United States Office of Air Quality EPA Publication No. 340/1-89-003
Environmental Protection Planning and Standards June 1989
Agency Washington, DC 20460
Stationary Source Compliance Series
oEPA Field
Inspector's
Audit Techniques
Gas CEMS's
Which Accept
Calibration Gases
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340/1-89-003
Field Inspector's Audit Techniques
Gas CEMS's Which Accept
Calibration Gases
Prepared by:
Wayne E. Reynolds
CEM/Engineering Division
Entropy Environmentalists, Inc.
Research Triangle Park, North Carolina 27709
EPA Contract 68-02-4462
Work Assignment No. 36
EPA Project Officer Aaron Martin
EPA Work Assignment Manager:
Anthony P. Wayne
Prepared for:
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
Stationary Source Compliance Division
Office of Air Quality Planning and Standards
Washington, DC 20460
June 1989
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DISCLAIMER
This material has been funded wholly or in part by the United States
Environmental Protection Agency under Contract No 68-02-4462 to Entropy
Environmentalists, Inc. It has been subjected to the Agency's peer and
administrative review, and it has been approved for publication as an EPA
document. Mention of trade names or commercial products does not constitute
endorsement or recommendation for use.
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TABLE OF CONTENTS
1. Overview 1
2. Planning 2
2.1 Gather Information 2
2.2 Determine Number of Audit Gases Per Channel 2
2. 3 Select Audit Gases 2
2.4 Arrangements With Source 3
2.5 Legal Authority and Liability 4
3- General Principles of Audit Gas Injection 5
3.1 Audit Gas Injection for an Extractive CEMS 5
3.2 Audit Gas Injection for a Point In-Situ CEMS 5
4. Conducting the Field Audit 15
4.1 Audit Gas Injection 15
4 .2 Number of Gas Injections 15
4 . 3 Data Recordkeeping 16
5 . Post-Audit Activities 17
5-1 Plot CEMS Response as Function of Audit Gas Concentration.... 17
5.2 File Data 17
5 .3 Follow-Up Activities 17
5.4 No Correction of Reported Emissions Data 17
6. Data Forms 18
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1. OVERVIEW
This guideline* is for the use of control agency field inspectors in plan-
ning and conducting audits of continuous emission monitoring systems (GEMS's)
for gaseous pollutants. The document includes:
• An outline-of planning activities;
• An outline of principles for audit gas injection;
• Procedures for conducting a field audit;
• A discussion of post-audit, activities; and
• Example data forms.
The audit procedures in this report:
• Are only applicable to gas GEMS's configured to accept cylinder gas
injections; and
• Assume the availability of a source technician to assist with the
audits as directed by the control agency field inspector.
• May be used to conduct cylinder gas audits (CGA's) of 40 CFR 60,
Appendix F, Procedure 1, provided:
(1) audit gases are selected according to Appendix F criteria, and
(2) each gas is injected into the GEMS three times rather than two.
* Prepared under EPA Contract No. 68-02-4462, Task No. 36, by Entropy Environ-
mentalists, Inc., Research Triangle Park, North Carolina.
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2. PLANNING
Preparation for the audit should begin well in advance of the target audit
date. If all audit gases are not on hand, a gas vendor will need at least 30
days lead time to prepare, analyze, and ship the gases. A Pre-Audit Data Form
is provided in Section 6. Much of the necessary information will be on file at
the Agency; the remainder can be obtained from the source contact. Major steps
in the pre-audit preparation process are discussed below.
2.1 GATHER INFORMATION
Information that will be needed in the audit gas selection process
includes:
1. the range of each gas measurement channel;
2. the typical concentration level of the effluent; and
3- effluent concentrations at the level of the applicable emissions
standards.
Information regarding gas measurement ranges should be contained in the
Performance Specification Test (PST) report on file at the agency. Information
regarding typical effluent levels can usually be obtained from both the
relative accuracy data in the PST report and the emissions reports or excess
emissions reports on file at the agency. Pollutant concentrations at the level
of the standard can be calculated from the emissions limits and typical diluent
concentrations.
2.2 DETERMINE NUMBER OF AUDIT GASES PER CHANNEL
The goal of a CEMS audit is to determine whether the emissions data
reported to the agency are of acceptable quality. This goal can be accom-
plished with one audit gas per measurement channel. Each additional audit gas
provides valuable information regarding CEMS performance, but increases the
overall cost of the audit. Two gases per channel are recommended for the
audits discussed in this document.
2.3 SELECT AUDIT GASES
There are two points in the measurement range of a CEMS that are of primary
concern: (1) the average effluent emissions level; and (2) the level of the
standard. When the audit is conducted with a single audit gas for each
channel, the concentration of this gas should approximate one of these levels.
2
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When the audit is conducted with two gases per channel, these gases should
bracket the effluent and emissions standard levels. Other acceptable criteria
for audit gas values are as specified in Appendix F for Cylinder Gas Audits
(CGA's). These criteria are:
Pollutants: 20-30% and 50-60% of span
02: 4-6% and 8-12% 02
C02: 5-8% and 10-14% C02
Each audit gas in the agency inventory should be listed on the "Inspector's
Quick Check Audit Gas Data Sheet"; an example data sheet is included in Section
6. Each gas should be given a label (e.g., "S02 #1," S02 #2,"- N0x #1," etc.)
for easy gas identification. The gas label and its certified concentration
should be recorded in the appropriate columns. This data sheet can be taken
into the field by the inspector. Accuracy acceptability can be determined at a
glance by comparing the audit results to the error band on the gas data sheet.
Some or all of the audit gases should be designated as "blind" gases, and
their exact concentrations should not be revealed to the source. The use of
blind audit gases precludes the possibility of CEMS response data being
intentionally biased to enhance apparent CEMS accuracy.
2.4 ARRANGEMENTS WITH SOURCE
Unless the audit is intended to be "unannounced," the following
arrangements should be made with the source:
1. Audit Date
Check with the plant environmental coordinator to ensure that the
target audit date does not conflict with the plant's projected
operating schedule. Avoid scheduling audits during times when sourc'e
maintenance outages are planned. A source need not be operating for
its CEMS to be audited, but technicians are generally in short supply
during outages, and major CEMS maintenance is often scheduled to
coincide with the unit outage. Point in-situ CEMS's employ temperature
compensation circuitry which is normally optimized for the generally
encountered range of effluent temperatures. Stack temperatures during
an outage are far outside these ranges.
2. Audit Logistics
Determine the location of and access to important CEMS components,
whether gas cylinders can be conveniently transported to the sampling
location, and if necessary, the length of audit gas transport line
needed to carry the audit gases to the sampling location.
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3- Availability of a GEMS Technician
A CEMS technician should be available to assist with the audit. He
will assist with:
• Determining data acquisition system (DAS) capabilities and
limitations;
• Locating key CEMS components (sample points, analyzer enclosures,
DAS displays);
• Identification of CEMS operating cycles;
• Physical contact with the CEMS hardware, such as connection of the
audit gas system; and
• Data retrieval at the completion of the audit.
Unannounced audits should not be attempted until the auditor and source
personnel are familiar with the necessary audit activities.
2.5 LEGAL AUTHORITY AND LIABILITY
Before going to the site, list the legal authority under which the audit
will be conducted and summarize the relevant regulations or permit conditions.
To minimize any liability for damage to the equipment, the auditor should
not have any physical contact with the CEMS hardware. Connecting the audit gas
system, or other physical contact with the installed equipment, should be done
by the CEMS Technician. As a general rule, the auditor should not adjust the
installed equipment or direct the CEMS Technician to make any adjustments or
changes. The purpose of the audit is to define the condition of the CEMS at a
specific time. Changes which may result from the audit are the responsibility
of the source owner.
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3. GENERAL PRINCIPLES OF AUDIT GAS INJECTION
To evaluate the entire sampling system, audit gas needs to be injected as
close to the sampling nozzle as possible. Injection procedures depend on the
type of CEMS (i.e., extractive or in-situ). The agency field inspector should
review the gas injection system with the source technician for the CEMS being
evaluated.
3-1 AUDIT GAS INJECTION FOR AN EXTRACTIVE CEMS
Extractive sampling systems may be configured in a variety of ways.
Regardless of the configuration, it is important that the sample stream
pressure and flow rate to the analyzers are the same during audit gas analysis
as during normal effluent sampling. This is accomplished by supplying an
excess of audit gas to the probe at atmospheric pressure while the CEMS
operates in its normal sampling mode; the CEMS withdraws audit gas at its
normal sample flow rate while excess audit gas is vented to the atmosphere.
Two general audit techniques are described in Subsections 3-1-1 and 3-1.2.
Subsection 3-1-1 is intended for those CEMS's which automatically vent excess
calibration gas through the probe into the stack. Subsection 3-1-2 covers
those CEMS's which require an external atmospheric vent to ensure that that
audit gas is supplied at atmospheric pressure.
The audit gas manifold shown in Figures 1 through 4 is optional. An audit
gas manifold is recommended, especially when several audit gases are required.
Most extractive systems incorporate a spare sample line, a calibration gas
transport line, or both in the sample line bundle between the probe valve box
and the analyzer enclosure. For convenience, one of these lines may be used to
transport audit gases from the analyzer location to the probe location. If the
calibration gas transport line is used for this purpose, it should be
disconnected from the calibration valves at the analyzer location so the CEMS
does not have to be in the calibration mode for the audit gases to flow to the
probe location.
3.1.1 Probe Vent Audit Technique
This technique is applicable to extractive sampling systems which vent
excess calibration gas through the probe to the stack. Examples are systems
which introduce calibration gas into a Tee or a filter chamber at the probe
exit (Figure 1) and in-stack dilution probe systems (Figure 2). These figures
5
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CHECK
VALVE
CALIBRATION GAS
TRANSPORT LINE .
^ -X
HEATED SAMPLE LINE
TO VALVE BOX OR
ANALYZER CABINET
STACK
OR
DUCT
PROBE
rrrtrrrrr ^^*
'-' —">-^^^
SAMPLE
IN
CHECK
VALVE
AUDIT GAS
TRANSPORT LINE
HEATED SAMPLE LINE
TO VALVE BOX OR
ANALYZER CABINET
SYSTEM CONFIGURATION
FOR NORMAL SAMPLING
EXCESS
AUDIT
GAS
PROBE
STACK
OR
DUCT
SYSTEM CONFIGURATION
FOR SAMPLING AUDIT GAS
AUDIT GASES
Figure 1. Extractive probe with calibration gas line into filter chamber on probe outlet.
3780 5/89
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y -- h-
OALIBRATION GAS ^ - V"^^ **"
/ /^ ^r^
VACUUM -^ — ^ //
r->il I i-rr-i-> ^> « • mi r- -^ / /
nit IITIOM Ain te '
^j
SYSTEM CONFIGURATION
FOR NORMAL SAMPLING
STACK
OR
Dlir.T
DILUTION
PROBE
•^
^
\
SAMPLE
IN
m
H3
5
r
D
r«
U
f«
\>
-c
/
Xli
x3-
X^
xi_
i
AUDIT GAS . /...^,.:_:.^s3t_._[TTJ
-
/ \
/DILUTED
F
•^sr
DILUT
riXl
-M
-txj
-M
SYSTEM CONFIGURATION
FOR SAMPLING AUDIT GAS
EXCESS
AUDIT
GAS
f
^y
DILUTDN
PROBE
STACK
OR
DUCT
fY) CT) AUDIT GAS
•nSr
5
H
J
j&
MANIFOLD
AUDIT GASES
Figure 2. In-slack dilution probe type extractive system.
3780 5/89
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illustrate the normal sampling configuration and the audit gas injection setup
for these systems.
The audit gas flow rate must be higher than the CEMS sample stream flow
rate to prevent dilution of the audit gas. The CEMS technician should use the
following procedure to establish the correct flow rate.
1. Connect the audit gas system to the CEMS injection port as shown in
Figure 1 or 2.
2. Inject a zero gas. Slowly increase the regulator delivery pressure
until the flow meter indicates the rate recommended by the CEMS
vendor. (In the absence of vendor information, 1 1pm is generally
acceptable for in-stack dilution probe systems; for other extractive
systems, choose a flow rate (1-2 1pm higher than the indicated total
sample stream flow rate.) Allow sufficient time for the analyzer(s) to
achieve a stable response. Record the stabilized response(s).
3. Decrease the gas injection rate by 0-5 1pm. Allow the analyzer
responses to stabilize and record the responses. If the responses at
both flow rates are the same, use the manufacturer's recommended flow
rate; proceed to Step 6.
4. If the monitor's zero response is greater at the lower flow rate,
increase the flow rate in 0.5 1pm increments until the zero response
remains unchanged with further flow rate increases. This indicates
that the flow rate is high enough to prevent dilution of the audit gas
with effluent.
5- Inject all audit gases at a rate of 1 1pm higher than the minimum flow
rate determined in Step 4 to prevent audit gas dilution.
6. Record the gas flow rate used and the time allotted for injection of
each gas.
After completion of the audit, be sure the CEMS is returned to its original
configuration and that all fittings are properly tightened to prevent ambient
air from entering the sampling system during normal operation.
3-1.2 External Atmospheric Vent Audit Technique
This technique is applicable to extractive sampling systems which have no
provisions for venting excess calibration gas. Two such systems are shown in
Figures 3 and 4. These figures also illustrate the external atmospheric vent
audit gas setup. The rotameter can be monitored visually to verify excess
flow. Note that in the absence of excess flow, ambient air will enter the
sampling system through the flow meter and will dilute the gas.
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3-WAY
CALIBRATION
VALVE
CALIBRATION GAS
TRANSPORT LINE
HEATED SAMPLE LINE
TO VALVE BOX OR
ANALYZER LOCATION
SYSTEM CONFIGURATION
FOR NORMAL SAMPLING
STACK
OR
DUCT
PROBE
SAMPLE
IN
EXCESS
AUDIT
GAS
ROTAMETER
PROBE
AUDIT GAS
TRANSPORT LINE
HEATED SAMPLE LINE
TO VALVE BOX OR
ANALYZER LOCATION
STACK
OR
DUCT
SYSTEM CONFIGURATION
FOR SAMPLING AUDIT GAS
AUDIT GASES
Figure 3. Extractive probe with 3-way calibration valve on outlet.
3780 5/89
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J
o
HEATED SAMPLE LINE
TO VALVE BOX OR
ANALYZER LOCATION
SYSTEM CONFIGURATION
FOR NORMAL SAMPLING
STACK
OR
DUCT
PROBE
SAMPLE
IN
EXCESS
AUDIT
GAS
ROTAMETER
AUDIT GAS
TRANSPORT LINE
Xh
-04
HEATED SAMPLE LINE
TO VALVE BOX OR
ANALYZER LOCATION
rtX
-M
-M
STACK
OR
DUCT
PROBE
SYSTEM CONFIGURATION
FOR SAMPLING AUDIT GAS
AUDIT GAS
MANIFOLD
AUDIT GASES
Figure 4. Extractive probe without 3-way calibration valve.
3780 5/89
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The CEMS technician should use the following procedures to inject the audit
gases.
1. Connect the audit gas system to the CEMS sampling system as shown in
Figure 3 or 4.
2. Select each gas in turn and adjust the regulator delivery pressure to
provide an excess flow of 1 to 1.5 1pm. Allow each analyzer to
stabilize before recording its response to an audit gas. Record the
gas injection rate used and time allotted for each gas.
After completion of the audit, be sure the CEMS is returned to its original
configuration and that all fittings are properly tightened to prevent ambient
air from entering the system during normal operation.
3.2 AUDIT GAS INJECTION FOR A POINT IN-SITU CEMS
Figure 5 shows an audit gas injection set-up for a point in-situ CEMS. The
audit gas manifold is optional. The audit gas flows through the calibration
gas injection port, through a stainless steel tube within the probe, and into
the measurement cavity within the in-stack ceramic filter on the end of the
probe. The audit gas flow rate must be adjusted so that there is sufficient
flow to force effluent from the ceramic filter (see Figure 6).
Excessive flow can cause errors due to (1) compression of the audit gas
within the ceramic filter, or (2) inadequate time for audit gas to warm to
stack temperature while traversing the length of the probe. The proper gas
injection rate will depend on the condition of the in-stack filter. Since the
condition of the filter will vary with time, the proper flow rate must be
verified each time a system is audited. The CEMS technician should use the
following procedure to establish the correct flow rate:
1. Connect the audit gas .system to the CEMS injection port as shown in
Figure 5 and adjust the regulator delivery pressure to about 10 psig for
each of the calibration gases.
!. Inject a high range audit gas (use S02 for SO /
NO only for NO monitors). Slowly open the r]
,/NO and S0_ monitors; use
only for NO monitors). Slowly open the flow control valve until
the flow meter indicates the rate recommended by the manufacturer. (For
LSI SM810 analyzers, the recommended rate is 2 1pm.) Allow sufficient
time for the analyzer to achieve a stable response. Record the
stabilized response.
3. Increase the gas injection rate by 0.5 1pm. Allow the monitor response
to stabilize and record the concentration value indicated by the
monitor. If the monitor response at both flow rates is the same, use
the manufacturer's recommended flow rate; proceed to Step 6.
11
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OPTIONAL ON-STACK
FLOW CONTROL EQUIPMENT
3780 5/89
ROTAMETER
FLOW
! CONTROL
j VALVE
TEFLON
TUBING
GEMS
TRANSCEIVER
CALIBRATION
GAS INJECTION
PORT
AUDIT GAS MANIFOLD
STACK OR DUCT
AUDIT GASES
^^
Figure 5. Point in situ GEMS audit gas injection setup.
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tttttttt/x
f •.s.t'A j '"ft...,. --vy' . . -• j&fcfet;'-L-C^ > ' .''.'•Jx^i'TTTNw. »
CALIBRATION
GAS
EFFLUENT
3780 5/89
Figure 6. Point in situ calibration gas injection.
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k. If the monitor response is greater at the higher flow rate, inject the
same gas at 0.5 1pm below the recommended flow rate, allow the response
to stabilize, and record the results. If the response at this flow rate
is the same as at the recommended flow rate, inject the audit gases at a
rate of 0.25 1pm lower than the recommended flow rate; proceed to Step
6.
5- If the monitor response at the lower flow rate is lower than at the
recommended flow rate, inject a zero level gas at the recommended flow
rate and note the stabilized zero level response. (A small positive
offset may be observed; some monitors amplify positive noise and ignore
negative noise.) Decrease the gas injection rate in increments of 0.25
1pm until the stabilized zero response begins to rise. This indicates
that the gas injection rate is too low to prevent the diffusion of stack
gases into the measurement cavity. Inject all audit gases at a rate of
0.25 1pm greater than the fl'ow rate which exhibits the increased zero
response.
6. Record the flow rate used and the time allowed for injection of each
gas.
After completion of the audit, be certain the gas injection port is sealed
tightly to prevent ambient air from entering the system during normal sampling.
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4. CONDUCTING THE FIELD AUDIT
A "General Audit Information" data form is provided in Section 6. On this
form record general audit information regarding plant contacts, audit
participants (agency and source), how data are collected, factors which may
affect data manipulation or audit results, problems noted, etc. Additional
notes and comments should be attached to this sheet if necessary.
The actual field audit is conducted by injecting each audit gas into the
GEMS a minimum of two times. The CEMS should be set-up to exclude audit data
from the emissions averages. If this cannot be done, alternative procedures
will be needed to isolate and record analyzer responses to the audit gases.
Except for the exclusion of audit gas response data from calculated emission
averages, the CEMS should be operating in its normal mode.
4.1 AUDIT GAS INJECTION
1. Instruct the CEMS technician to connect the audit gases, as outlined in
Section 3- On the Audit Gas Injection Record (provided in Section 6)
record the time when effluent sampling is interrupted (e.g., when the
sample line is removed from the probe) .
2. Adjust the audit gas delivery rate according to the procedures in
Section 3•
3- Inject each gas until a stable response is obtained. If the CEMS
operates with a periodic sampling and analysis cycle, inject each gas
for a minimum of one complete cycle. Record the beginning time for each
gas injection on the Audit Gas Injection Record.
4.2 NUMBER OF GAS INJECTIONS
1. Each audit gas should be analyzed twice. These analyses should be
separated by the analysis of a different audit gas or a zero gas.
2. If the system responses for the two analyses of the same gas vary from
each other by more than 10% of the gas value, a problem with one of the
injections should be suspected. In this case, a third analysis should
be run. The third analysis should be separated by the analysis of a
different audit gas or a zero gas.
3. If three gas injections are done, calculate a mean response from the two
results which are closest to each other.
15
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4.3 DATA RECORDKEEPING
1. The results of each gas analysis should be recorded on the Audit Results
form. Acceptable accuracy levels for each audit gas are available from
the Inspector's Quick Check Audit Gas Data Sheet. Example forms are
shown in Section 6.
2. Often, a zero level response will be available for each monitoring
channel. For instance, an 0_ audit gas for an extractive CEMS will also
be a zero level audit gas for the S0_ channel. Recording these zero
responses is optional, but is encouraged because they provide additional
CEMS performance data with no additional resource expenditure.
3- A copy of the completed Audit Results Form may be left with the source.
Since the Inspector's Quick Check Audit Gas Data Sheet reveals the
concentrations of the blind audit gases, it should be treated as
confidential. It will not be shown to or left with source personnel.
16
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5- POST-AUDIT ACTIVITIES
Post-audit activities will vary from agency to agency. This section
includes a brief description of several activities that should be done and one
data manipulation activity that should not be done.
5.1 PLOT CEMS RESPONSE AS FUNCTION OF AUDIT GAS CONCENTRATION
A Graphic Presentation of CEMS Response form is provided in Section 6. Use
of this optional presentation of audit data is encouraged. Plot the actual
audit gas concentration along the horizontal axis and the CEMS responses along
the vertical axis. If zero level response data are available, include them on
the plot. By connecting the plotted points, a good estimation for the CEMS
performance over a wide range of concentrations is obtained.
5-2 FILE DATA
Copies of the completed AUDIT DATA FORM should be filed at the agency
according to the agency's filing procedures.
5-3 FOLLOW-UP ACTIVITIES
When the audit reveals unacceptable CEMS accuracy, follow-up activities
should include encouraging the source to remedy the problem and scheduling a
follow-up audit. When the audit reveals acceptable accuracy, the source should
be notified, along with a few words of thanks and appreciation for its
cooperation.
5.4 NO CORRECTIONS OF REPORTED EMISSIONS DATA
Do not "correct" reported emissions data based on the audit results. The
audit results demonstrate the performance of the CEMS at one point in time.
The audit is intended to determine the acceptability of emissions data, and
does not provide a basis for adjustment of the data.
17
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6.0 DATA FORMS
Facsimilies of data forms designed to facilitate gas CEMS audits are
provided in this section. Example forms are also provided showing data
obtained from a hypothetical audit.
18
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CO
o>
OB
GO
09
PRE-AUDIT DATA FORM
Plant Name
Company Name
Plant Contact
Phone Number,
Address
Company Contact
Phone Number
Address
CEMS Type (extractive, point in situ, etc.)
Manufacturer (KVB, LSI, etc.)
EMISSIONS:
Typical
Standard
SO
NO
Other
Diluent
(Ib/mmBtu) (PPM) (Ib/mmBtu) (PPM) (Ib/mmBtu) (PPM)
* Concentration at level of the standard and typical diluent concentration
Analyzer
SO 2
NOx
Diluent
Other
Other
Maker
Model
Fufl Scale VaLte
S/N
Gases
Needed
SO 2
NOX
02
CO 2
Other
Low Level
High Level
Probe Location(s)
Access to Probe Location
Need Gas Transport Line (Y / N)
Length of Transport Line Needed
ft.
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GENERAL AUDIT JNFORMATION
AUDIT DATE:
PLANT CONTACT:
Name
Phone
Address.
AUDIT PARTICIPANTS:
Name Affiliation Phone Number
How is CEMS audit data collected? (Computer screen.
Correction apolied to emissions data?
Correction applied to audit data?
printout, stripchart)
NOTES:
3736 8/88
20
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AUDIT GAS INJECTION RECORD
Plant
Date
Unit No.
Time when effluent sampling is interrupted:
Injection
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
I
Gas
Name
I
Time
Injection
Begins
GEMS Responses
so2
ppm
NO x
ppm
Diluent
Other
Other
Time effluent sampling resumes:
21
3736 8/88
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AUDIT RESULTS FORM
Plant Name
Company
Unit No.
Auditor,
Date
GEMS Sample Location
Measurement
Range
Example
Low SO 2
High SO 2
Zero (optional)
Low NO x
High NO x
Zero (optional)
Low Diluent
High Diluent
Zero (optional)
Other: Low
High
Zero
Other: Low
High
Zero
Gas
Name
SO2 #EX
Gas1
Cone.
Blind
Analysis
#1
154
Analysis
#2
160
Analysis ^
#3
Mean
Response
157
Accuracy
Level
A
1 Write "blind" if gas concentration is to remain unknown to the source.
2 Analysis #3 should be performed only if the difference between analyses #1 and #2 exceeds 10%
of the gas value. If Analysis #3 is performed, use the two analyses with the least difference to
calculate the mean response.
22
3780 6/89
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GRAPHIC PRESENTATION OF CEMS RESPONSE
Plant Name
Company_
Unit No.
Auditor
Date —
CEMS Location.
Measurement Channel
Instrument Span
LU
co
O
D_
CO
UJ
cc
CO
2
LU
O
JJL
IDEAL
RESPONSE
CURVE
GAS VALUE
3780 5/89
23
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INSPECTOR'S QUICK CHECK AUDIT GAS DATA SHEET
Status
Blind
Gas
Examples:
SO2 EX#1
O2 EX#2
Cone.
150 ppm
12.4 %
Accuracy Levels
Acceptable
A <5%
142 - 158
11.8- 13.0
-
-
-
-
-
-
-
-
-
-
-
B< 10%
135 - 165
11.2 - 13.6
-
-
-
-
-
-
-
-
-
-
-
C<15%
127- 173
10.5 - 14.3
-
•
-
-
-
-
-
-
-
-
Unacceptable
D>15%
<126 >174
<10.4 >14.4
< >
< >
< >
< >
< >
< 2
<. >
< >
< >
< >
< >
< >
5 >
1. Each audit gas in the possession of the agency should be included on this sheet.
2. Write "Blind" in the status column beside those gases whose concentrations will remain unknown to source
personnel, ft is recommended that a portion (or all) of the agency's audit gases be designated as blind.
3. Column "Cone.": Write certified value of audit gas in this column to the nearest ppm or 0.1%, as appropriate.
4. Column A: Lower Limit = (Certified Cone.) x (0.95) [round down]
Upper Limit = (Certified Cone.) x( 1.05) [roundup]
Column B: Limits = (Certified Cone) x (0.9) and (1.1) [round as above)
Column C: Limits - (Certified Cone) x (0.85) and (1.15) [round as above)
Column D: Outside Level "C" limits, to the nearest ppm or tenth of percent. 3736 8/8
24
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u
O3
OS
CD
09
PRE-AUDIT DATA FORM
Plant Name
(^->^S-/£/S/3 r,, .y/^- _, „
Company Name
Plant Contact
Phone Number,
Address
Company Contact
Phone Number
Address
J-^ ^_) _ —
CEMS Type (extractive, point in situ, etc.)
Manufacturer (KVB, LSI, etc.) •< f
so,
NO
Other
EMISSIONS: ^2 ,,~ x
(Ib/mmBtu) (PPM) (Ib/mmBtu) (PPM) (Ib/mmBtu) (PPM)
Typical (?- ^' ? ^ ^.5"' J> ? ~i -—
Standard '- ^~ & -T-22. * £?• TV yav • —~~
Diluent
(%) ^
6. '
' Concentration at level of the standard and typical diluent concentration
Analyzer
SO 2
NOx
Diluent
Maker
Model
Other
Ful Scale VaLe
r^
SvN
Gases
Needed
SO 2
NOX
02
CO 2
Other
Low Level
High Level
$-0a —
Probe Location(s)
/C
Access to Probe Location
F/*t,
-
Need Gas Transport Line (Y / N)
Length of Transport Line
ft.
25
-------
GENERAL AUDIT INFORMATION
-r-__^ - <* **
PLUIT CONTACT:
Phnno ' xx , ' • - ///- ~ 1- ^ —
<^.#\-
AUDIT PARTICIPANTS:
Name Affiliation Phone Number
-' 7-
-« -< ** —
How is CEMS audit data collected? (Computer
Correction aoolied to emissions data? ^z-r
Correction applied to audit data? >^-r/ t-*'
screen, printout, stripcnart)
^"j.-«_C/ <=rr\ cS^.// Z*+~e -»• J^»--n ^/CtCl4;
^c/,., -,p/.^ *y ~~r^
NOTES: ^>>? ^i ,^f.#(:t.-r;t>M ^x/^/
-------
AUDIT GAS INJECTION RECORD
Plant
Date
Unit No
Time when effluent sampling is interrupted:
O
Injection
No.
Gas
Name.
Time
Injection
Begins
GEMS Responses
SO
ppm
NO
ppm
Diluent
Other
Other
3
-5"
/
2/0. 3
2
/a j —
Z
/ y .- /
3/V.2.
Z
/•/: 2.6
31 :f.
. 2
- 4,
/
. 7
10
/ 7
a
2.
_ /
3 7
2.
/7
14
15
Time effluent sampling resumes:
3736 8/88
27
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AUDIT RESULTS FORM
Plant Name . €_
Company
Unit No.
/•e,. <^~f_
r/6.
Auditor
y
CEMS Sample Location
Measurement
Range
Example
Low SO 2
High SO 2
Zero (optional)
Low NO %
High NO x
Zero (optional)
Low Diluent
High Diluent
Zero (optional)
Other: Low
High
Zero
Other: Low
High
Zero
Gas
Name
SO #EX
J£^
JT^ Y
SsC<2
fi/Ox 3
&, 0L.
0^ ^
O* 1
//^, &L
Gas1
Cone.
Blind
3^7 /
BJ>»J
O
8/i»,l
^rt
0
M^
B/,-«l
0
Analysis
#1
154
3/y
?/
-------
GRAPHIC PRESENTATION OF CEMS RESPONSE
Plant Name ^ c-~^/£.
Company — •*-_.„/<>
Unrt No. ~
CEMS Location S~/cJ.
/^r,<,^J,^ *-/: -i_*~, /h/»),f*2.
£/ — " '
r~t f *^ ~^^~" J -^ / ^? 5 J?
MPa^lirPm^rrt P.hannpl ^ C/->~
o
a.
01
cr
C/3
2
01
I | | | | I | | | | | | || MM I I M I I I I MM II I I I I I I I
300 6a° 7l"~
GAS VALUE (
IDEAL
RESPONSE
CURVE
3736 8/8£
29
-------
GRAPHIC PRESENTATION OF GEMS RESPONSE
Plant Name
Company
Unit No.
C *•,. ,*,-• . f_
••."•• Auditor
— Date —
CEMS Location
Measurement Channel
Instrument Span
UJ
at
a:
UJ
M i i liuil n ii In nlni i IIM i IM ti
Cut-*-
IDEAL
RESPONSE
CURVE
GAS VALUE ' ,-/X '
3736
30
-------
GRAPHIC PRESENTATION OF GEMS RESPONSE
Plant Name '-vo
Company -*^*
Unrt No. ^
CEMS Location
"•/?/£. ^'nt.r-'T,^* J/6X -?>, Aud'tnr /rfi'-r.-^e.m /ItJeyr^
~V/
-------
INSPECTOR'S QUICK CHECK AUDIT GAS DATA SHEET
Accuracy Levels
Acceptable
Unacceptable
Status
Gas
Cone.
A 15%
Examples:
SO2 EX#1
150 ppm
142- 158
135- 165
127- 173
5126 >174
Blind
EX#2
12.4%
11.8- 13.0
11.2- 13.6
-14.3 510.4 >14.4
- /3V
J&L 2-
7 - £ JJ
y
**'
> £22.
J&i.
7f
/!/
„«
> 72.3
3
Ptin
52 J - 5
Bin I
/
#5-
. 3 -9-7
. O - -3.0
< 3- 7
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
340/1-89-003
2.
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
Field Inspectors Audit Techniques: Gas GEMS's Which
Accept Calibration Gases
5. REPORT DATE
June 1989
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO.
Wayne E. Reynolds
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Entropy Environmentalists, Inc.
CEM/Engineering Division
PO Box 12291
Rp<;p3rrh Tri'annlo Park NT ?77flQ
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-02-4462
nn |
12. SPONSORING AGEtfCY NAME AND ADDRESS
U. S. EPA, Stationary Source Compliance Division
401 M Street, SW Waterside Mall
Washington, DC 20460
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
Work Assignment Manager: Anthony P. Wayne, U. S. EPA, Region VI
16. ABSTRACT
This document presents guidance for planning and conducting audits of
continuous emission monitoring systems (GEMS's) for gaseous pollutants. It
provides simple, cost effective audit procedures for control agency field
inspectors to verify the accuracy of CEMS data. The audit procedures are based
on the use of audit gases and are applicable only to gas CEMS's configured to
accept calibration gases. The document includes an outline of planning
activities, principles of audit gas injections, procedures for conducting a field
audit, a discussion of post-audit activities, and example data forms.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTlFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Air Pollution Monitoring
Continuous Emission
Monitoring
Gas Audits
Audit Procedures
8. DISTRIBUTION STATEMENT
Release to Public
19. SECURITY CLASS (ThisReport!
Unclassified
21. NO. OF PAGES
36
20. SECURITY CLASS (Thispage)
Unclassified
22. PRICE
EPA Form 2220-1 (R«v. 4-77) PREVIOUS EDITION is OBSOLETE
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