Task Analysis of State and
Local Air Pollution Control Agencies and
Development of Staffing Guidelines
VOLUME
Detailed Task Data,and
Staffing Guidance
SOURCE
TESTING
UN I TED STATES
ENVIRONMENTAL PROTECTION AGENCY
Manpower Development Staff Office of Air Programs
Research Triangle Park, North Carolina 27711
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ss
United States
Environmental Protection Agency
Contract No. 68-02-0306
Applied Science
Associates, Inc.
Task Analysis of State and
Local Air Pollution Control Agencies and
Development of Staffing Guidelines
VOLUME
Detailed Task Data, and
Staffing Guidance
SOURCE TESTING
K. I. Rifkin, Senior Staff Scientist, ASA
R. L. Dueker, Staff Scientist, ASA
W. F. Diggins, Staff Scientist, ASA
F. C. Foss, Staff Scientist, ASA
' and
Michael Senew, Project Officer, USEPA
Prepared for the
United States Environmental Protection Agency
Manpower Development Staff
Office of Air Programs
Research Triangle Park, North Carolina 27711
November 1972
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This is not an official policy and standards
document. The opinions, findings, and conclusions
are those of the authors and not necessarily those
of the United States Environmental Protection Agency.
Every attempt has been made to represent the
present state of the art as well as subject areas
still under evaluation. Any mention of products,
or organizations, does not constitute endorsement
by the United States Environmental Protection Agency.
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INTRODUCTION
One of the pressing problems in the air pollution control effort at
Federal, state, and local levels is planning manpower requirements and
developing manpower resources. Questions are being asked such as, how
many people are needed, what kind of past experience and education should
they have, how should their jobs be structured, what do they need to know
to do their jobs, what special abilities do they need, and what kind of
training should they receive to do their jobs? These questions are
becoming increasingly meaningful as the control effort broadens with the
creation of more and more local agencies and as existing agencies in-
crease the scope and depth of their programs. Adequate answers are
required if progress is to continue toward the goal of clean air.
In order to begin to answer questions relevant to manpower planning
and development, a data base describing the tasks to be performed by
control agency personnel and the skills and knowledge they must have to
perform those tasks effectively must be available. Guidance concerning
the use of the data base in making staffing decisions must be prepared.
It is the purpose of this study to provide such a data base and the
appropriate guidance.
A. Obj ectives
The objectives of this project were the following:
1. To identify as great a proportion as possible of the
population ofitasks currently being performed by air
pollution control agency personnel at the state and
local level throughout the country.
2. To describe the identified tasks in terms of component
behaviors and the skills and knowledge required to perform
those behaviors.
3. To identify and describe categories of air pollution con-
trol agency personnel who would perform the tasks mentioned
above.
continued
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4. To structure and communicate the data which resulted
from achieving the above objectives in a form which could
be used by agency management in planning and developing
manpower resources.
B. General Project Overview
The project was performed in two phases. Phase I dealt with achieving
the first two project objectives, and resulted in the development of a
detailed data base describing the major tasks performed by agency personnel
in terms of the procedural components of the tasks and the skills and
knowledge required to perform them. Phase II dealt with achieving the
last two major objectives, and resulted in production of a guidance docu-
ment which integrates and structures data developed in Phase I and presents
it in a form designed to assist agency manpower developers.
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THIS IS VOLUME F
Additional books available are:
VOLUME A: Guidance and Supporting Information for Staffing and Training
Decisions in an Air Pollution Control Agency - Introduction
and Directions for Using These Guidelines
VOLUME B: Guidance and Supporting Information for Staffing and Training
Decisions in an Air Pollution Control Agency - Engineering
VOLUME C: Guidance and Supporting Information for Staffing and Training
Decisions in an Air Pollution Control Agency - Field Enforcement
VOLUME D: Guidance and Supporting Information for Staffing and Training
Decisions in an Air Pollution Control Agency - Laboratory Support
VOLUME E: Guidance and Supporting Information for Staffing and Training
Decisions in an Air Pollution Control Agency - Air Monitoring
and Meteorological Support
VOLUME G: Guidance and Supporting Information for Staffing and Training
Decisions in an Air Pollution Control Agency - Agency Management,
Program Development, and Public Information Support
AND
TECHNICAL REPORT:
Task Analysis of State and Local
Air Pollution Cqntrol Agencies, and
Development
of Staffing Guidelines
For complete sets, or individual titles, or the Technical
Report please address your request to:
United States Environmental Protection Agency
Manpower Development Staff
Research Triangle Park, N. C. 27711
F-l
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SOURCE TESTING
The task data and staffing guidance presented in this volume
cover tasks which are generally performed by Engineers or Equipment
Technicians in connection with the agency's source testing effort.
The tasks included in this volume deal with both stationary and
mobile sources.
This volume covers the following source testing activities:
1. Performance of a Stack Test Page F-3
t
2. Managing a Stack Test Page F-10
3. Determination of Odor Concentration
in the Atmosphere or in Stack
Emissions Page F-19
A. Performing a Used Car Inspection Page F-23
5. Performing the Idle and ACID
Tests Page F-27
6. Planning the Dynamometer
Installation Page F-30
7. Operation and Maintenance of the
Engine Dynamometer Page F-35
8. Operation and Maintenance of the
Chassis Dynamometer Page F-42
F-2
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Performance of a Stack Test
ask Overview
here are more variations of stack testing methods than there are air
ollution control agencies. Some variations result from different
:inds of testing situations; others appear to be a function of the
ixperlence of individual stack testers. Basically, however, all stack
:ests for participate and/or gaseous concentration follow the general
procedure that is briefly described below:
1. Measurement of the gas flow. A stack test must be performed
isokinetically, that is, the sampling rate must equal the rate
of flow of the stack gas. Therefore, before a sample is collected
the gas flow must be measured. This includes determining the gas
velocity; the static pressure inside the stack; and the tempera-
ture, moisture content, and density of the gas.
2. Assembly and operation of the sampling train. The sampling train
must contain the following elements:
a. Sampling nozzle.
b. Participate sample collection device (e.g., impinger,
filter).
c. Gas sampling device (e.g., absorber).
d. Sampling probe.
e. Condenser or moisture trap.
f. Gas meter for measuring volume of sample.
g. Pump, or some other air-moving device.
h. Appropriate temperature and pressure Indicators.
There are many possible variations within the basic structure of
this train but this activity requires assembling the train according
to plan using laboratory prepared impingers and dry collectors, deter-
mining sampling nozzle size and sampling flow rate and conducting the
••mpling procedure as planned. Isokinetic conditions must be
F-3
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maintained throughout the test and all test parameters must be
periodically monitored and recorded.
3. Returning sampling apparatus and data records to the laboratory
for analysis.
Occupational Category; Equipment Technician
Task Description
The skill and knowledge analysis of this task is based on a con-
glomeration of all of the variations encountered in the air pollution
control agencies. However, each of these variations is also contained
in one or more of the task descriptions presented in the publications
cited at the end of this analysis (References 1, 2, 4, 5, 6, 7, 10, and
11). The remainder of the publications listed (References 3, 8, and 9)
contain useful information with regard to stack testing equipment and
selected testing techniques.
Skill Requirements
1. Ability to assemble sampling apparatus with each component in
proper sequence using butt-to-butt connections, tygon tubing,
and silicone or florocarbon grease as appropriate to create
a leak-proof assembly.
2. Ability to operate sampling apparatus or analyzer, making quick
and accurate adjustments in flow control devices in order to
maintain a predetermined sample flow rate and terminating
the sampling process precisely at a predetermined time.
3. Ability to read indicating devices, such as a thermometer,
manometer, dry gas meter, and flowmeter, and to interpret
meter readings against a calibration plot as required.
4. Ability to quickly and correctly solve an algebraic equation'
in several unknowns using a detailed step-by-step procedure.
Such equations include:
a. Calculating the concentration of a pollutant given the
sample absorbance reading and the calibration curve.
F-4
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b. Converting the volume of gas samples to the volume at
standard temperature and pressure using the perfect gas
equation.
5. Ability to read and interpret data from a table, psychometric
chart, or a nomograph.
6. Ability to accurately read, operate, calibrate, and otherwise
maintain the instruments required for measuring the velocity
pressure, static pressure, temperature, moisture content, and
composition of stack gases. (See Knowledge 3 for a complete list
of instruments).
7. Ability to quickly and accurately perform calculations of the
type which must be performed during a stack test; for example,
the calculation of the meter rate and sampling nozzle size.
Knowledge Requirements
1. Knowledge of the apparatus required for the task and how it
is configured.
2. Knowledge of the task procedure with all steps in their proper
sequence.
3. Knowledge of the nomenclature, configuration, and use of
instruments including:
a. Pitot tube (standard)
b. Type S pitot tube
i
c. Inclined manometer
d. Draft gauge
e. Micromanometer
f. Thermo-anemometer
g. Vane anemometer
h. Thermocouple and potentiometer
i. Mercury bulb thermometer
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j. Water gauge manometer
k. U-tube mercury manometer
1. Condenser
m. Wet- and dry-bulb thermometers
n. Orsat apparatus
4. Knowledge of the nomenclature, configuration, and use of the
apparatus required for collecting a stack gas particulate and
gaseous samples, including:
a. Sampling nozzle, e.g., gooseneck nozzle
b. Alundum thimble and holder
c. Flat filters and holders
d. Glass wool filter tube
e. Sampling probe
f. Condenser
g. Dry test meter
h. Gas flowmeter
i. Orifice meter
j. Rotameter
k. Pumps, e.g., rotary positive displacement pump
1. Aspirator
m. Impingers (Smith-Greenberg type)
n. Thermome ters
o. Pressure gauges, e.g., manometer
p. Paper thimble and holder
5. Knowledge of the procedure for conducting a velocity traverse.
6. Knowledge of the techniques for marking a pitot tube or sampling
probe in order to position the tube or probe at each of the
sampling points.
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7. Knowledge of the procedure for grounding a pitot tube (or sampling
probe) in the case of sampling near an electrostatic precipitator.
8. Knowledge of the proper technique for measuring the temperature
of stack gases.
9. Knowledge of the procedure for measuring the static pressure
inside a stack.
10. Knowledge of the procedure for calculating the absolute pressure
of a stack, given the static pressure of the stack and the
barometric pressure.
11. Knowledge of the procedure for determining the moisture content
of stack gases, using either a condenser or wet- and dry-bulb
thermometers.
12. Knowledge of precautions that must be taken with regard to hazards,
such as platform height, high temperature of stack and gases, and
electrical charges.
13. Knowledge of the procedure for conducting the stack sampling.
This includes knowledge of the technique for:
a. Inserting the probe.
b. Operating sampling apparatus.
c. Moving the probe from one point to another.
d. Recording times, temperatures, pressures, meter rates, etc.
e. Removing the probe without losing any of the sample.
14. Knowledge of procedure for draining the sampling train of moisture
and measuring the condensate.
15. Knowledge of the procedure for calculating the size of the
sampling nozzle required.
16. Knowledge of the service, maintenance, and calibration
requirements of all stack test instruments normally employed.
F-7
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References
1. American Society for Testing and Materials. Standard method for
sampling stacks for particulate matter. Philadelphia: Author,
1971. D2928-71.
2. American Society of Mechanical Engineers. Determining dust con-
centration in a gas stream. New York: Author, 1957.
3. Committee on Industrial Ventilation. Industrial ventilation. A
manual of recommended practice. Lansing, Michigan: American
Conference of Governmental Industrial Hygienists, 1970 (llth
Edition), pp. 9(1-8).
4. Devorkin, H., Chass, R., Fudurich, A., & Kanter, C. R. Holmes
(Ed.) Air pollution source testing manual. Los Angeles: Air
Pollution Control District, Los Angeles County, November 1965.
5. Environmental Protection Agency. Standards of performance for
new stationary sources. Federal Register, Volume 36, Number 159,
August 17, 1971.
6. Haaland, H. H. (Ed.) Methods for determination of velocity.
dust and mist content of gases. Bulletin WP-50. Seventh
Edition. Los Angeles: Western Precipitation Division/Joy
Manufacturing Company, 1968.
7. Jacobs, M. B. The chemical analysis of air pollutants. New
York: Interscience Publishers, Inc., 1960. pp. 140-155.
8. Joy Manufacturing Company, Western Precipitation Division.
Gas velocity and dust determination equipment. Catalog GV22.
Los Angeles: Author.
9. Kimura, G. Emission control of flue-fed incinerators by use of
air pollution control devices. Chicago: Department of Air
Pollution Control, City of Chicago, November 1969. pp. 87-90.
10. PEDCo-Environmental Specialists, Inc. Administrative and
technical aspects of source sampling for particulates. Contract
No. CPA 70-124. Research Triangle Park, North Carolina:
Environmental Protection Agency, May 1971.
F-8
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f:
11. Weisburd, M. (Ed.) Air pollution control field operations
manual. A guide for inspection and enforcement. Washington,
D. C.: U. S. Department of Health, Education, and Welfare;
Public Health Service, Division of Air Pollution, 1962. PHSP #937.
pp. 167-176.
F-9
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Managing a Stack Test
Task Overview
Managing a stack test is usually an engineering function although, since
the test usually involves the laboratory analysis of gaseous and partic-
ulate pollutants, a chemist may participate in test planning. The
general procedure for managing a stack test is as follows:
1. Obtain the cooperation of plant personnel. This involves elicit-
ing voluntary cooperation from high level management for the
conduct of the test and collecting information about the in-
t
dustrial process being tested.
2. Plan the test. Information concerning the industrial process
is used to determine such things as sampling location, number
and configuration of sampling points, chemical analyses required
and analysis methods to be employed, the design of the sampling
train, personnel required, and when the test is to be performed.
3. Supervise the conduct of the test. During the test the planner
is responsible to see that the plan is properly carried out and
a reliable and valid test is conducted. This may involve train-
ing and providing on-the-job guidance for junior level personnel
and evaluating" their performance. Another function of the planner
in this step is to assure that the industrial process is operating
as it typically would.
4. Analyze the results of| the test. Once all parameters have been
measured, either directly or via laboratory analysis, the results
must be evaluated. A report is then written appropriate to the
purpose of the test.
Occupational Category: Engineer
Task Deacription
The skill and knowledge analysis of this task is based on a con-
glomeration of all of the variations encountered in the air pollution
F-10
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control agencies. However, each of these variations is also contained
in one or more of the task descriptions presented in the publications
cited at the end of this analysis (References 1, 2, 4, 5, 6, 7, 10,
and 11). The remainder of the publications listed (References 3, 8,
and 9) contain useful information with regard to stack testing equip-
ment and selected testing techniques.
Skill Requirements
1. Ability to effectively communicate and cooperate with plant
personnel.
2. Ability to select the sampling location based on the following
op t imal condit ion s:
a. Distance of at least eight stack diameters downstream
and two diameters upstream of any obstructions, e.g.,
bends, fans, vents.
b. Vertical rather than horizontal duct.
c. Ample room for test personnel and apparatus.
d. Access to electrical power.
3. Ability to establish the number of required sampling points
according to the following criteria:
a. Proximity of the sampling location to any stack con-
ditions which might cause abnormal particulate stratifi-
cation.
b. Size and shape of the stack.
c. Gas velocity, volume, and turbulence.
4. Ability to design a sampling train which is appropriate for
a specific test with regard to the following criteria:
a. Stack temperature
b. Particle size
c. Moisture content of gas
F-ll
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d. Corrosive nature of the gas
e. Type of analysis to be performed
5. Ability to calculate a reasonable estimate of the total
amount of moisture expected to be condensed from the gas
sampled.
6. Ability to express technical theory and data in a concise,
intelligent manner.
7. Ability to evaluate the quantity and quality of work produced
by the staff and discriminate acceptable from unacceptable
performance. This skill assumes the ability to use criteria
of performance acceptability for all tasks supervised.
8. Ability to make work assignments and coordinate the efforts
of all personnel performing the stack test.
9. Ability to develop work procedures which provide detailed
step-by-step guidance in the performance of the stack test.
10. Ability to document all procedures, findings, ideas, and
decisions in writing which communicates clearly and completely
to the intended audience*
11. Ability to effectively communicate verbally with Equipment
Technicians concerning details of task performance.
12. Ability to cooperate with laboratory personnel in planning
tests so as to assure proper coordination of analysis and
sample collection activities.
13. Ability to choose a sampling time length and flow rate in
accordance with requirements for sample reliability and
representativeness and to avoid overloading the capacity
of the various reagents, filters, traps, ete., in the
sampling train.
F-12
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Knowledge Requirements
1. Knowledge of the procedure for obtaining information about
the process which produces the stack gases. Important infor-
mation might include:
a. Cyclic or steady state nature of the process
b. Feed composition and rate
c. Fuel rate
d. Gas volume
e. Operating temperatures and pressures
f. Toxic conditions
g. Schedule of operation
h. Control equipment
i. Expected type of emission
j. Stack dimensions
2. Knowledge of the effects on stack gas particulate concentration
resulting from each of the following stack characteristics:
a. Changes in direction
b. Horizontal duct
c. Fans
d. Vents
e. Change in the shape of the stack
3. Knowledge of the procedure for subdividing a circular or
rectangular stack cross section into a given number of equal
area zones.
4. Knowledge of the procedure for calculating the equivalent
diameter of a rectangular stack.
5. Knowledge of the factors which determine the selection of
either a standard or type S pitot tube for performing a
velocity traverse.
F-13
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6. Knowledge of the procedure for determing the correction
factor for a type S pitot tube.
7. Knowledge of the criteria for selecting a pressure-measuring
device for obtaining the velocity pressure of a particular
stack.
8. Knowledge of the proper technique for measuring the temperature
of stack gases, including knowledge of the criteria for select-
ing the most appropriate measuring device.
9. Knowledge of the procedure for determining the moisture content
of stack gases, using either a condenser or wet- and dry-bulb
thermometers.
10. Knowledge of the procedures for calculating the following stack
gas parameters:
a. Average molecular weight.
b. Specific gravity.
c. Average gas velocity.
d. Gas flow rate.
e. Gas flow rate, corrected to standard conditions of
temperature and pressure.
f. Average gas velocity, based on change measured at one
traverse point.
11. Knowledge of the procedure for calculating the expected sample
weight.
12. Knowledge of the capacity, applicability, and advantages of
different types of vacuum-producing devices, including a
variety of pumps, blowers, and aspirators.
13. Knowledge of the procedure for calculating the proper sampling
rate in order to achieve isokinetic sampling. The equation
for this calculation compensates for the change in temperature,
pressure, and moisture content of the gas as it passes from
the stack through the sampling train to the meter.
F-14
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14. Knowledge of the information required and presentation
format for reporting the results of a stack test.
15. Knowledge of the capabilities and work loads of the personnel
under his direction sufficient to permit the making of work
assignments.
16. Knowledge of the test procedures, apparatus, and calculations
for all variants of the stack test normally performed.
17. Knowledge of the theoretical background for the test procedures
and apparatus of concern.
18. Knowledge of each source which is pertinent to identifying
stack test methodology, its use and location.
19. Knowledge of the meaning of the following terms which are
used in the evaluation of a method:
a. Validity
b. Reliability
c. Accuracy
d. Precision
20. Knowledge*of the stack test procedure sufficient to:
a. Identify errors possible in each step of the procedure
and their effect on the final outcome of the analysis.
b. Identify critical steps in the procedure. A critical
step is one in which:
1) Errors are known to frequently occur
2) Little margin for error exists
3) Errors are likely to go undetected
c. Revise the procedue so as to reduce the possibility
of error.
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21. Knowledge of the chemical, electrical, and mechanical
principles of operation of the various stack test instruments
sufficient to:
a. Identify instrument malfunctions which could go
undetected and result in inaccurate read-out (to the
extent not already documented in existing service
manuals).
b. Develop procedures for the timely discovery of such
malfunctions.
c. Identify the effects of incprrect instrument operation
on instrument read-out.
22. Knowledge of the sampling procedures for determining the
chemical composition (percent C02» CO, 02, and N.) of stack
gas.
23, Knowledge of the procedure for calculating the expected sample
weight.
24. Knowledge of the procedure for selecting an appropriate filter-
ing media, given the expected sample weight, stack temperature,
and the moisture content of the gas.
25. Knowledge of the efficiency, use restrictions, advantages,
and disadvantages of each type of filtering media.
References
1. American Society for Testing and Materials. Standard method
for sampling stacks for particulate matter. Philadelphia:
Author, 1971. D2928-71.
2. American Society of Mechanical Engineers. Determining dust
concentration in a gas stream. New York: Author, 1957.
3. Committee on Industrial Ventilation. Industrial ventilation.
A manual of recommended practice. Lansing, Michigan:
American Conference of Governmental Industrial Hygienists,
1970 (llth Edition), pp. 9(1-8).
F-16
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4. Devorkin, H., Chass, R., Fudurich, A., & Kanter, C. R. Holmes
(Ed.) Air pollution source testing manual. Los Angeles: Air
Pollution Control District, Los Angeles County, November 1965.
5. Environmental Protection Agency. Standards of performance for
new stationary sources. Federal Register, Volume 36, Number
159, August 17, 1971.
6. Haaland, H. H. (Ed.) Methods for determination of velocity,
dust and mist content of gases. Bulletin WP-50. Seventh
Edition. Los Angeles: Western Precipitation Division/Joy
Manufacturing Company, 1968.
7. Jacobs, M. B. The chemical analysis of air pollutants. New
York: Interscience Publishers, Inc., I960. pp. 140-155.
8. Joy Manufacturing Company, Western Precipitation Division.
Gas velocity and dust determination equipment. Catalog
6V22. Los Angeles: Author.
9. Kimura, G. Emission control of flue-fed incinerators by use
of air pollution control devices. Chicago: Department of
Air Pollution Control, City of Chicago, November 1969.
pp. 87-90.
10. PEDCo-Environmental Specialists, Inc. Administrative and tech-
nical aspects of source sampling for particulates. Contract
No. CPA 70-124. Research Triangle Park, North Carolina:
Environmental Protection Agency, May 1971.
11• Weisburd,M. (Ed.) Air pollution control field operations
manual. A guide for inspection and enforcement. Washington,
D. C.: U. S. Department of Health, Education, and Welfare;
Public Health Service, Division of Air Pollution, 1962. PHSP
#937. pp. 167-76.
Special Staffing Guidance
The Engineer assigned ..to this task must possess all the skills and knowledge
of the Equipment Technician(s) actually performing the stack test (see Page
F-3).
F-17
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In addition, he must have the theoretical background necessary to design
test procedures and modify them to meet contingencies, administrative
skills necessary for coordinating technical personnel in the conduct
of the test, the ability to communicate clearly, verbally and in
writing, and sufficient formal education to permit him to act as a
credible representative of the agency when interacting with high level
plant personnel. These requirements suggest the need for at least a
Bachelor's Degree in an engineering field (e.g., industrial or chemical
engineering) with experience working on a stack test team.
F-18
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Determination of Odor Concentration
in the Atmosphere or in Stack Emissions
Task Overview
Several different methods have been proposed and studied for measuring
odor concentrations. These include both objective and subjective methods.
Among the objective methods, as they are described in Reference 4, are:
1. Adsorption on activated carbon
2. Oxidimitric method
3. Chemical methods
For the most part, these methods have not been well enough developed to
account for the complex interactions of many gas constituents in the
development of odors.
All of the subjective methods rely on the human olfactory perception of
successively diluted odor samples. The differences among the methods lie
in the various techniques used for diluting the sample. Some of the
subjective techniques are described in Reference 4 and elsewhere (as noted)
1. Syringe dilution method (see References 1 and 2)
2. Osmo method
3. Flow dilution method
4. Nader method
5. Scentometer method (see Reference 5)
At present, it appears that the syringe dilution method is the technique
predominantly employed by air pollution control agencies. Briefly, the
procedure is as follows:
1. An odor panel is selected, using an odor test in order to
eliminate people with poor olfactory capabilities.
2. A sample is taken from a stack or the atmosphere with a syringe.
3. The sample is diluted and transferred to dilution syringes.
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4. Panel members observe the diluted sample and report whether
or not they can detect an odor.
5. The odor concentration is calculated at threshold of odor percep-
tion of at least 50 percent of the odor panel.
Occupational Category; Equipment Technician
Task Description
The procedure for this method of determining odor concentration is
presented in usable form in Reference 2.
Skill Requirements
1. Ability to accurately prepare the solutions required for the
"triangle" test.
2. Ability to clean the syringes and needles such that they will be
odor-free.
3. Ability to use a soldering iron and silver solder to join the
two components of a transfer needle.
4. Ability to accurately transfer definite volumes of the odor
sample from one syringe to another.
5. Ability to determine the average velocity of discharge from a
stack, using a method similar to that described in Reference 3.
Knowledge Requirements
1. Knowledge of the definition of and the procedure for calculating
each of the following terms:
a. Odor unit
b. Odor concentration
c. Odor emission rate
2. Knowledge of the concept of absolute thresholds.
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3. Knowledge of the nature of possible interferences with valid
odor measurement. These include:
a. Extraneous odors and lingering taste effects
b. Poor physical condition of observer
c. Poor olfactory capabilities of observer
A. Knowledge of the procedure for preventing each interference,
including the procedure for conducting a "triangle" test for
panel selection.
5. Knowledge of the nomenclature, configuration, and principles of
operation of the apparatus required for performance of the task:
a. Luer type hypodermic syringe
b. Transfer needle
c. Syringe cap
6. Knowledge of the techniques for constructing a transfer needle,
7. Knowledge of the following procedures:
a. Procedure for acquiring the odor sample.
b. Procedure for preparing dilution samples.
c. Procedure for administering the diluted sample to the
observer.
References
1. Benforado, D. M., Rotella, W. J., and Horton, D. L. Development
of an odor panel for evaluation of odor control equipment.
Journal of the Air Pollution Control Association, Vol. 19,
No. 2, February 1969, pp. 101-105.
2. Fox, E. A., atfd Gex, V. E. Procedure for measuring con-
centration in air and gases. Journal of the Air_Pp_llution
Control Association. Vol. 7, No. 1, May 1957, pp. 60-61.
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3. Haaland, H. H. (Ed.) Methods for determination of velocity,
volume, dust and mist content of gases. Bulletin WP-50.
Seventh Edition. Los Angeles: Western Precipitation Division/
Joy Manufacturing Company, 1968.
4. Jacobs, M. B. The chemical analysis of air pollutants. New
York: Interscience Publishers, Inc., pp. 369-386.
5. Ward, F. R. Odor measurement with the scentometer. Norfolk,
Virginia: Odor Control Subcommittee, Industrial Standards
Subcommittee, Industrial Standards Committee, National Renderers
Association.
Special Staffing Guidance
1. Because this task has relatively few skill and knowledge requirements
it can be performed effectively by a junior level Equipment Technician.
2. This task and the operation of the smog chamber could be assigned
to the same Technician since both involve recruitment and testing
of human subjects, although there is otherwise little skill and
knowledge overlap between the two tasks.
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Performing a Used Car Inspection
Task Overview
There are a variety of inspection techniques designed to identify
automobiles producing excessive emissions. There are likewise variations
among procedures for performing inspections using a given technique,
e.g., the Idle test (see Page F-27).. Further, inspections can be per^
formed on all motor vehicles within an area or on a sample. The
procedure presented here is representative of the equipment inspection
technique in which idle speed, timing, and emission control equipment
are checked for compliance with manufacturers'specifications. In this
variant, only a sample of cars and used car lots are inspected. The
task is performed by two-person teams.
Occupational Category; Equipment Technician
Task Description
The inspection team arrives at the used car lot without forewarning
the manager at some time after sending him a letter explaining the
inspection program.
1. The inspection team leader identifies the inspection team
and elicits the voluntary compliance of the used car lot
managers.
2. The other team member (the inspector) counts the cars on the
lot and selects 10)percent at random for inspection. (Current
model year autos are usually not inspected) .
3. The team leader locates specification sheet for first car to
be inspected while the inspector attaches tachometer, dwell
meter and timing light to the car.
4. Car is started and permitted a short warmup (about three
minutes).
5. Idle speed, dwell, and timing are read by the inspector and
recorded by the leader who compares them to the specifications.
F-23
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6. The inspector tests the PVC valve using a PVC valve tester
and examines the condition of all emission control linkages,
valves, dashpots, solenoids, tubing, and wiring to be sure
that they are operational. His findings are recorded by
the leader and compared to specifications.
7. The engine is stopped, equipment disconnected, and the team
moves to the next car to be inspected.
8. The procedure is repeated until all cars selected have been
inspected.
9. The used car lot manager is immediately given or sent written
notification of the test results within a few days following
the inspection.
Skill Requirements
1. Ability to communicate effectively with, used car lot managers.
2. Ability to determine the make, model, and year of each auto
to be inspected.
3. Ability to read indicating devices, suck as a thermometer,
dwell meter, manometer, dry gas meter, tachometer, and flow-
meter, and to interpret meter readings against a calibration
plot as required.
4. Ability to read and interpret data from a table, psychometric
chart, or a nomograph.
5. Ability to detect leaks in hose, tubing, and piping connectors
carrying liquids, gaaes, or vacuum using simple leak detection
aids as appropriate.
6. Ability to disconnect and connect standard hose tubing and
piping connectors without injury to threads and achieving
leakproof connections. This includes the use of thread com-
pound and teflon tape as appropriate.
7. Ability to disconnect and connect standard electrical connectors.
This includes identifying leads to facilitate correct connection
and achieving tight connections without damage to the leads or
terminals.
F-24
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8. Ability to correctly interpret function diagrams, wiring
and tubing diagrams, simple electrical schematics, and trouble-
shooting charts.
9. Ability to detect pinched, ruptured or otherwise defective
tubing and incorrect tubing connection.
10. Ability to detect a worn, corroded, dirty, broken or otherwise
defective component part by visual, tactile, or auditory
examination and comparison with a properly functioning part.
Knowledge Requirements
1. Knowledge of the task procedure wi'th all steps in their proper
sequence.
2. Knowledge of the procedure making random selection of autos
to be inspected.
3. Knowledge of the procedures for attaching and operating the
tachometer, dwell meter, timing light, and PCV valve tester.
4. Knowledge of the type of emission control equipment to be
expected on each auto as a function of its make, model, and
year.
5. Knowledge of the procedure for determining the manufacturer's
recommended specification for idle speed, dwell, timing, and
the operation of all emission control equipment.
6. Knowledge of the function and location of each operating and
adjustment control on the test instruments.
Special Staffing Guidance
1. Because of the need for the leader of the Inspection team to interact
with car lot managers as a representative of the agency, the person
assigned to this position should have a good understanding of the
purposes and procedures of the inspection program and of general
F-25
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agency organization, functions, authority and policies. This require-
ment suggests the need for at least a senior level Equipment Technician
with several years of experience in the agency.
Because of the present lack of comprehensive highly proceduralized
documentation covering inspection of auto emissions control equip-
ment, the inspector must have an understanding of the basic principles
of operation of the various general types of emission control devices.
This suggests the need for an Equipment Technician with previous train-
ing in mechanical physics, chemistry and the theory of operation of the
internal combustion engine. Relatively extensive training either on-
the-job or formal will then be required to prepare this person for the
inspection task. For example, one formal course available through Sun
Electric Company requires one month of study.
F-26
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Performing the Idle and ACID Tests
Task Overview
The Idle and ACID tests are two techniques commonly used to measure hydro-
carbon 'and carbon monoxide emissions from motor vehicles. The Idle test,
being the simpler of the two, can be included within the discussion of the
ACID test.
The ACID test requires the use of a chassis dynamometer and involves opera-
ting the vehicle in four modes for about 15 seconds each:
1. 0-30 MPH acceleration
2. 30 MPH cruise
3. 30->0 deceleration
4. idle
Constant inertia and power settings specific to the vehicle being tested
are preset into the dynamometer. The entire exhaust is collected and CO
analysed by the nondispersive infrared technique (see Reference 3). Hydro-
carbons are measured by a flame ionization technique.
The Idle test involves simply testing the vehicle at idle using an analyzer
such as the infrared exhaust emission tester described in References 3 and
4. Assuming the vehicle is at operating temperature the test requires
about 35 seconds. No dynamometer is required.
Occupational Category; Equipment Technician
Task Related Material
Additional information relevant to the conduct of the ACID test can
be found In Reference 2; Information concerning the Idle test can be
found In Reference 1.
1The.task data reported here is incomplete; however, it is considered to be
highly indicative of the actual task characteristics and skill and
knowledge requirements.
F-27
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Skill Requirements
1. Ability to operate the chassis dynamometer.
2. Ability to operate the emissions test instrumentation.
3. Ability to maintain vehicle speed and vary speed smoothly and
at the rate required by the test procedure.
4. Ability to read indicating devices, such as a thermometer,
manometer, dry gas meter, and flowmeter, and to interpret meter
readings against a calibration plot as required.
5. Ability to coordinate adjustment screw or hand knob movements
with meter or chart recorder reading to quickly achieve and
maintain the desired reading.
Knowledge Requirements
1. Knowledge of the ACID test procedure.
2. Knowledge of the Idle test procedure.
3. Knowledge of the procedure for determining the dynamometer
power and inertia settings given the vehicle to be tested.
4. Knowledge of the function and location of each operating and
adjustment control on the test instrument(s).
5. Knowledge of the name and location of the various component
parts of the test instrument(s).
References
1. Andreatch, A. J., Elston, J. C., and Lahey, R. W. Motor vehicle
tune-up at idle. Trenton, New Jersey: New Jersey Department
of Environmental Protection.
2. Elston, J. C., Andreatch, A. J%, and Milask, L. J. Reduction of
exhaust pollutants through automotive inspection requirements—
the New Jersey REPAIR project, International Clean Air Conference
on Air Pollution, Washington, D. C., February 1971.
F-28
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3. State of New Jersey. Specification for exhaust gas analytical
system. Trenton, New Jersey: Author, February 15, 1972.
4. Sun Electric Corporation. Infra-red exhaust emission testing
handbook. Chicago, Illinois: Author.
5. Sun Electric Corporation. Product technical data and specifi-
cations—infra-red exhaust emission tester, Model EET-910.
Chicago, Illinois: Author.
Special Staffing Guidance
Performing the tests themselves is relatively, simple once the Equipment
Technician knows how to operate the chassis dynamometer and/or the emissions
test instrumentation. The Idle teat requires a minimum, of skill and knowledge,
assuming that instrumentation similar to the Sun EET-910 (Reference 4) is
employed, and can be effectively performed by an inexperienced junior level
Equipment Technician. The ACID test is more complex and probably should be
performed by the senior level Equipment Technician assigned to operate and
maintain the chassis dynamometer (see Page F-42).
It is important that the assignees for this task be able to effectively com-
municate with the public and able to clearly describe the nature of the tests
performed and the meaning of the results.
F-29
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Planning the Dynamometer Installation
Task Overview
Because of the large amount of physical space and site preparation involved
in the installation of either the chassis or engine dynamometers, planning
the installation deserves consideration as a task by itself. Basically,
planning entails choosing a site within the shop or laboratory facility
and designing the installation to facilitate hook-up of utilities and
the movement of autos or engines on and off the device and to provide
adequate working room for personnel.
Occupational Category: Engineer
Task Related Material
Material which provides information relevant to planning dynamometer
installations can be found in References 1 and 2.
Skill Requirements
1. Ability to plan the installation of the chassis dynamometer
including:
a. Determining the design of the installation through
identifying and coordinating the important design
variables including:
1) The space and construction characteristics and
limitations of the installation site.
2) The kinds of testing that will be performed using
the dynamometer.
3) Utilities requirements.
4) Human engineering requirements.
The task data reported here is incomplete; however, it is considered
to be highly indicative of the actual task characteristics and skill
and knowledge requirements.
F-30
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5) Safety considerations.
6) Maintenance and servicing requirements.
7) Equipment, spare parts, and materials storage
req ui rement s.
b. Reading and producing engineering drawings and blueprints.
c. Reading and understanding local plumbing and electrical
codes.
2. Abi-lity to plan the installation of the engine dynamometer
including:
a. Determining the design of the installation through
identifying and coordinating the various design variables
including:
1) The space and construction characteristics and
limitations of the installation site.
2) The kinds of testing that would be performed.
3) Utilities requirements (e.g., cooling water flow
and temperature, electricity).
4) Human engineering requirements.
5) Safety considerations
6) Maintenance and service requirements.
7) Equipment, spare parts, and materials storage
requirements.
b. Reading and producing engineering drawings and blueprints.
c. Reading and understanding local plumbing and electrical
codes.
Knowledge Requirements
1. Knowledge required to plan the installation of a chassis dyna-
mometer including: ,
a. The space requirements for the installation based on the
F-31
-------
amount and size of equipment (e.g., the vehicle cooler
and required test equipment) and the size of the vehicles
to be tested.
b. How to determine the best location for device to minimize
engine noise to other areas, out of normal shop traffic
flow.
c. Necessary service facilities characteristics:
1) Cooling and load water supply can be either domestic
or industrial, temperature not in excess of 80°F,
line pressure between 30 and 80 PSI, ideal pH is 9.
t
2) Cooling and load water disposal must have a minimum
of back pressure not to exceed one PSI.
3) Electrical supply of 115 volts A.C.
d. Local plumbing and electrical codes.
e. Floor thickness (top floor mount).
f. How to determine the stability of earth over which dyna-
mometer is to be installed (must be 2,000 Ibs./sq. ft.)
(flush mount).
g. Techniques for determining compressive strength of
concrete (flush mount).
h. How to determine the best type of installation, i.e.,
back-on drive-off, or drive-on back-off.
t
i. Procedure for dynamometer chassis installation.
j. Procedure for connecting utilities and instrumentation
to dynamometer.
k. How to determine the time peak demands are made on
water system.
1. Procedure for hooking up vehicle cooler system.
m. The testing procedure to be employed.
F-32
-------
n. Possible safety hazards (e.g., CO, explosive failure of
parts like flywheel and tires, vehicle rolling off
dynamometer).
o. Maintenance procedures.
2. Knowledge required to plan the installation of the engine
dynamometer including:
a. Knowledge of best location for device to minimize engine
noise to other areas, out of normal shop traffic flow,
and with facility provided for moving engine.
b. Knowledge of necessary service facilities characteristics:
1) Cooling and load water supply can be either domestic
or industrial, temperature not in excess of 80°F,
line pressure between 30 and 80 PSI, ideal pH is 9,
flow of 4.5 gallons per horsepower per hour.
2) Cooling and load water disposal must have a minimum
of back pressure not to exceed one PSI.
3) Water must not be excessively hard.
c. Knowledge of local water characteristics.
d. Knowledge of local plumbing and electrical codes.
e. Knowledge of procedures for foundation construction.
f. Knowledge of floor thickness (top floor mount).
g. Knowledge of the stability of earth over which dynamometer
is to be installed.
h. Knowledge of procedure for leveling dynamometer.
i. Knowledge of procedure for installing dynamometer cabinet.
j. Knowledge of which valve is "load-on" and which is "load-off"
k. Knowledge that there must be no contact between moving
(i.e., power absorption unit) and stationary components.
F-33
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1. Knowledge of procedure for plumbing and wiring hook-up.
m. Knowledge of whetfter series or parallel water flow is to
be used.
n. Testing procedures to be employed.
o. Ppssible safety hazards (e.g., CO rotating shafts,
hot manifolds, etc.).
p. Maintenance procedures.
References
t
1. Clayton Manufacturing Co. Instruction manual. Installation,
operation, and maintenance. Clayton chassis dynamometer,
Model DF-150 and DF-200. El Monte, California: Author.
2. Clayton Manufacturing Co. Instruction manual. Installation,
operation, and maintenance. Clayton engine dynamometer,
Model 17-300-CE. Model 17-500-CE, and Model 17-700-CE.
El Monte, California: Author.
Special Staffing Guidance
The person assigned this task must have a detailed knowledge of the
types of testing likely to be performed using the dynamometer (e.g.,
the sizes of engines or vehicle to be tested, the pollutants to be
measured, the need for accessory equipment like water or oil coolers)
and other uses of the shop or laboratory facility with which the operation
of the dynamometer might interfere. He must be able to coordinate
and satisfy various and conflicting design parameters and produce
detailed plans for use by plumber, electricians, other construction
personnel, and Equipment Technicians. These requirements suggest the.
need for a Bachelor's Degree in Mechanical or Civil Engineering, a
background in engineering drawing, and experience in structural design.
F-34
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Operation and Maintenance of the
. Engine Dynamometer
Task Overview
The engine dynamometer is used for measuring power output of a prime
mover in a controlled test situation prior to being placed in service.
During the test various "experiments" can be conducted to measure and
improve engine efficiency, thereby reducing exhaust emissions. The
power output shaft of the engine is coupled to the dynamometer shaft,
and operation of the engine spins the shaft 'and rotor which is enclosed
in a housing. A tachometer generator, belt driven from the shaft,
generates electrical current which is used to actuate the tachometer
which indicates engine* speed in RPMs. The power output of the engine
is absorbed by load fluid within the power absorption unit. The quan-
tity of fluid within the unit is increased or decreased by manipulation
of load and unload controls. Within the power absorption unit the rotor,
equipped with vanes, turns at close proximity to the stator in a housing
partly filled with "load water" and in so doing, develops a rotating
vortex of water. This vortex of water transmits kinetic energy to the
stator which is attached to the housing. This produces a rotative force
on the stator which is equal to the torque output of the engine. The
torque forces the entire power absorption unit to rotate on its axis and
operate the torque bridge through a system of linkage. As the torque
bridge is actuated by the rotating movement of the power absorption unit
mounted on cradle bearings, part of the current output of the tachometer
generator passes through the torque bridge and actuates the power meter,
which indicates engine power output in terms of horsepower. The load
water is cooled by being circulated across water-cooled tubes of a heat
exchanger by the pumping action of the rotor. Briefly, the steps re-
quired for operation and maintenance of the engine dynamometer include:
1. Installation of the engine dynamometer.
2. Operation of the engine dynamometer.
3. Periodic maintenance of the dynamometer.
F-35
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4. Troubleshooting of the device.
5. Power absorption unit repair.
6. Mechanical balance of the power absorption unit.
7. Hydraulic balance of power absorption unit.
8. Checking relief valve.
9. Servicing torque bridge.
10. Calibration of the dynamometer.
Occupational Category: Equipment Technician
Task Description
Reference 1 provides an example of the procedures for operation and
maintenance of ah engine dynamometer (the Clayton Engine Dynamometer,
Models 17-300-CE, 17-500-CE, and 17-700-CE). The following skill and
knowledge requirements are representative of this category of tasks.
Skill Requirements
1. Ability to install the engine dynamometer including:
a. Timing water flow to fill container of known capacity.
b. Running plumbing lines to carry water.
c. Drilling anchor holes without breaking through floor.
d. Correctly filling -anchor bolt holes with grout Csuch
as. "Emheco") after bolts are placed.
e. Using hoist and sling to position the dynamometer.
f. Aligning flexible tubing with frame by determining if
power absorption unit rotates when cooling water is
turned on.
f. Using electric drill to make screw holes in cabinet.
g. Adjusting tachometer generator drive belt.
F-36
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2. Ability to operate the engine dynamometer including:
a. Operating load control valves to achieve load desired,
coordinating operation with engine throttle adjustments.
b. Securing engine to be tested so that drive shafts are
in line.
c. Using appropriate flexible drive shaft coupler to
attach shafts.
d. Aligning drive shafts using steel rule and square.
3. Ability to service the engine dynamomerer including:
f
a. Cleaning cooling water strainer.
b. Checking and adjusting flywheel belt tension.
c. Oiling torque linkage pins, vee blocks, universal joints,
and cabinet door hinges and lock.
d. Lubricating main bearing with grease gun.
e. Checking and topping-off torque bridge fluid.
f. Blowing all water from dynamometer and vehicle cooler
systems using compressed air.
4. Ability to maintain the chassis and engine dynamometer including:
a. Removing roughness from shafts and other parts using
emery and crocus cloth without damage to the part.
b. Cleaning scale from heat exchanger by pumping acid
solution through it.
c. Pulling and pressing bearings and housings off and on
shafts.
d. Checking clearances.
e. Aligning couplings.
f. Cleaning parts.
g. Adjusting belt tensions.
h. Using portable hoist.
i. Riveting linings to brake shoes (chassis dynamometer).
F-37
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J. Assembling and disassembling components without damage
or loss of parts or injury to personnel.
k. Installing gaskets, "0" rings, and seals without damaging
them and using sealers as required.
1. Using a torque wrench.
m. Packing bearings.
5. Ability to troubleshoot the engine dynamometer including:
a. Determining if valve does not fully close.
b. Checking and adjusting tachometer generator belt.
c. Detecting excessive noise and vibration during dynamometer
operation.
6. Ability to calibrate the engine dynamometer including:
a. Using Syncrotac.
b. Installing calibration beam on power absorption unit.
c. Correctly positioning weight bracket on calibrating arm.
/
7. Ability to read indicating devices, such as a thermometer,
manometer, dry gas meter, and flowmeter, and to interpret
meter readings against a calibration plot as required.
8. Ability to coordinate adjustment screw or hand knob movements
with meter or chart recorder reading to quickly achieve and
maintain the desired reading.
9. Ability to level instrument or analyzer during installation
using a level, plumb, screw adjusters, and/or shims.
10. Ability to detect instrument damage caused by shipping, including
dents, breakage, components knocked out of position, loose
electrical and mechanical connections, and hairline cracks in
glass parts.
11. Ability to detect leaks in hose, tubing, and piping connectors
carrying liquids, gases, or vacuum using simple leak detection
aids as appropriate.
F-38
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12. Ability to disconnect and connect standard hose tubing and piping
connectors without injury to threads and achieving leakproof con-
nections. This includes the use of thread compound and teflon
tape as appropriate.
13. Ability to disconnect and connect standard electrical connectors.
This includes identifying leads to facilitate correct connection
and achieving tight connections without damage to the leads or
terminals.
14. Ability to correctly interpret function diagrams, wiring and
tubing,diagrams, simple electrical schematics and troubleshooting
charts.
\
15. Ability to interpret engineering drawings and piping diagrams.
16. Ability to detect a worn, corroded, dirty, broken or otherwise
defective component part by visual, tactile, or auditory exami-
nation and comparison with a properly functioning part.
Knowledge Requirements
1. Knowledge of the operation of a dynamometer including:
a. Speed and power meter "Hi" and "Lo" ranges.
b. Minimum-maximum pressure requirements.
c. Maximum water temperature limit (195°F).
d. Shaft rotation direction to be able to adjust tacho-
meter polarity appropriately.
e. Knowledge not to operate dynamometer completely unloaded
or over 150 HP with dynamometer flow control valves
closed.
f. Proc&dure for installing engine to be tested.
g. Appropriate shaft couplings, avoiding large and very
heavy type industrial couplings.
h. Procedures for hooking up and turning on engine cooling
water (also procedure for turning on dynamometer cooling
water).
F-39
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1. Procedures for starting and operating engine.
j. Procedure for proper engine run-in if engine is new or
rebuilt.
2. Knowledge required for servicing the engine dynamometer including:
a. Maintenance schedule.
b. Typical properties of torque bridge fluid to assure use
of correct fluid.
c. Procedure for performing periodic checks and lubrication.
d. Procedure for complete draining of water from system.
e. Procedure for cleaning water strainer.
f. Knowledge of procedure for cleaning heat exchanger.
g. Knowledge of procedure for replacing packing rings.
3. Knowledge required for maintaining the engine dynamometer
including:
a. Procedures for disassembly, inspecting, adjusting assembly
and testing of various components of the dynamometer.
b. The correct cleaning solutions, concentrations, and methods
to be used in cleaning the various components.
c. Safe handling procedures for hydrochloric acid and
paraformaldehyde (e.g., wearing rubber gloves, etc.).
d. Identification of all parts as they are removed from
power absorption unit to be sure they are replaced in
the same place.
e. The use of new seals and running rings when assembling
absorption unit.
f. Use of machinist's level.
4. Knowledge required to calibrate the engine dynamometer including:
a. Proper place to install Syncrotac.
F-40
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b. Procedure for speed meter calibration.
c. Procedure for power meter calibration.
5. Knowledge of the function and location of each operating and
adjustment control on the instrument.
6. Knowledge of the name and location of the various component
parts of the instrument.
7. Knowledge of the tools and materials required for maintaining
the instrument.
References .. ,,
1. Clayton Manufacturing Co. Instruction manual. Installation,
operation, and maintenance. Clayton engine dynamometer,
Model 17-300-CE. Model 17-500-CE, and Model 17-700-CE.
El Monte, California: Author.
Special Staffing Guidance
1. Because of the high skill and knowledge requirements for this task
it should be assigned to a senior level Equipment Technician.
2. The skills and knowledge required for this task are similar to those
required for operation and maintenance of the chassis dynamometer
so the same Technician should be assigned to both tasks (where the
agency has both types of dynamometer).
F-41
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Operation and Maintenance of the
Chassis Dynamometer
Task Overview
The chassis dynamometer is used to measure both the power and speed of
vehicles. As the vehicle is operated on the dynamometer, its drive wheels
are cradled between two rollers. A load is applied to the forward or
"drive" roller. The load may be increased, decreased, or held constant
at the option of the operator. These different loads are used to check
vehicle performance while accelerating, decelerating, and operating with
maximum load. The drive wheels of the vehicle rotate two ball bearing
mounted rollers. The drive roller is coupled to the power absorption
unit, and to an inertia flywheel. The rear or "idle" roller is used to
drive a tachometer generator. The power absorption unit is composed of
a shaft, rotor, stator, and heat exchanger, enclosed within a housing.
The drive roller turns the rotor at the same speed as the roller, and
in the same direction. The rotor, equipped with vanes, turns at close
proximity to the stator in a housing partly filled with "load water" and
in so doing, develops a rotating vortex of water which transmits kinetic
energy to the stator which is attached to the housing. This produces a
rotative force on the stator which is equal to the torque output of the
vehicle, and a torque arm delivers this force to the load cell which,
in turn, sends a signal to the power meter. Load water enters or leaves
the load water circuit as the load or unload valve is opened. As the
volume of water within the power absorption unit is increased, more power
is absorbed. Conversely, decreasing the volume of water decreases the
load. The load water is cooled by being circulated across water-cooled
tubes of a heat exchanger by the pumping action of the rotor. Briefly,
the steps required for operation and maintenance of the chassis dynamometer
include:
1. Installation of the dynamometer.
2. Placing the vehicle on the dynamometer.
3. Operation of the vehicle on the dynamometer.
F-42
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4. Periodic maintenance of the dynamometer.
5. Troubleshooting of the device.
6. Vehicle cooler pump and motor service.
7. Vehicle cooler heat exchanger cleaning.
8. Roller bearing replacement.
9. Solenoid load-unload valve cleaning.
10. Servicing remote load control.
11. Power absorption unit replacement.
12. Load cell service.
13. Tachometer generator service.
14. Inertia flywheel unit service.
15. Speed meter calibration.
16. Power meter calibration.
Occupational Category; Equipment Technician
Task Description
Reference 1 provides an example of the procedures for operation and
maintenance of a chassis dynamometer (the Clayton Chassis Dynamometer,
Models DF-50 and DF-200). The following skill and knowledge requirements
are representative of this category of tasks.
Skill Requirements
1. Ability to install the chassis dynamometer including:
a. Running plumbing lines to carry water.
b. Reading engineering drawings and blueprints.
c. Drilling anchor holes without breaking through floor
(top floor mount).
d. Correctly filling footing and anchor post hole with grout
(such as "Embeco") after chassis is installed (top floor
mount).
F-43
-------
e. Removing paint from trunnion.
f. Installing roll lock disc using light hammer and electric
drill.
g. Operating portable hoist.
h. Squaring anchor post with frame.
i. Drilling 1/2 inch holes in 4-inch by 4-inch timbers to
match holes in dynamometer frame. The timbers are laid
across each end of dynamometer and extend at least 12
inches beyond edge of foundation.
j. Centering dynamometer by aiigning center punch-out on
frame with center line of floor after dynamometer is raised
to level with floor using bolts passed through the frame
and timbers.
k. Blocking dynamometer to achieve stability by placing one-
inch boards cut to length between frame and foundation
at all four corners.
1. Determining when grout has reached a strength of 1,500 PSI.
m. Timing water flow to fill container of known capacity.
n. Adjusting tachometer generator belt tension.
o. Bleeding air from load cell.
p. Injecting transmission fluid into line connecting power
meter and load cell and bleeding air from system.
i
q. Priming cooler pump motor.
r. Securing,ramps to floor with bolts (top floor mount).
2. Ability to operate the chassis dynamometer including:
a. Aligning vehicle on dynamometer. This is aided by
painting a stripe on floor along driver's side.
b. Judging power absorption unit temperature by feeling
with palm of hand.
F-44
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c. Controling load with load control pushbuttons.
d. Coordinating vehicle throttle and load control adjustments
to maintain preselected speed and opening throttle fully.
e. Blowing all water from dynamometer and vehicle cooler
systems using compressed air.
3. Ability to service the chassis dynamometer including:
a. Replacing magnesium plug-in power absorption unit.
b. Lubricating flywheel bearings and pins and guide channels
actuated by flywheel engagement lever.
c. Cleaning cooling water strainer.
d. Checking and adjusting tachometer generator belt tension.
e. Checking and adjusting flywheel belt tension.
f. Checking and adjusting flywheel brake adjustment.
g. Lubricating flexible shaft couplings by installing
lubrication fitting and injecting lubricant.
h. Removing grease, oil, and water from rollers and approach
to dynamometer.
4. Ability to troubleshoot the chassis dynamometer including:
a. Locating bend or deflect in hoses.
b. Checking drive belt tension.
c. Checking electrical power supply.
d. Checking if pump is primed.
e. Detecting excessive noise and vibration during dynamometer
operation.
5. Ability to maintain the chassis and engine dynamometer including:
a. Removing roughness from shafts and other parts using
emery and crocus cloth without damage to the part.
b. Cleaning scale from heat exchanger by pumping acid
solution through it.
F-45
-------
c. Pulling and pressing bearings and housings off and on
shafts.
d. Checking clearances.
e. Aligning couplings.
f. Cleaning parts.
g. Adjusting belt tensions.
h. Using portable hoist.
i. Riveting linings to brake shoes (chassis dynamometer).
j. Assembling and disassembling components without damage
*
or loss of parts or injury to personnel.
k. Installing gaskets, "0" rings, and seals without damaging
them and using sealers as required.
1. Using a torque wrench.
m. Packing bearings.
6. Ability to calibrate the chassis dynamometer including:
a. Installing calibration arm on torque arm.
b. Correctly positioning weight stand on calibrating arm.
c. Moving load cell in or out to achieve proper readings.
d. Resetting tare on power meter by removing face and turning
micrometer screw on meter hand.
7. Ability to read indicating devices, such as a thermometer, manometer,
dry gas meter, and flowmeter, and to interpret meter readings
against a calibration plot as required.
8. Ability to read and interpret data from a table, psychometric
chart, or a nomograph.
9. Ability to level instrument or analyzer during installation
using a level, plumb, screw adjusters, and/or shims.
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10. Ability to detect leaks in hose, tubing, and piping connectors
carrying liquids, gases, or vacuum using simple leak detection
aids as appropriate.
11. Ability to disconnect and connect standard hose tubing and piping
connectors without injury to threads and achieving leakproof con-
nections. This includes the use of thread compound and teflon
tape as appropriate.
12. Ability to disconnect and connect standard electrical connectors.
This includes identifying leads to facilitate correct connection
and achieving tight connections without damage to the leads or
terminals.
13. Ability to correctly interpret function diagrams, wiring and tubing
diagrams, simple electrical schematics and troubleshooting charts.
14. Ability to interpret engineering drawings and piping diagrams.
15. Ability to detect a worn, corroded, dirty, broken or otherwise
defective component part by visual, tactile, or auditory
examination and comparison with a properly functioning part.
Knowledge Requirements
1. Knowledge of the procedure for installing a dynamometer.
2. Knowledge of the operation of the dynamometer including:
a. Procedure for locking dynamometer rollers.
b. Maximum allowable temperature of power absorption
unit (150°F).
c. Knowledge that flywheel must not be engaged while rollers
are turning, or disengaged while operating in excess of
20 MPH.
d. Safe top speed when flywheel is operating (65 MPH).
e. Procedure for attaching vehicle cooler to vehicle
(water cooled).
f. Procedure for completely draining dynamometer and cooler
of water.
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3. Knowledge required for servicing the dynamometer including:
a. Preventive maintenance schedule.
b. Procedure for performing periodic checks and lubrications.
4. Knowledge required for troubleshooting the dynamometer including:
a. Symptom patterns.
b. Techniques for using symptom/cause table.
5. Knowledge required to maintain the dynamometer including:
a. Procedures for disassembly, inspection, and assembly
of various components of the dynamometer.
*
b. Proper cleaning solution concentration to be used in
various stages of cleaning.
c. Safe handling procedures for hydrochloric acid and
paraformaldehyde (e.g., wearing rubber gloves, etc.).
d. Procedure for checking alignment of shaft coupling hubs.
e. Procedure for attaching and operating a bearing puller.
f. Technique for identifying hoses to assure connection
to correct fittings upon replacement.
6. Knowledge required to calibrate the dynamometer including:
a. Knowledge that there is no tire slippage, tachometer
belt slippage, loose or broken wires or tubing before
beginning calibration.
b. Procedure for use of the Syncrotac.
c. Characteristics of smooth-running vehicle.
d. Procedure for calibration of speed meter.
e. Procedure for calibration of power meter.
7. Knowledge of the function and location of each operating and
adjustment control on the Instrument.
8. Knowledge of the name and location of the various component
parts of the instrument.
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9. Knowledge of the tools and aaterials required for maintaining
the in s t rumen t.
References
1. Clayton Manufacturing Co. Instruction manual. Installation,
operation, and maintenance. Clayton chassis dynamometer,
Model DF-150 and DF-20Q. El Monte, California: Author.
Special Staffing Guidance
1. Because of the high skill and knowledge requirements for this task
it should be assigned to a senior level Equipment Technician.
2. The skills and knowledge required for this task are similar to those
required for operation and maintenance of the engine dynamometer so
the same Technician should be assigned to both tasks (where the
agency has both types of dynamometer).
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