EPA-AA-IKS-30-5-B
TECHNICAL REPORT
SEPTEMBER, 1980
RECOMMENDED SPECIFICATIONS
FOR
EMISSION INSPECTION ANALYZERS
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EPA-AA-IMS-80-5-B
Technical Report
September, 1980
Recommended Specifications
for
Emission Inspection Analyzers
by
William B. Clemmens
NOTICE
Technical Reports do not necessarily represent final EPA decisions or posi-
tions. They are intended to present technical analyses of issues using data
which are currently available. The purpose in the release of such reports
is to facilitate the exchange of technical information and to inform the
public of technical developments which may form the basis for a final EPA
decision, position, or regulatory action.
Inspection and Maintenance Staff
Emission Control Technology Division
Office of Mobile Source Air Pollution Control
U.S. Environmental Protection Agency
Note: This report (-80-5-B) is the second section of two sections. The
first section -80-5-A contains Background, Technical Discussions,
and Policy Information on Inspection Analyzers. Both sections (-A
and -B) are available separately.
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Table of Contents
Acknowledgments
Executive Summary
Technical Report
£-__ _
Chapters I through V can be found
in
EPA-AA-IMS-80-5-A
Analyzer Specifications 10
VI. How to Use The Specifications 11
A. Overview 11
B. Analyzer Technology 12
C. Change Notices 12
D. Definitions and Abbreviations 13
VII. Recommended State Minimum Specifications 16
A. Gases 19
B. Gas Cylinders 21
C. Durability Criteria 22
D. Design Requirements 23
E. Analyzer Performance 31
F. Sample System Performance 34
G. Operating Environment 36
H. Fail-Safe Features 37
I. System Correlation to Laboratory Analyzers 38
J. Manuals 39
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Table of Contents (continued)
VIII. Additional System Specifications
Recommended For Decentralized Inspection Programs
A. Automatic Zero/Span Check 41
B. Automatic Leak-Check 43
C. Automatic Hang-Up Check 44
D. Automatic Read System 45
E. Dual Tailpipes 45
F. Automatic Test Sequence 46
G. Printer 48
H. Vehicle Diagnosis 48
I. Anti-Tampering 48
J. System Diagnosis Testing 49
IX. Optional Features For The Inspection Analyzer 50
A. Automatic Data Collection 50
B. [Deleted] 52
C. Anti-Dilution 53
D. Loaded Mode Kit 54
E. Engine Tachometer 55
X. Future Improvements For The Inspection Analyzer 56
A. Introduction 56
B. Improvements in Water Removal 56
C. Improvements in HC Measurement 57
XI. Evaluation Procedures 59
A. Traceability of Analytical Gases 60
B. Gas Cylinder Specifications 61
C. Durability Test Procedures 62
1. Vibration and Shock 62
2. Sample Line Crush 64
3. Sample Handling Temperature Effect 67
4. Filter Check and Hang-up
D. Design Requirement Inspection and Test Procedures 70
1. Useful Life 70
2. Name Plate 70
3. Sample System 70
4. Sample Pump 70
5. Sample Probe 70
6. Sample Line 70
7. Analyzer Spanning System 71
8. Analyzer Ranges 71
9. System Grounding 71
10. System Vents - 71
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Table of Contents (continued)
E. Analyzer Performance Test Procedures 72
1. Calibration Curve 72
2. Resolution 74
3. Compensation 75
a) Altitude 75
b) Pressure and Temperature 78
c) Non—Compensated Systems 81
4. Zero and Span Drift 82
5. Span Drift (see E.4.) 85
6. Noise (see E.8.) 85
7- Sample Cell Temperature 86
8. Gaseous Interference and Noise 88
9. Electrical Interference 91
10. Propane to Hexane Conversion Factor 95
F. Sample System Test Procedure 98
1. Sample Cell Pressure Variation, Low Flow and 98
Response Time
2. (See F.I.) 102
3. (See F.I.) 102
4. (See F.I.) 102
5. System Leakage 103
6. (See C.4) 104
G. Operating Environment Test Procedure 105
H. Fail-Safe Systems 107
1. Warm-up Lock-out 107
2. Low Flow 109
I. System Correlation Test Procedures 110
1. NDIR Correlation 110
2. FID Correlation 114
J. Micro Processor Systems 117
1. Automatic Zero/Span 117
2. Automatic Leak Check 117
3. Automatic Hang-up 117
4. Automatic Read 117
5. Dual Tailpipes 118
6. Automatic Test Sequence 118
7. Printer 118
8. Vehicle Diagnosis 118
9. Anti-Tamper ing 118
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Acknowledgments
The contributions and stimulating discussions with Merrill Korth and Gordon
Kennedy of EPA during the formative stages of the technical specifications
are greatly appreciated. The inputs and numerous reviews provided by the
Equipment and Tool Institute Performance Test Group have greatly aided the
preparation of this specification.
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EXECUTIVE
SUtlARY
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EXECUTIVE SUMMARY
EPA Recommended Instrument Specifications
The instrument used to measure motor vehicle exhaust concentrations of
hydrocarbon (HC) and carbon monoxide (CO) is typically called a garage
analyzer. This commonly used title has considerable significance to the I/M
program Administrator choosing a minimum specification for exhaust ana-
lyzers. The word "garage" indicates the location where the instrument is
used. "Garage" also refers to its intended use; to assist in the diagnosis
and repair of engines and emission control systems. As those familiar with
diagnoses and repair using an exhaust analyzer know, the relative level of
pollutants, and the change in emission levels in response to an adjustment
or repair, are most important in servicing a vehicle.
The I/M program places a new burden on these instruments: inspection. An
inspection of the vehicle's exhaust requires an accurate measurement of the
pollutant concentration, not just a relative level. Whether a vehicle
requires repair depends on this measurement, and accuracy becomes an impor-
tant consideration. The instrument must provide a repeatable measurement in
order to assure equitable inspection for each motorist. The failure to
achieve repeatability inevitably results in challenges to the program's
credibility.
The current garage type repair analyzer has been used as an inspection
analyzer in currently operating I/M programs. In centralized I/M programs,
its design capability has been greatly complemented by computer control and
very frequent calibration and maintenance. It is continually under the
watchful eye of an experienced instrument technician, and' its working envi-
ronment is often carefully controlled.
In decentralized I/M programs, the repair analyzer has also been used as an
inspection tool, but with little consideration for its original intended
use. The one concession to this situation has been periodic state checks of
the instrument's calibration.
In the garage environment, the inability of the repair analyzer to provide
accurate and repeatable measurements is well established. A recent NHTSA
study indicated 32 percent of field use exhaust analyzers were reading more
than 15 percent too high or too low. The study had attempted to use the
industry standard of accuracy of ±3%, but found virtually no analyzer could
meet this requirement. At ±5%, 93 percent of analyzers were inaccurate or
not repeatable.
In addition, the performance specifications of repair analyzers often are
inappropriate for inspection purposes. As an example, most instruments are
designed to operate at 0 to 85% relative humidity. As an inspection ana-
lyzer, this could preclude use on high humidity days. In many areas of the
country, this specification effectively limits the use of the instrument for
a large portion of the year. This is of course an impractical result, yet
the instrument manufacturers have done nothing to rectify this problem.
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Several attempts to improve the inspection analyzer by establishing minimum
specifications have been made. In 1974, the California Bureau of Automotive
Repair (BAR) published its first minimum instrument specification applicable
to garages participating in its Blue Shield inspection program. In 1980 BAR
upgraded this specification. This year, the Equipment and Tool Institute
(ETI), an industry organization, published its own specification, and has
widely disseminated it to states preparing I/M programs. EPA has reviewed
each of these specifications and finds them lacking in two areas: 1) fail-
ure to consider how the operator affects the measured results, and 2) speci-
ficity of accreditation procedures.
Based on an error propagation model, EPA determined that the most important
factor involving accurate exhaust measurements was proper operating proce-
dures. EPA determined that incorrect gas spanning (calibration) could
affect emission measurements by up to 40%, improper purging by up to 100%,
leaks by 100%, and improper meter reading by 20%. Under the best of condi-
tions, current equipment has a measurement accuracy of 25% to 35%.
The assessment indicated that minor, but important design changes could
improve optimum accuracy to the 10 to 20 percent range. The improvements
involve the detector, sample cell, and signal conditioning, and can be
incorporated into existing designs with relative ease. EPA recommends that
all states implementing centralized I/M programs adopt the EPA recommended
specification for a manually operated analyzer. The specification, includ-
ing detailed acceptance procedures, can be found in EPA-AA-IMS-80-5-B,
"Recommended Specification for Emission Inspection Analyzers".
These improvements do not address the proper operation of the instrument.
In centralized programs, this is dealt with through use of inspection per-
sonnel thoroughly familiar with the instrument, through ' recordkeeping and
frequent calibration and maintenance, and often through real time computer
control of the instrument.
In decentralized programs, the station operator or mechanic cannot be ex-
pected to become an instrument technician, the sophistication of the in-
strument precludes this. The cost pressures of completing the inspection as
rapidly as possible encourage failure to provide proper calibration and leak
checks. In fact, the calibration and maintenance requirements of these
analyzers exceed those of any other garage instrument. Incompetence and
fraudulent practices are also considerations in a decentralized program
because of minimal inherent checks on the quality of the operation.
The advent of the $15 pocket calculator and the $800 home computer provides
a practical solution to most of the problems of proper operation of the
inspection analyzer in a decentralized I/M program. With the addition to
each instrument of a small microcomputer, the inspection instrument can take
on most of the calibration and recordkeeping burden. This computer operated
analyzer will restrict operation until the unit is fully warm, will provide
for automated gas span and leak checks, can accept vehicle ID and other
information, will automatically make the pass/fail decision, will provide a
hard copy output (which can include diagnostic information), and can store
pertinent data on magnetic tape for future state analysis.
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Such analyzers are not a wishful dream. One repair analyzer produced by
Hamilton Test Systems incorporates some of these features and is commer-
cially available. The New Jersey inspection program is currently evaluating
a computerized unit produced by Sun Electric. New York State has recently
contracted for over 4000 computerized analyzers for its decentralized I/M
program. Given these recent developments, EPA's assessment of 9 to 18
months before quantities of units meeting its specification are available
may be overly pessimistic.
EPA strongly recommends that each state implementing a decentralized I/M
program adopt the EPA specification for a computer operated analyzer. The
complete specification and detailed acceptance procedures can be found in
EPA-AA-IMS-80-5-B ("Recommended Specifications for Emission Inspection
Analyzers"). A drawing of an existing prototype follows this executive
summary. EPA Report EPA-AA-IMS-80-5-A ("Analysis of the Emission Inspection
Analyzer") provides considerable information on the need and benefits of
adopting the computer operated analyzer.
Computerized features will increase the cost of the inspection analyzer.
The attached report (EPA-AA-IMS-80-5-A) estimates that the full cost of the
analyzer will be recovered for 2 to 3 dollars per test. In addition, the
cost to the garage owner can be reduced through investment credits and
depreciation. These considerations are fully discussed in the report. The
estimated cost (1980 dollars) of the various types of analyzers is shown
below.
EPA computerized $6195 to 7395
EPA manual operation $4490 to 5690
BAR 80 certified $3750 to 4950
Current Repair Analyzer (ETI) $3000 to 3750'
The computer operator analyzer will allow a reduced frequency of state
audits of licensed decentralized inspection stations. Because of the in-
strument's self-calibration feature, quarterly audits will provide quality
assurance equivalent to the otherwise required monthly audits. This pro-
vision will reduce program administration costs, and should be an incentive
for State adoption of the EPA recommended analyzer.
The impact on implementation schedules of the lead time to procure instru-
ments meeting this specification is discussed in a separate memorandum to
EPA's Regional Administrators from the Assistant Administrator for Air,
Noise and Radiation.
Finally, the I/M staff at EPA's Ann Arbor facility is available to provide
additional assistance and information as necessary. You may contact Tom
Cackette, Donald White, or Bill Clemmens at (313)668-4367.
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10
ANALYZER
SPECIFICATIONS
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VI. How to Use the Specifications
A. Overview
The recommended specifications are presented in the next four chapters (VII
through X). Chapter VII presents the basic specifications for inspection
analyzers. Those specifications are designed to be consistant with manual
operation of the analyzer. Chapter VIII describes the addition features
that would be needed to create a computer operated analyzer from the basic
Chapter VII analyzer. The performance aspects of the Chapter VII specifica-
tions are applicable to both the manual and computer operated analyzers.
Optional equipment such as automatic data aquisition for either type of
inspection analyzer are detailed in Chapter IX. Chapter X provides some
suggestions for future improvements that should be made to the basic ana-
lyzer.
An important aspect of any set of specifications is the Interpretation of
those specifications. The specific test procedures used to evaluate the
performance of a piece of equipment essentially determines one interpreta-
tion of the requirements. Different test procedures can provide different
results. The order that the tests are performed can also affect the re-
sults.
Chapter XI provides the EPA recommended evaluation test procedures. These
procedures are intended to provide a consistant technique to verify analyzer
performance. The suggested testing order is:
1. Follow manufacturer's initial start-up and pre-test procedure as
listed in the manufacturer's manual(s).
2. Durability Tests
1st - Vibration and Shock Test
2nd - Sample Line Crush Test
3rd - Temperature Effect
4th - Filter Check
3. Inspect Design Requirements
4. Analyzer Performance
5. Sample System Performance
6. Operating Environment Test
7. Fail-Safe Features
8. Correlation Tests
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If an analyzer passes the evaluation tests, the user can be fairly confident
of the in-use emission test results from that particular- analyzer. In order
to apply the evaluation results to the general production line units, more
analyzers must be tested. A recommended quality audit testing plan is
provided in the introduction to Chapter VII.
B. Analyzer Technology
These specifications were determined based on current I/M practice of using
non-dispersive infrared (NDIR) analyzers for HC and CO measurements. Noth-
ing in these specifications should be construed as prohibiting other ana-
lysis techniques. Potential improvements in technology should be considered
on a case by case basis. To that extent, many of the concepts expressed by
these specifications can be applied.
C. Change Notices
At the present EPA has no formal mechanism for disseminating improvements or
interpretations on subjects discussed in technical reports. The exception
is if the report is published as part of a formal notice or regulation in
the Federal Register. In that case, dissemination of changes occur through
technical amendments, also published in the Federal Register.
In the case of this report, experience gained through wide spread use will
most likely lead to improvements in the test procedures. Further, new
technology may obsolete certain parameters while at the same time require
evaluation of new or additional parameters. The point to stress to State
Program Managers is that any specification on I/M analyzers should allow
some flexibility to deal with the issues just mentioned. However, the
flexibility for change must be predicated on the concept o'f "meet or exceed"
the criteria listed in the recommendations. In practically all cases veri-
fication of the meet or exceed criteria would be required, and would include
comparison testing and statistical evaluation of the test data.
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D. Definitions and Abbreviations
The following definitions are for reference. For many definitions, the
specific test procedures used for vertification of the specifications pro-
vide the final interpretation.
1. Accreditation: Certification that an analysis system has been
tested by the required procedures, and it has been verified that the
analysis system complies with those specifications. Further, accredi-
tation implies that the analyzer manufacturer follows proper procedures
to insure that subsequent production systems are also in compliance.
2. Accuracy; The combination of bias and precision errors, techni-
cally defined as Uncertainty, that quantify the difference between the
analyzer reading and the true value (see equivalency).
3. Analytical Gases; Gases of known concentration used in the ana-
lytical process as a reference. The four basic categories are:
Gas Use
a) Zero Gas Laboratory, Manufacturer, and
State Auditor
b) Calibration Gas Laboratory and Manufacturer
c) Audit Gas State Auditor
d) Span Gas Field Emission Inspector
4. Analysis System; A system that incorporates an analyzer(s) and
sampling components for the purpose of exhaust gas analysis.
5. Analyzer; A device that has the capability to identify unknown
concentrations of particular constituents in automobile or truck ex-
haust gases by comparison to analytical gases. Commonly used inter-
changeably with "instrument".
6. Calibration; The act of defining or checking the full calibration
curve of the analyzer. Generally considered a laboratory procedure,
calibration requires 6 to 12 calibration gases per analyzer range or
scale.
7. Calibration Curve; A curve (usually a polynomial) that describes
the relationship between meter movement (i.e. chart deflection or
voltage) and concentration level. For field instruments the cali-
bration curve is usually fixed at the factory.
8. Calibration Gases; Analytical gases that are used to determine the
accuracy of an analyzer calibration curve.
9. CO: carbon monoxide
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10. CO : carbon dioxide
11. Detector: The portion of the analyzer that detects the constitu-
ent of interest, and provides the original signal proportional to the
concentration of the constituent.
12. Drift: The average amount of change with time of analyzer read-
ing. Two components of drift are:
a) Zero drift - average change in zero reading
b) Span drift - average change in the difference between zero and
span readings
13. Dry-Basis Concentration; The resultant concentration after the
water has been removed from the sample either physically or by elec-
tronic simulation techniques.
14. Equivalency; A statistical comparison of a candidate analysis
system performance versus the reference analysis system performance on
exhaust gas in order to determine the acceptability of the candidate
system.
15. FID; Flame ionization detector. Most common laboratory analyzer
used for determination of hydrocarbon (HC) concentrations in exhaust
samples.
16. fs; Full scale of the analyzer.
17. Hang-up; Hang-up refers to the process of hydrocarbon molecules
being absorbed, adsorbed, condensed, or by any other method removed
from the sample flow prior to reaching the analyzer detector. It also
refers to any subsequent desorbtion of the molecules into the sample
flow when they are assumed to be absent.
18. HC; hydrocarbons
19. Instrument; see analyzer
20. Interference (electronic); Analyzer read-out errors caused by
instrument response to electromagnetic sources and power supply varia-
tions. Common forms of electromagnetic sources are:
a) Radio Frequency Interference (RFI)
b) Very High Frequency Interference (VHF)
21. Interference (gases); Analyzer read-out errors caused by instru-
ment response to non-interest gases typically occuring in vehicle
exhaust.
22. L.S.; Low scale or range of the analyzer.
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23. NDIR; Non-dispersive Infrared Analyzers
24. Optical Bench; The portion of the analyzer that consists of the
main sample processing and detecting assembly. Generally included are
the detector, optical filters, sample tubes, infra red source, and
chopper systems.
25. Precision; Statistical quantification of random measurement
errors.
26. ppm; parts per million by volume
27. ppm C; ppm by Carbon atom
28. ppm C3 or ppmp: ppm propane (C_ H )
-i i_ j y
29. ppm C6 or ppmh; ppm n-hexane
30. Propane to Hexane Conversion Factor; A factor that accounts for
the difference in analyzer response (relative response) between propane
and n-hexane. Sometimes referred to as a "C" factor, or a propane
equivalence factor (P.E.F.).
31. Response; Analyzer indication to a gas.
32. Response Time; The reaction time between a change in concentra-
tion at the inlet to the sample system and the time the analyzer indi-
cates a given percentage of that change.
33. Sample System: The portion of the analysis system that is respon-
sible for delivering an unaltered sample to the analyzer.
34. Span or Spanning; The act of adjusting the analyzer's calibration
curve into the correct reference frame. Gas spanning uses a span gas
for a reference during the adjustment process. Electrical spanning
attempts to duplicate the span gas voltage level to be used as a surro-
gate reference during the adjustment process.
35. Span Gases; Analytical gases that are used to adjust or return
the analyzer response characteristics to those determined by the cali-
bration gases.
36. Zero Gas; An analytical gas that is used to set the analyzer
response at zero.
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VII. Recommended State Minimum Specifications
The recommended State minimum specifications are intended to be applied to
both decentralized and centralized analysis systems. The particular speci-
fications in this chapter are written with the assumption of manual opera-
tion of the analyzer. In order to perform the proper interactions, the
operator must have a set of written instructions that are equivalent in
function to the sequence of events performed by the computer analyzer speci-
fied for decentralized systems described in Chapter VIII. It is recommended
that the analyzer manufacturer provide these written instructions, and it is
necessary that the centralized programs implement these procedures in order
to properly utilize the analysis systems.
These specifications are intended to apply to a manufacturer's entire pro-
duction of inspection analyzers. In order to verify that the production
line does meet the specifications, the testing plan in Table VII-1 is recom-
mended. Reciprocity of qualification and QA/QC testing results should be
accepted.
In preparing the analyzer for qualification or QA/QC testing, many evalu-
ation test procedures require monitoring of internal analyzer signals or
parameters. In order to decrease evaluation set-up time, the analyzer
manufacturer may instrument the candidate analyzer(s) to provide convenient
access to the necessary signals. No other modifications are allowed, and in
some cases the manufacturer may be required to prove his instrumentation
process does not affect the analyzer's performance.
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Table VII-1
Recommended Qualification Program
I. Pre-Production
1. The manufacturer may receive a preliminary accreditation, valid for six
months, by providing a publically released report which demonstrates that at
least one pre-production unit has passed all evaluation tests.
II. Initial Production QA/QC
1. The manufacturer shall also select, in a random manner, three of the
first 20 production units, and all three shall receive all evaluation tests.
2. If two of the three units pass all evaluation tests, the instrument shall
receive full accreditation valid for a period of three years from the date
the first unit was produced.
3. If two or more units fail the evaluation tests, corrections to the design
and/or production must be made, and three additional units selected from a
new or current production run. Two of these three must pass all evaluation
tests.
4. All units covered by a preliminary accreditation and produced prior to
the production run in which full accreditation is received shall be required
to incorporate the necessary design and/or production fixes.
III. Subsequent Production QA/QC
The accreditation may be renewed for a three year period at any time by
passing all evaluation tests on two of three units selected randomly from a
production run of 20.
IV. QA/QC Testing Criteria
1. Two (2) of the three(3) production units must pass with no design or
random failures.
2. A design failure is defined as a failure to meet the evaluation procedure
criteria.
3. A random failure is defined as the failure of a standard part in the
system (i.e. pump, electrical resistor, etc.) where improved procurement
specification, assembly technique, or pre-assembly QC on that part would
reduce failures in the field.
4. An infant mortality is defined as the total failure of a part (usually a
computer chip or related components) within a short period of time after the
unit first receives any electrical power. Infant mortality failures must
have sufficient documentation (i.e. published report available to regulatory
bodies) to justify why the failure can be attributed as infant mortality and
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not minor design failure. Infant mortality failure is not classified as an
analyzer failure if the failure would be obvious in the field. After re-
pairs, those tests that might be affected by the repairs must be rerun.
5. Random failures must have sufficient documentation (i.e. published report
available to regulatory bodies) to justify why the failure can be attributed
as a random failure and not minor design failure. Random failures may be
repaired on pre-production units only. A condition to allow the repair of
the pre-production analyzer is the development of a plan (where necessary)
to prevent the specific type of failure in production units. After repairs,
those tests that might be affected by the repairs should be rerun.
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Spec: A.I.-2.
A. Gases
1. Accuracy
a) Calibration and Audit gases: + 2% of True Value, or
+ 1% of NBS Standard Reference
~ Material (SRM)
b) Span gases: + 3% of True Value, or
+ 2% of NBS Standard Reference Material
c) Zero gases: less than 10 ppm C hydrocarbon
less than 50 ppm CO
less than 1000 ppm CO
2. Composition
a) Span gases should be CO and HC (propane) with N as diluent
b) Calibration and Audit gases should be:
i) HC (propane) with N as diluent, and
ii) CO with N2 as diluent
c) C0? with N? or air zero gas as diluent (span or calibration)
d) Zero gas may be
i) bottled air,
ii) chemically purified room air such as with an activated
charcoal trap on the analysis system, or
iii) catalytically purified room air
e) Hexane to propane conversion factor checking gases shall
consist of n-hexane in nitrogen, gravimetrically blended to the
accuracy of SRM's. The gravimetric analysis is only valid for 1
year from the date of analysis unless historical data and corre-
lation checks can verify stability of the gas concentration. The
gravimetric analysis is void if the gas cylinder temperature drops
below 20°C (68°F) for any reason including shipping and storage.
An alternative to the 20°C minimum temperature is to condition the
gas cylinders at least one week after receipt of the cylinders in
a temperature environment between 27°C (80.6°F) and 48°C (118°F).
During the one week conditioning, the cylinders shall be stored on
their sides, and rolled at least once a day. Storage thereafter
should be above 20°C (68°F). The required concentrations are:
i) 250 ppmh ( _+ 15 ppmh)
ii) 1500 ppmh ( +_ 150 ppmh)
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20 Spec: A.3.
3. Recommended number of gases
a) for evaluation testing
i) 7 equally spaced concentration values of calibration gases
per range
ii) bottled zero gas
iii) 2 concentrations of hexane/propane conversion factor
checking gas
iv) 1 cylinder of 14% CO
v) 1 cylinder of 100 ppm NO
b) for in-use systems
i) one span gas concentration between 70-95% of fs on low
range for each HC and CO analyzer. For standardization, 1.5%
CO and 600 ppm C are prefered.
ii) purified room air zero gas
iii) for systems that use a CO analyzer, on span gas concen-
tration between 8 to 12 percent CO,,. For standardization 10%
C0~ is prefered.
c) for periodic check (i.e. State audit) of in-use systems (final
guidelines will appear in follow-on EPA recommendations for State
audit quality assurance programs)
i) a minimum of 3 concentrations per range for each analyzer,
or
ii) one concentration for each, cutpoint and 207(b) standard
(if applicable) with a concentration value within 10 percent
of the cutpoint (need not exceed 5 concentration levels), and
iii) bottled zero gas
iv) one cylinder of 14% CO
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Spec: B.I.-2.
B. Gas Cylinders
1. In-use Span gases
a) Gas cylinder should be of a "1A" or "T" size. Single blend
capacity (HC in air or CO in N ) is generally around 200 cubic
feet at 2000 psi. Dual blend (HC and CO in N2> is generally
around 160 cubic feet at 1600 psi.
b) All cylinders shall meet DOT specifications for "1A" or "T"
cylinders.
c) Gas cylinders smaller (or larger) than the "1A" or "T" size may
be used provided that:
±) The analysis system gas useage for the various operations
(i.e., gas span, leak check, etc.) is such that the span gas
in the smaller (or larger) cylinder will last at least 6
months when using the recommended frequencies of those opera-
tions. Span gas useage rate should be identified during the
evaluation testing.
ii) The analyzer manufacturer performs a source study to
insure adequate availability of the smaller (or lar-ger)
cylinders in sufficient quantity to service analyzers using
that bottle size.
iii) Regardless of the results of the source study, if the
smaller (or larger) cylinders are not available in some
areas, or if those cylinders become unavailable at a later
date, the manufacturer must make available a retrofit kit
that will allow the use of a "1A" or "T" cylinder.
d) Disposable cylinders may not be used.
2. Concentration Label
A semi-permanent label shall be affixed or attached by the Certifying
Laboratory to each gas cylinder with the following information.
a) Name of the Gas Blender
b) Name of the Laboratory Analyzing the Gas Blend
c) Cylinder I.D. number
d) Date of Analysis
e) Traceability to NBS or to other certified EPA Mobile Source
Standard
f) Statement of Impurities (See accuracy and composition require-
ments)
g) Gas Concentration
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Spec: C.I.-4
C. Durability Criteria
1. Vibration and Shock Test
(See Test Procedure)
2. Sample Line (see Test Procedure)
a) Line crush
Sample Handling System Temperature :
Effect
a) Unloaded System - 20 minutes
600°F sample
inlet
b) Load System - continuous at 1000°F
sample inlet
Filter Check (see Test Procedure)
a) 2 hr sample time :
b) Sample until "low flow"
indication
a) span shift: 2% fs LS
b) All analyzer and system
performance checks must
be met.
i) No visible failure or
deterioration
ii) Meet leak check
specifications
iii) Meet response time
specifications
a) No visible failure
or deterioration.
b) Meet leak check
specification.
c) Meet response time
specification.
d) Meet HC hang-up
specification.
i) Low Flow Not Activated
ii) Meet Leak Check
specifications
iii) Meet Response Time
Check
iv) Meet HC hang-up check
i) Time until "low flow"
system activates or 20
hr of sample.
ii) Until the low flow
system activates the
system response time
must be met.
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23 Spec: D.l.-3.d.)
D. Design Requirements
1. The analysis system shall be designed with a design goal of a 5
year minimum useful life. Useful life has terminated when the analysis
system can no longer be repaired to meet the specifications in this
document at a cost of less than 60 percent of the replacement cost at
the time of repair.
2. NAME PLATE Permanently Located and Readable.
a) Analyzer System Manufacturer
i) Name
ii) Address
iii) Phone number (customer service)
b) Analyzer Model Number and Serial Number
c) Date of Analyzer System Assembly
3. Sample System
a) Sample system components should be designed for intermittent
sampling (20 minutes out of 10 hr.) of 600°F inlet (to probe)
exhaust temperature. Such systems shall be designated "Unloaded"
analysis systems. Systems designed for continuous duty with a
minimum of 1000°F inlet (to probe) exhaust temperature, and proper
sample handling equipment (i.e. water removal and/or heated lines)
may be called "Loaded" analysis systems.
b) The type of system (Loaded or Unloaded) shall be permanently
attached and prominently displayed in large letters.
c) The materials used in the sample handing system shall not alter
the exhaust sample. Some examples of non-reactive materials are
teflon , viton , stainless steel, silicone rubber (red), and in
some areas nylon . Some examples of reactive materials are,
brass, copper, and tygon .
d) Water Trap;
i) A water trap shall be included in the sample system. The
trap shall be self draining, visible to the operator, and the
sample system shall be designed to prevent condensable water
from occurring in the sample system downstream of the water
trap. The following options may be used but are not re-
quired.
1, Option 1: A dry-basis measurement is permitted if
the absolute moisture content entering the analyzer is
less than the saturation moisture content at a sample
gas temperature of 7°C (45°F). Ice traps or refrigera-
tors are permitted.
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24 Spec: D.3.e)-5.a)
2. Option 2: Electronic correction to a "dry-basis"
reading is permitted if the temperature and pressure of
the sample after the water trap is measured and the
sample is assumed to be saturated at the measured temp-
erature. The water correction system must be deacti-
vated for leak checks.
e) Particulate Filter
i) A particulate filter(s) shall be included in the sample
system.
ii) The major or pre-filter (if used) shall be located in a
manner that allows convenient filter element replacement.
iii) The proper direction of flow for the filter body(s) and
element(s) (if applicable) shall be indicated in a manner
that is easily discernible.
. iv) The filter body shall be designed to provide leak free
operation with normal filter element changing frequency for
the lifetime of the analyzer, or a parts list of specific
replaceable parts shall be listed in the maintenance manual
as parts that may contribute to sample system leaks.
v) If a filter(s) is on the vacuum side of the system, all
manuals and filter element replacement instructions shall
indicate that the system should be leak checked every time a
filter element is changed. A similar message should be
located on or near the filter body(s).
vi) The filter element and filter system shall be designed
to prevent particulates larger in size than 5 microns from
entering the sample cell of the analyzer. The location of
this optical bench 5 micron filter is up to the manufacturer
and may be on the pressure or vacuum side of the system. If
this filter only filters sample gases passing through the
analyzer, the manufacturer may elect to have an additional
filter prior to the system pump(s). The particulate size of
this optional filter is at the discretion of the manufactur-
er. Verification of filter particulate size removal is
permitted to be determined by the filter manufacturer using
standardized ASTM or Filter Industry procedures.
4. Sample Pump
The sample pump shall be designed for at least a 2000 hour life of
continuous duty.
5. Sample Probe
a) The probe must sample at least 16 inches from the end of the
tailpipe or dilution adaptor.
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25 Spec: D.5.b)-6.c)
b) The probe shall have a flexible portion that will allow the
probe to be inserted in a 1% inch O.D. tailpipe. Assume the
tailpipe has a 3 inch radius 90° bend beginning 4 inches from the
end of the tailpipe.
c) The probe shall be designed for easy servicing and/ or replace-
ment.
d) A leak proof dilution adapter (tailpipe extender) shall be
provided. Multiple adapters may be used.
e) The tailpipe extender shall be able to be attached to the
vehicle within 60 seconds.
f) The tailpipe extender shall be designed to allow the attachment
of standard service center building exhaust evacuation systems
without affecting the vehicle or measurement process. The pres-
sure at the end of the tailpipe or extender should be within ±2
inches of water of the ambient barometric pressure.
g) The tailpipe extender shall not alter the sample and the mater-
ial shall conform to D.3.C.) of this chapter.
h) The probe and tailpipe extender shall have sufficient hardware
(insulated handles, etc.) that will allow the user to insert,
attach, or remove the probe or the dilution adapter safely and
conveniently.
i) The probe or tailpipe extender shall be designed in a manner
that will prevent the probe or extender from being removed from
the vehicle unintentionally.
j) All probes should have a smooth surface near the probe tip
before the flexible portion of the probe to be used for sealing of
the span gas adaptor necessary for field or on-board leak checking
(gas comparison) or response time checking equipment. For
standardization the sealing surface should be ^ inch in outside
diameter and % to 1 inch long.
6. Sample Line
a) The sample line shall be sufficiently flexible at the tempera-
tures to be encountered during vehicle testing (See Section G)) to
allow normal inspection operations. Pliability need only be
demonstrated at the lower operating environmental temperature.
b) The sample line shall not be longer than 25 feet nor shorter
than 15 feet (excluding^ the probe). For standardization 20 feet
is prefered.
c) The portion of the sample line in contact with the exhaust
gases shall not alter the exhaust sample, and shall minimize HC
hangup, due to absorption, adsorption, desorption, outgassing,
etc.
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26 Spec: D.6.c)-7.h)
d) The manufacturer must state the estimated useful life of the
sample line In the instruction manual.
7. Analyzer Spanning System
a) Minimum Gas Spanning Frequency; The analyzer shall be designed
for routine gas spanning every 180 hours (once per week).
b) Recommended Gas Spanning Frequency: It is recommended that the
analyzer be gas spanned after:
i) every "power on" and warm-up sequence, and
ii) every 4 hours of "power on" condition when testing.
c) Minimum Electrical Spanning Frequency: All analyzers shall be
electrically spanned every hour when testing.
d) Optional Spanning Frequencies: Three equipment options may be
substituted for the 4 hour recommended gas spanning frequency.
(These options may reduce the use of span gas). Details of these
options are found in subparagraphs m), n), and o) of this section.
e) The analyzer shall be routinely spanned with flowing zero
(purified room air) and span gases. A convenient port for peri-
odic (i.e. audit) spanning with bottled zero gas shall be pro-
vided. A separate audit port for audit gas shall be provided to
alleviate the necessity to disconnect the span gas in order to
perform the audit test. The audit port should interconnect the
span system downstream of the span/zero switching valve.
f) The gas spanning operation must allow the operator to easily
correct for changes between the gas span point gain and the elec-
trical span point gain. In all cases the electric span point gain
is the parameter that must be changed such that the new electric
span point gain setting will cause the analyzer to read the span
gas properly. For manual operation, the manufacturer shall pro-
vide a step by step sequence in the operators manual equivalent to
the automatic system recommended for decentralized units.
g) If the analyzer is equipped with multiple ranges, there shall
be convenient access for audit or service personnel to adjust or
trim the scale factor between ranges. When trimming the scale
factor, start on the highest range and work down. When spanning
the analyzer, start on the lowest scale and work up.
h) When the analyzer is initially installed at a new sight, the
analyzer span gain for a proper gas span shall be logged in the
analyzer's log book. A numbered span adjustment knob may be used
for this purpose, or the physical gain adjustment of the front
panel controls may be limited to the values listed. The limited
gain control option shall include visable reference to the range
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27
Spec: D.7.i)-7.1)
of initial adjustment and to the range approaching mandatory main-
tenance. Generally this mandatory -maintenance would include
cleaning of the sample cell. Criteria: If the adjusted span
gain for any subsequent spanning operation exceeds 140% of the
initial value logged in the book, the operation manual shall
indicate that the system is approaching a mandatory maintenance
criteria. The operation manual should indicate operation of the
analyzer with gain settings exceeding 150% of the logged initial
value constitute improper operation and the analyzer needs repair.
The user (State, contractor, owner/inspector, etc.) is responsible
for proper operation of the equipment.
i) The span point for all analyzers shall be between 70 and 100
percent of full scale on the lowest range. For standardization
the preferred values are 1.5% CO and 600 ppm C3.
j) Appropriate valves, switches, and electrical controls shall be
provided that will allow the operator to conveniently select zero,
span, or sample gases, and zero and span the analyzer.
k) Determination of Test Value.
i) The analyzer shall have a selector switch or button (with
indicator) labeled "Sample" or "Test".
ii) Activation of the "sample" switch shall cause the ana-
lyzer system to begin integrating or averaging the analyzer
response 17 seconds after the switch is activated, and con-
tinue integrating the analyzer response to a flowing sample
for the next 15 seconds. The sample and hold circuits can be
either analog or digital. Digital sample rates shall be at
least 10 hertz. An optional start integration time is de-
scribed in Chapter VIII paragraph D.2. The option may be
used if the criteria are met.
iii) The analyzer read-out device shall display the Inte-
grated value, and hold the display until reset. An indicator
light shall signal the operator when the integrated value is
displayed.
1) Span cylinders
i) For stand alone centralized inspection analyzers (a condi-
tion determined by the State or Contractor) and all decen-
tralized analyzers, the analysis system shall Include a
structure for safely securing two "1A" or "T" size cylinders
(i.e. 160-200 cubic foot bottles) unless the manufacturer has
elected to use a different cylinder size as outlined in
Section B. on gas cylinder specifications. Appropriate regu-
lator (s) and lines shall be provided for one dual blend (HC
and CO in N ) cylinder. If the system Includes a C02 ana-
lyzer, regulator (s) and lines shall be provided for one
cylinder of CO span gas.
-------
TO
Spec: D.7.m)-7.o)
ii) For centralized systems utilizing multiple analyzers in a
single location, the analyzer manufacturer need only supply
span gas and bottled zero gas ports on the analyzer. The
user (i.e. State or Contractor) is responsible for the span
gas manifold system including lines and regulators.
iii) Optional Span Cylinder Location; An analyzer manufac-
turer may elect to not locate the span bottles on the ana-
lyzer structure by providing a bottle cart or rack to secure
the span bottle(s). The bottle cart must safely secure two
"1A" or "T" size cylinders (unless other bottle sizes are
used). Non-reactive quick disconnect connections must be
used on the span gas lines between the cart system and the
analyzer.
m) Optional Spanning System la; The analysis system may provide
temperature and pressure compensation to the analyzer output and
spanning system. The compensation shall be based on sample cell
gas pressure and sample cell inlet gas temperature. If such a
system is used, and verified by subsequent checkout, an electrical
span check may be substituted for the "power on" and 4 hour gas
span checks, but not for the weekly gas span checks. During
analyzer checkout, only one gas span check is allowed as part of
the Initial analyzer set-up prior to the initiation of the entire
check out procedure. An electric span shall be substituted for
all gas spanning operations in Chapter XI (unless otherwise
noted). Additional tests will be required in order to verify the
accuracy and linearity of the compensation network at the various
atmospheric pressures and temperatures required by the performance
specifications (Chapter VII, Secion E).
n) Optional Spanning System Ib; A pressure and temperature moni-
tor system would be considered to be in compliance with the pro-
vision of optional spanning system la, if the system monitors the
sample cell gas pressure and inlet gas temperature continuously.
If these parameters exceed 4 inches H20 and/or 10°F difference
from the most recent gas span, the analyzer would subsequently and
boldly alert the operator of the need for a new gas span check
(for manual systems). For decentralized systems, the compensation
system shall perform as above as well as prevent further operation
of the analyzer (unless the computer automatically gas spans the
analyzer without any operator input).
o) Optional Spanning System 2; The basic accuracy and precision
of the analysis system may be significantly better than the speci-
fications put forth in this document. In such a case, the analy-
sis system may be capable of meeting the specifications of this
document without any pressure and/or temperature compensation of
the analyzer output and spanning system. If such a claim is made,
and verified by subsequent checkout, an electrical span check may
be substituted for the "power on" and 4 hour gas span checks, but
not for the weekly gas span checks. During analyzer check out,
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29
Spec: D.8.-9.
only one gas span check is allowed as part of the initial analzer
set-up prior to the initiation of the entire checkout procedure.
An electric span shall be substituted for all gas spanning opera-
tions in Chapter XI (unless otherwise noted). Additional tests
will be required in order to verify the accuracy of the analysis
system at the various atmospheric pressures and temperatures
required by the performance specifications (Chapter VII, Section
E).
8. Analyzer Ranges
a) Low-Range : i) 0-400 ppmh HC
ii) 0-2% CO
b) High Range : i) 0-2000 ppmh HC
ii) 0-10% CO
c) An analyzer may use one range for HC or CO corresponding to the
high range values provided that the low range portion (0-400,
0-2%) meets all of the analyzer specifications as if that portion
were a separate range. During check out of the system the 0-400
ppmh and 0-2% portions of the high scale shall be treated as a low
range scale.
d) All analyzer read out devices (digital or analog) shall be
appropriately scaled and capable of reading negative values up to
-5 percent of full scale for each range regardless of operational
mode (sample, span, leak check, etc.). The sample operational
mode may prevent negative readings if a diagnostic switch allows
such readings (negative ones) to occur for diagnosis of analyzer
problems.
e) All manufacturer's literature shall provide an explanation on
the difference between ppm propane and ppm hexane. All formal or
technical reports should clearly identify measured HC results as
ppm hexane.
f) All multi-range analyzers shall have range indicating lights
that clearly indicate which meter scale is to be read. The lights
shall be of sufficient intensity and color that will allow an
operator to identify the range selection in sunlight from a dis-
tance of 15 feet.
g) Additional analyzer ranges may be used provided that they meet
all specifications pertaining to the recommended ranges.
9. System Grounding
a) All systems shall have a 3 wire power cord with a 3 prong
grounded plug.
b) The manufacturer's representative should check upon initial
installation to insure that the system is properly grounded to
prevent ground loops from interfering with the analyzer.
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10
Spec: D.10.
10. System Vents
a) No restrictions such as flowmeters may be placed downstream of
any analyzer vent (a series analyzer flow path is permitted)
unless the system can detect potential changes in restriction
(i.e. sticking flowmeter), and
i) alert the operator of the problem which would require a
new gas span and/or repair of the component causing the
restriction, or
ii) use automatic compensation of the analyzer readout device
for the change in restriction.
b) A change in restriction that will cause a 3 percent of point
change in the analyzer response shall activate the alert system.
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31
Spec: E.I.-3
E. Analyzer Performance Specifications
1. Calibration Curve Uncertainty including Bias errors, Precision
errors, and Historesis (Per test procedure):
a) 5% of point (i.e. True value of reading).
b) Below 100 ppmh HC or 0.40% CO the uncertainty specification
need not apply.
c) If the analyzer prevents the operator from reading below 10
percent of full scale on the high scale, then the uncertainty
specification need not apply to that portion of the high scale.
d) If necessary to obtain the desired accuracy at the low end of
the CO scale, the uncertainty of the CO calibration curve above 6%
CO may be expanded to 10% of point.
2. Resolution:
a) analog meters - 2.5% fs on each range
b) digital meters (last digit increment by 1)
i) xxxx ppmh
ii) x.xx% CO
3. Compensation:
a) Altitude compensation (mandatory): The analyzer shall have
sufficient zero and span adjustment to allow the spanning of the
analyzer at any altitude between 0 and 7000 feet. The external
span adjustment may be limited in range as long as a clearly
marked internal adjustment will make up the difference.
b) Compensated Systems (optional): (For systems that choose to
use pressure and temperature compensation of analyzer read-out and
span system)
i) The temperature compensation network shall provide accu-
rate results over the ambient temperature range specified in
Section G of this chapter as well as exhaust gas temperatures
up to 49°C (120.2°F). (Units with heated sample cells are
excluded from this requirement).
ii) The pressure compensation network shall provide accurate
and linear results (analyzer read-out) over a pressure range
of + 2 inches HgG from the local barometric pressure. The
system shall be capable of operation between 24 and 32 inches
HgA. Test points about which the pressure shall be varied in
order to ascertain the accuracy and linearity of the compen-
sation network are 24.5, 28.5, and 30.0 inches HgA.
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32 Spec: E.I.-3
c) Non-compensated Systems (optional): For those analysis systems
that claim pressure and temperature compensation is not necessary,
the analysis system shall be tested to the specification outlined
in step b) for pressure and temperature compensated systems.
d) For optional systems b) and c), all testing (unless noted)
shall be conducted with those systems (b or c) active and opera-
tional.
4. Zero Drift:
a) ±2% fs L.S. for 1 hour
b) ±2% fs L.S. for 30 minutes if equipped with automatic zeroing
system (auto zero must be disabled for zero drift check).
5. Span Drift: ±2% fs L.S. for 1 hour.
6. Noise (clean environment): ±0.5% fs L.S. (Total 1% peak to peak)
(See Test Procedure)
7. Sample Cell Temperture:
a) It is preferred that the sample cell and gases (sample and
span) immediately upstream of the sample cell be heated. If the
sample cell is heated the minimum sample temperature shall be 49°C
(120.2°F).
b) If the sample cell is not heated, the analysis system must
compensate for temperature affects on the gas (sample or span)
measurement process as in Section 3.
8. Interferences
a) Gases
Analyzer
HC CO
i) 14% CO : 1.5% fs L.S. 1.0% fs L.S.
^ (RR = 37500)* (RR = 1500)
ii) Saturated Water : 1.5% fs L.S. 1.0% fs L.S.
@ 40°C (101°F) (RR = 20,000) (RR = 800)
iii) 100 ppm NO : 1.5% fs L.S. 1.0% fs L.S.
(RR = 50) (RR = 100)
b) Electronic
i) RFI : 1.0% fs L.S.
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33
Spec: E.9.
: 1.0% fs L.S.
: 1.0% fs L.S.
: 1.0% fs L.S.
: 1.0% fs L.S.
ii) VHP
±±±) Induction
iv) Line Interference
v) Line Voltage and
Frequency Variation
(90-130 v A.C.)
(59-61 hz)
The operation manual shall contain an easily identifiable
warning recommending against the use of portable generating
equipment to supply power for the analysis system unless the
user verifies that the power generating equipment will main-
tain the voltage and frequency within the above specification
under the load conditions experienced during analyzer use.
vi) Static Electricity
(Analog meters only)
1 meter division or 2^% fs L.S.
whichever is greater. (Deter-
mined at the lowest and dryest
temperature used during the
evaluation testing).
* RR = Rejection Ratio
9. Propane to Hexane conversion factor: The mean propane to hexane
conversion factor for each analyzer sold as a pass/fail inspection
analyzer shall be between 0.48 and 0.56 for each test point. The mean
value shall be known at the 90% confidence level to at least two signi-
ficant figures. The confidence interval shall not exceed a 0.01 incre-
ment in the correction factor. Due to the exceptional hang-up char-
acteristics of hexane a laboratory quality sample/span system that
bypasses the analyzers' sample/span system may be used. All components
in the laboratory system that come in contact with the hexane gas used
for determination^ of the factor shall be either clean stainless steel
or teflon (viton valve seats are permitted).
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34 Spec: F.I.-5
F. Sample System Performance Specifications
1. Maximum Sample cell mean pressure difference
between gas spanning and sampling : 4" H90
2. Maximum sample cell
Pressure variation during sampling : 6" H_0
(pump pulsations)
3. Maximum sample cell mean
pressure difference between normal
flow and low flow indication : 4" H?0
4. Response Time : 14 sec. maximum
Inlet of probe to 95% fs L.S. (@ low flow indication)
(See Test Procedure)
5. System Leakage:
a) The analyzer shall not be used if a leak(s) exists in the
vacuum side of the system that causes a measurement error of
greater than 3% of the true sample value.
b) The pressure side of the sample system shall be leak free as
determined by a "bubble" leak-check method (not to be used in the
field).
c) The vacuum side leak-check method shall consist of a comparison
of the span gas response introduced through the span network to
the response of the same span gas introduced through the probe and
sample line. In the future with demonstrated and historical data,
other leak-check techniques may be accepted or equivalent to the
gas comparison leak-check.
d) The analyzer manufacturer shall provide a convenient system to
introduce the span gas to the probe in a manner such that the
pressure in the sample line during leak-checking is equal to or
slightly below the pressure occurring in the sample line during
testing. It is preferred that the leak checking equipment be
mounted on the analysis system structure.
e) The analyzer manufacturer shall provide, in the operating
manual, step by step leak-checking procedures including calcula-
tions.
f) Gas comparison leak-checks on the vacuum side of the system
shall be performed every 180 hours (once a week). Abbreviated
leak-checks (e.g. vacuum decay, etc.) may be used on a daily
basis, if desired, but not as a substitute for the weekly gas
comparison test.
g) The user (i.e. State, or Contractor, or owner/inspector) is
responsible for implementing policies and procedures to insure
that the leak-check procedures and frequencies are adhered to.
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35 Spec: F.6.
6. HC Hang-up:
a) The HC analyzer response to room air sampled through the probe
and sample line shall be less than 20 ppm C6 prior to testing a
vehicle or the test is void.
b) The analyzer manufacturer may provide an Internal back flushing
sequence or chemical (or catalytic) purification equipment (i.e.,
oil and impurity removal, etc.) for external compressed air back
flushing in order to reduce the time required for hang-up check-
ing.
c) A receptical on the analyzer structure may be provided for the
HC hang-up check to preclude the probe from sampling room air in
close proximity to the floor.
d) The analyzer manuacturer shall provide, in the operating man-
ual, step by step hang-up checking procedures.
e) The operation manual shall caution the operator that an exces-
sively long time (5 to 10 minutes) to reduce the hang-up level to
below the 20 ppm C6 HC level indicates that system maintenance may
be required.
f) The user (i.e. State or Contractor) is responsible for imple-
menting policies and procedures to insure that the hang-up proce-
dures are conducted prior to every test.
g) For evaluation testing only, the hang-up level should be less
than 20 ppm C6 within 10 minutes of beginning • any hang-up check
(including 2 hr sample) specified in the evaluation tests.
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36 Spec: G.I.-2.
G. Operating Environment
1. The analysis system shall meet all system specifications required
in Chapter VII under the following conditions (see Test Procedure):
a) Ambient Temperature: Between 35°F to 110°F
b) Ambient Relative Humidity:
i) Range of field operation: 0% to 100% condensing
(i.e. raining or dense fog).
ii) The user shall prevent direct impingement of condensed
ambient moisture (rain) on the analyzer (i.e. DO NOT LET IT
RAIN ON THE ANALYZER).
iii) Range of Testing: 15% to 85%
iv) Maximum Test Point: 80% to 85% RH @ 105°F(±5°)
WARNING: Testing in environmental
chambers at relative humidi-
ties above 85% with tempera-
tures above 90°F may be
HAZARDOUS to human life! The
primary hazard is due to heat
loading on the human body's
cooling-system (i.e. perspi-
ration effectiveness) leading
to heat induced body dis-
functions. Precautions should
be taken to avoid overexposure.
A secondary hazard is a potential
electric shock hazard due to
the high moisture content of
the test cell.
2. The analysis system shall be able to be stored at any temperature
between -20°F to 130°F with no adverse effects on subsequent analysis
system performance.
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37 Spec: H.I.-2.
H. Fail-Safe Features
1. Warm-Up
a) The analyzer must have a warm-up lock-out feature with indica-
tors. No specific warm-up time is specified.
b) The lock-out feature shall prevent operation of the printer (if
used) and read-out meter until the system is warmed up.
c) The lock-out feature shall be activated:
i) When system power is turned on. The lock-out shall stay
on until the zero drift is stabilized. The manufacturer must
condition the lock-out on analyzer parameters, and may not
use clock time as a sole criteria to determine warm-up condi-
tion. Verification of proper zero stabilization is deter-
mined by observing the zero drift over a 5 minute period
after the lock-out feature deactivates. The zero drift
during this 5 minute period may not exceed one-half of the
zero drift specifications in Section E. If digital sampling
of the zero level is used, the sample rate shall be at least
10 hertz. Analog observation of zero drift is permissable.
ii) if the sample cell is heated and the cell temperature is
less than that specified in section E,
2. Low-Flow
i) The analyzer must have a low sample flow indicator. Inspecting
a vehicle when the low flow indicator is activated constitutes
improper operation. The user (i.e. State, contractor, or owner/
inspector) is responsible to insure proper operation.
ii) The low flow indicator shall be activated when the sample flow
rate is decreased to a point that would not allow the analysis
system to meet the response time specifications.
iii) The low flow indicator shall be prominently displayed, and
shall be observable from at least 15 feet away.
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38 Spec: I.
I. System Correlation (on Raw Exhaust) to Laboratory Analyzers
1. All analyzers (comparison to NDIR Analyzer per Test Procedure)
a) Precision Test: A P <_5%
b) Slope Test: 0.95 <_ m <_ 1.05
c) Ratio of Modal Ave: 0.90 < R <1.10
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39
Spec: J.I.-4
J. Manuals
1. Each analyzer shall be delivered with one each of the following
manuals.
a) Easy Reference Operating Instructions
b) Operation Instruction Manual
c) Maintenance Instruction Manual
d) Initial Start-up Instructions
2. The manuals shall be constructed of durable materials, and shall not
deteriorate as a result of normal use over a five year period.
3. The easy reference operating instructions:
a) shall include brief step by step instructions for
i) Gas Spanning
ii) Electrical Spanning
iii) Leak Checking
iv) Inspection testing with probe insertion, anti-dilution,
HC hang-up, and reading test value instructions.
b) may be stenciled or decaled to the analyzer frame in a location
convenient to the operator, may be printed on plastic flip-up
cards attached by a ring or chain to the analyzer, or may use some
other communication means that allows repetitive and convenient
use of the instructions by the operator. All easy reference
materials shall be attached to the analyzer.
4. The operating instruction manual must contain :
a) The analyzer model
b) A more detailed step by step sequence of pre-test procedures
(span, leak check, probe insertion, HC hang-up etc.)
c) Sampling procedures
d) The operating manual shall provide to the operator more insight
into the specific procedures than the easy reference instruction
are capable of because of their brevity. It may be appropriate to
include diagnostic instructions in the operating manual.
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40 Spec: J.5.-7
5. The maintenance manual must contain:
a) Name, address, and phone number of the manufacturer's customer
service and maintenance center at the home office and nearest
field office.
b) Name, address, and phone number of the nearest service center
authorized to make warranty adjustments.
c) A technical description of the system.
d) A separate section that clearly outlines the required or antic-
ipated maintenance schedule. The schedule shall be broken down
into maintenance intervals such as weekly, monthly, etc.
e) A separate section that provides a step by step sequence for
each maintenance requirement.
f) A list of replaceable items such as filters, probes, etc. with
part numbers, and the estimated service life of each component
(normal operation).
g) A list of recommended spare parts that the user should main-
tain.
h) Functional mechanical and electrical schematics.
i) The manufactuer's warranty provisions.
6. Each manual shall be attached to the analyzer in a manner that will:
a) allow convenient storage,
b) allow easy use, and
c) prevent accidental loss or destruction.
7. The manufacturer's service representative is responsible for logging
all repairs performed by the manufacturer or their representative with
appropriate description in the log book.
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VIII. Additional System Sepcifications Recommended for
Decentralized Inspection Programs (computer operation)
The following fail-safe features are specified in order to prevent improper
operation of analysis systems used for decentralized systems. However, they
could be useful in centralized systems as well. In general these features
will probably require an on-board microprocessor. When using a micropro-
cessor, an alpha numeric keyboard and readout may be substituted for various
switches, buttons, or indicators specified in the following sections.
Microprocessor units may also elect to print void test results instead of
interlocking the printer. In that case, the word "VOID" must prominantly
and/or superimposed over the data. All valid test results must clearly
indicate the validity of those results.
A. Automatic zero/span check
1. The analyzer shall not have any adjustments available to the oper-
ator for adjusting zero or span point for either the gas spanning
operation or the electrical spanning operation. These adjustments
shall be available in the anti-tamper box described in this chapter.
2. The analyzer shall have a selector switch or button (with indicator)
labled "gas span". Activation of the switch shall cause the analyzer
to automatically perform the gas spanning sequence with flowing zero
and span gas consistent with the requirements for the manual analyzer
spanning system specified in Section D.7. of Chapter VII.
3. If the analyzer is equipped with multiple ranges, there shall be
convenient controls or automatic sequence available to audit or service
personnel to adjust or trim the scale factor between ranges. The
adjustment shall be based on the analyzer's response to calibration gas
concentration values. The concentration values shall be between 70 and
100 percent of each range. When trimming the scale factor, start on
the highest range and work down. When spanning, start on the lowest
range and work up.
4. The analyzer shall have a selector switch or button with indicator
light labeled "electrical span". Activation of the switch will cause
the analyzer to automatically perform an electrical zero and span
operation consistent with the requirements for the analyzer manual
spanning system specified In Section D.7. of Chapter VII.
5. The automatic gas spanning operation shall be completed as quickly
as possible (preferably less than 90 seconds) once the "gas spanning"
switch is activated.
6. The concentrations of span gas shall be entered via switches or
other convenient means to the following resolution:
HC = XXXX ppm propane
CO = X.XX% CO
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42
The switches or Interlock that allows the entering of the span gas
values shall be in an anti-tamper box as described in this chapter.
7. When the analyzer is initially installed at a new sight, the ana-
lyzer gain for a proper gas span shall be automatically stored for
future reference. If the adjusted span gain for any subsequent span-
ning operation exceeds 150 percent of the initial stored value, the
analyzer readout shall be electronically driven to 100% of full scale,
(or an error message displayed), the printer, if used, shall be pre-
vented from printing, and an indication of analyzer malfunction shall
be prominently displayed. If the adjusted span gain for any subsequent
spanning operation exceeds 140 percent of the stored value, an indi-
cation to the operator of pending maintenance shall be provided.
8. If the adjusted span voltage changes by more than 20 percent of the
most recent span voltage, the analyzer read-out shall be electronically
driven to 100% of full scale, the printer if used shall be prevented
from printing, and an indication of analyzer malfunction shall be
prominently displayed.
9. The analysis system shall include suitable timers to insure that the
spanning frequencies are met. The timing systems shall also prevent
use of the analysis system by driving the readout devices to full scale
(digital units may substitute an error message for the analyzer read-
ing) and prevent the printer from printing. Performing the appropriate
spanning operation shall automatically reset the timer for that speci-
fic type operation regardless of the time elapsed since that operation
was last performed. The options listed in the next Section (Section B.
Automatic Leak-Check) may be used in leui of a battery back-up for
"power-off" time keeping.
10. The microprocessor system shall compute the equivalent hexane (HC)
span set point based on the input propane value, and the analyzer
propane/hexane conversion factor. The auditor shall have access to the
computed value.
11. All features In Section D.7. of Chapter VII shall apply to the
automatic span system.
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43
B. Automatic Leak-Check
1. The sampling system shall have an automatic leak checking system for
the vacuum side of the system.
2. The analyzer shall have a timer that will allow the analyzer to
operate for 180 calendar hours (once per week) between leak checks. If
after 180 hours the system is not leak checked, or the system fails a
leak check, the analyzer readout shall be electronically driven' to 100
percent of full scale (Digital units may substitute an error message
for the analyzer reading), and the printer shall be prevented from
printing. The following options are available in any combination:
i) Option 1; If a full leak check is performed every time the
power is turned on, and an operating time clock insures that the
leak check frequency is met in the event that the power is left on
continuously, then an auxilliary power supply (i.e. battery) for
the clock during power off is not necessary.
ii) Option 2; In leui of a real time clock with battery back-up,
the system may count the number of times the "power-on" switch
(not the stand-by switch) is turned on. The weekly check will be
assumed to have been met if the analyzer system requires a leak
check (as specified) after every 6 times the power on switch is
turned on (i.e. leak check begins with the 7th time of power on).
An operating time check is necessary in the event the power is
left on continuously.
3. Activation of the automatic leak-check system shall cause the ana-
lyzer to automatically perform (or check) a span sequence, automati-
cally introduce span gas to the probe, compare the difference between
the span and probe readings, and make a pass or fail determination.
4. A leak-check pass or fail indicator shall be prominantly displayed.
5. All features in Section F.5. of Chapter VII apply to the automatic
leak-check system.
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44
C. Automatic Hang-Up Check
1. The analyzer shall have a selector switch or button (with indicator
light) labeled "Hang-up Check" or "Purge."
2. Activation of the "Hang-up" switch shall cause the analyzer to
automatically sample room air through the sample line and probe. The
"Hang-up Check" system shall continue to sample room air until the HC
response is less than 20 ppm C6.
3. Any combination of sampling room air and/or internal back flushing
may be used to achieve a 20 ppm C6 HC level when sampling room air.
4. When HC level stabilizes below 20 ppm C6, a prominently displayed
indicator shall notify the operator that it is permissable to begin a
test sequence. The analyzer shall be precluded from beginning the test
sequence until the hang-up check is met.
5. Activation of the "sample" switch shall be prevented unless a suc-
cessful hang-up check has been performed since the last activation of
the test sequence, and the HC analyzer has not experienced an HC level
greater than 20 ppm C6, or
6. All requirements in Section F.6. of Chapter VII shall apply to the
automatic HC hang-up check.
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45
D. Automatic Read System
1. The analyzer shall have a selector switch or button (with indicator
light; labeled "Sample" or "Test".
2. Activation of the "sample" switch shall cause the analyzer system to
begin integrating or averaging the analyzer response 17 seconds after
the switch is activated, and continue Integrating the analyzer response
to a flowing sample for the next 15 seconds. The sample and hold
circuits can be either analog or digited. Digital sample rates shall
be at least 10 hertz. If the manufacturer identifies that the response
time to 99 percent of a step change is less than 17 seconds, the manu-
facturer may select any time between the 99 pecent time and 17 seconds
to begin the integration. If the manufacturer elects this option, the
integration start time must be boldly visable on the front of the
analyzer. Failure to meet this new response time during field audit
checks will constitute a failure of the audit.
3. The analyzer read-out device shall display the integrated value, and
hold the display until reset. An indicator light shall signal the
operator when the integrated value is displayed. The automatic test
sequence may interact with the automatic read system to reset the
display at appropriate times or within the test sequence.
4. The analyzer shall be prevented from printing the integrated value
until the "sample" switch is activated and the "sample" cycle is com-
pleted.
E. Dual Tailpipes
1. The system shall have the capability to automatically calculate the
average reading for dual tailpipes.
2. The dual tailpipe system shall use integrated test values from the
automatic read system for averaging.
3. Activation of the dual tailpipe system shall allow two activations
of the automatic read system without activating the hang-up check
interlock.
4. The dual tailpipe system shall display the average value on operator
command, and hold the value until reset.
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46
F- Automatic Test Sequence
1. The microprocessor must be capable of being programmed for the
standard sequences listed in Table VIII-1. These test sequences do not
cover all of the possible combinations that may exist. On the con-
trary, these sequences were limited in number specifically in an effort
to standardize procedures and equipment.
2. The system must store the cutpoints for each mode of the test
sequence used. The operator may only use State accepted criteria for
selecting cutpoints. It is recommended that the following criteria be
used.
a) Vehicle Model Year
b) Type of Vehicle
i) Light-Duty Vehicle
ii) Light-Duty Truck
iii) Heavy-Duty Gas Truck
c) Spare Channel (fuel type)
d) Spare Channel (Catalyst-non-catalyst, California-non-California)
3. Access to the test sequence programming, and cutpoint values and
applications shall be limited to State Auditor by means of the anti-
tamper ing provisions in this chpater.
4. The system must identify the integrated value for each mode, make a
pass or fail decision on that mode, and either immediately print the
results or store the results until the completion of the test sequence.
5. If the test sequence Includes more than one mode, the system shall
use the pass or fail decision from all applicable modes to determine an
overall pass/fail determination.
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47
Table VIII-1
Recommended I/M and 207(b)
Test Sequences *
ooooooooo om .. M 00000000
Test Type Non Idle Idle
**
Pre-81 - Pass/Fail
Post-81 (unloaded) 2500 RPM, Pass/Fail Pass/Fail
Post-81 (loaded) 30 MPH, Pass/Fail Pass/Fail
* Test sequences may be preceeded by any type of preconditioning desired
if the sequence is performed manually. The Automatic test sequence
feature in the analyzer need only follow the test modes described after
the test sequence is initiated by the operator.
** Pre-1981 model year vehicles.
*** 1981 and later model year vehicles.
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48
G. Printer
1. The analysis system shall have a printer that provides the consumer
and the inspector (not required with Automatic Data Collection option)
a receipt with the following information:
a) Date (the printer may use manually input values for the date).
b) Inspection Facility Number or Instrument Serial Number (value
may be input manually).
c) Inspection Test Number (may be sequenced by initiation of
Automatic Test Sequence).
d) Applicable cutpoints or standards for HC and CO for each test
mode.
e) Integrated vehicle test values for HC and CO for each test
mode.
f) An overall pass or fail indication as well as for each test
mode.
H. Vehicle Diagnosis
1. For the purpose of vehicle diagnosis and/or repairs, the analyzer
shall have a selector switch or button (with indicator light) labeled
"Vehicle Diagnosis" or "Vehicle Repair".
2. Activation of the "Vehicle Diagnosis" switch shall allow the ana-
lyzer to continuously monitor the vehicle exhaust.
3. The printer, or any automatic data collection system, shall be
prevented from operating anytime the analysis system is in a "Vehicle
Diagnosis" status.
4. Auxilliary analog trend meters may be used provided that they are
deactivated for inspections.
I. Anti Tampering
1. The anti-tampering feature shall be designed to prevent intentional
tampering with the analysis system.
2. All switches or entry access for automatic zero/span check adjust-
ments, anti-dilution limits, span gas concentration values, diagnostic
switches, etc. shall be contained in a box or other tamper-proof mech-
anism with provisions for an inspector's seal. A gummed label with the
inspectors initials and date which must be torn to gain access, or a
braided wire and crimped lead seal (or similar device) would be suffi-
cient for sealing.
3. The tamper-proof system must allow convenient access by an in-
spector.
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49
J. System Diagnostic Testing
1. Switches or other devices for rendering any fail-safe or automatic
feature inoperative for the purpose of diagnostic or performance check-
ing of the analyzer are permitted.
2. These switches (or devices) must be contained in a tamper proof
box(es) or other tamper-proof mechanism with provisions for a seal.
3. All analyzer systems must be shipped with all fail-safe and auto-
matic features operating, and the defeat systems sealed.
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50
IX. Optional Features For The Inspection Analyzer
The optional features listed are intended to provide more capability, flexi-
bility, or convenience. They include automatic data collection (ADC),
additional printer capability, anti-dilution equipment, loaded mode kit, and
an engine tachometer. The first option (ADC) would generally require a
computer operated analyzer. The remainder of the options are applicable to
both the computer and manually operated analyzer.
A. Automatic Data Collection
1. The automatic data collection (ADC) feature may store data on a
magnetic cassette tape, magnetic disc, or other storage medium.
2. Any external peripheral devices (phone line modems, external storage
medium, etc.) should have an RS232 port.
3. Any external transmission of data should be coded in ASCII with a
maximum of 80 column records.
4. Other coding, formating, and blocking should follow industry ac-
cepted standards.
5. The ADC storage medium should store data on at least 150 vehicles.
6. The stored data shall be available only to an appropriate inspector,
and shall be protected by a seal (see anti-tampering).
7. A keyboard shall be available to allow the following types of data
to be entered. As indicated, the system may automatically (Auto) enter
certain data:
a) Date (Auto)
b) Vehicle license plate number
c) VIN
d) Vehicle type (LDV, LOT, HDG, etc.)
e) Vehicle make
f) Vehicle model
g) Vehicle Model Year
h) Emission Family Number (from emission label)
i) Odometer
j) Fuel type (gasoline, gasohol, methanol, ethanol, propane,
hydrogen, spare channel, etc.)
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51
k) Test Facility I.D. (Auto)
1) Facility Inspection Test Number (Auto)
m) Type of test. (Initial test, first retest, second retest, etc.)
n) Applicable cutpoints for HC and CO for each applicable test
mode (Auto).
o) Anti-dilution decision criteria (ie. air pump, no air pump,
etc.)
8. The processor shall enter the following data on the tape.
1) Integrated vehicle test values for HC and CO for each test mode.
2) An overall pass or fail indication for HC and CO as well as for
each test mode.
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52
B. [Deleted]
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53
C. Anti-Dilution (Optional for all systems)
The anti-dilution feature can perform three useful functions: 1) most
important, it can serve as an indicator of vehicle exhaust system leaks that
would cause the measured emission values to be lower; 2) it can be used to
identify dilution of the sample due to either probe placement or tailpipe
extender leaks; and 3) it could potentially be used to insure decentralized
operators actually insert the sample probe (or attach the extender), and
actually measure vehicle exhaust samples.
1. The anti-dilution feature shall identify vehicle exhaust system
leaks and sample dilution.
2. The preferred technique for identifying leaks is monitoring the C0?
levels in the exhaust. Other techniques that can demonstrate improved
sensitivity to leaks may be used.
3. At least three lower limit C0« values shall be capable of being
used.
a) no air pump
b) air pump
c) spare channel
4. The resolution of the C0« span gas values entered shall be, XX.X%
co2.
5. The CO- values shall be entered by switches or-other convenient
means.
6. The (XL analyzer shall meet all of the analyzer specifications in
Chapter VII between CO values of 6% and 14%. (CO interference speci-
fication does not apply). Specifications in Chapter VIII apply to
computer analyzers.
7. If the CO £ is less than the lower limit, the analyzer output shall
be electronically driven to 100% of full scale (digital units may
substitute an error message for the analyzer reading), the printer (if
used) shall be prevented from printing, and an indication of exhaust
system dilution shall be prominently displayed.
8. The analyzer operator shall be able to select one of the three
lower limits.
9. The analyzer shall be prevented from reading auto exhaust until one
of the three limits is selected.
10. If a printer is used, the CO limit for the test shall be printed.
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54
D. Loaded Mode Kit
The analyzer specifications in the previous chapters generally apply to an
analyzer used for unloaded or idle testing. The analyzer designed for the
unloaded test can usually be transformed into a loaded mode analyzer with
suitable changes to the sample handling system. In some cases these changes
could possibly be retrofitted in the field on analyzers originally manufac-
turered as unloaded analyzers. The following items should be included in a
loaded mode analyzer.
1. A refrigeration or ice bath water trap. The water trap must lower
the sample gas temperature to 7°C (45°F). Suitable measurement devices
and indicators must alert the operation on the status of the unit. No
testing should be performed at sample temperatures above 7°C. With the
manual system, the operator is responsible to Insure that this criteria
is met. The computer analyzer would need an interlock with the sample
gas temperature measurement device in order to become responsible for
proper procedures.
2. All components upstream of the refrigeration trap must be capable
of running continuously at 1000°F inlet (to the probe) exhaust tempera-
ture. Some of the equipment that would possibly require upgrading for
the higher temperatures would include the tailpipe extender and connec-
tor, the probe, and the sample line.
3. The loaded mode analyzer may require additional sample filtration.
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55
E. Engine Tachometer
The two speed idle test (see Table VIII-1) meaures emissions at idle and at
an elevated engine speed, usually 2500 RPM. The standard idle emission
test, in most cases, preconditions the engine at 2500 RPM. In some in-
stances, it may be beneficial to have engine speed measurement capabilities
included within the emission analyzer system. The tachometer should have
the following features.
1. The tachometer accuracy should be stated in the maintenance manual.
2. For "propane gain" diagnostic work, tachometer accuracy should be
±30 RPM between 400 RPM and 1200 RPM. The precision or repeatability
should be 5 RPM or less, and the resolution should be 1 RPM.
3. The preferred transducer is a clip-on magnetic induction pick-up.
4. The computer operated emission analyzer should monitor the engine
speed during the high speed portion of the two speed idle test. If the
engine speed exceeds selected limits during the test, the computer
shall void the test.
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56
X. Future Improvements for the Inspection Analyzer
A. Introduction
During the development of these specifications, several areas of emission
analysis were identified that should be improved. Improvements in these
areas have not been included in the specifications (and hence do not impact
State adoption of the recommended specifications) because of either the cost
or the lead time required to develop the improved technology. The staff
feels, however, that those involved with emission measurements should be
aware of the need for these improvements. The following discussions are
directed mainly at the analyzer manufacturers in hopes of stimulating the
necessary developments or improvements. The staff feels such improvements
can be economically feasible by 1987.
B. Improvements in Water Removal
There are two forms of emission measurements. A "wet-basis" measurement is
the form the exhaust leaves the tailpipe fully laden with moisture from the
combustion of the fuel. Most NDIR type emission analyzers cannot accept
this moisture, and still operate properly. Unless substantial improvements
or breakthroughs are made in emission measurement equipment, it is expected
that NDIR type analyzers will be used in the future. Therefore, practical
systems must provide a method for removing the moisture before it enters the
analyzer. If absolutely all of the water is removed from the sample, the
measurement becomes a "dry-basis" measurement. The difference between a wet
and a dry measurement of the same sample can be as much as 10 percent (dry
is higher).
Practically all current field analyzers use a momentum type water trap. The
moisture removal efficiency of this type of trap ranges from 0 to 100 per-
cent depending on the ambient temperature and the sample temperature. Some
state inspection lanes use a refrigeration trap which generally has a mois-
ture removal efficiency between 98 to 100 percent. In order to allow for
these variations in moisture removal efficiency, it was elected to base the
1984 Federal H.D. truck idle standard on a dry-basis measurement. For this
same reason, it is expected that the projected 207(b) standards would be
dry-basis values.
These decisions- effectively consider all I/M inspection measurements as
dry-basis measurements even though many may not be. In order to eliminate
some of this measurement variation in the future, it is reasonable to expect
that all measurements be taken on a truely dry-basis. Two techniques are
suggested for dry measurements. The first is similar to portions of the
loaded mode kit. Adoption of this improvement would be to remove a poten-
tial 7 to 10 percent variability in I/M measurements.
Analyzers manufacturered after January 1987 should include one of the fol-
lowing.
1. A refrigeration or ice bath water trap. The water trap must lower
the sample gas temperature to 7°C (45°F). Suitable measurement devices
and indicators must alert the operation on the status of the unit. No
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57
testing should be performed at sample temperatures above 7°C. With the
manual system, the operator is responsible to insure that this criteria
is met. The computer analyzer would need an interlock with the sample
gas temperature measurement device in order to become responsible for
proper procedures.
2. Electronic compensation. Electronic correction to a "dry-basis"
reading is permitted if the temperature and pressure of the sample
after the water trap is measured and the sample is assumed to be satu-
rated at the measured temperature. The water correction system must be
deactivated for leak checks.
C. Improvements in EC Measurement
Non-dispersive Infrared (NDIR) HC analyzers used in I/M programs are limited
in their ability to measure all of the hydrocarbons in the exhaust. Current
NDIR analyzers tend to measure only straight chain paraffinic hydrocarbons,
although they do have some response to aromatics and aldehydes. The lack of
response to these non-paraffinic compounds is the primary reason why the
Federal Test procedure changed from NDIR HC measurement to FID (flame ioni-
zation detector) HC measurement 8 years ago (1972).
Even though catalyst vehicles tend to produce more paraffinic hydrocarbons
than non-catalyst vehicles, chromatographic analysis of gasoline-fueled
engine exhaust indicates significant quantities of the non-paraffinic hydro-
carbons exists even in catalyst vehicles. The very same compounds that
current NDIR HC analyzers have difficulty in measuring.
Changes In fuel composition can also affect the composition of the hydro-
carbons in the exhaust. An increase in aromatics components in the fuel as
in unleaded premium gasoline will tend to increase the aromatic content of
the exhaust hydrocarbons. A similar situation occurs with gasohol which
tends to increase the content of aldehydes in the exhaust concentration.
Since the NDIR HC analyzer has poor response to both aromatics and alde-
hydes, the current NDIR analyzers will generally show a decrease in hydro-
carbons when the true hydrocarbon content as measured by an FID would gener-
ally remain about the same.
Considering these facts, one may question the necessity or the wisdom of HC
measurements with an NDIR analyzer in an I/M program. Even though the NDIR
HC analyzer does not measure all of the HC in the automobile exhaust, a
reduction in the paraffinic hydrocarbon levels can in many cases be indica-
tive of a reduction of the other classes of hydrocarbons. Further, the
criteria for determining State cutpoints is the number of vehicle failures,
and the reduction of just the paraffinic hydrocarbons from the failed vehi-
cles still contributes to a reduction in ambient air hydrocarbons.
One may also question why an FID is not specified in the first place. The
reason is that an FID is a complex piece of laboratory equipment that re-
quires a mixture of hydrogen and helium for fuel, and purified air for an
oxidizer. At this point, the staff is somewhat skeptical about the compat-
ability of current FIDs in an I/M test environment.
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58
In the past there has been no incentive to improve the field measurement
techniques for HC measurements. Considering the possible impacts of fuel
switching and the fact that if a program continues past 1987 the program may
not be as effective as predicted in the SIP, the staff feels that the HC
measurement techniques should be improved.
The improvements can be accomplished through better response characteristics
of current NDIR's, or new less complex HC measurement techniques could
possibly be developed. In order to provide an incentive for this advance-
ment In technology, beginning in January 1987, it is recommended that all
I/M analyzers correlate to an FID HC analyzer by the procedures provided.
To assist in the degree of correlation that is technically feasible, it is
recommended during the verification of current analyzer performance that an
additional test be performed that compares the I/M HC analyzer to an FID.
Review of the NDIR/FID correlation data generated by the accreditation
procedures is recommended prior to the implementation of the 1987 specifi-
cations.
Analyzers produced after January 1, 1987 should correlate to an FID in the
following criteria (see Test Procedure):
1. Precision Test: A p £ 5%
2. Slope Test: 0.317 1 m 1 0.350
3. Ratio of Modal Ave: 1.80 < R < 2.20
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59
XI. Evaluation Procedures
The test procedures in this chapter are presented to provide a consistent
interpretation of the specifications. Although the procedures do provide a
step by step sequence, and it is expected that the evaluator follow that
sequence; they are not a substitute for common sense or good engineering
judgment. Some analysis system designs may simply not be amenable to cer-
tain portions of certain test procedures. Further, there may be ways to
simplify or combine certain test procedures. In those cases, the evaluator
should review the procedure as written, determine the important conceptual
aspects and parameters of the procedure, and then use engineering judgment
in testing the analyzer.
The basic test procedure should be performed in a laboratory that has exper-
ience in automotive emission testing. The general testing should be con-
ducted at an ambient temperature between 68°F and 86°F. Section G requires
certain test procedures to be conducted at other ambient temperatures.
If either of the non-gas spanning alternatives are used (See Chapter VII,
Section D.7.). only one gas span operation is permitted for the entire
Chapter XI procedure, unless otherwise noted. This single gas spanning
operation shall take place during the initial start-up procedure. Elec-
trical span will be substituted for all other gas spanning operations.
Analytical gases, of course, will be required for check out of the system.
The procedures as written are generally independent of tolerance specifica-
tion values. Following each test procedure, a reference value corresponding
to the values given in Chapter VII through X will be given in parenthesis.
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60 TP:A.
A. Traceability of Analytical Gases
The traceability of analytical gases may or may not be part of the analyzer
manufacturer's responsibility. The choice belongs to the state. However,
it is recommended that the analyzer manufacturers not be held responsible.
Further, gas manufacturers should meet certain performance standards and be
accredited as acceptable vendors, or the state should provide a distribution
service.
The traceability of all gases used in the I/M program is of course impor-
tant. Traceability implies not only blending, but analyzing the gases
properly. Although operating the analysis equipment properly seems like a
trivial task, some very prominent laboratories have sometimes been embar-
rassed by subsequent review of their procedures and analysis of their
blended gases.
In order to provide the automobile manufacturers with what EPA/OMSAPC con-
siders proper traceability procedures, the Emission Control Technology
Division (ECTD) of EPA is publishing a Recommended Practice for Assuring Gas
Traceability to NBS. This procedure, which is a compilation of internal EPA
procedures, is applicable to I/M analytical gases.
The entire traceability procedure may involve more equipment than a state
may wish to become initially involved with. A minimum recommendation for
I/M programs is that each gas blender or certifying laboratory that is
allowed to supply gases for pass/fail I/M systems should follow the ECTD
procedure. The next step would be a continuing quality-audit of each sup-
plier by the state using the correlation portion of the traceability proce-
dure.
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61 TP:B,
B. Gas Cylinder Specifications
No test procedures required.
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62 TPrC.l.
C. Durability Test Procedures
1. Vibration and Shock Test Procedure
The vibration and shock test procedure is designed to evaluate the
ability of the analyzer to tolerate moderate use in a service facility.
Although a simple span test is performed, the real test of the analyzer
is the ability of the analyzer to meet the remaining performance checks
to follow this test.
a) Equipment Required
i) Candidate instrument.
ii) One span gas between 70 and 90 percent of full scale on
the low range, and bottled zero gas.
iii) A special test floor 6 feet by 10 feet. The top of the
floor shall be elevated 2 inches off the test facility floor.
The floor shall consist of an expanded metal grating with
diamond shape openings measuring 1 x 3.7 inches or equiva-
lent. The length of the floor in the direction of the "short
way of the diamond" shall be 10 feet.
b) Test Sequence
i) Warm up the analyzer.
ii) Span the analyzer on the low range with the span gas per
the manufacturer's recommendations (on the test floor).
iii) Record the zero response and the span response.
iv) Roll the instrument the entire length of the test floor
in the direction of the "short way of the diamond", and off
the end of the test floor onto the facility floor.
v) Pull the analyzer back onto the test floor.
vi) Repeat steps iv) and v) a total of six times.
vii) Check the zero response, and if necessary adjust the zero.
viii) Check the gas span response (do not adjust the analyzer
span).
ix) Record the zero response and the span response.
c) Calculations
i) Subtract the zero response from the span response in step
b) iii) (span before).
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63 TP:C.l.
ii) Subtract the zero response from the span response In step
b) viii) (span after).
iii) Subtract the value calculated in step c) ii) from the
value calculated in step c) i) (span shift).
d) Acceptance Criteria
i) If the value calculated in step c iii) is less than or
equal to the vibration and shock span shift specifications,
then the vibration and shock performance is acceptable.
ii) Reference value: 2%
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64 TP:C.2.
2. Sample Line Crush Test Procedure
The sample line crush test is to be repeated under the "operating
environment" testing. If space is a problem in the environmental
chamber, after stabilization, the sample line can be removed from the
chamber to perform the crush test. If the line is removed from the
chamber, the crush test must be performed and the line returned to the
chamber within 3 minutes.
a) Equipment Required
i) Candidate instrument.
ii) One span gas between 70 and 90 percent of full scale on
the low range, and bottled zero gas.
iii) One vehicle with at least 4000 pound curb weight.
b) Test Sequence
i) Stabilize the sample line at the prevailing ambient
temperature.
ii) Warm up the analyzer. Do not turn on the sample pump.
iii) Span the analyzer with the analytical gases.
iv) Leak-check the system.
v) Stretch out the sample line across a solid (concrete etc.)
floor.
vi) Drive across the sample line so that at least one front
and one rear vehicle wheel passes over the sample line.
vii) Back over the sample line so that at least one front and
one rear vehicle wheel passes over the sample line.
viii) Repeat steps vi) and vii) twice.
ix) Leak-check the system.
x) Check for "low flow" indication.
xi) Check for visible failures, kinks, deterioration, etc.
c) Calculations
(none)
d) Acceptance Criteria
i) If the system passes the leak check (step ix) , does not
indicate a "low flow" condition (step x), and shows no sign
of permanent deformity (step xi), then the crushability.
performance of the sample line is acceptable.
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65 TP:C.3.
3. Sample Handling Temperature Effect
a) Equipment Required
±) Candidate instrument with tailpipe extender.
ii) Catalyst equipped vehicle.
iii) Thermocouple read-out device.
iv) Type "J" or type "T" thermocouple (1/16 inch diameter
MgO shielded and grounded).
v) One HC span gas between 70 and 90 percent of full scale
on the low range, and bottled zero gas.
vi) Associated fittings.
b) Test Sequence
i) Locate a point approximately 1 inch upstream from the end
of the probe, and weld a thermocouple boss on the extender
(top side when installed on vehicle).
ii) Install the thermocouple into the extender to a distance
approximately half-way between the extender wall and the
sample probe.
iii) Warm up the analyzer.
iv) Span the analyzer with the analytical gases.
v) Leak check the system.
vi) With the vehicle running, locate a position away from
the vehicle to avoid vehicle contamination, and measure
the background HC levels with the sample system. Record
the background HC levels.
vii) Install the extender on the vehicle.
viii) Adjust the vehicle to elevate the exhaust gas tempera-
ture (as measured by the thermocouple) to at least 300°C
(572°F)and not more than 360°C (680°F).
ix) As soon as the exhaust gas has stabilized between 300°C
and 360°C, start a timer and begin sampling.
x) After twenty (20) minutes at the temperature in step
viii), remove the probe or extender, and simultaneously start
another timer.
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66 TP:C.3.
xi) Immediately move the probe or extender to the location
previously used to measure background HC, while continuing to
sample room air and simultaneously start a timer.
xii) Continue to sample room air until the analyzer response
is 20 ppmh. Record the elapsed time to 20 ppmh.
xiii) Introduce zero gas into the analyzer through the gas
spanning system. Record the response.
xiv) Introduce span gas into the analyzer through the gas
spanning system. Record the response.
xv) Leak check the system.
xvi) Check for "low flow" indication.
xvii) Check for visible failure, melted or deformed parts,
deterioration etc.
xviii) When the testing is completed, remove the thermocouple
and cap the boss with a leak proof cap.
c) Calculations
i) Compute the difference in span response between step b)
xv) and b) iv) (span drift).
d) Acceptance Criteria
i) The value computed in c) i) must be less than the span
shift specifications. (Reference value: 2%).
ii) The system must pass the leak check.
iii) A low flow condition shall not be indicated.
iv) No portion of the system shall show signs of heat damage.
v) The elapsed time recorded in c)xii) shall be less than the
HC hang-up specifications. (Reference value: 10 minutes).
vi) If the above criteria are met, then the high temperature
performance of the system is acceptable.
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67 TP:C.4.
4. Filter Check and Hang-up Test Procedure
The filter check procedure consists of two phases - a 2 hour check, and
a check to determine the useful life of the filter. It is intended
that all subsequent system check procedures are to be conducted with a
filter and sample system that have experienced at least 2 hours of
exhaust sample as defined in this procedure. Therefore, the second
part of the filter test may be performed after the other tests are
complete if a log of sampling time during the other tests is main-
tained. If during subsequent testing, a low flow indication occurs due
to filter loading, the filter may be changed, the filter life recorded,
and testing may continue with a new filter. After 20 hours of sample
through one filter, the test may be discontinued.
a) Si uipment Req uired
±) Candidate instrument.
ii) Test vehicle that can create a hydrocarbon sample of at
least 1500 ppmh with a spark plug wire removed or the choke
partially closed.
iii) Clean sample filter.
iv) One span gas between 70 and 90 percent of full scale on
the low range, and bottled zero gas.
b) Test Sequence
i) Install a clean sample filter.
ii) Warm up the analyzer.
iii) Span the analyzer with the analytical gases, and leak
check the system.
iv) With the vehicle running, locate a position away from
the vehicle to avoid vehicle contamination, and measure
the background HC levels with the sample system. Record the
background levels.
v) Attach the tailpipe extender to the vehicle.
vi) Insert the probe into the extender and begin sampling.
vii) Begin the vehicle malfunction.
viii) As soon as the emissions exceed 1500 ppmh, begin a timer,
ix) Maintain the HC level above 1500 ppmh, and sample the
vehicle for two (2) hours.
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68 TP:C.4.
x) During the two hours monitor the "low flow" indication.
xi) After two hours, remove the probe or extender, and simul-
taneously start another timer.
xii) Immediately move the probe or extender to the location
previously used to measure background EC. If the analyzer
has an HC hang-up check cycle, immediately begin the check
cycle.
xiii) Continue to sample room air until the analyzer response
is 20 ppmh. Record the elapsed time to 20 ppmh.
xiv) Introduce zero gas into the analyzer through the gas
spanning system. Record the response.
xv) Introduce span gas into the analyzer through the gas
spanning system. Record the response.
xvi) Leak check the system.
xvii) Alternatives: 1) at this point the filter testing may
be suspended in order to complete the other tests. A log
book of sampling time must be kept for the other tests, or 2)
reinsert the probe into the extender, and continue testing
until the "low flow" system activates or until 20 hours of
sample time is reached (whichever occurs first), or 3) repeat
the 2 hour filter check at the end of the performance testing
of the analyzer, then continue testing until the "low flow"
system or 20 hour criteria are met.
xviii) Record the elapsed time to "low flow" indication (if
appropriate).
c) Calculations
i) Compute the difference in span response between step b)
xv) and b) iii) (span drift).
d) Acceptance Criteria
i) The value computed in c) i) must be less than the span
shift specifications. (Reference value: 2%).
ii) A low flow condition shall not occur during the 2 hour
check.
iii) The elapsed time recorded in c) xiii), shall be less
than the HC hang-up specifications. (Reference value: 10
minutes).
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69 TP:C.4.
iv) If the above criteria are met, then the performance of
the filter is acceptable.
v) If the total elapsed time to "low flow" activation is not
less than 70 percent of the analyzer manufacturer's estimate
of sample life-time of the filter, the manufacturer's esti-
mate is acceptable. If the elapsed time is less than 70
percent of the estimate, the manufacturer's estimate shall be
revised downward.
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TP:D.l.-6.
D. Design Requirement Inspection and Test Procedures
1. Useful Life; No test procedure.
2. Name Plate; Visual observation.
3. Sample System;
a) Visual observation.
b) Visual observation.
c) Visual observation.
d) See "Analyzer Gaseous Interference and Noise Test Procedure,"
Chapter XI, Section E.8.
e) i) Statement by analyzer manufacturer on partical size and
element lifetime.
ii) See "Filter Check and Hang-Up Test Procedure." (Chapter
XI, Section C.4.)
4. Sample Pump; No test procedure.
5. Sample Probe; Test procedures self-explanatory or features can
be determined by visual observation.
6. Sample Line;
a) Flexibility Test Procedure: Perform the normal motions re-
quired to use the sample line for testing vehicles. Perform this
test at the lowest environmental temperature used for check out
under Chapter XI procedures. Make a determination about whether
the sample line can be used without a great deal of difficulty at
the condition tested. If it is determined that the sample line is
not sufficiently flexible, then the manufacturer may suggest more
objective test procedures and/or more data to demonstrate compli-
ance.
b) Self-explanatory Test Procedure.
c) Visual observation.
d) Statement by analyzer manufacturer.
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TP:D.7.-10.
7. Analyzer Spanning System Test Procedure; The performance and
acceptance of the spanning system will generally be determined by the
system's performance on the other test procedures conducted during the
evaluation procedures, and visual observation of the equipment fea-
tures. In other cases (such as event timers), the test procedures are
self-explanatory, and are not listed. The evaluation of the test value
integration will take place as part of the correlation testing in
Section I of this chapter.
8. Analyzer Ranges; Visual observation.
9. System Grounding; Visual observation and manufacturer's instruc-
tions to service representatives.
10. System Vents; If restrictions downstream of the analyzer exit are
apparent, a test procedure shall be devised that evaluates the analyzer
performance under restricted conditions. Test Procedures E.3.a) (Alti-
tude Compensation) and F.I. (Sample Cell Pressure Variation, Low Flow,
and Response Time) shall be used for guidance.
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72
TPrE.l.
E. Analyzer Performance Test Procedures
1. Calibration Curve Test Procedure
a) Equipment Required
i) Candidate instrument
ii) Seven or more calibration gases for each range of each
analyzer roughly equally spaced over each range.
ili) Zero gas
iv) Associated valves and fittings
b) Test Sequence
i) If necessary, follow the manufacturer's instructions for
initial start-up and basic operating adjustments.
ii) Warm up the analyzer
iii) Zero the analyzer with the zero gas
iv) Span the analyzer with one of the calibration gases. The
span point should be approximately 80 to 90 percent of full
scale of the low range
v) Recheck the zero. If the zero has shifted, repeat steps
iii), iv), and v) a maximum of one more time.
vi) Do not adjust the zero or span controls on the analyzer
for the remainder of the test.
vii) Introduce the calibration gases in ascending order of
concentrations beginning with the zero gas. Record the
analyzer response to each concentration value.
viii) After the highest concentration has been introduced and
recorded, introduce the same calibration gases to the ana-
lyzer in a descending order. Include the zero gas. Record
the response of the analyzer to each gas. Record negative
zero responses (if any) as they occur as negative values.
ix) Repeat steps vii), and viii) a total of five times.
c) Calculations
i) For hydrocarbon analyzers, compute the hexane equivalent
(ppmh) of each calibration gas by multiplying the concen-
tration value in ppm propane (ppmp) by the propane/hexane
conversion factor listed on the analyzer.
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73 TPrE.l.
ii) Compute the standard deviation(s) and mean(x) of the
analyzers response for each concentration of calibration
gases. Include both upscale responses and downscale re-
sponses to the same calibration gas. Zero may be a special
case and not amenable to the calculations.
iii) For all concentration values except the highest value,
multiply the standard deviation(s) by a factor (K) of 2.5.
iv) Multiply the standard deviation(s) of the analyzers
response to the highest concentration by a K factor of 3.5.
v) Compute the following for each concentration
1) Jl = x + Ks
2) y2 = x - Ks
vi) Compute the uncertainty(U) of the calibration curve for
each concentration by:
concentration value-y
concentration value
where i = 1, or 2 U ±
d) Acceptance Criteria
i) Identify the maximum uncertainty for each range.
ii) If the maximum uncertainty is less than or equal to the
uncertainty specification (Chapter IV, Section E) , (plus or
minus), the calibration curve is acceptable. If the uncer-
tainty is greater than specification, the calibration curve
is not acceptable. (Reference values: 5% of point above 100
ppmh and 0.4% CO, 10% of point above 6% CO is permissable if
necessary)
iii) If the calibration curve is not acceptable, then the
instrument manufacturer should undertake an engineering study
to identify the cause of the problem prior to continued
testing or introduction of the analyzer to the commercial
ma rk e t.
iv) After the cause of the problem is identified and the
analyzer is repaired or adjusted this test should be re-
peated.
e) Repeat steps b) , c), and d) for each range of the analyzer.
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74
TP:E.3.a.
2. Analyzer Resolution
a) Analog Meters: The resolution is determined by the Interval of
the smallest graduation of the meter face for each analyzer range.
b) Digital Meters: The resolution is determined by the increment
of the least significant digit of the meter readout for each
range.
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75 TP:E.3.a.
3. Compensation Test Procedures
a) Altitude Compensation Test Procedure (not required for analyzers
with Spanning Alternative, 1 or 2)
±) Equipment
1) Candidate instrument.
2) One pressure gauge or manometer that reads in absolute
pressure (e.g. 20 to 32 in. HgA) with 1% accuracy.
3) One differential pressure gauge (0 to 15 inches of
water).
4) One flowmeter (0-20 cubic feet per hour (CFH)).
5) Two needle valves.
6) One vacuum pump (greater than 20 CFH@ 24 in. HgA).
7) One span gas 70 to 90 percent of full scale on the low
range.
8) One Tedlar sample bag.
9) Associated lines and fittings (non-reactive).
ii) Test Sequence
This procedure is written around parallel HC and CO ana-
lyzers, and should be performed on each analyzer. If the
analyzers are in a series configuration, then an additional
pressure gauge (s) will be required, but the test can be
performed on both analyzers at the same time.
If the analyzer manufacturer states in writing that the
structural integrity of the sample cell will not withstand
the pressure differential associated with this test procedure
at 24 inches of HgA, the altitude check must be made in an
altitude chamber. In an altitude chamber only steps 8), 9),
10), 14), 15), 16) and 20) need be performed at the pressures
specified in step 13) and 18).
1) Identify the sample line entering the sample cell of
each analyzer.
2) Install a tee fitting in the sample line immediately
upstream of the sample cell (as close as practical).
Install the tee with branch pointing up.
3) Immediately upstream of the tee install one of the
needle valves.
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76 TP:E.3.a.)
4) Identify the exhaust line from the sample cell and
install two tees or a 4-way cross fitting in. the line
with the branches pointing up.
5) Downstream of the tees or cross fitting install the
flow meter.
6) Attach a differential pressure gauge to the tee
upstream of the sample cell and one of the exhaust tees.
Attach one gauge across each analyzer in a series sys-
tem.
7) Attach the absolute pressure gauge to the second
exhaust tee.
8) Warm up the analyzer.
9) Check for leaks.
10) Sample room air through the sample line with the
needle valve wide open.
11) Record the sample cell exhaust flow rate, the dif-
ferential pressure across each analyzer, and the abso-
lute pressure.
12) Attach the second needle valve after the flowmeter.
13) Adjust both the needle valves to obtain an absolute
pressure of 31 inches of HgA, the sample differential
pressure recorded in step ii), and a flow-rate of not
less than 2 cfh.
14) Fill the sample bag with the span gas, and introduce
the span gas from the bag into the sample line.
15) Use the analytical gases to set the zero and span of
the analyzer. Note if internal adjustments were re-
quired to span the analyzer.
16) Return to sampling room air.
17) Attach the vacuum pump to the exhaust line after the
second needle valve with an appropriate length of line,
and open both needle valves.
18) Turn the vacuum pump on, and adjust both needle
valves to obtain an absolute pressure of 24 inches of
HgA, the same differential pressure recorded in step
11), and a flow rate approximately the same as recorded
in step 11).
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TP:E.3.a.)
19) Refill the sample bag if necessary, and introduce
the span gas into the sample line from the bag.
20) Use the analytical gases to set the zero and span of
the analyzer. Note if internal adjustments were re-
quired to span the analyzer.
iii) Calculations (none)
iv) Acceptance Criteria
1) If the analyzer can be spanned properly in steps ii)
15), and ii) 20, and the technique required to span the
analyzer under these conditions is identified in the
owner's manual, then the altitude compensation network
is acceptable.
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78 TP:E.3.b.)
b) Pressure and Temperature Compensated Analyzer Test Procedure
i) Testing concepts: This test procedure is to be performed
in order to identify the performance of any pressure or
temperature compensation systems under the various environ-
mental conditions that may be encountered during vehicle
inspection testing. In general, temperature compensation
will be evaluated during the basic check-out (68°F to 86°F)
and during the more hostile environmental temperature tests
specified in Section G. No other special testing would
normally be necessary.
In order to evaluate pressure compensation systems, addi-
tional testing is necessary. If the analyzer manufacturer
can make a case that testing the pressure compensation system
in a manner similar to the procedure specified in Chapter V
Section E.3.a) (altitude compensation) will represent actual
analysis system operating conditions in the field, then that
procedure (E.3.a) may be used for check-out. If a sufficient
case cannot be made, and a suitable alternative test proce-
dure cannot be determined, then performance evaluations of
the pressure compensation system must be carried out in an
altitude chamber. The pressure compensation test shall be
conducted at each environmental temperature condition speci-
fied in Chapter V. The tests shall be performed on each
range of each analyzer.
ii) Test conditions: The test conditions shall consist of
three basic barometric pressures about which excursions in
pressure shall be made. The values are:
Basic Test Excursion
Point (inches HgA) Points (inches HgA)
24.5 24.0, 26.5
28.5 26.5, 29.-5
30.0 28.5, 31
iii) Test Sequence
1) Identify the concentration value that provides the
greatest uncertainty in measurement as determined by
Test Procedure E.I). Obtain a calibration gas at that
level (same bottle if possible).
2) Set up the test equipment for one of the three test
points.
3) Warm up the analyzer.
4) Gas span the analyzer with a different calibration
gas between 80 and 90 percent of full scale on the low
range and bottled zero gas. An electrical span would
not be substituted for the gas span in this step.
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79 TP:E.3.b.)
5) Leak check the system.
6) Alternately introduce zero gas and the calibration
gas identified in step 1) through the sample probe until
a total of three readings are obtained and recorded for
each test step.
7) The test steps for the 24.5 in HgA test point are:
Test Step Action
24.5 gas span
24.0 3 readings
24.5 3 readings
26.5 3 readings
24.0 3 readings
26.5 3 readings
24.5 3 readings
24.0 3 readings
24.5 3 readings
26.5 3 readings
8) Repeat steps 4) through 6) at the 28.5 inch HgA test
point. The test steps for this test point are:
Test Step Action
28.5 gas span
26.5 3 readings
28.5 3 readings
29.5 3 readings
26.5 3 readings
29.5 3 readings
28.5 3 readings
26.5 3 readings
28.5 3 readings
29.5 3 readings
9) Repeat steps 4) through 6) at the 30.0 in. HgA test
point. The test steps for this test point are:
Test Step Action
30.0 gas span
28.5 3 readings
30.0 3 readings
31.0 3 readings
28.5 3 readings
31.0 3 readings
30.0 3 readings
28.5 3 readings
30.0 3 readings
31.0 3 readings
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TP:E.3.b.)
iv) Calculations
1) For each test point, compute the standard devia-
tion (s) and mean (x) for the 9 readings obtained at each
pressure level.
2) Multiply each standard deviation by a K factor of
2.6.
3) For each pressure level at each test point, compute
the following:
y = x + Ks
y2 = x - Ks
4) For each pressure level at each test point, compute
the uncertainty (U) of the measurements based on the
calibration gas used in step iii) 6) from:
_ concentration value-y. 1_„
concentration value
where 1=1,2
v) Acceptance Criteria
1) Identify the maximum uncertainty
2) If the maximum uncertainty is less than or equal to
the uncertainty specification (Chapter VII, Section E),
(plus or minus), for the basic analyzer calibration
curve, the pressure compensation is acceptable. If the
uncertainty is greater than specification, the pressure
compensation is not acceptable. (Reference Values: 5%
of point above 100 ppmh and 0.4% CO, 10% of point above
6% CO is permissable if necessary).
3) If the pressure compensation is not acceptable, then
the instrument manufacturer should undertake an engi-
neering study to identify the cause of the problem prior
to continued testing or introduction of the analyzer to
the commercial market.
4) After the cause of the problem is identified and the
analyzer is repaired or adjusted this test should be
repeated.
vi) Repeat steps iii), iv), and v) for each range of the
analyzer.
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81 TP:E.3.c.)
c) Non-Compensated Systems
i) If an analyzer manufacturer claims that the measurement
uncertainty specifications (Chapter VII, Section E.) can be
met without pressure and/or temperature compensation, this
claim can be verified by the test procedure in Section E.
3.b) of this Chapter. (Reference Values: 5% of point above
100 ppmh and 0.4% CO, 10% of point above 6% CO is permissable
if necessary).
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82
4. Analyzer Zero and Span Drift Test Procedure
(See Test Procedure Section H.I.a), Warm-up Lock-out Test Procedure),
a) Equipment Required
i) Candidate instrument.
ii) One span gas between 70 to 90 percent of full scale on
the low range.
iii) One cylinder of zero gas.
iv) One chart recorder (one megohm impedance or greater) with
approximately a 10 to 12 inch wide chart.
b) Test Sequence
i) Begin the test sequence with an analyzer that is turned
off, and has stabilized at the prevailing ambient temperature
for at least 3 hours.
ii) Remove the analyzer's protective cover.
iii) Locate the meter readout and attach leads from the
readout terminals to the chart recorder. Deactivate the
automatic zero on auto zeroing models.
iv) Reinstall the protective cover.
v) Turn on the analyzer.
vi) Select a voltage range on the chart recorder so that full
scale of chart recorder equals full scale voltage of the
analyzer meter on the range under test.
vii) The chart recorder must indicate both negative and
positive zero drift. If necessary, offset the chart recorder
zero 5 units up scale.
viii) As soon as the warm-up lock-out feature deactivates,
zero and span the analyzer with the analytical gases per
manufacturer's operating instructions, and start the chart
recorder at a minimum chart speed of 0.5 inches per minute.
ix) Do not adjust the analyzer or recorder controls (zero or
span) for the remainder of the test.
x) Reintroduce zero gas (if not done already) and start the
test.
xi) Mark the chart paper indicating the zero response, the
span response, and the start of the test.
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83 TP:E.4.
xil) Flow zero gas through the analyzer for one hour. (30
minutes for automatic rezeroing units.)
xiii) Introduce the span gas to the analyzer (do not adjust
the equipment).
xiv) Reintroduce the zero gas to the analyzer (do not adjust
the equipment) .
xv) Reintroduce the span gas to the analyzer (do not adjust
the analyzer).
xvi) Flow span gas through the analyzer for one hour.
xvii) Reintroduce zero gas to the analyzer.
c) Calculations
i) Compute the difference (as a percent of full scale chart
deflection) between the analyzer zero response for the first
span check (step b)viii)) and the zero response after the 1
hour span check (step b) xiv)) (zero drift).
ii) Locate on the chart the maximum and minimum analyzer zero
response during the first 1 hour period (step b) xii)).
iii) Compute the difference (as a percentage of full scale
chart deflection) between the analyzer zero-response for the
first span check (step b) viii)), and the maximum zero re-
sponse and then the minimum zero-response as identified in
step c) ii) (zero drift).
iv) Compute the analyzer span-response at the 1 hour span
check as the difference between the chart reading of the span
gas (step b) xiii) and the chart reading of the zero gas
(step b) xiv)) (span response).
v) Locate on the chart the maximum and minimum chart reading
during the one hour span period (step b) xvi)).
vi) Compute the difference (as a percentage of full scale
chart deflection) between the analyzer zero-response immedi-
ately prior to the one hour span period (step b) xiv)), and
the maximum and minimum span chart readings identified in
step c) v) (span response).
vii) Compute the difference (as a percentage of full scale
chart deflection) between the span chart deflection at the
end of the 1 hour span, and the zero-response after the 1
hour span (span response).
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84 TP:E.4.
viii) Compute the difference (as a percentage of full scale
chart deflection) between the span chart deflection immedi-
ately prior to the start of the one hour zero test (step b)
viii)) and the zero-response just prior to that span check
(span response).
ix) Compute the difference (as a percent of full scale chart
deflection) between the zero-response just prior to the start
of the 1 hour span (step b) xiv)), and the zero-response just
after the 1 hour span (step b) xvii)) (zero drift).
x) Compute difference (as a percentage of full scale chart
deflection) between the following span responses in step c):
(vi max) to (iv) span drift
(vi min) to (iv) span drift
(vii) to (iv) span drift
(viii) to (iv) span drift
d) Acceptance Criteria
i) If each value computed in steps i), iii) max, iii) min,
and ix) is less than or equal to the specifications listed
for zero drift, the zero drift of the analyzer is acceptable.
(Reference value: ±2% fs L.S.)
ii) If each value computed in step x) is less than ojr equal
to the specifications for span drift, the span drift of the
analyzer is acceptable. (Reference value: ±2% fs L.S.).
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85 TP: E. 5. -6.
5. Analyzer Span Drift Test Procedure
(See Analyzer Zero and Span Drift Test Procedure, E.4.)
6. Analyzer Noise Test Procedure
(See Analyzer Gaseous Interference and Noise Test Procedure, E.8.)
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86 TP:E.7.
7. Analyzer Sample Cell Temperature Test Procedure
(See Test Procedure Section H.I.a), Warm-up Lock-out Test Procedure),
a) Equipment Required
i) Candidate instrument.
ii) Thermocouple readout device.
iii) Type J or type T thermocouple.
b) Test Considerations
i) The sample cell test procedure may be run concurrently
with the zero/span drift test or any other test that begins
with an analyzer that is not warmed up.
ii) It is recommended that the test equipment remain hooked
up to the analyzer for the duration of the analyzer check
out, and the temperature of the sample cell should be moni-
tored from time to time.
c) Test Sequence
i) Locate on the sample cell a point, based on engineering
judgement, that would be the coldest point.
ii) Attach a thermocouple to the sample cell at the location
identified in step i).
iii) Conductive, convective, and radiation losses must be
considered in the selection of the location, and in the
manner of thermocouple attachment.
iv) Stabilize the analyzer at the prevailing ambient temper-
ature for at least 3 hours.
v) Record the sample cell temperature.
vi) Turn on the analyzer.
vii) As soon as the warm-up lock out feature is deactivated,
record the temperature of the sample cell.
viii) Immediately switch to sample ambient air (or analytical
gas at the ambient temperature) through the sample line.
ix) Monitor the sample cell temperature over the next 5
minutes.
x) Record the lowest sample cell temperature during the 5
minute period.
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87 TP:E.7.
d) Calculations
(None)
e) Acceptance Criteria
i) If the temperature recorded in step c) v) is approximately
the same as the ambient temperature, the analyzer is properly
stabilized.
ii) If the temperatures recorded in step c) vii) and step c)
x.) are equal to or greater than the specifications for sample
cell temperature, the sample cell temperature is acceptable.
(Reference value: 49°C (120.2°F).)
iii) While monitoring the sample cell temperature during the
analyzer check-out procedure, if the temperature is less than
the specifications when concentration data (span or sample)
is read, the acceptance in step ii) is void. (Reference
value: 49°C (120.2°F).)
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88 TP:E.8.
8. Analyzer Gaseous Interference and Noise Test Procedure
a) Equipment Required
i) Candidate instrument.
ii) One high impedence (1 megohm or greater) digital volt-
meter with at least 4% digit resolution. Generally, a 2 volt
(1.9999 v) and a 20 volt (19.999 v) scale will be adequate.
A chart recorder of similar impedence, resolution, and
scaling may be used in place of a voltmeter.
iii) One calibration gas with approximately 14% C02 and the
balance N?.
iv) One steam generator.
v) One mixing chamber with probe attachment, dilution valve,
and chamber air temperature readout system.
vi) One calibration gas with approximately 100 ppm NO . The
N0_ value must have been checked within 48 hours of the start
of the testing sequence with a chemiluminescent analyzer
meeting the specifications of 40 CFR 86 Subpart B, D, or N.
vii) One span gas between 70 and 90 percent of full scale on
the low range, and bottled zero gas.
viii) Tedlar sample bags.
ix) Associated lines and fittings (non-reactive).
b) Test Sequence
i) Remove the analyzer's protective cover.
ii) Locate the meter readout and attach the voltmeter or
chart recorder leads to the meter terminals.
iii) Reinstall the analyzer's protective cover.
iv) Temporarily bypass the water trap.
v) Warm up the analyzer.
vi) Introduce the span gas to the analyzer through the span
port.
vii) Adjust the span so that the analyzer reads 100 percent
of low scale.
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89
TP:E.8.
viii) Observe the voltmeter reading at 100 percent full scale
of the analyzer and record the voltage value. Alternatively,
adjust the chart recorder so that full scale is equivalent to
the analyzer full scale.
ix) Zero and span the analyzer with the analytical gases to
the proper values.
x) Fill a sample bag with span gas.
xi) Introduce the span gas from the sample bag to the ana-
lyzer through the probe.
xii) After the reading has stabilized, observe the voltmeter
or chart recorder. Record the highest value and the lowest
value over a 3 minute time span. The scale can be changed
for better resolution.
xiii) Fill another sample bag with CO .
xiv) Introduce the C0? through the sample probe.
xv) Record the average voltmeter or chart recorder reading.
The scale can be changed for better resolution.
xvi) Fill a sample bag (after purging with N ) with NO^.
xvii) Introduce the N07 through the sample probe.
xviii) Record the average voltmeter or chart recorder read-
ing. The scale can be changed for better resolution.
xix) Start the steam generator.
xx) Attach the probe to the mixing chamber and adjust the
dilution valve to obtain a 40°C (101°F) temperature in the
dilution box. To prevent condensation in the analysis system
this test should be performed with an ambient temperature
between 30°C and 40°C. This test cannot be performed cor-
rectly when testing at the lower ambient temperature condi-
tions specified in Section G of this chapter, and should
therefore, be omitted when testing under Section G.
xxi) Sample from the dilution box.
xxii) Record the average voltmeter or chart recorder reading.
The scale can be changed for better resolution.
xxiii) Reconnect the water trap.
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90 TP:E.8.
xxiv) Repeat steps xix) through xxii) with an ambient temp-
erature at the same value as in step xx) and 40 °C in the
dilution box. When repeating this test at the operating
environmental conditions specified in Section G of this
chapter, perform this test with a 40°C dilution box tempera-
ture and the analysis system at the prevailing ambient temp-
erature.
c) Calculations
±) Compute the difference between the high and low reading
recorded in step b) xii) , then divide that result by the full
scale voltage value recorded in step b) vii). This value,
expressed as a percentage and divided by -2, is defined as
noise of the analyzer.
ii) Divide the value recorded in step b) xv) by the full
scale voltage value recorded in step b) vii). The result,
expressed as a percentage, is the CO interference of the
analyzer.
iii) Divide the value recorded in step b)xviii) by the full
scale voltage value recorded in step b)vii). The result,
expressed as a percentage, is the NO. interference of the
analyzer.
iv) Divide the value recorded in step b)xxii) by the full
scale voltage value recorded in step b)vii). The result,
expressed as a percentage, is the water interference of the
analyzer.
v) Divide the value recorded in step b)xxiv) by the full
scale voltage value recorded in step b)vii). The result,
expressed as a percentage, is the water interference of the
system.
d) Acceptance Criteria
i) If the percentages calculated in paragraph c) for the
analyzer are equal to or less than the specifications for
noise and gaseous interferences (Chapter V, Section E.), then
the noise and gaseous interferences are acceptable.
Reference values: noise = ±0.5%
CO = 1.5% fs L.S. HC; 1.0% fs L.S. CO
NO^ = 1.5% fs L.S. HC; 1.0% fs L.S. CO
H20 = 1.5% fs L.S. HC; 1.0% fs L.S. CO
ii) Inspect the analysis system between the water trap and
the optical bench for condensed water. If water vapor drop-
lets are found repeat the water checking test for a longer
period of time. If substantial water is found, the effec-
tiveness of the water trap is not acceptable.
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91 TP:E.9.
9. Analyzer Electrical Interference Test Procedure
a) Equipment Required
i) Candidate instrument.
ii) One high impedence (Imegohm or greater) digital volt
meter with at least 4^ digit resolution. Generally, a 2 volt
(1.9999 v) and a 20 volt (19.999 v) scale will be adequate.
A chart recorder of similar impedence, resolution, and
scaling may be used in place of a voltmeter.
iii) One vehicle with high energy ignition system, and solid
core ignition and coil wires.
iv) One 3 amp or more variable speed (commutator type) hand
drill with a plastic handle.
v) One 20 foot extension cord with 3 sixteen gauge wires, and
a 2 plug outlet. For systems without ground fault circuits,
a 2 wire extention cord or a non-grounded adaptor will be
required.
vi) A CB transmitter at or near FCC legal maximum power with
a matching antenna.
vii) One variable voltage transformer (90v to 130vAC).
viii) One span gas between 70 and 90 percent of full scale on
the low range.
ix) One dry flannel cloth.
b) Test Sequence
i) Remove the analyzer's protective cover.
ii) Locate the meter readout, and attach the voltmeter or
chart recorder leads to the meter terminals.
iii) Reinstall the analyzer's protective cover.
iv) Check the outlet box to be used for proper hot lead/
neutral lead orientation and for proper ground.
v) Plug the analyzer's power cord into a 2-outlet grounded
electrical outlet box and warm up the analyzer.
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92 TP:E.9.
vi) Reserved
vii) Reserved
viii) Introduce the span gas through the span port, and
adjust the span so that the analyzer reads 100 percent of low
scale. It is not necessary to substitute the electrical span
in pressure and temperature compensated models for this gas
span.
ix) Observe the voltmeter or chart recorder reading at 100
percent full scale of the analyzer, and record the voltage
value.
x) Zero and span the analyzer with the analytical gases to
the proper values. Record the values. It is not necessary
to substitute the electrical span in compensated models for
this gas span.
xi) Introduce span gas to the analyzer. Record the average
span gas voltage levels over a 5 minute time span. The scale
can be changed for better resolution.
xii) Either move the analyzer or the vehicle (engine compart-
ment) to within 2 feet of each other.
xiii) Introduce the span gas to the analyzer.
xiv) Open the hood and start the vehicle.
xv) Record the average span gas voltage level during a 5
minute time span.
xvi) Stop the vehicle engine.
xvii) Plug the electric drill into the other outlet of the
same receptacle that the analyzer is connected to.
xviii) Move the drill at approximately 3 to 4 feet high to
within 12 inches of the analyzer. At four locations around
the analyzer vary the drill speed from minimum to maximum
speed. Attempt to locate the positions that provide the
greatest interference.
xix) Record the average span gas voltage level at each posi-
tion.
xx) Key the CB radio within 50 feet of the analyzer.
xxi) Record the average span gas voltage level when the CB
radio is transmitting.
xxi) Turn the analyzer off.
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TP:E.9.
xxiii) Plug the extension cord into the variable voltage
transformer and set the transformer output to 110 volts.
xxiv) Turn the analyzer on, and warm it up.
xxv) Check the zero and span. If necessary reset to the
exact voltage level recorded in step b) x). It is not neces-
sary to substitute the electrical span in compensated models
for this gas span.
xxvi) Repeat step b) xii) through xxi).
xxvii) Record the average span gas voltage level as indicated
in steps b) xv) , xix), and xxi).
xxviii) Reduce the transformer output voltage to 90 volts.
Let analyzer stabilize for 2 minutes.
xxix) Repeat steps b) viii) through xxi) with the extention
cord and 90 volt set-up. Non-relevant set-up steps may be
omitted.
xxx) Increase the transformer output to 130 volts. Let the
analyzer stabilize for 2 minutes.
xxxi) Repeat steps b) viii) through xxi) with the extension
cord and 130 volt set-up. Non-relevant set-up steps may be
omitted.
xxxii) If the unit has an analog meter, observe and record
the meter reading with span gas.
xxxiii) Rub the meter face 10 times with the dry flannel
cloth in the up-scale direction. Record the meter reading.
(Only required at lowest and dryest temperature used during
evaluation testing).
c) Calculations
i) Compute the difference between each set of voltage levels
recorded in step b) x) and b) xv). The maximum difference
expressed as a percentage of the voltage recorded in step b)
ix) is defined as the RF interference (RFI).
ii) Compute the difference between each set of voltage levels
recorded in step b) x) and b) xx). The maximum difference
expressed as a percentage of the voltage recorded in step
b)ix) is defined as the induction interference.
iii) Compute the difference between each set of voltage
levels recorded in step b)x) and b)xxi). The maximum differ-
ence expressed as a percentage of the voltage recorded in
step b)ix) is defined as the VHF interference.
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94 TP:E.9.
iv) Compute the difference between the voltage levels re-
corded in step b) x) and step b) xxvii). The largest result
expressed as a percentage of the voltage recorded in step b)
ix) is defined as the line interference.
v) Compute the difference between the voltage levels recorded
in step b) x) and b) xxix). Compute the difference between
the voltage levels recorded in step b) x) and b) xxxi). The
largest value of the results expressed as a percentage of the
voltage recorded in step b) ix) is defined as the line vol-
tage interference.
vi) Compute the difference between the meter reading recorded
in step b) xxxii) and b) xxxiii). Also compute the differ-
ence as a percentage of full scale. The difference is de-
fined as the static electricity interference.
d) Acceptance Criterion
i) If the percentages calculated in paragraph c) are equal to
or less than the electronic interference specifications
(Chapter VII, Section E.), then the electrical interferences
are acceptable.
Reference values: RFI = 1.0% fs L.S.
VHF = 1.0% fs L.S.
Induction = 1.0% fs L.S.
Line = 1.0% fs L.S.
Line Voltage = 1.0% fs L.S.
Static = 1 meter division or 2% fs L.S.
whichever is greatest.
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95 TP:E.10.
Propane to Hexane Conversion Factor Test Procedure
a) Testing Concepts
i) The conversion factor shall be evaluated at two hexane
concentration levels.
1) 250 ppmh ( _+ 15 ppmh) on the low scale, and
2) 1500 ppmh ( +_ 150 ppmh) on the high scale.
ii) A minimum of three samples of the hexane gas at each
concentration level shall be performed.
iii) Because of the exceptional hang-up characteristics of
hexane, an auxilliary sample/spanning system that is
specially constructed to be essentially hang-up free may be
used. The auxilliary system should be of laboratory quality,
and may bypass the candidate analysis system controls.
iv) The test should always be conducted at an ambient temper-
ature greater than 20°C (68°F).
v) A flame ionization detector (FID) properly optimized and
calibrated (see 40 CFR 86 Subpart D or N) may be used to
provide additional quality control on the conversion factor
determination procedure.
b) Test Sequence
i) Set up the test equipment.
ii) Warm-up the candidate analyzer.
iii) Leak check the system used.
iv) Span the analyzer on the low range with a propane cali-
bration gas near ( +_ 5%) the expected low concentration
hexane response, and with bottled zero gas. Use the propane
to hexane conversion factor indicated on the analyzer.
v) Alternately cycle low concentration hexane gas and the
calibration gas through the analyzer a total of 3 or more
times.
vi) Record each response for each gas.
vii) Span the analyzer on the high range with a propane
calibration gas near ( _+ 5%) the expected high concentration
response, and bottled zero gas. Use the propane to hexane
conversion factor indicated on the analyzer.
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TP:E.10
viii) Alternately cycle the high concentration hexane gas and
the calibration gas through the analyzer a total of three or
more times.
ix) Record each response for each gas.
c) Calculations
i) For the values recorded in step b) vi), and b) ix), com-
pute the mean (x) and standard deviation(s) for the hexane
response and the propane response.
ii) Use an of 0.05 and the student's "t" test to determine
the confidence Interval of the population mean' at the 90%
confidence level based on the values computed in step c) i)
for each range.
iii) Use the following equation to determine the mean propane
to hexane conversion factor (CF) for each range:
(.5) + (-5)(x, - Hex Cal)
CF = _
Hex Cal
where:
x hex = the mean hexane response determined in step c) i).
Hex Cal = concentration of hexane calibration gas.
iv) Determine if sufficient number of cycles (steps b) v) and
b) viii)) were run on each range by the following equation:
(.5)(x - x._) + (.5) Hex Cal
0.01 1 hex CI "
Hex Cal
where:
x hex = the mean hexane response determined in step c) i).
x_ = the confidence interval determined in step c) ii).
\j J.
Hex Cal = concentration of hexane calibration gas.
v) For each range, multiply the mean propane response (x)
determined in step c) i) by the CF computed in step c) iii).
vi) Determine the difference between the CFs for each range,
and determine the mean CF.
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TP:E.10
d) Acceptance Criteria
±) If the value computed in step c) iv) is greater than 0.01,
perform additional cycles (see steps b) v) and b) viii))
until the computed value is less than 0.01.
ii) If the difference between the CFs computed for each range
(step c) vi) ) is greater than .030 a sperate CF must be used
for each range. If the difference is less than .030, a mean
CF may be used for both ranges.
iii) The CF value(s) determined by step d) iii) must agree
exactly with the CF posted on the analyzer. ASTM round-off
shall be used.
iv) The mean propane value determined in step c) v) must
agree with the propane calibration gas within 1 percent of
the propane calibration gas concentration.
v) The final CF value must be between the limits identified
in Chapter VII, Section E, paragraph 9.
(Reference value: 0.48 1 CF 1 .56)
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98
TP:F.l.
F. Sample System Test Procedures
1. Sample Cell Pressure Variation, Low Flow, and Response Time
a) Test Equipment
i) Candidate instrument system.
ii) One span gas cylinder with a concentration between 70 and
90 percent of full scale, and bottled zero gas.
iii) One gauge (0-30 inches of water).
iv) One pinch clamp.
v) One Tedlar sample bag (approximately 3 cubic foot capacity),
vi) One 3-way ball valve, minimum orifice size is .180 inches.
vii) One stop watch or timer.
ix) Associated fittings and lines (non-reactive material).
b) Testing Sequence
This test procedure is written around parallel EC and CO analyzers,
and should be performed on each analyzer. If the analyzers are in
a series configuration then an additional pressure gauge will be
required, but the test can be performed on both analyzers at the
same time. A special test set-up that attaches to the probe and
provides gas at approximately the same pressure as occurs during
sampling may be substituted for the Tedlar bag, ball valve, and
timer. Using a solenoid valve interfaced with a timer or chart
recorder will provide more accurate results.
i) Identify the sample line entering the sample cell.
ii) Install a tee fitting In the sample line Immediately
upstream of the sample cell (in as close as practical).
Install the tee with the branch pointing up.
iii) Connect the gauge to the tee with the suitable length of
flexible tubing.
iv) Warm up the analyzer.
v) Zero the analyzer.
vi) Introduce span gas through the spanning network. Record
the pressure gauge reading, and the span response.
vii) Recheck the zero. If the zero has shifted repeat steps
v), vi), and vii).
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TP- V
99 ir.r.
viii) Switch the analyzer from span gas flow to sample flow
(pump on) .
ix) Record the maximum and minimum fluctuations in the gauge
reading.
x) Attach the pinch clamp to the pressure gauge line. Slowly
pinch the line until the gauge fluctuations are minimized.
xi) The gauge reading should be approximately halfway between
the readings recorded in step ix) . Record the stabilized
gauge reading in step x) .
xii) Attach the common port of the 3-way valve to the probe
with a leak free adapter.
xiii) Attach a short length of tube to one of the remaining
two ports of the three-way valve, and sample room air through
the tube.
xiv) Fill the sample bag with span gas.
xv.) Attach the sample bag to the remaining port of the 3-way
valve .
xvi) The 3-way valve should be sampling room air.
xvii) switch the 3-way valve to the sample bag, compare the
stabilized concentration reading of the bag to the reading in
step vi) . A difference of more than 1 percent from the con-
centration reading in step vi) could indicate a leak in the
system. Repair any leaks, and restart the procedure at step
xviii) Recheck the zero by switching the 3 way valve back to
room air.
xix) Identify the concentration value corresponding to 95% of
the span gas in the bag. Record the 95% value.
xx) Switch the 3-way valve to the sample bag and simultane-
ously start a timer.
xxi) When the analyzer response reaches the 95% value stop
the timer. Record the elapsed time.
xxii) Record the sample cell pressure after the analyzer
reading has stabilized. Record the stabilized analyzer
concentration reading.
xxiii) Identify the concentration value (5%) corresponding to
the stabilized reading in step xxii) (100%) minus the 95%
value identified in step xix) .
-------
100 TPrF.l.
xxiv) switch the 3-way value back to room air and simul-
taneously start the timer.
xxv) When the analyzer reaches the 5% value, stop the timer.
Record the elapsed time.
xxvi) Connect the needle valve between the probe and the
3-way valve.
xxvii) Adjust the needle valve until the low flow indicator
is just barely activated.
xxviii) Repeat steps xvi) through xxv).
xxix) Use the same 95% and 5% values identified in step xix)
and xxiii).
xxx) Record the 5% and 95% response times.
xxxi) Record the stabilized concentration reading, and sample
cell pressure in the same manner used in step xxii).
c) Calculations
i) Compute the difference in pressure between step vi) and
step xi) , and step vi) and step xxii). The values will be
the pressure difference between spanning and sampling.
ii) Compute the difference between maximum and minimum pres-
sure readings in step b) ix). The value will be the pressure
variation during sampling.
iii) Compute the difference in pressure between step xi) and
step b) xxxi). The value is the difference in pressure
variation between normal flow and low flow conditions.
iv) Compute the percentage change in analyzer gas response
between step b) xxii) and step b) xxxi).
d) Acceptance Criteria
(
i) If the calculated value in steps c)i, and c)iii are less
than 4 inches of water, and less then 6 inches of water for
step c)ii, the pressure variations in the analyzer flow
system under these test conditions are acceptable.
(
ii) If the change in analyzer response computed in step c)iv
is less than 1.5 percent and the elapsed times recorded in
step b) xxx) are less than 14 seconds, the low flow indicator
system is acceptable as well as the system response time.
iii) If the elapsed time in steps b) xxi) and b) xxv) is less
then 14 seconds, the system response time is acceptable under
normal conditions.
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TP« F
101 iP.t.
iv) It is recommended that the sample cell pressure gauge(s)
remain hooked up for the duration of the analyzer check out.
If the sample pressure varies by more then 4 inches of water
from the most recent span pressure, then the acceptance in
d)i is void.
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102
2. Maximum Sample Cell Pressure Variation during Sampling Test Procedure
(See Test Procedure F.I)
3. Maximum Sample Cell Pressure Variation Between Normal Flow
and Low Flow Indication Test Procedure
(See Test Procedure F.I)
4. Response Time Test Procedure
(See Test Procedure F.I)
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103 ".r.^.
5. System Leakage Test Procedures
a) Equipment Required
i) Candidate instrument.
ii) One tee fitting.
iii) One needle valve.
iv) One span gas 70 to 90 percent of full scale on the low
range, and bottled zero gas.
v) Associate lines and fittings (non-reactive).
b) Test Sequence
This sequence is written to evaluate the ease of operation of the
leak checking equipment. It may also be used to correlate abbre-
viated leak checks with the gas comparison test.
i) Install the tee fitting between the probe and the sample
line.
ii) Attach the needle valve to the remaining port of the tee
and close the valve.
iii) Warm up the analyzer.
iv) Zero and span the analyzer with the analytical gases. It
is not necessary to substitute the electrical span in compen-
sated models for this gas span.
v) Record the span value.
vi) Place the probe in the leak check receptacle.
vii) Record the analyzer response to span gas introduced
through the leak check recepticle, probe, and sample line.
viii) If the analyzer response in step vii) differs from the
response in step v) by more than 1 percent of the value
recorded in step v) , check the system for leaks or other
problems. Restart the procedure at step iii).
ix) Compute the concentration value that would result from a
leak of 3 percent.
x) Gradually open the needle valve until the computed concen-
tration valve is obtained.
xi) Use the bubble check method to check for leaks in the
spanning system.
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104
xii) If the unit is equipped with an abbreviated leak check
or leak warning light, perform the manufacturers leak check
with the calibrated leak from step x).
xiii) Repeat steps ix) through xi) with leaks of 1%, 2%, and
4%, if the unit is equipped with an abbreviated leak check.
c) Calculations
i) Plot the leak rate against the manufacturers abbreviated
leak check criteria (linear regression is acceptable).
d) Acceptance Criteria
i) If the spanning system "shows significant leaks at fit-
tings, attempt to repair the leaks by tightening or replacing
the fittings. If leaks occur in other locations of the
spanning system, or appear to be the result of system design,
an engineering report must be submitted by the analyzer
manufacturer describing the causes and preventive remedies
for the leak prior final acceptance of the system.
ii) The relation of leak rate to the abbreviated checking
criteria must be single valued, and of sufficient magnitude
that interpolation of the exact leak rate can be made with
little difficulty.
6. HC Hang-up Test Procedure
(See Test Procedure C.4.)
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105 ^r.u.i.
Operating Environmental Test Procedure
1. Test Procedure
a) Equipment required
i) Candidate instrument
ii) Environmental chamber with temperature capability between
35°F and 110°F, and humidity capability between 10 and 99
percent relative humidity.
b) Test Conditions
i) 105°F (+ 5%°F) with a relative humidity between 80 and 85
percent (non-condensing).
ii) 40°F (+ 5°F) with a relative humidity between 75 and 80
percent with a 10 mph wind.
iii) 35°F (+ 5°F) with a relative humidity between 10 and 20
percent.
c) Required Tests of each test condition (Test Procedure numbers
are given in parentheses).
i) System Warm-up (H.I.a))
ii) System Leakage (F.5.)
iii) Sample Line Crush Test (C.2.)
iv) Analyzer Calibration Curve (E.I.)
v) Pressure and Temperature Compensation (E.3. b) and c))
vi) Analyzer Zero and Span Drift (E.4.)
vii) Sample Cell Temperature (as applicable, see E.7. and H.I.)
viii) Analyzer Water Interference (E.8.)
ix) Sample Cell Pressure Variation, Low Flow, and Response
Time (F.I.)
x) HC hang-up (C.4)
xi) If used, all automatic systems (Chapter VIII)
xii) If used, anti-dilution system
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106 TP:G.i.
xiii) If used, loaded mode kit
xiv) If used, automatic data collection system
d) Test Sequence
i) The analyzer shall be turned off and allowed to stabilize
at least 3 hours at the test condition prior to beginning the
performance check.
ii) The warm-up test followed by the leak check test shall be
the first two tests performed at each test condition.
iii) The remaining tests may be performed in any convenient
order.
iv) An additional leak check shall be performed at the com-
pletion of the required tests for each test condition.
v) The first test condition shall be the 35°F condition
followed by the 40°F and the 105°F conditions.
e) Acceptance Criteria
i) If the analysis system passes all of the individual test
requirements as specified by each test in c) and d), then the
environmental operating characteristics of the system are
acceptable.
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107
H. Fail-Safe System(s)
1. Warm-up Lock-out Test Procedure
a) Equipment Required
i) Candidate analyzer.
ii) The equipment required to perform the Analyzer Sample
Cell Temperature Test Procedure (see Section E.7.), if the
unit uses a heated sample cell (not required on other units).
iii) The equipment required to Perform the Analyzer Zero Test
Procedure (see Section E.4.).
iv) A timer.
b) Test Sequence
i) Follow the basic measurement preparations indicated in
Test Procedures E.4. and E.7.
ii) After the analyzer has stabilized at the ambient condi-
tions as determined by Test Procedure E.7. Turn on the
analyzer power and simultaneously start a timer. (A chart
recorder may be used).
iii) The chart recorder must indicate both negative and
positive zero drift. If necessary, offset the chart recorder
zero 5 units up scale.
iv) As soon as the warm-up lock-out feature deactivates,
record the elapsed time from power on, the sample cell temp-
erature, and immediately zero and span the analyzer with
analytical gases per manufacturer's operating instructions.
Simultaneously, start the chart recorder (in already started,
mark the chart) at a minimum chart speed of 0.5 inches per
minute.
v) Immediately after spanning, begin sampling ambient air (or
analytical zero gas at the ambient temperature) through the
sample line.
vi) Monitor the zero drift and the sample cell temperature
for 5 minutes.
vii) Record the lowest sample cell temperature during the 5
minute period.
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108
c) Calculations
i) Locate on the chart the maximum and minimum analyzer
zero-response during the 5 minute period.
ii) Compute the difference (as a percentage of full scale
chart deflection) between the analyzer zero-response deter-
mined by the span check in step b) iv) and the maximum zero-
response, and then the minimum zero-response as identified in
step c) i) -
iii) Determine the largest difference in step c) ii) and
multiply it by 2 (zero drift).
d) Acceptance Criteria
i) If the temperature observed in step ii) 2) is approxi-
mately the same as the ambient temperature, the analyzer is
properly stabilized.
ii) If the temperatures recorded in step ii) 4) and step ii)
7) are equal to or greater than the specifications for sample
cell temperature, the sample cell temperature is acceptable.
(Reference value: 49°C (120.2°F)).
iii) While monitoring the sample cell temperature during the
analyzer check-out procedure, if the temperature is less than
the specifications when concentration data (span or sample)
is read, the acceptance in step ii) is void.
iv) If the zero drift, as calculated in step c) iii) is less
than the specifications for zero drift (Chapter VII, Section
E.), then the zero drift after warm up is acceptable. (Ref-
erence value: ±2% fs L.S.).
v) Acceptance of the above criteria constitutes acceptance of
the Warm-up Lock-out system.
vi) If the analyzer manufacturer indicates a typical lock-out
elapsed time to the ultimate user, then the manufacturer must
show that the elapsed time supplied to the user is truly
typical if the time recorded in step b) iv) is more than 30
percent longer than the time indicated to the user. The time
recorded in step b) iv) must be reported in the evaluation
report for each environmental condition.
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109 TP:H.2.
2. Analyzer Low Flow Test Procedure
i) See Test Procedure F.I., Sample Cell Pressure Variation, Low
Flow, and Response Time.
ii) Visual Observation of Features
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110 TP:I.l.
I. System Correlation Test Procedures
The correlation procedure is designed to evaluate the performance of the I/M
analyzers when sampling auto exhaust. The NDIR procedure is slightly dif-
ferent from the FID HC correlation procedure. However, it is expected the
data collection phase of each procedure can occur simultaneously. For
clarity they will be presented as separate procedures. Note: the FID proce-
dure is not required for accreditation.
1. NDIR Analyzer Correlation Test Procedure
a) Equipment Required
i) Candidate instrument.
ii) A raw exhaust CO analysis system meeting the requirements
of 40CFR 86, Subpart D, for gasoline-fueled engines.
iii) A laboratory grade NDIR HC analyzer substantially simi-
lar in quality to the laboratory CO analyzer, and operated
according to the requirements for general NDIR analysis of
gasoline-fueled engines contained in 40 CFR 86, Subpart D.
iv) A tailpipe extension that meets the probe location re-
quirements in 40CFR 86 Section 312-79 (c) (v).
v) Two test vehicles.
vi) Calibration gases for each range used on both the candi-
date analyzers and the reference analyzer. In this test
procedure, calibration gases will be used instead of span
gases to span both analysis systems. The calibration gases
should be between 70 and 90 percent of full scale on each
range used. Calibration gases for the Subpart D analysis
system shall meet or exceed the requirements specified In
Subpart D.
vii) Option: An adjustable dilution box and mixing chamber
may be used to obtain different exhaust concentration levels
from the vehicle. The dilution box and mixing chamber would
be installed between the tailpipe and the analysis system
probes.
viii) Option: A chassis dynamometer would be useful for
loading the vehicle to obtain different emission levels, but
is not required.
b) Test vehicles
i) One 1975 or later non-catalyst light-duty vehicle (LDV),
LOT, or HDG is acceptable.
ii) One 1978 or later oxidation catalyst equipped vehicle
with air injection.
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111
ill) All vehicles must be in good operating condition with
all emission control systems functional. A 1975 FTP type
test may be performed on the vehicle to verify functional
operation of the emission controls.
iv) Fuel use shall meet the most recent EPA MVEL specifica-
tions for certification test fuel.
c) Test Procedure Overview
The correlation procedure consists of testing the candidate ana-
lyzer at several points on each range. The range scale of the
candidate analyzer determines the approximate test points. The
exact test points are then determined by the concentration levels
observed by the reference system. The exact test points are then
replicated several times (minimum of 6) based on the reference
system response values. This replicate data is then analyzed to
determine correlation between the candidate system and the refer-
ence system.
d) Test Sequence
i) Select a test vehicle, and warm up that vehicle with at
least 30 minutes of hard load. (freeway operation, hard
accelerations, etc.
ii) Prepare the analysis systems for measurement (i.e. warm-
up, spanning etc.) operate the reference system according to
the provisions in Subpart D where applicable.
iii) Insert the probe of the candidate instrument into the
tailpipe approximately 16 inches.
iv) Operate the vehicle (or adjust the dilution box) to
obtain stable concentration readings at approximately 20, 50,
70 and 90 percent of full scale concentration value on the
low range of the candidate analyzer.
v) Select the lowest useable range on the Subpart D system
for each test point in d)iv) (see § 86.338).
vi) Sample for approximately 1 minute at each test point.
vii) Record the average emission value of the candidate
instrument and the average chart deflection from the refer-
ence system over the last 10 seconds for each test point.
The two readings recorded at each test point should be re-
corded over the same time frame, and are defined as a
"paired" data point.
viii) Select the high range of the candidate instrument.
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112 TPrl.l.
ix) Operate the vehicle (or adjust the dilution box) to
obtain stable readings at approximately 20, 50, 70, and 90
percent of full scale on the high range of the candidate
instrument. If the higher emission values require impracti-
cal vehicle operation, cease data generation and continue
with the test procedure. At least one vehicle should be able
to achieve the higher values.
x) For the attainable test points in the preceding step,
repeat step d)vii).
xi) The chart deflections recorded in steps d)vii) and d)x)
for the Subpart D system are now defined as "reference set
points" that will be used for the remainder of the correla-
tion test. When repeating the test sequence with the same
vehicle or a different vehicle, the vehicle or dilution box
should be adjusted to obtain, as close as possible, the exact
"reference" chart deflection. For the test points not at-
tainable in step d)ix), the chart deflection of the reference
system becomes the set point the first time a data pair is
recorded for that test point.
xii) Repeat steps d) iv) through d) x) at the set points de-
scribed in step d)xi). Record the emission values from the
candidate system, and the chart deflections from the refer-
ence system.
xiii) Ground or short two plug wires on V8 engines (opposite
sides of intake manifold), or one plug wire for 6 cylinder
and 4 cylinder engines.
xiv) Perform steps d)iv) through d)x) at the set points de-
scribed in step d)xi) a minimum of three times. Record the
emission values from the candidate system, and the chart
deflections from the reference system.
xv) Select the 2nd test vehicle, and repeat steps d)iv)
through d)xiv) at the set points described in step d)xi).
Record the emission values from the candidate system, and the
chart deflections from the reference system.
xvi) Repeat the procedure as necessary to obtain a minimum of
6 replicate responses at each test point.
e) Calculations
i) For the candidate system compute the mean (x) and standard
deviation(s) of the emission values for each test point.
ii) For the reference system convert each chart deflection to
a concentration value from the analyzer calibration curve.
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113 TPrl.l.
iii) For the reference system compute the mean (x) and stan-
dard deviation(s) concentration values for each test point.
iv) Compute the normalized precision difference (A P) for
each test point by:
A P = ((Ks/ x) candidate) - ((Ks/ x) reference)
where:
Sample Size £ Sample Size J(
5 3.5 10 2.5
6 3.1 11 2.46
7 2.9 12 2.40
8 2.7 13 2.36
9 2.6 14 2.31
v) For each range of the candidate analyzer perform a linear
regression on all of the paired data that were measured on
that range. Force the regression through zero. The refer-
ence system is the independent variable. Identify the
slope(m) of the regression line.
vi) For each range of the candidate analyzer compute the
ratio(R) of the analyzer mean concentrations for each test
point corrected for the slope(m) identified in the preceding
step by:
R = (x reference/x candidate)m
f) Acceptance Criteria
i) Identify the largest A P value. If the largest Ap value
is less than or equal to the specification for P, then the
in-use precision of the candidate system is acceptable.
(Reference value: A P £5%).
ii) If the slope (m) for each range of the candidate analyzer
is within the limits for slope, then the slope test results
are acceptable.
(Reference value: 0.95 £ R £1.10)
iii) Identify the minimum and the maximum ratio(R) of slope
corrected mean concentration values. If the minimum and
maximum ratios are within the range specified, then the mean
concentration ratio test results are acceptable.
(Reference value: 0.90 <_ R £1.10)
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114 TP:I.2.
2. FID Analyzer Correlation Test Procedure (Not required for accreditation)
a) Equipment required
i) Candidate instrument.
ii) An HC analysis system meeting the requirements of 40CFR86,
Subpart D for gasoline-fueled engines.
iii) A tailpipe extension that meets the probe location
requirements in 40CFR86 Section 312(c)(v).
iv) Three test vehicles.
v) Calibration gases for each range used by both the candi-
date analyzers and the reference analyzer. In this test
procedure, calibration gases will be used instead of span
gases to span both analysis systems. The gases should be
between 60 and 90 percent of full scale on each range used.
vi) Calibration gases for the Subpart D analysis system shall
meet or exceed the requirements specified in Subpart D.
vii) Option: A dilution system that allows the auto exhaust
to be diluted in a controlled manner with a suitable mixing
chamber, may be used to obtain different exhaust concentra-
tion levels from the vehicle.
viii) Option: A chassis dynamometer may be used with or
without the dilution system to obtain different concentration
levels.
b) Test Vehicles
i) The type of test vehicle required for the FID correlation
test are the same as the type required for the NDIR correla-
tion. Generally it is preferred that the same vehicles be
used for both correlations.
c) Test Procedure Overview
The correlation procedure consists of testing the candidate ana-
lyzer at several points on each range. The range scale of the
candidate analyzer determines the approximate test points. The
exact test points are then determined by the concentration levels
observed by the reference system. The exact test points are then
replicated several times (minimum of 6) based on the reference
system response values. This replicate data is then analyzed to
determine correlation between the candidate system and the refer-
ence system.
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115 TP:I.2.
d) Test Sequence
The test sequence is identical to CO correlation test required
with the following exception.
i) Stabilized concentration readings of approximately 10, 20,
35, 50, 70, and 90 percent of full scale concentration values
should be substituted for the value in step l.d)iv) and
l.d)ix). Record the HC concentration value from the candi-
date analyzer as ppmh or ppmC6.
e) Calculations
i) For the candidate system compute the mean (x) and standard
deviation(s) of the emission values for each test point.
ii) For the reference system convert each chart deflection to
a concentration value in ppm C3 (propane) from the analyzer
calibration curve.
iii) For the reference system compute the mean (x)- and stan-
dard deviation(s) concentration values for each test point.
iv) Compute the normalized precision difference ( ^ P) for
each test point by:
A P = ((Ks/ x) candidate) - ((Ks/ x) reference FID)
where:
Sample Size _K Sample Size K.
5 3.5 10 2.5
6 3.1 11 2.46
7 2.9 12 2.40
8 2.7 13 2.36
9 2.6 14 2.31
v) For each range of the candidate analyzer perofrm a linear
regression on all of the paired data that were measured on
that range. Force the regression through zero. The refer-
ence system is the independent variable. Identify the
slope(m) of the regression line.
vi) For each range of the candidate analyzer compute the
ratio(R) of the analyzer mean concentrations for each test
point corrected for the slope(m) identified in the preceeding
step by:
R = (x reference FID/x candidate)m
f) Acceptance Criteria
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116
i) For HC analyzers the following FID comparison should be
available:
1) Precision
2) Slope Comparison
3) Ratio of Modal Averages
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117 TP:J.l.-4.
J. Micro Processor Systems
In general, the evaluation of microprocessor systems will consist of oper-
ating each of the automatic features to insure that: a) each feature pro-
vides equivalent results as would be obtained by a manual system, and b)
each feature has the necessary controls to perform the required actions
conveniently and easily. Further guidance follows.
1. Automatic Zero/Span Check Test Procedure
a) The gas spanning feature must be used throughout the entire
evaluation procedure unless noted otherwise (e.g. pressure and
temperature compensation, Section E.3. b)).
b) The automatic span system shall be used with calibration gas
(instead of span gas) for the Calibration Curve Test Procedure
(E.I.).
c) Self-explanatory Test Procedures for the other requirements.
2. Automatic Leak-Check
a) If the system is equipped with an automatic leak-check feature,
utilize test procedure F.5. with the following changes.
i) In step b) x) of F.5. gradually open the needle valve
until the leak check fail light just comes on. Record the
observed concentration value.
ii) Then compare the calculated 3% leak concentration (step
b) ix) of F.5.) to the concentration value observed in a) i)
of this section.
b) Repeat the test three times.
c) Compute the standard deviation and mean of the observed concen-
tration (step a) i)).
d) The mean minus one standard deviation should be greater than
the calculated 3% leak concentration.
e) Check the interlock requirements.
3. Automatic Hang-up Check
a) Utilize test procedure F.6. to evaluate the automatic hang-up
feature.
b) Check the interlock requirements.
4. Automatic Read Feature
i) The automatic read feature shall be deactivated for all evalu-
ation testing except:
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118 TP:J.5.-9.
1) The response time portion of test procedure F.I. shall be
rerun with the automatic read feature operational.
2) All system correlation tests (Procedures in Section I)
shall be run with the automatic read feature operational.
3) Other tests self explanatory.
5. Dual Tailpipe
a) When evaluating the dual tailpipe feature, the difference
between the concentrations to be averaged shall be:
i) case 1: HC ^200 ppmh
CO >.!%
ii) case 2: 10 ppmh £HC£ 20 ppmh
.1% £CO<. .2%
b) A single tailpipe at the different concentrations may be used.
6. Automatic Test Sequence
a) Evaluate the automatic test sequence for proper function with
both single and dual tailpipe vehicles over both the pre-81 and
post-81 test procedures.
b) Utilize both the same and different cutpoints for the two mode
tests when evaluating the automatic test sequence feature.
7. Printer Feature
If the analysis system is equipped with a printer, the printer shall be
checked for proper operation. The printer shall provide the official
system results to be used in the correlation procedures (Section I).
8. Vehicle Diagnosis Feature
Check for proper operation. No other test procedures are required.
9. Anti-Tampering Feature
i) Visual observation
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