xvEPA
United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
Research Triangle Park NC 27711
EPA-340/1-83-015
January 1983
Stationary Source Compliance Series
Performance
Audit Procedures
for SO2, NOx,
CO2, and O2
Continuous
Emission
Monitors
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EPA-340/1-83-015
Performance Audit Procedures for SO2, NOx,
CO2, and O2 Continuous Emission Monitors
Prepared by:
Entropy Environmentalists, Inc.
Research Triangle Park,
North Carolina
Prepared for:
Louis R. Paley
Stationary Source Compliance Division
United States Environmental Protection Agency
SSCD Contract No. 68-01-6317
Prepared For
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air Quality Planning and Standards
Stationary Source Compilation Division
Washington, D.C. 20460
January 1983 U.S. Environmental Protection Agency
Region 5, Library (5PL-16)
230 S. Dearborn Street, Room 1670
Chicago, -IL 60604
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The Stationary Source Compliance series of reports is issued by the
Office of Air Quality Planning and Standards, U. S. Environmental
Protection Agency, to assist Regional Cffices in activities related to
compliance with implementation plans, new source emission standards,
and hazardous emission standards to be developed under the Clean Air
Act. Copies of Stationary Source Compliance Reports are available -
as supplies permit - from Library Services, U.S. Environmental
Protection Agency, MD-35, Research Triangle Park, North Carolina
27711, or may be obtained, for a nominal cost, from the National
Technical Information Service, 5285 Port Royal Road, Springfield,
Virginia 22151.
This report has been reviewed by the Office of Air Quality Planning
and Standards, U.S. Environmental Protection Agency, and approved for
publication as received from Entropy Environmentalists, Inc. Approval
does not signify that the contents necessarily reflect the views and
policies of the U.S. Environmental Protection Agency, nor does mention
of trade names or commercial products constitute endorsement or
recommendation for use.
ii
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ABSTRACT
As the Environmental Protection Agency and State control agencies place
greater emphasis on the use of S02 and N0x continuous emission monitor (CEM)
data, valid and reliable monitoring results increase in importance. S0_
and NO CEM performance audits conducted by the control agency provide an
A
independent and quantitative evaluation of the accuracy, representativeness,
and reliability of CEM data reported to the agency. Source owners and
operators may also conduct performance audits to evaluate their installed
CEMS and to diagnose operating problems.
This report presents detailed performance audit procedures for a variety
of currently available S0_ and NO CEMS. Specific procedures for conducting
t X
(1) initial monitor inspections/calibration checks, (2) calibration error
tests, (3) stratification tests at monitor sampling locations, and
(4) relative accuracy tests are included for the following monitoring
systems: (1) LSI SM810 S02/N0 and CM50 02 monitors, (2) DuJbnt 460 S02/N0x
and Thermox 02 monitors, (3) Contraves-Goerz GEM 100 S02/N0/C02 monitors, and
(4) Environmental Data Corporation DIGI 1400 SO /N0/C02 monitors. These
procedures may be adapted to other types of gas emission monitoring systems.
iii
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TABLE OF CONTENTS
Section 1. Introduction 1
Section 2. Testing Methodology 3
2.1 Initial Monitor Inspection/Calibration Check 3
2.2 Calibration Error Test 4
2.3 Stratification Test 5
2.4 Relative Accuracy Testing 7
Section 3. Lear Siegler SMS10 S02/N0 - CM50 02 Audit Procedures. ... 11
3.1 Principle of Operation 11
3.1.1 LSI SM810 SO /NO Monitor 11
3.1.2 LSI CM50 02 Monitor 12
3.2 Initial Monitor Inspection/Calibration Check 13
3.2.1 Monitor Inspection - SM810 SO /NO Monitor ... 13
3.2.2 Calibration Check 14
3.2.3 Temperature Compensation Check (SMS10 Only) . . 15
3.3 Calibration Error Test . 16
3.4 Stratification and Relative Accuracy Tests 18
Section 4. DuPont 460 SO./NO - Thermox 0~ Audit Procedures 19
2 x 2
4.1 Principle of Operation 19
4.1.1 DuPont 460 S02/N0 Monitor 19
4.1.2 Thermox 02 Monitor 19
4.2 Initial Monitor Inspection/Calibration Check 20
4.2.1 Monitor Inspection - DuPont 460 S02/N0x
Monitor 20
4.2.2 Calibration Check 22
4.3 Calibration Error Determination 23
4.4 Stratification and Relative Accuracy Tests 24
Section 5. Contraves-Goerz GEM-100 S02/N0/C0 Audit Procedures .... 27
5.1 Principle of Operation 27
5.2 Initial Monitor Inspection/Calibration Check 27
5.2.1 Monitor Inspection 27
5.2.2 Internal Calibration Check 28
5.2.3 Temperature Compensation Check 29
5.3 Calibration Error Test 29
5.4 Stratification and Relative Accuracy Tests 29
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Table of Contents
(continued)
Section 6.
Section 7.
Environmental Data Corporation DIGI Series 1400
SO /NO/CO Audit Procedures 31
6.1 Principle of Operation 31
6.2 Initial Monitor Inspection/Calibration Check 32
... 32
... 32
6.2.1 Monitor Inspection ....
6.2.2 Internal Calibration Check
6.3 Calibration Error Test 33
6.4 Stratification and Relative Accuracy Tests 33
Quality Assurance Procedures 35
7.1 Method 3 35
7.2 Method 6 36
7.3 Method 7 37
Appendices 39
Appendix A. Stratification Testing Methodology for
Gaseous Effluent Constituents
Appendix B. Reference Method Procedures -
Reference Method 3
Alternative Method for Stack Gas Moisture
Determination
Reference Method 6
Reference Method 7
VI
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1. INTRODUCTION
The EPA and state air pollution control agencies are rapidly expanding the
scope and implementation of continuous emission monitoring programs and placing
greater importance on the use of continuous emission monitor (CEM) data to
achieve sustained emission reductions. In some cases, CEM data are used to
determine compliance with applicable emission standards and pollutant control
requirements.
For continuous monitoring regulations to be effective, monitor-specific
field performance audit procedures are necessary to qualify and to quantify the
validity of the CEM data. These procedures must provide consistently valid
results and must apply to a wide range of regulatory, source, and monitor
conditions.
This document presents field performance audit procedures for CEMS from
four different major manufacturers. These monitor-specific field performance
audit procedures were developed using both the manufacturer's operational
manuals and first-hand experience with the individual monitors. Section 2 of
this report describes general test procedures that are common to each monitor;
Sections 3 through 6 outline the monitor-specific audit procedures for the Lear
Siegler SM810-CM50, the DuBont 460-Thermox, the Contraves-Goerz GEM-100, and
the EDC DIGI Series 1400 monitoring systems, respectively. Section 7 describes
quality assurance procedures for gas CEM performance audits. The Appendix
contains specific sampling and analysis procedures for the stratification and
relative accuracy method tests required in gas monitor audits.
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2. TESTING METHODOLOGY
Performance audits of gas CEMS include: (1) an initial monitor inspection
and calibration check, (2) a calibration error test (for those monitors which
accept calibration gases), (3) a stratification test, and (4) a relative
accuracy test. General procedures for conducting each part of the audit are
discussed below. Monitor-specific procedures are provided in Sections 3 through
6; specific sampling and analysis procedures for the stratification and the
reference method testing of the relative accuracy test are included in the
Appendix.
2.1 INITIAL MONITOR INSPECTION/CALIBRATION CHECK
An inspection of the installed monitoring system is conducted at the
outset of the performance audit: (1) to determine if the monitoring system is
fully operational, (2) to identify and obtain values for monitor operating
parameters necessary for conducting the audit, and (3) to ensure that the
tester understands the data recording system. Since the performance audit
provides a measure of the capability of the monitor to provide valid data,
operational problems identified during the inspection should be corrected by
the source representative before the other audit activities are conducted.
A calibration check of the monitoring system is performed by having the
source representative (operator) conduct the required daily zero and span check
routine. As a part of this procedure, the operator should adjust the
monitoring system if the observed zero or span drift exceeds the applicable
limits. Therefore, at the conclusion of the calibration check procedure (and
the check of auxiliary monitoring parameters for some monitoring systems), the
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CEMS should be fully operational and properly calibrated according to the
normal practices of the CEMS operator.
2.2 CALIBRATION ERROR TEST
A calibration error test is performed for pollutant monitors that accept
gas injections. Zero, mid (45-55% of monitor span), and high (85-95% of monitor
span) range calibration gases are used for the calibration error test. In
addition, a low (20-30% of monitor span) range calibration gas is also injected
to verify the linearity of the monitor.
A three point calibration error test is performed for the diluent monitors
that accept gas injections. The following calibration gases are used: low
(1-3% 02 or 1-3% C02), mid (6-10% 02 or 5-8% C02), and high (air for 02 or
12-15% C02). (The high range test for oxygen monitors cannot be performed
unless the monitor span is >^ 21% 0 .)
All gases used in conducting calibration error tests must be analyzed
prior to use. Two methods are acceptable for establishing the values of
calibration gases: (1) EPA Traceability Protocol No. 1, and (2) analysis with
Reference Methods 3, 6, and 7 utilizing the acceptance criteria for such
analysis included in Paragraph 6.1.1 of the proposed revisions to Performance
Specification 2 (Federal Register, Vol. 44, No. 197, October 10, 1979).
For the calibration error test, a total of 20 nonconsecutive measurements
for pollutant monitors and 15 nonconsecutive measurements for pollutant
monitors are obtained by alternately injecting each of the calibration gases
(e.g., zero, low, mid, high, low, mid, zero, high, etc.). The gas injections
(i.e., proper flow rate and delivery pressure) must be performed in accordance
with the applicable monitor-specific procedures (see Sections 3 and 4 of this
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report.
For the calibration error test, the responses of the pollutant and/or
diluent monitoring channels are determined from the permanent data record used
for determining excess emissions which are reported to the control agency.
Comparison of the responses indicated on the permanent data record and backup
recording systems or instrument panel meters (when used by the operator to
adjust the monitoring system) should also be performed. For each gas injected
during the calibration error test, the mean difference and 95? confidence
interval of the five measurements are calculated and expressed both on an
absolute basis (units of concentration) and a relative basis (percentage of
calibration gas value). The calibration error is calculated as the sum of the
mean difference and 95? confidence interval, and is expressed as a percentage
of the test gas concentration. The calibration error test results for only the
mid and high range gases are compared to the <_ 5% limit of Performance
Specification 2 for pollutant monitors, and to the same <_ 5% limit for diluent
monitors (proposed revision to Performance Specification 3, Federal Register,
October 10, 1979).
2.3 STRATIFICATION TEST
A stratification test is performed to evaluate the representativeness of
the CEM sampling location and to determine a representative location for
conducting Reference Method sampling for the relative accuracy test. The
stratification test methodology entails the use of an extractive, transportable
monitoring system, and is designed to detect the presence of effluent
stratification. It does not provide a quantitative characterization of the
effluent stratification profile, nor does it provide sufficient information to
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determine if a particular measurement point or path at a stratified location
provides measurements which are consistently representative of emissions.
The procedures for conducting stratification tests are detailed in
Appendix A, "Stratification Testing Methodology for Gaseous Effluent
Constituents." However, for gas CEM performance audits, these procedures must
be adapted to provide appropriate results for the monitor- and source-specific
conditions encountered. The following sampling strategies address the most
commonly encountered situations:
(1) For sources where only a pollutant or diluent monitor is
installed, a stratification test for the constituent of interest
should be conducted at the monitor installation location.
(2) For sources where both pollutant and diluent monitors are
installed at the same location and view the same portion of the
effluent stream, concurrent stratification tests for each
constituent of interest should be conducted at the monitoring
location. The measurement results for each sample point
expressed in units of the applicable standard should be examined
to determine if stratification is present.
(3) For sources where both pollutant and diluent monitors are
installed at the same location, but view separate portions of
the effluent stream, concurrent stratification tests for each
constituent of interest should be conducted at the monitoring
location. The concentration measurements of each constituent
should be examined independently to determine if stratification
of either component exists at the monitoring location.
(4) For sources where pollutant and diluent monitors are installed
at separate locations, concurrent stratification tests for each
constituent of interest should be conducted at the pollutant
monitoring location. The concentration measurements of each
constituent should be examined independently to determine if
stratification of either component exists at the pollutant
monitoring location. In addition, if the diluent monitor is
installed at a potentially stratified location, a diluent
stratification test should be conducted at the diluent
monitoring location. Finally, if air in-leakage may occur
between the diluent and pollutant monitoring locations, and if
diluent stratification does not exist at either monitoring
location, then simultaneous diluent concentration measurements
should be made at both locations to detect and/or to quantify
air in-leakage.
(5) For sources where physical constraints require that relative
accuracy sampling be conducted at a location other than the
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monitoring location, concurrent stratification tests for each
constituent of interest should be conducted, and the
concentration measurements obtained at each sampling point
should be examined independently to determine if stratification
of any component exists at the testing location.
In many cases it is impossible to conduct full traverses of the stack/duct
cross section during stratification tests due to the lack of sampling ports or
other physical constaints. In these situations, additional sampling points
should be included on the traverses which can be made (at least nine points
should be sampled in all cases). Conclusions regarding the presence of
stratification must reflect the limitations of the testing performed.
2.4 RELATIVE ACCURACY TESTING
Sampling and analysis for relative accuracy determinations are conducted
according to the procedures contained within the revisions to Performance
Specifications 2 and 3 reproposed January 26, 1981 (Federal Register, Vol. 46,
No. 16). Testing is conducted to determine both the relative accuracy of the
combined pollutant/diluent monitoring system in units of the standard, as well
as the relative accuracy of each monitoring channel in units of concentration.
Where stratification test results indicate that effluent stratification
exists, the Reference Method sampling points are located in accordance with the
procedures described in the proposed revisions to Performance Specification 2
(January 26, 1981). Otherwise, a single Reference Method sampling point is
located adjacent to the installed CEM measurement point or path.
Reference Method tests (Method 6 for SC- , Method 7 for NO , Method 3 for
COp or Op, and Alternative Method 4 for moisture) are performed in accordance
with the procedures prescribed in Appendix A, 40 CFR 60 (see Appendix B of this
report). All effluent samples are obtained via a single, 5/8 inch O.D.
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borosilicate glass probe. The probe inlet is packed with borosilicate glass
wool to remove participate matter from the effluent sample. In addition, the
probe is incased within a stainless steel sheath, and is heated to prevent
condensation of water vapor within the effluent sample stream. The probe
outlet is connected to a heated manifold from which connections can be made to
appropriate sampling trains. Stainless steel valves are provided between the
manifold and the sampling train connections. The temperature of the effluent
sample stream within the manifold is monitored with a thermocouple to ensure
that water vapor condensation is prevented.
Effluent samples are obtained concurrently during (at a minimum) 20-minute
sampling runs. (Longer sampling runs are occasionally used when low effluent
concentrations necessitate larger sample volumes in order to maintain desired
accuracy levels.) No more than one sampling run is conducted in any 1-hour
period.
EPA Method 3 is employed to obtain integrated, average dry-basis
concentrations of C02 and 0-. Triplicate Orsat analysis is performed
immediately after sample acquisition.
EPA Method 6 is used to determine integrated average dry basis
concentrations of S0?. Midget impingers rather than midget bubblers are used
to contain the isopropanol solution which removes sulfuric acid mist from the
sample stream. The outlet temperature of the final, dry impinger of the
sampling train is not monitored, since it has been demonstrated that the S0?
collection efficiency of the sampling train is greater than 99 percent when the
impingers are cooled in an ice bath. Titrations using barium chloride solution
are performed on-site.
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Dry basis, NO concentrations are obtained using EPA Method 7. The three
grab samples that constitute a sampling run are spaced evenly in time over the
run. In lieu of 50-mL volumetric flasks, 100-mL volumetric flasks are used in
the analysis phase; the volumes of aliquots are adjusted accordingly. The
arithmetic mean of the three grab sample results is reported as the N0x
concentration for the sampling run.
Most continuous monitoring systems analyze the effluent concentrations on
a wet basis. The Reference Method results are on a dry basis; therefore, stack
gas moisture determinations are necessary to convert measurements to a
consistent basis. Moisture determinations are performed according to the
procedures described in "An Alternative Method for Stack Gas Moisture
Determination" (see Appendix B). Drierite, rather than silica gel, is used in
a Mae West midget impinger to capture water vapor penetrating the preceding two
impingers of the train. Samples are obtained at a flow rate of 2 L/min. Water
vapor concentrations are computed after each sampling run based upon the
results from the final weighing of each train.
For the relative accuracy test, the CEMS data should be obtained from the
permanent data record used for reporting of excess emissions. Where electronic
data recording systems which average and display monitoring data on a basis
that is inappropriate for direct comparison with the Reference Method results
are used, the CEMS data may be determined from a backup recording system, if
available. In this situation, a comparison of the permanent data record and
the backup record for each hour of the relative accuracy test should be
performed.
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3. LEAR SIEGLER SM810 S02/N0 - CM50
AUDIT PROCEDURES
3.1 PRINCIPLE OF OPERATION
3.1.1 LSI SMS 10 S02/N0 Monitor
The LSI SM810 is a single point, in-situ, dual pass, second derivative
spectrophotometer that employs ultraviolet light for the measurement of SO,, and
NO. The ultraviolet light is generated in the transceiver unit and projected
down the probe (normally 6-8 feet long) to the optical cavity located at the
end of the probe. Effluent gases diffuse into the optical cavity through a
ceramic thimble which protects against particulate contamination. A portion of
the ultraviolet light is absorbed by the S02 and NO, and the remaining light is
reflected back to the .transceiver. An oscillating monochronometer then
produces a detector output signal proportional to the curvature of the
ultraviolet absorbance spectra at different points in the ultraviolet spectrum
for S02 and NO. A converter unit conditions the transceiver output to produce
signals proportional to the concentrations of S0_ and NO in parts per million
(ppm) . Since S02 exhibits a narrow band absorption at the wavelengths where NO
is measured, additional electronic circuitry subtracts the S02 interference
from the NO measurements.
The SM810 transceiver employs an internal zero device and a sealed gas
cell for upscale calibration checks. The SM810 monitor is also equipped to
accept the injection of calibration gases into the optical measurement cavity;
the gas injection port is located on the flange of the probe.
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3.1.2 LSI CM50 02 Monitor
The LSI CM50 is an in-situ, electrocatalytic oxygen analyzer. As the
CM50 samples combustion gases, the partial pressure of the effluent oxygen in
the sample side of the analyzer cell is lower than the partial pressure of
oxygen in the reference side, which is generally that of air. When the cell
is kept at a temperature of approximately 850°C, oxygen molecules in the
reference side pick up electrons at the electrode-electrolyte interface. The
CM50's porous ceramic material (Zr02) has the special property of high
conductivity for oxygen ions. This occurs because the metal ions form a
perfect crystal lattice in the material, whereas the oxygen ions do not,
resulting in vacancies. Heating the zirconium oxide causes the vacancies and
oxygen ions to move about. The oxygen ions migrate to the electrode on the
sample side of the cell, release electrons to the electrode, and emerge as
oxygen molecules. The resultant EMF is a logarithmic function of oxygen
partial pressures. A linearizer circuit processes the resultant EMF to
provide an output equivalent to the oxygen concentration (% 02).
The CM50 0^ monitor is designed to accept injection of calibration gases.
The gas injection port is located on the flange of the sampling probe.
Normally, a low range 0^ gas and ambient air are used to calibrate the
monitor.
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3.2 INITIAL MONITOR INSPECTION/CALIBRATION CHECK
3.2.1 Monitor Inspection -
SMS 10 S02/N0 Monitor
Perform the following initial monitor checks at the converter unit to
determine whether the monitor is functioning properly.
Check the four system fault indicators on the front panel of the converter
unit.
OPERATE - The "OPERATE" light should be on. If this light is
not on, the control unit has lost power or has
experienced a power supply failure.
SCANNER - The "SCANNER" fault light should be off. If on, a
change in the scanner amplitude has occurred which
may affect instrument calibration. The extent of
this problem will be checked by the calibration gas
injections as described in Section 3.1.1* of these
procedures.
REF -The "REF" fault light should be off. If on, the
light returning to the photomultiplier tube is
below normal operating limits.
HEATER - The "HEATER" fault light should be off. If on, the
temperature controller on the transceiver has
failed, or power to the transceiver has been
interrupted.
Check the reference, input, and temperature signals at the control unit by
placing the meter select switch in the proper position. The reference signal
measures the light intensity level returning to the photomultiplier tube. If
the reference signal reading is not within the green band area (due to
contamination of the optical components in the analytical cavity, and/or to
lamp degradation) , have the monitor repaired by the source representative
(operator) before proceeding with the audit. Note the input signal during the
S02 and NO sampling cycles.
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Check the effluent temperature (°F) at the monitor probe tip by placing
the meter select switch in the "TEMP" position. A zero or offscale reading
means the monitor is not functioning properly; postpone the audit until repairs
are made by the operator.
CM50_Og Monitor
Check the four operational parameter indicators located on the front panel
of the control unit to determine whether the monitor is functioning properly.
These indicators are:
TEMP FAULT - The temperature fault light should be off. If on, the
analyzer cell is not at the proper temperature. Postpone
the audit until corrective action is taken by the source.
HI CAL/LO CAL - These calibration lights should be lit only when a
calibration cycle is performed.
RANGE - A selectable range of 2.5%, 10J, and 25% 02 are available.
ALARM - Preset alarms are illuminated when the monitor and/or
process parameter indicators report data below or above
preset monitor limits. (These lights do not indicate
improper monitor operation.)
Data Recorders
Visually check the S02, NO, and 02 data recorders to see whether signals
are being recorded. If the data recorders are off-scale or are not recording
data, have the operator correct the problem before proceeding with the audit.
3. 2. 2 Calibration Check
Ask the operator to explain the conventions used for interpreting the
strip chart data (e.g., identification of the zero level, scale factor, and/or
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maximun data display for each monitoring channel). Also, if the monitor is
interfaced with a computer or other electronic data recorder, ask the operator
to explain fully the method used for averaging and displaying the concentration
measurements, calibration data, and for calculating emission measurements. Ask
the operator for the correct zero and upscale calibration check values for
each monitoring channel.
Have the source perform the daily monitor calibration routine. Record the
$1810 SOp and NO monitor responses for the internal zero and span checks.
Record the CM50 0^ monitor responses for the low and high range calibration
gases; also record the gas injection rate. If the correct recorder responses
(i.e., ^2.5% of span) are not obtained for both the zero (or low range) and
span checks for all of the monitoring channels, have the source adjust the
monitor before proceeding with the audit.
3.2.3 Temperature Compensation Check (SM810 Only)
The effluent temperature is measured by a thermocouple located on the end
of the SM810 monitor probe and is used by the temperature compensation circuit
to adjust the second-derivative signal amplitude and the resulting S02 and NO
concentration output levels for temperature variations.
Check the monitor thermocouple calibration by comparing the monitor stack
gas temperature readings to actual effluent gas temperature measurements made
alongside the monitor probe tip. If the monitor probe and effluent gas
temperature measurements do not agree within +_ 2%, have the source adjust the
monitor for the proper stack gas temperature. If adjustments to the
temperature measurement/temperature compensation systems are made, repeat the
calibration check procedure before proceeding with the audit.
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3.3 CALIBRATION ERROR TEST
The calibration error test procedures and specific calibration gases used
for this test are described in Section 2.2 of this report. Before initiating
the test, the proper calibration gas injection rate must be established for
both the SM810 and CM50 monitors. Establishing the proper gas flow rate for
the SM810 monitor is particularly critical. If the calibration gas flow rate
is too low, the effluent gases will diffuse into the probe tip cavity, dilute
the calibration gas, and cause an incorrect monitor response for the
calibration gas concentration. If the flow rate is too high, buildup of
pressure in the cell cavity (i.e., an increase in molecules per unit volume)
and/or a difference between the calibration gas temperature and the effluent
temperature (i.e., the temperature compensation circuit will not adjust the
electronics for the proper temperature) may cause an error in the readings for
the calibration gas.
The following procedures should be used for the SM810 monitor:
(1) Attach the flow meters and flow control valves between the
calibration gas cylinders and the injection ports and adjust the
regulator delivery pressure to about 10 psig for each of the
calibration gases.
(2) Inject a high range calibration gas (use SO,, for S0?/N0 and SO
monitors; use NO only for NO monitors) . Slowly open the flow
control valve until the gas injection rate reaches 2. OL/min
(the gas injection rate specified by the manufacturer) . Inject
the gas for at least U minutes for a single gas monitor (1
minute sample/hold circuit) or at least 6 minutes for a dual gas
monitor (2 minute sample/hold circuit) , or until the monitor
indicates a stable response for two successive sampling periods.
Record both the time required to achieve a stable response and
the concentration value indicated by the monitor.
(3) Increase the gas injection rate to 2.5 L/min. Allow sufficient
time for the monitor response to stabilize and record the
concentration value indicated by the monitor. If the monitor
response at 2.5 L/min is the same as 2.0 L/min, all gases should
be injected at 2.OL/min for the calibration error test; no
further preliminary testing is necessary.
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(4) If the monitor response at 2.5 L/min is greater than the
response at 2.0 L/min, adjust the gas injection rate to
1.5 L/min, allow sufficient time to obtain a stable response,
and record the concentration value indicated by the monitor. If
the responses at 1.5 L/min and 2.0 L/min are the same, inject
gas at approximately 1.7 L/min for the calibration error test;
no further preliminary testing is necessary.
(5) If the monitor response at 1.5 L/min is less than the response
at 2.0 L/min, repeat step (4) using 1 L/min gas injection rates.
Inject all gases at 1.2 L/min if the responses at 1.0 L/min and
1.5 L/min are the same. If not, proceed with step (6).
(6) Inject a zero gas at 1.5 L/min and record the monitor response
after it stabilizes. (A small positive offset will probably be
observed since the monitor amplifies positive noise and ignores
the negative noise at the zero concentration level) . Decrease
the zero gas injection rate in intervals of 0.25 L/min until an
increase in the stablized zero gas response is seen. Ihis
indicates that the gas injection rate is too low to prevent the
diffusion of stack gases into the measurement cavity. Inject all
gases for the calibration error test at a rate of 0.25 L/min
greater than the flow rate which exhibits an increased zero
response.
(7) Record the flow rate used for the calibration error test and the
time allowed for injection of each gas.
The response of the CM50 0^ monitor is much less sensitive to calibration
gas injection rates than the SM810 monitor. For the CM50 monitor, 0
calibration gases should initially be injected at the same flow rate as
observed during the daily calibration procedure. Calibration gases should also
be injected at 0.5 L/min above and below the initial injection rate to verify
that the monitor response is unaffected. If a consistent monitor response is
not obtained during these preliminary tests, then a procedure equivalent to the
above steps for the SM810 monitor should be followed to determine the proper
calibration gas injection rate.
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3. M STRATIFICATION AND RELATIVE ACCURACY TESTS
Before initiating the relative accuracy test, perform a statification test
at the monitor location using the procedures presented in Section 2.3 and
Appendix A of this document. Conduct the relative accuracy test in accordance
with the procedures in Section 2.4 and the Reference Method procedures
delineated in Appendix B of this document. Moisture testing must be conducted
during the relative accuracy tests to facilitate comparison of the wet basis
SM810/CM50 concentration measurements and the dry basis Reference Method
results.
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4. DUPONT 160 S02/N0x - THERMOX 02
AUDIT PROCEDURES
4.1 PRINCIPLE OF OPERATION
4.1.1 DuPont 460 S02/N0x Monitor
The DuPont 460 S0p/N0 gas analyzer is an extractive monitor which uses
<— X
differential ultraviolet radiation adsorption to measure concentrations of
sulfur dioxide and oxides of nitrogen. The monitor sequentially cycles through
a sampling mode and a purge mode for the SOp and NO monitoring channels.
First, the sample cell and line are purged with ambient air and the S02
channel's zero is automatically adjusted. Next, a sample is drawn from the
effluent stream through heated sample lines equipped with filters for the
removal of particulate matter. The sample is then pulled through the
condensate trap and into the sample cell, where the SO,, concentration is
measured. Tne sample cell and line are then purged with ambient air, and the
N02 channel's zero is automatically adjusted. Finally, a second effluent
sample is pulled through the condensate trap and into the sampling cell where
the N02 concentration is measured. The cell is then sealed) and oxygen is
injected into the cell to convert the NO in the sample to NO,, which is
subsequently measured and recorded as the NO concentration. At this point,
A
the cycle is repeated. Tne SOp and NO measurements are converted
electronically to an input signal for the data recording system.
4.1.2 Thermox 02 Monitor
The Thermox 02 monitor is an extractive analyzer which employs an
electrocatalytic process in the analysis of oxygen. It is installed within the
DuPont 460 analyzer cabinet in a functionally parallel arrangement with the
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DuPont 460 sample cell. Curing the S02 portion of the DuPont sampling cycle,
combustion gases enter the analytical chambers of both the DuPont and Thermox
analyzers and concentrations of S0_ and Op are measured concurrently.
In the Thermox 0^ monitor, the partial pressure of the oxygen in the
sample side of the cell is lower than the partial pressure of the oxygen in the
reference side, which is generally that of air. The cell is kept at a
temperature of about 850°C; at this temperature, oxygen molecules in the
reference side will pick up electrons at the electrode-electrolyte interface.
The cell is composed of porous ceramic material which has the special property
of high conductivity for oxygen ions. This occurs because the metal ions form
a perfect crystal lattice in the material, whereas the oxygen ions do not,
resulting in vacancies. Heating this material causes the vacancies and oxygen
ions to move about. The oxygen ions migrate to the electrode on the sample
side of the cell, release electrons to the electrode, and emerge as oxygen
molecules. The resultant EMF is a logarithmic function of oxygen partial
pressures. Also, a linearizer circuit processes this EMF to give an output in
units of concentration (% 0^). The 02 measurements derived by the Thermox
analyzer are converted electronically to an input signal to the data recording
system .
4.2 INITIAL MONITOR INSPECTION/ CALIBRATION CHECK
4. 2. 1 Monitor Inspection -
DuPont 460 SOo/NO Monitor
Various types of control units are used for the DuPont 460 S05/N0
£ X
analyzers; therefore, no universal monitor checks can be established. Check
the control unit to determine that power is being supplied. Visually inspect
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the monitor to see whether it is cycling and supplying an output signal to
drive a data recorder. If there are any problems in these areas, do not
continue with the performance audit until the problems have been corrected by
the source representative (operator) .
Various types and configurations of field units (analyzer cabinets) are
used for the DjPont 460 S02/N0x analyzers. Visually check the monitor
parameters against the factory supplied specification sheets (e.g., sample cell
pressures, air regulator supply and working air pressures, oxygen pressure (NO
A
monitors only), sample flows, the cycling of pnuematic control valves, and the
sample line heater voltage/cur rent levels) . Make sure that these monitoring
system functions are working properly (corrected by the operator, if necessary)
before continuing with the audit. Record the sample cell pressure and sample
flow rate for the S02 and N02 channels. Visually determine the location at
which calibration gases are injected in the monitoring system. Note the
cylinder gauge presure and regulator delivery pressures for each calibration
gas.
Thermox 0^, Monitor
Check the Thermox control unit to see that power is being supplied to the
monitor and that the presence of an output signal is indicated by the panel
meter. At the IXaPont field unit, observe and record the 0_ sample flow rate
during the SO sampling cycle. Determine the location where calibration gases
are injected into the monitoring system. Note the cylinder gauge pressure and
regulator outlet pressure for each 0« calibration gas.
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DuPont/Thermox Data Recorder
Visually check the SC>2, NOX, and Op data recorders to see whether signals
are being recorded. If the data recorders are off-scale or are not recording
data, have the operator correct this problem before continuing the audit
1. 2. 2 Calibration Check
Ask the operator to explain the conventions used for interpreting the
strip chart data (e.g., identification of the zero level, scale factor, and/or
maximum data display for each monitoring channel). Also, if the monitor is
interfaced with a computer or other electronic data recorder, ask the operator
to explain fully the method used for averaging and displaying the concentration
measurements, calibration data, and for calculating emission measurements. Ask
the operator for the correct zero and upscale calibration check values for each
monitoring channel. Some DuFbnt 460 monitors are supplied with glass filters
to simulate a specific gas concentration. The values of these filters are
included with the factory specification sheets. All DuPont 460 S02/N0x and
Thermox 0 monitors should be equipped for injection of calibration gases for
the daily zero and span checks. For the Thermox monitor, a low range check
(e.g., 0.8% 0?) should be substituted for the zero check.
Have the operator perform the daily monitor calibration routine. Record
the zero and upscale calibration responses for each monitoring channel. If the
correct recorder responses (i.e., +_ 2.5% of span) are not obtained for both the
zero and span gas injections for each monitoring channel, have the operator
adjust the monitor before proceeding with the audit.
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it. 3 CALIBRATION ERROR DETERMINATION
Zero gases and upscale calibration gases must be introduced to the
Du Pont/Therm ox monitoring system at the junction of the sample probe outlet and
the heated sampling lines. For some DuFbnt M60 Thermox monitors, the injection
of calibration gases at the sampling probe outlet may be accomplished from
remote injection ports, and may be controlled by operation of solenoid values.
Otherwise, the manual gas injection procedure described below should be used.
The calibration error test procedures and specific calibration gases used for
this test are described in Section 2.2 of this report. Before initiating the
test, the proper conditions for injecting the gases must be carefully
established.
Depress the calibration cycle button to activate a solenoid valve that
closes off the monitor sample probe and opens the calibration gas lines to the
monitor. Adjust the calibration gas flow rate to provide the same sample flow
rate for calibration gases as observed during the daily calibration. Continue
to inject each gas until consecutive recorded responses for that gas are
identical. These multiple injections are important since the initial injection
may have occurred in mid-cycle; to obtain a correct reading, the calibration
gas must be injected into the monitoring system at the beginning of a
calibration cycle.
If calibration gas ports are not available, remove the sample line from
the monitor probe. Insert a tee in the sample line, and attach a flow meter
and flow control valve to one leg of the tee. Leave the third leg open to the
atmosphere. Attach the flow control valve and a flow meter to a calibration
gas cylinder, and adjust the regulator pressure to approximately 10 psig. Open
23
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the flow control valve until an 8 cfh reading is obtained on the flow meter.
Allow the monitor to draw its own sample during the calibration cycle. Vent
the excess calibration gas through the third leg of the tee. Allow the monitor
to run through several cycles, until respective portions of consecutive cycles
are identical. Since the Thermox 0? monitor is incorporated within the
DuPont 460, introduce the calibration gases into the Ihermox in the same manner
as the gases for the DuPont 460 monitor.
4.4 STRATIFICATION AND RELATIVE ACCURACY TESTS
Before initiating the relative accuracy test, perform a statification test
at the monitor location using the procedures presented in Section 2.3 and
Appendix A of this document. Conduct the relative accuracy test in accordance
with the procedures in Section 2.4 and the Reference Method procedures
delineated in Appendix B of this document.
The DuPont 460 S02/N0 monitoring system may remove a portion of the
effluent moisture from the sample stream and provides effluent measurements on
a "partially" wet basis. Therefore, moisture determinations may be required at
either of two locations: (1) the same location as the Reference Method probes
or (2) at the monitor's condensate trap. At some sources the moisture content
of the monitor-analyzed sample need not be measured during relative accuracy
tests. The appropriate moisture determination procedure and sampling location
must be determined for the particular effluent conditions and monitor
operation.
The following list presents the appropriate moisture determination method
and sampling location for specific conditions.
24
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1. Reference Method sampling at monitor location:
This method is utilized if the effluent stream is not saturated at the
monitor location and if the analyzer sample stream is not saturated at
the exit of the condensate trap.
2. Reference Method sampling at monitor condensate trap:
This method is utilized if the effluent stream is
saturated/supersaturated at the monitor location and if the
monitor-extracted sample stream is not saturated at the exit of the
condensate trap.
3. Theoretical moisture determination:
This method is utilized if the monitor-extracted sample stream is
saturated at the exit of the condensate trap. If this situation
exists, the temperature of the condensation trap must be monitored,
and the sample stream moisture content is determined through the use
of steam tables or psychrometric charts adjusted to the sample stream
pressure.
25
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5. CONTRAVES-GOERZ GEM-100 SC>2/NO/C02
AUDIT PROCEDURES
5.1 PRINCIPLE OF OPERATION
The Contraves-Goerz GEM-100 is a single pass, cross-stack, in-situ monitor
utilizing a non-dispersive infrared analyzer which compares the absorption of
selected wavelengths by the effluent stream with reference values, thereby
correlating the relative absorption value to the gas concentration of interest.
The monitoring system is comprised of three components: (1) a stack-mounted
infrared source, (2) a stack-mounted analyzer, and (3) a control/display unit
that provides strip chart records of SO,,, C02, and NO concentrations and
effluent temperature, a run/calibrate switch, and three system status
indicators. The GEM-100 analyzer employs internal sealed gas cells and an
alternative infrared light source to provide a single-point upscale calibration
check for each monitoring channel.
5.2 INITIAL MONITOR INSPECTION/CALIBRATION CHECK
5.2.1 Monitor Inspection
First, check the control/display unit. The control unit is equipped with
one two-pen recorder and one three-pen recorder. (The third pen records CO
measurements, provided that this function is incorporated into the monitoring
system.) Check these recorders to verify that all pens are on scale.
The control unit also includes three system status indicators and a
run/calibration switch. Check these as follows:
27
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POWER FAILURE - This red light should be off. When lit, the
monitoring system has lost power.
WINDOW DIRTY - This red light should be off. When lit, one of
several problems associated with the stack source
IR signal is indicated.
CAL STATUS - This red light may either be off or lit; when lit,
the analyzer is in a calibration mode.
RUN/CALIBRATE - This switch activates the calibration mode of the
monitor. The switch should be in the "RUN"
position for normal operation.
Any problems with the system status indicators and their associated
subsystems should be corrected by a source representative (operator) before
resumption of the audit.
5.2.2 Internal Calibration Check
Ask the operator to explain the conventions used for interpreting the
strip chart data (e.g., identification of the zero level, scale factor, and/or
maximum display value for each monitoring channel). Also, if the mon-tor is
interfaced with a computer or other electronic data recorder, ask the operator
to explain fully the method used for averaging and displaying concentration
measurements, calibration data, and calculated emission measurements. Ask the
operator for the correct calibration check values for each monitoring channel.
Have the operator perform the daily monitor calibration routine. Record
the values for the upscale calibration check for each monitoring channel. If
the proper responses (i.e., +_ 2.5% of span) are not obtained for all of the
monitoring channels, have the operator make the appropriate adjustments before
proceeding with the audit.
28
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5.2.3 Temperature Compensation Check
The GEM-100 monitor output signals vary with stack gas temperature for a
given operating pressure in the duct/stack and for a fixed concentration of
pollutant and/or diluent gas. At higher temperatures, there are fewer
molecules at a given pressure, and hence, there are fewer molecules of the
absorbing gas in the path between the source and the sensor. In addition, the
strength of the absorption lines is somewhat temperature dependent. These
effects are compensated for electronically in the instrument.
Check the monitor's thermistor probe calibration by comparing the monitor
stack temperature readings to actual effluent gas measurements made alongside
the thermistor probe. The temperature measurements should agree within +_ 2%;
otherwise, have the operator adjust the monitor for the proper response. The
internal calibration check should be repeated if adjustments to the temperature
measurement system are made.
5.3 CALIBRATION ERROR TEST
The GEM-100 monitor does not allow injection of calibration gases;
therefore, a calibration error test cannot be performed.
5.4 STRATIFICATION AND RELATIVE ACCURACY TESTS
Before initiating the relative accuracy test, perform a statification test
at the monitor location using the procedures presented in Section 2.3 and
Appendix A of this document. Conduct the relative accuracy test in accordance
with the procedures in Section 2.4 and the Reference Method procedures
delineated in Appendix B of this document. Moisture testing must be conducted
29
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during the relative accuracy tests to facilitate comparison of the wet basis
SM810/CM50 concentration measurements and the dry basis Reference Method
results.
30
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6. ENVIRONMENTAL DATA CORPORATION DIGI SERIES 1400 S02/N0/C02
AUDIT PROCEDURES
6.1 PRINCIPLE OF OPERATION
The EDC DIGI 1400 gas analyzer is an in-situ, single pass, cross-stack,
flue gas monitor designed to measure concentrations of S02, NO, and C02- The
measured gas concentrations are displayed on strip chart recorders on a
real-time basis, in units of concentration. The DIGI 1400 utilizes a
differential absorption analyzer, which operates on the principle that a
specific gas absorbs electromagnetic radiation at specific wavelengths within
the radiation spectrum. For a particular gas, the monitor compares the
absorption of radiation by the effluent stream at a wavelength which is
absorbed by the gas of interest to the absorption at a reference wavelejgth.
The selected measurement and reference wavelengths are very close together,
ensuring that any attenuation due to other gases will be approximately equal at
each wavelength. The effects of such attenuation will therefore tend to cancel
each other, resulting in minimized interference from other gases. The
measurement and reference wavelengths for both NO and SOp are in the
ultraviolet region, while those for C0_ are in the infrared portion of the
spectrum.
The monitoring system utilizes three basic components. The "source" unit,
which generates the ultraviolet radiation, is mounted on one side of the stack.
The "analyzer" unit is mounted directly across from the source unit, and
contains the necessary optical and electronic components to measure the
differential absorption of ultraviolet and infrared light by the effluent at
various wavelengths and to generate an output proportional to the
concentrations of the gases of interest. The "display" unit records the output
data from the analyzer unit and can be located anywhere.
31
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The DIGI 1400 analyzer employs internal sealed gas cells to facilitate a
simulated zero check and upscale calibration check for each monitoring channel.
Some DIGI 1400 monitor installations are equipped with a "zero pipe" (e.g.,
concentric, slotted pipes enclosing the cross-stack optical beam). The zero
pipe can be closed and flooded with ambient air by the purge air blowers to
facilitate a cross-stack zero check.
6.2 INITIAL MONITOR INSPECTION/CALIBRATION CHECK
6.2. 1 Monitor Inspection
Check the strip chart recorders to verify that the outputs of the analyzer
are displayed within the recorder scales. If any of the recorders are
off-scale, ask the source representative (operator) to adjust the ^ata
recorders before continuing.
6.2.2 Internal Calibration Check
Ask the operator to explain the conventions used for interpreting the
strip chart data (e.g., identification of the zero level, scale factor, and/or
maximum data display for each monitoring channel). Also, if the monitor is
interfaced with a computer or other electronic data recorder, ask the operator
to explain fully the method used for averaging and displaying the concentration
measurements, calibration data, and for calculating emission measurements. Ask
the operator for the correct "zero" and upscale calibration check values for
each monitoring channel.
Have the operator perform the daily monitor calibration routine. Record
the values for the zero and upscale checks for each monitoring channel. If the
correct recorder responses (i.e., +_2.5% of span) are not obtained for all of
32
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the monitoring channels, have the operator make the appropriate adjustments
before proceeding with the audit.
If the monitor has a "zero pipe" installed cross-stack, perform a z-ro
check by flooding the zero pipe with air. Record the response of each
monitoring channel for the cross-stack zero check. If adjustments to the
monitor are made as a result of the zero check, the internal calibration check
should be repeated.
6.3 CALIBRATION ERROR TEST
The EDC DIGI Series 1MOO monitor does not allow the injection of
calibration gases, therefore a calibration error test cannot be performed.
6.1 STRATIFICATION AND RELATIVE ACCURACY TESTS
Before initiating the relative accuracy test, perform a statification test
at the monitor location using the procedures presented in Section 2.3 and
Appendix A of this document. Conduct the relative accuracy test in accordance
with the procedures in Section 2.4 and the Reference Method procedures
delineated in Appendix B of this document. Moisture testing must be conducted
during the relative accuracy tests to facilitate comparison of the wet basis
SM810/CM50 concentration measurements and the dry basis Reference Method
results.
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7. QUALITY ASSURANCE PROCEDURES
The EPA Methods applied for relative accuracy tests and for calibration
gas analyses are supplemented by quality assurance activities which entail
assessments of quality control. The quality control assessments and the
criteria that indicate acceptable quality control are described below.
Included with each description .
7. 1 METHOD 3
Quality control of EPA Method 3 is assessed before and during application
in the field; two techniques are employed. The first technique is applied
immediately before the analysis of field samples and entails determinations of
known concentrations of C02 and 02 mixtures contained within aluminized Mylar
bags. These bag samples are prepared at the Entropy laboratory prior to
departure to the field. The gas mixtures used to fill the bags are obtained
from gas cylinders which have concentrations of C02 and 02 (the balance gas
component is nitrogen, N ) selected so as to be consistent with concentrations
ordinarily encountered within the effluent streams of fossil-fuel-fired steam
generators. The cylinder concentrations of C02 and 02 are established by
either: (1) the "Traceability Protocol for Establishing True Concentrations of
Gases Used for Calibration and Audits of Continuous Source Emission Monitors
(Protocol No. D," contained within Quality Assurance Handbook for Air
Pollution Measurements Systems, Volume III, Stationary Source Specific
Methods, EPA-600/4-77-027b, August 1977; or (2) the procedures and criteria
contained within the revisions to Performance Specification 2, proposed in
Federal Register. Vol. 44, No. 197, October 10, 1979, p. 58617. Protocol 1
35
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determinations are conducted by the U.S. EPA, Quality Assurance Division at
their laboratory in Research Triangle Park, North Carolina. All other
determinations are performed by Entropy personnel at the Entropy laboratory.
Two bag samples containing C02 and 02 at two different concentration
levels are determined prior to each series of Method 3 sampling runs
performed. These determinations are conducted by the persons responsible for
analyzing the Method 3 field samples. The criteria for acceptable quality are
results within 0.2% CO and 0.2% 0 of the established concentration values.
Analyses of field samples commence only when quality control is established.
The second technique for assessing quality control is applied during the
Orsat analyses of the individual field samples. The technique, termed the FQ
technique, is based upon the stoichiometries associated with the combustion of
specified fuel types. The F technique has been proposed as a revision to EPA
Method 3: Federal Register. Vol. 17, No. 173, September 7, 1982, pp. 39204 -
39205. The acceptability criterion recognized by Entropy is the same as the
one contained therein.
7.2 METHOD 6
Quality control of the analysis phase of EPA Method 6 is assessed through
the use of "Stationary Source Quality Assurance S02 Reference Standards,"
provided by the Quality Assurance Division (QAD) of the U.S. EPA. Immediately
before titrating S02 samples obtained from source effluents or calibration
gases, two or more S02 Reference Standards are determined in a "blind" fashion
by the person responsible for analyses using the procedures prescribed by the
QAD. The analysis phase of EPA Method 6 is considered to be in a state of
36
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quality control if results of the S02 Reference Standards' determinations are
within +5% of the nominal S02 mass value. The source effluent and calibration
gas S02 samples are analyzed only after quality control has been established.
7.3 METHOD 7
Quality control of the analysis phase of Method 7 is assessed using two
procedures. One procedure is directed toward the linearity of the calibration
curve used for relating absorbance measurements to masses of N02.
Accordingly, the spectrophotometer calibration factor (identified as KC within
Method 7) is first computed. Following this computation, each of the four
absorbance calibration values are multiplied by the KC value to afford the
corresponding N02 masses,which are then compared to the theoretical masses
contained in each sample, i.e., 100 yg, 200 yg, 300 yg, and 400 yg. The
quality of the calibration curve is considered acceptable if not more than one
of the computed N02 masses differs by more than 5 percent relative to the
corresponding theoretical mass.
The other quality control procedure entails the analysis of "Stationary
Source Quality Assurance NOX Reference Standards," provided by the Quality
Assurance Division (QAD) of the U.S. EPA. Two or more of these samples are
analyzed in a "blind" fashion using QAD prescribed procedures. Results within
7 percent of nominal N0_ mass values are considered indicative of acceptable
quality.
Spectrophotometric measurements are not conducted on source effluent or
calibration gas NOX samples until quality control of the Method 7 analysis
phase has been indicated from the results of both procedures described above.
37
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APPENDIX A.
STRATIFICATION TESTING METHODOLOGY FOR
GASEOUS EFFLUENT CONSTITUENTS
-------
STRATIFICATION TESTING METHODOLOGY FOR
GASEOUS EFFLUENT CONSTITUENTS
Stratification is the uneven distribution of the effluent component gases
across the cross section of the ductwork or stack which transports the effluent
to the atmosphere. Stratification of gaseous constituents (S0?, NO , 0?, CO-,
etc.) may occur at or downstream of points along the effluent pathway where the
concentration of one of more constituents of the effluent changes. Thus,
points at which air inleakage occurs, points at which control devices affect
pollutant emission levels (such as at the outlet of flue gas desulfurization
systems), and points at which dissimilar gas streams are combined, may result
in stratification of the effluent stream. Samples obtained at locations where
stratification exists may not provide results which are representative of the
entire effluent stream. It is, in some cases, necessary to conduct a test to
detect and/or quantify the existence of stratification at the existing or
proposed sampling site. The procedures presented in this report are designed
to determine whether effluent stratification is present; this methodology does
not quantify the stratified effluent profile.
Current Performance Specifications for gaseous emission monitors require
that monitors be installed in locations which provide measurements which are
(or can be corrected to be) consistently representative of emissions from the
source. These regulations allow the control agency to require stratification
testing at proposed CEM sampling locations where the location cannot be assumed
to be non-stratified.
Proposed revisions to the Performance Specifications (Jan. 26, 1981,
Federal Register) allow the monitor to be installed at any location provided
A-2
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that the reference method testing to determine the relative accuracy of said
monitors be performed in locations that are representative of the source's
emissions. Stratification testing is an accepted means of demonstrating that
particular sampling locations provide representative emission measurement
results.
Stratification can be measured for either pollutant gases (S0? or NO ) or
diluent gases (0_ or COp) in units of concentration. Alternatively, at steam
generators, stratification may be quantified in units of the applicable
standard (ibs of pollutant per million Btu of heat input). This second
alternative is useful where both the pollutant and diluent monitors are
installed in such a manner as to view the same portion of the effluent, and
where the potential for stratification is due only to air inleakage. Also,
testing to determine the representativeness of a compliance test sampling
location should be conducted in units of the standard.
The only quantitative definition for stratification which is provided in
the existing regulations is contained within Paragraph 3-9, Performance
Specification 2, Appendix B, 40 CFR 60. The definition is as follows:
"3«9 Stratification. A condition identified by a difference in
excess of 10 percent between the average concentration in the duct or
stack and the concentration at any point more than 1 .0 meters from
the duct or stack wall."
Paragraph 4.3 of said specification provides the only guidance regarding
the sampling methodology to be used to determine whether stratification exists;
this paragraph reads:
"4.3. The owner or operator may perform a traverse to characterize
any stratification of effluent gases ... ."
A-3
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Thus, stratification testing is performed by making a series of traverse
measurements across the stack or duct sampling location. To determine whether
or not effluent stratification exists as per the above definition, the average
effluent concentration across the stack or duct must also be known during each
measurement made along the stack traverse. Determining the average effluent
concentration concurrent with each traverse point raeaurement presents some
difficulties. Ideally, concurrent determinations could be made by
simultaneously measuring emissions at several points along the cross section of
the duct or stack. However, this approach is not feasible because of the
extensive manpower and equipment required to measure spatial stratification.
To ensure that the stratification determination is not affected by temporal
changes in the average effluent concentration, a sampling and calculation
method was developed to eliminate the effects of such temporal variations. This
method employs a dual probe system to sample alternately at a traverse point
and a reference point.
Steady operation is preferable for stratification testing, because the
results are unaffected by incremental effluent concentration shifts due to
changing process conditions. If stratification testing is performed on sources
operating under batch process conditions, the testing should be conducted
during segments of steady operation.
EQUIPMENT DESCRIPTION
The sampling apparatus necessary for stratification testing is an
extractive continuous monitoring system comprised of the following: a sample
acquisition and gas conditioning system; SCL, CCU, C^, and/or NO monitors;
strip chart recorders; and an automatic data processor (optional). The sample
A-4
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acquisition system consists of two heated stainless steel sampling probes, and
the monitoring system is capable of alternately measuring the effluent
extracted through each of the two probes. A detailed description of the
extractive monitoring system, along with its calibration and sampling
procedures, is contained in a document prepared for the EPA, SSCD, entitled,
"Transportable Continuous Emission Monitoring System Operational Protocol:
Instrumental Monitoring of S02, NOX, C02, and 02 Effluent Concentrations."
SAMPLING PROCEDURE
To eliminate the effects of temporal variations of the average effluent
concentration, all effluent measurements must be normalizd to a specific point
in time ('t') before the average concentration and percent difference at each
traverse point are calculated; therefore, a dual probe system is used to
measure the effluent emissions. One probe is used as a stationary reference
point placed at the stack or duct centroid during the stratification sampling
period; this probe is used to indicate the temporal change of the effluent
concentrations. The second probe is used for sampling at specified traverse
points determined in accordance with the sampling point criteria of Paragraph
3.3.1 of proposed revisions to Performance Specification 2, Appendix A, 40 CFR
60 (Federal Register, Vol. 44, No. 197, October 10, 1979). The monitoring
system samples at the reference point, traverse point, reference point, etc.,
sequentially throughout the testing period for 3 to 5 minutes at each point.
The monitoring system is calibrated with gases analyzed by the reference
methods immediately before and after the stratification test.
A-5
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CALCULATION PROCEDURE
The derivation of the stratification calculation procedure is based on two
principle assumptions:
1. For each traverse point x, there exists a unique constant of
proportionality between the concentrations of the Reference point and
traverse point, such that:
TX = KXRX [EQ. 1]
where: T = Concentration at traverse point x
K = Proportionality constant for point x
R = Reference point concentration
x = 1, 2, 3. . .
This relationship implies that:
T
K = _L [EQ. 2]
X R
2. All changes in effluent concentration occur in such a manner that the
average concentration for a given measurement time interval is
approximately equal to the average of the concentrations measured
before and after that measurement time interval.
Thus, the average reference concentration at a time when the traverse
point concentration is being measured is equal to the average of the
reference concentrations measured before and after the traverse point
concentration measurement.
Rx ' Rxab = Rxb + Rxa ^Q. 3]
where: R . = Reference concentration before measurement
x of traverse point x
R = Reference concentration after measurement
of traverse point x
In order to compare one traverse point measurement to another on a
consistent basis, the effect of effluent concentration changes with
time must be eliminated. Consequently, all traverse point
measurements must be normalized to some benchmark reference time, t.
A-6
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Txn - KxRt
^xn = normalized value of concentration for point x
K = proportionality constant, defined in EQ. 2
R = Reference concentration at reference time, t
Equation 4 results in the value that would have teen measured for
traverse point x if the reference concentration had been equal to R,.
b
Combining EQ. 2 and EQ. 4 and simplifying the resultant normalized
concentration is:
T
Changes in effluent flow rate or other process operating parameters,
such as failure of a fan, could cause changes in the nature of any
stratification present. This could cause the K values to change,
rendering normalized traverse concentration inaccurate. Again, this
is only a problem if stratification does exist, and the test will
"still detect this stratification, although it will not accurately
quantify it.
The second assumption may provide a more likely reason for inaccurate
indications of the magnitude of effluent stratification. This
assumption is valid only if the sampling time for each traverse point
is small compared to any cyclic changes in the effluent
concentrations, or if the magnitude of these changes in concentration
is small. As changes in concentration become larger, the assumption
that:
becomes more critical. Errors in this assumption become more
pronounced as the measurement time period approaches one-half the
time period of a cyclic concentration change. The most likely result
of such errors is an overestimation of stratification. Thus, the
previously discussed stratification test procedure will err
conservatively, and indications of no stratification can be viewed
with a high level of confidence.
A-7
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STRATIFICATION DATA SHEET
Source and Location
Temporal Change
Reference Probe
Traverse Pro.bc.
7/////////A
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APPENDIX B.
REFERENCE METHOD PROCEDURES -
Reference Method 3
Alternative Method for
Stack Gas Moisture Dsterraination
Reference Method 6
Reference Method 7
-------
VETHOD 3—Ot.i AVALTW ro» PtRnosi DIOXIDI,
OXTIJKV, Excn» AIR, AND DKY Moi KI ut..ia WKIOBT
I. Principle nul Application}
[nation 13 to DA
iv^"/. ii ^ >iry moier mar **imn Tnnnaiion is to cm
made, either an Or^at or a r"> nte l anal> ?>-r may he u.sed
for the anah --is, fnr c\ct ss air nr i minion rate correction
factor determination, an Orsat anabzer must he u^-d.
1.2 Applicability. Tins nn ilioil is api'lii-able for de-
termining O): and o: coiv . Mirations. evcss air, and
dry molecular u» i^lit of 3 Dimple from a gas at ream uf a
fos.-11-fuel coml>ti-lion proces*. The method may also b«
applicable toother process s» here it has been determined
that compounds other than rej,, o». CO, and mtrngen
(Mi) are not present in coi'ccntnuiuiu. sullkieut to
altevt the results.
Other methods, as well .1-5 modifications to the proce-
dure described herein, are <\\M ipplii able (or some or &U
of the above determination*. K\ imples of s|H>citic meth-
ods and modifications include ilia niulti-j^dnt samp-
ling method using an ors-at inaljzcr to tni.il) ze indi-
vidual grab sample obtained at each point. {>) a method
Using CO; or Oj and stoichiunu trie calculation* to deter-
mine dry molecular weight and excess air, ; t> assigning a
value o( 30.0 for dry molevu'ar weight, in lieu of aciual
measurements. for processes I timing natural i^as, coal. or
t'll. Thes« methods and niodilio\iu,ns may be used. l>ilt
are subject to the approval o( Hie Adiinmslrator.
-. .\pparitui
As an alteinalive lo Ihe sampling ipp.u iins ami i>s-
tenis descnN-*! herein, other -ampling svslems (eg,
luiuid displ.icement) may t>c u^rd provided such s>;>teni3
aro capable of obtaining a repn^entafivo sample and
maintaining a constant sainpli'i< rate, and ire otherwise
capable of yielding acceptable re-nlts. I's* of such
<>':>trtm3 is «uhject to the approval of the Administrator.
-I tirab Sampling ( Floury 3 t).
-' 1.1 Prohe. The probe should h« m >d« of stainless
-(••el or noro$ihc.rte gl.ixj tuhniK and should be cf^uippfd
with an in--ta*-k or out sT^ick hltrr to remove paniculate
natter (a plug of s!o»,i wool is -alisfactory for this pur-
!«)>*) Any O'her material inert to Oi, (JOi, CO. and Ni
-uid resistant to temperature at s.\mpluif{ conditions may
Iw used for the probe; examples of such material are
iluiainu'ii, copper, ijuurtz glass ami Teiton.
'2.1 2 Tamp. A one-way .Miucere bull), or equivalent,
13 used to transport the. gas Cample to the analyter,
J.J Iniecrited Sampling (Future 3-2).
22.1 Fiobe A probe such .LS that described m Section
-M I 13 suitable.
i Mention of trade nam-'S or specific products does not
constitute endorsvruent by the Environmental Protec-
tiun Agency.
J 2 2 Condenwr. An air-cooled or water-cooled coo-
oens«r, or othej oocdenser that will not remove Oa,
C Oi, CO, and NI. may be used to remove excess raofetur*
wtuch wcnld InUrfere with the operation of the DumD
and flow met«r.
223 Valve. A nwdle valve is as«d to adjust sample
gas flow rate.
224 Pump. A Irak-frw, dlaphraimi-type pump, or
equivalent, is used to transjwrt sample gas to the flenble
rag Install a small surge, tank between the pump and
jute meier to elijiunate the pulsation eJTcct of the dia-
phragm pump on the rotametcr.
2 2.4 Rate Meter. The rotameler, or equivalent rate
meter, used should be capable of measuring How rate
to within ±2 percent of the selected Bow rale \ flow
rate range of M>0 to 1000 crn'mim is siit-c.-sted.
•228 Flexible Bftc. Any leak-dee ploslic (t f , Tedlar,
»t>lar, Teflon) or plastic-coated aluminum (e g , alumi-
iiiied Mylar) ba«, or equivalent, ha\mg a capacitv
rtinsistrnl with the vlovicd flow rate and time length
cf the test run, may be nscd. A capacity io the range of
M to 90 liters is sufe-sted.
Toleat-check the Lag, connect it tn a wa'er piannmeter
and pressurize the bag to 5 to 10cm H.-O (2 to 4 in. HiO).
Allow to stand for 10 minutes. Any displacement in the
water manometer indicates a leak An alternative leak-
check method Is to pre.s_«uri7e the bag to 5 to 10cm H-O
(2 to 4 in. H-O) and allow to stand overnight. A deflated
ba» indicates a leak.
22.7 Pressure Oa'ige A water-filled U-tuhe manom-
eter, or equivalent, of about 28 cm (12 in ) is used for
the flexible bag leak-check.
2.28 Vacuum Gauge. A mercury manometer or
equivalent, of at least 760 mm Ug (.30 in. Hg) is used for
the sampling train leak-check.
23 Analysis. For Or sat and Fyrite analyter main-
tenan<-e and operation procedures, follow the mstructions
rwommended by the manufacturer, unless otherwise
•pecilied herein.
2 3 1 Dry Molecular Weight Determination. An Onwt
•nalyier or Fyrlle type combustion gas analyzer may be
used.
232 Emission Rate Correction Factor or Eiresa Air
Determination. An Orsat analyter must be used. For
low COi (less than 4 0 percent) or high Oi Cgre*t*r than
150 percent) concentrations, the measuring burette at
the Orsat must have at least 0 1 percent subdivisions.
3. Drj Molteular WtyM Determination
Any of the three samphng and analytical pro* edures
described below may be used for determining the dry
molecular weight.
8.1 Single-Point, Grab Sampling and Analytical
Procedure.
3 1.1 The sampling point in the duct shall either be
at the ctntroid of the cross section or at a point no clo&er
to the walls than 1 00 ID (3 3ft), unj««sotherw1» specified
ty the Administrator.
112 Bet up the equipment as shown In Figure 3-1,
making sure all connections ahead of the analyser are
tight and leak-tree. If an Orsat analyier U used. It a
recommended tbat the analyzer be leaked-checked by
following the procedure In Section 5; however, the leak-
check is optional.
3.1 3 Place the probe in the stack, with the tip of the
probe positioned at the sampling point; purge the sampl-
ing line. Draw a sample into the anal>zer and imme-
diately analyze It for percent COiand percent Ot Deter-
mine the percentage of the gas that Is Ni and CO by
subtracting the sum of the percent CO) and percent Oi
from 100 percent. Calculate the dry molecular weight as
indicated in Section 6.3.
3.1.4 Repeat the sampling, analysis, and calculation
procedures, until the dry molecular weights of any thre«
grab aamplea coffer from their me&a by DO more than
0 3 i 'g-mole (0.3 Iblb-mole). Average these three molec-
ular weighu. and report the result! to the nearest
0 1 g'g-mole Clblb-mole).
3 2 Bmgle-l'omt, Intt«rated Sampling and Analytical
Procedure.
3.2.1 The aampling point in the duct shall be located
as'pecified in section 3.1.1.
3 J 2 Leak-check (optional) the flenble bag as In
Section 2.2 6. Set up the equipment as shown in Figure
3-2. Just pnor ta sampling, leak-check (optional) the
train by placing a vacuum gauge at the condenser inlet,
pulling a vacuum of at least 250 mm Ug (10 in. Hs>.
plugging the ouilet at the quick disconnect, and tin u
lurnmKoff thr pump. The vacuum should remain stable
for at '.fast u i minute. Evacuate the flexible bag Connect
the prolie a .d plaee it m the sta< k. »nh the. tip of the
prol-e posit toned at the sain|-ling point, purge the sampl-
ing line. N>it, coimr< t the l>ag and maWe suic that, all
eon:i*< t.o'i" are tight and leak free.
321 Sample at a constant rate The sampling mil
*hoi.ld be s.nMillaneons with, and for th*» same loldl
length of lime as the pollutant eni'ssiu'i rate determina-
tion C olle* lion of at least 30 liters (1 (K) ft') of sample gas
if reconnie-id*-d. however, smaller volumes niay be
COllert*-(j If desired
3 2 4 Obua-ii one integrated flue gas sample during
efcj h pollutant emission rate determination Within H
hours after the sample is taken, analvzc ift f«r percent
I'Oi and peref :t Oi using either an Orsat analyzer or a
Fynte-type combustion gas ana!3 ter If an Ors-at ana-
lyzer is used, it is recommended that the Orsat leak-
«he
-------
RATE METER
AIR COOLED
CONDENSER
PROBE
FILTER
(GLASS WOOL)
QUICK DISCONNECT
Jl
RIGID CONTAINER
Figure 3-2. Integrated gas-sampling train.
TIME
TRAVERSE
PT.
AVERAGE
Q
1pm
% DEV.a
8*9
(MUSTBE<10%)
Figure 33. Sampling rate data.
Ill-Appendix A-15
B-3
-------
IAS Repeat the analysis and calculation procedural
until the individual dry molecular weights for any three
analyses differ from their mean hy no mor« than 03
g/g-mole (0.3 Ib/lb-mole). Average these three molecular
weights, and report the results to the nearest 0.1 «/g-mol«
(01 Ib/lb-mole).
3 » Multi-Point, Intefralcd Sampling and Analytical
Procedure.
1.3.1 Unless otherwise specified by the Adminis-
trator, a minimum of eight traverse points shall be used
tor circular stack* having diameters less then 0.61 m
(24 In.), a minimum of nine shall be used for rectangu'.ar
stacks having equivalent diameters less than 0.81 m
(24 in.), and a minimum of twelve traverse points shi 11
be u*d for all other caws. The traverse points shall he
located according to Method 1. The use of fewer point*
is subject to approval of the Administrator.
3.3.2 Follow the procedures outlined in Sections 3.!.3
through 3.2.5, eicept for the following- traverse all sam-
pling points and sample at each point for an equal length
of lime. Record sampling data as shown in Figure 3-1
a. Emlaion Kale Corrtditn Factor or Eteat A* Dtttr-
Non.— A Fyrlte-typ« combustion gas analyzer is not
acceptable for eicess air or emission rate correction factor
determination, unless approved by the Administrator.
IX both percent COi and percent Oi are measured, the
analytical results of any of the three procedures given
below may also be used for calculating the dry molecular
•weight.
Each of the three procedures below shall be used o>i'»
•» hen specified in an applicable subpart of the standard*.
The use of these procedures for other purpose* ijjutl lia\ f
specific prior approval of the Administrator.
4.1 Single-Point, Orab Sampling and Anal) I A. J
Procedure.
4.1.1 The sampling point in the duct shall »:thcr be
at the centroid of the cross-section or at a point no C!OMT
to the walls than 1.00m (3.3ft), unless other* is* spett/ied
by the Administrator.
4.1.2 Set up the equipment a." shown in Figure 3-1.
making sure all connections ahead of the analyzes are
tight and leak-tree. Leak-check tho Ors»t anal\,
for percent C'Oi or percent Oj. If MOMS air is desired,
proceed as follows- (1) Immediately analyte the sample
as In Sections 4.1.4 and 4.1.5, for percent COi. Oi, and
CO; (2) determine the percentage of the gas that Is Ni
by subtracting the sum of the percent COj, percent Or,
and percent CO from 100 percent, and (3) calculate
percent excess air as outlined In Section 0 2.
4.1.4 To ensure complete absorption of the COi, Oi
or if applicable, CO, make repeated passes through each
absorbing solution until two consecutive readings are
the same. Several pastes (three or four) slmuld be made
between readings. (If constant readings cannot be
obtained after three consecutive readings, replace the
absorbing solution.)
4.1.5 After the analysis Is completed, leak-check
(mandatory) the Orsat anal) zer oxice again, as described
in Section 5. For the results of the analysis to be valid,
the Orsal analyter must pass this leak test before and
after the analysis. NOTE.— Since tins single-point, gr»h
sampling and analytical procedure is normally conducted
in conjunction with a single-point, grab sampling and
analytical procedure for a pollutant, only ono analyse
is ordinarily conducted. Therefore, great care must be
taken to obtain a valid sample and analysis. Although
in most case* only COi or Oj is required. It is recom-
mended that both COi and Oj be measured. and that
Citation ft in the Bibliography be used to validate the
analytical data.
4.2 Single-Point, Integrated Sampling and Anfll>lie..l
rrocedurc.
4.2.1 The sampling point in the duel sh.i',1 I* IG..U..I
as specified in Section 4.1.1.
4.2.2 Lnik-fhi-ck ImandatorO the iVjiblc h.ig ,i~ m
fVcllon 2 2 e>. Set up the equipment as iho»n ,n Figure
3-2. Jiisl prior to sampling, leaL-clm-k inmndatory the
tram b> placing a vacuum gauge at the oondeibrr inlet
pulling a vacuum of at loast 250 mm llg (10 in Hgi
plugging the outlet at the quick disconnect, and •*<•*
turning off the pump. The vacuum shall remain stable
for at least 0 6 minute. Evacuate iru flexible bag. Con-
nect the probe and plac* it in the stark, with the up of the
probe positioned at the sampling point, purge the w
pling line. Neit, connect the bag and make sure in..:
all connections are tight and leak free.
4.2.3 Sample at a constant rate, or as specified by the
Administrator. The sampling run mnst be simultaneous
with, and for the same total length of time ae, the pollu'-
aut emission rate determination. Collect at least SO
liters (1 00 ft1) of sample gis Smaller volumes may be-
collected, subh-ct to approval of the Administrator.
4.2.4 Obtain one integrated flue gas sample dtinne
each pollutant emission rale determination. Kor emission
rate correction factor deleruinutioti, anahzc the sanipl.*
within 4 hours after it is taken fur peieent CO: or penvri
Oj (as outlined in Sections 4..' 5 throuch 4 2 71. Th-
Orsat anah zer must be lejik-rhecbed i.
or If applicable. CO, make repealed passes tlirnnyn ta- li
absorbing solution until two cimst-cume rea-lmg- an H.e
same Several passes tthree nr four> shonUI N- n.tvl- N-
tween readings Of constant n a three anal).-e.-- difl r,-i nt by volume wiien COi
is lew than or equal to 4 0 (>er\ ent. Average the three ac-
ceptable values of percent t_ Oi and report Ui* result* W
Uie nearest 0 1 percent.
4.2 6.2 For percent O:. repeat the analytical proc«lure
until the results of any thrr« analjMW JinVr by uu more
than (a) 0.3 percent by volume when Oils less than 110
percent or (b) 0.2 percent by volume, when Oj is greater
than 15.0 pen-ent. Aver«<- the three acceptable value." u[
percent Oi and report the results to the nearest 0.1
percent.
4.283 For percent CO. repest the analytical proce-
dure until the results of any three analyses dlller by no
more than 03 percent Average the three acceptable
values of percent CO and report the results to the nearest
0.1 percent.
4.J 7 After the anaKsis is completed, leak-check
fmand!itor>) the Orsat anal> zer ome acaui as described
insertions For the result so'f the anal\s>s in be valid, the
Orsat analyzer must pass this lejk ust before and after
the anal}sis. Note- Although in most instances only COi
or Oi is required, it is recommended that both CO, and
Otbe measured, and that Citation 5 in the Bibliography
b* used to validate the analytical data.
4.3 Mnlti-l'oiiil, Integrated Sampling and Analytical
Procedure.
4.3.1 Both the minimum number of sampling points
and the sampling point location shall be as specmed in
Section 3 3.1 of this method. The use ot fewer points than
specified ie. Jabject to the approval of the Administrator.
4.3.2 Follow the procedures outlined in Sections 4.2 2
through 42.7, eicept for the following: Traverse all
sampling points and sample at each point for an equal
length of time. Record sampling data as shown in Figure
5. Lmk-Clirck Proudvrt for fatal Analyzm
Moving an Orsat analyzer frequently causes It to leak.
Therefore, an Oraat analyzer should be thoroughly leak-
checked on site before the flue gas sample is introduced
into it. The procedure for leak-checking an Orsat analyzer
it:
5.1.1 Bring the liquid level In each pipette up to the
reference mark on the capillary tubing and then close' thn
pipette stopcock.
5.1.2 Raise the leveling bulb sufficiently to bring the
confining liquid meniscus onto the graduated portion of
the burette and then close the manifold stopcock
5.1.3 Record the meniscus position.
5.1.4 Observe the meniscus in the burette and the
liquid level In the pipette for movement over the next 4
minutes.
5.1.5 For the Orsat analyzer to pass the leak-check
two conditions must be met. '
5.1.5.1 The liquid level In each pipette must not fall
b«low the bottom of the capillary tubing during this
4-mi nute i nterval.
5.1.5.2 The meniscus In the burette must not change
by more than 0.2 ml during this4-mlnutelnterval
5.1.« If the analyzer fails the leak-check procedure all
rubber connections and stopcocks should be checked
until the cause of the leak is identified. Leaking stopcocks
must be disassembled, cleaned, and regressed. Leaking
rubber connections must be replaced. After the analyzer
U -eassembled, the teak-check procedure must be
repeated.
8. Calculation*
8.1 Nomenclature.
Mi—Dry molecular weight, g/g-mole flb/lb-mole).
%EA = Percent excess air.
%CO-= Percent COi by volume {dry basis).
%Oj- Percent Oi by volume (dry basis).
<7oCO-Percent CO by volume 'dry basis).
%N;=-Percent Ni by volume (dry basis).
0264 = Ratio of Oi to Niin air, v/v
0.2^1 = Molecular weight of NI or CO, divided by 100
0.320 = .Molecular weight of Oi divided by 100.
0440-Molocular weight of COj divided by 100.
8.2 Percent Eicess Air. Calculate the percent eicess
air (if applicable), by substituting the appropriate
values of peicent O-, CO, and N'i (obtained from Section
4.1 3 or 4 2 4) into Equation 3-1.
I = [rl2
%0,-0.5%CO '
264 %N, ( %0,- 0.5 %'CO).
100
Equation 3-1
NOTE —The equation above assumes that ambient
air Is used as the source of Ot and that the fuel does not
contain appreciable amounts of Ni (as do coke oven or
blast furnace ga-ses). For those cases when appreciable
amounts of Ni are present (coal, oil, and natural gas
do not contain appreciable amounts of N,) or when
oiygcn enrichment is used, alternate methods, subject
to appruval of the Administrator, are required.
6 3 Dry Molecular Weight Use Equation 3-2 to
calculate the dry molecular weight of the stack gas
Equation 3-2
NOTE — The above equation does not consider argon
In air (about 0 9 percent, molecular weight of 37 7).
A negative error of about 04 percent is Introduced.
The tester may opt to include argon in the analysis using
procedures subject to approval of the Administrator.
7. Bittlioyraphy
1. Altshuller. A. P. Storage of Oases and Vapors in
Plastic Bags. International Journal of Air and Water
Pollution. 6.75-81. 1963.
2. Conner, William D. and J. B. Nader. Air Sampling
Plastic Bags. Journal of the American Industrial Hy-
giene Association. IS -291-297. 1964.
3. ^urrell Manual for Oas Analysts, Seventh edition.
Bun-ell Corporation, 2223 Fifth Avenue, Pittsburgh,
Pa. 15219 1S51.
4. Mitchell, W. J. and M. R. Midgett. Field Reliability
of the Orsat Analyzer. Journal of Air Pollution Conuol
Association K 491-495. May 1978.
5. Shigehara, R. T., R. M. Neulicht. and W. S. Smith.
Validating Orsat Analysis Data from Fossil Fuel-Fired
Units. Stack Sampling News. 4(2)21-2«. August, 1978.
Ill-Appendix A-16
B-4
-------
AN ALTERNATIVE METHOD FOR
STACK GAS MOISTURE DETERMINATION
«
Jon Stanley and Peter R. Westlin
Introduction
Reference Method 4 "Determination of Moisture Content
in Stack Gases" in Appendix A of Title 40 CFR Part 60,
Standards of Performance for New Stationary Sources
describes two sampling metnods - a reference method an an
approximation method. The reference method employs
Smith-Greenburg impingers whereas the approximation method
uses midget impingers. A study was conducted to determine
if the approximation method sampling train and procedure
could be modified and be used as an alternative method. In
addition, a similar study was conducted with the Reference
Method 6 train to determine if the procedure could be
modified to simultaneously measure moisture content and S02
concentration .
Test results showed that the midget impinger sampling
train can be used for accurate moisture determination. This
paper describes the two alternative moisture measurement
methods and presents a summary and analysis of results of
the field tests with the methods.
Test Method
1. Apparatus. The sampling equipment is the same as spec-
ified for the moisture approximation method in Reference
Method 4 and in Reference Method 6, except for the
addition of a silica gel trap. (See Figures 1 and 2.)
The silica gel trap is a midget bubbler with a straight
tube.
Emission Measurement Branch, Emission Standards and
Engineering Division, Office of Air Quality Planning and
Standards, Environmental Protection Agency, Research
Triangle Park, North Carolina 27711, August, 1978.
B-5
-------
2. Reagents
For the modified approximation Method 4, add 10 ml
of water to each of the first two impingers and
approximately 15 g of silica gel in the bubbler.
For the modified Reference Method 6 train, add 15
ml of 8 percent isopropanol to the first impinger,
15 ml of 3 percent hydrogen peroxide in the next
two impingers, and approximately 15 g of silica gel
in the final bubbler.
3. Procedure
a. Apply silicone grease as necessary -to the ground
glass fittings of the impinger halves. Wipe any
extra grease from the ball joint fittings and the
outside of the impingers and weigh all the
impingers at one time to the nearest tenth gram.
Record the weight.
b. Assemble the train as shown in Figure 1 or Figure
2.
c. Perform a leak check by disconnecting the first
impinger from the probe and, while blocking the
impinger inlet, activating the pump and opening the
needle valve. An acceptable leak check is achieved
when the rotameter indicates no flow, the dry gas
meter is stationary for one minute, and bubbling in
the impingers is limited to less than one bubble
per second. Release the impinger inlet plug slowly,
turn off the pump, and reconnect the probe.
d. Read and record the dry gas meter volume. Ice down
the impingers and heat the probe as necessary.
Read and record the barometric pressure.
e. Start the sample pump and adjust the sample flow.
Maintain the flow for the modified approximation
Method 4 between 1 and 4 1pm and the flow for
Reference Method 6 at 1 1pm.
f. Continue the sampling for twenty minutes or other
approximate sampling time. (The total moisture
catch must be at least 1.0 gram to maintain
measurement accuracy.) Read and record the dry gas
meter temperature every five minutes during the
sampling run.
g. At the end of the sample run, stop the pump and
record the final dry gas meter volume reading.
Conduct a leak check as specified in Part 3c.
B-6
-------
Heated Probe
Silica Gel Tube
Filter (Glass Wool)
Ice Bath Midget Irapingers
Valve |i|/Rotameter
X sr
i .=.. 4'
V r
Pump Drv Gas Meter
Figure 1. Modified Approximation Method 4 Train
Silica Gel Tube
Valve
!/
Rotameter
Filter (Glass Wool" wLjil
Midget Impingers
Figure 2. Modified Reference Method 6 Triln for
Kofsture Determination
B-7
-------
h. Remove the impingers from the ice bath, cap them
and allow them to warm to ambient temperature.
i. Wipe any excess moisture from the outside of the
impingers and reweigh them in the manner specified
in Part 3a.
Calculations
The following are the calculations used to determine
the moisture content of the stack gas:
(1)
V.,,, = 1.336 x 10~3 W
W G
Where: VWQ = Volume of water vapor condensed, corrected to
standard condtions, scm.
(2)
Where
W = Total weight gain of the condenser and silica
gel trap assembly, g.
m
std
= °-3855 Y
m
m
Dry gas volume measured by meter,
corrected to standard conditons,
d scm.
Y = Meter calibration coefficient,
d imensionless.
P = Absolute meter pressure, in. Hg.
T = Absolute temperature at meter, K.
V = Dry gas volume measured by meter,
dcm.
(3)
Where:
we
x 100
ws
V +
we
std
= Water vapor content in stack gas,
percent.
Discussion and Summary of Test Resu11s
A series of test runs was completed using the
procedures described in the paper on the exhaust of a
gas-fired incinerator. Initial tests were made using trains
based on the condensation principle of Reference Method M,
but using midget irapingers and up to three silica gel traps
in each train. An evaluation of these extra silica gel
-------
traps showed that complete (> 95 percent) moisture
collection was possible with the condenstation train and one
silica gel trap. An error analysis showed that the moisture
collection must be at least 1 g to maintain the absolute
accuracy required of the method (see Recommendations).
Each test run consisted of two identical test trains
(except Run MA-19) operated simultaneously, and the results
were calculated from data collected by each train. The
repeatability of the results was determined by comparing the
results of the two trains run side by side. Table 1 shows a
summary of the test results which includes a brief
description of the trains for each run.
Analysis of the results shows that either modified
moisture method is precise, can be used with no loss of
accuracy, and can be used as an alternative moisture method.
Of the thirteen duplicate runs shown in Table 1, all but one
yielded _+ 0.5 percent absolute agreement or better between
the results of the paired trains.
Error Analysis
The minimum moisture catch should be at least 1 g to
assure accurate results. An error analysis illustrates the
importance of the recommendation. For example, for a
moisture weight gain of 0.60 g, a balance with an accuracy
of _+ 0.05 g could produce results^ between 0.55 and 0.65 g.
For a gas volume of 1.51 x 10~ dscm, these two values
correspond to moisture levels of 4.6 and 5.4 percent,
respectively. Sampling the same stack gas until 1.0 g was
collected would require 2.54 x 10~ dscra of sample gas. A
similar measurement error of _+ 0.05 g in the sample weight
gain would produce moisture levels between 4.8 and 5.2
percent.
References
40 CFR 60, Standards of Peformance for New Stationary
Sources, Federal Register. Vo. 42, No. 160, August 18, 1977.
B-9
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TABLE 1. SUMMARY OF RESULTS
Run
Number
MA-2
Flow
Rate
(1pm)
Moisture
Calculated
from
Train 1
(Percent)
3.6
Moisture
Calculated
from
Train 2
(Percent)
4.1
l)i I ference
Descri ption
of
Tra i its
1 water impinger
3 silica gel traps
MA-6
7.6
8.0
0.4
2 water impingers
2 silica gel traps
CO
I
O
MA-7
MA-8
7.1
5.9
7.2
6.0
0.1
0.1
2 water impingers
2 silica gel traps
2 water impingers
2 silica gel traps
MD-9
6.7
6.6
0.1
2 water impingers
2 silica gel traps
MA-10
6.0
5.9
0.1
2 water impingers
2 silica gel traps
MA-12
MA-14
MA-15
6.4
5.2
4.8
6.3
5.2
4.9
0.1
0.0
0.1
2 water impingers
2 silica gel traps
2 water impingers
2 silica gel traps
2 three percent perox impingc.rs
2 silica gel traps
-------
Run
Number
Flow
Race
(1pm)
TAIlLli I . SUMMAKY Ol-' UIISULTS
(Continued)
Moisture
Calculated
from
Train 1
(Percent)
Moisture
Calculated
from
Train 2
(Percent)
I icrence
Uescr i pLion
ot
Tr.i i us
DO
i
MA-16
MA-17
MA-18
MA-19
6.6
6.9
4.8
6.4
6.5
5.1
4.9
6.6
0.1
1.8
0.1
0.2
2 three percent peroxide
impingers
2 silica gel traps
2 three percent peroxide
impingers
2 silica gel traps
1 80 percent isopropanol
irapinger
2 three percent peroxide
impingers
1 silica gel trap
Train 1
1 80 percent isopropanol
impinger
2 3percent peroxide impingers
1 silica gel trap
Train 2
2 water impingers
2 silica gel traps
-------
MLTHOD 6—DETERMINATION or SVLFI s !>i,jvr E
EMISSIONS FROM BIATIO.\*R\ bunt'ia
1. Principle and Applict/iiiit}
1.1 Principle. A gas sample is extra--lod froui tl e
sampling point in the stack. Tbe sulfuric aud misi
including sulfur tnoxide) and the sulfur dioxide are
separated. Tbe sulfur dioxide fraction is measured by
Viie barium-tborin utratiou method.
1.2 Applicability. This method is applicable for the
determination of sulfur dioxide emissions trom jtationary
sources. The minimum detectable limit o( the method
has been determined to be 3 4 milligrams (mg\ of SOt'm1
(2.12X10-' Ib'fi'). Although no upper lumt has been
established, tests have shown that concentrat'ons as
high as 80.000 mg'm' of SOi can be collected etucl'-ntly
in iwo midget impingers, each containing 15 milliners
of 3 percent hvdrogen peroxide, at a rate of I 0 !pm for
20 minutes. Based on IheorciKal calculations, the upper
concentration limit in a '."O-hter sample is about 93,300
rug ID'.
Possible interft'rents are free ammonia, water-soluble
canons, and fluorides. Tbe cations and fluoridts are
removed by glass wool filters and an isopropanol bubbler.
and he-nee, do not affect the SO; analysis. >A lien samples
are being taltrn from a gas stream with hiph concentra-
tions of very line metallic fumes (such as in mlcu to
control devices), a hich-eincsrncy glass hl>er filter man
be used HI place of the glass wool pin; u e , the one in
the probe^ to remove the cation intcrfuent*.
Free anuuonia uuerft-rrs hy reacting »ith SOj (o form
particulate sulfite and by reacting with the indicator
If free aromoma is prestnt (this can be delrrmined by
knowledge of the process and noticing white nuuculaie
matter in the probe and isoproi>anol bubble:\ alterna-
tive methods, subject to the approval of the AdTum:str»
tor, U.S. Enviroiinn ntal I'roKMion Apency, ar«
re<)mr«0.
2. 4pparotut
11 Sampling. The sampling tnln U shown m Figure
ft-1, and component parts are discussed below. The
teeter has the option of substituting sampling equip-
ment described In Method 8 m Place of the midget im-
pinger equipment of Method 6. However, the Method 8
train must be modified to include a heated niter between
the probe and isoprppanol Impinger, and the operation
of the sampling train and sample analysis must be at
toe flow rates and solution volumes denned in Method 8.
The tester also has the option of determining 3Ui
atznultaneously with paniculate matter and moisture
determinations by (1) replacing the water in a Method 5
Impinger system with 3 percent pehoude solution, or
(2) by replacing the Method 5 water impinfcer system
with a Method 8 i*opropanol-nlter-peroiide system. The
analysis for 8Oi must be consistent with the procedure
In Method 8.
2.1.1 Probe. Borosilicate glass, or stainless steel (other
materials of construction may be used, subject to the
approval of the Administrator), approximately 6-mm
Inside diameter, with a heating system to prevent water
condensation and a filter (either In-slack or heated out-
(tack) to remove paniculate matter, including sulfunc
add mist. A plug of glass wool is a satisfactory filter.
2.1.2 Bubbler and Lmplngers. One midget bubbler,
with medium-coarse glass frit and borosillcate or quartz
(lass wool packed in top (see Figure »-l) to prevent
sulfunc acid mist carryover, and three 30-ml midget
Unpmgers. Tbe bubbler and midget impingers must be
connected in series with leak-free glass connecton. Sili-
eone (Tease may be used, if necessary, to prevent leakage.
At the option of the tester, a midget impinger may be
toad in place of the midget bubbler.
Other collection absorbers and flow rates may be used,
but are subject to the approval of the Administrator.
AJao, collection efficiency must be shown to be at least
99 percent for each test run and must be documented in
the report. If the efficiency is found to be acceptable alter
a aeries of three tests, further documentation is not
required. To conduct the efficiency test, an extra ab-
sorber must be added and analyzed separately. This
mrtra absorber must not contain more than 1 percent of
UM total SOi.
n,» Glass Wool. Boroellfcate or quartz.
S.1.4 Stopcock Oreaae. Acetone-insoluble, heat-
stable slllcone grease may be used, If neceseary
1.1.5 Temperature Oaufe. Dial thermometer, or
equivalent, to measure temperature of gas leafing im-
pinger train to within 1* C (2* F.)
1.1.6 Drying Tub*. Tub* packed with ft- to lo-meab
Indicating type silica (el, or equivalent, to dry the gas
sample and to protect the meter and pump. U the stllac
(el has been used previously, dry at 175* C (350° F) for
2 noun. New silica (el may be used as received. Alterna-
tively, other types of desiccants (equivalent or better)
may be used, subject to approval of the Administrator.
11.7 Value. Needle value, to regulate sample gas flow
rate.
2.1.8 Pump. Leak-free disphragm pomp, or equiv-
alent, to pull gas through the train. Install a small tank
between the pump and rate meter to eliminate the
pulsation effect of the diaphragm pump on the rotameter.
2.1 9 Rate Meter. Rotameter, or equivalent, capable
of measuring flow rate to within 2 percent of the selected
flow rate of about 1000 cc/mln.
2.1.10 Volume Meter. Dry gas meter, sufficiently
accurate to measure the sample volume within 2 percent.
calibrated at the selected flow rate and conditions
actually encountered during sampling, and equipped
with a temperature gauge (dial thermometer, or equiv-
alent) capable ol measuring temperature to within
S°C (5.4-F ).
2.1.11 Barometer. Mercury, amerold, or other barom-
eter capable of measuring atmospheric pressure to within
2.4 mm Hg (0 1 in Hg). In many cases, the barometric
reading ma> be obtained from a nearby national weather
service station, in which case the station value (which
is the absolute barometric pressure) shall be requested
and an adjustment for elevation differences between
the weather station and sampling point shall be applied
at a rate of minus 2.5 mm Hg (O.lin. Hg) p*r30m (100ft)
elevation increase or vice versa for eievation decrease
2.1.12 Vacuum Gauge. At least 760 mm Hg (30 in
Hg) gauge, to be used for leak check of the sampling
train.
2.2 Sample Recovery.
2.2.1 Wash bottles. Polyethylene or (lass, 500 nil.
two.
2.2.2 Storage Bottles. Polyethylene, 100 ml, to store
Impmger samples (one per sample).
2.3 Analysis.
2.3.1 Pipettes. Volumetric type, 5-rnl, 20-ml (one per
sample), and 25-ml sues.
2.3.2 Volumetric Flasks. 100-ml site (one per sample)
and 100-ml site.
2.3.3 Burettes. 5- and 50-ml slies.
2.3.4 Erleniaeyer Flasks 250 ml-elee (one for each
•ample, blank, and standard).
2.3 5 Dropping Bottle 125-ml sin", to add Indicator
2.3 « Graduated Cylinder 100-ml sue.
2.3.7 Spectropbotometer. To measure absorbance at
852 nanometers
3. Recent*
Unless otherwise indicated, all reagents roust conform
to the specifications established by the Committee on
Analytical Reagents of the American Chemical Society
Where such specifications are not available, use the best
available grade.
3.1 Sampling.
3.1.1 Water. Detoniied, distilled to conform to ASTM
specification D1193-74, Type 3. At the option of 'he
analyst, the KMnOt test for oxlditable organic ma'l'-r
may be omitted when high concentrations of orgi>r.u
matter are not expected to be present
312 Isopropanol, 80 percent Mu SO inl of isopropanol
with 20ml of deionited distilled water. Check each let of
Isopropanol for peroxide impurities as follows shak,' 10
ml of isopropanol with 10 ml of freshly prepared 10
percent potassium Iodide solution Prepare a blank by
similarly treating 10 ml of distilled water After 1 minut*.
read the absorhance at 2A2 nanometers on a spectro-
photometer If absorbance exceeds 0 1, reject alcohol for
use
Peroxides may be removed from isopropanol by redis-
tilling or by passage through a column of activated
alumina; however, reagent grade isopropanol witli
suitably low peroxide levels may be obtained from com-
mercial sources. Rejection of contaminated lots may,
therefore, be a more efficient procedure
1.1 3 H>drojten Peroxide, 3 Percent. Dilute 30 percent
hydrogen peroxide 1 9 (v,v) with deionized. distilled
water (30 ml is needed per sample) Prepare fresh dally
314 Potassium Iodide Solution, 10 Percent PlssoUe
10 0 grams KI in deionited. distilled water and dilute to
100 ml Prepare when needed.
1 2 Sample Recovery
121 Water. Deionited, distilled, as in 3 1 I.
122 Isopropanol. 80 Percent Mu SO ml of isopropano'
with 20 ml of deloniied, distilled water
3.3 Analysis
t 3.1 Water. Deiomwd, distilled, as in 3 1.1.
3.3 2 Isopropanol, 100 percent
S3 3 Thorln Indicator l-(o-arsonophenylaioi-2
naphthoM.ft-disulfomc acid, jdi sod mm salt, or equiva-
lent. Dissolve 0.20 g in 100 ml of deionited, distilled
water.
334 Barium Perchlorate Solution, 00100 N Dis-
solve 1 95 g of barium perchlorat* tnhydrate [Ba(ClO.h
IHrO] In 200 ml distilled water and dilute to 1 liu-r with
sopropanol Alternatively. 1 22 g of [BaClr2H-O] nia\
be used instead of the perchlorate St&ndardite as in
Section 5.5.
335 SuUurlc Acid Standard, 0 0100 N. Purchase or
standardize to »0 00112 N against 0 0100 N NaOH which
has previously been standardized against potassium
acid phthalate (primary standard grade)
4. ProcnJurf.
4 1 Sampling.
4 1 1 Preparation of collection train. Measure 15 ml of
80 percent isopropanol into the midget bubbler and 15
ml of 3 portent hydrogen peroxide into each of the first
two midget impmgers Leave the final midget impinger
dry Assemble the train as shown In Figure 6-1 Adjust
probe heater to a temperature sufficient to prevent » ater
condensation. Place crushed tee and water around the
impingers.
4 1 _ Leak-check procedure A 'efllc check prior to th«s
Campling run is optional however, a tenlc chevk after the
sampling mn is rrandstory The !eakist JO seconds. Cirefu'.'y release the
vacuum gauge before releasirg the .lew rr.eter end to
prevent ba»'k Mow of the ir-ip. ^ger fVud
Other leak check procedures '".ay '?* used, subject to
the approval of the Administrator. U 3 Environmental
Protection Agency The procedure used in Method 5 is
not suitable for d.aohragm pump*
413 Sample collection Record the ir.itial dry gas
meter reading and barometric pressure To begin sam-
pling, position the tip of the probe at the ?amphng point,
connect the probe to the bubbler, and start the pump
Adjust the sample now to a constant rate of ap-
proximately 1 0 I'.ter mm as indicated hy the rotameter
NUmtain this constant rate (*10 percent) during the
en'ire sampling run Take readings fdry gas meter.
temperatures at dry gas meter and at impinger outlet
arc! rate meter) at least every 5 minutes Add more ice
during the nin to keep the tempt-rature of the gases
leaving the. last Impinger at yf C '-£? F) or less At the
conclusion of each run, turn off the pump, remove probe
from the stack, and record the V.al readings Conduct a
leak check as m Section 4 1 2 vThis >at cbect is nianda-
tory ) If a leak .5 found, void the te5t run Drain the Ice
hath, and purge the remaining part of the train by draw-
ing c'ean amb'ent air through :he system 'or 15 minutes
at the sampling rat*
Clean ambient air can be prowled by passing air
through a charcoal filter or tS.ro'ix1! an ex'.ra midget
fmpin^er with 15 ml of 3 percent H.Ch The tester may
opt to simply -;?e ambient -i^r, without purification.
42 sample Re< ovry Disconnect the impir.
-------
5.2 Thermometers. Callbrat* against mercnry-tn-
glasa thermometcn.
5.3 Rotameter. The rotameter need not be calibrated
but should be cleaned and maintained according to the
manufacturer's instruction.
5.4 Barometer. Calibrate against a mercury barom-
eter.
5.5 Barium Perchlorate Solution. Standardite the
baritim perchlorate solution against 25 ml at standard
sulfonc acid to which 100 ml o[ 100 percent isopropanol
has b«ea added.
8. Calculation*
Carry out calculation], retaining at least one extra
decimal figure beyond that of the acquired data. Round
off figures after final calculation.
0.1 Nomenclature.
C> —Concentration at sulfur dioxide, dry basis
corrected to standard conditions, mg/dscm
. (lb/d*cf).
.V> Normality of barium perchlorste tltrant,
mllllequivalents/ml.
Pi,,,"Barometric pressure at the exit orifice of the
dry gas meter, mm Hg (in. Eg).
PttdmStandard absolute pressure, 700 mm Hg
CS.fila. Hg).
T." Average dry gas meter absolute temperature,
°K(°R).
T.id - Standard absolute temperature, 293* E
1528° R).
V% >• Volume of sample aliquot titrated, ml.
V.-Dry gas volume as measured by the dry gas
meter, dcm (dcO.
V.(nj)-Dry gw volume measured by the dry gat
meter, corrected to standard conditions,
dscm (dscf).
V—i.— Total volume of solution In which the sulfur
dioxide sample is contained. 100 ml.
Vi«Volume of barium perchlorate tltrant used
for the sample, ml (average of replicate
tltratlons).
Vn^Volume of barium perchlorate tltrant used
for the blank, ml.
Y= Dry gas meter calibration (actor.
32.03= Equivalent weight of sulfur dioxide.
0.2 Dry sample gas volume, corrected to standard
conditions.
"4 t»' _ if v "
' ~
Equation 8-1
where:
K>0 3858 »E/mm Hg for metric unit*.
-17 84 • R.'ln. Hg tor English units.
«J Sulfur dioxide concentration.
•(•id)
where'
Jfi-32.03 mB'meq. for metric oniu.
-7.0BlX10-«lb/rae
-------
METHOD 7—Dm«xn«iTToN or NmooEX OXIDE
EMISSIONS FKCM STmoNiar Souxcis
1. PrindfU mt Apfllataur
1.1 Principle. A grab sample is collected in an evacu-
ated flask containing a dilute sulfurte acid-hydrogen
peroxide absorbing solution, and the nitrogen oxides,
except nitrous oxide, an measured colonmetericsUy
using the pher.oldisulfonlc acid (PDS) procedure.
1.2 Applicability. This method is applicable to the
measurement of nitrogen oxides emitted from stationary
sources. The range 01 the method has been determined
to be 2 to WO milligrams NO, (as NOi) per dry standard
cubic meter, without oaring to dilute tee sample.
2-Xpparorw
XI Sampling (set Figure 7-1). Other grab sampling
systems or equipment, capable of measuring sample
volume to wUhm ±2.0 percent and collecting a sufficient
sample volume to allow analytical reproducibility to
within ±5 percent, will be considered acceptable alter-
natives, subject to approval of the Administrator, U.S.
Environmental Protection Agency. The following
equipment is used in sampling:
2.1.1 Probe. BoroaUlcate glass tubing, sufficiently
heated to prevent water condensation and equipped
with an in-stack or oat-stack niter to'remove particulate
matter (a plug of glass wool is satisfactory for this
purpose). Stainless steel or Teflon ' tubing may also be
used for the probe. Heating Is not necessary if tha probe
remains dry daring the purging period.
I Mention of trade names or specific products does not
constitute endorsement by the Environmental Pro-
tection Agency.
2.1.2 Collection Flask. Two-liter boroslllcat*, round
bottom flask, with short neck and Z4/40 standard taper
opening, Protected against Implosion or breakage.
2.1.3 Flask Valve. T-bore stopcock connected to a
24/40 standard taper joint.
2.1.4 Temperature Qauge. Dial-type thermometer, or
other temperature gaupe, capable of measuring 1° C
(2' F) intervals from -5 to 504 C (25 to 125° F).
2.1 5 Vacuum Line. Tubing capable of withstanding
a vacuum of 75 mm Eg (Jin. Hi?) absolute pressure, with
"T" connection and T-bore stopcock.
2.1.6 Vacuum Gauge. U-tube manometer. 1 meter
(3C in.), with 1-mm (0 1-in.) divisions, or other gauge
capable of measuring pressure to within ±2.5 mm Hg
(010 in. Hg).
2.1.7 Pump. Capable of evacuation the collection
flask to a pressure equal to or less than 75 mm Hg (3 in.
Hg', absolute.
2.1 8 Squeeze Bulb. One-way.
2.1.9 Volumetric Pipette. 25ml.
2.1.10 Stopcock and Ground Joint Grease. A high-
vacuum, high-temperature chlorofluorocarbon grease Is
required. Halocarbon 25-5S has been found to be effective.
2.1.11 Barometer. Mercury, aneroid, or other barom-
eter capable of measuring atmospheric pressure to within
2.5 mm Hg (0.1 in. Hg). In many cases, the barometnc
reading may be obtained from a nearby national weather
service station, in which case the station value (which is
the absolute barometnc pressure) snail be requested and
an adjustment for elevation differences between the
weatht;r ?tat>on and sampling point shall be applied at a
rate of minus 2.b mm Hg <0 1 in Hg) per 30 m (100 ft)
elevat.on increase, or vice versa for elevation decrease.
2.2 Sample Recovery. The following equipment is
required for sample recovery
2.2.1 Graduated C>linder. 50ml with 1-ml divisions.
2.2J; Storage Containers. Leak-free polyethylene
bottles.
2.2.3 Wash Bottle Polyethylene or glass.
2.2.4 Glass SUrring Rod.
2.2.5 Test Paper for Indicating pH. To cover the pH
range of 7 to 14.
2.3 Analysii. For the analysis, the following equip-
ment is needed
2.31 Volumetric Pipettes. Two 1 ml. two 2 ml, one
I ml, one 4 ml, two 10 ml. and one ^5 ml for each sample
and standard
2.3.2 Porcelain Evaporating Dishes. 175- to 2SO-mi
capacity with lip for pouring, one for each sample and
each standard. The Coors No. 45006 (shallow-form, 195
ml) has been found to be satisfactory. Alternatively.
polymethyl pentene beakers (Nalge No. 1203. 150 ml). or
glass beakers (ISO ml) may be used. When glass beakers
are used, etching ot the beakers may cause solid matter
to be present in the analytical steo the solids should be
removed by filtration (see Section 4.3).
2.3.3 Steam Bath Low-temperature ovens or thermo-
statically controlled hot plates kept below 70° C (160° F)
ar» acceptable alternatives.
2.3.4 Dropping Pipette or Dropper. Three required.
23 5 Polyethylene Policeman. One for each sample
and each standard.
2.3 S Graduated Cylinder. 100ml with 1-ml divisions.
2.3.7 Volumetric Flasks. 50 ml (one for each sample),
100 ml (one for each sample and each standard, and one
lor the working standard KNOi solution), and 10*0 mi
(one).
23.8 Spectrophotometer. To measure absorbance at
410 nm.
2.3 9 Graduated Pipette. 10 ml with 0 1-ml divisions.
2310 T«t Paper for Indicating pU To cover the
pH range of 7 to 14.
2.3 11 Analytical Balance. To measure to within 0.1
mg.
PROBE
A
SQUEEZE BULB
FLASK VALVE'
FILTER
GROUND-GLASS SOC
§ NO- 12/5
110 mm
3-WAY STOPCOCK:
T-BORE. § PYREX.
2-mm BORE. 8-mm OO
FLASK
FLASK SHIELD-. ,\
THERMOMETER
GROUND-GLASS CONE.
STANDARD TAPER.
I SLEEVE NO. 24/40
210 mm
GROUND-GLASS
SOCKET. § NO. 12/S
PYREX
FOAM ENCASEMENT
180mm NN , x''^BOILING FLASK-
VjX 2-LITER. ROUND-BOTTOM. SHORT NECK,
WITH I SLEEVE NO. 24/40
Figure 7-1. Sampling train, flask valve, and flask.
B-14
Ill-Appendix A-30
-------
S. Rmytnu
Unless otherwise Indicated, 11 Is Intended that all-
reagents conform to the specifications established by the
Commute* on Analytical Reagents of the American
Chemical Society, where such specifications are avail
•ble; otherwise, use the bet available grade.
8.1 Sampling To prepare ihe absorbing solution,
cautiously add 2 8 ml concentrated HiSO. to I liter of
deioniied, distilled water. Mil well and add 6 ml of 3
percent hydrogen peroxide, freshly prepared from 30
percent hydrogen peroild" solution The absorbing
solution should be used within 1 week of lu preparation.
Do not eipose to extreme heat or direct sunlight.
1.2 Sample Recovery. Two reagents an required (or
simple recovery
3.2.1 Sodium Hydroxide (IN). Dissolve 40 g NaOH
ID delonlied, distilled water and dilute to 1 liter.
3.2.2 Water. Delonlied, distilled to conform to ASTM
ipeclOcatlou D1193-74, Type 3. At the option of the
analyst, the KMNOi test for oxldizable organic matter
may be omitted when high concentrations of organic
matter are not expected to be present.
3.3 Analysis. For the analysis, the following reagents
are required'
3.3.1 Fuming Sulfunc Acid. 15 to 18 percent by weight
tre« sulfur tnonde. HANDLE WITH CAUTION
332 Phenol White solid.
333 Sulfunc Acid Concentrated, 95 percent mini
mum assay HANDLE WITH CAUTION.
334 Potassium Nitrate Dried at 105 to 110° C (220
to Off F) for a minimum of 2 hours Just pnor to prepara-
tion of standard solution.
335 Standard KNOi Solution. Dissolve exactly
2 IU8 K ol dried potassium nitrate (KNOj) in deionired,
distilled water and dilute to 1 liter with deiorurcd,
distilled water m a 1,000-ml volurne'.nc flask.
338 Working Standard KNOi Solution Dilute 10
ml of the standard solution to 100 ml with deionired
distillod water. One mllliliter of the working standard
solution is equivalent to 100 ug nitrogen dioxide (NOi)
2 3.7 Water. Deioruted, distilled as in Section 3 2 '.'
338 Phenoldisulfonic Acid Solution Dissolve 25 g
of pure white phenol in 150 ml concentrated sulfunc
acid on a steam bath Cool, add 75 ml fuming sulfunc
acid, and heat at 100° C (212° F) for 2 hours Store In
a dark, stoppered bottle.
4. Procedure*
4.1 Sampling
411 Pipette 25 ml of absorbing solution into a sample
flask, retaining a sufficient quantity for use in preparing
the calibration standards Insert the flask valve stopper
Into the flask with the valve In the "purge" position
Assemble the sampling train as shown in Figure 7-1
and place the probe at the sampling point Make sure
that all fittings are tight and leak free, and that all
ground glass Joints have been properly greased with a
high-vacuum, high-temperature chlorofliiorocarhon-
based stopcock grease Turn the flask valve and the
pump valvp to their "evacuate" positions Evacuate
the flask to 75 mm Hg (3 in. Hg) absolute pressure, or
less Evacuation to a pressure approaching the vapor
pressure of water at the exLstlnf: temperature is desirable
Turn the pump valve to its "vent" position and turn
off the pump. Check for leakage by observing the ma-
nometer lor any pressure fluctuation (Any variation
greater than 10 mm Hg (04 In Hg) over a per,j,. of
1 minute Is not acceptable, and the flask is not to be
• used until the leakage problem Is corrected. Pressure
in the flask is not to exceed 75 mm Hg (3 in. Hg) absolute
at the time sampling is commenced ) Record the volume
of the flask and valve (Vi). the flajk temperature (T,),
and the barometric pressure. Turn the flask valve
counterclockwise to its "purge" position and do the
same with the pump valve. Purge the probe and the
vacuum tube using the squeete bulb. If condensation
occurs in the probe and the flask valve area, heat the
probe and purge until the condensation disappears
S'ert, turn the pump valve to its "vent" position. Turn
the flask valve chxkrwue to its "evactiate" position and
record the difference in the mercury levels in the manom-
eter. The absolute internal pressure In the flask (P.)
Is equal to the barometric pressure less the manometer
reading Immediately turn the flask valve to the "sam-
ple" position and permit the gas to enter the flask until
pressures in the flafk and sample line (I e.. duct, stack)
are equal. This will usually require about 15 seconds,
a longer period indicates a "plug" in the probe, which
must be corrected betore sampling is continued. After
collecting the sample, turn the flafk valve to its "purge"
position and disconnect the flafk from the sampling
train. Shake the ftafk for at least 5 minutes.
4.1.2 If the gas being sampled contains Insufficient
oxygen for the conversion of NO to NOi (e g.. an ap-
pLicable subpart of the standard may require taking a
sample of a calibration gas mixture of NO in Ni), then
oxygen shall be introduced into the flask to permit this
conversion. Oxygen may be introduced Into the flask
by one of three methods; (I) Before evacuating th»
sampling flask, flush with pure cylinder oiygen. then
evacuate flask to 75 mm Hg (3 in. Hg) absolute pressure
or less; or (2) Inject oxygen into the flask after samplmf.
or (3) terminate sampling with a minimum of 50 nun
Hg (2 In Hg) vacuum remaining in the flask, record
this final pressure, and then vent the flask to the at-
mosphere until the flask pressure Is almost equal u
atmospheric pressure.
4.2 Sample Recovery Let the flask set for a minimum
of 18 hours and then shake the contents for 2 minutes
Connect the flask to a mercury filled U-tube manometer
Open the valve Crom the flask to the manometei and
record the flask temperature (TV), the barometric
pressure, and the difference between the mercury levels
n the manometer The absolute internal pressure in
the flask (Pi) is the barometric pressure less the man-
ometer reading. Transfer the contents of the flask to a
teak-free polyethylene bottle Rinse the flask twice
with 5-ml portions of deionized, distilled water and add
the nnse water to the bottle. Adjust the pH to between
8 and 12 by adding sodium hydroxide (1 N), dropwise
(about 25 to 35 drops) Check the pH by dipping a
atimng rod into the solution and then touching the rod
to the pH test paper Remove as little matejnal as possible
during this step Mark the height of the liquid, level so
that the container can be checked lor leakage after
transport Label the container to clearly identify its
contents Seal the container for shipplr.j
4 J Analysis. Note the level of the liquid tn container
and confirm whether or not any sample was lost during
shipment; note this on the analytical data sheet. If a
noticeable amount of leakage has occurred, either void
the sample or use methods, subject to the approval of
the Administrator, to correct the final results. Immedi-
ately prior to analysis, transfer the contents of the
shipping container to a 50-ml volumetric flask, and
rinse the container twice with 5-ml portions of deionired,
distilled water. Add the nnse water to the flask and
dilute to the mark with deiomted, distilled water; mix
thoroughly. Pipette a 25-ml aliquot Into the procelain
evaporating dish. Return any unused portion of the
sample to the polyethylene storage bottle. Evaporate
the 2o-ml aliquot to dryness on a steam bath and allow
to cool Add 2 ml phenoldisulfonic acid solution to the
dried residue and tnturate thoroughly with a povleth>l-
ene policeman. Make *ure the solution contacts all the
residue Add 1 ml deiontied. distilled water and four
drop? of concentrated sul/unc acid. Heat the solution
on a steam bath for 3 minutes with occasional stimng
Allow the solution to cool, add 20 ml deionited, distilled
water, mix well by stimng. and add concentrated am-
monium hydroxide, dropwise. with constant stimng.
until the pH is 10 (as determined by pH paper). If the
sample contains solids, these must be removed by
filtration (centrifugation is an acceptable alternative,
subject to the approval of the Administrator), as follows
filter through Whatman No 41 filter paper into a 100-ml
volumetric flask, nnse the evaporating dish with three
5-ml portions of deionizeil, distilled »ater, filter these
three nnses Wa5h the filter with at least three 15-m!
portions of deioniied, distilled water Add the filter
washings to the contents of the volumetnc flask and
dilute to the mark with deionued, distilled water If
solids are absent, the solution can tie transferred directly
to the 100-ml volumetnc flask and diluted to the mark
witli deion.ird distilled water. Mix the contents of the
flask thoroughly, and measure the absorbance at the
optimum wavelength used for the standards (Section
5.2 1), using tlie blank solution as a zero reference. Dilute
the sample and the blank with equal volumes of deion-
Ized, distilled water if the absorhance exceeds At. the
absorbance of the 4UO nt N Oi standard (see Section 5.2 2)
4 Col lira/ton
6 1 Flask Volume The volume of the collection flu-;.
flask valve combination must be known pnor to sam-
pling Assemble the flask and flask valve and fill »it>
water, to the stopcock Measure the volume of water t»
±10 ml Record this volume on the flask.
6.2 Spectropholoraeter Calibration.
8.2 1 Optimum Wavelength Determination For botr-
flied and variable wavelength spectrophotoraeters
calibrate against standard certified wavelength of 410
run, every 8 months Alternatively, for variable wave
length spectrophotometers. scan the spectrum betweei.
400 and 416 nm using a 200^ NO: standard solution (see
Section 522) If a peak does not occur, the spectropho-
tometer is probably malfunctioning, and should be re-
paired When a peak is obtained within the 400 to 415 nm
range, the waveleneth at which this peak occurs shall be
the optimum wavelength for the measurement of ab-
sorbance for both the standards and samples.
622 Determination of Spectrophotometer Calihra
tion Factor K, Add 0 0. 1 0. 2 0, 3.0. and 4 0 ml of the
KNOi working standard solution (1 ml-100 rt NOj) to
a series of five porcelain evaporating dishes. To each, add
26 ml of absorbing dilution. 10 ml deionired, distilled
water, and sodium hydroxide (IN), dropwise, until toe
6H Is between » and 12 (abouF^S to 35 drops each)
efinning with the evaporation step, fo'low the analy-
sis procedure of Section 4.3, until the solution has been
transfejred to the 100 ml volumetric flask and diluted to
the mark Measure the absorbance of each solution, at the
optimum wavelength, as determined in Section 621.
This calibration procedure must be repeated on each day
that samples ar» analyred. Calculate the spectrophotom-
eler calibration factor as follows.
K,= 100
S.5 Vacuum Gauge Calibrate mechanical gauges. If
used, against a mercury manometer such as that speci-
fied in 2.1.8.
5.8 Analytical Balance. Calibrate against standard
weights.
A. Calculation*
Carry ont the calculations, retaining at least one extra
decimal figure beyond that of the acquired data. Round
off figures after final calculations.
6.1 Nomenclature.
A — Absorbance of sam pie
C-Concentration of NO, as NO), dry basis, cor-
rected to standard conditions, mg/dscm
(Ib/dscf)
/•-Dilution factor (i e . 23.5, 26/10, etc, required
only if sample dilution was needed to reduce
the absorbance into the range of calibration).
K"e — Spectrophotometer calibration factor
m-Hass of NO, as NOi in gas sample. ia.
Pi" Final absolute pressure o( fiask. mm Hg (in Hg)
Pi-Initial absolute pressure of flask, mm Hg (m
Hg).
Pnd - Standard absolute pressure, 760 mm Hg (29 92 m
He).
TV-Final absolute temperature of flask ,°K CR>
T.-Initial absolute temperature of flask. "K (°R).
r.u- Standard absolute temperature, 2.13° K (5S° R)
V',. -Sample volume at standard conditions (dry
basis), ml
V'/- Volume of flask and valve, ral
V.^Volume of absorbir.tr solution. 25 ml
2 = 50 'i5, the ai;qui>! factor (If other than a 25-ml
aliquot was ased for anaKsis tne corresp^nd-
Ine factor nest he suhsutatod)
8 2 Sample volume, dry basis, corrected to standard
conditions
V —T'« (V,-V ) [~ — — —
"~P.« ' ''IT, T
Equation 7-1
where.
A',-Calibration factor
AI= Absorbance of the 100-Mg NO? standard
Aj = Absorbance of the 200-vg NO, standard
As =» Absorbance of the JdOvig N O; standard
X4-Absorbance of the 40T>-rf v-ri. «ta—<«*H
5.3 Barometer. Calibrate against a mercury bann -
eter.
5.4 Temperature Gauge Calibrate dial them ,
against mercury-in-glass thermometers.
where:
Equation 7-2
°K
A'i — 0.3838 - TT- for metric units
mm Hg
oo
= 17.64 r — rr~ f°r English unit.s
in. Hg
6.3 Total Mg NOi per sample.
Equation 7-3
NOTC.— If other than a 2j-ml aliquot is used for analy-
sis, the factor 2 must be replaced by a corresponding
(actor.
6.4 Sample concentration, dry basis, corrected to
standard conditions.
C=Kt
m
V7.
Equation 7-4
when:
lW — for metric units
/.g/ml
6.243X 10-* '-^— for English units
7.
1. Standard Methods or Chemical Analysis. 6th ed.
New York, D. Vna Nostrand Co., Inc. 1962. Vol. 1.
p. 329-330.
2. Standard Method of Test for Oxides of Nitrogen in
Gaseous Combustion Products (Phenoldisulfonic Acid
Procedure). In 1968 Book of ASTM Standards, Part 2C.
Philadelphia, Pa. 1968. ASTM Designation D-1608-6O,
p. 725-729.
». Jacob, M. B. The Chemical Analysis of Air Pollut-
ants. New York. Interscience Publishers, Inc. 1960.
Vol. 10. p. 351-356.
4. Beatty, R. L., L. B. Berger, and H. H. Schrenk.
Determination of Oxides of Nitrogen by the Phenoldisul-
fonic Acid Method. Bureau of Mines, U.S. Dept. of
Intenor. R. I. 3687. February 1W3.
5. Hamil, H. F. and D. E. Camann. Collaborative
Study of Method for the Determination of Nitrogen
Oxide Emissions from Stationary Sources (Fossil Fuel-
Fired Steam Generators). Southwest Research Institute
report for Environmental Protection Agency. Research
Triangle Park. N.C. October 5, 1973.
6. Hamil, H. F. and R. E. Thomas. Collaborative
Study of Method for the Drtermination of Nitrogen
Oxide Emissions from Stationary Sources (Nitric Acid
Plants). Southwest Research Institute report for En-
vironmental Protection Agency. Research Triangle
Park, N.C. May 8, 1974.
B-15
111- Ape end ix A-
31
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-340/1-83/015
2.
3 RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
Performance Audit Procedures for SC>2, NOX, C02, and
62 Continuous Emission Monitoring Systems
5. REPORT DATE
January 1983
6. PERFORMING ORGANIZATION CODE
'. AUTHOR(S)
Entropy Environmentalists, Inc.
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Entropy Environmentalists, Inc.
P.O. Box 12291
Research Triangle Park, NC 27709
10 PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-01-6317
12. SPONSORING AGENCY NAME AND ADDRESS
OAQPS
Stationary Source Compliance Division
Waterside Mall, 401 M Street, SW
Washington, DC 20460
13. TYPE OF REPORT AND PERIOD COVERED
FINAL - IN-HOUSE
14. SPONSORING AGENCY CODE
EPA/200/04
15. SUPPLEMENTARY NOTES
16. ABSTRACT
This report presents detailed performance audit procedures for a variety of
currently available S02 and NOX GEMS. Specific procedures for conducting
(1) initial monitor inspections/calibration checks, (2) calibration error tests,
(3) stratification tests at monitor sampling locations, and (4) relative accuracy
tests are included for the following monitoring systems: (1) LSI SM810 S02/NO
and CM50 02 monitors, (2) DuPont 460 S02/NOX and Thermox 02 monitors, (3) Contraves
Goerz GEM 100 S02/N0/C02 monitors, and (4) Environmental Data Corporation DIGI
1400 S02/NO/C02 monitors. These procedures may be adapted to other types of
gas emission monitoring systems.
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Air Pollution
Monitoring
Gas Monitoring Systems
Audit Procedures
18. DISTRIBUTION STATEMENT
Release to Public
19. SECURITY CLASS (This Report)
unclassified
21. NO. OF PAGES
76
20. SECURITY CLASS (This page)
unclassified
22. PRICE
EPA Form 2220-1 (Rey. 4-77) PREVIOUS EDITION is OBSOLETE
B-16
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