 gm.
Use SAE micrometer
procedure.
                                                                                                          (2  of  2)

-------
                   Table C-7 - Removal of Wear Debris From Drum Brake Emissions Collector -  Sequence  5C
                            Operation
Location
Responsibility
       Remarks
             Remove Wheel.  Visually Inspect Rotating
             Seal.

             Clean Exterior Surfaces.

             Spread 4' x 5' Clean Plastic Sheet
             Below Wheel Well.

             Spread 12" x 18" Clean Plastic Sheet
             Under Collector (Shroud).

             Carefully Remove Drum and Set Down With
             Opening Facing Up.

             Collect Sump Sample Including Debris From
             Brake Shoe Rivet Holes and Place Into Vial.
             Vacuum Brake Surfaces and Drum Interior
             Onto 0.2y  Nuclepore Filter.  Collect
             Wear Debris on First Plastic Sheet and
             Put Into Vial.  Dismantle Brake and
             Vacuum all Parts.  Vacuum Backing Plate.
             Transfer Filter.
 Garage


 Garage

 Garage


 Garage


 Garage


 Garage
    Driver


    Driver

    Driver


    Driver


    Driver


  Technician
 Garage
  Technician
Record observations.
Label:
   Location
   Sump Sample
   Vehicle Test No.
   Schedule

Label:
   Location
   Surfaces Sample
   Vehicle Test No.
   Schedule
n
vo
                                           (1 of 2)

-------
Table C-7 - Removal of Wear Debris From Drum Brake Emissions  Collector - Sequence 5C
Operation
Remove Linings From Shoes .
Dry, Weigh, and Mike Linings.
Reassemble Braise .
Return 80% of Sump Wear Debris to
Drum Surface.
Replace Drum Assuring that no Debris
Falls Out.
Reassemble Collector (Shroud)
Components
Location

Garage
Garage
Garage
Garage
Garage
Responsibility

Driver
Driver
Driver
Driver
Driver
Remarks

Record weights.
Wipe away any hydraulic
oil.
Need for drum grinding
action.


                                                                                      (2 of 2)

-------
                      Table C-8  -  Removal  of Wear Debris From Clutch Emissions Collector - Sequence 5D
                            Operation
n
             Adjust Vehicle Height.

             Carefully Clean Exterior Surfaces

             Spread 4' x 5' Clean Plastic Sheet
             Below the Clutch.

             Spread 12" x 18" Clean Plastic Sheet
             Under Clutch

             Remove Clutch Cover.

             Vacuum Debris Onto 0.2y Nuclepore Filter.
             Transfer to Vial.
             Carefully Vacuum.  All Other  Surfaces
             Wear Debris.
Weigh and Mike the Clutch Facing Assembly
(at Start of First Vehicle Test and at
Finish of Last Vehicle Test).

Reassemble Clutch and Collector (at Start
of First Vehicle Test and at Finish of
Last Vehicle Test).
                                              Location
                                               Garage

                                               Garage

                                               Garage


                                               Garage


                                               Garage

                                               Garage
                                               Garage
                                                            Garage
                                                            Garage
Respons ib illty
    Driver

    Driver

    Driver


    Driver


    Driver

    Driver
    Driver
    Driver
    Driver
       Remarks
Label:
   Location
   Sump Sample
   Vehicle Test No.
   Schedule.

Caution:  oil mist on
          surfaces.
Label:
   Location
   Surfaces Sample
   Vehicle Test No.
   Schedule

Record weight.

-------
N>
                         Table C-9  -  Transfer  of  Samples to Analytical Laboratories - Sequence 6
                            Operation
 Location
Responsibility
       Remarks
             Ensure All Samples  are  on  Cart and
             Protected  From Possible Shaking in
             Transfer to Labs

             Cover  Cart With Plastic Sheet

             Transfer Cart  and Samples  to Analytical
             Lab

             Check-In All Samples and Verify
             Identification
  Garage



  Garage

Laboratory


Laboratory
  Technician



  Technician

  Technician


  Technician
Report to project
engineer

-------
Sequence
                              APPENDIX D

               ANALYSIS OF BRAKE AND  CLUTCH  EMISSIONS
   7A        Process Particulate Filters  (for Material  Balance  Considera-
            tions) (Table D-l)

   7B        Redistribution of Particulates  for Microscopy  (Table D-2)

   8A        Particulate Analysis by Optical Microscopy (Table  D-3)

   8B        Particulate Analysis by Electron Microscopy (Table D-4)

   9         Asbestos Emissions and Size  Distribution  (Table  D-5)

  10A        Noncondensable Gaseous Emissions Processing (Table D-6)

  10B        Analysis of Noncondensable Gaseous Emissions  (Table D-7)

  11A        Condensable Gaseous Emission Processing  (Table D-8)

  11B        Analysis of Condensable Gaseous Emissions  (Table D-9)

  12         Total Gaseous Emissions (Table  D-10)
                                                                     D-l

-------
                        Table  D-l - Processing Particulate Samples  - Sequence 7A
              Operation
 Location
                   Responsibility
                                                                                                  Remarks
 Airborne Samples

    Remove Filter Membrane From Filter
    Holders Over Clean 12" x 12" Plastic
    Place Filter Membranes Into Clean
    Vial.  Brush Loose Debris Into Vial.

    Accumulate Filter Membranes Pertinent
    to Same Test.
All Samples

   Desiccate All Filter Membranes  and Vials
   of Particulates.

   Weigh All Samples

   Select Samples for Division for
   Battelle.  Divide samples,  Pack,
   and Ship.

Low Temperature Ashing (LTA)

   Randomly Select 20 to 50 mg of  Wear
   Debris From Vial  and Distribute in
   Thin Layer Over LTA Boat.

   Insert Into LTA.   Initiate  Plasma.

   Remove After 7 Hours and Redistribute
   Wear Debris in Boat.

   Insert Into LTA.   Initiate  Plasma and
   Remove After Further 17 Hours.

   Redistribute Wear Debris and Insert
   Into LTA for additional 24  Hours.
Laboratory
Laboratory
Laboratory


Laboratory

Laboratory
Laboratory



Laboratory

Laboratory


Laboratory


Laboratory
                     Technician
   Technician
   Technician
   Technician

Project Engineer
   Technician
   Technician



   Technician

   Technician


   Technician


   Technician
                     Use extreme care.   Work  in
                     draft-free, ultra—clean  area.
                     Some vehicle tests  may have
                     two or more filter  sets
                     (i.e., Detroit  Traffic Test).
Record on test sheet.

Record selections.  Use
extreme care.
Record weight and time.
Expose new surfaces to
plasma.
                     Record weight loss after
                     48 hours elapsed LTA time.

-------
                  Table D-2 - Redistribution  of Particulates for Microscopy - Sequence 7B
               Operation
 Location
                  Responsibility
                                                Remarks
For each LTA Sample Weigh 0.55  + 0.05 mg
Onto Tiny Platinum Boat by Taking Several
M).05 mg Fractions from LTA Sample.

Suspend in 100 cc of 1:1 MethanoliMEK in
250 cc Beaker
Filter Onto 47 mm O.D.  0.2u Nuclepore
Membrane:

   Swirl Solution and Rapidly Pour Into
   Funnel.

   Start Vacuum and Then Stop Solution
   Level About 1/2 cm above Filter.

   Wash Down Beaker and Add to Funnel

   Start Vacuum and Again Stop Level
   1/2 cm above Filter.

   Wash Down Funnel Sides with Solvent.
   Allow Last Wash to Filter to
   Completion.

   Cover Top of Funnel with a Clean
   Petri Dish Top and Pull Vacuum
   for 5 Minutes.

   Remove Filter and Store in Petri Dish.
Laboratory
Laboratory
Laboratory

Laboratory


Laboratory

Laboratory


Laboratory



Laboratory



Laboratory
                    Technician
Technician
Technician

Technician


Technician

Technician


Technician



Technician



Technician
                   Preserve  sample distribution.
Use pre-filtered solvent.   Use
very clean beaker (rinsed with
solvent).
Preserve random distribution.

Do not allow to dry.  Use 3-way
stopcock to control vacuum.
Do not allow to dry.   Use 3—way
stopcock to control vacuum
Cover keeps dirt out.   Can  also
be used in above steps  between
washings.

Insure sample is labeled properly.

-------
u
-P-
                                  Table D-3 - Particulate Analysis  by Optical Microscopy  - Sequence 8A
                            Operation
               Sample Preparation

                  Insure Dust and Draft-Free Ambient
                  Conditions.

                  Label a Clean Slide With a Frosted
                  End for Easy Sample Identification.
                  Rinse With Filtered Acetone.

                  Place 1 Drop of Solution With
                  Refractive Index 1.585 in Center  of
                  Slide and Smear Into a Shape Corres-
                  ponding to a Typical Filter Section.

                  Cut a Circular Section From Nuclepore
                  Filter.  Handl With Forceps.  Place
                  Nuclepore Filter on Top of Solution
                  on Glass Slide.
                 Cover with Corning No.  1  Cover  Slip
                 (24 x 40 mm)  to Flatten the  Filter
                 Paper and Hold the Mounting  Medium
                 in Place.

                 Store Sample in a Petri Dish or Slide
                 Box Until Counting Takes  Place.
                                                                Location
Metallurgical Lab.
Metallurgical Lab.
Metallurgical Lab.
Metallurgical Lab.
Metallurgical Lab.
Metallurgical Lab.
                       Responsibility
Microscopist
Microscopist
Microscopist
Microscopist
Microscopist
Microscopist
                                                                                                                 Remarks
To reduce static charge of
filters, use either of the
following:

  a-emitter such as those sold
  by photographic houses to clean
  camera lenses.

  Ether-soaked swabs passed in
  air over the filter so that
  vapor will dissipate charge.

Remove all bubbles.
                                                                                                                                  (1 of 2)

-------
                                  Table D-3 - Particulate Analysis by  Optical Microscopy -  Sequence  8A
                            Operation
     Location
                        Responsibility
                                                       Remarks
            Counting  Procedure

               Fill Out  Count Sheet  (Exhibit D-I).

               Set Up Microscope With Heine Phase-
               Contrast  Optics  at  400X.

               Calibrate the Microscope by the
               Following Procedure.  The Length of the
               Large  Reticle is 200  L Units.  By Measur-
             '  ing the Actual Length of the Rectangle
               Using  the Stage  Micrometer and Dividing
               This Value by 200,  the Value of L at the
               Magnification is Obtained.

               Place  a Sample Slide  on the Stage and
               Focus  on  the Top Surface of Filter.
               The Total Fiber  Count Should be at
               Least  100 Fibers or 100 Fields, Which-
               ever  is Less.
               Count All Fibers Crossing the  Limits
               of the Counting Field on Two Adjacent
               Sides (Top and Left).
               Record the Counts Into the Various
               Size Ranges Given on the Count  Sheet.
    Laboratory

Metallurgical Lab.


Metallurgical Lab.
Project Engineer

  Microscopist


  Microscopist
Metallurgical Lab.
  Microscopist
Metallurgical Lab.
  Microscopist
With this value for L,  the actual
diameter for each circle and the
length of each individual area
can be obtained for fiber sizing.
This sketch shows the distribution
of 100 fields over several  areas
easily scanned by stage movement.
During the count  of  each field, it is
important to constantly adjust the
fine focus back and  forth.  This
brings into focus the  fibers that
might not be seen otherwise.
                                                                                                                                 (2 of 2)
Ui

-------
                   Table D-4 -  Particulate Analysis by  Electron  Microscopy -  Sequence  8B
              Operation
                                                   Location
                       Responsibility
                                                                                                    Remarks
Sample Preparation

   Cut Out a 1/2  inch Filter Circle of
   Nuclepore Filter With a Special
   Cutter and Mount on a Glass Microscope
   Slide With Scotch Tape.

   Coat the Piece of Filter with Carbon
   in a Vacuum Coater.
Metallurgical Lab.
Metallurgical Lab.
                         Technician
Technician
   Use  a Drop of Diffusion Pump Oil on
   Porecelain Plate to Determine Carbon
   Film Thickness.

   Prepare Copper Grids (400 Mesh).

   For  Each Filter Sample, Place 2 to 3
   Grids Onto a 3/8 Inch High Polyurethane
   Foam Block Sitting in Chloroform in a
   Petri Dish.  The Surface of the Chloroform
   is About 1/8 Inch From the Top of the
   Polyurethane Block.

   Cut  a 1/8 Inch Diameter Disc (the Size
   of the Specimen Grid) From the Carbon-
   Coated Filter With a Sharp Specially-
  Made Boring Tool.

   With a Pair of Tweezers, Place the Carbon-
   Coated Filter Disc With Carbon Side Down
   Onto the Grid.
Metallurgical Lab.
Metallurgical Lab.

Metallurgical Lab.
Technician



Technician

Technician
Metallurgical Lab.
Metallurgical Lab.
Technician
Technician
                   Use thin  strip  (1/4 inch wide)
                   tape to hold  filter.
Pieces from 4 samples mounted
on one slide and a total of 12
pieces on 3 different slides can
be coated in one operation.  Ladd
Industries carbon appears to be
best A 1 x 4 ran rod is used.

Color development should be dark
yellow to yellow-brown.
                   The tool is  machined  from tool
                   steel and hardened to the level
                   of surgical  steel.
                   This is a tricky operation:   must
                   place one edge down first  and then
                   rapidly lay down the other.
                                                                                                                    (1 of 3)

-------
                                 Table D-4 -  Particulate Analysis by  Electron Microscopy - Sequence 8B
a
N]
                            Operation
                Sample Preparation  (Continued)

                   Cover the Petri  dish and Allow to Stand
                   Approximately  3  Hours.  Note:  See
                   Reference diagram below
                   Remove Grid with  Carbon Film From Bath
                   and Carbon Coat the Debris Side in the
                   Vacuum Evaporator.

                   Store on a Filter Paper in Another
                   Petri Dish.  They are now Ready for
                   Electron Microscopy.
  Location
Metallurgical Lab.
Metallurgical Lab.
Metallurgical Lab.
                      Responsibility
Technician
Technician
Technician
                                                    Remarks
                  The Nuclepore filter is
                  apparently dissolved by the
                  the chloroform by wick action
                  through the pores of the car-
                  bon replica.
                                                                               Nuclepore filter

                                                                               Debris

                                                                               Carbon Replica

                                                                               Copper Grid

                                                                                           - Cover

                                                                                           -Petri Dish

                                                                                           - Chloroform

                                                                                           Polyurethane
                                                                                                                               (2 of 3)

-------
t)
00
                                 Table  D-4 - Particulate Analysis by Electron Microscopy - Sequence 8B
                              Operation
              Sample Counting

                 Fill Out Count Sheet

                 Calibrate the Microscope.
                Place a Sample Grid in the Microscope
                and Check Several Grid Openings to
                Ensure that the Grid is Suitable for
                Counting.

                Set up EM at 22.000X for Fiber Identi-
                fication by Morphology and Electron
                Diffraction.    	

                Count and Record Fibers for Each of 20
                Fields in a 400 Mesh Specimen Grid.
                Use a Hand Counter or Other Method to
                Record the Number of Fields Counted.

                Count all Fibers Crossing the Limits
                of the Counting Field on Two Adjacent
                Sides (Top and Left).   Record the
                Counts in the Various size Ranges
                Given on the Count Sheet (Exhibit
                D-I).

             Electron and/or X-ray Diffraction

                Check Crystallinity of Several Particles
                and Fibers,  and/or Fields.
   Location
       D-212

Metallurgical Lab.



Metallurgical Lab.




Metallurgical Lab.



Metallurgical Lab.




Metallurgical Lab.
Metallurgical Lab.
                       Responsibility
Project Engineer

  Microscopist



  Microscopist




  Microscopist



  Microscopist




  Microscopist
  Microscopist
                                                    Remarks
Binocular magnification at
10X can be used for greater
magnification.
A field is defined as an area
within the square etched on the
grid.
Record typical diffraction patterns.
                                                                                                                                     (3  of  3)

-------
Table D-5 - Asbestos Emissions and Size Distribution - Sequence 9
Operation
Total the Number of Fibers in Each Size
Category
Calculate the Total Fiber Volume
Calculate the Total Fiber Weight.
Calculate the Total Fiber Concentration
Calculate and Plot the Asbestos Particle
Size Distribution
Location
D-212
D-212
D-212
D-212
D-212
Responsibility
Project Engineer
Project Engineer
Project Engineer
Project Engineer
Computer
Remarks






-------
                                 Table D—6 -  Noncondensable Gaseous  Emissions Processing  - Sequence 10A
V
K1
O
Operation
                 Fill Out Gas  Analysis  Sheet  (Exhibit
                 D-II) .

                 Check Gas Storage Box.

                 Start  Up Gas  Chromatograph With Porapak
                 Column  Installed.

                 Start Up Gas  Processing Equipment

                 Connect Noncondensable Gas Trap to Gas
                 Inlet Tap With Vacuum Tubing.  Pump
                 Out  Tubing.
                 Place Dry Ice Trap Around Primary Inlet
                 Trap.   Place  Liquid Nitrogen Around
                 Secondary Inlet Trap.
                 Maintain  Gas Storage Box at Dry Ice Tem-
                 perature.  Open Taps and Allow Nonabsorbed
                 Gases  to  Escape From All 3 Traps.

                 Isolate Condensable Gas Trap.
                Pump Out G.C. Sample U-Tube.  Close High
                Vacuum Tap to Isolate .Manifold.  Remove
                LN2 Trap.

                Remove DI in Gas Storage Box and Raise to
                Ambient.

                Begin Collection of Adsorbed Noncondensable
                Gases in Gas Burette With Toepler Pump.
                Complete Gas Measurement.  Select a Portion
                for Analysis by G.C.  Discard Remainder or
                Store a Portion in an Empty Gas Storage
                Volume.

                Collect Additional Fractions Until All
                Gases are Measured and Analyzed.
                                  Location
                                    D-212


                               Analytical Lab.

                               Analytical Lab.


                               Analytical Lab.

                               Analytical Lab.



                               Analytical Lab.



                               Analytical Lab.



                               Analytical Lab.


                               .Analytical Lab.



                               Analytical Lab.


                               Analytical Lab.



                               Analytical Lab.




                               Analytical Lab.
  Responsibility
 Project Engineer


Gas Chromatographer

Gas Chromatographer


Gas Chromatographer

Gas Chromatographer



Gas Chromatographer



Gas Chromatographer



Gas Chromatographer


Gas Chromatographer



Gas Chromatographer


Gas Chromatographer



Gas Chromatographer




Gas Chromatographer
                                                                                     Remarks
Record condition.

See conditions in Exhibit
D-III.
Insure good seal prior
to further processing.
To remove any possible
condensable.
To remove carrier air from
sample.  Check vacuum return
periodically.

To be analyzed later
separately.

Top-up DI trap.
If amount appears to be
large, close valves and
isolate a portion.

Record quantities and G.C.
results Exhibit D-III
for each fraction.

Record as  above.

-------
             Table D-7 —  Analysis  of  Noncondensable Gaseous Emissions  - Sequence 10B
              Operation
                                                  Location
                                                                        Responsibility
                                                                                                    Remarks
Insure G.C. Parameters are Properly Set for
Porapak Column.

Check Base-Line Stability of Thermal
Conductivity Detector.

Select a Portion of Gas Burette Sample
for G.C. Analysis.

Open Gas Burette 3-Way Tap and Push Gas
Sample Into Sample U-Tube.  Raise Mercury
to Tap of Gas Burette.

Close 3-Way Tap."

Turn G.C. Recorder On. Adjust Chart Paper
to Record Injection Time.  Record Sample
Identification on Chart.

Inject Sample.  Record Injection Time and
Attenuation.

Monitor G.C. Analysis.

Lower Mercury Level in Gas Burette. Keep
Mercury Seat Valve Open.

Open High Vacuum Tap to Diffusion Pump.

Open 3-Way Tap to Pump Out G.C. Sample
U-Tube.

Monitor G.C. Retention Times, Peak Heights
and Attenuation Settings.

Check Gas Burette Vacuum.  Close 3-Way Tap
to Isolate G.C. Sample U-Tube.  Prepare a
Calibration Sample for G.C. From a Gas
Storage Bulb.

Inject Calibration Sample and Record as
Above.

(Run Infrared Analysis).
Analytical Lab.


Analytical Lab.


Analytical Lab.


Analytical Lab.



Analytical Lab.

Analytical Lab.



Analytical Lab.


Analytical Lab.

Analytical Lab.


Analytical Lab.

Analytical Lab.


Analytical Lab.


Analytical Lab.




Analytical Lab.


Analytical Lab.
Gas Chromatographer


Gas Chromatographer


Gas Chromatographer


Gas Chromatographer



Gas Chromatographer

Gas Chromatographer



Gas Chromatographer


Gas Chromatographer

Gas Chromatographer


Gas Chromatographer

Gas Chromatographer


Gas Chromatographer


Gas Chromatographer




Gas Chromatographer


Gas Chromatographer
                                              See Exhibit  D-III
 Attenuation XI.
 Use 4.98  cc  volume  at  5  to
 15 cm pressure.

 Do not allow mercury into
 bore of top.
After  10 sec., return top
to normal He flow positions.
Use magnet to hold open.
Caution: Monitor pen to
insure full record.
(Inject sample into gas
cell through sample
U-tube.)

-------
KJ
                                  Table  D-8  - Condensable  Gaseous Emissions  Processing -  Sequence  11A
                                Operation
                                                                   Location
                         Responsibility
                                                                                                                     Remarks
                  Insure Condensable Gas Trap is Under Vacuum.

                  Place Dry-Ice Around First Distillation
                  Trap and LN2 Around Second Trap.

                  Distill Contents of Condensable Gas Trap
                  Through Traps in Gas Handling System.

                  After Distillation, Allow LN2 Trap to
                  Ambient Temperature and Determine Amount
                  and  Composition of Noncondensable Gases.

                  Replace Tubing at Gas Inlet With a
                  Specially Built, Weighed Glass Vessel.

                  Evacuate and Isolate the First Trap and
                  This  Vessel.  Heat Trap and Cool Vessel so
                  that  a Vacuum Distillation Transfers Con-
                  densable Gases to Vessel.

                  When  All Liquid is Transferred, Close
                  Stop-Cock and allow to come to Ambient

                  Weigh and Determine Weight of Condensable
                  Gases.

                  Analyze by Gas Chromatography.
Analytical Lab.

Analytical Lab.


Analytical Lab.


Analytical Lab.



Analytical Lab.


Analytical Lab.




Analytical Lab.


Analytical Lab.


Analytical Lab.
Gas Chromatographer

Gas Chromatographer


Gas Chromatographer


Gas Chromatographer



Gas Chromatographer


Gas Chromatographer




Gas Chromatographer


Gas Chromatographer


Gas Chromatographer
Clean vessel with solvent
and regrease stop-cock.

-------
                            Table D-9 - Analysis of Condensable Gaseous Emissions - Sequence 11B
Operation
Insure G.C. Parameters are Properly Set
for Silicone Gum Column.
Check Base-Line Stability of Flame loni-
zation Detector.
Turn G.C. Recorder On. Adjust Chart Paper
to Record Injection Time. Record Sample
Identification On Chart.
Inject 1.0 ul Sample. Record Injection
Time and Attenuation.
Monitor G.C. Analysis.
Run Calibration Blend.
(Run Infrared Analysis.)
Location
Analytical Lab.
Analytical Lab.
Analytical Lab.
Analytical Lab.
Analytical Lab.
Analytical Lab.
Analytical Lab.
Responsibility
Gas Chroma-tographer
Gas Chromatographer
Gas Chromatographer
Gas Chromatographer
Gas Chromatographer
Gas Chromatographer
Gas Chromatographer
Remarks
See Exhibit D-III
Attenuation XI Range 10.


Monitor temperature
p ro gr amming .
Periodically.
(Periodically. Blank out
solvent plus calibration.)
Co

-------
Table D-10 - Total Gaseous Emissions - Sequence 12
Operation
Total the Number of Moles of Each Noncon-
densable Gas Produced.
Relate the Number of Moles of Condensable
Gases Formed to the Internal Calibration
and to the Calibration Blend.
Calculate the Carbon Content in Grams.
Total the Carbon Content.


Location
Laboratory

Laboratory


Laboratory
Laboratory


Responsibility
Project Engineer

Project Engineer


Project Engineer
Project Engineer


Remarks






Can be related to weight
lost x organic fraction x
carbon fraction.

-------
                                     Exhibit D-I

                            MICROSCOPY COUNT SHEET
    Vehicle Test:
    Schedule:
    Collector:
    Sample:
    Date:
Total Sample Weight:
LTA Weights (I/F):
Count Weight:
Comments:
o
o
o
o
o
sf
     16
     29
     30
           0.03
              0.05
           0.05
              0.08
           0.03
              /
              0.25
           0.25
              /
              0.50
           0.50,
              1.0
              3.0
                EM Field Size:
                   3.0 x 3.0]]
                No. of Fields:
                                       FIBER LENGTH (u)
_mg
jng
 mg
    Date Counted:
    OM Field Size:
    No. of Fields:
                                             Microscopist:
                                                                                  D-15

-------
                     Exhibit D-II - Gaseous Emissions Data
Sample:   	            Sample Date:
Run No:   	            Analyst:
Location: 	            Analysis Date:
Box No:	
Comments:
Noncondensable Emissions:
         P =
         V =
         T =
         n =
        H2
        N2
        °2
        CO
       co2
      C2H6
Condensable Emissions:
     Sample Plus Tare:
                 Tare:
               Sample:
D-16

-------
                                           Exhibit D-III
INSTRUMENT SETTINGS:
  Column:


  Flow:
  Temperature Program:
  Detector Temperature:
ELUTION ORDER:
                                 ANALYSIS OF NONCONDENSABLE
                                     GASEOUS EMISSIONS
10' 1/8" O.D. Stainless Steel packed
80/100 mesh Porapak Q
40 cc/min He
-80°C to 160°C programmed at 10°C/min.
160°C (Dual Thermal Conductivity)
Hydrogen
Nitrogen
Oxygen
Carbon Monoxide
Methane
Carbon Dioxide
Ethane
Water
C3 to C^'s
                                                 ANALYSIS OF CONDENSABLE
                                                   GASEOUS EMISSIONS
6' 1/8" O.D. Stainless Steel packed
with 10% W-98 on 80/100 mesh
Chromosorb W
40 cc/min He
25°C to 260°C programmed at 6°C/min.
300°C (Dual Flame lonization)
C3 to 04*3
Benzene
Toluene
Xylenes
Phenols
Cresols
DM and TM Phenols
n-Ci6 solvent
n-C   calibration

-------
                              APPENDIX E

        ELECTRON MICROSCOPY ANALYSIS OF BRAKE EMISSION SAMPLES
E.I   SUMMARY

      The previously developed technique for preparing brake emission
debris for viewing with the electron microscope was found to be unsat-
isfactory for test car samples.  That procedure was developed with
standards and employee vehicle wear debris.  When applied to the test
vehicle brake emissions, excessive film breakage and instability occurred.
Consequently,  the technique was modified so that it was reasonably sure
that no further difficulties would be encountered with the remaining
samples to be analyzed.   Basically success was achieved with (1) use
of a finer copper grid,  (2) double carbon film, and (3) reduced debris
loading on the film.   The details of the procedure, as modified, are
given in Exhibit E-l.

E.2   PROBLEM

      The difficulty with the previously developed procedure was
manifested by the following:
      (1)  Fracture of the carbon film occurred during the
           cleaning operation employed to remove the filter.
           The fracture  was so severe that carbon film coverage
           of the copper grid varied from 0 to 10% of the area
           originally covered.
      (2)  The large wear debris particles were unstable under
           the electron  beam (expansion and contraction).
           This particle movement tore the film and released
           the wear debris so that analysis was impossible.
      (3)  The filter and carbon film appeared to shrink under
           the action of the cleaning solvent.  This raised
           the question  as to whether concentration of the wear
           debris was occurring because of the shrinkage and in
           this way creating a discrepancy between the real and
           observed number of particles per unit area.

E.3   PROBABLE CAUSES
      It  was  assumed  that the first two difficulties were created by
the large nonasbestos wear debris particles.  These particles appeared
larger than  those  previously found in wear debris samples from the
employee  vehicle drum surfaces.   The large particles apparently cause
film tears  because  they  created thin spots or openings in the carbon
film during evaporation  attributable to shadowing effects.  These weak
                                                                     E-l

-------
 spots in the film and the bulk of the particles then contributed to
 film tearing during the strains of the cleaning operation.  The particle
 instability under the electron beam could be attributed to heating and
 charging effects.  The third difficulty occurred because the filter
 shrank under the action of the solvent before dissolving.  Since the
 carbon film and filter were initially attached, the filter stressed the
 carbon film and also caused it to distort or crack.

 E.4   SOLUTION ATTEMPTED
       The following procedures or materials were tried in an attempt
 to eliminate the film breakage problem.
       (1)  A range of film thicknesses was investigated from
            thinner to thicker than that previously used.

       (2)  Silicon monoxide films were used in the hope that
            they would provide additional strength.

       (3)  Different films and film combinations were tried.
            These included chromium, platinum-carbon, chromium
            on carbon and collodion on carbon.

       (4)  Extreme care was exercised in laying the film on
            the grid prior to cleaning in order to ensure no
            handling breakage.
       (5)  The time to clean the filter from the film was
            shortened in an attempt to prevent breakage during
            cleaning.

       (6)  The cleaning solution was diluted or saturated in
            an attempt to reduce the severity of the cleaning
            operation.

       (7)  Carbon film was cleaned both while on a rough and
            on a smooth side of carbon grid.

       (8)  Vacuum drying of the film following cleaning was
            tried to remove all traces of residual solvent in
            case this was the cause of particle instability
            under the beam.

       (9)  A finer mesh grid (400 instead of 200) was tried
            to provide greater support for the carbon film.

      (10)  A second carbon film was vaporized over the wear
            debris and onto the original film following the
            cleaning operation.  This sandwiched the wear debris
            between two carbon films.  It was hoped that the
            additional film would provide additional strength
            and reduce particle instability.
E-2

-------
E.5   SUCCESSFUL APPROACHES

      Only the last three of the above mentioned techniques proved
significant in combating film breakage and instability: fine mesh grid,
double carbon film and lower debris loading on the film.  The 400 mesh
grid apparently provided greater support for the film and did reduce
breakage during cleaning.  The second carbon film applied after clean-
ing measurably strengthened the original film.  Although there still
appeared to be some particle instability under the beam the double
film was strong enough to resist tearing.

      The effect of the degree of loading on film integrity following
cleaning is shown in Figure E-l.  The debris was an air-borne sample
taken from the right rear brake following the baseline test.  All
samples were on a 400 mesh grid and received a double carbon film.
The debris loadings on the submitted filters were 1, 0.50, and 0.30 mg.
The last two show good film coverage while the 1 mg loading shows
extensive breakage.  Also the 1 mg loading showed more stability under
the beam than did the other two.  Therefore, even though the counting
time was increased because of the decreased loading, the filter loading
was reduced to less than 0.60 mg.

      Another consideration in selecting the debris loading for the
film was the possibility that the large particles would mask the
asbestos fibers.   Considering the extreme, if the debris were concen-
trated to the extent that particles covered the entire grid opening,
few fibers would be seen.  The debris distribution for several initial
filter loadings is shown in Figure E-2.
      The possibility of erroneous results due to film shrinkage with
attendant concentration of the debris was investigated.  It did not seem
reasonable that debris concentration would occur because the debris was
attached to the carbon film and the carbon film itself would not shrink
under the action of the solvent.  Since the periphery of the carbon
film was changing it was assumed that this could only occur by fracture
or distortion of the film.  Optical microscopy confirmed the assumptions.
The film did not undergo shrinkage, but rather accomplished the dimen-
sional change by forming folds as shown in Figure E-3.  These folds
were confined mainly to the periphery and would not pose any difficulty
to the measurement as long as the folded area was avoided.  In other
films the folds were not confined entirely to the periphery, however,
these areas could easily be avoided during the counting as they were
readily detectable on viewing with the electron microscope.  Therefore,
the film folding under the action of the solvent posed no serious diffi-
culties in the analysis.
                                                                     E-3

-------
Figure E-l - Photomicrographs of Carbon Films on 400-Mesh Grid 50X
             [Films were made from filters with original debris loading
             of 0.3 (upper), 0.5 (center) and 1 (lower) mg.  Debris was
             airborne collection from A.B. Baseline schedule of vehicle
             test for right rear drum brake]
E-4

-------
Figure E-2 - Electron Micrographs of Debris Distribution on Carbon
             Films Made from Initial Filter Loadings of 0.3 (upper),
             0.5 (center) and 1 (lower) mg.  (Debris was airborne
             collection from Baseline test) 6000X
                                                                  E-5

-------
         Oil*:
Figure E-3 - Photomicrograph of Carbon Film on 400-Mesh Grid Following
             Cleaning -Operation.  SOX (Shrinkage was due  to film  folds
             near periphery of film.  Film was made from  filter with
             0.5 mg debris loading.)
E.6   CONCLUSIONS
      1.   The modified technique for preparing electron microscopy
           samples should provide a trouble-free method for analyzing
           all samples required for the program.

      2.   Loading of the filter was limited to less than 0.6 mg.
           This was required to prevent film breakage and, in addition,
           there was less chance of the large particles masking the
           asbestos fibers.
      3.   Film folding during cleaning did not introduce error into
           the analysis.
E-6

-------
                              EXHIBIT  E-I
              PROCEDURE FOR ELECTRON MICROSCOPY ANALYSIS
                       OF BRAKE  EMISSION SAMPLES
 1.  Receive  and  log  in sample.

 2.  Cut  out  1/2-inch filter circle with special cutter.

 3.  Mount  filter circle (debris side up) on glass slide  with tape.
 4.  Vacuum evaporate carbon film on filter circle (4 mm  length of
    carbon rod;  1 mm in diameter).

 5.  Remove from  evaporator and  cut out four 1/8-inch circles with
    special  cutter.
 6.  Prepare  cleaning bath to remove filter from carbon film by the
    following  steps.   Put polyurethane foam block in a petri dish
    and  fill with chloroform to about 1/8-inch below the foam surface.
    Put  400  mesh copper grids on the top surface of the  foam.
 7.  Place  1/8-inch carbon-coated circles on grids in the chloroform
    bath with  carbon side down.
 8.  Let  sample clean in bath at least 3 hours.  Bath is  covered during
    cleaning to  prevent contamination.
 9.  Remove the carbon film on the grid from bath and carbon coat the
    debris side  in the vacuum evaporator.
10.  Remove from  evaporator and  view in transmission electron microscope.
                                                                    E-7

-------
                                            APPENDIX  F

                          COMPUTER  PROGRAM FOR COMPUTATION OF
                                    ASBESTOS  CONTENT  USING
                             ANALYTICAL MICROSCOPY  TECHNIQUES
FORTRAN  IV G LEVEL  70
                                      MAIN
                                                        DATE    710?4
                                                                              15/1=1/51
                                                                                                  PAf.F 0001
0001
0002
0003
0004
0005
0006
0007
0008
0009
0010
0011
0012
0013
0014
0015
0016
0017
0018
0019
0020
°021
0022
            C**** ************************ **************** ***********************»****,*,. ».,
            C     IN TWO DIMENSIONAL ARRAYS,  IND^X  I CORRESPONDS TO »OWS  11   14,
            C         15*25, 16*26, 27 -31 ON MICROSCOPY COUNT  SHFFT  \Hn  1N1FX J
            C         CORRESPONDS Tn fOUI"NS  1   '8  ON  MICROSCOPY COUNT SHFFT.
            C* ******************************************************************************
                  DIMENSION BOX ( 49 I , VOL ( 1 2 , 8) , I VOL ( 12 , P I , FCTP ( 2 I , VPLT ( 49 )
                 1  , INM( 8I.XC1LI12.RI ,
                 1   IVH<5»,ISCH(20I,ICOL(20I,ISAMP(20I,IDATF(10I,TOT(2I
            C**** ************ ******************************** *******************************
            C     ARRAY XOL CONTAINS VOLUME * 10**17.
            C**** ***************************************************************************
                  DATA XOL/.077F-3, .2E-3, . 53E-3 , 9*0 .0,
                 2    .192E-3,.5E-3,l.31E-T,10.15E-3,fl*0.0,
                 3    .51E-3, 1. 34'r-3,3.?)f-3,27.1F-3,12?.?-3,.<)82,6*0.0,
                 4    1.66E-3,4.25E-3,11.3E-3,!)8.0E-3,401.E-3,:i.l9,12.fl,'<3.2,63.6,
                 4    3*0.0,
                 5    3.83E-3.10.E-3,26.3E-3,203.E-3,floo.E-3,7. 1, 29.» , 7f,. 7, 1 47. ,
                 5    241. .436. ,0. ,
                 6    7,77E-3,20.E-3,52.f'E-3,406.E-3, 17 80. E-3, 13. 5, 53. 8, 141. ,270.,
                 6    433.,805.,1.6PE3.
                 7    4*0. 0. 2960. F- 3, 23. 3. 9 3., 243., 466. , 765 . , 13RO. , 2 . 89E3 ,
                 8    4*0. 0,4 740. =-3,39.3,1 57., 40 9. ,794.,1290.,2.33E3,4.69E3/
            C**** it*************************************************************************
            C     FCTRIll MULTIPLIES POWS  11-16.  FCTRI2I MULTIPLIES  ROWS 25-31.
            C****** **#***#****#***#**#####***###*#**#*$$##*#*#****#***#*#*###?* #*##*********
                  DATA FCTR/110.E6..12784F6/
                  DO 190 1=1.12
                  PRINT 999.1 ,( XOL ( I. J) ,J=1 .81
              999 FORMAT! I5.8E14.5)
              190 CONTINUE
                  STEP=1. 0/6.0
            C**** ******** *******************************************************************
            C     COMPUTE ARRAY BOX PO"  LOG-LOG  PLOT.  BOX =  10**-!'.  TO 10**-fl IN
            C         .STEPS OF  10**l/6.
            C**** ***************************************************************************
                  DO 10 1=1,49
                  BOXU I = STEP*( 1-11-4.0-13.0
               10 CONTINUE
            C**** ***************************************************************************
            C     COMPUTE VOL(I.J)   THE LOG OF   XOLH.J) AND MULTIPLY XOL (I.JI BY
            C         10**-12
            C**** ***************************************************************************
                  DO 20 1=1,12
                  00 20 J=l.fl
                  IVOL(I,J)=0
                  VOL(I,J)=0.0
                  IF( XOL( I,J) .EO.O.  IGO TP 20
                  VOL(I.J)=ALOG10(XOL(I.J) 1-12.0
                  XOL(I.J)=XOL( I ,JI*1.E-12
            c**** ***************************************************************************
            C     COMPARE VOL(I.J) TO ARRAY BOX.   ASSIGN NUMBER OF CLOSEST BOX TO
            C         IVOLd.JI.
            c**** ***************************************************************************
                  00 30 K=l,49
                  IFIVOLI I.JI .LE.BOX(KI IGO TO 40
               30 CONTINUE
                  K=49
               40 IVOL(I.J)=K
                                                                                                F-l

-------
FORTRAN IV C, LEVEL  20
                                       MAIN
                                                          OATF  =  -73024
                                                                               15/19/51
                                                                                                    PAGE 0002
 002*
 0025
 0026
 0027
 0028
 0029
 0030
 0031

 0032
 0033
 0034
 0035
 0036
 0037
 0038
 0039
 0040
 0041
 0042
 0043
 0044
 0045
 0046
 0047
 0048
 0049
 0050
 0051
 0052
 0053
 0054
 0055
 0056
 0057
 0058
 0059
 0060
 0061
 0062
 0063
 0064
 0065

 0066
   20 CONTINUE
      DO 50 1=1.49
      BOXU )=10.0**BOX1 I I
   50 CONTINUE
      00 191 1=1,12
      PRINT 999,1 ,( VOLd.JI ,J=1.8)
  191 CONTINUF
C
C     START DOING STUFF
C
C**** ***************************************************************************
C     READ HEADING CARD.
C*******************************************************************************
  100 READ (5,900,END=500> 101.(IVH(I I,1=1,5),(ISCH(J),J=1.20).
     1  (ICOL(KI,K=l,20t,(ISAMP(L).L=1.20>,(I HATE(M),M=1,101
  900 FORMATII4.1X.75A1)
      READ (5,9011 ID.TOTWT.XI,XF,XCNT
  901 FORMAT!I4.6X.4E10.0)
      IF( ID.NE.IDDGO TO  501
      TOTWT=TOTWT*.001
      XI=XI*.001
      XF=XF*.001
      XCNT=XCNT*.OOl
      DO 200 1=1,49
      VPLTII 1=0.0
  200 CONTINUE
C*******************************************************************************
C     TOT(l)   SUM OF ROWS 11-16.  TOTI2I =  SUM OF  ROWS  25-31.
c*******************************************************************************
      TOT(1)«0.0
      TOT(2>=0.0
      TOTAL=0.0
  110 READ (5,920) ID,I.J.(INM(K),K=l,8),ITOT
      IF(ID.NE.I011GO TO  501
  920 FORMAT!14,211.4X,BI3,6X,15)
      IF(I.EQ.2IJ=J+l
      IF(I.E0.3)J=J+11
      IFd.EO. 3)1=2
      DO 120 K=1.8
      TOT(I) = TOTdl+2.56*XOLtJ,KI*lNM(KI*FCTR(I)/I TOT
      IF(IVOL(J,K).EO.O)GO TO 120
      VPLT( IVOLI J,K)) = VPLT(IVOL(J.KI) + INM(K)*FCTR(I l/ITflT
  120 CONTINUF
C*******************************************************************************
C     TEST FOR LAST DATA  CARD.
C*******************************************************************************
      IFd.EO.2.AND.J.E0.12IGO TO  130
      on TO no
  130 CONTINUE
      TOTAL=TOT!l)+TOT<2)
      PCT=TOTAL*XF*100.0/(XCNT*XII
      PRINT 911
  911 FORMAT!'I1,45X,'**** ASBESTOS ANALYTICAL  RESULTS  ****•)
      PRINT 912.TOT!1 I,TOT(2)
  912 FORMAT! '0',105X,'FM SUB TOTAL = •,El 1.4,/105X,•OM SUB TOTAL =•,
      1   Ell.4)
      PRINT 910,(IVH! I I,1 = 1,5),(I DATE(J),J-1,10),X I.TOTAL,
      1   (ISCH(K),K=1,20I,I01,XF,XCNT.
F-2

-------
                        FORTRAN IV G LEVFL   20
                                                                MAIN
                                                                                   DATE  =  73024
                                                                                                        15/19/51
                                                                                                                              PAGE 0003
                         0067
                        0068
                        0069
                        0070
                        0071
                        0072
                        0073
                        0074
                1  (ICOL(L),L=1,20) i
                1   ,M=1,20>,PCT
             910 FORMAT('OVEHICLE  TEST:  • , 5A1, 30X, 'D ATE :  • , 10A 1, 13X, ' LTA ( I ) = • . f I 1.4
                1.16X,'TOTAL =',E11.4,/    5X,'SCHEDULE:  •.ZOAlilSX.1  NO.:  '.I5.18X,
                2'LTAtF)=',E11.4,  9X,'COUNT WEIGHT =',E11.4,/'  ',3X,'COLLECTOR: ',
                320A1,/'  ',6X,'SAMPLE:  ',20A1,SOX,'ASBESTOS  PERCENT =•,F7.3,•*',/>
                 CALL  LGPLT(BOX,VPLT,49)
                 GO TO 100
             500 STOP  1
             950 FORMAT!'1  CARDS  OUT  OF  ORDER ON  RUN NO.',15)
             501 PRINT 950,101
                 STOP  999
                 END
                        FORTRAN IV G LFV^L   20
                                                                MAIN
                                                                                        = 73024
                                                                                                         15/19/51
                                                                                                                              PAGE 0004
                                                      SUBPROGRAMS CALLED
                       SYMBOL    LOCATION       SYMBOL    LOCATION       SYMBOL     LOCATION      SYMBOL    LOCATION
                       IBCOM*        14C         FRXPR*       150         LGPLT        154        ALOG10        158
                                                                                                SYMBOL
                                                                                                          LOCATION
                                                      SCALAR MAP
                       SYMBOL    LOCATION       SYMBOL    LOCATION
                       I              174         J             178
                       L              188         M             18C
                       XF            19C         XCNT         1AO
                                              SYMBOL     LOCATION      SYMBOL    LOCATION       SYMBOL     LOCATION
                                              STPP          17C         K            180         101           184
                                              ID            190         TOTWT        194         XI            198
                                              TOTAL         1A4         ITOT         1A8         PCT           1AC
                       SYMBOL    LOCATION
                       BOX           1BO
                       [NM           640
                       I SAMP         894
                            ARRAY MAP
                      SYMBOL    LOCATION      SYMBOL     LOCATION      SYMROL    LOCATION       SYMBOL     LOCATION
                      VOL          274        IVOL          3F4         FCTR         574         VPLT          57C
                      XOL          660        IVH           7EO         ISCH         7F4         ICOL          844
                      IOATE        HF4        TOT           90C
                                                      FORMAT STATEMENT  MAP
                       SYMBOL    LOCATION       SYMBOL    LOCATION       SYMBOL     LOCATION
                          999        914            900       91D            901        927
                          912        972            910       9A2            950        A6D
                                                                       SYMBOL
                                                                          920
LOCATION
   932
SYMBOL
   911
LOCATION
   944
to
*OPTIONS  IN  EFFECT*   ID,EBCD1C.SOURCE,NOLIST.DECK.NOLOAD,MAP
*OPTIONS  IN  EFFECT*   NAME = MAIN    , LINECNT =        60
*STATISTICS*    SOURCE  STATEMENTS =       74,PROGRAM  SIZE  =
*STATISTICS*  NO  DIAGNOSTICS GENERATED

-------
                               APPENDIX G

                       VEHICLE TEST DATA REPORTS
      Because of the large number of test reports for different phases
of the vehicle tests and subsequent collection of brake emissions,  the
individual data sheets were assembled into a separate volume for each
vehicle test.  The original test data sheets were retained by the
Principal Investigator at Bendix Research Laboratories.

      The volume for each vehicle test contains seven major sections,
one for each test schedule; and each section is broken down further
into three secondary sections for the vehicle operation results, the
brake emissions data sheets, and the,analytical results:
      Vehicle operation data reports:
      •  Figure G-l is the Vehicle Log Sheet which remained in the
         vehicle to record the overall vehicle operation throughout
         the test schedule.

      •  Figure G-2 is the Burnish report.
      •  Figure G-3 is the Detroit Traffic data sheet used during the
         Baseline and Detroit Traffic schedules.

      •  Figure G-4 is the 10-Stop Fade data sheet.
      •  Figure G-5 is the 15-Stop Fade data sheet.

      •  Figure G-6 is the Recovery data sheet used in conjunction  with
         the 10- and 15-Stop Fade data sheets during the Fade schedules.

      •  Figure G-7 is the Reburnish data sheet used in the 10- and
         15-Stop Fade schedules.

      Brake Emissions data sheets:
      •  Figures G-8 and G-9 are the Wear Sheet-Front Axle and Wear
         Sheet-Rear Axle used to record both weight and thickness losses
         of all friction materials on the vehicle.
      •  Figures G-10 and G-ll are the Collection of Brake Emissions
         (Right Side) and Collection of Brake Emissions (Left/Control
         Side) which were used to record and calculate the brake wear
         debris collected in the sump, on the surfaces, and the airborne
         samples.
      •  Figure G-12 is the Test Summary Sheet used to summarize the
         wear data and to check out the material balances.
                                                                     G-l

-------
Analytical Results:
•  Figure 8-13 is the Microscopy Count Sheet onto which each fiber
   found by microscopy was classified according to its dimensions.

•  Figure 8-16 is the Computer Printout which gave the asbestos
   percent and the size distribution.

•  Figure G-13 is the Asbestos Emission Summary Sheet used to
   summarize each test schedule.

-------
                       \/£tfiCLE   LOG,
7e.st A/o.
Dates:   Start:
Test Sefft/ent
DfiT£







TttTALS
4MB.
CF)








?e:

M,™








ODOfn&TER
START








F/HNISH








Tom.









STOPS
flfPL.








COMMTC








Fini&h :

COMMENTS








                      Figure G-l - Vehicle Log Sheet

-------
                                                  Test No.,
Burnish (Brake Performance  Test Weight);




Odometer	 Date	
Temp,
200 Stops, 40 MPH, 12 FPSPS in Highest Gear, 250° IBT or 1 Mile Maximum -
40 MPH Cooling Speed, 80% Burnish
Stop
1
20
40
60
80
100
120
140
160
180
200
Initial Temperatures °F
L.F.











R.F.











L.R.











R.R.











Max.
L.P. psi











Max.
P.F. Ib.











P.T.
in.











Comments











Comments
                         Figure G-2 - Burnish Report
  G-4

-------
        DETROIT  CITY TRAFFIC TEST
START ODOM. 	
CAR NO.
START **
MICH. & 3RD. **
ADAMS & WOOD.
ADAMS & WOOD.
12 MILE **
ADAMS & WOOD.
ADAMS & WOOD.
ADAMS & WOOD.
12 MILE **
ADAMS & WOOD.
ADAMS & WOOD.
ADAMS & WOOD.
12 MILE **
ADAMS & WOOD.
ADAMS & WOOD.
ADAMS & WOOD.
12 MILE **
ADAMS & WOOD.
ADAMS & WOOD.
ADAMS & WOOD.
12 MILE **
ADAMS & WOOD.
ADAMS & WOOD.
END **
END ODOM.

TIME
























AMB.

























L.F.
























TEST NO
R.F.
























L.R.
























•

R.R.
























DATE

COMMENTS
























Figure G-3 - Detroit Traffic Data Sheet
                                                   G-5

-------
                                                   Test No..
First Baseline:  (Brake Performance Test Weight)


Odometer	Date _	
.Temp..
3 Stops, 30 MPH, 10 FPSPS in Highest Gear, 140°-150° IBT Each Stop
Stop
1
2
3
Initial Temperatures °F
L.F.



R.F.



L.R.



R.R.



L.P.*PSI
Init.



Sust.



Fin.



Max.
P.F.
Ib.



P.T.
in.



Comments



 First Fade:   Odometer .
                                  .Date.
  .Temp.
                                                                       . Wind .
10 Stops, 60 MPH, 15 FPSPS in Highest Gear, 0.4 Mile Interval, 140°-150° IBT For Stop I
Req't.: 200# Maximum P.E. First Four Stops
Stop
1
2
3
4
5
6
7
8
9
10
Initial Temperatures °F**
L.F.










R.F.










L.R.










R.R.










L.P.*PSI
Init.










Sust.










Fin.










P.F. Ib.
Init.










Sust.










Fin.










P.T.
in.










Comments










  Total Elapsed Time .
                                .Sec.
   Must include maximum line pressure.
   *
   On cooling cycle.
                        Figure G-4 -  10-Stop  Fade Data Sheet
 G-6

-------
                                                   Test No..
First Baseline:   (Brake Performance Test Weight)

Odometer	Date	
                                                  . Temp..
3 Stops, 30 MPH, 10 FPSPS in Gear, 140°-150° IBT Each Stop
Stop
1
2
3
Initial Temperatures °F
L.F.



R.F.



L.R.



R.R.



L.P.*PSI
Inlt.



Sust.



Fin.



Max.
P.F.
Ib.



P.T.
in.



Comments



  First Fade:  Odometer.
                                  .Date.
                                                    _Temp..
                                                                       .Wind.
15 Stops, 60 MPH, 15 FPSPS in Gear, 0.4 Mile Interval, 140°-150° IBT For First Stop
Req't.: 200# Maximum P.E. For First Eight Stops
Stop
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Initial Temperatures °F
L.F.















R.F.















L.R.















R.R.















L.P.*PSI
Init.















Sust.















Fin.















P.F. Ib
Init.















Sust.















Fin.















P.T.
in.















Comments















 Total Elapsed Time              Sec.

 *
  Must include maximum line pressure.
                        Figure G-5 - 15-Stop Fade Data Sheet
                                                                                       G-7

-------
                                                               Test  No..
Recovery -  One Mile After Last Fade Stop, at 40 MPH Cooling Speed
12 Stops, 30 MPH, 10 FPSPS in Highest Gear, or Max. Decel.
for 200 Ib. PF if 10 FPSPS Cannot Be Obtained, One Mile Interval
Req't.: 5 FPSPS Minimum for 2009 P.E. for First 5 Stops,
150# Maximum P.E. for Stop #6
Stop
1
2
3
4
5
6
7
8
9
10
11
12
Initial Temperatures °F
L.F.












R.F.












L.R.












R.R.












L.P.*PSI
Init.












Sust.












Fin.












P.F. Ib.
Init.












Sust.












Fin.












P.T.
in.












Comments












Driver .
                                              . Observer.
(1)  If warning light is activated, which M'cyl. piston bottomed  out?  Front D  Rear D
(2)  Center differential valve piston.
(3)  Check front/rear pressure differential:
        Front  line pressure	PSI ^
        Rear line pressure	PSI  f   Read simultaneously at  approx. 1000 PSI
                          Figure G-6 -  Recovery Data  Sheet
G-8

-------
Reburnish (Brake Performance Test Weight);




Odometer	 Date	
,Temp..
35 Stops, 40 MPH, 12 FPSPS, 250° IBT of One Mile Maximum in Gear
Stop
1
10
20
25
35
Initial -Temperatures °F
L.F.





R.F.





L.R.





R.R.





Max.
L,P. psi





Max.
P.F, Ib.





P.T.
in.





Comments





                    Figure  G-7  - Reburnish Data Sheet
                                                                     G-9

-------
Vehicle Test No.




Test Sequence:_
                           WEAR SHEET.
.AXLE
MAKE OF CAR:




LINING:	
                                            .MODEL:.
COMMENTS:.
PTHHT

Date




Mileage




RTCTIT

Date




Mileage




T.F.FT

Date




Mileage




T.KT7T

Date




Mileage





Total
Stops




1




2




3




4




5




6









Weight Loss


Total
Stops




1




2




3




4




5




6




7




Weight Loss


Total
Stops




1




2




3




4




5




6









Weight Loss


Total
Stops




1




2




3




4




5




6




7




Weight Loss

                    . Figure G-8  - Wear Sheet -  Front Axle
  G-10

-------
Vehicle Test No..




Test Sequence:—
                       WEAR SHEET.
   .AXLE
MAKE OF CAR:,




LINING:	
.MODEL:
COMMENTS:.
Uir.WT BRAI

Date




Mileage




HTRHT RRA1

Date




Mileage




T.F.TT RRA1

Date




Mileage




LKFT RRAJ

Date




Mileage




CE (PRI. OR FORWARD)
Total
Stops




1




2




3




4




5




6




Weight Loss

CE (SEC. OR REVERSE)
Total
Stops




1




2




3




4




5




6




7




8




Weight Loss

CE (PRI. OR FORWARD)
Total
Stops




1




2




3




4




5




6




Weight Loss

CE (SEC. OR REVERSE)
Total
Stops




1




2




3




4




5




6




7




8




Weight Loss

                      Figure  G-9 - Wear Sheet - Rear Axle
                                                                              G-ll

-------
                                OF
   Test S&fu&>ee:
                                                       TestVat&s
                                                              Finish :
            FRONT  BtflKE
•SuMP SAMPLE'.  S,lter*4e.tirir.
 • Cafifer fl'cttn        /,#«t:
 -frVtttlil**

StfRFflCBS Sfi0Pl£ •• Sitter iJetns:
         tirtor       -filter:
            debris
        ^^^alohf-0*.
        tgtal tn OZu.
      1,131 m-filters:
                        %m
                                                  TOTAL S/)ffif/.e:
                                               !	> SUMP:
                                               \   i	> SURFACES:
                                                    r	>
                                                       COMMEMTS:
     RIGHT
              0/eAKE
     6i/Mp  SAMPLE:
      •]tletf-7raeK
      •dfv'ft //«/«s
      >r»Kg. P*t->
                    2 fitters;_
                     -t.i«l:
                -86%falui-n:_
                 2.0%/Sdtnifj;


                     filter:
              SAMPLE:
      •fitter + debris:
            -Pilier;
        TtiaL on S.o/n:
         fob/on M«:
      •iiiaL on •
     Cwrtded Suuf Samfle

              Previtus test • _
r _„„.
      i
|«n   j  TOTAL
                                               L-

                                               r"
                                                  i	=
                   Sump:
               ->•  SuRFRces:
                                                CoMMEttre:
                                                                                r
          Figure G-10 -  Collection  of Brake  Emissions  (Right Side)
G-12

-------
                                  Emission
Vehicle

Jest Saau.enc.e:
  i£Fr
  SUMP SAMPLE:  filter+ctabris:


  •Caliper fist'*          -filter.
         SAMPLE:' /i Her 4 debris:
     TOTAL SAMPLE:

     i	*• Sump

        --> St/erflces:
  LEFT  DRUM  BRRKE
    'SAMPLE'  -fik





•foot Ab/ss





               2.0%r*tun:




            •:-filter debris;
  •Drum




  COMMENTS:
CorreeleJ Sutup Sample
                                             i
                                             i     i	<	>
                                             i     i
                                        	i     i
                                     r
   foTfiL.
                                          i ------ >  SUMP •
                                               r
                           CL u TCH
                             •ttdat. an o.l'-


                                 filters.
        Figure  G-ll - Collection of Brake Emissions (Left Side)
                                                                          G-13

-------
                 TEST
   \Je,hicl&
            Stops'
Tf si Dates :  Start;
           F/his A
FROHT 2>/sc BtfflfeS •
Temperature fonfte f°f) '
S0inples Col teemed (artfij '
Sump •
Surfaces:
fl Id Is owe '•
ToTaL •
L'hinq UJear- \ */o
° TotaL
ffecovert °/o]
/?EAfi BUM BRAKES'
Tern fie ntvre K^nae (°p}
Samples Coll&c.'f'e.J (^ms-):
S i/i- fa ties :
Airborne:
TohL-
Lihin* Wear: P/<$
Toial
(.RetoverVfi
CLUTCH-.
Sample C°l/e
-------
                                      St/MMflW  SttEST.
 Vehicle, Test No..
 Test  Schedule :
     :  Debris data are repotted as
       Debris  Qenera+ed per- step)
                                              FIGHT
 CLUTCH
                                U
LEFT
                                                  D&bns:
                                                  Asbestos:
                                                  Debris :
  Debris :
  flsbestos;
                                        [\U
                                             Pl&UT
SUMP :
  Debt-is :
  ft s best**'.

SURFACES;
                                                  Asbestos:
                                                 flsbestor:
           Figure G-13 - Asbestos Emissions Summary Sheet
                                                              G-15

-------
                              APPENDIX H

                ASBESTOS  EMISSIONS ANALYSIS REPORTS
                FROM BATTELLE COLUMBUS LABORATORIES AND
           JOHNS-MANVILLE RESEARCH AND ENGINEERING CENTER


      The following information has been excerpted from the final summary
report "Asbestos Emissions  Analysis" by Battelle Columbus Laboratories
(C.  W. Melton and W. M. Henry) to the Environmental Protection Agency
(Contract No. 68-01-0416).  Dr. Joseph H. Somers was the Project Techni-
cal  Officer who supplied this information to Bendix Research Laboratories.

      The objective of the project was to analyze 24 clutch and brake
lining emissions for asbestos content.  The samples were generated, col-
lected, and submitted for analysis by the Bendix Research Laboratories.
      The analytical method used for asbestos in brake and clutch lining
emissions was a modification of one developed for the analysis of asbes-
tos  in collections of airborne particulate.  In general, results indica-
ted  that sump samples contained, by far, more asbestos than airborne or
surface samples.

Experimental  Procedure and Calculations;
      The analytical procedure employed was as follows:

(1)    An aliquot of the brake or clutch debris was weighed.
(2)    The aliquot was put into a centrifuge tube and was low-temperature
      ashed for three days.
(3)    The ash residue was suspended in 10 ml of an aqueous solution to
      which 3 drops of 1.0 percent Aerosol OT was added and then was
      treated ultrasonically to separate the asbestos fibers into colloi-
      dal fibrils.
(4)    The extraneous material was separated by centrifugation from the
      asbestos which remained in colloidal suspension in the supernatant
      liquid.
(5)    The supernatant liquid was filtered through a Millipore filter
      (HAWP 025, HA 0.45 y, 25 mm) to deposit the asbestos fibrils uni-
      formly  over the surface of the filter.
(6)    A carbon film was vapor-deposited over the asbestos fibrils on
      the filter and a 3-mm x 3-mm square was cut from the resulting
      carbon-coated specimen.
(7)    The filter was dissolved in acetone to leave the carbon film bear-
      ing the asbestos fibrils.
(8)    The carbon film was picked up on a 200-mesh electron microscope
      specimen support grid.
                                                                    H-l

-------
(9)     The support  grid and carbon film were loaded into the transmis-
       sion electron microscope and the fibrils within several (usually
       ten) grid openings  were counted and the results recorded as num-
       ber of fibrils per  grid opening.
(10)    The number of fibrils per grid opening was  translated into micro-
       grams of  asbestos in the aliquot taken by using a standard curve
       which was generated from known standard samples.
(11)    Percentage asbestos in the sample was calculated by dividing the
       weight of the detected asbestos by  the weight of the aliquot.
H-2

-------
Experimental Results

     Results of the analyses of the 24 samples submitted by Bendix are
as follows:
      BATTELLE
     SAMPLE NO.

     29897-1-1
     29897-1-2
     29897-1-3
      29897-1-4
     29897-1-5
      29897-1-6
      29897-8-1
      29897-8-2
BENDIX SAMPLE DESCRIPTION

Vehicle Test 1
Detroit Traffic Schedule
Right Front Brake
Airborne Sample

Vehicle Test 1
Detroit Traffic Schedule
Right Rear Brake
Airborne Sample

Vehicle Test 1
Detroit Traffic Schedule
Right Front Brake
Sump Sample

Vehicle Test 1
Detroit Traffic Schedule
Clutch
Airborne Sample

Vehicle Test 1
Detroit Traffic Schedule
Right Rear Brake
Surfaces Sample

Vehicle Test 1
Detroit Traffic Schedule
Right Rear Brake
Sump Sample

Vehicle Test 1
10-Stop Fade
Right Front Brake
Airborne Sample

Vehicle Test 1
10-Stop Fade
Right Front Brake
Sump Sample
PERCENT ASBESTOS
   IN SAMPLE
                                                                0.00055
                                                                0.00057
                                                                0.207
                                                                0.0068
                                                                0.0061
                                                                0.025
                                                                 0.031
                                                                 1.22
                                                                       H-3

-------
    BATTELLE
   SAMPLE NO.

   29897-8-3
   29897-8-4
   29897-8-5
   29897-8-6
   29897-8-7
   29897-8-8
   29897-14-1
   29897-14-2
   29897-14-3
BENDIX SAMPLE DESCRIPTION

Vehicle Test 1
10-Stop Fade
Right Rear Brake
Airborne Sample

Vehicle Test 1
10-Stop Fade
Right Rear Brake
Sump Sample

Vehicle Test 2
Burnish Schedule
Right Front Brake
Sump Sample

Vehicle Test 2
Burnish Schedule
Right Rear Brake
Sump Sample

Vehicle Test 2
Burnish Schedule
Right Front Brake
Airborne Sample

Vehicle Test 2
Burnish Schedule
Right Rear Brake
Surfaces Sample

Vehicle Test 1
Detroit Traffic Schedule
Right Front Brake
Surfaces Sample

Vehicle Test 2
Detroit Traffic Schedule
Right Front Brake
Airborne Sample

Vehicle Test 2
Detroit Traffic Schedule
Right Front Brake
Sump Sample
PERCENT ASBESTOS
   IN SAMPLE
                                                              0.0074
                                                              0.216
                                                              0.275
                                                              0.103
                                                              0.100
                                                              0.376
                                                              0.011
                                                              0.0057
                                                              0.62
H-4

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 BATTELLE
SAMPLE NO.

29897-14-4
29897-14-5
29897-14-6
 29897-14-7
 29897-14-8
 29897-14-9
 29897-14-10
BENDIX SAMPLE DESCRIPTION

Vehicle Test 2
Detroit Traffic Schedule
Right Rear Brake
Airborne Sample

Vfehicle Test 2
Detroit Traffic Schedule
Right Rear Brake
Sump Surface

Vehicle Test 2
Detroit Traffic Schedule
Right Rear Brake
Surfaces Sample

Vehicle Test 3
Detroit Traffic Schedule
Right Front Brake
Airborne Sample

Vehicle Test 3
Detroit Traffic Schedule
Right Front Brake
Sump Sample

Vehicle Test 3
Detroit Traffic Schedule
Right Rear Brake
Airborne Sample

Vehicle Test 3
Detroit Traffic Schedule
Right Rear Brake
Sump  Sample
PERCENT ASBESTOS
   IN SAMPLE
                                                           0.015
                                                           0.057
                                                           0.061
                                                           0.016
                                                           0.135
                                                           0.044
                                                            0.0104
                                                                  H-5

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 jonns-Manvine

 Research & Engineering Center

 P. O. Box 159
 Manville, N. J. 08835
 (201) 722-9000

 September 6,  1972
 Dr.  M.  G.  Jacko
 Materials  and Processes Department
 Bendix  Research Laboratories
 Southfield,  MI   48075

 Dear Dr. Jacko:

 We have finally completed the analysis of the brake  lining
 wear debris  you sent to us.  These samples were described
 as follows in your letter to Dr. Speil of July 5, 1972.

 Sample  No. 1 - Vehicle Test 1
 J-M  No. 4123-58-1  Detroit Traffic Schedule
                    Right Front Brake
                    Surfaces Sample

 Sample  No. 2 - Vehicle Test 1
 J-M  No. 4123-58-2  Detroit Traffic Schedule
                    Right Rear Brake
                    Surfaces Sample

 Sample  No. 3 - Vehicle Test 1
 J-M  No. 4123-58-3  Detroit Traffic Schedule
                    Right Rear Brake
                    Airborne Sample

 The  fiber-  content of the samples and the weight loss on
 ignition are given below.   The fiber content was determined
 by the  rub-out procedure which I believe we explained to you
 at the  time  of your visit to our laboratory.

                                         Mo. 1-  No.  2   No. 3

 Initial Sample Weight (mg)               50.78   46.50   45.70
 Weight  of  Ash After Ignition @ 400C(mg) 43.50   31.10   30.20
 Weight  Loss  on Ignition                 14.4%   33.1%   33.9%

 Total Fiber  in Sample (micrograms)        2.54    0.98    2.73
 Percent Fiber in Original Sample         0.005   0.002   0.006

 We were unable to determine the element distribution because
 our  emission spectrograph has been disassembled for  our move
 to Denver.
H-6

-------
Dr. M. G. Jacko
September 6, 1972
Page 2
If you have any questions regarding these samples or pro-
cedures you can contact Dr. Speil.  He will be available
through the month of September.  After that time you can
contact me in Denver.  Our mailing address and telephone
number in Denver will be:

           Johns-Manville Corporation
           P. O. Box 5108
           Denver, Colorado  80217

           Phone:   (303) 770-1000

Very truly yours,
  '/
J. P. Leineweber


mp


cc:  Dr. S. Speil
                                                         H-7

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