EPA-340/1-79-008
INSPECTION SOURCE TEST MANUAL
FOR
SOLVENT METAL CLEANING
(DEGREASERS)
EPA CONTRACT 68-01-4146
TASK ORDER 42
U.S. Environmental Protection Agency
Division of Stationary Source Enforcement
401 M Street, S.W.
Washington, D.C. 20460
EPA Project Officer: John R. Busik
EPA Task Manager: Robert C. Marshall
June 1979
-------
This report was prepared for the U.S. Environmental Protection Agency
by Engineering-Science of Durham, North Carolina in partial fulfillment
of Contract No. 68-01-4146. The contents of this report are reproduced
herein as received from the contractor. The opinions, findings and
conclusions expressed are those of the author and not necessarily those
of the U.S. Environmental Protection Agency.
ii
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ACKNOWLEDGEMENTS
This report was prepared under the direction of Roger D. Allen,
Manager of Air Quality, Engineering-Science. The principal investigators
were Mr. Allen, John T. Chehaske, Terranee A. Li Puma and Joseph Van Gieson.
Task Manager for the U.S. Environmental Protection Agency was
Mr. Robert C. Marshall. The authors appreciate the contributions made to
this study by Mr. Marshall and other members of the Office of Enforcement,
Division of Stationary Source Enforcement including Mr. Howard Wright,
Mr. Mark Antell, and Mr. Robert L. King. The authors also appreciate the
assistance provided by the staff of the Office of Air Quality Planning and
Standards, Emission Standards and Engineering Division, especially
Mr. Jeffrey L. Shumaker and Mr. K. W. Grimley.
We also wish to acknowledge the invaluable assistance by the following
organizations in taking the time to lend their expertise to the content of
this report:
Barren - Blakslee, Inc.
Chicago, Illinois
Delta Industries
Santa Fe Springs, California
Detrex Corp.
Detroit, Michigan
Graymills Corp.
Chicago, Illinois
Kleer-Flo Company
Eden Prairie, Minnesota
Naval Facilities Engineering Command
Atlantic Division
Norfolk, Virginia
Safety-Kleen
New Berlin, Wisconsin
iii
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CONVERSION FACTORS
1 KPa = 7.5 mm Hg (at 100°F) =7.5 Torr
- 0.15 psi (at 100°F)
1.03 bars
1m3 = 3.785 x 10~3 gallons
1.337 x lO"1 ft3
1m = 3.281 ft
1 cm = 3.937 x 10'1 in
1 in Hg = 13.60 in H20
1 liter = 2.642 x 1Q-1 gallons
1 ml = 2.642 x 10~^ gallons
1 yl = 10~6 liter
1 rag = 10~° gram
°K °C + 273
iv
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LIST OF ABBREVIATIONS
ASTM - American Society for Testing and Materials
Btu - British thermal unit
cfm - Cubic feet per minute
cm - Centimeters
°C - Degrees centigrade
CTG - Control Technology Guideline
dm - decimeter
EPA - Environmental Protection Agency
Ft - Feet
°F - Degrees farenheit
gal - Gallons
GC - Gas chromatography
Hg - Mercury
in - Inches
kPa - Kilograms per square centimeter (absolute pressure)
m - Meter
min - Minutes
mm - Millimeter
OSHA - Occupational Safety and Health Administration
ppm - Parts per million by volume
psi - Pounds per square inch
RACT - Reasonably available control technology
SIP - State Implementation Plan
TLV - Threshold limit value in ppm
VOC - Volatile organic compound
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TABLE OF CONTENTS
Chapter Page
1 INTRODUCTION 1.1-1
1.1 Scope and Objective of Manual 1.1-1
1.2 EPA's Policy on RACT Regulations for Degreasers 1.2-1
1.2.1 Application of Control Systems A and B 1.2-1
1.2.2 EPA's Policy on Exemptions 1.2-1
1.3 Degreasing Solvents 1.3-1
1.4 Inspection Equipment 1.4-1
1.5 Safety Considerations 1.5-1
2 COLD CLEANERS 2.1-1
2.1 Process Description 2.1-1
2.1.1 Unit Operation 2.1-1
2.1.2 Types of Cold Cleaner Degreasers 2.1-1
2.1.3 Operation of Degreaser Components 2.1-2
2.2 Atmospheric Emissions 2.2-1
2.2.1 Emission Points 2.2-1
2.2.2 Parameters Affecting Rate of VOC Emissions 2.2-1
2.3 Emission Control Methods 2.3-1
2.3.1 Other Controls 2.3-3
2.4 Inspection Procedures 2.4-1
2.4.1 Field Inspections 2.4-1
2.4.2 Record Review 2.4-4
2.4.2.1 Review of Design, Operation, and
Maintenance Data 2.4-6
2.4.2.2 Review Waste Solvent Disposal Procedures 2.4-8
3 OPEN TOP VAPOR DEGREASERS 3.1-1
3.1 Process Description 3.1-1
3.1.1 Unit Operation 3.1-1
3.1.2 Types of Open Top Vapor Degreasers 3.1-1
3.1.3 Operation of Degreaser Components 3.1-10
3.2 Atmospheric Emissions 3.2-1
3.2.1 Emission Points 3.2-1
3.2.2 Parameters Affecting Rate of VOC Emissions 3.2-3
3.3 Emission Control Methods 3.3-1
3.4 Inspection Procedures 3.4-1
3.4.1 Field Inspections 3.4-1
3.4.2 Record Review 3.4-6
3.4.2.1 Review of Design, Operation, and
Maintenance Data 3.4-6
3.4.2.2 Review Waste Solvent Disposal Procedures 3.4-8
4 CONVEYORIZED DEGREASERS 4.1-1
4.1 Process Description 4.1-1
4.1.1 Unit Operation 4.1-1
4.1.2 Types of Conveyorized Degreasers 4.1-1
4.1.3 Operation of Degreaser Components 4.1-6
vi
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TABLE OF CONTENTS (cont)
Chapter Page
4.2 Atmospheric Emissions ---------------------------------- 4.2-1
4.2.1 Emission Points --------------------------------- 4.2-1
4.2.2 Parameters Affecting Rate of VOC Emissions ------ 4.2-2
4.3 Emission Control Methods ------------------------------ 4.3-1
4.3.1 RACT Controls ---------------------------------- 4.3-1
4.3.2 Other Controls- --------------------------------- 4.3-3
4.4 Inspection Procedures ---------------------------------- 4.4-1
4.4.1 Field Inspections ------------------------------- 4.4-1
4.4.2 Record Review ----------------------------------- 4.4-8
4.4.2.1 Review of Design, Operation, and
Maintenance Data --------------------- 4.4-8
4.4.2.2 Review Waste Solvent Disposal Procedures 4.4-10
5 EMISSION TESTING OF CARBON ADSORPTION SYSTEMS --------------- 5.1-1
5 . 1 Introduction ------------------------------------------- 5.1-1
5.2 Source Testing Screening Method ------------------------ 5.2-1
5.2.1 Applicability ----------------------------------- 5.2-1
5.2.2 Principle --------------------------------------- 5.2-1
5.2.3 Range and Sensitivity --------------------------- 5.2-2
5.2.4 Calibration Apparatus ---------------- • ----------- 5.2-2
5.2.4.1 Calibration Apparatus for Use With
Commercially Prepared Calibration
Gas Mixtures ---------------------- 5.2-2
5.2.4.2 Calibration Apparatus for Use With
Standard Gas Mixtures Prepared from
Pure Solvent Liquid --------------- 5.2-3
5.2.5 Sampling and Analysis Apparatus ----------------- 5.2-4
5.2.6 Laboratory Calibration Procedures --------------- 5.2-4
5.2.6.1 Preparation of Standard Gas Mixture ---- 5.2-4
5.2.6.2 Determination of Analyzer Calibration
5.2.7 Sampling Procedures ---------------------------- 5.2-14
5.3 Draft Source Testing Compliance Verification Method ---- 5.3-1
5.3.1 Principle and Applicability --------------------- 5.3-2
5.3.1.1 Principle ----------------------------- 5.3-2
5.3.1.2 Applicability ------------------------- 5.3-2
5.3.2 Range and Sensitivity --------------------------- 5.3-2
5.3.3 Interferences --------------------------------- 5.3-2
5.3.4 Apparatus --------------------------------------- 5 . 3-2
5.3.4.1 Sampling ------------------------------ 5.3-2
5.3.4.2 Sample Recovery ------------------------ 5.3-5
5.3.4.3 Analysis ------------------------------- 5.3-5
5.3.4.4 Calibration ---------------------------- 5.3-6
J • j • 5 ^gQgQ0tS"~""—™""~""™'""""~"""~*~""p~~~~— "~~"""~™"— ™"~"""~~"™"""~™"~">"""""™" 3 * J~ /
5.3.5.1 Analysis ------------------------------ 5.3-7
5.3.5.2 Calibration ---------------------------- 5.3-7
5.3.6 Procedure -------------------------------------- 5.3-9
5.3.6.1 Sampling ------------------------------ 5 . 3-9
5.3.6.2 Sample Storage ------------------------- 5.3-9
5.3.6.3 Sample Recovery ------------------------ 5.3-9
5.3.6.4 Analysis ------------------------------- 5.3-10
5.3.6.5 Determine Ambient Conditions ---------- 5.3-10
vii
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TABLE OF CONTENTS (cont)
Chapter
5.3.7 Standards, Calibration, and Quality Assurance 5.3-10
5.3.7.1 Standards 5.3-10
5.3.7.2 Calibration 5.3-11
5.3.7.3 Quality Assurance 5.3-14
5.3.8 Calculations 5.3-15
5.3.8.1 Optional Standards Concentrations 5.3-15
5.3.8.2 Sample Concentrations 5.3-15
5.3.9 References 5.3-16
5.4 Material Balance 5.4-1
APPENDIX A. LIST OF REFERENCES
APPENDIX B CTG GUIDELINES
APPENDIX C SUPPLEMENT A: DETERMINATION OF ADEQUATE
CHROMATOGRAPHIC PEAK RESOLUTION
SUPPLEMENT B: PROCEDURE FOR FIELD AUDITING
GC ANALYSIS
viii
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LIST OF ILLUSTRATIONS
Figure Title Page
1-1 Solvent Vapor Pressure vs Temperature 1.3-4
1-2 Vapor Pressure vs Temperature for Chlorinated Solvents 1.3-5
2-1 Cold Cleaner 2.1-3
2-2 Spray Sink 2.1-4
2-3 Cold Cleaner Emission Points 2.2-3
2-4 Example Worksheet for Field Inspection of Cold Cleaners 2.4-2
2-5 Maintenance Cold Cleaner 2.4-5
2-6 Drainage Rack 2.4-5
2-7 Example Questionnaire for Office Review of Cold Cleaning
Degreasers 2.4-7
3-1 Single Compartment Vapor Degreaser 3.1-3
3-2 Liquid-Vapor Degreaser 3.1-4
3-3 Liquid-Liquid-Vapor Degreaser 2 Compartment 3.1-5
3-4 Liquid-Liquid-Vapor Degreaser 3 Compartment 3.1-5
3-5 Offset Condenser Vapor-Spray-Vapor Degreaser 3.1-6
3-6 Degreaser with Lip Exhaust • 3.1-6
3-7 Perimeter Condensing Vapor-Spray-Vapor Degreaser 3.1-7
3-8 Liquid-Liquid-Vapor Degreaser 2 Compartment 3.1-8
3-9 Liquid-Liquid-Vapor Degreaser 3 Compartment with Dip 3.1-9
3-10 Open Top Degreaser Emission Points 3.2-2
3-11 Refrigerated Freeboard Chiller 3.3-4
3-12 Example Worksheet for Field Inspection of Open Top Vapor
Degreasers 3.4-2
3-13 U.S. Environmental Protection Agency Open Top Va'por Degreaser
Summary 3.4-7
4-la Gyro Degreaser 4.1-2
4-lb Vibra Degreaser 4.1-2
4-2 Monorail Degreaser 4.1-3
4-3 Cross-Rod Degreaser 4.1-4
4-4 Mesh Belt Conveyorized Degreaser 4.1-5
4-5 Liquid-Liquid-Vapor Cross-Rod Degreaser 4.1-7
4-6 Typical Emission Points • ' 4.1-9
4-7 Example Worksheet for Field Inspection of Conveyorized
Degreasers 4.4-2
4-8 Cross Rod with Rotating Baskets 4.4-6
4-9 Cross Rod with Rotating Baskets (sketch) 4.4-7
4-10 Questionnaire for Conveyorized Degreasers 4.4-9
5-1 Example Calibration Curve Data Sheet 5.2-6
5-2 Apparatus for the Preparation of Calibration Gas Mixtures
from Liquid Solvent 5.2-7
5-3 Example Span Gas Preparation Data Sheet 5.2-9
5-4 Example Calibration Curve 5.2-13
5-5 Solvent Vapor Field Data Sheet for Screening of Carbon
Adsorption Systems on Vapor Degreasers 5.2-15
5-6 Integrated Bag Sampling Apparatus Assembly 5.3-3
5-7 Apparatus for the Preparation of Calibration Gas Mixtures from
Liquid Solvent 5.3-12
5-8 Material Balance Data Sheet —• 5.4-3
ix
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LIST OF TABLES
Table Title Page
1-1 Common Metal Cleaning Solvents 1.3-2
2-1 Control Systems For Cold Cleaning 2.3-2
3-1 Complete Control Systems For Open Top Vapor Degreasers 3.3-2
5-1 Injection Values For Preparation of Standards 5.2-10
5-2 Injection Values For Preparation of Standards 5.3-13
(Optional, See Section 5.3.7.1.1)
x
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CHAPTER 1
INTRODUCTION
1.1 SCOPE AND OBJECTIVE OF MANUAL
This document was prepared to assist U.S. Environmental Protection
Agency Regional Offices and state/local air quality control agencies in
implementing Reasonably Available Control Technology (RACT)l for volatile
organic compound (VOC) emissions from solvent metal cleaning processes
(more commonly referred to as degreasers) . Specifically, this manual
provides guidance in performing source inspections and compliance tests.
There are three basic types of solvent metal cleaning equipment;
manual cold cleaners, open top vapor degreasers, and conveyorized degreasers.
Chapters 2 through 4 discuss these operations, respectively. Each chapter
contains a description of the process, identification of the emission points
and the parameters that effect emissions, emission control methods, and a
suggested inspection procedure. For those degreasers equipped with carbon
adsorption control devices, it is necessary to perform emissions tests.
Chapter 5 contains EPA's draft procedure for testing solvent emissions and
also contains suggestions for performing screening tests and material
balances.
Additional topics in this introductory chapter include EPA's policy
regarding the implementation of RACT, identification of the solvents most
commonly used in degreasers, a listing of field equipment needed for
inspecting degreasers, and a discussion of the safety aspects of inspecting
degreasers.
Chapters and sections of this document have been arranged in a format that
permits easy and convenient replacement of material as information reflecting
more accurate and refined inspection and testing procedures are developed. To
speed dissemination of information, chapters or sections that contain new
procedures will be issued separate from the parent report whenever they are
revised. To facilitate the addition of future materials, the punched, loose-
leaf format was selected. This approach permits the document to be placed
in a three-ring binder or to be secured by rings, rivets, or other fasteners;
future supplements or revisions can then be easily inserted.
solvent metal cleaning operations, RACT is defined in the EPA Document
"Control of Volatile Organic Emissions from Solvent Metal Cleaning"
(EPA 450/2-77-022). This series of publications is also referred to as
the Control Technology Guideline (CTG) documents.
1.1-1
-------
1.2 EPA's POLICY ON RACT REGULATIONS FOR DEGREASERS
EPA's guidelines for RACT as applied to degreasers are contained in
Appendix B to this manual. Separate guidelines were issued for cold cleaners,
open top vapor degreasers, and conveyorized degreasers. Each guideline is
divided into two levels of control. Control System A consists of operating
practices and simple, inexpensive control equipment. Control System B con-
sists of System A plus additional requirements to improve the effectiveness
of control.
1.2.1 Application of Control Systems A and B
An approvable State Implementation Plan (SIP) must require the
application of Control System B throughout urban nonattainment areas
(>200,000 population) seeking an extension and to all facilities emitting
VOC's in excess of 100 tons per year in other nonattainment areas. Facil-
ities emitting 100 tons per year or less of VOC's in other nonattainment
areas must apply Control System A as a minimum. However, EPA encourages
states to control all degreasers in nonattainment areas to the Control
System B level.
1.2.2 EPA's Policy on Exemptions
The CTG recommends two exemptions for solvent metal cleaning processes.
First, conveyorized degreasers with an air/vapor interface of less than
2.0 square meters should be exempted from the requirement for a major
control device. Requirements for controlling these smaller units would
not be cost effective and would tend to move the small conveyorized degreaser
users to open top vapor degreasers which emit more solvent per unit of work.
Second, open top vapor degreasers with an open area of less than 1.0 square
meter of open area should be exempt from the application of refrigerated
chillers and carbon adsorbers since these controls would not be cost effec-
tive. These two exemptions are the only ones EPA will approve in urban
nonattainment areas. Blanket exemptions such as a 3 pound per day cutoff
or exemptions for cold cleaners will not be approved.
In rural nonattainment areas EPA will approve exemptions for sources
emitting less than 100 tons per year of VOC's. This would allow a blanket
exemption for cold cleaners since a typical cold cleaner emits approximately
0.3 tons per year. However, SIP's will not be approved that exempt all
open top vapor degreasers and conveyorized degreasers that individually emit
1.2-1
-------
less than 100 tons per year in rural nonattainment areas because large scale
users may have over 100 separate degreasing operations at one plant location.
If a State chooses to exempt open top or conveyorized degreasing operations
in rural nonattainment areas, the limitation should be 100 tons or less on
a facility-wide basis based on annual solvent purchase records. Further,
any exemption which distinguishes between open top vapor degreasers and con-
veyorized degreasers will not be approved because of the potential of switching
between equipment types. Although conveyorized degreasers are larger emitters,
they emit significantly less solvent than do open top vapor degreasers for an
equivalent workload. Thus, it would not be advantageous to encourage
degreaser operators to choose open top vapor degreasers in order to avoid
regulations on conveyorized degreasers.
1.2-2
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1.3 DECREASING SOLVENTS
Degreasing solvents are organic chemicals derived principally from
petroleum. They commonly include (i) petroleum distillates such as Stoddard,
kerosene, heptane and cyclohexane, (ii) halogenated hydrocarbons such as
methylene chloride, perchloroethylene, 1,1,1-trichloroethane, trichloroethy-
lene and trichlorotrifluoroethane (FC-113), (iv) oxygenated organics such as
acetone, methyl ethyl ketone, isopropyl alcohol and ethers, and (v) aromatics
such as toluene, turpentine and xylene. Table 1-1 summarizes some of the
important properties of common metal cleaning solvents.
Selection of a solvent for a particular application depends on the
type of cleaning to be done (cold or vapor), the nature of the grease and
other soil to be removed, and the level of cleanliness required. The pur-
pose of the solvent is to dissolve oils, grease, waxes, tars, and in some
cases, water. When these materials have been removed from the work,
insoluble material such as sand, metal chips, buffing abrasives and so
forth are flushed away at the same time. Consideration must be given to
nonmetallic portions of the work to be cleaned. For example plastic may
be dissolved or otherwise deteriorated by certain solvents. Other materials
may not be able to stand the heat necessary to boil high boiling solvents
in vapor degreasers.
Halogenated hydrocarbons are used universally in vapor degreasers
for two reasons. A very important consideration in solvent selection is
its flammability especially if the solvent must be heated to create a
vapor zone. The halogenated hydrocarbons used commonly in vapor degreasers
are nonflammable. Second, the vapors of halogenated hydrocarbons are
approximately four times more dense than air. This property enhances the
stability of the solvent vapor zone and thus reduces diffusion and convection
losses. Petroleum solvents are among the most widely used in cold cleaners,
especially in maintenance cleaners. If petroleum solvents are not adequate
for a particular cleaning application, the operator may turn to any of the
various alcohols, ketones, aromatics or halogenated hydrocarbons that are
capable of doing the job.
1.3-1
-------
TABLE 1-1
ho
COMMON METAL CLEANING SOLVENTS****
Solvency for
Type of Solvent/ Metal Working
Alcohols
Solvent
Ethanol (95Z)
Isopropanol
Methanol
Aliphatic Hydrocarbons
Heptane
Kerosene
Stoddard
Mineral Spirits 66
Aromatic Hydrocarbons
Benzene***
Chlorinated
Fluorinated
Ke tones
SC 150
Toluene
Turpentine
Xylene
Solvents
Carbon Tetrachloride***
Methylene Chloride
Perchloroethylene
1 , 1, 1-Tr ichloroe thane
Trichloroethylene
Solvents
Trichlorotrifluoro-
ethane (FC-113)
Acetone
Methyl ethyl ketone
Soils
poor
poor
poor
good
good
good
good
good
good
good
good
good
excellent
excellent
excellent
excellent
excellent
good
good
good
TLV
(ppm)
1000*
400*
200*
500*
500
200
200
10*
200
200*
100*
100*
10*
500*
100*
350*
100*
1000*
1000*
200*
Flash
Point
60°F
55°F
58°F
<20°F
149°F
105°F
107°F
10°F
151°F
45°F
91°F
81°F
none
none
none
none
none
none
<0°F
28°F
Evaporation
Rate**
24.7
19
45
26
0.63
2.2
1.5
132
0.48
17
2.9
4.7
111
363
16
103
62.4
439
122
45
Water
Solubility Boiling Point
(Z wt.) (Range)
oo 165-176°F
oo 179-181°F
oo 147-149°F
<0.1 201-207°F
<0.1 354-525°F
<0.1 313-380°F
<0. 1 318-382°F
<0.1 176-177°F
<0.1 370-410°F
<0.1 230-232°F
<0.1 314-327°F
<0.1 281-284°F
<0.1 170-172°F
0.2 104-105. 5°F
<0.1 250-254°F
<0.1 165-194°F
<0.1 188-190°F
<0.1 117°F
oo 132-134°F
27 174-176°F
Pounds
Per Gal.
6.76
6.55
6.60
5.79
6.74
6.38
6.40
7.36
7.42
7.26
7.17
7.23
13.22
10.98
13.47
10.97
12.14
13.16
6.59
6.71
Price
Per Gal.
$ 1.59
$ 1.26
$ 1.11
$ 0.86
$ 0.66
$ 0.62
$ 06.2
$ 1.06
$ 0.90
$ 2.40
$ 0.96
$ 3.70
$ 2.83
$ 3.33
$ 2.78
$ 3.13
$ 7.84
$ 1.45
$ 1.74
(ml/dm/min) (Dow Chemical Co., method).
•Federal Register, June 27, 1974, Vol. 39, No. 125.
**Evaporation Rate determined by weight loss of 50 mis in a 125 ml beaker on an analytical balance
***Not recommended or sold for metal cleaning (formerly standards in industry).
****prlmary source from The Solvents and Chemicals Companies "Physical Properties of Common Organic Solvents" and Price List
(July 1, 1975).
-------
Evaporative losses in cold cleaners increase as the volatility of
the solvent increases. In addition, cold cleaning solvents are sometimes
heated or agitated to improve cleaning, further increasing evaporative
losses. EPA has included more stringent control requirements under Control
System B for the more volatile solvents. Figures 1-1 and 1-2 provide the
vapor pressures of a number of solvents as a function of temperature.
1.3-3
-------
FIGURE 1-1
Ul
ee.
CO
oo
SOLVENT VAPOR PRESSURE VS. TEMPERATURE
1000
900
800
700
600
500
400
300
200
100
90
80
70
60
50
40
30
20
1. Heptane
2. 1,1,1-Trichlorotrifluoroethane
3. Acetone
4. Methanol
5. Benzene
6. Methyl Ethyl Ketone
7. Ethane
8. Isopropyl Alchohol
9. Toluena
10
20
30
I 40
38°C
50
60
80
TEMPERATURE (°C)
1.3-4
-------
FIGURE 1-2
VAPOR PRESSURE VS TEMPERATURE FOR CHLORINATED SOLVENTS
E
oo
oo
LU
o:
a.
o:
o
D.
IUUU
900
800
700
600
500
400
300
200
100
90
80
70
60
50
40
30
20
1
•
X
/
/
//
^
/
>
/
/
2
//
x
^
/
/
'
^/
Xi
'
,
X
x
^x
^
/8
/10
£^>
3
5
y 7
^9
1. Hethylene Chloride 6. Ethylene Dichloride
2. 1 ,1-Dichloroethane 7. Trichloroethylene
3. Chloroform 8. 1 ,1 ,2-Trichloroethane
4. 1 ,1 ,1-Trichloroethane 9. Perchloroethylene
5. Carbon Tetrachloride 10. Stoddard Solvent*
i i
20 30 40 50 60 70 81
38°C
TEMPERATURE (°C)
*Stoddard is not a chlorinated solvent
1.3-5
-------
1.4 INSPECTION EQUIPMENT
The inspector should arrive at the plant with all the necessary per-
sonal safety and testing equipment. The requisite personal safety equipment
will depend on the nature of the activities at the plant; the inspector
should be prepared with the minimal routine items, that is, a hard hat,
steel-toed shoes and safety glasses.
Field equipment specific to degreaser inspections should include the
following:
o Tape measure for measuring degreaser area and stack dimensions
o Thermometer (dial type) for measuring condensor coil water
temperature
o Stop watch for timing operational procedures
o Small plastic bottle for collecting sample of condensor coil
water
o Swinging vane velocity meter (velometer) for measuring exhaust
stack velocity
o Refer to Chapter 5 for a list of stack testing equipment
A thorough discussion of inspection equipment, general field enforce-
ment activities and inspection techniques may be found in ""Field Operations
and Enforcement Manual for Air Pollution Control, Volume I: Organization
and Basic Procedures". EPA Publication Number APTD-1100 (NTIS Publication
No. PB 213008, $10.75).
1.4-1
-------
1.5 SAFETY CONSIDERATIONS
All of the solvents used in degreasers have toxic characteristics
if inhaled at sufficient concentration levels (see Table 1-1). It should
never be necessary for the air pollution inspector to enter a drained
degreaser sump. Several safety precautions are necessary (ventilation,
safety harnesses, respirators, tests for flammability of vapors, etc.)
that are best left to the operators that are properly trained in the safety
requirements.
Most solvents are flammable, and even those that are not may develop
flammable or even explosive mixtures in the sump, depending on the nature
of the contaminants. Do not smoke near a degreaser.
Transfer of solvent into the degreaser or into waste storage con-
tainers can cause splashing. The inspector should stand clear of these
operations.
Heat is another potential hazard. Vapor degreaser walls may be hot
enough to burn hands. Never put hands below the vapor level inside a vapor
degreaser. These vapors can exceed 200°F and are extremely powerful solvents.
1.5-1
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CHAPTER 2
COLD CLEANERS
2.1 PROCESS DESCRIPTION
2.1.1 Unit Operation
Manually operated cold cleaners provide solvent degreasing for low
volume workloads of small, variably shaped automotive and general plant
maintenance parts, and for fabricated metal products. The basic steps
involved in degreasing with a cold cleaner include soaking with solvent
in the dip tank, and drying the work of solvent after cleaning.
The solvent dissolves the dirt/grease on the part to be cleaned
as it is immersed. The part is usually lowered into the solvent bath
in a metal basket. The cleaning action is often enhanced by agitation
of the solvent and by spraying solvent on the part. After cleaning
the part is dried by allowing evaporation and drainage of the solvent
on drying racks which are located inside the cleaner or on external racks
which route the drainage back into the cleaner.
Many cold cleaners which are equipped with sprayers or pump agitation
utilize filters in the pump piping system to remove sludge and dirt thus
extending the useful life of the solvent.
2.1.2 Types of Cold Cleaner Degreasers
Cold cleaners can be generally classified as maintenance and manu-
facturing degreasers. Maintenance cold cleaners are by far more common
and are used for automotive and plant maintenance cleaning. Maintenance
cold cleaners are usually smaller, simpler and less expensive than manu-
facturing cleaners. A typical size of maintenance cold cleaners is
approximately 0.4 m2 (4 ft2) of opening and 0.1 m3 (30 gallon) solvent
capacity.
Manufacturing cold cleaners are employed in applications where a
larger volume workload, a higher degree of cleaning and larger parts to
be cleaned dictate the use of larger more specialized degreasers. Manu-
facturing cold cleaners are usually found in metal fabrication facilities.
The larger size, greater workload and higher solvency needed to achieve
the degree of cleaning required of manufacturing cold cleaners result in
more solvent emissions than is usually released by maintenance cold cleaners.
2.1-1
-------
The variety of specific applications for cold cleaners offers a
method for more accurately classifying cold cleaners by agitation techni-
que and tank design.
The two basic designs are the dip tank and the spray sink, although
many cold cleaners employ both cleaning methods. Dip tank cleaners (Figure
2-1) allow for more thorough cleaning by providing for soaking dirty parts
in the liquid solvent bath. The spray sink (Figure 2-2) is simple, inexpen-
sive and used when a relatively low degree of cleanliness is required. As
can be seen from Figure 2-2, the liquid solvent tank is not accessible
for soaking parts; however, solvent losses due to bath evaporation are
insignificant with this arrangement.
2.1.3 Operation of Degreaser Components
Agitation of the liquid solvent in dip tanks further improves clean-
ing efficiency and can be provided by pumping, compressed air, vertical
motion or ultrasonic vibration. Pump agitation rapidly circulates solvent
through the tank. Compressed air is dispersed from the bottom of the tank
in air agitation. The rising bubbles scrub the surface of the work. Ver-
tically agitated cold cleaners vibrate the dirty parts up and down in the
tank with a motor driven, cam actuated device usually operated at 60-70
cycles per minute. Ultrasonic agitation vibrates the solvent with high
frequency sound waves. This vibration causes cavitation, the implosion
of bubbles of vaporized solvent on the surface of the parts, which breaks
down the dirt film. To optimize cavitation, the solvent is usually heated
to a specific temperature.
Other degreaser components that are discussed in this chapter
include the cover, spray pump and hose, internal and external drain
boards and the parts basket.
2.1-2
-------
2-1
Cleaner
-------
Figure 2-2
SPRAY SINK
(Safety-Kleen, New Berlin, Wisconsin)
2.1-4
-------
2.2 ATMOSPHERIC EMISSIONS
2.2.1 Emission Points
Solvent evaporation is the basic emission mechanism for cold cleaners
and the emission rates vary with size, frequency of use, and manner of their
operation. Based on national consumption data, cold cleaners each emit an
average of 0.3 metric tons of solvent vapor per year. Maintenance cold
cleaners emit an average of 0.25 metric tons per year and manufacturing cold
cleaners emit an average of 0.5 metric tons per year. Emissions from manu-
facturing cleaners are larger primarily because their units are used more
steadily in the course of a work day than maintenance clraners.
There are several means by which organic solvent vapors can be
emitted to the atmosphere from a cold cleaner. These are illustrated
in Figure 2-3. Cold cleaners are very rarely hooded or vented to the
outside. Thus, an obvious emission point is the direct evaporation of
solvent from the tank to the atmosphere (Location 1). Carry out emissions
(Location 2) result from liquid solvent that is physically carried out
of the degreaser on the cleaned parts and subsequently evaporates. Mechan-
ical agitation of the solvent bath (Location 3) increases evaporative losses.
Turbulence from spraying (Location 4) increases emissions as does overspray-
ing (spraying outside the tank), and excessive spray velocity. Finally,
the emissions from the disposal of waste solvent (Location 5) can vary
significantly, depending on the techniques employed.
2.2.2 Parameters Affecting Rate of VOC Emissions
Bath evaporation occurs whenever the degreaserfs hood is open but
is increased by air movement such as drafts or ventilation and is directly
related to the evaporation rate of the solvent used. The solvents most
commonly used by cold cleaners are Stoddard solvents, safety solvents
(blends of chlorinated hydrocarbons and petroleum solvents), ketones and
fluorinated solvents.
Bath evaporation can be minimized during operation when adequate
freeboard height (distance from solvent level to top of the cold cleaner)
is employed. Freeboard height requirements are often expressed as free-
board ratio, which is the ratio of freeboard height to the width of the
degreaser.
2.2-1
-------
Bath evaporation emissions can be further reduced by keeping the
degreaser cover closed during degreasing operations except when parts are
removed from or added to the degreaser. Various types of covers are
available. Sliding plastic covers which roll up on a rotating shaft at
one end of the degreaser when not in use are the most simple and easy to
use. Some large degreaser covers use counterweights. Electrically or
pneumatically powered covers are also used. Guillotine covers are another
easily operated type found on many degreasers. Generally, the amount of
effort required will dictate the frequency of use of the cover and therefore
dictate the amount of bath evaporation. Hatch type covers such as the one
shown in Figure 2-3 usually have a fusible link support arm so that they
will slam shut in the event that a fire breaks out. Local fire and safety
codes often require such devices.
Air flow into the tank also influences solvent evaporation. The
degreaser should be located to minimize evaporative losses due to work
fans and ventilation ducts. Partitions, curtains or baffles help create
a still air zone around the degreaser and can reduce bath evaporation
emissions.
Control devices are required for cold cleaners with heated (>50°C)
or highly volatile (volatility >4.3 Kpa measured at 38°C) solvent. (The
term "cold cleaner" applies even if the solvent is heated, as long as the
objective is not to create a vapor zone.) The control devices which comply
with the RACT guidelines are refrigerated chillers, freeboard ratios >0.7,
carbon adsorption and water blankets. If properly applied, maintained and
operated, these control devices can significantly reduce solvent emissions.
Refrigerated chillers are condensing coils located peripherally
along the freeboard, which condense the solvent vapor before escaping
from the degreaser. Carbon adsorption is a device which reclaims solvent
from the air/vapor mixture escaping the cleaner. These are rarely used
on cold cleaners.
A water blanket is a layer of water in the dip tank on top of the
solvent which provides a vapor barrier between the solvent and the atmos-
phere. The solvent must be heavier than and insoluble in water.
Carry-out emissions occur when wet parts are removed from the
degreaser and are influenced by: drying procedure, location and type of
drying racks, s±ze of the parts being cleaned, and the volume of the work-
load.
2.2-2
-------
I) CARRY-OUT
COMPRESSED AIR
5) WASTE SOLVENT
Figure 2-3. Cold Cleaner Emission Points
2.2-3
-------
Drainage of any solvent entrained in crevices or depressions in
the parts prior to moving them to external drying racks, and closing the
hood during drying if internal racks are used, minimizes carry-out emissions.
If external racks are employed, drains which return the carried-out solvent
to the degreaser tank reduce solvent loss. As recommended from ASTM D-26,
cleaned parts should be drained for 15 seconds.
The surface area of the parts workload affects carry-out since the
mass-transfer of solvent by evaporation is directly proportional to the
amount of solvent-laden surface area.
Agitation increases emissions. Agitation intensity, amount of heat
input, if any, and solvent volatility all affect VOC emissions from cold
cleaners. Proper operating procedures can minimize emission during agita-
tion. Emissions are insignificant if the cover is closed during agitation
and the bath should be agitated only during cleaning. If air or pump
agitation is used, the flow rate should be adjusted to the minimum amount
required to achieve the desired degree of cleaning. Air flow rate should
o
not exceed 0.01 to 0.03 m per minute per square meter of opening.
Evaporation from spraying will vary with spray pressure, spray
droplet size and distribution, amount of overspray which splashes from
the sink, solvent volatility and amount of time the spray is in use.
Spray operating techniques can lower emissions. Care to eliminate
overspray, adjusting spray to a solid fluid stream and limiting spray fluid
pressure to a maximum of 10 psig will reduce solvent losses by evaporation.
Waste solvent evaporation is the single largest mechanism for solvent
emissions from cold cleaning. The amount of solvent disposed by a single
degreaser is dependent upon the degreaser size, frequency of operation,
degree of cleanliness required and amount of oil and dirt to be removed.
If a cold cleaner spray system is equipped with a filter, the frequency of
disposal is reduced.
Leaks in spray lines and agitation pump discharge lines which are
under pressure can cause significant solvent emissions. Pipe flanges,
drain valves, corroded tanks (especially when using an acidic solvent or
if water is present in the solvent) can also leak if not properly maintained.
2.2-4
-------
Acceptable methods of disposal include recycling by distillation,
proper incineration, distillation (recovery of solvent for re-use) and
chemical landfilling if waste is enclosed in sealed containers and surrounded
by impermeable soil.
Disposal by flushing solvent into sewers, spreading solvent for dust
control and landfilling without proper containers or prevention of leaching
all result in complete evaporative emissions of waste solvent to the atmos-
phere.
Solvent emissions are greatly influenced by the type of solvent.
Obviously volatility and operating temperatures are significant parameters
affecting emissions. Highly toxic solvents are more conscientiously
controlled to protect workers and comply with OSHA regulations. Solvent
costs often determine the care with which degreasers are operated. More
expensive solvents are usually conserved by the same procedures which
reduce emissions and are more likely to be recycled.
2.2-5
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2.3 EMISSION CONTROL METHODS
The EPA Control Technology Guideline (CTG) document for solvent metal
cleaning identifies a number of control strategies for reducing volatile
organic emissions from cold cleaning degreaser operations. These form the
basis of defining RACT for the cold cleaning degreasers and should therefore
be the focal point of a field inspection. The CTG suggests two levels of
control. (See Table 2-1). Level A could reduce cold cleaning emissions by
50% (+20%) and Level B may achieve a reduction of 53% (+20%). The range
represents the limits of reduction for poor operating procedure (-20%) and
good operating procedure (+20%). The estimated benefit from Level B only
slightly exceeds that from Level A, assuming low volatility solvents. This
is because the additional devices required in Level B generally control only
bath evaporation which represents only 20% to 30% of the total emissions
from an average cold cleaner. For cold cleaners using highly volatile
solvents, bath evaporation may constitute 50% of the total emissions, and
it is estimated that Level B would then achieve an emissions reduction of
69% (+20%) and a 55% (+20%) reduction for Level A.
The preceding discussion on the parameters affecting the rate of
VOC emissions (Section 2.2.2) explicitly identifies the equipment and
operating procedures necessary to implement the RACT control strategies
except for the disposal of waste solvent. Dirt, grease, oil, metal chips
and the like slowly build up in the liquid solvent over a period of time
and eventually severely affects its ability as a cleaning agent. This
usually occurs when the solvent contamination level reaches about 10
percent by volume. It is fairly common for the small operator to secure
a service contract that provides for reclaiming the spent solvent. The
contractor distills the spent solvent and returns it to users for a fee.
One organization rents the cold cleaner and provides the solvent reclama-
tion service as a package deal. Large operations that use scores of
manufacturing cold cleaners sometimes operate stills on-site to reclaim the
solvent. Distillation, proper landfilling, and incineration (which is
not commonly used) will meet the RACT operating requirements ("not greater
than 20 percent can evaporate into the atmosphere"). Disposal of the
waste solvent (and still bottoms) at landfills may be subject to hazardous
waste disposal regulations. EPA has proposed regulations governing the
disposal of such material in the Federal Register at 43FR58946 (December 18,
1978).
2.3-1
-------
TABLE 2-1
CONTROL SYSTEMS FOR COLD CLEANING
Control System A
Control Equipment
1. Cover
2. Facility for draining cleaned parts
3. Permanent, conspicuous label, summarizing the operating requirements
Operating Requirements:
1. Do not dispose of waste solvent or transfer it to another party,
such that greater than 20 percent of the waste (by weight) can evaporate
into the atmosphere.11' Store waste solvent only in covered containers.
2. Close degreaser cover whenever not handling parts in the cleaner.
3. Drain cleaned parts for at least 15 seconds or until dripping ceases.
Control System B
Control Equipment:
1. Cover: Same as in System A, except if (a) solvent volatility is
greater than 2 kPa (15 mm Hg or 0.3 psi) measured at 38°C (100°F),**
(b) solvent is agitated, or (c) solvent is heated, then the cover must
be designed so that it can be easily operated with one hand. (Covers for
larger degreasers may require mechanical assistance, by spring loading,
counterweighting or powered systems.)
2. Drainage facility: Same as in System A, except that if solvent
volatility is greater than about 4.3 kPa (32 mm Hg or 0.6 psi) measured at
38°C (100°F), then the drainage facility must be internal, so that parts are
enclosed under the cover while draining. The drainage facility may be
external for applications where an Internal type cannot fit into the cleaning
system.
3. Label: Same as in System A
4. If used, the solvent spray must be a solid, fluid stream (not a
fine, atomized or shower type spray) and at a pressure which does not cause
excessive splashing.
5. Major control device for highly volatile solvents: If the solvent
volatility is > 4.3 kPa (33 mm Hg or 0.6 psi) measured at 38°C (100°F), or
if solvent is heated above 50°C (120°F), then one of the following control
devices must be used:
a. Freeboard that gives a freeboard ratio*** ^0.7
b. Water cover (solvent must be insoluble in and heavier than water)
c. Other systems of equivalent control, such as a refrigerated chiller
or carbon adsorption.
Operating Requirements:
Same as in System A
*Water and solid waste regulations must also be complied with.
**Generally solvents consisting primarily of mineral spirits (Stoddard) have
volatilities - 2 kPa.
***Freeboard ratio is defined as the freeboard height divided by the width
of the degreaser.
2.3-2
-------
2.3.1 Other Controls
Where work being degreased contains acid cutting oils or other
acidic products, acid acceptance and PH determination should be made to
ascertain the quality of the solvent.
Absorbent materials such as wood or fabric materials should not be
degreased or used in basket construction.
The cold cleaner should be inspected for solvent leaks and repairs
should be made as necessary.
2.3-3
-------
2.4 INSPECTION PROCEDURES
This section will discuss two types of inspections: (1) field
review and (2) office reviews. Source sampling, still another form of
inspection, is only feasible for measuring the stack gases from carbon
adsorbtion systems which are rarely used for cold cleaning degreasers.
Field inspections range from plant visits to thorough inspections
that produce a complete data base for enforcement proceedings. Office
reviews rely on the source to furnish the information. This approach may
require less time and manpower but the resulting data base is generally
less complete. Office reviews, however, provide a useful screening
mechanism where the number of potential violators is large.
2.4.1 Field Inspections
After becoming familiar with the plant and its facilities the
inspector should request that the appropriate company official provide
information from company records that will allow the inspector to complete
the worksheets shown in Figure 2-4. The data may also be available from
permit applications. The worksheet divides the required data into two
categories: operating requirements and control equipment. It also
provides the RACT requirements for each category with suggested inspec-
tion procedures and guidelines. With such information, comparisons can
be made with past conditions, and with operations at the time of the
inspection.
Generally, the inspector would next request the company's assistance
in conducting a full inspection of the facility in order to verify actual
operating conditions. This inspection may take several hours depending on
the number and types of degreasers.
All field data such as solvent temperature and type should be
measured or observed first hand. Auxiliary degreaser components (sprayer,
agitator, etc.), and waste solvent, recovery, disposal or storage facilities
should be seen and verified. Operating procedures should be observed and
noted. Degreasers should be inspected for condition of hoses, connections,
drains and for leaks^ The inspector should check for ventilation ducts,
location of work fans and air flow baffles near the degreaser which may
affect solvent evaporation rate. The inspection should include evaluation
of those parameters which influence emissions as discussed earlier in this
chapter.
2.4-1
-------
FIGURE 2-4
EXAMPLE WORKSHEET FOR FIELD INSPECTION OF
COLD CLEANERS
1. BUSINESS LICENSE NAME OF CORPORATION, COMPANY, OR INDIVIDUAL OWNER OR GOVERNMENTAL AGENCY:
2a.
3.
It.
5.
6.
7.
MAILING ADDRESS: 2b. PLANT ADDRESS WHERE THIS DEGREASER IS LOCATED:
SOURCE NO. (PERMIT NUMBER, NEDS ID, ETC.):
NAME AND TITLE OF COMPANY REPRESENTATIVE:
TELEPHONE NO.:
NAME OF OFFICIAL CONDUCTING INSPECTION:
DEGREASER
MANUFACTURER: MODEL NO. SERIAL NO.
INSIDE DIMENSIONS OF TANK (FT.): WIDE X LONG X DEEP
TYPE OF DEGREASER: SPRAY SINK [~~| DIP TANK [~~|
8.
9.
TITLE AND CODE NUMBERS OF DRAWINGS, SPECIFICATIONS, STANDARDS, CODES, PROCEDURES AND DOCUMENTS USED WITH THE
INSPECTION
TYPE OF SOLVENT IN USE (SPECIFIC NAME AND MANUFACTURER) :
INSPECTION OBSERVATIONS
RACT REQUIREMENT
1.
2.
3.
4.
CONTROL EQUIPMENT
Cover
Cover must be easily
operated with one hand
if:
- Solvent volatility
>2 kPa (measured at
38°C)
- Solvent is agitated
- Solvent is heated
Drainage Facility
Internal drainage
facility is required
if:
- Solvent volatility
> 4.6 kPa (measured
at 38°C)
SUGGESTED INSPECTION
PROCEDURE
o Observe if a cover is Installed
and if it is closed when parts
are not being handled in the
degreaser.
o Observe if cover can be operated
with one hand. Observe if solvent
is heated or agitated. If degreaser
cover is large, check for mechani-
cal assistance for operation. Deter-
mine the solvent type and its vola-
tility. Vapor pressures for common
solvents can be found in Chapter 1
of this manual.
o Observe if drainage racks are
provided. If drainage racks are
external to the degreaser, observe
if drainage is routed to the solvent
bath.
o Observe if drainage racks are
internal. Determine solvent
volatility.
FIELD
OBSERVATION
2.4-2
-------
FIGURE 2-4
(Continued)
RACT REQUIREMENT
5. Solvent spray must be
a solid fluid stream
and at a pressure that
does not cause splash-
ing.
6. Permanent conspicuous
label summarizing
operating require-
ments.
7. If solvent volatility
>4.3 kPa measured at
38°C, or solvent temp-
erature is > 50°C then
one of the following
control measures must
be used.
a. Freeboard Ratio
>_ 0.7
b. Water Cover
c. Other systems of
equivalent control
such as chiller
or carbon adsorb-
tion
OPERATING REQUIREMENTS
1. Do not dispose of
waste solvent or trans-
fer it to another party
such that greater than
20% (by weight) can
evaporate to the atmos-
phere. Store waste
solvent only in covered
containers.
2. Close degreaser cover
whenever not handling
parts in the cleaner.
3. Drain parts for at
least 15 seconds or
until parts are dry.
SUGGESTED INSPECTION
PROCEDURE
o Observe If spray forms a mist
or shower type consistency. Check
for splashing above degreaser free-
board
o Observe if label is clearly displayed,
complete and permanently fastened to
degreaser
o Determine if requirement is appli-
cable
o Measure solvent temperature
(if heated) with thermometer
o Calculate from degreaser
dimensions. Freeboard ratio -
Freeboard
Width
o Observe if the solvent
is covered with water.
o Determine if appropriate device is
installed and operational
o Determine if source has inhouse
reclamation facility (i.e. still)
or a service contract with a
solvent reclamation firm.
o Confirm that storage is done
with covered containers. Note
whether containers leak.
o Observe the operation
o Observe this operation. Time if
necessary, or determine if parts
are dry when removed from drying
rack.
FIELD
OBSERVATION
2.4-3
-------
If the degreaser is not in use then only design data and records
review can be performed during the field inspection. Maintenance degreasers
are used intermittantly and may not be operating during the inspections.
Manufacturing cold cleaners are generally an integral part of a manufacturing
process and normally will be operating. It is important to note that
operating procedures (use of cover, drain and drying time, spray technique)
can have a significant impact on solvent emissions regardless of equipment
design.
The information gathered during the field inspection will be compared
to the data given by the company official, and the total data base will be
compared to the RACT requirements for design, operating and control require-
ments to determine if a violation exists. At that time, a reinspection date
should be established if it is determined that the source is not in compliance.
Figures 2-5 and 2-6 are photographs of a maintenance cold cleaner
of a design that would typically be encountered by an inspector. In
Figure 2-5 the rectangular box in the corner of the tank contains the
spray pump, the cylindrical housing contains pump filter. Figure 2-6 shows
that this cleaner has been equipped with two spray hoses; the flexible metal
hose is the original equipment, the garden hose and nozzle was retrofitted
by the operator in order to increase the spray velocity. This arrangement
potentially violates the RACT requirement that the solvent spray must be
"...a solid, fluid stream (not a fine, atomized or shower type spray) and
at a pressure that does not cause excessive splashing". Also, note the pan
located underneath the drainage rack. Drippings from drying parts are
accumulated on the pan, rather than returned to the tank. This increases
the surface area of solvent, thus increasing evaporative losses.
2.4.2 Record Review
Determining compliance of cold cleaning degreasers through field
inspections and monitoring is expensive and time consuming. It requires
a great deal of manpower and tends to limit the number of sources that can
be reviewed in a given year. The review of company-furnished records
through questionnaires or letter requests may provide a viable alternative
to field inspections and source monitoring activities for compliance deter-
mination. At minimum, this approach should be considered as a screening
tool to identify candidate sources for comprehensive field inspections,
thereby increasing the effectiveness of the available resources.
2.4-4
-------
Figure 2-5
MAINTENANCE
COLD
CLEANER
Figure 2-6
DRAINAGE
RACK
2.4-5
-------
This discussion outlines several procedures which may be used when
implementing a record review. Information will be required from the plant
concerning the design, operation and maintenance of the equipment.
When screening sources for setting inspection priorities by office
review of questionnaires, the estimated average emission rates of 0.25
metric tons per year for maintenance cold cleaners and 0.50 metric tons
per year for manufacturing cold cleaners can be applied to individual
degreasers to estimate the total cold cleaning solvent emissions for a
specific source. Comparison of the total emissions for each source can
aid in allocating manpower for inspections to achieve effective use of
an enforcement agencies resources.
2.4.2.1 Review of Design, Operation, and Maintenance Data
The first requirement of this procedure is the development of
standard questionnaires that can be sent out as part of a Section 114
request to the applicable sources. The type of information required is
similar to what is identified on the inspection forms illustrated in
Figure 2-4. It is important that the source understand what is being
requested and that the request be realistic because the entire process of
making compliance judgments using this procedure is highly dependent on
the reliability of the information furnished.
An example questionnaire is provided as Figure 2-7 and should
be used as a guide only. It is suggested that the agency develop its
own form which would be specific to the program. For example, a screening
program may only require key data, while a more extensive request is
necessary if compliance determinations are to be attempted. Three types
of data are suggested for review: design information, operational infor-
mation, and maintenance records. The design data should be readily avail-
able, while operational and maintenance may require the source to create
a special logging system in order to comply with the agency's request.
Design data should be compared to the RACT requirements and review
should include such items as degreaser dimensions, solvent bath volume,
solvent type, auxiliary components (agitation, spray, etc.) and type of
cover and drainage facility. Operational information such as solvent
makeup schedule (if any) and rate, disposal schedule and procedure, and
frequency of degreaser operation should be reviewed. Maintenance records
should report repair or replacement records and comment on the general
condition of the equipment.
^-. 4-6
-------
FIGURE 2-7
EXAMPLE QUESTIONNAIRE FOR OFFICE REVIEW
OF COLD CLEANING DEGREASERS
GENERAL
1. BUSINESS LICENSE NAME OF CORPORATION, COMPANY, OR INDIVIDUAL OWNER OR GOVERNMENTAL AGENCY:
2a. MAILING ADDRESS:
2b. PLANT ADDRESS WHERE THIS DEGREASER IS LOCATED:
3. SOURCE NO. (PERMIT NUMBER, NEDS ID, ETC.):
it. NAME AND TITLE OF AUTHORIZED COMPANY REPRESENTATIVE FURNISHING DATA:
SIGNATURE:
5. TELEPHONE NO.:
6. DEGREASER:
MANUFACTURER:
INSIDE DIMENSIONS OF TANK (FT) :_
DIP TANK |—-i SPRAY SINK | 1
_MODEL NO.
WIDE X
LONG X
_SERIAL NO.
DEEP
7. TYPE OF SOLVENT IN USE (SPECIFIC NAME AND MANUFACTURER):
8. EQUIPMENT DESIGN
TANK COVER: YES j | NO | [
DRAINAGE BOARD YES | | NO | |
INTERNAL ||
EXTERNAL ||
DRAINAGE RETURN (IF EXTERNAL) j |
SOLVENT SPRAY: YES [^] NO | I
SPRAY PRESSURE PSI
AGITATION: YES | | NO | |
PUMPED | | MECHANICAL | |
AIR | | ULTRASONIC | [
HEATED: YES Q]] NO | j
IF HEATED, GIVE TEMPERATURE °F
FREEBOARD HEIGHT
FT
9. OPERATING PROCEDURE
CAN DEGREASER COVER BE CLOSED DURING DEGREASER OPERATION? YES | [ NO I I
IS DEGREASER COVER CLOSED WHEN DEGREASER IS NOT IN USE? YES | | NO | |
ARE PARTS DRY BEFORE REMOVAL FROM DRYING RACK?. YES £^[ N0 d
HOW IS WASTE SOLVENT DISPOSED OF:
FREQUENCY OF MAKEUP
10. CONTROL DEVICES:
REFRIGERATION CHILLERS YES | I NO | [
CARBON ADSORBTION YES | [ NO | [
WATER COVER YES | | NO | |
FREEBOARD RATIO >_ 0.7 YES | [ NO | |
11. DESCRIPTION OF MAINTENANCE PROGRAM:
2.4-7
-------
2.4.2.2 Review Waste Solvent Disposal Procedures
A description of waste solvent disposal methods used by the source
must be requested in the questionnaire initiated by the agency (example
shown in Figure 2-7) . A comparison should be made with the RACT operating
requirements ("not greater than 20 percent can evaporate into the atmosphere"),
and data on other acceptable practices which are readily available.
Several acceptable methods for disposing of waste solvent were briefly
discussed in Section 2.3. Common disposal methods that do not meet the
RACT guidelines include flushing waste solvent into sewer lines and spreading
waste solvent on parking lots and roadways for dust control purposes.
2.4-8
-------
CHAPTER 3
OPEN TOP VAPOR DEGREASERS
3.1 PROCESS DESCRIPTION
3.1.1 Unit Operation
Open top vapor degreasers provide an efficient and economical method for
preparing clean, dry articles for subsequent finishing or fabricating. There
are several configurations in use for open top degreasers; all are similar in
basic design. In the simple vapor method, cleaning results from the condensa-
tion of solvent vapors on the cool surface of the article; the dissolving and
flushing action of the condensate removes the soil. When the article reaches
the temperature of the solvent vapor, no more condensation (or cleansing)
occurs and the article is removed from the vapor zone. Other cleaning methods
involve various combinations of the simple vapor method with immersion and spray-
ind with liquid solvent.
Open top vapor degreasers utilize nonflammable solvent contained in the
lower area of the degreaser, referred to as the boiling sump. The solvent is
boiled to produce a vapor zone, the height of which is controlled by cooling
coils installed above the vapor zone. The "cold work" introduced into the
vapor space of the degreaser must be at a temperature lower than the vapor zone
in order to cause the solvent vapors to condense on the work surfaces and flush
the oil and other foreign matter off with the liquid condensate. The removed
material accumulates in the boiling sump and only the pure vapor comes in con-
tact with the work load. In either case, flushing is often followed by pure
solvent spray and/or liquid immersion. The cool, pure liquid solvent reduces
the temperature of the work surface below the vapor temperature, producing a
second vapor condensation flushing action on the work surfaces. When the work
pieces are removed from the degreaser, they should be clean, dry, and ready for
further processing.
3.1.2 Types of Open Top Vapor Degreasers
Open top vapor degreasers are most suitable in situations where the
work flow is variable or intermittent. Otherwise, a conveyorized degreaser
might be the equipment preferred. Essentially, there are three variations of
vapor degreasing: (1) straight vapor, (2) liquid immersion-vapor, and
(3) vapor-spray-vapor degreasing.
3.1-1
-------
o Straight Vapor: In this unit, the article to be cleaned is lowered
into the vapor zone and held there until it reaches the vapor temp-
erature, at which point vapors cease condensing on the article. It
is gently agitated to enhance drainage of trapped liquid solvent.
Then, it is brought into the freeboard area and allowed to dry for
a moment before being removed from the degreaser. Figure 3-1 is
a cut away sketch of a straight vapor degreaser. As with any open
top arrangement, the work to be cleaned may be lowered manually
or with an overhead hoist with hooks or long handle baskets. Hands
should never be placed below the vapor line.
o Liquid Immersion - Vapor: Immersion of the work in the hot or
boiling solvent is preferred; (i) for closely nested work, (ii) for
excessive soil levels (iii) for light gauge work, (iv) when ultra-
sonics is necessary, and (v) for parts with intricate patterns.
Figures 3-2 to 3-4 show various equipment configurations for this
technique. Typically, the work is lowered into the vapor zone for
a straight vapor rinse, then lowered into the liquid immersion
chamber to be rinsed. This will cool the work slightly. Then,
the work is raised into the vapor zone for a second vapor rinse.
The 2-compartment unit shown in Figure 3-3 may be operated in this
fashion or, if necessary for proper cleaning, the work may be
lowered directly into the boiling sump, then rinsed in the con-
densate reservoir. (Care should be taken not to drag dirty solvent
from the boiling liquid tank to the rinse tank). After the liquid
rinse the work is given a vapor rinse above the condensate reser-
voir. The reservoir is often heated to ensure that the liquid
rinse is warm. Similarly, the 3-compartment unit depicted in
Figure 3-4 may be outfitted to operate with two or three liquid
immersions.
o Vapor - Spray - Vapor: This is similar to straight vapor degreasing
except that as soon as the work is below the vapor level, it is
sprayed with cool condensate. After spraying is complete the work
should remain in the vapor zone until it reaches the vapor tempera-
ture and condensation has stopped. Figure 3-5 is a schematic of
a spray unit with an offset condenser. Spraying should be done
as far below the top of the vapor line as possible so that evapora-
tive losses due to spraying are minimized.
Some units, especially larger ones, are equipped with a lip exhaust. A
lip exhaust draws air laterally across the top of the degreaser and vents the
air directly to the roof or to a carbon adsorption unit. Figure 3-6 is a
schematic of one of these units. The primary purpose of a lip exhaust is to
limit worker exposure to solvent vapors.
Figures 3-7 through 3-9 are photographs of three variations of open top
vapor degreasers. The unit in Figure 3-8 relates directly to the schematic
in Figure 3-3. The physical dimensions of these units varies widely. For
example, the vapor-spray unit in Figure 3-7 commonly is purchased in several
sizes ranging from 2 feet wide by 4 feet long by 4 1/2 feet high to 4 feet
wide by 12 feet long by 9 1/2 feet high. Larger sizes are available on
special order.
3.1-2
-------
CONDENSING COILS
WATER SEPARATOR
DISTILLATE
HEAT EXCHANGER
CLEANOUT
DOOR
SOLVENT LEVEL
SIGHT GLASS
SAFETY
THERMOSTAT
FREEBOARD
WATER
JACKET
H CONDENSATE
TROUGH
HEATING
ELEMENTS
WORK REST AND
PROTECTIVE GRATE
\TEMPERATURE
INDICATOR
Figure 3-1. Single Compartment Vapor Degreaser
3.1-3
-------
WATER JACKET
CONDENSING COILS
CONDENSATE TROUGH
WATER
SEPARATOR
CONDENSATE RETURN
LIQUID IMMERSION
CHAMBER
STEAM/
-BOILING SUMP
Figure 3-2. Liquid-Vapor Degreaser
3.1-4
-------
FREE BOARD
BOILING SUMP-
CONDENSING COILS
WATER JACKET
CONDENSATE TROUGH
WATER SEPARATOR
CONDENSATE RESERVOIR
STEAM
Figure 3-3. Liquid-Liquid-Vapor Degreaser 2 Compartment
WORK FLOW
CONDENSING COILS
CONDENSATE TROUGH
HOT SOLVENT
RESERVOIR
WATER JACKET
•WATER
SEPARATOR
CONDENSATE RETURN
BOILING SUMP
STEAM
STEAM
WARM RINSE7 ^-OVERFLOW
Figure 3-4, Liquid-Liquid-Vapor Degreaser 3 Compartment
3.1-5
-------
FREE
BOARD
WATER
JACKET
FLEXIBLE HOSE
SPRAY LANCE
VAPOR LEVEL -.
STEAM
CONDENSING
COIL
^CONDENSATE
TROUGH
WATER
SEPARATOR
CONDENSATE
RESERVOIR
SPRAY
PUMP
BOILING SUMP
Figure 3-5. Offset Condenser Vapor-Spray-Vapor Degreaser
TO ATMOSPHERE
OR ADSORBER BLOWER
EXHAUST INLET
EXHAUST DUCT
CONDENSING UNIT
Figure 3-6. Degreaser with Lip Exhaust
3.1-6
-------
OJ
I-1
I
Figure 3-7. Perimeter Condensing Vapor-Spray-Vapor Degreaser
( Baron Blakeslee, Chicago, Illinois)
-------
Figure 3-3. Liquid-Liquid-Vapor Degreaser 2 Compartment
(Baron Blakeslee. Chicago, Illinois)
3.1-i
-------
Figure 3- 9.
Uquid-Liquid-Vapor Degreaser 3 CompartmentWith Automatic Dip
(Delta Industries, Santa Fe Springs, California. )
3.1-9
-------
The unit in Figure 3-9 is a 3 compartment degreaser that is outfitted
with an automatic hoist system. The work is loaded into a basket that is auto-
matically carried through the cleaning cycle. As pictured, the work is in
compartment #1. Note that as the mechanism moves the work from left to right
and back a horizontal cover is automatically opened and closed.
3.1.3 Operation of Degreaser Components
Open top vapor degreasers are relatively simple in design. Although
there are several different common configurations and optional features, they
share common design characteristics. Typical units, as shown in Figures 3-1
through 3-6, consist of a boiling sump, cooling coils, a work delivery system, a
vapor space above the boiling sump, a freeboard, safety thermostats, and a water
separator. Most units are equipped with a downtime cover to minimize solvent
loss when the degreaser is not in operation. Some units are equipped with a
liquid spray, ultrasonic cleaning mechanism, water jacket, or lip exhaust.
Brief descriptions of the primary components follow:
o Boiling Sump - The boiling (solvent) sump is located in the
bottom section of the degreaser and includes the heating coils
for vaporizing the liquid solvents. Steam, electricity, and gas
are the mediums normally used to heat the chamber. Steam is often
the most economical. Steam is usually supplied by use of a pipe
coil in the boiling sump although a steam jacket or panel may be
preferable in certain designs.
In those cases where electricity is the heating method of choice,
immersion type heaters should be installed on a sturdy support
within the boiling sump. Degreasers which are not expected to
accumulate metal fines or precipitate other insoluble solids may be
adequately heated by strip heaters fastened in close contact with
the underside of the sump.
If gas is used for heating, the burner is enclosed in an immersion
tube in the boiling sump. The combustion chamber must be of tight
construction and the gas flame's air supply should be designed so
that fresh air only is fed to the burner. Being a combustion
process an exhaust flue is required to vent the exhaust gases out
of the work area.
The boiling sump and heating elements (regardless of heating method)
should be accessible for cleaning and maintenance. The heating
elements usually are removable and access doors are often provided
for the sump, especially on larger units.
o Vapor Zone - The vapor zone is the volume of vapors above the boiling
liquid solvent up to the vapor/ambient air interface that occurs at
the cooling coils. This area in the degreaser is pure solvent vapor;
the solvent vapors are about 4 1/2 times as heavy as ambient air so
they are contained quite efficiently within the degreaser to form a
vapor zone in which the vapor degreasing actually occurs.
3.1-10
-------
o Freeboard - The upper body of the degreaser is extended above
the cooling coils to .provide a "seal" of stagnant air over the
vapor zone. This area is referred to as the freeboard and it
serves to reduce distrubances at the vapor/air interface thus
reducing solvent vapor emissions. It also serves as a dis-
engaging space for the traces of solvent which evaporate from
the work as it is withdrawn after cleaning.
o Cooling Coils - Cooling (condensing) coils are installed along
the inside surfaces of the degreaser; their location defines
the upper limit of the vapor space and the lower limit of the
freeboard. The coils consist of four or more pipe coils stacked
one above the other and located directly above a vapor condensate
trough. The cooling medium is normally tap or process water.
Usually, the water enters the bottom coil and exits at the top.
If the arrangement should be reversed, the bottom exit should
be connected to a standpipe at least as high as the condenser
so that the condenser will always stay full of water. Sometimes
the coils are set along only one side of the degreaser, as shown
in Figure 3-5.
o Water Separator - Water enters a degreaser from several sources;
i.e., condensation of atmospheric moisture oh condenser coils,
moisture on work pieces being processed, and steam or cooling
water leaks. Water forms a low boiling azeotrope with the sol-
vent and is vaporized. Most degreasers are equipped with a
water separator because uncontrolled water causes corrosion,
shortens solvent life, and increases the vaporization rate of
solvent. The condensed solvent-water mixture drops into the
condensate trough below the condenser coils and flows by gravity
to the separator.
o Piping and Sprays - There is a minimum amount of piping included
in the degreaser. Leaks should not be tolerated because they
represent a source of emission and a loss of valuable material.
Drain valves are generally found at the lowest point in the
tank. Piping that is under pressure, such as the spray line,
is a potential source of leaks. Sprays should be operated
within the vapor zone so as to not disturb the air/vapor inter-
face. Some designs spray the material in a contained chamber
within the degreaser. A spray safety switch is generally pro-
vided to shut off the spray pump when the vapor level drops
below the design level.
o Water Jacket - A water jacket, where applicable, is installed on
the exterior of the degreaser and consists of a box section to
contain cooling water circulating around the degreaser in the same
approximate area of the cooling coils. This jacket is sometimes
referred to as the freeboard cooler. Its function is to prevent
convection of solvent vapors up hot degreaser walls. In addition,
water jackets may reduce "sidewall radiation" from hot freeboard
walls. This heat radiation can increase air turbulence and thus
disturb the cold air blanket in the freeboard area. Water jackets
are sometimes used in lieu of cooling coils in smaller units.
Water jackets and cooling coils should not be confused with refri-
gerated chillers. Chillers are sometimes used in addition to these
units in order to increase vapor control efficiency.
3.1-11
-------
o Covers - An automatic or manual cover should be installed on open
top vapor degreasers. The use of such covers reduces solvent losses
during idling and downtime. A simple lid type cover is effective
if utilized by operating personnel. Newer units often are equipped
with mechanisms that are more easy to use, and hence more frequently
used. The more popular manual designs open and close in a horizontal
motion, so that the air/vapor interface disturbance is minimized.
These types of covers include roll type plastic covers, canvas curtains
and quillotine covers. It is usually advantageous on larger open top
vapor degreasers to power the cover. This may be done pneumatically
or electrically, usually by manual control with an automatic cutoff.
The most advanced covering systems are automated in coordination with
the hoist or conveyor. The cover can be designed so it will close
while the parts are being cleaned and dried. Thus, the cover is
open for only a short period of time when the parts are actually
entering or exiting the degreaser.
o Safety Switches - A variety of safety switches are available to
prevent emissions or damage to the equipment during a malfunction.
(1) The most important safety switch is the vapor level control
thermostat. This device turns off the sump heat if the vapor zone
rises above the design level. When hot vapors are sensed above the
cooling coils the sump heater is turned off, thus minimizing solvent
vapor losses. (2) The condenser water flow switch and thermostat
turns off the sump heat when either the condenser water stops circu-
lating or the condenser water becomes warmer than specified. (3) The
boiling point in the sump increases as the solvent becomes contami-
nated with oils, grease and other materials. To prevent the sump
from becoming too hot, thus causing solvent decomposition, the sump
thermostat cuts off the heat when the sump temperature rises signi-
ficantly above the solvent's boiling point. (4) The sump can be-
come too hot also if the liquid level drops and exposes the heating
elements. Thus, some units are equipped with a solvent level control
that cuts off the heat if the liquid level in the boiling sump drops
down to the level of the sump heater coils. (5) Spraying above the
vapor line can cause excessive emissions, so a few units are equipped
with a spray safety switch that turns off the spray pump if the vapor
level drops below a specified level.
As a minimum, the vapor level control thermostat should be of the
manual reset type. Some manufacturers install manual reset switches
for all of the safety switches they install on a unit.
o Water Regulating Valve - To minimize water consumption, some units
are equipped with a water regulating valve installed at the water
outlet of the cooling coils. A constant temperature is automatically
maintained at the outlet of the coils by the valve's temperature bulb.
The valve opens on temperature rise, closes on temperature drop.
o Ultrasonics - If parts are immersed in the liquid solvent, cleaning
may be enhanced by vibrating the solvent with high frequency sound
waves. To optimize cavitation at the surface of the work the solvents
need to be heated to specific temperatures. Cavitation is the implo-
sion of microscopic vapor cavities within the liquid solvent.
3.1-12
-------
3.2 ATMOSPHERIC EMISSIONS
3.2.1 Emission Points
There are several means by which organic solvent vapors can be emitted
to the atmosphere in an open top vapor degreaser. These are identified in
Figure 3-10. In general, open top units are not hooded or vented to the out-
side. Thus, an obvious emission point is the direct diffusion and convection
of vapors from the vapor zone to the atmosphere (Location 1). If a lip
exhaust is installed some of these vapors can be directed to a roof vent
(Location 2). If not properly designed, these systems can actually increase
solvent evaporation, especially if the exhaust rate is excessive, causing
disruption of the air/vapor interface. The use of lip (or lateral) exhausts
is usually limited to larger than average degreasers where the primary objec-
tive is to limit worker exposure to solvent vapors. A rule of thumb used by
degreaser and control systems manufacturers is to set the exhaust rate at 50
cubic feet per minute per square foot of degreaser opening. If this exhaust
rate is not adequate to protect the workers, higher rates may be encountered.
Carry-out emissions result from solvent that has condensed on the work
and has not fully evaporated before being removed from the degreaser (Loca-
tion 3). Also, solvent vapors may be entrained by the motion of removing
the work from the vapor zone or by convection due to the hot work heating
the solvent laden air as it is removed from the vapor zone. Porous or
adsorbant materials such as cloth, leather, wood or rope will adsorb and
trap condensed solvent and thus such materials should never enter a degreaser.
As the solvent material is spent and itself becomes contaminated with
impurities its usefulness decreases. To reduce the volume of waste material
some degreasers are used as a simple still during downtime where the solvent
in the sump is boiled off as much as feasible and the pure condensed vapors
are piped off to a storage tank, rather than back to the sump. Other
degreasers, especially the larger ones, may be used with an external still
that may run on a continuous or batch basis. Nevertheless, a significant
volume of waste material will remain to be disposed of and depending on the
method of disposal, waste solvents may enter the atmosphere (Location 4).
Fugitive emissions can occur at any of the piping connection or pump
seals that may have loosened, or become worn or corroded (Location 5).
These emission points are usually eliminated fairly quickly because they are
detectable by visual observation and represent a correctable loss of valuable
material, and create a potentially unhealthy work environment.
3.2-1
-------
POTENTIAL
ADSORBER
u>
N3
I
LIP TOP
EXHAUST
RETRACTABLE
COVER
DIFFUSION AND
CONVECTION
CONDENSER
COILS
Figure 3-10. Open Top Degreaser Emission Points
-------
3.2.2 Parameters Affecting Rate of VOC Emissions
The rate of vapor emissions emanating from the various points pre-
viously discussed is dependent on a variety of operating and design para-
meters. Emissions can be minimized by attempting to achieve certain optimum
conditions; however, it is important to understand the cause and effect
relationsiip. The following parameters significantly affect VOC emissions
from open top vapor degreasers:
o Freeboard Ratio - The freeboard ratio is the ratio of the freeboard
height to the width (not the length) of the degreaser. Manufacturers
of degreasers generally size the equipment so that this ratio is at
least 0.5 for the higher boiling solvents. For solvents with lower
boiling points, such as methylene chloride and trichlorotrifluoroe-
thane, this ratio should be at least 0.75.
o Drafts - A fan or other air moving devices located in the work area
near the degreaser can cause a draft to enter the freeboard area of
the degreaser housing, thereby upsetting the interface and drawing
vapors into the ambient air.
o Type of Work Load - Atmospheric emissions increase when the parts
being processed in the degreaser contain numerous pockets or liquid
traps that allow liquids to be carried from the degreaser chamber.
o Size of Work Load - If the cross-sectional area of the work is sub-
stantial compared to the cross-sectional area of the vapor chamber,
moving the work in and out of the degreaser will have a piston
effect on the surrounding vapors; the resulting turbulence will
cause excessive emissions.
° Mass of Work Load - If the work load is especially massive the heat
required to bring the work to vapor temperature will be excessive.
This will cause the vapor zone to collapse resulting in turbulence
that will increase emissions.
o Solvent Heat Input - Once the solvent's boiling temperature has been
achieved, increasing the heat input to the solvent will increase
the rate of solvent vaporization. If continued, the cool air
blanket generated by the condenser coils may not be sufficient to
retain the increased vapors and breakthrough could occur, resulting
in greater emissions.
o Temperature and Flow Rate of the Cooling Water - The function of a
condensing coil is to limit the upper level of the vapor zone. A
condenser consisting of a coil of pipe through which cooling water
flows, creates a blanket of cool air. The flow rate and temperature
of the water affect the efficiency of a given set of coils with a
given heat input rate. Increasing flow increases efficiency.
Decreasing the temperature of the water will also increase the
efficiency of the coils in supporting the vapor layer.
3.2-3
-------
Work Rate - Moving the work into and out of the degreaser creates
turbulence that will result in the emission of vapors. Turbulence
and the resulting emissions increase as the speed of the work in-
creases .
Location of Spraying - If spraying is conducted in a manner that
disrupts the vapor/air interface, emissions will increase. Spray-
ing should be done below the vapor line; the spray should never
be pointed to allow liquid to be sprayed above the vapor line.
Water in the Solvent - If water is allowed to accumulate in the boil-
ing sump emissions may be increased in three ways: (i) the water/
solvent vapor mixture has a lower density than pure solvent vapor and
thus has a greater tendency to be lost by diffusion, (ii) water com-
bines with the solvent to form a low boiling azeotrope that results
in a higher vaporization rate, and (iii) water is corrosive to de-
greaser surfaces and piping, thus making leaks a serious problem.
Water has a tendency to form acidic by-products with certain solvents,
especially 1,1,1 - trichloroethane and methylene chloride, further
exacerbating the corrosion problem.
Covers - The use of a cover during idle and down time virtually
eliminates diffusion losses during these periods.
Drying Time - After the work has been removed from the vapor zone
it may carry some condensed solvent out of the degreaser. To
minimize these emissions the work should be allowed to dry for a
brief time (about 15 seconds) in the freeboard area. Note, however,
that when the hot part rests just above the vapor level, it will
cause solvent laden air to heat up and rise, so the drying time
should not become excessive.
Lip Exhaust - If the degreaser is equipped with a lip exhaust, the
ventilation rate should not be excessive; otherwise, the exhaust
system may disrupt the air/vapor interface and actually increase
emissions.
3.2-4
-------
3.3 EMISSION CONTROL METHODS
The EPA Control Technology Guideline document for solvent metal cleaning
identifies a number of control strategies for reducing volatile organic emis-
sions from open top vapor degreasers. These form the basis for defining RACT
for these degreasers and should therefore be the focal point of a field inves-
tigation. The CTG document suggests two alternative control schemes. Level A
represents a relatively low efficiency system consisting primarily of operating
procedures and has an estimated efficiency of 45 (+15) percent. Level B
consists of Level A plus additional control and has a control efficiency es-
timated at 60 (+15) percent. These control methods are presented in Table 3-1.
EPA's policy regarding the application of these control levels is discussed in
Chapter 1. EPA suggests that open top vapor degreasers with an open area
of less than one square meter be exempt from the application of refrigerated
chillers or carbon adsorbers because these devices would not be cost effective
on such snail units.
The safety switches and thermostat recommended in Control System B are
the spray safety switch, the condenser flow switch and thermostat. The vapor
level thermostat is not included because it is already required by OSHA on
"open surface vapor degreasing tanks". The sump thermostat and solvent level
control discussed in Section 3.1.3 are used primarily to prevent solvent degra-
dation and protection of the equipment rather than to prevent solvent emissions.
Refrigerated chillers should not be confused with the condenser coils
or water jacket; rather, the chillers are an optional, additional control device
designed to minimize solvent losses. The refrigerated chiller consists of a
second set of condenser coils located slightly above the primary coils.
Figure 3-11 depicts a unit with finned chiller coils. The function of the
primary coils remains as in units without freeboard chillers, i.e. to control
the upper limit of the vapor zone. The refrigerated freeboard chiller creates
a sharper temperature gradient than would otherwise exist. The resulting cold
air blanket reduces diffusion losses and the stable inversion layer created
by the increased temperature gradient decreases upward convection of solvent
laden air.
Two types of chiller designs are commercially available; one that operates
below 0°C and one that operates above that temperature. Most manufacturers of
degreasing equipment offer both types, although there is a patent* on the sub-
zero design.
*U.S. Patent 3,375,177 issued to Autosonics, Inc., March 26, 1968
3.3-1
-------
TABLE 3-1
COMPLETE CONTROL SYSTEMS FOR OPEN TOP VAPOR DEGREASERS
Control System A
Control Equipment:
1. Cover that can be opened and closed easily without disturbing the vapor zone.
Operating Requirements:
1. Keep cover closed at all times except when processing work loads through
the degreaser.
2. Minimize solvent carry-out by the following measures:
a. Rack parts to allow full drainage.
b. Move parts in and out of the degreaser at less than 3.3 m/sec.(ll ft/min).
c. Degrease the work load in the vapor zone at least 30 sec. or until
condensation ceases.
d. Tip out any pools of solvent on the cleaned parts before removal.
e. Allow parts to dry within the degreaser for at least 15 sec. or until
visually dry.
3. Do not degrease porous or absorbent materials, such as cloth, leather, wood
or rope.
4. Work loads should not occupy more than half of the degreaser's open top area.
5. The vapor level should not drop more than 10 cm (4 in.) when the work load
enters the vapor zone.
6. Never spray above the vapor level.
7. Repair solvent leaks immediately, or shutdown the degreaser.
8. Do not dispose of waste solvent or transfer it to another party such that
greater than 20 percent of the waste (by weight) will evaporate into the
atmosphere. Store waste solvent only in closed containers.
9. Exhaust ventilation should not exceed 20 m /min. per m (65 cfm per ft )
of degreaser open area, unless necessary to meet OSHA requirements. Ventilation
fans should not be used near the degreaser opening.
10. Water should not be visually detectable in solvent exiting the water separator.
Control System B
Control Equipment:
1. Cover (same as in system A).
2. Safety switches.
a. Condenser flow switch and thermostat - (shuts off sump neat if condenser
coolant is either not circulating or too warm).
b. Spray safety switch - (shuts off spray pump if the vapor level drops
excessively, about 10 cm (4 in).
3. Major Control Device:
Either: a. Freeboard ratio greater than or equal to 0.75, and if the degreaser
opening is >lm (10 ft ), the cover must be powered,
b. Refrigerated chiller,
c. Enclosed design (cover or door opens only when the dry part is
actually entering or exiting the degreaser), 2
d. Carbon adsorption system, with ventilation >15 nrVmin per m
(50 cfm/ft2) of air/vapor area (when cover is open), and exhausting
<25 ppm solvent averaged over one complete adsorption cycle, or
e. Control system, demonstrated to have control efficiency, equiva-
lent to or better than any of the above.
4. Permanent, conspicuous label, summarizing operating procedures #1 to #6.
Operating Requirements:
Same as in System A
3.3-2
-------
The recommended operating temperature for below freezing chillers is
-30 to -25°C. The cold coils attract moisture as does a dehumidifier. There-
fore, the designs include a defrost cycle to remove frost from the coils and
restore heat exchange efficiency. The defrost cycle operates approximately
hourly, requiring only a few minutes to melt the accumulated ice and slush,
which is collected in the condensate trough and poured through the water
separator. Water contamination of the solvent can have an adverse affect on
water soluable stabilizer systems and can contribute to equipment corrosion.
Therefore, on some units, the material condensed from the chiller coils may
be diverted to a different water separater.
The operating temperature of above freezing chillers should not exceed
5°C. These units are normally designed to achieve a minimum of 500 Btu/hr
cooling capacity per foot of air/vapor interface perimeter. The sub-freezing
units are normally designed in the range of 200-600 Btu/hr per foot of peri-
meter, depending on the width of the degreaser.
3.3-3
-------
CHILLER
PRIMARY COILS
FREEBOARD
WATER JACKET
Figure 3-11. Refrigerated Freeboard Chiller
3.3-4
-------
3.4 INSPECTION PROCEDURES
The following paragraphs discuss two types of inspections: (1) field
review and (2) office review. Source sampling, still another form of inspec-
tion, will be discussed in Chapter 5.
Field investigations range from brief plant visits to thorough inspections
and testing programs that produce a complete data base for enforcement proceed-
ings. Office reviews rely on the source to furnish information through written
material such as permit applications and responses to Section 114 inquiries.
This approach may require less time and manpower but the resulting data base
is generally less complete. Office reviews, however, provide a useful screen-
ing tool in those cases where there is a large number of potential violators.
3.4.1 Field Inspections
After becoming familiar with the plant and its facilities, the inspector
should request that the appropriate company official give him information from
company records that will allow the inspector to begin completing the worksheets
shown in Figure 3-12. The data may also be available from permit applications.
The worksheet divides the required data into two categories: control equip-
ment and operating requirements. It also provides the RACT requirements for
each category with a suggested inspection procedure. With such information,
direct comparisons can be made between the RACT requirements and observed
practices.
Generally, the inspector would next request the company's assistance in
conducting a full inspection of the facility in order to verify the actual
operating conditions. This inspection may take several hours depending on the
number and types of open top vapor degreasers. The inspector must collect
information that will allow him to complete the inspection worksheet. All
field data, such as temperature of the coolant, exhaust flow rate, etc., should
be observed and verified by the air pollution inspector. For equipment that
is operating, the inspector must be prepared to collect this data with his own
resources.
This information will be compared to the data given by the company official,
and the total data base will be compared to the RACT requirements for control
equipment and operating conditions to determine if a violation exists. At that
time, a reinspection date should be established if it is determined that the
source is not in compliance.
3.4-1
-------
FIGURE 3-12
EXAMPLE WORKSHEET FOR FIELD INSPECTION OF
OPEN TOP VAPOR DEGREASERS
1. BUSINESS LICENSE NAME OF CORPORATION, COMPANY, OR INDIVIDUAL OWNER OR GOVERNMENTAL AGENCY:
2a. MAILING ADDRESS:
2b. PLANT ADDRESS WHERE THIS DEGREASER IS LOCATED:
3. SOURCE NO. (PERMIT NUMBER, NEDS ID, ETC.)
4. NAME AND TITLE OF COMPANY REPRESENTATIVE:
5. TELEPHONE NO.:
6. NAME OF OFFICIAL CONDUCTING INSPECTION:
7. DEGREASER
MANUFACTURER:
MODEL NO.
INSIDE DIMENSIONS OF TANK (FT.):_
WIDE X
_SERIAL N0._
LONG X
DEEP
8. TITLE AND CODE NUMBERS OF DRAWINGS, SPECIFICATIONS, STANDARDS, CODES, PROCEDURES AND DOCUMENTS USED WITH
THE INSPECTION
9. TYPE OF SOLVENTS IN USE (SPECIFIC NAME AND MANUFACTURER):
INSPECTION OBSERVATIONS
RACT REQUIREMENTS
SUGGESTED INSPECTION
PROCEDURE
FIELD
OBSERVATIONS
CONTROL EQUIPMENT
1. Lid
Observe if a lid is in-
stalled and if it is used
during idling and downtime.
Observe if opening and
closing the lid disturbs
the vapor zone.
2. Safety Switches
a. Condenser flow
switch & thermo-
stat
Confirm that the switch
and thermostat have been
installed.
If available, check read-
ings of flow and tempera-
ture indicators. For high
boiling solvents, the temp-
erature should be about 8°
to 11°C (15° to 20°F) above
dewpoint of surrounding
atmosphere or 32° to A6°C
(90° to 115°F). For low
boiling solvents (methy-
lene chloride and fluoro-
carbon 113) the exit temp-
erature should be less than
29°C (85°F). Many installa-
tions may not have a temper-
ature indicator at the cool-
ing coil exit. A rough es-
timate of the temperature
may be made if a bleed valve
is available at the exit end
of the coils. Bleed a sample
of coolant into a small vessel
and measure the temperature
with a portable thermometer.
If plant is agreeable,
interrupt flow of coolant
and determine if switch is
tripped.
3.4-2
-------
FIGURE 3-12
(Continued)
RACT REQUIREMENTS
SUGGESTED INSPECTION
PROCEDURE
FIELD
OBSERVATIONS
b.
Spray safety
switch
Confirm that the switch
has been installed.
3. Major Control Devices
a. Freeboard ratio
greater than 0.75.
b. If the degreaser
area is greater
than 1.0m2 the
cover must be
powered.
c. Refrigerated
Chiller
d. Enclosed Design
Measure the height of the
freeboard and the width of
the tank; calculate the
ratio.
(Measurements usually can
be made externally to
avoid creating emissions
and breathing solvent
vapors. Otherwise, obtain
the measurements from
shop drawings). Measure
the length of the tank and
calculate the degreaser
area. Observe if the
cover is powered.
Unless observed during
the defrost cycle, sub-
zero chillers should be
coated with frost or
slush. The indicated
temperature of the coolant
should not exceed -25°C
(-13°F). Do not attempt
to extract a sample of
coolant from a refrigerated
chiller.
For above freezing chillers
the coolant temperature
should not exceed 5°C
(40°F).
Determine the cooling capacity
from the design specifications.
oo For subzero
chillers the
minimum cooling
capacity should be
as follows for each
degreaser width:
(The cooling units
are Btu's per hour
per foot of perimeter.)
<3.5 ft - 200
>3.5 ft - 300
>6 ft - 400
>8 ft - 500
>10 ft - 600
oo For above freezing
chillers the cooling
capacity should be
at least 500 Btu/hr
per foot of perimeter.
Observe that the cover or
doors are open only when
the dry part is entering
or exiting the degreaser.
3.4-3
-------
FIGURE 3-12
RACT REQUIREMENTS
(Continued)
SUGGESTED INSPECTION
PROCEDURE
FIELD
OBSERVATIONS
e. Carbon Adsorber
o If the degreaser is equipped
with an adsorber solvent odors
should not be detectable on
the roof downwind from the
stack.
o See the source testing
section in this manual.
OPERATING REQUIREMENTS
1. Keep cover closed
except while process-
ing work loads.
o Observe the operation.
2. Minimize solvent carry-
out by the following
measures:
a. Rack parts to
allow full drain-
age.
b. Move parts in
and out of de-
greaser at less
than 3.3 m/sec
(11 ft/min).
c. Degrease parts for
at least 30
seconds or until
condensation stops.
d. Tip out pools of
solvent on the
cleaned parts be-
fore removal.
e. Allow parts to
dry within the
degreaser for at
least IS seconds
or until visually
dry.
o Observe how the parts are
racked.
o Using a stopwatch, time
the vertical movement of
parts over a measured
distance.
o Observe this operation
and time it if necessary.
o Observe this operation.
o Observe this operation,
time it if necessary.
3.
Do not degrease porous
or absorbant materials.
Note the nature of the
materials being cleaned.
Baskets should not have
rope or leather handles.
4. Work loads should not
occupy more than half
of the degreasers open
top area.
0 Observe the size of the
work load. Measure it if
necessary and compare it
to the open top area.
The vapor level should
not drop more than 10 cm
(4 inches) when the
work load enters the
vapor zone.
Observe this operation and
estimate the drop in the
vapor level.
6.
Never spray above the
vapor line.
° Observe this operation.
7. Repair solvent leaks
immediately or shut
down the operation.
0 Look for leaks around the
degreaser. Note especially
the solvent spray pump and
line, piping, the external
sump drain valve (if so
equipped) and the water
separator.
3.4-4
-------
FIGURE 3-12
(Continued)
RACT REQUIREMENTS
8. Do not dispose of
waste solvent or
transfer it to
another party such
that greater than
20 percent of the
waste (by weight)
can evaporate
into atmosphere.
Store waste solvent
only in covered con-
tainers.
9. a. Exhaust ventilation
should not exceed
20m3 /min per m2
(65 cfm per ft2) of
degreaser open area
unless necessary to
meet OSHA requirements.
b. Ventilation fans
should not be
used near degreaser
opening.
10. Water should not be
visually detectable
in solvent exiting
the water separator.
11. Permanent, conspicuous
label, summarizing
operating procedures
#1 to #6 above.
SUGGESTED INSPECTION
PROCEDURE
° Determine if source has
inhouse reclamation
facilities (i.e. still)
or a service contract
with a solvent reclamation
firm.
o Confirm that storage is
done with covered con-
tainers by visual inspec-
tion. Note whether con-
tainers leak.
° Determine the air handling
capacity of the fan,
-or-
If sampling ports are
available, the velocity of
the exhaust gases may be
measured with a swinging
vane velocity meter. Also
determine the cross-sectional
area of the duct, then cal-
culate the cfm.
o After the air volume is
determined from either of
the above methods, obtain
the area of the degreaser
opening and calculate the
cfm per square foot of
degreaser opening.
o Note the location of ven-
tilation fans near the
degreaser .
o This solvent Is normally
returned to the degreaser
sump, or if so equipped,
to the warm rinse tank.
This solvent should be clear.
o Confirm the presence of
this label.
FIELD
OBSERVATIONS
3.4-5
-------
3.4.2 Record .Review
Determining compliance of open top vapor degreasers through field inspec-
tions and monitoring is expensive and time consuming due to the large number of
degreasers in use. It requires a great deal of manpower and tends to limit the
number of sources that can be reviewed in a given year. The review of company-
furnished records through questionnaires or letter requests may provide a
viable alternative to field inspections and source monitoring activities for
compliance determination. At minimum, this approach should be considered as
a screening tool to identify candidate sources for comprehensive field inspec-
tions, thereby increasing the effectiveness of the available resources.
This discussion outlines several procedures that may be used when imple-
menting a record review. Information will be required from the plant concerning
the design and operation and maintenance of the equipment.
3.4.2.1 Review of Design, Operation, and Maintenance Data
The first requirement of this procedure is the development of standard
questionnaires that can be sent out as part of a Section 114 request to the
applicable sources. The type of information required is similar to what is
identified on the inspection forms illustrated in Figure 3-12. It is important
that the source understand what is being requested because the entire process
of making compliance judgments using this procedure is highly dependent on
the reliability of the information being furnished.
An example questionnaire is provided as Figure 3-13 and should be used
as a guide only. It is suggested that the agency develop its own form which
is specific to their program. For example, a screening program designed to
identify major emitters may only require key data, while a more extensive
request is necessary if compliance determinations are to be attempted. Three
types of data are suggested for review: control equipment information, opera-
tional information, and maintenance records. The design data should be readily
available, while operational and maintenance may require the source to create
a special logging system in order to comply with the agency's request.
Criteria for review of the data should be established prior to finalizing
the questionnaire. Obviously the criteria will address the overall objectives
of the review program (e.g., screening program or compliance determination).
In general, however, the design data should be compared to the original construc-
tion permit and design specifications and be at least as stringent as RACT.
3.4-6
-------
FIGURE 3-13
U.S. ENVIRONMENTAL PROTECTION AGENCY
OPEN TOP VAPOR
DEGREASER SUMMARY
ONE COPY OF THIS FORM MUST BE FILLED OUT FOR EACH DEGREASER
1. BUSINESS LICENSE NAME OF CORPORATION, COMPANY, OR INDIVIDUAL OWNER OR GOVERNMENTAL AGENCY:
2a. MAILING ADDRESS:
2b. PLANT ADDRESS WHERE THIS DEGREASER IS LOCATED:
3. SOURCE NO. (PERMIT NUMBER, NEDS ID, ETC.):
4. DEGREASER
MANUFACTURER:
MODEL NO.
SERIAL NO.
INSIDE DIMENSIONS OF TANK (FT.):
WIDE X
LONG X
DEEP
CONVEYORIZED: YES [ | NO \ \ IF YES, GIVE CONVEYOR SPEED: fps
TYPE OF DECREASING: COLD SOLVENT CLEANING | [ VAPOR DECREASING | |
5. TYPE OF VAPOR LEVEL CONTROLS:
THERMOSTAT | | CONDENSING COIL | I CHILLED WATER OR REFRIGERANT | [ NONE
6. METHOD OF HEATING DEGREASER:
GAS | t ELECTRIC | | STEAM | | Btu/hr._
OR KW
7. CLEANING ACTION:
SONIC | [ IMMERSION IN LIQUID 1 | MECHANICAL MIXING | f VAPOR CONDENSATION I )
SPRAY | | SPRAY PUMP H.P. OTHER] [
8. TANK COVER:
AUTOMATIC COVER | | MANUAL COVER | I NO COVER( |
TANK COVERED WHEN NOT IN USE: YES | | NO | [
9. QUANTITY OF SOLVENTS USED:
(Do not include quantities of used solvent sent back to supplier.)
a. CARBON TETRACHLORIDE
b. PERCHLOROETHYLENE
c. METHYLENE CHLORIDE
d. 1,1,1 -TRICHLOROETHANE
e. TRICHLOROETHYLENE
f. OTHER (IDENTIFY)
_55-GALLON DRUMS PER MONTH
_55-GALLON DRUMS PER MONTH
_55-GALLON DRUMS PBR MONTH
J5-GALLON DRUMS PER MONTH
_55-GALLON DRUMS PER MONTH
55-GALLON DRUMS PER MONTH
10. OPERATING SCHEDULE:
HOURS /DAY
DAYS/WEEK
WEEKS/YEAR
11. DESCRIBE METHOD FOR DISPOSING OF SPENT SOLVENT:
3.4-7
-------
This would include such items as exhaust ventilation rates, types of safety
switches, and cover design. Operational information should be compared to
operating permits and operational specifications defined as RACT in the CTG.
These parameters would include the use of powered or unpowered covers, the
quantity and type of parts being cleaned, the method of waste solvent disposal,
and the actual ventilation rates. Maintenance records should include repair
or replacement records, recalibration schedule of temperature sensors, and
some statement as to the general condition of the equipment.
3.4.2.2 Review Waste Solvent Disposal Procedures
A description of waste solvent disposal methods used by the source must
be requested in the questionnaire initiated by the agency (example shown in
Figure 3-13). A comparison should be made with the RACT operating requirements
("not greater than 20 percent can evaporate into the atmosphere"), and other
acceptable practices which are readily available.
On larger open top vapor degreasers where greater quantities of solvent
are used, it becomes economical to install a solvent distillation still for
solvent reclamation. On installations of this type, both the sludge and sol-
vent are pumped to the solvent still where the solvent is reclaimed. The
liquid is heated to its vaporization temperature and the resulting vapors flow
into a chilled condensing chamber where the vapors condense back to liquid.
The liquid is then circulated back to the degreaser for further use. In this
type of operation, only make-up liquid solvent is added, as needed. If
properly designed and operated, the still should produce a sludge that contains
less than 20% solvent by weight. Disposal of the sludge may be subject to
hazardous waste disposal regulations. EPA has proposed regulations governing
the disposal of such material in the Federal Register at 43FR58946 (December 18,
1978).
There are alternative approaches to an inhouse still, such as service con-
tracts with outside agents which may be more attractive to the source and
will also meet the RACT requirements.
3.4-8
-------
CHAPTER 4
CONVEYORIZED DEGREASERS
4.1 PROCESS DESCRIPTION
4.1.1 Unit Operation
Conveyor operated solvent degreasers provide an efficient and econo-
mical method for preparing clean, dry articles for subsequent finishing or
fabricating. There are several types of conveyorized degreasers and each can
operate with either cold or vaporized solvents. The basic steps found in the
typical conveyorized vapor degreaser include a vapor rinse upon entry to the
degreaser vapor space section, liquid immersion, liquid spray, vapor rinse,
and, finally, a slow withdrawal through a cold air space drying area.
A nonflammable solvent contained in the lower area of the de-
greaser, referred to as the boiling sump, is boiled to produce a vapor zone,
the height of which is controlled by cooling coils installed above the vapor
zone. The "cold work" introduced into the vapor space of the degreaser must
be at a temperature lower than the vapor zone, in order to cause the solvent
vapors to condense on the work surfaces and flush the oil and other foreign
matter off with the liquid condensate. The removed material accumulates in
the boiling sump and only the pure vapor comes in contact with the work load.
Vapor flushing is followed by pure solvent spray and/or liquid immersion.
The cool, pure solvent reduces the temperature of the work surface below the
vapor temperature, producing a second vapor condensation flushing action on
the work surfaces. When the work pieces are removed from the vapor zone,
they should be clean, dry, and ready for further processing.
A well-operated conveyorized vapor degreaser should provide the re-
quired cleansing action and confine the solvent and solvent vapors, thereby
maintaining a healthful working environment.
4.1.2 Types of Conveyorized Degreasers
Conveyorized degreasers are generally large, automatic units de-
signed to handle a high volume of work in either a straight-through process
or a return type process in which the work pieces enter and leave the
degreaser unit from the same end. Their use minimizes the human element and
produces consistently high quality cleaning with minimum solvent losses. As
indicated earlier, there are several basic designs which are termed conveyor-
ized degreasers: gyro, vibra, monorail, cross-rod, mesh belt and strip
cleaners. Figures 4-1 to 4-4 present a sketch of each design (with the excep-
4.1-1
-------
WORK BASKET
B°N-ING CHAMBER
GEAR TO
TUMBLE BASKETS
Figure 4-]a.
Degreaser
ASCENDING
VIBRATING
TROUGH '
WORKLOAD
ENTRY CHUTE
STEAM COILS
WORKLOAD
CHUTE RGI
iAj-^-wga
CONDENSERS
COUNTERROW WASH
4.1-2
-------
CONVEYOR
PATH
-p-
l->
SPRAY
PUMP
BOILING
CHAMBER J
WATER
JACKET
Figure 4-2. Monorail Degreaser
-------
CROSS-RODS
4>
h-1
CONVEYOR
PATH
CHAIN
SUPPORTS
WORK
BASKET
WATER
JACKET
BOILING CHAMBER
Figure 4-3. Cross-Rod Degreaser
-------
CONVEYOR
PATH
H-
I
BOILING
CHAMBER
MESH
BELT
Figure 4-4. Mesh Belt Conveyorized Degreaser
-------
tion of the strip cleaner type). A brief discussion of the rationale for
each system follows:
° Gyro (ferris wheel) type degreasers permit the operator to load
and unload the baskets from one work station. The design is simi-
lar to the cross-rod degreaser. It is one of the smallest con-
veyorized degreasers available.
o Vibra type degreasers are used for high production rate applica-
tions where the work pieces are small. The work piece is dipped
into solvent, and rises on a spiral vibrating elevator through a
counter-flow rinsing action of clean solvent vapor. Cleaning
action is accomplished by the combination of vibration, solvent
dip, and solvent vapor condensation.
o Monorail conveyor systems are used for high production of stan-
dardized work pieces and are generally found in facilities that
use monorail systems to transport materials within the plant.
The monorail can be a straight through type, carrying parts in
one side and out the other, or can turn 180° and exit the material
through a duct that is parallel and adjacent to the entrance.
o Cross-rod conveyorized units are generally used for processing
small or irregular parts. A rod placed between two power-driven
chains carries parts within suspended pendant baskets or per-
forated cylinders. The cylinders are rotated to provide the
tumbling action required to clean and drain the crevices in
the work pieces. The pendant baskets do not rotate and are
used to carry small parts that do not require this action for
cleaning and draining.
o Mesh belt and strip cleaner degreasers are similar in design;
however, the mesh belt degreaser carries the material to be
cleaned while the other draws the material through. The latter
design is used for sheet metal products. A continuous strip of
material is drawn through tha unit for cleaning prior to coating
or fabrication processes. Mesh belt degreasers are used for
smaller parts and allow for rapid loading and unloading of
material.
4.1.3 Operation of Degreaser Components
Continuous conveyorized degreaser systems are straight forward in
design. Although there are several types of conveyorized degreasers, they
share common design characteristics. A typical unit, shown in Figure 4-5,
consists of several components; a conveyor work piece transfer system to
carry the work pieces through the degreaser, a bottom sludge sump, a solvent
boiling sump with heating coils, and a vapor space above the boiling sump.
Over the solvent vapor space and around the inner-periphery of the degreaser
housing are cooling coils designed to maintain a temperature that will con-
dense the vapors. Upon return to a liquid btate, the solvent flows down to
the boiling sump. The freeboard area above the primary condensing coils is
designed to be of sufficient height to retard convection and diffusion losses
'4.1-6
-------
HOOD
PARIS
BASKET
CROSSBAR
CONVEYOR
CONDENSING
fT~ COILS
/WATER
SEPARATOR
CONDENSATE
RETURN
BOILING
SUMP
Z
STEAM
L
OVERFLOW
Z
STEAM
Figure 4-5. Liquid-Liquid-Vapor Cross-Rod Degreaser
.1-7
-------
to the atmosphere. Brief descriptions of the primary components are provided
to familiarize the inspector with their operation.
o Hood and Exhaust System - Unlike cold cleaners or open top
cleaners, conveyorized degreasers do not require access to the
product for manual handling. Therefore, they are generally
enclosed units with a hood and exhaust system. The ventilation
rate is established at a level sufficient to remove vapors from
the enclosures; however, excessive rates may induce greater
emissions.
o Solvent Sump and Sludge Sump - The solvent sump is in the bottom
section of the conveyorized degreaser and includes heating coils
for vaporizing the liquid solvents. The solvent sump is also
referred to as the solvent boiling area or chamber. The solvent
sump includes solvent storage, a liquid level sight glass, heat-
ing coils and elements, sump safety thermostat controls, and
an automatic shut-down switch. The primary adjustment affecting
the bath evaporation rate is the heating and cooling balance.
The heating rate must be sufficient to maintain the desired vapor
level as cold parts enter the vapor zone. The vapor level control
thermostat will sense hot vapors rising above the design opera-
ting level and turn off the sump heater.
The sludge sump is usually located in the lower section of the
solvent sump. It generally contains either a cleanout drain valve
or a cleanout door.
o Work Opening - Work openings include the entry and discharge
points. The work entry must be adequate for the work being pro-
cessed but should be kept to a minimum to control vapor loss.
Drying tunnels as shown in Figure 4-6 are used at the exit of the
conveyorized degreaser, and are designed to provide additional
time for parts to dry. A drying tunnel is an extension of the
hood, enclosing the exiting conveyor for some distance (i.e. 2
to 10+ feet) from the degreaser. Its length and physical dimen-
sions are dependent on the size of the part to be cleaned, the
type of solvent and the required residence time to fully dry the
individual parts. Even when the unit is controlled and no work
passes through the entry and discharge ports, every square foot
of opening presents a potential for vapor losses. In some in-
stances, additional covers are employed during shut-down hours
to prevent unnecessary emissions.
o Conveyor System - Although the conveyor configuration varies for
each type degreaser included in this group, the design concept
is similar. Conveyors are designed to carry the cold part into
the vapor chamber and out the other end. The product is generally
suspended by hooks or carried in baskets which are attached to
the conveyor. The mechanism for transporting material in the
vibra type conveyor is slightly different; a vibrating tray is
employed to move the material. The rate of movement is critical
for sufficient contact and drying time; however, it also impacts
on the degree of vapor loss to the surrounding area. In addition
to the rate, the quantity of material being processed is another
consideration. Too large a load may cool down and collapse the
4.1-8
-------
TO ADSORPTION DEVICE
OR ATMOSPHERE
SOLVENT
SPRAY PUMP
BOILING SUMP-/
STEAM
SOLVENT SPRAY
RESERVOIR
I
k
DECREASED! \
PART y
CONDENSING
COIL
WATER JACKET
CONDENSATE
TROUGH
Figure 4-6. Typical Emission Points
-------
vapor zone.
The load size is also dependent on the geometry of pieces being
cleaned because greater quantities of crevices and surface areas
will require more time for drying. (Rotating baskets would
normally be used to turn the product around and dislodge some
of the trapped liquid solvent.)
o Condensing Coils - Condensing (cooling) coils are installed on the
inside edges of the conveyorized degreaser. The coils define the
vapor/air interface. They are usually coils consisting of four or
more pipe coils stacked one above the other and located directly
over a condensate trough. The condensing coils include a temper-
ature gauge, a temperature control thermostat, and a high temper-
ature shut-down switch.
o Water Jacket- A water jacket, where applicable, is installed on
the exterior of the degreaser and consists of a box section to
contain cooling water circulating around the degreaser in the
same approximate area as the cooling coils. The water jacket
is also referred to as the freeboard cooler. Its function is to
prevent convection of solvent vapors up hot degreaser walls. In
addition, it reduces "sidewall radiation", which can increase
air turbulence and thus disturb the cold air blanket in the free-
board area. Water jackets and condensing coils should not be
confused with each other or with refrigerated chillers. Chillers
are sometimes used in addition to these units in order to increase
vapor control efficiency.
o Freeboard - Freeboard is that area above the cooling coils extend-
ing to the top of the conveyorized degreaser. The freeboard zone
permits drainage and drying of the work pieces, thereby minimizing
solvent loss and air pollution. The freeboard zone reduces vapor
disturbances caused by air motion in the work area.
o Piping and Sprays - There is a minimum amount of piping included
in the degreaser. Leaks should not be tolerated because they
represent a source of emission and a loss of valuable material.
Drain valves are generally found at the lowest point in the tank.
Piping that is under pressure, such as the spray line, is a
potential source of leaks. Sprays should be operated within
the vapor zone so as to not disturb the air/vapor interface.
Some designs spray the material in a contained chamber within
the degreaser. A spray safety switch is generally provided to
shut off the spray pump when the vapor level drops below the
design level.
o Water Separator - Water enters a degreaser from several sources,
i.e., condensation of atmospheric moisture on condenser coils,
moisture on work pieces being processed, and steam or cooling
water leaks. Water forms a low boiling azeotrope with the sol-
vent and is vaporized. Most degreasers are equipped with a water
separator because uncontrolled water causes corrosion, shortens
solvent life, and increases the vaporization rate of solvent.
The condensed solvent-water mixture drops into the condensate
trough below the condenser coils and flows by gravity to the
separator.
4.1-10
-------
Waste Solvent Disposal - Although there are several methods for
disposing of waste solvent, most current practices of dumping are
unacceptable. The preferred treatment would be the use of recla-
mation services to be accomplished internally or by outside vendors.
Where applicable, direct incineration and chemical landfills are
also viable alternatives. Reclamation using solvent recovery
stills has the greatest appeal for large users because it repre-
sents a savings of valuable material.
4.1-11
-------
4.2 ATMOSPHERIC EMISSIONS
4.2.1 Emission Points
There are several locations in a conveyorized degreaser that may
allow organic liquid or vapor to escape to the atmosphere. These are iden-
tified in Figure 4-6. In general, conveyorized degreasers are hooded and
vented to the outside. Therefore, an emission point is the vent line and
subsequent exhaust. In most instances, a control device such as a carbon
adsorption system is placed in the line to remove organic vapors. Although
constant ventilation of the hood should create a negative pressure and pre-
vent vapors from escaping from the work openings, ventilation rates are kept
2
to a minimum level (< 65 cfm per ft of degreaser opening) to prevent dis-
ruption of the vapor-level boundary and corresponding increased emissions.
However, in minimizing the ventilation rate, the opportunity for vapors to
escape from the work openings increases at the inlet (Location 2) and exit
(Location 3) of the degreaser. In addition, at the exit of the unit the cleaned
material may be carrying out liquid organic material which condensed on its
surface but did not totally dry or drip off while in the degreaser.
As the solvent material is spent and itself becomes contaminated with
impurities, its usefullness decreases. Most conveyorized degreasers are designed
to distill and recycle this material on a continuous basis through the use of
external stills. However, these stills will eventually accumulate wastes and,
depending on the method of disposal, waste solvents may enter the atmosphere
at this point.
Fugitive emissions can occur at any of the piping connections or sump
seals that may have loosened or become worn because of continuous operation.
Where good housekeeping practices are followed, these emission points are elimi-
nated fairly quickly because they are detectable by visual observation, repre-
sent a correctable loss of valuable material, and create a potentially unhealth-
ful work environment.
4.2-1
-------
4.2.2 Parameters Affecting Rate of VOC Emissions
The rate of vapor emissions emanating from the various points pre-
viously discussed is dependent on a variety of operating and design para-
meters. Emissions can be minimized by attempting to achieve certain optimum
conditions; however, it is important to understand the cause and effect
relationship. The following parameters significantly affect VOC emissions
from conveyorized degreasers:
o Drafts .- A fan or other air-moving devices located in the work
area near the degreaser can cause a draft to enter the freeboard
area of the degreaser housing, thereby upsetting the balance of
the air/vapor interface.
o Size of Work Opening - Although conveyorized degreasers are
generally covered, the size of the opening allowing work loads
to enter and exit should be kept to a minimum to reduce the
opportunity for vapors to escape. The term "average silhouette
clearance" is used to define the distance from the edge of the
degreaser opening to the part or the basket or cage conveying
the part. Where hoods are exhausted, the smaller the opening
the greater the capture velocity of the room air traveling
through the area and the greater the control of vapors escaping
at this point.
o Exhaust Rate - The greater the exhaust rate, the greater the
control of vapor escaping from the work openings; however, an
excessive exhaust rate also produces greater emissions because
it disturbs the vapor and air interface within the degreaser,
thereby exhausting high concentrations of organic vapors into
the exhaust gas stream. To achieve both goals the exhaust rate
should not exceed 20 m-Vmin per m^ (65 cfm per ft ) of degreaser
opening.
o Conveyor Speed - As the conveyor speed increases, emissions in-
crease. Increased speeds represent less time for the material
to dry. Therefore, evaporation of the liquid droplets that ori-
ginally condensed on the cold material will take place outside
the hooded portion of the degreaser and will increase emissions.
Too rapid a conveyor speed may also induce drafts that will
create vapor loss at the outlet work opening. Conveyor speeds
must be maintained below 3.3 m/min (11 ft/min) to minimize
losses.
o Type and Magnitude of Load - Atmospheric emissions increase when
the parts being processed in the conveyorized degreaser contain
numerous pockets or liquid traps that allow liquids to be carried
from the degreaser chamber. Liquid trapped in pockets can be re-
moved by placing the working pieces in baskets which are rotated
and tumbled as they move through the degreaser so that they drain
liquid solvent back to the sump. Increases in the magnitude of
the work load will cool the vapor area. A massive load may cause
a collapse of the vapor space and increase emissions. When the
vapor space collapses two situations arise, (1) the vapor/air
4.2-2
-------
layers mix and organic vapors escape and (2) the working pieces
spend less time within the collapsed vapor space and therefore
have less time to evaporate the condensed solvent, resulting
in greater carry out and subsequent emissions.
Solvent Heat Input - Once the solvent's boiling temperature
has been achieved, increasing the heat input to the solvent
will increase the rate of solvent vaporization. If continued,
the cool air blanket generated by the condenser coils may not
be sufficient to retain the increased vapors and breakthrough
could occur, resulting in greater emissions.
Temperature and Flow Rate of the Condensing Coils - The function
of a condensing coil is to limit the upper level of the vapor
zone. A condenser consisting of a coil of pipe through which
cooling water flows, creates a blanket of cool air. The flow
rate and temperature of the water affect the efficiency of a
given set of coils with a given heat input rate. Increasing
flow increases efficiency. Decreasing the temperature of the
water will also increase the efficiency of the coils in support-
ing the vapor layer.
4.2-3
-------
4.3 EMISSION CONTROL METHODS
The EPA Control Technology Guideline (CTG) document for solvent
metal cleaning identifies a number of control strategies for reducing volatile
organic emissions from conveyorized degreasing operation. These form the
basis of defining RACT for the conveyorized degreaser and should therefore
be the focal point of a field inspection. The CTG document suggests two
levels of control. EPA's policy regarding the application of these control
levels is discussed in Chapter 1. Level A represents a relatively low effi-
ciency system, estimated at 25 + 5 percent. Level B, consisting of Level A
plus additional requirements represents a higher efficiency system, estimated
at 60 + 10 percent. The following discussion will address these and other
control measures found in the CTG document. However, the organization is
slightly different. It is divided into three areas: process equipment de-
sign, operating requirements, and control equipment requirements. In addi-
tion, a second series of suggested controls is offered which do not appear in
the CTG document. These controls should be considered by the inspector as
additional means of reducing emissions.
It should be noted that a given control strategy will not provide
equal results for similar degreasers or degreasers used in different appli-
cations. Therefore, each degreaser should be evaluated individually.
4.3.1 RACT Controls
o Process Equipment Design
oo Minimum entrance and exit openings should be pro-
vided by silhouetting the work load. The average
silhouette clearance (distance between the edge
of the openings and the part) should be < 10
percent of the opening width.
oo Safety switches should be included in the design
to prevent emissions during malfunctions and ab-
normal operation.
a. Condenser flow switch and thermostat shut
off sump heat if coolant is either not
circulating or becomes too hot.
b. Spray safety switch shuts off spray pump
or conveyor if vapor level drops excessively.
c. Vapor level control thermostat shuts off sump
heat when vapor level rises too high.
4.3-1
-------
o Operating Requirements
oo Conveyor speed should be < 3.3 m/min (11 ft/min)
to minimize solvent carry-out emissions.
oo Exhaust ventilation should not exceed 20 m^/min
per m (65 cfm per ft ) of degreaser opening
unless necessary to meet Occupational Safety and
Health Administration (OSHA) requirements or the
degreaser is vented to a carbon adsorber.
oo Work place fans should not be used near the
degreaser opening because they will induce
mixing of the air/vapor layer, thereby in-
creasing emissions.
oo Solvent leaks should be repaired immediately,
or the degreaser should be shut down, until
repairs can be made.
oo Water should not be visibly detected in the
solvent exiting the water separator. For
chlorinated solvents, water contributes to
vapor loss because the mixture of water and
solvent has a lower density than that of dry
solvent. In addition, water contributes to
corrosion and creates a low boiling azeotrope
with the solvent in the boiling sump.
oo Down-time covers must be placed over entrances
and exits of conveyorized degreasers immediately
after the conveyor and exhaust are shut down and
removed just before they are started.
oo Disposal or transfer of waste solvents should be
performed in a manner that will not allow greater
than 20 percent of the waste (by weight) to evapor-
ate to the atmosphere. Waste solvents should be
stored in covered containers.
oo Racking parts to allow maximum drainage should
be implemented to minimize carry-out emissions.
o Control Equipment Requirements
oo Rotating baskets, trays, etc., and/or a
drying tunnel should be provided to
prevent solvent drag-out. Such carry-
out is most likely to occur from solvent
hold up in recesses or pockets in the work
being degreased.
oo Covers must be provided for the entrance and
exit in order to close these openings immediately
after shutting down the degreaser. These covers
should close off at least 80 to 90 percent of
the opening to effectively prevent solvent emissions.
4.3-2
-------
oo Refrigerated chillers can be used to control
the upper limit of the vapor zone; or
carbon adsorption systems should be used to
control emissions in the exhaust line of the
degreaser. The ventilation rate (when down-
time covers are open) should be >^ 15 m /min
per m (50 cfm/ft ) of air /vapor area for adsorbers.
oo The exhaust gas from the adsorption system
must contain < 25 ppm solvent by volume
averaged over a complete adsorption cycle.
oo Alternate control systems may be used if they
demonstrate control efficiencies equal to or
greater than the refrigerated chiller or carbon
adsorption units.
4.3.2 Other Controls
Several control techniques are discussed in the literature that
deserve mention although they are not recommended by EPA as RACT requirements.
o The unit is capable of being hooded or covered without
affecting its operation. The enclosure of a degreaser
diminishes solvent losses from the system that result
from the movement of air within the plant.
o Sprays should be designed or adjusted so they do not
cause turbulence at the air/vapor interface; spraying
must be conducted below the vapor line. Spray pressure
should be the minimum necessary for adequate cleansing.
o Overloading work baskets may reduce the vapor temperature
and collapse the vapor zone, thereby increasing the air/
vapor mixing and subsequent emissions. This situation
can be avoided by following equipment specifications for
the allowable work load as determined by a system heat
balance.
o A solvent reclaimer-still to recycle and return a purified
solvent to the solvent sump. This will tend to stabilize
vaporization rates and eliminate emission due to improper
waste disposal methods.
o Where work being degreased contains acidic cutting oils or
other acidic products, acid acceptance and pH determination
should be made to determine the quality of the solvent.
o Absorbent materials such as wood and fabric materials should
not be degreased or used in the basket construction.
o A "good housekeeping" and maintenance program should be in
effect. Clean out doors, line connections, pumps, water
separator, etc., should be checked frequently.
o For large users of solvent, bulk storage may prove more
economical than purchases by individual drums. Where bulk
storage is used, a submerged fill pipe from the top of the
tank should be included in the design of the storage tank.
Alternate controls such as a return vent line to a recovery
still should be investigated.
4.3-3
-------
4.4 INSPECTION PROCEDURES
This section will discuss two types of inspections: (1) field
review and (2) office reviews. Source sampling, still another form of in-
spection, will be discussed in the next chapter.
Field investigations range from brief plant visits to thorough in-
spections that produce a complete data base for enforcement proceedings.
Office reviews rely on the source to furnish information. This approach may
require less time and manpower but the resulting data base is generally less
complete. Office reviews, however, provide a useful screening tool where
the number of potential violators is large.
4.4.1 Field Inspections
After becoming familiar with the plant and its facilities the
inspector should request that the appropriate company official provide in-
formation from company records that will allow the inspector to complete the
worksheets shown in Figure 4-7. The data may also be available from permit
applications. The worksheet divides the required data into two categories:
operating requirements, and control equipment. It also provide^ the RACT
requirements for each category with suggested inspection procedures and
guidelines. With such information, comparisons can be made with past con-
ditions, and with operations at the time of the inspection.
Generally, the inspector would next request the company's assistance
in conducting a full inspection of the facility in order to verify actual
operating conditions. This inspection may take several hours depending on
the number and types of conveyorized degreasers. Figures 4-8 and 4-9 pre-
sent a photo and a schematic of a crossroad degreaser with a rotating basket
which identify general components of a conveyorized degreaser.
All field data, such as temperature of the solvent, conveyor speed,
exhaust flow rate, silhouette clearance, etc., should be seen and verified.
For equipment that is operating, the inspector must be prepared to collect
this data with his own resources. The inspector should concentrate on those
parameters affecting emission rates and control procedures identified earlier
in this chapter.
This information will be compared to the data given by the company
official, and the total data base will be compared to the RACT requirements
for design and operating conditions to determine if a violation exists. At
that time, a reinspection date should be established if it is determined
that the source is not in compliance.
4.4-1
-------
Figure 4-7. Example Worksheet for Field Inspection of
Conveyorized Degreasers
1.
2a.
3.
4.
5.
6.
7.
BUSINESS LICENSE NAME OF CORPORATION, COMPANY, OR INDIVIDUAL OWNER OR GOVERNMENTAL
AGENCY;
MAILING ADDRESS: 2b. PLANT ADDRESS WHERE THIS DEGREASER IS
LOCATED:
SOURCE NO. (PERMIT NUMBER, NEDS ID, ETC.)
NAME AND TITLE OF COMPANY REPRESENTATIVE:
TELEPHONE NO. :
NAME OF OFFICIAL CONDUCTING INSPECTION:
DEGREASER
MANUFACTURER: MODEL NO. SERIAL NO.
INSIDE DIMENSIONS OF TANK (FT.): WIDE X LONG X DEEP
8.
9.
TYPE OF DECREASING:
TYPE OF CONVEYOR
COLD SOLVENT CLEANING t , VAPOR DECREASING i j
TITLE AND CODE NUMBERS OF DRAWINGS, SPECIFICATIONS, STANDARDS, CODES, PROCEDURES AND
DOCUMENTS USED WITH THE INSPECTION
TYPE OF SOLVENT IN USE (SPECIFIC NAME AND MANUFACTURER) :
INSPECTION OBSERVATIONS
RACT REQUIREMENTS
CONTROL EQUIPMENT
1.
Safety Switches
a. Condenser flow
switch & thermo-
stat
SUGGESTED INSPECTION
PROCEDURE
o Confirm that the switch
and thermostat have been
installed.
o If available, check read-
ings of flow and tempera-
ture indicators. For high
boiling solvents, the temp-
erature should be about 8°
to 11°C (15° to 20°F) above
dewpoint of surrounding
atmosphere or 32° to 46°C
(90° to 115°F). For low
boiling solvents (methy-
lene chloride and fluoro-
carbon 113) the exit temp-
erature should be less than
29°C (85°F). Many installa-
tions may not have a temper-
ature indicator at the cool-
ing coil exit. A rough es-
timate of the temperature
may be made if a bleed valve
is available at the exit end
of the coils. Bleed a sample
of coolant into a small vessel
and measure the temperature
with a portable thermometer.
FIELD
OBSERVATIONS
4.4-2
-------
FIGURE 4-7
(Continued)
RACT REQUIREMENTS
SUGGESTED INSPECTION
PROCEDURE
FIELD
OBSERVATIONS
1. (continued)
b. Spray Safety
Switch
c. Vapor level
control thermo-
stats
o If plant is agreeable,
interrupt flow of coolant
and determine if switch is
tripped.
o Confirm that the switch
has been installed.
o Confirm that vapor
level control thermostat
is located just above
cooling coil or jacket.
o Suggested thermostat
settings for four types
of solvents:
-Perchlorethylene
82°C (180°F)
-Trichlorethylene -
68°C (155°F)
-1,1,1-Trichloroethane
60°C (UO°F)
-Methylene Chloride
32°C (90°F) or
about 6°C (10°F) lower
than boiling point of
solvent-water azeotrope
o Read temp, on indicators
2. Minimized openings at
entrance and exit of
conveyor
Determine with a tape
measure that the average
silhouette is less than
10 cm (4 In.) or less than
10 percent of the width
of the opening.
3. Drying tunnel or
rotating baskets
Observe whether the degreaser
is equipped with either of
these devices. Observe
whether parts are wet or
have liquid in crevices
when exiting the degreaser.
4. Refrigerated chiller
Observe indicated coolant
temperature.
oo For subzero chillers
the temperature
should not exceed
-25°C (-1
oo For above freezing
chillers the temperature
should not exceed 5°C
(40°F) .
oo Do not attempt to extract
a sample of coolant from
a refrigerated chiller.
Determine the cooling capacity
from the design specifications,
4.4-3
-------
FIGURE 4-7
(Continued)
RACT REQUIREMENTS
SUGGESTED INSPECTION
PROCEDURE
FIELD
OBSERVATIONS
For subzero
chillers the
minimum cooling
capacity should be
as follows for each
degreaser width:
(The cooling units
are Btu's per hour
per foot of perimeter.)
<3.5 ft - 200
>3.5 ft - 300
>6 ft - 400
>8 ft - 500
>10 ft - 600
For above freezing
chillers the cooling
capacity should be
at least 500 Btu/hr
per foot of perimeter.
5. Carbon adsorption
system with ventilation
>1S m^/min per m
(50 cfm/ft2) of air/
vapor area.
Solvent odors should not be
detectable on the roof down-
wind from the stack.
o Determine the air handling
capacity of the fan,
-or-
If sampling ports are available,
the velocity of the exhaust
gases may be measured with a
swinging vane velocity meter.
Also determine the cross-
sectional area of the duct,
then calculate the cfm.
o After the air volume is
determined from either of the
above methods, obtain the
area of the air/vapor opening
and calculate the cfm per
square foot of opening.
o See the source testing chapter
of this manual.
OPERATING REQUIREMENTS
1. a. Exhaust ventila-
tion should not
exceed 20m /min
per m (65 cfm
per ft2) of de-
greaser open
area unless
necessary to
meet OSHA re-
quirements.
(This ventila-
tion rate is app-
licable if a
carbon adsorber
is not installed.)
b. Work place fans
should not be
used near degreaser
opening.
o Determine the air handling
capacity of the fan,
-or-
If sampling ports are available,
the velocity of the exhaust gases
may be measured with a swinging
vane velocity meter. Also
determine the cross-sectional
area of the duct, then calculate
the cfm.
o After the air volume is
determined from either of
the above methods, obtain
the area of the degreaser
opening and calculate the
cfm per square foot of
degreaser opening.
o Note the location of ventilation
fans near the degreaser.
4.4-4
-------
FIGURE 4-7
(Continued)
RACT REQUIREMENTS SUGGESTED INSPECTION FIELD
PROCEDURE OBSERVATIONS
2. Water should not
be visually detectable
in solvent exiting
the water separator.
3. Conveyor speed should
not exceed 3.3 m/min.
(11 ft/min).
4. Rack parts for best
drainage.
5. Repair solvent leaks
Immediately.
6. Downtime covers
7. a. Do not dispose of
waste solvent or
transfer it to
another party such
that greater than
20 percent of the
waste (by weight)
can evaporate
into atmosphere.
b. Store water sol-
vent only in
covered containers.
o Observe any water present
in the sight glass on the
separator .
o Check conveyor speed
with stop watch.
o Observe whether parts
are racked in a manner
that allows liquid solvent
to collect in pockets and
crevices.
o Inspect for wetted areas
around pump seals, sight
glass, pipes, etc.
o If the unit is not in
operation, observe whether
they are in place.
o Determine if source has
inhouse reclamation
facilities (i.e. still)
or a service contract
with a solvent reclama-
tion firm.
o Confirm that storage is
done with covered con-
tainers by visual inspec-
tion.
o Check for container leakage.
4.4-5
-------
-CONTROL BOX FOR
SAFETY SWITCHES
HOOD
ROTATING BASKET.
WORK OPENING.
Figure 4-8. Cross Rod with Rotating Baskets
4.4-6
-------
LOCATION OF "V-BELT
CONVEYOR DRIVE
REMOVABLE PANEL &
SERVICE DOOR
ROTATING
BASKET RACK
COOLING COILS AROUND
INSIDE OF MACHINE-
EXHAUST & DUCT
WATER
SEPARATOR
STEAM COILS
MOUNTED ON
CLEAN-OUT "
DOORS
THIS
SECTION
TOTALLY
ENCLOSED
LOCKING DEVICE
FOR ROTATING
BASKETS
LOOR LINE
VAPO_R LIQUID SOLVENT LIQUID SOLVENT
GENtRATrNG RINSE SUMP
SU MP
WASH SUMP
Figure 4-9. Cross Rod with Rotating Baskets
(Sketch)
4.4-7
-------
4.4.2 Record Review
Determining compliance of conveyorized degreasers through field
inspections and monitoring is expensive and time consuming. It requires a
great deal of manpower and tends to limit the number of sources that can be
reviewed in a given year. The review of company-furnished records through
questionnaires or letter requests may provide a viable alternative to field
inspections and source monitoring activities for compliance determination.
At minimum, this approach should be considered as a screening tool to identify
candidate sources for comprehensive field inspections, thereby increasing the
effectiveness of the available resources.
This discussion outlines several procedures which may be used when
implementing a record review. Information will be required from the plant
concerning the design, operation and maintenance of the equipment.
4.4.2.1 Review of Design, Operation, and Maintenance Data
The first requirement of this procedure is the development of
standard questionnaires that can be sent out as part of a Section 114 request
to the applicable sources. The type of information required is similar to
what is identified on the inspection forms illustrated in Figure 4-7. It
is important that the source understand what is being requested and that
the request be realistic because the entire process of making compliance
judgments using this procedure is highly dependent on the reliability of the
information furnished.
An example questionnaire is provided as Figure 4-10 and should be
used as a guide only. It is suggested that the agency develop its own form
which would be specific to the program. For example, a screening program
may only require key data, while a more extensive request is necessary if
compliance determinations are to be attempted. Three types of data are
suggested for review: design information, operational information, and main-
tenance records. The design data should be readily available, while opera-
tional and maintenance may require the source to create a special logging
system in order to comply with the agency's request.
4.4-8
-------
Figure 4-10. Questionnaire for Conveyorized Degreasers
1. BUSINESS LICENSE NAME OF CORPORATION, COMPANY, OR INDIVIDUAL OWNER OR GOVERNMENTAL
AGENCY:
2. a. MAILING ADDRESS:
2. b. PLANT ADDRESS WHERE THIS DEGREASER
IS LOCATED:
3. SOURCE NO. (PERMIT NUMBER, NEDS ID, ETC.)
4. NAME AND TITLE OF AUTHORIZED COMPANY REPRESENTATIVE FURNISHING DATA:
SIGNATURE:
5. TELEPHONE NO.:
6. DEGREASER
MANUFACTURER:
MODEL NO.
INSIDE DIMENSIONS OF TANK (FT.):
WIDE X
SERIAL N0._
LONG X DEEP
CONVEYORIZED: YES i 1 NO i 1 IF YES, GIVE TYPE
TYPE OF DECREASING: COLD SOLVENT CLEANING i \ VAPOR DECREASING
WORK LOAD DESIGN SPECS
7. CONTROL EQUIPMENT: NAME
CFM
_TYPE
EFF.
MODEL NO.
8. DRYING TUNNEL: YES nzZ! NO \ 1
TUMBLING OR ROTATING BASKETS: YES
TANK COVERED WHEN NOT IS USE: YES
NO
NO
9. SAFETY SWITCHES:
[-—] CONDENSER FLOW SWITCH AND THERMOSTAT
r—I SPRAY SAFETY SWITCH
VAPOR LEVEL SAFETY SWITCH
10. REFRIGERATED CHILLERS
DESIGN TEMPERATURE FOR REFRIGERANT
°C or
11. DISPOSITION OF
SPENT SOLVENT FROM DEGREASER_
SLUDGE FROM STILL
SOLVENT FROM ADSORBER
12. OPERATING PARAMETERS
ACTUAL CONVEYOR SPEED
FLOW RATE OF EXHAUST GAS
TEMPERATURE OF SOLVENT BATH_
CHEMICAL NAME OF SOLVENT
JT/MEN
_CFM
°C
or
4.4-9
-------
Criteria for review of the data should be established prior to fi-
nalizing the questionnaire. Obviously the criteria will address the overall
objectives of the review program (e.g., screening program or compliance
determination). In general, however, the design data should be compared to
the original construction permit and the design specifications and be at
least as stringent as RACT. This review would include such items as exhaust
ventilation rates, types of safety switches, design conveyor speed, and the
availability of control equipment. Operational information should be com-
pared to operating permits and operational specifications defined as RACT.
These parameters would include the silhouette distance, the use of down-time
covers, the quantity and type of parts being cleaned, the method of waste
solvent disposal, and actual ventilation rates. Maintenance records should
include repair or replacement records and some statement as to the general
condition of the equipment.
4.A.2.2 Review Waste Solvent Disposal Procedures
A description of waste solvent disposal methods used by the source
must be requested in the questionnaire initiated by the agency (example shown
in Figure 4-10). A comparison should be made with the RACT operating require-
ments ("not greater than 20 percent can evaporate into the atmosphere"), and
data on other acceptable practices which are readily available.
On conveyorized vapor degreasers where large quantities of
solvent are used, it becomes economical to install a solvent distillation
still for solvent reclamation. On installations of this type, both the
sludge and solvent are pumped to the solvent still where the solvent is
reclaimed. The liquid is heated to its vaporization temperature and the
resulting vapors flow into a chilled condensing chamber where the vapors
condense back to liquid. The liquid is then circulated back to the con-
veyorized vapor degreaser for further use. In this type of operation, only
make-up liquid solvent is added, as needed. There are alternate approaches
to an inhouse still, such as service contracts with outside agents which
may be more attractive to the source and will also meet the RACT require-
ments.
The sludge remaining in the still along with water and spent un-
reclaimable solvent should be disposed of in accordance with the Resource
Conservation and Recovery Act. Pursuant to this legislation EPA has pro-
posed regulations for the disposal of hazardous wastes at 43FR58946 (December
18, 1975).
4.4-10
-------
CHAPTER 5
EMISSION TESTING OF CARBON ADSORPTION SYSTEMS
5.1 INTRODUCTION
The compliance status of a carbon adsorption system cannot always be
determined by a routine source inspection or by an engineering evaluation
conducted in the office. For those cases where the compliance status is
uncertain or where violations are anticipated, measurement of the solvent
concentration in the effluent gases will be necessary to establish the com-
pliance status. It would be ideal if there were an accurate, quick, easy,
inexpensive compliance test method available for inspectors. Unfortunately,
the present methods that are sufficiently accurate (+ 10% or better) for
compliance concentration measurements of halogenated organics are not parti-
cularly quick, easy, and inexpensive; and the methods that meet these latter
requirements are not sufficiently accurate for exact compliance determinations•
Because no single method currently exists that satisfies all the requirements
of an ideal compliance test method, two methods have been selected. The first
method is a screening method that is quick, easy, and relatively inexpensive.
The second method is designed to provide the accuracy necessary for full fledg-
ed enforcement compliance actions. The screening method and the recommended
reference method are presented in Section 5.2 and Section 5.3, respectively.
In addition, a method is described in Section 5.4 for conducting a material
balance so that emissions can be determined on a pounds per hour or pounds
per day basis.
The screening procedure is designed to be quick, easy, and inexpensive.
The primary objective is to provide an inspector with a method that can iden-
tify those sources that are well below the emission concentration limitation
as well as those sources that are well above the limitation, while not adding
significantly to the inspectors work load nor requiring a substantial invest-
ment in either personnel training or equipment. The screening method can be
5.1-1
-------
used by an inspector during a routine source inspection, and will add only
15 to 30 minutes to the field inspection time. Personnel can be trained to
use the method in 1 to 2 hours. Equipment for the screening method will
cost from $2,000 to $4,000.
The screening method provides an instantaneous reading of apparent sol-
vent concentration in the gases emitted from solvent adsorption systems.
The instruments used cannot identify specific compounds, nor can they select-
ively measure individual compounds in a mixture of solvent vapors. They
respond to practically all volatile organic compounds, although the magnitude
of the response varies from compound to compound. For these reasons, the
screening method cannot provide the quality of data necessary for an enforce-
ment action. What the screening method can do, however, is indicate the
apparent compliance status of sources, thereby significantly limiting the
number of full compliance tests that must be conducted.
The EPA guideline document for solvent metal cleaning does not specify a
test method for measurement of solvent emission concentrations. However,
EPA has prepared a draft test procedure specifically designed to provide
accurate concentration measurements of halogenated solvent vapors emitted
from sources such as the subject degreaser carbon adsorption systems. The
draft procedure is entitled, "Determination of Halogenated Organics from
Stationary Sources"!. The method provides accurate concentration measurements
of individual solvent compounds even if a mixture of solvents is present. It
is recommended that this procedure be adopted as the compliance verification
method for determination of VOC emission concentrations from degreaser carbon
adsorption systems that are subject to regulations which incorporate the
EPA guideline document. The CTG recommends limiting the solvent content in
the exhaust gases to 25 parts per million (ppm) by volume of solvent.
As with most source testing procedures, the recommended compliance
verification method requires special equipment and trained personnel. The
method requires integrated bag sampling equipment for sample collection and
a gas chromatograph (GC) with a flame ionization detector (FID) for sample
"Determination of Halogenated Organics from Stationary Sources", Emission
Measurements Branch, ESED, EPA, Research Triangle Park, North Carolina,
January 1979.
5.1-2
-------
analysis. A single source test, using the recommended reference method,
will require approximately 30 to 40 labor hours, assuming the personnel are
previously trained and the equipment is already set up for this purpose.
The total cost of the necessary equipment will range from $8,000 to $15,000.
It is apparent that conducting source tests is expensive in both labor and
equipment requirements. Furthermore, source testing should not be attempted
by persons unfamiliar with source sampling, nor by those who are unfamiliar
with the analyzers. In light of these facts, the importance of screening
tests is quite obvious. Reference method compliance testing should be reser-
ved for those cases where screening tests have indicated potential violations
and further proof is needed.
The purpose of testing is to determine if the emission standards will be
met when degreasers are operated under conditions that create the maximum
solvent vapor emissions. Therefore, the plant operating conditions during
a test should be as follows:
o The production rate should be the maximum rate for satisfactory
operation of the work material being processed and for the type of
vapor degreaser being used.
o The testing should be conducted during operating cycles which pro-
duce the maximum emissions.
o Work parts which produce maximum emissions (i.e., parts with porous
surfaces, crevices, large mass, etc.) should be processed during
testing. The conveyor speed (mpm) should be the maximum allowable.
The solvent boiling rate and the vapor space barrier chilling coil
temperature should be at normal operating conditions. No special
work material or conditions should be used that would cause opera-
tions to be other than normal for that particular conveyorized de-
greaser application, except as specifically mentioned above.
When conducting a screening test the inspector should first determine
if the process is operating normally. Although it is desirable to perform
the screening test under conditions of maximum emissions, it is not mandatory
as it would be for reference method compliance testing.
5.1-3
-------
5.2 SOURCE TESTING SCREENING METHOD
This procedure contains seven major sections. The title of each major
section and the page number where each is found is as follows:
5.2.1 Applicability 5.2-1
5.2.2 Principle 5.2-1
5.2.3 Range and Sensitivity 5.2-2
5.2.4 Calibration Apparatus 5.2-2
5.2.5 Sampling and Analysis Apparatus 5.2-4
5.2.6 Calibration Procedures 5.2-12
5.2.7 Sampling Procedures 5.2-14
5.2.1 Applicability
This suggested procedure is applicable to the measurement of single-
component solvent concentrations in the effluent gases from carbon adsorption
systems installed on degreasers using organic solvents. It assumes that quan-
tities of other organic compounds which are present as oils or stabilizers
are insignificant in comparison to the solvent emissions. The procedure is
intended to provide a quick and relatively inexpensive approach that can be
used by field inspectors to estimate solvent concentrations. It is not
intended to be a compliance testing method.
5.2.2 Principle
Commercially available portable organic vapor analyzers are used to
measure solvent concentration directly in the stack gases from carbon adsorp-
tion systems. The units are battery powered and are safe for use in explo-
sion hazard areas, provided they are certified intrinsically safe by the
Factory Mutual Laboratories or are designed for use in Class I, Division 1
or 2 hazardous areas as designated by the National Electrical Code.l Detec-
tion principles available include flame ionization, catalytic oxidation/
thermal conductivity, and photoionization. The photoionization unit is an
in-situ analyzer, while the flame ionization and catalytic oxidant/thermal
conductivity units are extractive analyzers. The units are completely self
contained requiring no ancillary sample handling equipment.
1 "National Electric Code 1968", National Fire Protection Association,
Publication NFPA No. 70-1968, Boston, 1968
5.2-1
-------
5.2.3 Range and Sensitivity
The range and sensitivity varies among the different types of instru-
ments that are available.
5.2.4 Calibration Apparatus
Calibration is most easily accomplished by obtaining commercially
prepared and certified calibration gas mixtures. If this is done, then
only a minimum of equipment is required. The calibration gas mixtures must
contain the same solvent that is used in the degreaser to be tested. Inclu-
sion of any other organic materials must be limited to less than 0.1 ppm as
methane. The diluent gas should be pure air containing less than 0.1 ppm
organics (as methane). The gas manufacturer should recommend a maximum
shelf life for each cylinder, based on a maximum concentration change of + 5
percent from the certified value. The date of gas cylinder preparation,
certified concentration, and recommended shelf life should be provided by
the gas manufacturer.
If commercially prepared calibration gas mixtures are not available,
or if the decision is made to prepare the mixtures in-house, then more equip-
ment is required. Suitable calibration gas mixtures can be prepared from
pure solvent liquid and zero air. Such mixtures, however, should be prepared
fresh each day, unless their stability for a longer period has been demon-
strated.
The two following sections list the appraratus required for calibra-
tion using either commercially prepared or in-house prepared calibration gas
mixtures.
5.2.4.1 Calibration Apparatus for Use With Commercially Prepared Calibration
Gas Mixtures
o Air—zero grade, certified by the manufacturer to contain less
than 0.1 ppm organics (as methane).
o Calibration Gas Mixtures—approximately 5, 25, and 50 ppm of the
specific solvent in zero air, with less than 0.1 ppm of other
organic material (as methane). Concentration of solvent and or-
ganic impurities to be certified by the manufacturer.
o Gas pressure regulators—for zero air and solvent gas cylinders.
5.2-2
-------
o Tedlar bags—30 liter capacity with an integral stainless steel
valve. A separate bag is reserved for each calibration gas con-
centration. Other bag materials may be used if it is proven that
they do not affect the sample integrity.
5.2.4.2 Calibration Apparatus for Use With Standard Gas Mixtures Prepared from
Pure Solvent Liquid
o Air—zero grade, certified by the manufacturer to contain less
than 0.1 ppm organics (as methane), for zero gas and dilution of
solvent calibration gases.
o Solvent—99.9+ percent pure, must be the same as the solvent used
in the degreaser being tested.
o Gas pressure regulator—for cylinder of zero air.
o Tedlar bags—50 liter capacity with integral stainless steel valve.
Other bag materials may be used if it is proven that they do not
affect the sample integrity.
o Midget impinger—30 ml capacity, with septum.
o Hot plate—small laboratory size.
o Beaker—500 to 1,000 ml size.
o Syringe—1.0 microliter (yl) capacity.
o Syringe—5.0 microliter (yl) capacity.
o Syringe--25.0 microliter (ul) capacity.
o Dry gas meter—1 liter per revolution, smallest scale divisions no
greater than 0.01 liters, +_ 1% accuracy. Meter must be calibrated
with a wet test meter or a spirometer at least every 12 months.
Alternatively a calilbrated flowmeter may be used instead of a dry
gas meter, provided it is accurate to + 1.0 percent.
o Vacuum pump—-to evacuate the bags.
o Connecting tubing and fittings—Teflon tubing, 6.4 mm outside
diameter. Stainless steel or Teflon fittings as required.
5.2-3
-------
5.2.5 Sampling and Analysis Apparatus
The following instruments are listed as examples of the types of
portable analyzers applicable to this procedure. Other units may also be
available which will perform satisfactorily.
o FID - OVA Model 108 or 128, Century Systems Corporation
o Catalytic Oxidation/Thermal Conductivity - TLV Sniffer, Bacharach
Instruments Company
Accessory hand-held probes which are available for all of the above
instruments should be used.
5.2.6 Laboratory Calibration Procedures
These procedures are designed to determine if an analyzer is respon-
ding properly and to determine the analyzer response curve for each different
solvent. Analyzer response will normally be linear over the narrow range of
concentrations (zero to 50 pppm) used for calibration. The slope of the
response curve will be different for each solvent, however. The calibration
curves allow the operator to convert analyzer response (instrument reading)
to actual concentration.
5.2.6.1 Preparation of Standard Gas Mixtures
The gases used for calibration can come from several sources. If
they are available, commercially certified span gas mixtures are preferable
for analyzer calibration. The span gas mixtures should contain zero air as
the diluent. The solvent vapor in the span gas mixture must be the same as
the solvent used in the subject degreaser. At lease three different span
gas concentrations should be used in order to cover the range of concentra-
tions expected in the field. For most carbon adsorption systems, span gas
concentrations of 5, 25, and 50 ppm of solvent should be adequate. In addi-
tion to the span gases, a zero gas (certified by the manufacturer to contain
less than 0.1 ppm organics, as methane) is required.
If certified solvent span gas mixtures can be obtained, they are
used directly to calibrate the analyzer. If such mixtures are not commer-
cially available, then suitable calibration gas mixtures can be prepared by
diluting pure solvent liquid. Prior to use, each bag must be numbered and
must be leak checked using one of the following procedures.
5.2-4
-------
o Pressurize the bag to 5 to 10 cm H20 (2 to 4 in. 1^0) using a water
manometer to measure the bag pressure. Allow to stand for 10
minutes. Any displacement of the water manometer indicates a
leak.
o Pressurize the bag to 5 to 10 cm 1^0 (2 to 4 in. H20) and allow
to stand overnight. A deflated bag indicates a leak.
Note: Bag pressurization can easily be accomplished by placing
a book or other suitable weight on a partially inflated bag.
If commercially prepared calilbration gas mixtures are used, transfer
20 to 25 liters from each cylinder into individual Tedlar bags. Before each
use the bags must be numbered, leak tested as discussed above, and evacuated.
Connect each bag to the appropriate gas cylinder regulator with a short piece
of Teflon tubing. Flush the tubing with the calibration gas just prior to
connecting the bag. Slowly fill each bag with calibration gas. Fill a bag
with zero air in the same manner. Record the appropriate data on the Cali-
bration Curve Data Sheet (Figure 5-1). (Caution: To eliminate contamination
if bags are reused, a bag should only be refilled with the solvent it origin-
ally contained. Furthermore, the new gas mixture standard should never be
a lower concentration than the previous gas mixture standard.)
If the calibration gas mixtures are to be prepared from solvent
liquid, assemble the apparatus as shown in Figure 5-2. Slip a short piece
of 4.8 mm inside diameter rubber tubing over the Teflon tubing that attaches
to the bag valve. Tighten a pinch clamp on the rubber tubing to seal the
tubing. Back off the pressure control knob on the zero air cylinder regula-
tor so that no gas will flow when the cylinder is opened. Close the outlet
valve on the zero air cylinder regulator and open the zero air cylinder value.
The outlet pressure gauge on the regulator should indicate zero pressure.
Open the regulator outlet valve slightly. Slowly turn the regulator pressure
control knob (normally in a clockwise direction) until gas just begins to
flow through the regulator. Allow the pressure in the system to reach 5 to
10 cm H20 (2 to 4 in. H20) and close the regulator outlet valve. Observe
the manometer water level for a 1 minute period. Any change in the manometer
water level indicates there is a leak in the system that must be corrected
before proceeding. After a successful leak check is obtained, remove the
5.2-5
-------
Figure 5-1. Example Calibration Curve Data Sheet
Calibration Run Number
Date
Location
Analyst
Resultant Calibration Curve Number
Analyzer Type
Analyzer I.D. Number
Solvent Gas (name)
Zero Mixture Mixture Mixture
Air 1 2 3
Bag I.D. Number
Bag Size (liters)
Source of Calibration Gas
Calibration Gas Cylinder Number
Calibration Gas Bag Number
Calibration Gas Concentration (opm)
Analyzer Range Setting
Analyzer Span Potentiometer Setting
Analyzer Zero Check Response
Analyzer Internal Span Check Response
Analyzer Response to Zero Air
Response to Gas Mixture
5.2-6
-------
TEFLON
TUBING
WATER
MANOMETER
ro
I
•-j
MIDGET /"
IMPINGER
THERMOMETER
SYRINGE
J
SEPTUM
BOILING WATER
BATH
INTEGRAL
VALVE
HOT PLATE
-TEDLAR BAG
CAPACITY 50 LITERS
ZERO AIR
CYLINDER
Figure 5-2. Apparatus for the Preparation of Calibration Gas Mixtures from Liquid Solvent
-------
rubber tubing and pinch clamp from the Teflon tubing. Using the regulator
outlet valve and the pressure control knob, obtain a flow through the system
of approximately 3 liters/minute. Flush the system for 5 minutes, then
close the regulator outlet valve. Turn on the hot plate and allow the water
bath to reach boiling. Evacuate a 50 liter Tedlar bag that has passed a
leak test , and connect it to the impinger outlet tubing with the bag valve
closed. Record the initial meter readings (M^) on an appropriate data sheet,
such as the one shown in Figure 5-3. Open the bag valve and the zero air
cylinder valve. Adjust the filling rate to approximately 3 liters/minute.
Record the meter pressure (Pm), the meter temperature (Tm), and the baromet-
ric pressure (P^). Determine the proper amount of solvent from Table 5-1.
Select the smallest syringe that will accommodate the solvent volume, and
fill the syringe with the desired amount of pure liquid solvent (Vg). Push
the syringe needle through the impinger septum and inject the solvent into
the impinger. Use a needle of sufficient length to permit injection of the
liquid below the air inlet branch of the tee. Remove the syringe.
Complete filling of the bag, recording the meter temperature and
pressure at 5 minute intervals. When the desired amount of air (preferably
40 liters) has been metered into the bag close the zero air cylinder and the
bag valve. Record the final meter reading (Mf). Disconnect the bag from
the impinger outlet. Transfer the bag to a protected area out of direct
sunlight and allow it to equilibrate for approximately 1 hour. Gentle mani-
pulation of the bag will speed the equilibration process.
Calculate the average meter meter temperature (T^) and pressure
(pma) from the readings taken while filling the bag. Calculate the actual
resultant concentration using the following equation:
(Vs)(Qs)(103)(24.04)(760)(Tma + 273)(106ppm) Equation 5-1
Cppm = — — — - — • — - — — • • ' • -- — — — • — - • — ~ -
(MWg)(Vn)(106) (Pb + P^ ) (293)
13.6
where:
= solvent concentration, ppm by volume
V = volume of liquid solvent, /u,l (1 microliter = 10~ liter)
Qs = density of liquid solvent at temperature used, g/ml = mg//iAl
5.2-8
-------
Figure 5-3 . Example Span Gas Preparation Data Sheet
Run Number
Analyst
Dry Gas Meter Number
Dilution Gas (name)
Dilution Gas Cyl. Number
Bag Material
Bag Capacity
Nominal Dilution Gas Flow Rate
Barometric Pres., P., (mm Hg)
Bag I.D. Number
Date
Solvent (name)
Solvent Liquid Lot Number
Solvent Density, Q , g/ml
Volume of Solvent Used, V , (yl)
Ambient Temperature
Data for Calib. Curve Number
Time
(24-Hour Clock)
Gas Meter
Reading
(liters)
NET, Vn -
Gas Meter
Temperature,
V <°c>
AVS- Tma '
Gas Meter
Pressure,
Pm' (mm H20)
AVG, P =
ma
For Liquid Solvent: C
ppm
_ (VsHQs)(103)(24.04)(760)(Tma + 273)
ppm
ppm
^V (Pb +T
( )( )(24,040)(760)( + 273)
ppm
5.2-9
-------
TABLE 5-1
ro
INJECTION VALUES FOR PREPARATION OF STANDARDS
Perchloroethylene C2C14
Trichloroethylene C2HC13
1,1, 1-Tr ichloroethane C2H3Cl3
Methylene Chloride CH2Cl2
Trichlorotrifluoroethane C2C13F3
Carbon Tetrachloride CC14
Ethylene Dichloride C?HAC1
MOLECULAR WT
(MWS)
165.85
131.40
133.42
84.94
187.38
153.84
98.96
DENSITY AT 293° K
(Qs>
1.6230
1.4649
1.4384
1.3255
1.5790
1.5940
1.2569
Vs, pi LIQUID REQUIRED IN 40 1 AIR
FOR APPROXIMATE CONCENTRATION OF:
5 PPM 25 PPM 50 PPM
0.85
0.75
0.77
0.53
0.99
0.80
0.66
4.25
3.73
3.86
2.67
4.94
4.01
3.28
8.5
7.5
7.7
5.3
9.9
8.0
6.6
-------
= conversion factor: mg to fig
24.04 • volume occupied by one /u,g-mole of pure solvent at 20°C
(293°K) and 760 mm Hg,
Pb - barometric pressure, mm Hg
pma * average meter pressure (gauge), mm H20
293 - standard temperature (20 + 273), °K
13.6 = conversion factor, mm l^O/mm Hg
MWS = molecular weight of solvent, /ig//Ag-mole = g/g-mole
Vn - net metered volume, liters. Vn = final meter reading (Mf)
minus initial meter reading
» conversion factor: liters to /u.1
760 = standard pressure, mm Hg
Tma = average meter temperature, °C
273 - constant added to °C to obtain °K
10^ ppm - conversion factor: volume fraction to ppm
If the laboratory conditions are close to standard conditions the
above equation can be simplified by eliminating the temperature and pressure
correction terms. As long as the meter temperature is within the range of
6° to 34°C (43° to 93°F), eliminating the temperature correction will intro-
duce a maximum error of 5% in the calculated concentration. Similarly, if
the meter pressure is within the range of 722 to 792 mm Hg (28.43 to 31.42
in. Hg), eliminating the pressure correction will introduce a maximum error
of 5% in the calculated concentration. Therefore, if both temperature and
pressure corrections are eliminated, the maximum error that could result
would be 10%, and for most laboratory conditions the error would be much
less. Removing the temperature and pressure corrections and combining con-
stants yields the following simplified equation:
(VS)(QX)(24,040) Equation 5-2
(MWs)(Vn)
5.2-11
-------
5.2.6.2 Determination of Analyzer Calibration Curve
Assemble the sampling probe to the analyzer and leak check the sys-
tem in accordance with the manufacturer's instructions. Set the range switch
to the lowest range that will allow analysis of the 50 ppm solvent gas mixture
without an off-scale response. This setting will vary, depending on the type
of analyzer used and the analyzer gain setting. In some cases it may be
necessary to adjust the analyzer gain to obtain the desired response. Always
refer to the manufacturer's instructions before performing any adjustments
inside the instrument case. Adjust the analyzer zero and span following the
manufacturer's instructions. (Use the internal electronic span check or manu-
facturer's span gas as appropriate for the specific analyzer being used.) Re-
cord the final analyzer settings and the other required data on the Calibra-
tion Curve Data Sheet (Figure 5-1).
Assemble bags of calibration gases prepared as discussed in Section
5.2.6.1. Tedlar bag gas mixture standards of methylene chloride, ethylene
dichloride, and trichlorotrifluoroethane should be prepared fresh each day.
Trichloroethylene and 1,1,1-trichloroethane can be kept for 2 days, while
perchloroethylene and carbon tetrachloride can be kept for 10 days from the
date of preparation. Connect the analyzer probe to the bag containing zero
air. Allow the analyzer to stabilize and record the analyzer response on the
Calibration Curve Data Sheet. Similarly determine the analyzer response for
each of the gas mixture bags, starting with the most dilute concentration and
proceeding to the next higher concentration. After completing the gas mix-
tures, recheck the analyzer response to the zero air. If the zero air re-
sponse has drifted more than 5 percent the run should be repeated.
Plot the analyzer response for each of the calibration gases (in-
cluding the zero air) versus the actual concentration of each gas. Figure
5-4 is a typical calibration curve developed in this manner. The points
should fall along a straight line. If any of the plotted points fall farther
than 10% from the average line, those points should be checked to determine
if an error has been made. The resulting curve is then used to convert
source measured analyzer response to solvent ppm concentrations.
5.2-12
-------
Calibration Curve Number — r/?V-
Analyzer O iss -/2& -syV / S.
Range
O TV;
Internal Calibration Point
Date
50
40
Q.
CL
Q_
00
30
20
10
CALIBRATION GAS
INSTRUMENT INTERNAL ELECTRONIC
CALIBRATION OR MANUFACTURER'S
SPAN GAS
10
20
30
40
CALIBRATION GAS CONCENTRATION
(ppm 1,1,1-trichloroethylene)
Figure 5-4. Example Calibration Curve
50
5.2-13
-------
Once a calibration curve is developed for each solvent encountered
in the field, analyzer calibrations utilizing the instrument internal elec-
tronic span check or manufacturer's span gas are sufficient for routine
operation. Analyzers should initially be recalibrated as outlined in this
section every 3 to 6 months to verify the accuracy of the internal electronic
span check or manufacturer's span gas. If the periodic recalibrations repeat-
edly show a zero or span drift of more than 10 percent, more frequent recali-
brations, as outlined in this section, should be performed. If the periodic
recalibrations show that the instrument and the electronic span check or
manufacturer's span gas are stable, a longer interval between recalibration
can be instituted.
5.2.7 Sampling Procedures
Prepare the analyzer for field use in accordance with the manufactur-
er's instructions. Connect the sampling probe (where applicable) to the ana-
lyzer and leak check the system in accordance with the manufacturer's instruc-
tions. Make sure the batteries are fully charged and the instrument is
operating properly before leaving the office.
When ready to perform the sampling again leak check the system.
Zero the analyzer as directed by the manufacturer and check the span calibra-
tion using the internal electronic calibration check. Adjust the analyzer
gain as necessary so that the analyzer response is equal to the value used
during the last laboratory calibration. For those instruments that do not
have an internal electronic calibration check, use calibration gas available
from the manufacturer and adjust the analyzer gain so that the analyzer
response is equal to the value obtained with the same concentration span gas
during the last laboratory calibration. With the analyzer operating, place
the end of the probe at the centroid of the stack. Seal off the sampling
port so that no dilution air enters the stack around the probe. Allow suffi-
cient time for the analyzer response to stabililze (normally from 5 to 90
seconds is sufficient) and record the instrument reading on an appropriate
field data sheet, such as shown in Figure 5-5. Be sure to fill in all the
blanks on the data sheet.
Avoid sampling during the first five minutes after an adsorption
bed is placed on-line as the solvent concentration will tend to be high for
5.2-14
-------
Figure 5-5. Solvent Vapor Field Data Sheet for
Screening of Carbon Adsorption Systems on
Vapor Degreasers
Plant Name
Address
Sketch of
Sampling Location
Analyzer Operator
Date
Run Number
Unit Sampled
Sampling Location
Adsorber Bed I.D. Number
Adsorber Bed On-Line At
Length of Normal On-Line Cycle
Analyzer Type
Analyzer I.D Number
Analyzer Calibration Curve Number
Leak Check Results; Beginning
Analyzer Sampling Rate
End
Analyzer Zero Response; Beginning
Analyzer Span Response; Beginning
Span Source
_, End
, End
Top View
Side View
Time
(24-Hr. Clock)
Analyzer
Range
Setting
Analyzer
Span
Setting
Average
Analyzer
Response
( )
Actual
Concentration
(ppm )
5.2-15
-------
a short time after a bed is switched. If possible try to obtain measurements
during the last portion of a bed cycle to determine if breakthrough is occur-
ring. If low concentrations (<25 ppm) are found at the end of a cycle it is
a strong indication that the system is operating in compliance. If break-
through is found and the measured concentrations exceed the 25 ppm limitation,
then multiple samples should be taken at regular intervals throughout an
entire cycle. This will allow the calculation of the average emission con-
centration during the cycle.
At the completion of the sampling run, perform a final leak check
and check the analyzer zero and span response. If the system has developed
a leak or if the analyzer has drifted more than 5% for either zero or span,
the run should be repeated.
Using the calibration curve prepared according to Section 5.2.6.2,
determine the actual solvent concentration that corresponds to the observed
analyzer response. Record these corresponding solvent concentrations on the
field data sheet. If multiple samples have been obtained, calculate the
average solvent concentration and enter it on the field data sheet.
5.2-16
-------
5.3 DRAFT SOURCE TESTING COMPLIANCE VERIFICATION METHOD
The methodology required for compliance testing requires the use of
accurate instruments, operated by experienced personnel, in a careful and
thorough manner. The following testing procedure is designed to accurately
determine the average solvent concentration in the exhaust gases of a carbon
adsorption system during a complete adsorption cycle, regardless of whether
the solvent is a single compound or a mixture of compounds. The procedure
utilizes a gas chromatograph with a flame ionization detector that can be
used to separate a mixture of solvent vapors and determine the concentration
of each component.
Samples are collected by the integrated bag technique. A bag is
filled continuously over an entire cycle, yeilding a single sample that repre-
sents an average of the emissions during that cycle. Three such cycles
should be sampled and the results of the three runs should be averaged to
determine the average emission concentration for the source. The samples
need not be analyzed in the field, provided the bag samples are properly
protected as outlined in the method.
The method has not been promulgated as an EPA Reference Method, so
no method number has been assigned at this time. The method was written in
anticipation that either an NSPS or NESHAP regulation would be promulgated
for drycleaning and degreasing, so it is quite appropriate for testing de-
greaser carbon adsorption systems. The draft method is reprinted in its
entirety in the sections below.
INTRODUCTION
Performance of this method should not be attempted by persons un-
familiar with the operation of a gas chromatograph, nor by those
who are unfamiliar with source sampling, as there are many details
that are beyond the scope of this presentation. Care must be
exercised to prevent exposure of sampling personnel to hazardous
emissions.
5.3-1
-------
5.3.1 Principle and Applicability
5.3.1.1 Principle
An integrated bag sample of stack gas containing one or more halo-
genated organics is subjected to gas chromatographic (GC) analysis, using a
flame ionization detector (FID).
5.3.1.2 Applicability
The method is applicable to the measurement of halogenated organics
such as carbon tetrachloride, ethylene dichloride, perchloroethylene, tri-
chloroethylene, methylene chloride, 1-1-1 trichloroethane, and trichlorotri-
fluoroethane in stack gases only from specified processes. It is not appli-
cable where the gases are contained in particulate matter.
5.3.2 Range and Sensitivity
The procedure described herein is applicable to the measurement of
halogenated organics in the 0.1 to 200 ppm range. The upper limit may be
extended by further calibration or by dilution of the sample.
5.3.3 Interferences
The chromatograph column with the corresponding operating parameters
herein described has been represented as being useful for producing adequate
resolution of halogenated organics. However, resolution interferences may be
encountered on some sources. Also, the chromatograph operator may know of a
column that will produce a superior resolution of the particular compound of
interest without reducing the response to that compound, as specified in Sec-
tion 5.3.4.3.1.
In any event, the chromatograph operator shall select a column which
is best suited to his particular analysis problem, subject to the approval of
the Administrator. Such approval shall be considered automatic provided that
confirming data produced through a demonstrably adequate supplemental analytical
technique, such as analysis with a different column or GC/mass spectoscopy, is
available for review by the Administrator.
5.3.4 Apparatus
5.3.4.1 Sampling
See Figure 5-6.
5.3-2
-------
Ul
•
OJ
(-0
FILTER
(GLASS WOOL)
STACK WALL
M
PROBE
TEFLON
SAMPLE LINE
QUICK
CONNECTS
MALE
QUICK
CONNECTS
FEMALE
FLOW METER
TEDLAR BAG
1X1
CHARCOAL TUBE
RIGID LEAK-PROOF
CONTAINER
PUMP
Figure 5-6. Integrated Bag Sampling Apparatus Assembly
-------
5.3.4.1.1 Probe
Stainless steel, Pyrex glass, or Teflon tubing according to stack
temperature, each equipped with a glass wool plug to remove particulate
matter if particulate matter is present.
5.3.4.1.2 Sample Line
Teflon, 6.4 mm outside diameter, of sufficient length to connect
probe to bag. A new unused piece is employed for each series of bag samples
that constitutes an emission test.
5.3.4.1.3 Connections
Male (2) and female (2) stainless steel quick connects, with ball
checks (one pair without) located as shown in Figure 5-6.
5.3.4.1.4 Sample Bags
Tedlar or aluminized Mylar bags, 100 liter capacity. To contain
sample.
5.3.4.1.5 Sample Bag Containers
Rigid leakproof containers for 5.3.4.1.4, with covering to protect
contents from sunlight.
5.3.4.1.6 Needle Valve
To adjust sample flow rate.
5.3.4.1.7 Pump—Leak—Free
Minimum capacity 2 liters per minute.
5.3.4.1.8 Charcoal Tube
To prevent admission of halogenated organics to the atmosphere in
the vicinity of samplers.
5.3.4.1.9 Flow Meter
For observing sample flow rate; capable of measuring a flow range
from 0.10 to 1.00 liters per minute.
5.3.4.1.10 Connecting Tubing
Teflon, 6.4 mm outside diameter, to assemble sample train (Figure
5-6).
5.3-4
-------
5.3.4.2 Sample Recovery
5.3.4.2.1 Tubing
Teflon, 6.4 mm outside diameter, to connect bag to gas chromatograph
sample loop. A new unused piece is employed for each series of bag samples
that constitutes an emission test, and is to be discarded upon conclusion of
analysis of those bags.
5.3.4.3 Analysis
5.3.4.3.1 Gas Chromatograph
With FID, potentiometric strip chart recorder and 1.0 to 2.0 ml
sampling loop in automatic sample valve. The chromatographic system shall
be capable of producing a response to 0.1 ppm of the halogenated organic
compound that is at least as great as the average noise level. (Response is
measured from the average value of the baseliine to the maximum of the wave-
form, while standard operating conditions are in use.)
5.3.4.3.2 Chromatographic Column
Stainless steel, 3.04 m x 3.2 mm, containing 20 percent SP-2100/0.1
percent Carbowax 1500 to 100/120 Supelcoport. Other columns can be used,
provided that the precision and accuracy of the analysis of standards are
not impaired. Information confirming that adequate resolutin of the halogen-
ated organic compound peak is accomplished should be available. Adequate
resolution is defined as an area overlap of not more than 10 percent of the
halogenated organic compound peak by an interferent peak. Calculation of
area overlap is explained in Appendix C, Supplement A: "Determination of
Adequate Chromotographic Peak Resolution."
5.3.4.3.3 Flow Meters (2)
Rotameter type, 0 to 100 ml/min capacity.
5.3.4.3.4 Gas Regulators
For required gas cylinders.
5.3.4.3.5 Thermometer
Accurate to one degree centigrade, to measure temperature of heated
sample loop at time of sample injection.
5.3-5
-------
5.3.4.3.6 Barometer
Accurate to 5 mm Hg, to measure atmospheric pressure around gas
chromatograph during sample analysis.
5.3.4.3.7 Pump—Leak-free
Minimum capacity 100 ml/min.
5.3.4.3.8 Recorder
Strip chart type, optionally equipped with disc integrator or elec-
tronic integrator.
5.3.4.3.9 Planimeter
Optional, in place of disc or electronic integrator, for Section
5.3.4.3.8 to measure chromatograph peak areas.
5.3.4.4 Calibration
Sections 5.3.4.4.2 through 5.3.4.4.6 are for Section 5.3.7.1
which is optional.
5.3.4.4.1 Tubing
Teflon, 6.4 mm outside diameter, separate pieces marked for each
calibration concentration.
5.3.4.4.2 Tedlar or Aluminized Mylar Bags
50-liter capacity, with valve; separate bag marked for each calibra-
tion concentration.
5.3.4.4.3 Syringe
25//,l, gas tight, individually calibrated, to dispense liquid halo-
genated organic solvent.
5.3.4.4.4 Syringe
50/il, gas tight, individually calibrated, to dispense liquid halo-
genated organic solvent.
5.3.4.4.5 Dry Gas Meter, With Temperature and Pressure Gauges
Accurate to +_ 2 percent, to aeter nitrogen in preparation of stan-
dard gas mixtures, calibrated at the flowrate used to prepare standards.
5.3-6
-------
5.3.4.4.6 Midget Impinger/Hot Plate Assembly
To vaporize solvent.
5.3.5 Reagents
It is necessary that all reagents be of chromatographic grade.
5.3.5.1 Analysis
5.3.5.1.1 Helium Gas or Nitrogen Gas
Zero grade, for chromatographic carrier gas.
5.3.5.1.2 Hydrogen Gas
Zero grade.
5.3.5.1.3 Oxygen Gas or Air as Required by the Detector
Zero grade.
5.3.5.2 Calibration
Use one of the following options: either 5.3.5.2.1 or 5.3.5.2.2, or
5.3.5.2.3.
5.3.5.2.1 Halogenated organic compound
99 mol percent pure, certified by the manufacturer to contain a
minimum of 99 mol percent of the particular halogenated organic compounds;
for use in the preparation of standard gas mixtures as described in Section
5.3.7.1.
5.3.5.2.2 Nitrogen Gas
Zero grade, for preparation of standard gas mixtures as described
in Section 5.3.7.1.
5.3.5.2.3 Cylinder Standards (3)
Gas mixture standards (200, 100, and 50 ppm of the halogenated or-
ganic compound of interest, in nitrogen) for which the gas composition has
been certified with an accuracy of + 3 percent or better by the manufacturer.
The manufacturer must have recommended a maximum shelf life for each cylinder
so that the concentration does not change by greater than +_ 5 percent from
the certified value. The date of gas cylinder preparation, certified concen-
tration of the halogenated organic compound and recommended maximum shelf
5.3-7
-------
life must have been affixed to the cylinder before shipment from the gas
manufacturer to the buyer. These gas mixture standards may be directly used
to prepare a chromatograph calibration curve as described in Section 5.3.7.2.2.
5.3.5.2.3.1 Cylinder Standards Certification
The concentration of the halogenated organic compound in nitrogen
in each cylinder must have been certified by the manufacturer by a direct
analysis of each cylinder using an analytical procedure that the manufacturer
had calibrated on the day of cylinder analysis. The calibration of the analy-
tical procedure shall, as a minimum, have utilized a three-point calibration
curve. It is recommended that the manufacturer maintain two calibration
standards and use these standards in the following way: (1) a high concentra-
tion standard (between 200 and 400 ppm) for preparation of a calibration
curve by an appropriate dilution technique; (2) a low concentration standard
(between 50 and 100 ppm) for verification of the dilution technique used.
If the difference between the apparent concentration read from the cali-
bration curve and the true concentration assigned to the low concentration
standard exceeds 5 percent of the true concentration, determine the source
of error and correct it, then repeat the three-point calibration.
5.3.5.2.3.2 Establishment and Verification of Calibration Standards
The concentration of each calibration standard must have been esta-
blished by the manufacturer using reliable procedures. Additionally, each
calibration standard must have been verified by the manufacturer by one of
the following procedures, and the agreement between the initially determined
concentration value and the verification concentration value must be within
+ 5 percent: (1) verification value determined by comparison with a gas mix-
ture prepared in accordance with the procedure described in Section 5.3.7.1.1
and using 99 mol percent of the halogenated organic compounds, or (2) verifi-
cation value obtained by having the calibration standard analyzed by the
National Bureau of Standards, if such analysis is available. All calibration
standards must be reverfied on a time interval consistent with the shelf
life of the cylinder standards sold.
5.3.5.2.4 Audit Cylinder Standards (2)
Gas mixture standards identical in preparation to those in Section
5.3.5.2.3 (the halogenated organic compounds of interest, in nitrogen),
5.3-8
-------
except the concentrations are only known to the person supervising the analy-
sis of samples. The concentrations of the audit cylinders should be: one
low concentration cylinder in the range of 25 to 50 ppm, and one high concen-
tration cylinder in the range of 200 to 300 ppm. When available, audit
cylinders may be obtained by contacting: EPA, Environmental Monitoring and
Support Laboratory, Quality Assurance Branch (MD-77), Research Triangle
Park, North Carolina 27711. If audit cylinders are not available at EPA, an
alternate source must be secured.
5.3.6. Procedure
5.3.6.1 Sampling
Assemble the sample train as in Figure 5-6. Perform a bag leak
check according to Section 5.3.7.3.2. Join the quick connects as illustrated,
and determine that all connections between the bag and the probe are tight.
Place the end of the probe at the centroid of the stack and start the pump
with the needle valve adjusted to yield a flow of 0.5 1pm. After a period
of time sufficient to purge the line several times has elapsed, connect the
vacuum line to the bag and evacuate the bag until the rotameter indicates no
flow. At all times, direct the gas exiting the rotameter away from sampling
personnel. Then reposition the sample and vacuum lines and begin the actual
sampling, keeping the rate constant. At the end of the sample period, shut
off the pump, disconnect the sample line from the bag, and disconnect the
vacuum line from the bag container. Protect the bag container from sunlight.
5.3.6.2 Sample Storage
Sample bags must be kept out of direct sunlight and must be
protected from heat. Analysis must be performed within 1 day of sample
collection for methylene chloride, ethylene dichloride and trichlorotrifluor-
oethane. Analysis of perchloroethylene, trichloroethylene, 1,1,1-trichloroe-
thane and carbon tetrachloride must be performed within 2 days.
5.3.6.3 Sample Recovery
With a new piece of Teflon tubing identified for that bag,
connect a bag inlet valve to the gas chromatograph sample valve. Switch the
valve to receive gas from the bag through the sample loop. Arrange the
equipment so the sample gas passes from the sample valve to a 0-100 ml/min
rotameter with flow control valve followed by a charcoal tube and a 0-1 inch
5.3-9
-------
w.g. pressure gauge. Sample flow may be maintained either by a vacuum pump
or container pressurization if the collection bag remains in the rigid con-
tainer. After sample loop purging is ceased, allow the pressure gauge to
return to zero before activating the gas sampling valve.
5.3.6.4 Analysis
Set the column temperature to 100°C, and the detector tempera-
ture to 225°C. When optimum hydrogen and oxygen flow rates have been deter-
mined, verify and maintain these flow rates during all chromatograph opera-
tions. Using zero helium or nitrogen as the carrier gas, establish a flow
rate in the range consistent with the manufacturer's requirements for satis-
factory detector operation. A flow rate of approximately 20 ml/min should
produce adequate separations. Observe the base line periodically and deter-
mine that the noise level has stabilized and that base line drift has ceased.
Purge the sample loop for thirty seconds at a rate of 100 ml/min, then acti-
vate the sample valve. Record the injection time (the position of the pen
on the chart at the time of sample injection), the sample number, the sample
loop temperature, the column temperature, carrier gas flow rate, chart
speed and the attenuator setting. Record the laboratory pressure. From the
chart, note the peak having the retention time corresponding to the halogen-
ated organic compound peak as determined in Section 5.3.7.2.1. Measure the
halogenated organic compound peak area, Am, by use of a disc integrator,
electronic integrator, or a planimeter. Record Am and the retention time.
Repeat the injection at least two times or until two consecutive values for
the total area of the peak do not vary more than 5 percent. The average
value for these two total areas will be used to compute the bag concentration.
5.3.6.5 Determine Ambient Conditions
Measure the ambient temperature and barometric pressure near
the bag. From a water saturation vapor pressure table, determine and record
the water vapor content of the bag as a decimal figure. (Assume the relative
humidity to be 100 percent unless a lesser value is known.)
5.3.7 Standards, Calibration, and Quality Assurance
5.3.7.1 Standards
5.3-10
-------
5.3.7.1.1 Preparation of Standard Gas Mixtures
(Optional-delete if cylinder standards are used.) Assemble the
apparatus shown in Figure 5-7. Check that all fittings are tight. Evacuate
a 50-liter Tedlar or aluminized Mylar bag that has passed a leak check (de-
scribed in Section 5.3.7.3.2) and meter in about 50 liters of nitrogen.
Measure the barometric pressure, the relative pressure at the dry gas meter,
and the temperature at the dry gas meter. Refer to Table 5-2. While the
bag is filling, use the 50 yu,l syringe to inject through the septum on top of
the impinger, the quantity required to yield a concentration of 200 ppm. In
a like manner, use the 25 ju,l syringe to prepare bags having approximately
100 and 50 ppm concentrations. To calculate the specific concentrations,
refer to Section 5.3.8.1. Tedlar bag gas mixture standards of methylene
chloride, ethylene dichloride, and trichlorotrifluoroethane may be used for
1 day; trichloroethylene and 1,1,1-trichloroethane for 2 days; perchloroethy-
lene and carbon tetrachloride for 10 days from the date of preparation.
(Caution: Contamination may be a problem when a bag is reused if the gas
mixture standard is a lower concentration than the previous gas mixture
standard.)
5.3.7.2 Calibration
5.3.7.2.1 Determination of Halogenated Organic Compound Retention
Time
This section can be performed simultaneously with Section 5.3.7.2.2.
Establish chromatograph conditions identical with those in Section 5.3.6.3
above. Determine proper attenuator position. Flush the sampling loop with
zero helium or nitrogen and activate the sample valve. Record the injection
time, the sample loop temperature, the column temperature, the carrier gas
flow rate, the chart speed and the attenuator setting. Record peaks and
detector responses that occur in the absence of the halogenated organic.
Maintain conditions (with the equipment plumbing arranged identically to
Section 5.3.6.3), flush the sample loop for 30 seconds at the rate of 100 ml/
min with one of the halogenated organic compound calibration mixtures, and
activate the sample valve. Record the injection time. Select the peak that
corresponds to the halogenated organic compound. Measure the distance on
5.3-11
-------
TEFLON 7
TUBING /
WATER
MANOMETER
I
M
S3
MIDGET
IMPINGER
THERMOMETER
SYRINGE
l
SEPTUM
BOILING WATER
BATH
INTEGRAL
VALVE
HOT PLATE
-TEDLAR BAG
CAPACITY 50 LITERS
ZERO AIR
CYLINDER
Mgure 5-7. Apparatus for the Preparation of Calibration Gas Mixtures from Liquid Solvent
-------
TABLE 5-2
OJ
INJECTION VALUES FOR PREPARATION OF STANDARDS
(Optional, See Section 5.3.7.1.1)
Compound
Perchloroethylene C2C14
Trichloroethylene C2HC13
1,1,1-Trichloroethane C2H3C13
Methylene Chloride CH2C12
Trichlorotrifluoroethane C2C13F3
Carbon Tetrachloride CC14
Ethylene Dichloride CoHAClo
Molecular Wt.
(M)
165.85
131.40
133.42
84.94
187.38
153.84
98.96
fil. Liquid Required in 50 1 N2
Density at 293° K for Approximate Concentration of:
(D) 200 ppm 100 ppm 50 ppm
1.6230
1.4649
1.4384
1.3255
1.5790
1.5940
1.2569
42.5
37.3
38.6
26.6
49.3
40.1
32.7
21.2
18.6
19.3
13.3
24.7
20.1
16.4
10.6
9.3
9.6
6.7
12.3
10.0
8.2
-------
the chart from the injection time to the time at which the peak maximum oc-
curs. This distance divided by the chart speed is defined as the halogenated
organic compound peak retention time. Since it is possible that there will
be other organics present in the sample, it is very important that positive
identification of the halogenated organic compound peak be made*
5.3.7.2.2 Preparation of Chromatograph Calibration Curve
Make a gas chromatographic measurement of each standard gas mixture
(described in Section 5.3.5.2.3 or 5.3.7.1.1) using conditions identical
with those listed in Sections 5.3.6.3 and 5.3.6.4. Flush the sampling loop
for 30 seconds at the rate of 100 ml/min with one of the standard gas mixtures
and activate the sample valve. Record Cc, the concentration of halogenated
organic injected, the attenuator setting, chart speed, peak area, sample
loop temperature, column temperature, carrier gas flow rate, and retention
time. Record the laboratory pressure. Calculate Ac, the peak area multiplied
by the attenuator setting. Repeat until two consecutive injection areas are
within 5 percent, then plot the average of those two values versus Cc. When
the other standard gas mixtures have been similarly analyzed and plotted,
draw a straight line through the points. Perform calibration daily, or be-
fore and after each set of bag samples, whichever is more frequent.
5.3.7.3 Quality Assurance
5.3.7.3.1 Analysis Audit
Immediately after the preparation of the calibration curve and
prior to the sample analyses, perform the analysis audit described in Appen-
dix C, Supplement B: "Procedure for Field Auditing GC Analysis."
5.3.7.3.2 Bag Leak Checks
While performance of this section is required subsequent to bag
use, it is also advised that it be performed prior to bag use. After each
use, make sure a bag did not develop leaks as follows: to leak check, connect
a water manometer and pressurize the bag to 5-10 cm 1^0 (2-4 in. 1^0).
Allow to stand for 10 minutes. Any displacement in the water manometer
indicates a leak. Also, check the rigid container for .leaks in this manner.
(Note: an alternative leak check method is to pressurize the bag to 5-10 cm
H20 or 2-4 in. 1^0 and allow to stand overnight. A deflated bag indicates
a leak.) For each sample bag in its rigid container, place a rotameter in
5.3-14
-------
line between the bag and the pump inlet. Evacuate the bag* Failure of the
rotameter to register zero flow when the bag appears to be empty indicates a
leak.
5.3.8. Calculations
5.3.8.1 Optional Standards Concentrations
Calculate each halogenated organic standard concentration prepared
in accordance with Section 5.3.7.1.1 as follows:
(B/ul) /D//g\ /103Atg\ /Ag-mole\ /24.055A<1\(106)
I /*!'' mg ; I M jag / l/Ag-mole '
m
J*P_ (24.055 x 103)
M Equation 5-3
293 P
V v -=Jn-
vm Y Tm 760
Where:
Cc - Standard concentration in ppm.
B - Number of /il injected.
Vm " Gas volume measured by dry gas meter in liters.
Y = Dry gas meter calibration factor.
Pm • Absolute pressure of the dry gas meter, mm Hg.
Tm = Absolute temperature of the dry gas meter, °K.
D = Density of compound at 293° K.
M - Molecular weight of compound.
24.055 = Ideal gas constant at 293° K, 760 mm Hg.
10" » Conversion factor, ppm.
5.3.8.2 Sample Concentrations
From the calibration curve described in Section 5.3.7.2.2 above,
select the value of Cc that corresponds to Ac. Calculate Cg as follows:
5.3-15
-------
CcPrTl
C - c r i
s PiTj. (l-Swb) Equation 5-4
Where: Sw^) = The water vapor content of the bag sample, as analyzed.
Cs = The concentration of the halogenated organic in the sample in ppm.
Cc = The concentration of the halogenated organic indicated by the gas
chromatograph, in ppm.
Pr = The reference pressure, the laboratory pressure recorded during
calibration, mm Hg.
T^ = The sample loop temperature on the absolute scale at the time of
analysis, °K.
P£ = The laboratory pressure at time of analysis, mm Hg.
Tr = The reference temperature, the sample loop temperature recorded
during calibration, °K.
5.3.9. References
1. Feairheller, W. R., Kemmer, A. M., Warner, B. J., and D. Q. Doug-
las. "Measurement of Gaseous Organic Compound Emissions by Gas Chromato-
graphy," EPA Contract No. 68-02-1404, Task 33 and 68-02-2818, Work Assignment
3. January 1978. Revised August, 1978, by EPA.
2. Bulletin 747. "Separation of Hydrocarbons" 1974. Supelco, Inc.
Bellefonte, Pennsylvania 16823.
3. Communication from Joseph E. Knoll. Perchloroethylene Analysis
by Gas Chromatography. March 8, 1978.
4. Communication from Joseph E. Knoll. Test Method for Halogenated
Hydrocarbons. December 20, 1978.
5.3-16
-------
5.4 MATERIAL BALANCE
A material balance test provides data to quantify the amount of
solvent input into a degreaser over a sufficiently long time period so that
an average emission rate can be calculated. This technique is useful where
pounds per hour or pounds per day emission limitations are applicable, such
as with "Rule 66" type regulations. It may also be useful when an accurate
plant site emissions inventory is required.
In order to perform a material balance test, the following general
procedure should be used:
1. Fill the solvent sump (or bath) to a marked level.
2. Begin normal operation of the degreaser, recording the quantity
of make-up solvent and hours of operation.
3. Conduct the test for about four weeks, or until the solvent
loss is great enough to minimize the error in measurement.
4. Refill the solvent sump to the original, marked level, record-
ing the volume of solvent added. The total volume of solvent
added during the test period approximately equals the solvent
emitted.
Degreasers that are used in manufacturing operations are in service
often enough such that it is necessary to drain the contaminated solvent
from the sump and recharge it with clean solvent. Under these circumstances
this cycle (often approximately one week) is long enough to minimize measure-
ment errors.
Marking the sump liquid level is generally impractical in open top
and conveyorized degreasers due to safety problems (exposure to high solvent
concentrations and heat) and accessability. An alternative for open top
vapor degreasers is to use a dip stick to record the solvent level. The
stick should be made of a nonabsorbent material such as metal and care should
be taken not to disturb the air/vapor interface if the sump heat is on. Also,
precautions should be taken in handling the hot dip stick. For conveyorized
5.4-1
-------
degreasers the manufacturer's instruction manual should be consulted for
topping off the sump. This may also be necessary for very large open top
vapor degreasers.
Although a highly accurate material balance is not usually neces-
sary, the following modifications will improve the accuracy of the test.
1. Clean the degreaser sump before testing.
2. Record the amount of solvent added to the tank with a flow meter.
3. Record the weight and type of work load degreased each day.
4. At the end of the test run, pump out the used solvent and mea-
sure the amount with a flow meter. Also, approximate the volume
of metal chips and other material remaining in the emptied
sump, if significant.
5. Bottle a sample of the used solvent and analyze it to find the
percent that is oil and other contaminants. The oil and solvent
proportions can be estimated by weighing samples of used solvent
before and after boiling off the solvent. Calculate the volume
of oils in the used solvent. The volume of solvent displaced
by this oil along with the volume of make-up solvent added
during operations is equal to the solvent emisison.
Proper maintenance and adjustment should be performed on the de-
greaser and control system before the test period.
Figure 5-8 illustrates an example material balance data sheet.
The control official or degreaser operator is encouraged to develop a data
sheet that is specific to the particular test being conducted.
5.4-2
-------
Figure 5-8. Material Balance Data Sheet
1. BUSINESS LICENSE NAME OF CORPORATION, COMPANY, OR INDIVIDUAL OWNER OR GOVERNMENTAL AGENCY:
2a. MAILING ADDRESS
3. SOURCE NO. (PERMIT NUMBER, NEDS ID., ETC.)
2b. PLANT ADDRESS WHERE THIS DECREASER IS LOCATED
4. NAME AND TITLE OF AUTHORIZED COMPANY REPRESENTATIVE FURNISHING DATA: SIGNATURE:
5. TELEPHONE NO.:
6. DEGREASER
MANUFACTURER:
MODEL NO.
INSIDE DIMENSIONS OF TANK (FT):
WIDE X
_SERIAL NO.
LONG X
DEEP
MATERIAL BALANCE DATA
7. BEFORE BEGINNING OPERATION FILL THE CLEANED SOLVENT SUMP TO A MARKED LEVEL AND NOTE APPROXIMATE DISTANCE
FROM TOP EDGE OF TANK.
DISTANCE FROM TOP EDGE OF TANK ' INCHES
8. BEGIN NORMAL OPERATION OF DEGREASER AND RECORD HOURS OF OPERATION AND MAKE UP SOLVENT ON CHART
OF OPERATION
MAKE UP SOLVENT
DATE TIME
DATE
TIME
TOTAL HOURS OPERATED
DATE ADDED
NUMBER OF GALLONS
TOTAL GALLONS ADDED
OPERATE UNIT FOR SEVERAL WEEKS OR UNTIL SOLVENT MUST BE CHANGED DUE TO CONTAMINATION. HALT OPERATION
AND REFILL SOLVENT SUMP TO ORIGINAL MARKED LEVEL: RECORD VOLUME OF SOLVENT ADDED.
VOLUME OF SOLVENT ADDED AFTER OPERATION HALTED GALLONS
10. TOTAL VOLUME OF SOLVENT USED (ADD 8 & 9)
TOTAL TIME OF RUN
GALLONS
HOURS
11. IF SIGNIFICANT, ESTIMATE THE VOLUME OF METAL CHIPS AND OTHER MATERIAL ACCUMULATED IN THE SUMP:
5.4-3
-------
APPENDIX A
LIST OF REFERENCES
-------
SOLVENT METAL CLEANING PROCESSES
LIST OF REFERENCES
1. ASTM, D-26: Handbook of Vapor Degreasing, ASTM Special Technical
Publication 310A, Philadelphia, Pa., April 1976.
2. DOW Chemicals, USA: Modern Vapor Degreasing and DOW Chlorinated
Solvents. Form No. 100-5185-77.
3. Diamond-Shamrock Corp., Electro Chemicals Division: Vapor Degreasing
Handbook. EC-S-512.
4. Surprenant, K.S., Richards, D.W., "Study to Support New Source Per-
formance Standards for Solvent Metal Cleaning Operations", Dow Chemi-
cal Company (EPA Contract 68-02-1329, Task Order No. 9), June 30, 1979.
5. Massoglla, M.F., "Industry Characterization and Required Effort to
Control VOC Emissions: Solvent Metal Cleaning Processes", Research
Triangle Institute (EPA Contract 68-01-4141, Task Order No. 16),
December 1978.
6. Danielson, J.A. (ed.), "Air Pollution Engineering Manual", EPA Publica-
tion AP-40, May 1973.
7. "Control of Volatile Organic Emissions from Solvent Metal Cleaning",
Emission Standards and Engineering Division, U.S. Environmental Pro-
tection Agency, EPA Publication EPA-450/2-77-022, November 1977.
8. "Handbook of Organic Industrial Solvents", National Association of
Mutual Casualty Companies, Chicago, Illinois, 1958.
9. Rhoades, R.G., Memorandum to Directors, Air & Hazardous Materials
Division, Regions I, III-X, and Director, Environmental Programs
Division, Region II, Subject: Clarification of Degreasing Regulation
Requirements, September 7, 1978.
10. "Vapor Degreasing Handbook", Diamond Shamrock Corporation.
11. "Vapor Degreasing With Chlorinated Solvents" Ethyl Corporation, Indus-
trial Chemicals Division
12. "Conveyorized Degreasers", Bulletin 2172.1
"Cold Trap", Bulletin 2141.9
"Heavy-Duty Solvent Recovery Stills", Bulletin 2112.12
"Three Dip Degreaser", Bulletin 2114.11
"Liquid-Liquid-Vapor Type", Bulletin 2171.1
"Carbon Adsorption Systems", Bulletin 2141.8
"Immersion/Spray Degreasers with Ultrasonic Option", Bulletin 2113.16
"Vapor Spray Degreaser, Bulletin 2114.1
"Solvent Cleaning Systems", Bulletin 2172.2
"Liquid Vapor Degreaser", Bulletin 2114.18
Baron-Blakeslee, Inc., Chicago, Illinois
A-l
-------
13. "Perchlorethylene", Bulletin 35C
"Trichlorethylene", Bulletin 35B
"Tri-Ethane", Bulletin 35A
PPG Industries, Inc., Pittsburgh, PA
14. Pendleton, G., Kleer Flo Company, personal communication, March 9, 1979
15. "Vapor Spray Degreaser, Model DH"
"Vapor Spray Degreaser, Model NP"
"Vapor Spray Degreasers, Model DM"
Delta Industries, Santa Fe Springs, CA
A-2
-------
APPENDIX B
CTG GUIDELINES
-------
CONTROL SYSTEMS FOR COLD CLEANING
Control System A
Control Equipment
1. Cover
2. Facility for draining cleaned parts
3. Permanent, conspicuous label, summarizing the operating requirements
Operating Requirements:
1. Do not dispose of waste solvent or transfer it to another party,
such that greater than 20 percent of the waste (by weight) can evaporate
into the atmosphere.* Store waste solvent only in covered containers.
2. Close degreaser cover whenever not handling parts in the cleaner.
3. Drain cleaned parts for at least IS seconds or until dripping ceases.
Control System B
Control Equipment:
1. Cover: Same as in System A, except if (a) solvent volatility is
greater than 2 kPa (15 mm Hg or 0.3 psi) measured at 38°C (100°F),**
(b) solvent is agitated, or (c) solvent is heated, then the cover must
be designed so that it can be easily operated with one hand. (Covers for
larger degreasers may require mechanical assistance, by spring loading,
counterweighting or powered systems.)
2. Drainage facility: Same as in System A, except that if solvent
volatility is greater than about 4.3 kPa (32 mm Hg or 0.6 psi) measured at
38°C (100°F), then the drainage facility must be internal, so that parts are
enclosed under the cover while draining. The drainage facility may be
external for applications where an internal type cannot fit into the cleaning
system.
3. Label: Same as in System A
4. If used, the solvent spray must be a solid, fluid stream (not a
fine, atomized or shower type spray) and at a pressure which does not cause
excessive splashing.
5. Major control device for highly volatile solvents: If the solvent
volatility is > 4.3 kPa (33 mm Hg or 0.6 psi) measured at 38°C (100°F), or
if solvent is heated above 50°C (120°F), then one of the following control
devices must be used:
a. Freeboard that gives a freeboard ratio*** ^ 0.7
b. Water cover (solvent must be insoluble in and heavier than water)
c. Other systems of equivalent control, such as a refrigerated chiller
or carbon adsorption.
Operating Requirements:
Same .is in System A
*Water and .solid waste regulations must also be complied with.
**Ceneralty Holvcnts consisting primarily of mineral spirits (Stoddard) have
volatilities - 2 kPa.
***Freebonrd ratio is defined as the freeboard height divided by the width
of the dc'itrciiHcr.
B-l
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COMPLETE CONTROL SYSTEMS FOR OPEN TOP VAPOR DEGREASERS
Control System A
Control Equipment:
1. Cover that can be opened and closed easily without disturbing the vapor zone.
Operating Requirements:
1. Keep cover closed at all times except when processing work loads through
the degreaser.
2. Minimize solvent carry-out by the following measures:
a. Rack parts to allow full drainage.
b. Move parts in and out of the degreaser at less than 3.3 m/sec.(ll ft/min).
c. Degrease the work load in the vapor zone at least 30 sec. or until
condensation ceases.
d. Tip out any pools of solvent on the cleaned parts before removal.
e. Allow parts to dry within the degreaser for at least 15 sec. or until
visually dry.
3. Do not degrease porous or absorbent materials, such as cloth, leather, wood
or rope.
4. Work loads should not occupy more than half of the degreaser's open top area.
5. The vapor level should not drop more than 10 cm (4 in.) when the work load
enters the vapor zone.
6. Never spray above the vapor level.
7. Repair solvent leaks immediately, or shutdown the degreaser.
8. Do not dispose of waste solvent or transfer it to another party such that
greater than 20 percent of the waste (by weight) will evaporate into the
atmosphere. Store waste solvent only in closed containers.
1 2 '2
9. Exhaust ventilation should not exceed 20 m /min. per m (65 cfm per ft )
of degreaser open area, unless necessary to meet OSHA requirements. Ventilation
fans should not be used near the degreaser opening.
10. Water should not be visually detectable in solvent exiting the water separator.
Control System B
Control Equipment:
1. Cover (same as in system A).
2. Safety switches.
a. Condenser flow switch and thermostat - (shuts off sump neat if condenser
coolant is either not circulating or too warm).
b. Spray safety switch - (shuts off spray pump if the vapor level drops
excessively, about 10 cm (4 in).
3. Major Control Device:
Either: a. Freeboard ratio greater than or equal to 0.75, and if the degreaser
opening is >lm (10 f t ) , the cover must be powered,
b. Refrigerated chiller,
c. Enclosed design (cover or door opens only when the dry part is
actually entering or exiting the degreaser),
d. Carbon adsorption system, with ventilation >15 nr/min per m
(50 cfm/ft ) of air/vapor area (when cover is open), and exhausting
<25 ppm solvent averaged over one complete adsorption cycle, or
e. Control system, demonstrated to have control efficiency, equiva-
lent to or better than any of the above.
4. Permanent, conspicuous label, summarizing operating procedures 01 to 06.
Operating Requirement!):
Snmc an In System A
B-2
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CONTROL SYSTEMS FOR CONVEYORIZED DEGREASERS
Control Syatem A
Control Equipment: None
Operating Requirements:
1. Exhaust ventilation should not exceed 20 m'/min per oi2 (65 cfm per ft2) of degreaser opening.
unless necessary to meet OSHA requirements. Work place fans should not be used near the degreaser opening.
2. Minimize carry-out emissions by:
a. Racking parts for best drainage.
b. Maintaining verticle conveyor speed at < 3.3 m/mln (11 ft/nin).
3. Do not dispose of waste solvent or transfer it to another party such that greater than 20 percent
of the waste (by weight) can evaporate into the atmosphere. Store waste solvent only In covered containers.
4. Repair solvent leaks Immediately, or shutdown the degreaser.
5. Water should not be visibly detectable In the solvent exiting the water separator.
Control System B
Control Equipment:
1. Major control devices; the degreaser must be controlled by either:
a. Refrigerated chiller,
b. Carbon adsorption system, with ventilation _> IS m2/mln per m2 (50 cfm/ft2) of air/vapor area
(when down-time covers are open), and exhausting <25 ppm of solvent by volume averaged over a complete
adsorption cycle, or
c. System demonstrated to have control efficiency equivalent to or better than either of the above.
2. Either a drying tunnel, or another means such as rotating (tumbling) basket, sufficient to prevent
cleaned parts from carrying out solvent liquid or vapor.
3. Safety switches
a. Condenser flow switch and thermostat - (shuts off sump heat If coolant Is either not circulating
or too warm).
b. Spray safety switch - (shuts off spray pump or conveyor if the vapor level drops excessively,
e'.g. > 10 en (4 in)).
c. Vapor level control thermostat - (shuts off sump heat when vapor level rises too high).
4. Minimized openings: Entrances and exits should silhouette work loads so that the average clearance
(between parts and the edge of the degreaser opening) Is either <10 cm (4 In.) or <10 percent of the width
of the opening.
5. Down-time covers: Covers should be provided for closing off the entrance and exit during shutdown
hours.
Operating Requirements:
1. to 5. Same as for System A
6. Down-time cover must be placed over entrances and exits of conveyorized degreasers immediately after
the conveyor and exhaust are shutdown and removed just before they are started up.
B-3
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APPENDIX C
SUPPLEMENT A: DETERMINATION OF ADEQUATE
CHROMATOGRAPHIC PEAK RESOLUTION
SUPPLEMENT B; PROCEDURE FOR FIELD AUDITING
GC ANALYSIS
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SUPPLEMENT A
DETERMINATION OF ADEQUATE CHROMATOGRAPHIC PEAK RESOLUTION
In this method of dealing with resolution, the extent to which
one chromatographic peak overlaps another is determined.
For convenience, consider the range of the elution curve of
each compound as running from -2a to +2a. This range is used in
other resolution criteria, and it contains 95.45 percent of the
area of a normal curve. If two peaks are separated by a known
distance, b, one can determine the fraction of the area of one
curve that lies within the range of the other. The extent to which
the elution curve of a contaminant compounds overlaps the curve
of a compound that is under analysis is found by integrating the
contaminant curve over the limits b-2a to b+2a , where a is the
s s s
standard deviation of the sample curve.
There are several ways this calculation can be simplified.
Overlap can be determined for curves of unit area and then actual
areas can be introduced. The desired integration can be resolved
into two integrals of the normal distribution function for which
there are convenient calculation programs and tables. An example
would be Program 15 in Texas Instruments Program Manual ST1, 1975,
Texas Instruments Inc., Dallas, Texas 75222.
Jc dt =
b-2o.
x_
2
dx -
x_
2
dx.
C-1A
-------
The following calculation steps are required:*
1. 2ac = t//2 In 2
S S
2. a, = t 72/2 In 2
c c
3.
= (b-2as)/ac
4.
(b+2as)/cc
5.
dx
6. Q(x9) =
7. I.
i
_x_
2
dx
- Q(x2).
8' Ao = WAs
9. % overlap = AQ x 100
(Note: In most instances, Q(x2) is very small and may be neglected.)
C-2A
-------
Where:
A = The area of the sample peak of interest determined
by electronic integration, or by the formula AS • hstg.
A = The area of the contaminant peak, determined in the
c
same manner as Ag.
b = The distance on the chromatographic chart that
separates the maxima of the two peaks.
h = The peak height of the sample compound of interest,
measured from the average value of the baseline to
the maximum of the curve.
t = The width of the sample peak of interest at 1/2 of
peak height.
t = The width of the contaminant peak at 1/2 of peak
C
height.
0 = The standard deviation of the sample compound of
interest elution curve.
a = The standard deviation of the contaminant elution
curve.
Q(xJ • The integral of the normal distribution function from
X-, to infinity.
Q(x2) = The integral of the normal distribution function from
x2 to infinity.
I = The overlap integral.
A = The area overlap fraction
o
C-3A
-------
In judging the suitability of alternate gas chromatographic
columns, or the effects of altering chromatographic conditions,
one can employ the area overlap as the resolution parameter with
a specific maximum permissible value.
The use of Gaussian functions to describe chromatographic
elution curves is widespread. However, some elution curves are
highly asymetric. In those cases where the sample peak is
followed by a contaminant that has a leading edge that rises
sharply but the curve then tails off, it may be possible to
define an effective width for tc as "twice the distance from the
leading edge to a perpendicular line through the maxim of the
contaminant curve, measured along a perpendicular bisection of
that line."
C-4A
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SUPPLEMENT B
PROCEDURE FOR FIELD AUDITING GC ANALYSIS
Responsibilities of audit supervisor and analyst at the
source sampling site include the following:
A. Check that audit cylinders are stored in a safe location
both before and after the audit to prevent vandalism of same.
B. At the beginning and conclusion of the audit, record each
cylinder number and cylinder pressure. Never analyze an audit
cylinder when the pressure drops below 200 psi.
C. During the audit, the analyst is to perform a minimum
of two consecutive analyses of each audit cylinder gas. The audit
must be conducted to coincide with the analysis of source test
samples. Normally, it will be conducted immediately after the GC
calibration and prior to the sample analyses.
D. At the end of the audit analyses, the audit supervisor
requests the calculated concentrations from the analyst, and then
compares the results with the actual audit concentrations. If each
measured concentration agrees with the respective actual concentra-
tion within +_10 percent, he then directs the analyst to begin the
analysis of source samples. Audit supervisor judgment and/or
supervisory policy determines course of action when agreement is
not within +_ 10 percent. Where a consistent bias in excess of
10 percent is found, it may be possible to proceed with the sample
analyses, with a corrective factor to be applied to the results
at a later time. However, every attempt should be made to locate
the cause of the discrepancy, as it may be misleading. The audit
C-IB
-------
supervisor is to record each cylinder number, cylinder pressure
(at the end of the audit) and all calculated concentrations. The
individual being audited must not under any circumstance be told
the actual audit concentrations until the calculated concentrations
have been submitted to the audit supervisor.
C-2B
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FIELD AUDIT REPORT
PART A - To be filled out by organization supplying audit
cylinders
1. Organization supplying audit sample(s) and shipping address
2. Audit supervisor, organization, and phone number
3. Shipping instructions - Name, Address, Attention
4. Guaranteed arrival date for cylinders_
5. Planned shipping date for cylinders
6. Details on audit cylinders from last analysis
Low Cone. High Cone,
a. Date of last analysis
b. Cylinder number
c. Cylinder pressure, PSI
d. Audit gas(es)/balance gas
e. Audit gas(es) ppm
f. Cylinder construction
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PART B - To be filled out by audit supervisor
1. Process sampled
2. Location of audit
3. Name of individual audited
4. Audit date
5. Audit results
Low Cone. High Cone.
Cylinder Cylinder
a. Cylinder number
b. Cylinder pressure before
audit, psi
c. Cylinder pressure after
audit, psi
d. Measured concentration, ppm
Injection #1*
Injection #2*
Average *
e. Actual audit concentration, ppm
(Part A, 6e)
* Results of two consecutive injections which meet the sample
analysis criteria of the test method.
-------
f. Audit accuracy*
Low Cone. Cylinder
High Cone. Cylinder
* Percent accuracy = Measured Cone. - Actual Cone. x 10Q
Actual Cone.
g. Problems detected (if any)
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
DEPORT NO.
EPA-340/1-79-008
2.
3. RECIPIENT'S ACCESSION>NO.
TITLE AMD SUBTITLE
Inspection Source Test Manual for
Solvent Metal Cleaning (Degreasers)
. REPORT DATE
June 1979 fflal-P nf
6. PERFORMING ORGANIZATION CODE
AUTHOR(S)
Roger D. Allen
8. PERFORMING ORGANIZATION REPORT NO.
PERFORMING ORGANIZATION NAME AND ADDRESS
Engineering-Science
501 Willard Street
Durham, North Carolina 27701
10. PROGRAM ELEMENT NO.
11. CONtRACT/GRANT N6.
68-01-4146
2. SPONSORING AGENCY NAME AND ADDRESS
U.S. Environmental Protection Agency
Division of Stationary Source Enforcement
401 M Street SW
Washington, D.C. 20460
13. TYPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
5. SUPPLEMENTARY NOTES
Chapter authors are R. D. Allen, J. T. Chehaske,
T. A. Li Puma and J. Van Gieson
6. ABSTRACT
This document presents guidelines to enable field enforcement personnel to determine
whether solvent metal cleaning processes (degreasers) are in compliance with EPA's
guidelines for Reasonably Available Control Technology. Conveyorized degreasers,
open top vapor degreasers and cold cleaners are discussed. Principles of operation,
emissions points, parameters that effect emissions, emission control methods and field
investigation procedures are described. Suggested screening and compliance test
methods are provided. Inspection methods and types of records to be kept are dis-
cussed in detail.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
c. cos AT I Field/Group
Air Pollution
Solvent Metal Cleaning (Degreasing)
Emissions and Controls
Air Pollution Controls
Stationary Sources
Organic Vapors
Degreasing
13. DISTRIBUTION STATEMENT
Available from the National Technical
Information Service, 5285 Port Royal Road,
Springfield, Virginia 22161
19. SECURITY CLASS (ThisReport)
Unclassified
21. NO. OF PAGES
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
«U.S. GOVERNMENT PRINTING OFFICE: 1979 628-90:
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