DAQ-2024-004995

1

DAQC-131-24
Site ID 15792 (B4)

MEMORANDUM

TO: STACK TEST FILE – INTERMOUNTAIN REGIONAL MSW LANDFILL

THROUGH: Harold Burge, Major Source Compliance Section Manager

FROM: Paul Morris, Environmental Scientist

DATE: February 12, 2024

SUBJECT: Source: Landfill NMOC Emissions
Location: 800 South Allen Ranch Road, Fairfield, Utah County, UT
Contact: Brian Alba: 801-930-0984
Tester: Hansen, Allen, and Luce, Inc.
FRS Site ID#: UT0000004904900334
Permit/AO #: Title V Operating Permit 4900334002, dated December 20, 2023
Subject: Review of Pretest Protocol received February 8, 2024

On February 8, 2024, DAQ received a protocol for testing of the Intermountain Regional Landfill located
in Fairfield, Utah County, UT. Testing will be performed on March 11, 2024, to determine compliance
with the New Source emission limits found in Title V Operating Permit Conditions II.B.2.a. and 40 CFR
60 Subpart WWW.

PROTOCOL CONDITIONS:

1. RM 3C used to determine Methane emissions; OK

DEVIATIONS: No deviations were noted.

CONCLUSION: The protocol appears acceptable.

RECOMMENDATION: Send protocol review and test date confirmation notice.

ATTACHMENTS: Stack testing protocol received February 8, 2024.

6 , 3

INTERMOUNTAIN REGIONAL
LANDFILL

NON-ENCLOSED FLARE PERFORMANCE TEST
SITE SPECIFIC TEST PLAN

(HAL Project No.: 373.08.201)

February 2024

INTERMOUNTAIN REGIONAL LANDFILL

NON-ENCLOSED FLARE PERFORMANCE TEST
SITE SPECIFIC TEST PLAN

(HAL Project No.: 373.08.201)

Andrew Alvaro
Environmental Services Director

February 2024

Intermountain Regional Landfill i Performance Test Site Specific Test Plan
TABLE OF CONTENTS

TABLE OF CONTENTS ............................................................................................................. i
CHAPTER 1 - INTRODUCTION ............................................................................................. 1-1
INTRODUCTION ................................................................................................................. 1-1
LANDFILL DESCRIPTION .................................................................................................. 1-1
TESTING LOCATION .......................................................................................................... 1-1
PROPOSED TEST DATES ................................................................................................. 1-1
CONTACTS ......................................................................................................................... 1-1
Facility Representative ..................................................................................................... 1-1
State Representative ........................................................................................................ 1-1
HAL (Testing) Representative .......................................................................................... 1-2
Analytical Laboratory ........................................................................................................ 1-2
CHAPTER 2 – TESTING PROTOCOL ................................................................................... 2-1
GENERAL SAMPLING PROCEDURES NARRATIVE ......................................................... 2-1
EPA METHOD 3C ............................................................................................................... 2-2
CHAPTER 3 – QUALITY ASSURANCE AND QUALITY CONTROL ..................................... 3-1
CALIBRATION .................................................................................................................... 3-1
CYCLONIC AND STRATIFIED FLOW ................................................................................. 3-1
SUMMA® CANISTERS ....................................................................................................... 3-1
REPLICATION .................................................................................................................... 3-1
FIELD DATA ........................................................................................................................ 3-1
LABORATORY ANALYSIS .................................................................................................. 3-2
BACKUP SUMMA® CANISTERS ........................................................................................ 3-2
REFERENCES .......................................................................................................................... 1

LIST OF FIGURES

Figure 1 – IRL Facility Map

APPENDICES

Appendix A – EPA Reference Method 3C

Appendix B – EPA Reference Method 3

Appendix C – EPA Reference Method 1

Appendix D – EPA Reference Method 7E

Intermountain Regional Landfill 1-1 Performance Test Site Specific Test Plan
CHAPTER 1 - INTRODUCTION

INTRODUCTION
Hansen, Allen, & Luce, Inc. (HAL) is planning to conduct the performance test for the non-
enclosed flare associated with the landfill gas collection and control system at the Intermountain
Regional Landfill (IRL). Under the New Source Performance Standards (NSPS) federal
regulations (40 CFR Part 60, Subpart WWW) and National Emissions Standards for Hazardous
Air Pollutants (NESHAP) federal regulations (40 CFR Part 63, Subpart AAAA), IRL is required to
submit a performance test of the non-enclosed flare. The results of this performance test will be
used to demonstrate compliance with the flare operational requirements and establish operational
parameter ranges.

LANDFILL DESCRIPTION
IRL is a Class V landfill operating under a Title V Operating Permit (#4900334002 dated
December 20, 2023) located at 800 South Allen Ranch Road in Fairfield, Utah. The Landfill has
been in operation for 13 years, having first accepted waste in 2012. The active landfill area is
about 72 acres. IRL facilities are shown in Figure 1.

TESTING LOCATION
Intermountain Regional Landfill
800 South Allen Ranch Road
Fairfield, Utah 84013

PROPOSED TEST DATES
HAL anticipates that testing will be performed on March 11th, 2024, and will require one workdays.

CONTACTS
Facility Representative
Brian Alba, Operations Manager
800 South Allen Ranch Road
Fairfield, Utah 84013
801-930-0984
[e-mail]

State Representative
Harold Burge, Major Source Compliance Section Manager
Division of Air Quality, Utah Department of Environmental Quality
150 North 1950 West
Salt Lake City, Utah 84114
385-306-6509
[e-mail]

CHAPTER 1 – INTRODUCTION - CONTINUED
Intermountain Regional Landfill 1-2 Performance Test Site Specific Test Plan
HAL (Testing) Representative
Joshua Hortin, Project Engineer
Hansen, Allen, and Luce, Inc.
859 West South Jordan Parkway Suite 200
South Jordan, Utah 84095
801-566-5599
[e-mail]

Analytical Laboratory
Air Technology Laboratories, Inc.
18501 E Gale Ave, Suite 130
City of Industry, CA 917482655
626-964-4032

Intermountain Regional Landfill 2-1 Performance Test Site Specific Test Plan
CHAPTER 2 – TESTING PROTOCOL

GENERAL SAMPLING PROCEDURES NARRATIVE
HAL will utilize a sampling probe in the common header before the condensate removal system
to collect samples by Environmental Protection Agency (EPA) Method 3 for analysis by EPA
Method 3C.

The landfill gas will be sampled in the common header before the gas moving and condensate
removal equipment using the multi-point integrated sampling procedure. EPA Method 3,
referenced in EPA Method 3C, requires the sampling point in the duct at a minimum of eight
traverse points for equal times (approximately 3 minutes 45 seconds). The traverse points will be
located with the assistance of EPA Method 1.

The sampling train will be purged of five sampling tubing volumes and screened using a portable
landfill gas analyzer to verify the absence of ambient air by comparison to the quality control
criteria of EPA Method 25C and/or stratified flow by EPA Method 7E. Specifically, gas from each
probe location on two perpendicular transects through the header will be screened for methane,
carbon dioxide, oxygen, and nitrogen content. While there are no landfill gas content quality
control criteria for the performance test, the absence of ambient air will be confirmed by the
general quality control criteria of EPA Method 25C/3C, which requires oxygen content in gas
samples analyzed by the laboratory to be less than 5 percent, or nitrogen to be less than 20
percent, or the nitrogen/oxygen ratio to be over 3.71 for landfills receiving less than 20 inches of
annual precipitation for the past 3 years. If these field quality control criteria are not met, then HAL
personnel will remove, check, and reinstall the sampling probe and verify that there is no
malfunction in the gas collection system, and the header will be rescreened. This process will be
repeated until the absence of ambient air is verified.

After purging and verifying the absence of stratified flow and system malfunction, the probe will
be attached to an evacuated Summa® canister and sampling train. The sampling train will be
purged with helium prior to sample collection as a precaution against cross-canister
contamination. A measured volume of landfill gas will then be drawn into the canister at a rate of
approximately 0.133 liters per minute or less. Flow into the canister will be regulated with a needle
valve and the flow rate will be monitored using a calibrated rotameter. The sampling probe will be
adjusted at regular time intervals to eliminate the effects of undetected stratified flow.

The leak-check protocol for the Summa® canisters is to record the vacuum just prior and
immediately after sampling at each location, and to record a final vacuum just prior to shipping
the Summa® canisters back to the laboratory. The laboratory will measure the vacuum readings
upon receipt and compare the readings to the pre-shipment readings to ensure the absence of
leaks.

Summa® canisters have a volume of six liters at sea level; however, the effective canister volume
at the elevation of the Landfill is reduced to approximately five liters. In addition, the canisters will
be preloaded by the laboratory with one liter of helium, which reduces the effective volume of the
canister to approximately four liters. Helium is added to reduce the potential explosivity hazard of
the methane containing canisters, which eliminates costly hazardous shipment procedures that
would otherwise be required. Three Summa® cannisters will be used to collect samples from the
header.

Intermountain Regional Landfill 2-2 Performance Test Site Specific Test Plan
Three 30-minute samples will be collected from the main header into three Summa® canisters.
Each Summa® canister will be analyzed by the laboratory for methane in triplicate.

After samples have been collected the probe will be removed, and the sampling port will be
closed.

EPA METHOD 3C
EPA Method 3C is used to measure the concentration of methane, nitrogen, and oxygen in the
Summa® canister composite samples. The samples will be analyzed in triplicate by the analytical
laboratory. The nitrogen and oxygen contents will be noted for comparison to the quality control
requirements of EPA Method 25C.

Intermountain Regional Landfill 3-1 Performance Test Site Specific Test Plan
CHAPTER 3 – QUALITY ASSURANCE AND QUALITY
CONTROL

CALIBRATION
The landfill gas analyzer will be calibrated on the sampling day for methane and oxygen. The
calibration results will be shown in the test report.

CYCLONIC AND STRATIFIED FLOW
Gas from each probe location on two perpendicular transects through the header will be screened
for methane according to EPA Method 7E. The methane measurements at each transect location
should be within 5-10% of the mean of methane measurements at all locations. The method
contains sampling instructions if stratified flow is found.

The absence of cyclonic flow by EPA Method 1 does not need to be verified because the
conditions specified in EPA Method 1 which may induce cyclonic flow do not exist in the IRL
header.

SUMMA® CANISTERS
Summa® canisters are certified clean before shipment due to their reusable nature. The
laboratory documents cannister cleanliness and conducts regular blank test audits of the process.
The canisters are shipped under approximately -30 inches of mercury (Hg) vacuum, which
corresponds to about -25 to -26.5 inches Hg at the IRL altitude.

Upon receipt of the canisters and just prior to sampling, the vacuum in the cannisters will be
checked and recorded to ensure the absence of leaks in transit. The cannister vacuum will be
checked and recorded again after each sample collection, and just prior to shipping back to the
laboratory. The laboratory will check the vacuum upon receipt and compare the readings to the
pre-shipment readings to ensure the absence of leaks in transit.

The Summa® canisters will be shipped on the same day of sampling if possible, or the next
morning if not. If the Summa® canisters are shipped the next morning, the vacuums will be
rechecked and re-recorded prior to shipping.

All data will be recorded on field data sheets with the cannister serial number and on the chain-
of-custody form.

REPLICATION
The three specified samples will serve as replicates for precision, therefore a fourth replicate will
be collected as a backup sample but not analyzed unless one of the other three cannisters is
found to leak in transit.

FIELD DATA
HAL will record the Summa canister vacuum readings just before and just after sample collection,
the Summa canister serial number, and the sampling start and end times on the field forms. The

Intermountain Regional Landfill 3-2 Performance Test Site Specific Test Plan
ambient air temperature and general weather conditions will be noted throughout each sampling
day. The collected samples will be handled according to best practice general sampling and
chain-of-custody procedures and specific laboratory instructions, if any.

LABORATORY ANALYSIS
The Quality Assurance and Quality Control (QA/QC) procedures of EPA Methods 3C will be
observed by the laboratory for instrument operation, calibration, and calibration verification. The
QA/QC data will be included in the test report.

BACKUP SUMMA® CANISTERS
The laboratory will ship one extra Summa® canister than required for this performance test. If a
cannister is found to have a leak during the pre-sampling vacuum check, one replacement
cannister will be used.

Intermountain Regional Landfill F-1 Performance Test Site Specific Test Plan
REFERENCES

Environmental Protection Agency. (2023). Method 1-Sample and Velocity Traverses for
Stationary Sources. Retrieved January 31, 2024 from
https://www.epa.gov/system/files/documents/2023-
09/2023%20Final%20MS%20%20Method%201_0.pdf.

Environmental Protection Agency. (2017). Method 3-Gas Analysis for the Determination of Dry
Molecular Weight. Retrieved January 31, 2024 from
https://www.epa.gov/sites/default/files/2017-08/documents/method_3.pdf.

Environmental Protection Agency. (2023). Method 3C-Determination of Carbon Dioxide,
Methane, Nitrogen, and Oxygen from Stationary Sources. Retrieved November 7, 2023
from https://www.epa.gov/sites/default/files/2017-08/documents/method_3c.pdf.

Environmental Protection Agency. (2018). Method 7E-Determination of Nitrogen Oxides
Emissions from Stationary Sources (Instrumental Analyzer Procedure). Retrieved January
31, 2024 from https://www.epa.gov/sites/default/files/2018-
05/documents/method_7e_0.pdf.

Environmental Protection Agency. (2023). Method 25C-Determination of Nonmethane Organic
Compounds (NMOC) in Landfill Gases. Retrieved November 7, 2023 from
https://www.epa.gov/sites/default/files/2017-08/documents/method_25c.pdf.

Intermountain Regional Landfill F-1 Performance Test Site Specific Test Plan
FIGURES

Intermountain Regional Landfill
Legend
Access Roads
LGCS Pipes
Active Area
ImperviousSurface
PropertyBoundary05001,000250 Feet
¦

Leachate Collection Sump
Maintenance Shed
Office
Scalehouse and Scales Fueling Station
Flare
All waste unloading occurs within theactive, lined area of the landfill.
Property Size: 363 Acres
FIGURE
1Facilities Map
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Intermountain Regional Landfill F-2 Performance Test Site Specific Test Plan
APPENDIX A

Method 3C 8/2/2017

1

While we have taken steps to ensure the accuracy of this Internet version of the document, it is not the
official version. The most recent edits to this method were published here:
https://www.gpo.gov/fdsys/pkg/FR-2016-08-30/pdf/2016-19642.pdf. To see a complete version
including any recent edits, visit: https://www.ecfr.gov/cgi-bin/ECFR?page=browse and search under
Title 40, Protection of Environment.
METHOD 3C—DETERMINATION OF CARBON DIOXIDE, METHANE, NITROGEN, AND OXYGEN
FROM STATIONARY SOURCES
1. Applicability and Principle
1.1 Applicability. This method applies to the analysis of carbon dioxide (CO2), methane (CH4),
nitrogen (N2), and oxygen (O2) in samples from municipal solid waste landfills and other sources
when specified in an applicable subpart.
1.2 Principle. A portion of the sample is injected into a gas chromatograph (GC) and the CO2,
CH4, N2, and O2 concentrations are determined by using a thermal conductivity detector (TCD)
and integrator.
2. Range and Sensitivity
2.1 Range. The range of this method depends upon the concentration of samples. The analytical
range of TCD's is generally between approximately 10 ppmv and the upper percent range.
2.2 Sensitivity. The sensitivity limit for a compound is defined as the minimum detectable
concentration of that compound, or the concentration that produces a signal-to-noise ratio of
three to one. For CO2, CH4, N2, and O2, the sensitivity limit is in the low ppmv range.
3. Interferences
Since the TCD exhibits universal response and detects all gas components except the carrier,
interferences may occur. Choosing the appropriate GC or shifting the retention times by
changing the column flow rate may help to eliminate resolution interferences.
To assure consistent detector response, helium is used to prepare calibration gases. Frequent
exposure to samples or carrier gas containing oxygen may gradually destroy filaments.
4. Apparatus
4.1 Gas Chromatograph. GC having at least the following components:
4.1.1 Separation Column. Appropriate column(s) to resolve CO2, CH4, N2, O2, and other gas
components that may be present in the sample.
4.1.2 Sample Loop. Teflon or stainless steel tubing of the appropriate diameter.
Method 3C 8/2/2017

2

NOTE: Mention of trade names or specific products does not constitute endorsement or
recommendation by the U. S. Environmental Protection Agency.
4.1.3 Conditioning System. To maintain the column and sample loop at constant temperature.
4.1.4 Thermal Conductivity Detector.
4.2 Recorder. Recorder with linear strip chart. Electronic integrator (optional) is recommended.
4.3 Teflon Tubing. Diameter and length determined by connection requirements of cylinder
regulators and the GC.
4.4 Regulators. To control gas cylinder pressures and flow rates.
4.5 Adsorption Tubes. Applicable traps to remove any O2 from the carrier gas.
5. Reagents
5.1 Calibration and Linearity Gases. Standard cylinder gas mixtures for each compound of
interest with at least three concentration levels spanning the range of suspected sample
concentrations. The calibration gases shall be prepared in helium.
5.2 Carrier Gas. Helium, high-purity.
6. Analysis
6.1 Sample Collection. Use the sample collection procedures described in Methods 3 or 25C to
collect a sample of landfill gas (LFG).
6.2 Preparation of GC. Before putting the GC analyzer into routine operation, optimize the
operational conditions according to the manufacturer's specifications to provide good resolution
and minimum analysis time. Establish the appropriate carrier gas flow and set the detector
sample and reference cell flow rates at exactly the same levels. Adjust the column and detector
temperatures to the recommended levels. Allow sufficient time for temperature stabilization.
This may typically require 1 hour for each change in temperature.
6.3 Analyzer Linearity Check and Calibration. Perform this test before sample analysis.
6.3.1 Using the gas mixtures in section 5.1, verify the detector linearity over the range of
suspected sample concentrations with at least three concentrations per compound of interest.
This initial check may also serve as the initial instrument calibration.
6.3.2 You may extend the use of the analyzer calibration by performing a single-point calibration
verification. Calibration verifications shall be performed by triplicate injections of a single-point
standard gas. The concentration of the single-point calibration must either be at the midpoint of
Method 3C 8/2/2017

3

the calibration curve or at approximately the source emission concentration measured during
operation of the analyzer.
6.3.3 Triplicate injections must agree within 5 percent of their mean, and the average calibration
verification point must agree within 10 percent of the initial calibration response factor. If these
calibration verification criteria are not met, the initial calibration described in section 6.3.1, using
at least three concentrations, must be repeated before analysis of samples can continue.
6.3.4 For each instrument calibration, record the carrier and detector flow rates, detector filament
and block temperatures, attenuation factor, injection time, chart speed, sample loop volume, and
component concentrations.
6.3.5 Plot a linear regression of the standard concentrations versus area values to obtain the
response factor of each compound. Alternatively, response factors of uncorrected component
concentrations (wet basis) may be generated using instrumental integration.
NOTE: Peak height may be used instead of peak area throughout this method.
6.4 Sample Analysis. Purge the sample loop with sample, and allow to come to atmospheric
pressure before each injection. Analyze each sample in duplicate, and calculate the average
sample area (A). The results are acceptable when the peak areas for two consecutive injections
agree within 5 percent of their average. If they do not agree, run additional samples until
consistent area data are obtained. Determine the tank sample concentrations according to section
7.2.
7. Calculations
Carry out calculations retaining at least one extra decimal figure beyond that of the acquired
data. Round off results only after the final calculation.
7.1 Nomenclature.
Bw = Moisture content in the sample, fraction.
CN2 = Measured N2 concentration (by Method 3C), fraction.
CN2Corr = Measured N2 concentration corrected only for dilution, fraction.
Ct = Calculated NMOC concentration, ppmv C equivalent.
Ctm = Measured NMOC concentration, ppmv C equivalent.
Pb = Barometric pressure, mm Hg.
Pt = Gas sample tank pressure after sampling, but before pressurizing, mm Hg absolute.
Ptf = Final gas sample tank pressure after pressurizing, mm Hg absolute.
Pti = Gas sample tank pressure after evacuation, mm Hg absolute.
Method 3C 8/2/2017

4

Pw = Vapor pressure of H2O (from Table 25C-1), mm Hg.
r = Total number of analyzer injections of sample tank during analysis (where j = injection
number, 1 . . . r).
R = Mean calibration response factor for specific sample component, area/ppm.
Tt = Sample tank temperature at completion of sampling, °K.
Tti = Sample tank temperature before sampling, °K.
Ttf = Sample tank temperature after pressurizing, °K.
7.2 Concentration of Sample Components. Calculate C for each compound using Equations 3C-1
and 3C-2. Use the temperature and barometric pressure at the sampling site to calculate Bw. If
the sample was diluted with helium using the procedures in Method 25C, use Equation 3C-3 to
calculate the concentration.

7.3 Measured N2 Concentration Correction. Calculate the reported N2 correction for Method
25-C using Eq. 3C-4. If oxygen is determined in place of N2, substitute the oxygen concentration
for the nitrogen concentration in the equation.

8. Bibliography
1. McNair, H.M., and E.J. Bonnelli. Basic Gas Chromatography. Consolidated Printers,
Berkeley, CA. 1969.

Intermountain Regional Landfill F-3 Performance Test Site Specific Test Plan
APPENDIX B

Method 3 8/3/2017

1

While we have taken steps to ensure the accuracy of this Internet version of the document, it is not the
official version. To see a complete version including any recent edits, visit:
https://www.ecfr.gov/cgi-bin/ECFR?page=browse and search under Title 40, Protection of
Environment.
METHOD 3 - GAS ANALYSIS FOR THE DETERMINATION OF DRY MOLECULAR
WEIGHT
Note: This method does not include all of the specifications (e.g., equipment and supplies) and
procedures (e.g., sampling) essential to its performance. Some material is incorporated by
reference from other methods in this part. Therefore, to obtain reliable results, persons using this
method should also have a thorough knowledge of Method 1.
1.0 Scope and Application
1.1 Analytes.
Analytes CAS No. Sensitivity
Oxygen (O2) 7782–44–7 2,000 ppmv.
Nitrogen (N2) 7727–37–9 N/A.
Carbon dioxide (CO2) 124–38–9 2,000 ppmv.
Carbon monoxide (CO) 630–08–0 N/A.
1.2 Applicability. This method is applicable for the determination of CO2 and O2 concentrations
and dry molecular weight of a sample from an effluent gas stream of a fossil-fuel combustion
process or other process.
1.3 Other methods, as well as modifications to the procedure described herein, are also
applicable for all of the above determinations. Examples of specific methods and modifications
include: (1) A multi-point grab sampling method using an Orsat analyzer to analyze the
individual grab sample obtained at each point; (2) a method for measuring either CO2 or O2 and
using stoichiometric calculations to determine dry molecular weight; and (3) assigning a value of
30.0 for dry molecular weight, in lieu of actual measurements, for processes burning natural gas,
coal, or oil. These methods and modifications may be used, but are subject to the approval of the
Administrator. The method may also be applicable to other processes where it has been
determined that compounds other than CO2, O2, carbon monoxide (CO), and nitrogen (N2) are
not present in concentrations sufficient to affect the results.
1.4 Data Quality Objectives. Adherence to the requirements of this method will enhance the
quality of the data obtained from air pollutant sampling methods.
2.0 Summary of Method
Method 3 8/3/2017

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2.1 A gas sample is extracted from a stack by one of the following methods: (1) single-point,
grab sampling; (2) single-point, integrated sampling; or (3) multi-point, integrated sampling. The
gas sample is analyzed for percent CO2 and percent O2. For dry molecular weight determination,
either an Orsat or a Fyrite analyzer may be used for the analysis.
3.0 Definitions[Reserved]
4.0 Interferences
4.1 Several compounds can interfere, to varying degrees, with the results of Orsat or Fyrite
analyses. Compounds that interfere with CO2 concentration measurement include acid gases
(e.g., sulfur dioxide, hydrogen chloride); compounds that interfere with O2 concentration
measurement include unsaturated hydrocarbons (e.g., acetone, acetylene), nitrous oxide, and
ammonia. Ammonia reacts chemically with the O2 absorbing solution, and when present in the
effluent gas stream must be removed before analysis.
5.0 Safety
5.1 Disclaimer. This method may involve hazardous materials, operations, and equipment. This
test method may not address all of the safety problems associated with its use. It is the
responsibility of the user of this test method to establish appropriate safety and health practices
and determine the applicability of regulatory limitations prior to performing this test method.
5.2 Corrosive Reagents.
5.2.1 A typical Orsat analyzer requires four reagents: a gas-confining solution, CO2 absorbent,
O2 absorbent, and CO absorbent. These reagents may contain potassium hydroxide, sodium
hydroxide, cuprous chloride, cuprous sulfate, alkaline pyrogallic acid, and/or chromous chloride.
Follow manufacturer's operating instructions and observe all warning labels for reagent use.
5.2.2 A typical Fyrite analyzer contains zinc chloride, hydrochloric acid, and either potassium
hydroxide or chromous chloride. Follow manufacturer's operating instructions and observe all
warning labels for reagent use.
6.0 Equipment and Supplies
Note: As an alternative to the sampling apparatus and systems described herein, other sampling
systems (e.g., liquid displacement) may be used, provided such systems are capable of obtaining
a representative sample and maintaining a constant sampling rate, and are, otherwise, capable of
yielding acceptable results. Use of such systems is subject to the approval of the Administrator.
6.1 Grab Sampling (See Figure 3–1).
6.1.1 Probe. Stainless steel or borosilicate glass tubing equipped with an in-stack or out-of-stack
filter to remove particulate matter (a plug of glass wool is satisfactory for this purpose). Any
other materials, resistant to temperature at sampling conditions and inert to all components of the
Method 3 8/3/2017

3

gas stream, may be used for the probe. Examples of such materials may include aluminum,
copper, quartz glass, and Teflon.
6.1.2 Pump. A one-way squeeze bulb, or equivalent, to transport the gas sample to the analyzer.
6.2 Integrated Sampling (Figure 3–2).
6.2.1 Probe. Same as in Section 6.1.1.
6.2.2 Condenser. An air-cooled or water-cooled condenser, or other condenser no greater than
250 ml that will not remove O2, CO2, CO, and N2, to remove excess moisture which would
interfere with the operation of the pump and flowmeter.
6.2.3 Valve. A needle valve, to adjust sample gas flow rate.
6.2.4 Pump. A leak-free, diaphragm-type pump, or equivalent, to transport sample gas to the
flexible bag. Install a small surge tank between the pump and rate meter to eliminate the
pulsation effect of the diaphragm pump on the rate meter.
6.2.5 Rate Meter. A rotameter, or equivalent, capable of measuring flow rate to ±2 percent of the
selected flow rate. A flow rate range of 500 to 1000 ml/min is suggested.
6.2.6 Flexible Bag. Any leak-free plastic (e.g., Tedlar, Mylar, Teflon) or plastic-coated
aluminum (e.g., aluminized Mylar) bag, or equivalent, having a capacity consistent with the
selected flow rate and duration of the test run. A capacity in the range of 55 to 90 liters (1.9 to
3.2 ft3) is suggested. To leak-check the bag, connect it to a water manometer, and pressurize the
bag to 5 to 10 cm H2O (2 to 4 in. H2O). Allow to stand for 10 minutes. Any displacement in the
water manometer indicates a leak. An alternative leak-check method is to pressurize the bag to 5
to 10 cm (2 to 4 in.) H2O and allow to stand overnight. A deflated bag indicates a leak.
6.2.7 Pressure Gauge. A water-filled U-tube manometer, or equivalent, of about 30 cm (12 in.),
for the flexible bag leak-check.
6.2.8 Vacuum Gauge. A mercury manometer, or equivalent, of at least 760 mm (30 in.) Hg, for
the sampling train leak-check.
6.3 Analysis. An Orsat or Fyrite type combustion gas analyzer.
7.0 Reagents and Standards
7.1 Reagents. As specified by the Orsat or Fyrite-type combustion analyzer manufacturer.
7.2 Standards. Two standard gas mixtures, traceable to National Institute of Standards and
Technology (NIST) standards, to be used in auditing the accuracy of the analyzer and the
analyzer operator technique:
Method 3 8/3/2017

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7.2.1. Gas cylinder containing 2 to 4 percent O2 and 14 to 18 percent CO2.
7.2.2. Gas cylinder containing 2 to 4 percent CO2 and about 15 percent O2.
8.0 Sample Collection, Preservation, Storage, and Transport
8.1 Single Point, Grab Sampling Procedure.
8.1.1 The sampling point in the duct shall either be at the centroid of the cross section or at a
point no closer to the walls than 1.0 m (3.3 ft), unless otherwise specified by the Administrator.
8.1.2 Set up the equipment as shown in Figure 3–1, making sure all connections ahead of the
analyzer are tight. If an Orsat analyzer is used, it is recommended that the analyzer be leak-
checked by following the procedure in Section 11.5; however, the leak-check is optional.
8.1.3 Place the probe in the stack, with the tip of the probe positioned at the sampling point.
Purge the sampling line long enough to allow at least five exchanges. Draw a sample into the
analyzer, and immediately analyze it for percent CO2 and percent O2 according to Section 11.2.
8.2 Single-Point, Integrated Sampling Procedure.
8.2.1 The sampling point in the duct shall be located as specified in Section 8.1.1.
8.2.2 Leak-check (optional) the flexible bag as in Section 6.2.6. Set up the equipment as shown
in Figure 3–2. Just before sampling, leak-check (optional) the train by placing a vacuum gauge at
the condenser inlet, pulling a vacuum of at least 250 mm Hg (10 in. Hg), plugging the outlet at
the quick disconnect, and then turning off the pump. The vacuum should remain stable for at
least 0.5 minute. Evacuate the flexible bag. Connect the probe, and place it in the stack, with the
tip of the probe positioned at the sampling point. Purge the sampling line. Next, connect the bag,
and make sure that all connections are tight.
8.2.3 Sample Collection. Sample at a constant rate (±10 percent). The sampling run should be
simultaneous with, and for the same total length of time as, the pollutant emission rate
determination. Collection of at least 28 liters (1.0 ft3) of sample gas is recommended; however,
smaller volumes may be collected, if desired.
8.2.4 Obtain one integrated flue gas sample during each pollutant emission rate determination.
Within 8 hours after the sample is taken, analyze it for percent CO2 and percent O2 using either
an Orsat analyzer or a Fyrite type combustion gas analyzer according to Section 11.3.
Note: When using an Orsat analyzer, periodic Fyrite readings may be taken to verify/confirm the
results obtained from the Orsat.
8.3 Multi-Point, Integrated Sampling Procedure.
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8.3.1 Unless otherwise specified in an applicable regulation, or by the Administrator, a
minimum of eight traverse points shall be used for circular stacks having diameters less than 0.61
m (24 in.), a minimum of nine shall be used for rectangular stacks having equivalent diameters
less than 0.61 m (24 in.), and a minimum of 12 traverse points shall be used for all other cases.
The traverse points shall be located according to Method 1.
8.3.2 Follow the procedures outlined in Sections 8.2.2 through 8.2.4, except 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 3–3.
9.0 Quality Control
Section Quality control measure Effect
8.2 Use of Fyrite to confirm
Orsat results
Ensures the accurate measurement of CO2 and O2.
10.1 Periodic audit of analyzer and
operator technique
Ensures that the analyzer is operating properly and that
the operator performs the sampling procedure correctly
and accurately.
11.3 Replicable analyses of
integrated samples
Minimizes experimental error.
10.0 Calibration and Standardization
10.1 Analyzer. The analyzer and analyzer operator's technique should be audited periodically as
follows: take a sample from a manifold containing a known mixture of CO2 and O2, and analyze
according to the procedure in Section 11.3. Repeat this procedure until the measured
concentration of three consecutive samples agrees with the stated value ±0.5 percent. If
necessary, take corrective action, as specified in the analyzer users manual.
10.2 Rotameter. The rotameter need not be calibrated, but should be cleaned and maintained
according to the manufacturer's instruction.
11.0 Analytical Procedure
11.1 Maintenance. The Orsat or Fyrite-type analyzer should be maintained and operated
according to the manufacturers specifications.
11.2 Grab Sample Analysis. Use either an Orsat analyzer or a Fyrite-type combustion gas
analyzer to measure O2 and CO2 concentration for dry molecular weight determination, using
procedures as specified in the analyzer user's manual. If an Orsat analyzer is used, it is
recommended that the Orsat leak-check, described in Section 11.5, be performed before this
determination; however, the check is optional. Calculate the dry molecular weight as indicated in
Section 12.0. Repeat the sampling, analysis, and calculation procedures until the dry molecular
weights of any three grab samples differ from their mean by no more than 0.3 g/g-mole (0.3
Method 3 8/3/2017

6

lb/lb-mole). Average these three molecular weights, and report the results to the nearest 0.1 g/g-
mole (0.1 lb/lb-mole).
11.3 Integrated Sample Analysis. Use either an Orsat analyzer or a Fyrite-type combustion gas
analyzer to measure O2 and CO2 concentration for dry molecular weight determination, using
procedures as specified in the analyzer user's manual. If an Orsat analyzer is used, it is
recommended that the Orsat leak-check, described in Section 11.5, be performed before this
determination; however, the check is optional. Calculate the dry molecular weight as indicated in
Section 12.0. Repeat the analysis and calculation procedures until the individual dry molecular
weights for any three analyses differ from their mean by no more than 0.3 g/g-mole (0.3 lb/lb-
mole). Average these three molecular weights, and report the results to the nearest 0.1 g/g-mole
(0.1 lb/lb-mole).
11.4 Standardization. A periodic check of the reagents and of operator technique should be
conducted at least once every three series of test runs as outlined in Section 10.1.
11.5 Leak-Check Procedure for Orsat Analyzer. Moving an Orsat analyzer frequently causes it
to leak. Therefore, an Orsat 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 is as follows:
11.5.1 Bring the liquid level in each pipette up to the reference mark on the capillary tubing, and
then close the pipette stopcock.
11.5.2 Raise the leveling bulb sufficiently to bring the confining liquid meniscus onto the
graduated portion of the burette, and then close the manifold stopcock.
11.5.3 Record the meniscus position.
11.5.4 Observe the meniscus in the burette and the liquid level in the pipette for movement over
the next 4 minutes.
11.5.5 For the Orsat analyzer to pass the leak-check, two conditions must be met:
11.5.5.1 The liquid level in each pipette must not fall below the bottom of the capillary tubing
during this 4-minute interval.
11.5.5.2 The meniscus in the burette must not change by more than 0.2 ml during this 4-minute
interval.
11.5.6 If the analyzer fails the leak-check procedure, check all rubber connections and stopcocks
to determine whether they might be the cause of the leak. Disassemble, clean, and regrease any
leaking stopcocks. Replace leaking rubber connections. After the analyzer is reassembled, repeat
the leak-check procedure.
12.0 Calculations and Data Analysis
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12.1 Nomenclature.
Md = Dry molecular weight, g/g-mole (lb/lb-mole).
%CO2 = Percent CO2 by volume, dry basis.
%O2 = Percent O2 by volume, dry basis.
%CO = Percent CO by volume, dry basis.
%N2 = Percent N2 by volume, dry basis.
0.280 = Molecular weight of N2 or CO, divided by 100.
0.320 = Molecular weight of O2 divided by 100.
0.440 = Molecular weight of CO2 divided by 100.
12.2 Nitrogen, Carbon Monoxide Concentration. Determine the percentage of the gas that is N2
and CO by subtracting the sum of the percent CO2 and percent O2 from 100 percent.
12.3 Dry Molecular Weight. Use Equation 3–1 to calculate the dry molecular weight of the stack
gas.

Note: The above Equation 3–1 does not consider the effect on calculated dry molecular weight of
argon in the effluent gas. The concentration of argon, with a molecular weight of 39.9, in
ambient air is about 0.9 percent. A negative error of approximately 0.4 percent is introduced. The
tester may choose to include argon in the analysis using procedures subject to approval of the
Administrator.
13.0 Method Performance[Reserved]
14.0 Pollution Prevention[Reserved]
15.0 Waste Management[Reserved]
16.0 References
1. Altshuller, A.P. Storage of Gases and Vapors in Plastic Bags. International Journal of Air and
Water Pollution. 6 :75–81. 1963.
2. Conner, William D. and J.S. Nader. Air Sampling with Plastic Bags. Journal of the American
Industrial Hygiene Association. 25 :291–297. 1964.
Method 3 8/3/2017

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3. Burrell Manual for Gas Analysts, Seventh edition. Burrell Corporation, 2223 Fifth Avenue,
Pittsburgh, PA. 15219. 1951.
4. Mitchell, W.J. and M.R. Midgett. Field Reliability of the Orsat Analyzer. Journal of Air
Pollution Control Association. 26 :491–495. May 1976.
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):21–26. August 1976.
17.0 Tables, Diagrams, Flowcharts, and Validation Data

Method 3 8/3/2017

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Time Traverse point Q (liter/min) % Deviationa

Average
a % Dev.=[(Q−Qavg)/Qavg]×100 (Must be ≤±10%)
Figure 3–3. Sampling Rate Data

Intermountain Regional Landfill F-4 Performance Test Site Specific Test Plan
APPENDIX C

Method 1 05/30/2023
1

While we have taken steps to ensure the accuracy of this Internet version of the document, it is not the
official version. The most recent edits to this method were published here:
https://www.gpo.gov/fdsys/pkg/FR-2016-08-30/pdf/2016-19642.pdf. To see a complete version
including any recent edits, visit: https://www.ecfr.gov/cgi-bin/ECFR?page=browse and search under
Title 40, Protection of Environment.
Method 1— Sample and Velocity Traverses for Stationary Sources
NOTE: This method does not include all of the specifications (e.g., equipment and supplies) and
procedures (e.g., sampling) essential to its performance. Some material is incorporated by reference from
other methods in this part. Therefore, to obtain reliable results, persons using this method should have a
thorough knowledge of at least the following additional test method: Method 2.
1.0 Scope and Application
1.1 Measured Parameters. The purpose of the method is to provide guidance for the selection of sampling
ports and traverse points at which sampling for air pollutants will be performed pursuant to regulations set
forth in this part. Two procedures are presented: a simplified procedure, and an alternative procedure (see
section 11.5). The magnitude of cyclonic flow of effluent gas in a stack or duct is the only parameter
quantitatively measured in the simplified procedure.
1.2 Applicability. This method is applicable to gas streams flowing in ducts, stacks, and flues. This
method cannot be used when: (1) the flow is cyclonic or swirling; or (2) a stack is smaller than 0.30 meter
(12 in.) in diameter, or 0.071 m2 (113 in.2) in cross-sectional area. The simplified procedure cannot be
used when the measurement site is less than two stack or duct diameters downstream or less than a half
diameter upstream from a flow disturbance.
1.3 Data Quality Objectives. Adherence to the requirements of this method will enhance the quality of the
data obtained from air pollutant sampling methods.
NOTE: The requirements of this method must be considered before construction of a new facility from
which emissions are to be measured; failure to do so may require subsequent alterations to the stack or
deviation from the standard procedure. Cases involving variants are subject to approval by the
Administrator.
2.0 Summary of Method
2.1 This method is designed to aid in the representative measurement of pollutant emissions and/or total
volumetric flow rate from a stationary source. A measurement site where the effluent stream is flowing in
a known direction is selected, and the cross-section of the stack is divided into a number of equal areas.
Traverse points are then located within each of these equal areas.
3.0 Definitions [Reserved]
4.0 Interferences [Reserved]
5.0 Safety
5.1 Disclaimer. This method may involve hazardous materials, operations, and equipment. This test method
may not address all of the safety problems associated with its use. It is the responsibility of theuser of this
test method to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to performing this test method.

Method 1 05/30/2023
2

6.0 Equipment and Supplies.
6.1 Apparatus. The apparatus described below is required only when utilizing the alternative site selection
procedure described in section 11.5 of this method.
6.1.1 Directional Probe. Any directional probe, such as United Sensor Type DA Three-Dimensional
Directional Probe, capable of measuring both the pitch and yaw angles of gas flows is acceptable. Before
using the probe, assign an identification number to the directional probe, and permanently mark or
engrave the number on the body of the probe. The pressure holes of directional probes are susceptible to
plugging when used in particulate-laden gas streams. Therefore, a procedure for cleaning the pressure
holes by “back-purging” with pressurized air is required.
6.1.2 Differential Pressure Gauges. Inclined manometers, U-tube manometers, or other differential
pressure gauges (e.g., magnehelic gauges) that meet the specifications described in Method 2, section 6.2.
NOTE: If the differential pressure gauge produces both negative and positive readings, then both negative
and positive pressure readings shall be calibrated at a minimum of three points as specified in Method 2,
section 6.2.
7.0 Reagents and Standards [Reserved]
8.0 Sample Collection, Preservation, Storage, and Transport [Reserved]
9.0 Quality Control [Reserved]
10.0 Calibration and Standardization [Reserved]
11.0 Procedure
11.1 Selection of Measurement Site.
11.1.1 Sampling and/or velocity measurements are performed at a site located at least eight stack or duct
diameters downstream and two diameters upstream from any flow disturbance such as a bend, expansion,
or contraction in the stack, or from a visible flame. If necessary, an alternative location may be selected,
at a position at least two stack or duct diameters downstream and a half diameter upstream from any flow
disturbance.
11.1.2 An alternative procedure is available for determining the acceptability of a measurement location
not meeting the criteria above. This procedure described in section 11.5 allows for the determination of
gas flow angles at the sampling points and comparison of the measured results with acceptability criteria.
11.2 Determining the Number of Traverse Points.
11.2.1 Particulate Traverses.
11.2.1.1 When the eight- and two-diameter criterion can be met, the minimum number of traverse points
shall be: (1) twelve, for circular or rectangular stacks with diameters (or equivalent diameters) greater
than 0.61 meter (24 in.); (2) eight, for circular stacks with diameters between 0.30 and 0.61 meter (12 and
24 in.); and (3) nine, for rectangular stacks with equivalent diameters between 0.30 and 0.61 meter (12
and 24 in.).

Method 1 05/30/2023
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11.2.1.2 When the eight- and two-diameter criterion cannot be met, the minimum number of traverse
points is determined from Figure 1-1. Before referring to the figure, however, determine the distances
from the measurement site to the nearest upstream and downstream disturbances, and divide each distance
by the stack diameter or equivalent diameter, to determine the distance in terms of the number of duct
diameters. Then, determine from Figure 1-1 the minimum number of traverse points that corresponds: (1)
to the number of duct diameters upstream; and (2) to the number of diameters downstream. Select the
higher of the two minimum numbers of traverse points, or a greater value, so that for circular stacks the
number is a multiple of 4, and for rectangular stacks, the number is one of those shown in Table 1-1.
11.2.2 Velocity (Non-Particulate) Traverses. When velocity or volumetric flow rate is to be determined
(but not particulate matter), the same procedure as that used for particulate traverses (Section 11.2.1) is
followed, except that Figure 1-2 may be used instead of Figure 1-1.
11.3 Cross-Sectional Layout and Location of Traverse Points.
11.3.1 Circular Stacks.
11.3.1.1 Locate the traverse points on two perpendicular diameters according to Table 1-2 and the
example shown in Figure 1-3. Any equation (see examples in References 2 and 3 in section 16.0) that
gives the same values as those in Table 1-2 may be used in lieu of Table 1-2.
11.3.1.2 For particulate traverses, one of the diameters must coincide with the plane containing the
greatest expected concentration variation (e.g., after bends); one diameter shall be congruent to the
direction of the bend. This requirement becomes less critical as the distance from the disturbance
increases; therefore, other diameter locations may be used, subject to the approval of the Administrator.
11.3.1.3 In addition, for elliptical stacks having unequal perpendicular diameters, separate traverse points
shall be calculated and located along each diameter. To determine the cross-sectional area of the elliptical
stack, use the following equation:
Square Area = D1 × D2 × 0.7854
Where: D1= Stack diameter 1
D2= Stack diameter 2
11.3.1.4 In addition, for stacks having diameters greater than 0.61 m (24 in.), no traverse points shall be
within 2.5 centimeters (1.00 in.) of the stack walls; and for stack diameters equal to or less than 0.61 m
(24 in.), no traverse points shall be located within 1.3 cm (0.50 in.) of the stack walls. To meet these
criteria, observe the procedures given below.
11.3.2 Stacks With Diameters Greater Than 0.61 m (24 in.).
11.3.2.1 When any of the traverse points as located in section 11.3.1 fall within 2.5 cm (1.0 in.) of the
stack walls, relocate them away from the stack walls to: (1) a distance of 2.5 cm (1.0 in.); or (2) a distance
equal to the nozzle inside diameter, whichever is larger. These relocated traverse points (on each end of a
diameter) shall be the “adjusted” traverse points.
11.3.2.2 Whenever two successive traverse points are combined to form a single adjusted traverse point,
treat the adjusted point as two separate traverse points, both in the sampling and/or velocity measurement
procedure, and in recording of the data.
11.3.3 Stacks With Diameters Equal To or Less Than 0.61 m (24 in.). Follow the procedure in section
11.3.1.1, noting only that any “adjusted” points should be relocated away from the stack walls to: (1) a
distance of 1.3 cm (0.50 in.); or (2) a distance equal to the nozzle inside diameter, whichever is larger.

Method 1 05/30/2023
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11.3.4 Rectangular Stacks.
11.3.4.1 Determine the number of traverse points as explained in sections 11.1 and 11.2 of this method.
From Table 1-1, determine the grid configuration. Divide the stack cross-section into as many equal
rectangular elemental areas as traverse points, and then locate a traverse point at the centroid of each
equal area according to the example in Figure 1-4.
11.3.4.2 To use more than the minimum number of traverse points, expand the “minimum number of
traverse points” matrix (see Table 1-1) by adding the extra traverse points along one or the other or both
legs of the matrix; the final matrix need not be balanced. For example, if a 4 × 3 “minimum number of
points” matrix were expanded to 36 points, the final matrix could be 9 × 4 or 12 × 3, and would not
necessarily have to be 6 × 6. After constructing the final matrix, divide the stack cross-section into as
many equal rectangular, elemental areas as traverse points, and locate a traverse point at the centroid of
each equal area.
11.3.4.3 The situation of traverse points being too close to the stack walls is not expected to arise with
rectangular stacks. If this problem should ever arise, the Administrator must be contacted for resolution of
the matter.
11.4 Verification of Absence of Cyclonic Flow.
11.4.1 In most stationary sources, the direction of stack gas flow is essentially parallel to the stack walls.
However, cyclonic flow may exist (1) after such devices as cyclones and inertial demisters following
venturi scrubbers, or (2) in stacks having tangential inlets or other duct configurations which tend to
induce swirling; in these instances, the presence or absence of cyclonic flow at the sampling location must
be determined. The following techniques are acceptable for this determination.
11.4.2 Level and zero the manometer. Connect a Type S pitot tube to the manometer and leak-check
system. Position the Type S pitot tube at each traverse point, in succession, so that the planes of the face
openings of the pitot tube are perpendicular to the stack cross-sectional plane; when the Type S pitot tube
is in this position, it is at “0° reference.” Note the differential pressure (Δp) reading at each traverse point.
If a null (zero) pitot reading is obtained at 0° reference at a given traverse point, an acceptable flow
condition exists at that point. If the pitot reading is not zero at 0° reference, rotate the pitot tube (up to
±90° yaw angle), until a null reading is obtained. Carefully determine and record the value of the rotation
angle (α) to the nearest degree. After the null technique has been applied at each traverse point, calculate
the average of the absolute values of α; assign α values of 0° to those points for which no rotation was
required, and include these in the overall average. If the average value of α is greater than 20°, the overall
flow condition in the stack is unacceptable, and alternative methodology, subject to the approval of the
Administrator, must be used to perform accurate sample and velocity traverses.
11.5 Alternative Measurement Site Selection Procedure. The alternative site selection procedure may
be used to determine the rotation angles in lieu of the procedure outlined in section 11.4 of this
method.
11.5.1 This alternative procedure applies to sources where measurement locations are less than 2
equivalent or duct diameters downstream or less than one-half duct diameter upstream from a flow
disturbance. The alternative should be limited to ducts larger than 24 in. in diameter where blockage and
wall effects are minimal. A directional flow-sensing probe is used to measure pitch and yaw angles of the
gas flow at 40 or more traverse points; the resultant angle is calculated and compared with acceptable
criteria for mean and standard deviation.

Method 1 05/30/2023
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NOTE: Both the pitch and yaw angles are measured from a line passing through the traverse point and
parallel to the stack axis. The pitch angle is the angle of the gas flow component in the plane that
INCLUDES the traverse line and is parallel to the stack axis. The yaw angle is the angle of the gas flow
component in the plane PERPENDICULAR to the traverse line at the traverse point and is measured from
the line passing through the traverse point and parallel to the stack axis.
11.5.2 Traverse Points. Use a minimum of 40 traverse points for circular ducts and 42 points for
rectangular ducts for the gas flow angle determinations. Follow the procedure outlined in section 11.3 and
Table 1-1 or 1-2 of this method for the location and layout of the traverse points. If the alternative
measurement location is determined to be acceptable according to the criteria in this alternative
procedure, use the same minimum of 40 traverse points for circular ducts and 42 points for rectangular
ducts that were used in the alternative measurement procedure for future sampling and velocity
measurements.
11.5.3 Measurement Procedure.
11.5.3.1 Prepare the directional probe and differential pressure gauges as recommended by the
manufacturer. Capillary tubing or surge tanks may be used to dampen pressure fluctuations. It is
recommended, but not required, that a pretest leak check be conducted. To perform a leak check,
pressurize or use suction on the impact opening until a reading of at least 7.6 cm (3 in.) H2O registers on
the differential pressure gauge, then plug the impact opening. The pressure of a leak-free system will
remain stable for at least 15 seconds.
11.5.3.2 Level and zero the manometers. Since the manometer level and zero may drift because of
vibrations and temperature changes, periodically check the level and zero during the traverse.
11.5.3.3 Position the probe at the appropriate locations in the gas stream and rotate until zero deflection
is indicated for the yaw angle pressure gauge. Determine and record the yaw angle. Record the pressure
gauge readings for the pitch angle and determine the pitch angle from the calibration curve. Repeat this
procedure for each traverse point. Complete a “back-purge” of the pressure lines and the impact openings
prior to measurements of each traverse point.
11.5.3.4 A post-test check as described in section 11.5.3.1 is required. If the criteria for a leak-free system
are not met, repair the equipment, and repeat the flow angle measurements.
11.5.4 Calibration. Use a flow system as described in sections 10.1.2.1 and 10.1.2.2 of Method 2. In
addition, the flow system shall have the capacity to generate two test-section velocities: one between 365
and 730 m/min (1,200 and 2,400 ft/min) and one between 730 and 1,100 m/min (2,400 and 3,600 ft/min).
11.5.4.1 Cut two entry ports in the test section. The axes through the entry ports shall be perpendicular to
each other and intersect in the centroid of the test section. The ports should be elongated slots parallel to
the axis of the test section and of sufficient length to allow measurement of pitch angles while
maintaining the pitot head position at the test-section centroid. To facilitate alignment of the directional
probe during calibration, the test section should be constructed of plexiglass or some other transparent
material. All calibration measurements should be made at the same point in the test section, preferably at
the centroid of the test section.
11.5.4.2 To ensure that the gas flow is parallel to the central axis of the test section, follow the procedure
outlined in section 11.4 for cyclonic flow determination to measure the gas flow angles at the centroid of
the test section from two test ports located 90° apart. The gas flow angle measured in each port must be
±2° of 0°. Straightening vanes should be installed, if necessary, to meet this criterion.
11.5.4.3 Pitch Angle Calibration. Perform a calibration traverse according to the manufacturer's
recommended protocol in 5° increments for angles from −60° to +60° at one velocity in each of the two
ranges specified above. Average the pressure ratio values obtained for each angle in the two flow ranges,
and plot a calibration curve with the average values of the pressure ratio (or other suitable measurement
Method 1 05/30/2023
6

factor as recommended by the manufacturer) versus the pitch angle. Draw a smooth line through the data
points. Plot also the data values for each traverse point. Determine the differences between the measured
data values and the angle from the calibration curve at the same pressure ratio. The difference at each
comparison must be within 2° for angles between 0° and 40° and within 3° for angles between 40° and
60°.
11.5.4.4 Yaw Angle Calibration. Mark the three-dimensional probe to allow the determination of the yaw
position of the probe. This is usually a line extending the length of the probe and aligned with the impact
opening. To determine the accuracy of measurements of the yaw angle, only the zero or null position need
be calibrated as follows: Place the directional probe in the test section, and rotate the probe until the zero
position is found. With a protractor or other angle measuring device, measure the angle indicated by the
yaw angle indicator on the three-dimensional probe. This should be within 2° of 0°. Repeat this
measurement for any other points along the length of the pitot where yaw angle measurements could be
read in order to account for variations in the pitot markings used to indicate pitot head positions.
12.0 Data Analysis and Calculations
12.1 Nomenclature.
L = length.
n = total number of traverse points.
Pi = pitch angle at traverse point i, degree.
Ravg = average resultant angle, degree.
Ri = resultant angle at traverse point i, degree.
Sd = standard deviation, degree.
W = width.
Yi = yaw angle at traverse point i, degree.

12.2 For a rectangular cross section, an equivalent diameter (De) shall be calculated using the
following equation, to determine the upstream and downstream distances: 𝐷𝐷𝑒𝑒=2𝐿𝐿(𝑊𝑊)𝐿𝐿+𝑊𝑊 Eq. 1-1
12.3 If use of the alternative site selection procedure (Section 11.5 of this method) is required, perform
the following calculations using the equations below: the resultant angle at each traverse point, the
average resultant angle, and the standard deviation. Complete the calculations retaining at least one extra
significant figure beyond that of the acquired data. Round the values after the final calculations.
12.3.1 Calculate the resultant angle at each traverse point: 𝑅𝑅𝑖𝑖=𝑎𝑎𝑎𝑎𝑐𝑐 𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐[(𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑌𝑌𝑖𝑖)(𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑃𝑃𝑖𝑖)] Eq. 1-2
12.3.2 Calculate the average resultant for the measurements: 𝑅𝑅𝑎𝑎𝑎𝑎𝑎𝑎=∑𝑅𝑅𝑖𝑖 𝑛𝑛 Eq. 1-3

Method 1 05/30/2023
7

12.3.3 Calculate the standard deviations:
𝑆𝑆𝑑𝑑=�∑�𝑅𝑅𝑖𝑖−𝑅𝑅𝑎𝑎𝑎𝑎𝑎𝑎�2𝑛𝑛𝑖𝑖=1 (𝑛𝑛−1) Eq. 1-4

12.3.4 Acceptability Criteria. The measurement location is acceptable if Ravg ≤20° and Sd ≤10°.

13.0 Method Performance [Reserved]
14.0 Pollution Prevention [Reserved]
15.0 Waste Management [Reserved]
16.0 References

1. Determining Dust Concentration in a Gas Stream, ASME Performance Test Code No. 27. New York.
1957.

2. DeVorkin, Howard, et al. Air Pollution Source Testing Manual. Air Pollution Control District. Los
Angeles, CA. November 1963.

3. Methods for Determining of Velocity, Volume, Dust and Mist Content of Gases. Western Precipitation
Division of Joy Manufacturing Co. Los Angeles, CA. Bulletin WP-50. 1968.

4. Standard Method for Sampling Stacks for Particulate Matter. In: 1971 Book of ASTM Standards, Part
23. ASTM Designation D 2928-71. Philadelphia, PA. 1971.Hanson, H.A., et al. Particulate Sampling
Strategies for Large Power Plants Including Nonuniform Flow. USEPA, ORD, ESRL, Research Triangle
Park, NC. EPA-600/2-76-170. June 1976.

5. Entropy Environmentalists, Inc. Determination of the Optimum Number of Sampling Points: An
Analysis of Method 1 Criteria. Environmental Protection Agency. Research Triangle Park, NC. EPA
Contract No. 68-01-3172, Task 7.

6. Hanson, H.A., R.J. Davini, J.K. Morgan, and A.A. Iversen. Particulate Sampling Strategies for Large
Power Plants Including Nonuniform Flow. USEPA, Research Triangle Park, NC. Publication No. EPA-
600/2-76-170. June 1976. 350 pp.

7. Brooks, E.F., and R.L. Williams. Flow and Gas Sampling Manual. U.S. Environmental Protection
Agency. Research Triangle Park, NC. Publication No. EPA-600/2-76-203. July 1976. 93 pp.

8. Entropy Environmentalists, Inc. Traverse Point Study. EPA Contract No. 68-02-3172. June 1977. 19
pp.

9. Brown, J. and K. Yu. Test Report: Particulate Sampling Strategy in Circular Ducts. Emission
Measurement Branch. U.S. Environmental Protection Agency, Research Triangle Park, NC 27711. July
31, 1980. 12 pp.

10. Hawksley, P.G.W., S. Badzioch, and J.H. Blackett. Measurement of Solids in Flue Gases.
Leatherhead, England, The British Coal Utilisation Research Association. 1961. pp. 129-133.

Method 1 05/30/2023
8

11. Knapp, K.T. The Number of Sampling Points Needed for Representative Source Sampling. In:
Proceedings of the Fourth National Conference on Energy and Environment. Theodore, L. et al. (ed).
Dayton, Dayton section of the American Institute of Chemical Engineers. October 3-7, 1976. pp. 563-568.

12. Smith, W.S. and D.J. Grove. A Proposed Extension of EPA Method 1 Criteria. Pollution Engineering.
XV (8):36-37. August 1983.

13. Gerhart, P.M. and M.J. Dorsey. Investigation of Field Test Procedures for Large Fans. University of
Akron. Akron, OH. (EPRI Contract CS-1651). Final Report (RP-1649-5). December 1980.

14. Smith, W.S. and D.J. Grove. A New Look at Isokinetic Sampling—Theory and Applications. Source
Evaluation Society Newsletter. VIII (3):19-24. August 1983.

17.0 Tables, Diagrams, Flowcharts, and Validation Data
Method 1 05/30/2023
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Method 1 05/30/2023
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TABLE 1-1 CROSS-SECTION LAYOUT FOR RECTANGULAR STACKS

Number of traverse points layout Matrix
9 3×3
12 4×3
16 4×4
20 5×4
25 5×5
30 6×5
36 6×6
42 7×6
49 7×7

TABLE 1-2—LOCATION OF TRAVERSE POINTS IN CIRCULAR STACKS

[Percent of stack diameter from inside wall to traverse point]

Traverse
point
number on
a diameter
Number of traverse points on a diameter

2

4

6

8

10

12

14

16

18

20

22

24
1 14.6 6.7 4.4 3.2 2.6 2.1 1.8 1.6 1.4 1.3 1.1 1.1
2 85.4 25.0 14.6 10.5 8.2 6.7 5.7 4.9 4.4 3.9 3.5 3.2
3 75.0 29.6 19.4 14.6 11.8 9.9 8.5 7.5 6.7 6.0 5.5
4 93.3 70.4 32.3 22.6 17.7 14.6 12.5 10.9 9.7 8.7 7.9
5 85.4 67.7 34.2 25.0 20.1 16.9 14.6 12.9 11.6 10.5
6 95.6 80.6 65.8 35.6 26.9 22.0 18.8 16.5 14.6 13.2
7 89.5 77.4 64.4 36.6 28.3 23.6 20.4 18.0 16.1
8 96.8 85.4 75.0 63.4 37.5 29.6 25.0 21.8 19.4
9 91.8 82.3 73.1 62.5 38.2 30.6 26.2 23.0
10 97.4 88.2 79.9 71.7 61.8 38.8 31.5 27.2
11 93.3 85.4 78.0 70.4 61.2 39.3 32.3
12 97.9 90.1 83.1 76.4 69.4 60.7 39.8
Method 1 05/30/2023
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13 94.3 87.5 81.2 75.0 68.5 60.2
14 98.2 91.5 85.4 79.6 73.8 67.7
15 95.1 89.1 83.5 78.2 72.8
16 98.4 92.5 87.1 82.0 77.0
17 95.6 90.3 85.4 80.6
18 98.6 93.3 88.4 83.9
19 96.1 91.3 86.8
20 98.7 94.0 89.5
21 96.5 92.1
22 98.9 94.5
23 96.8
24 98.9
Method 1 05/30/2023
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Intermountain Regional Landfill F-5 Performance Test Site Specific Test Plan
APPENDIX D

Method 7E 5/21/2018

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While we have taken steps to ensure the accuracy of this Internet version of the document, it is not the
official version. The most recent edits to this method were published here:
https://www.gpo.gov/fdsys/pkg/FR-2016-08-30/pdf/2016-19642.pdf. To see a complete version
including any recent edits, visit: https://www.ecfr.gov/cgi-bin/ECFR?page=browse and search under
Title 40, Protection of Environment.
METHOD 7E—DETERMINATION OF NITROGEN OXIDES EMISSIONS FROM STATIONARY
SOURCES (INSTRUMENTAL ANALYZER PROCEDURE)
1.0 Scope and Application
What is Method 7E?
Method 7E is a procedure for measuring nitrogen oxides (NOx) in stationary source emissions
using a continuous instrumental analyzer. Quality assurance and quality control requirements are
included to assure that you, the tester, collect data of known quality. You must document your
adherence to these specific requirements for equipment, supplies, sample collection and analysis,
calculations, and data analysis. This method does not completely describe all equipment,
supplies, and sampling and anal ytical procedures you will need but refers to other methods for
some of the details. Therefore, to obtain reliable results, you should also have a thorough
knowledge of these additional test methods which are found in appendix A to this part:
(a) Method 1—Sample and Velocity Traverses for Stationary Sources.
(b) Method 4—Determination of Moisture Content in Stack Gases.
1.1 Analytes. What does this method determine? This method measures the concentration of
nitrogen oxides as NO2.
Analyte CAS No. Sensitivity
Nitric oxide (NO) 10102-43-9 Typically <2% of
Nitrogen dioxide (NO2) 10102-44-0 Calibration Span.
1.2 Applicability. When is this method required? The use of Method 7E may be required by
specific New Source Performance Standards, Clean Air Marketing rules, State Implementation
Plans, and permits where measurement of NOx concentrations in stationary source emissions is
required, either to determine compliance with an applicable emissions standard or to conduct
performance testing of a continuous monitoring system (CEMS). Other regulations may also
require the use of Method 7E.
1.3 Data Quality Objectives (DQO). How good must my collected data be? Method 7E is
designed to provide high-quality data for determining compliance with Federal and State
emission standards and for relative accuracy testing of CEMS. In these and other applications,
the principal objective is to ensure the accuracy of the data at the actual emission levels
Method 7E 5/21/2018

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encountered. To meet this objective, the use of EPA traceability protocol calibration gases and
measurement system performance tests are required.
1.4 Data Quality Assessment for Low Emitters. Is performance relief granted when testing low-
emission units? Yes. For low-emitting sources, there are alternative performance specifications
for analyzer calibration error, system bias, drift, and response time. Also, the alternative dynamic
spiking procedure in section 16 may provide performance relief for certain low-emitting units.
2.0 Summary of Method
In this method, a sample of the effluent gas is continuously sampled and conveyed to the
analyzer for measuring the concentration of NOX. You may measure NO and NO2 separately or
simultaneously together but, for the purposes of this method, NOX is the sum of NO and NO2.
You must meet the performance requirements of this method to validate your data.
3.0 Definitions
3.1 Analyzer Calibration Error, for non-dilution systems, means the difference between the
manufacturer certified concentration of a calibration gas and the measured concentration of the
same gas when it is introduced into the analyzer in direct calibration mode.
3.2 Calibration Curve means the relationship between an analyzer's response to the injection of a
series of calibration gases and the actual concentrations of those gases.
3.3 Calibration Gas means the gas mixture containing NOX at a known concentration and
produced and certified in accordance with “EPA Traceability Protocol for Assay and
Certification of Gaseous Calibration Standards,” September 1997, as amended August 25, 1999,
EPA-600/R-97/121 or more recent updates. The tests for analyzer calibration error, drift, and
system bias require the use of calibration gas prepared according to this protocol. If a zero gas is
used for the low-level gas, it must meet the requirements under the definition for “zero air
material” in 40 CFR 72.2 in place of being prepared by the traceability protocol.
3.3.1 Low-Level Gas means a calibration gas with a concentration that is less than 20 percent of
the calibration span and may be a zero gas.
3.3.2 Mid-Level Gas means a calibration gas with a concentration that is 40 to 60 percent of the
calibration span.
3.3.3 High-Level Gas means a calibration gas with a concentration that is equal to the calibration
span.
3.4 Calibration Span means the upper limit of the analyzer's calibration that is set by the choice
of high-level calibration gas. No valid run average concentration may exceed the calibration
span. To the extent practicable, the measured emissions should be between 20 to 100 percent of
the selected calibration span. This may not be practicable in some cases of low-concentration
measurements or testing for compliance with an emission limit when emissions are substantially
Method 7E 5/21/2018

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less than the limit. In such cases, calibration spans that are practicable to achieving the data
quality objectives without being excessively high should be chosen.
3.5 Centroidal Area means the central area of the stack or duct that is no greater than 1 percent
of the stack or duct cross section. This area has the same geometric shape as the stack or duct.
3.6 Converter Efficiency Gas means a calibration gas with a known NO or NO2 concentration
and of Traceability Protocol quality.
3.7 Data Recorder means the equipment that permanently records the concentrations reported by
the analyzer.
3.8 Direct Calibration Mode means introducing the calibration gases directly into the analyzer
(or into the assembled measurement system at a point downstream of all sample conditioning
equipment) according to manufacturer's recommended calibration procedure. This mode of
calibration applies to non-dilution-type measurement systems.
3.9 Drift means the difference between the pre- and post-run system bias (or system calibration
error) checks at a specific calibration gas concentration level (i.e. low-, mid- or high-).
3.10 Gas Analyzer means the equipment that senses the gas being measured and generates an
output proportional to its concentration.
3.11 Interference Check means the test to detect analyzer responses to compounds other than the
compound of interest, usually a gas present in the measured gas stream, that is not adequately
accounted for in the calibration procedure and may cause measurement bias.
3.12 Low-Concentration Analyzer means any analyzer that operates with a calibration span of 20
ppm NOX or lower. Each analyzer model used routinely to measure low NOX concentrations
must pass a manufacturer's stability test (MST). An MST subjects the analyzer to a range of line
voltages and temperatures that reflect potential field conditions to demonstrate its stability
following procedures similar to those provided in 40 CFR 53.23. Ambient-level analyzers are
exempt from the MST requirements of section 16.3. A copy of this information must be included
in each test report. Table 7E-5 lists the criteria to be met.
3.13 Measurement System means all of the equipment used to determine the NOX concentration.
The measurement system comprises six major subsystems: Sample acquisition, sample transport,
sample conditioning, calibration gas manifold, gas analyzer, and data recorder.
3.14 Response Time means the time it takes the measurement system to respond to a change in
gas concentration occurring at the sampling point when the system is operating normally at its
target sample flow rate or dilution ratio.
3.15 Run means a series of gas samples taken successively from the stack or duct. A test
normally consists of a specific number of runs.
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3.16 System Bias means the difference between a calibration gas measured in direct calibration
mode and in system calibration mode. System bias is determined before and after each run at the
low- and mid- or high-concentration levels. For dilution-type systems, pre- and post-run system
calibration error is measured rather than system bias.
3.17 System Calibration Error applies to dilution-type systems and means the difference
between the measured concentration of low-, mid-, or high-level calibration gas and the certified
concentration for each gas when introduced in system calibration mode. For dilution-type
systems, a 3-point system calibration error test is conducted in lieu of the analyzer calibration
error test, and 2-point system calibration error tests are conducted in lieu of system bias tests.
3.18 System Calibration Mode means introducing the calibration gases into the measurement
system at the probe, upstream of the filter and all sample conditioning components.
3.19 Test refers to the series of runs required by the applicable regulation.
4.0 Interferences
Note that interferences may vary among instruments and that instrument-specific interferences
must be evaluated through the interference test.
5.0 Safety
What safety measures should I consider when using this method? This method may require you
to work with hazardous materials and in hazardous conditions. We encourage you to establish
safety procedures before using the method. Among other precautions, you should become
familiar with the safety recommendations in the gas analyzer user's manual. Occupational Safety
and Health Administration (OSHA) regulations concerning cylinder and noxious gases may
apply. Nitric oxide and NO2 are toxic and dangerous gases. Nitric oxide is immediately
converted to NO2 upon reaction with air. Nitrogen dioxide is a highly poisonous and insidious
gas. Inflammation of the lungs from exposure may cause only slight pain or pass unnoticed, but
the resulting edema several days later may cause death. A concentration of 100 ppm is dangerous
for even a short exposure, and 200 ppm may be fatal. Calibration gases must be handled with
utmost care and with adequate ventilation. Emission-level exposure to these gases should be
avoided.
6.0 Equipment and Supplies
The performance criteria in this method will be met or exceeded if you are properly using
equipment designed for this application.
6.1 What do I need for the measurement system? You may use any equipment and supplies
meeting the following specifications:
Method 7E 5/21/2018

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(1) Sampling system components that are not evaluated in the system bias or system calibration
error test must be glass, Teflon, or stainless steel. Other materials are potentially acceptable,
subject to approval by the Administrator.
(2) The interference, calibration error, and system bias criteria must be met.
(3) Sample flow rate must be maintained within 10 percent of the flow rate at which the system
response time was measured.
(4) All system components (excluding sample conditioning components, if used) must maintain
the sample temperature above the moisture dew point. Ensure minimal contact between any
condensate and the sample gas. Section 6.2 provides example equipment specifications for a
NOx measurement system. Figure 7E-1 is a diagram of an example dry-basis measurement
system that is likely to meet the method requirements and is provided as guidance. For wet-basis
systems, you may use alternative equipment and supplies as needed (some of which are
described in Section 6.2), provided that the measurement system meets the applicable
performance specifications of this method.
Section 6.2 provides example equipment specifications for a NOx measurement system. Figure
7E-1 is a diagram of an example dry basis measurement system that is likely to meet the method
requirements and is provided as guidance. For wet-basis systems, you may use alternative
equipment and supplies as needed (some of which are described in section 6.2), provided that the
measurement system meets the applicable performance specifications of this method.
6.2 Measurement System Components
6.2.1 Sample Probe. Glass, stainless steel, or other approved material, of sufficient length to
traverse the sample points.
6.2.2 Particulate Filter. An in-stack or out-of-stack filter. The filter must be made of material
that is non-reactive to the gas being sampled. The filter media for out-of-stack filters must be
included in the system bias test. The particulate filter requirement may be waived in applications
where no significant particulate matter is expected (e.g., for emission testing of a combustion
turbine firing natural gas).
6.2.3 Sample Line. The sample line from the probe to the conditioning system/sample pump
should be made of Teflon or other material that does not absorb or otherwise alter the sample
gas. For a dry-basis measurement system (as shown in Figure 7E-1), the temperature of the
sample line must be maintained at a sufficiently high level to prevent condensation before the
sample conditioning components. For wet-basis measurement systems, the temperature of the
sample line must be maintained at a sufficiently high level to prevent condensation before the
analyzer.
6.2.4 Conditioning Equipment. For dry basis measurements, a condenser, dryer or other suitable
device is required to remove moisture continuously from the sample gas. Any equipment needed
Method 7E 5/21/2018

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to heat the probe or sample line to avoid condensation prior to the sample conditioning
component is also required.
For wet basis systems, you must keep the sample above its dew point either by: (1) Heating the
sample line and all sample transport components up to the inlet of the analyzer (and, for hot-wet
extractive systems, also heating the analyzer) or (2) by diluting the sample prior to analysis using
a dilution probe system. The components required to do either of the above are considered to be
conditioning equipment.
6.2.5 Sampling Pump. For systems similar to the one shown in Figure 7E-1, a leak-free pump is
needed to pull the sample gas through the system at a flow rate sufficient to minimize the
response time of the measurement system. The pump may be constructed of any material that is
non-reactive to the gas being sampled. For dilution-type measurement systems, an ejector pump
(eductor) is used to create a vacuum that draws the sample through a critical orifice at a constant
rate.
6.2.6 Calibration Gas Manifold. Prepare a system to allow the introduction of calibration gases
either directly to the gas analyzer in direct calibration mode or into the measurement system, at
the probe, in system calibration mode, or both, depending upon the type of system used. In
system calibration mode, the system should be able to flood the sampling probe and vent excess
gas. Alternatively, calibration gases may be introduced at the calibration valve following the
probe. Maintain a constant pressure in the gas manifold. For in-stack dilution-type systems, a gas
dilution subsystem is required to transport large volumes of purified air to the sample probe and
a probe controller is needed to maintain the proper dilution ratio.
6.2.7 Sample Gas Manifold. For the type of system shown in Figure 7E-1, the sample gas
manifold diverts a portion of the sample to the analyzer, delivering the remainder to the by-pass
discharge vent. The manifold should also be able to introduce calibration gases directly to the
analyzer (except for dilution-type systems). The manifold must be made of material that is non-
reactive to the gas sampled or the calibration gas and be configured to safely discharge the
bypass gas.
6.2.8 NOX Analyzer. An instrument that continuously measures NOx in the gas stream and meets
the applicable specifications in section 13.0. An analyzer that operates on the principle of
chemiluminescence with an NO2 to NO converter is one example of an analyzer that has been
used successfully in the past. Analyzers operating on other principles may also be used provided
the performance criteria in section 13.0 are met.
6.2.8.1 Dual Range Analyzers. For certain applications, a wide range of gas concentrations may
be encountered, necessitating the use of two measurement ranges. Dual-range analyzers are
readily available for these applications. These analyzers are often equipped with automated
range-switching capability, so that when readings exceed the full-scale of the low measurement
range, they are recorded on the high range. As an alternative to using a dual-range analyzer, you
may use two segments of a single, large measurement scale to serve as the low and high ranges.
In all cases, when two ranges are used, you must quality-assure both ranges using the proper sets
of calibration gases. You must also meet the interference, calibration error, system bias, and drift
Method 7E 5/21/2018

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checks. However, we caution that when you use two segments of a large measurement scale for
dual range purposes, it may be difficult to meet the performance specifications on the low range
due to signal-to-noise ratio considerations.
6.2.8.2 Low Concentration Analyzer. When an analyzer is routinely calibrated with a calibration
span of 20 ppmv or less, the manufacturer's stability test (MST) is required. See Table 7E-5 for
test parameters.
6.2.9 Data Recording. A strip chart recorder, computerized data acquisition system, digital
recorder, or data logger for recording measurement data may be used.
7.0 Reagents and Standards
7.1 Calibration Gas. What calibration gases do I need? Your calibration gas must be NO in
N2 and certified (or recertified) within an uncertainty of 2.0 percent in accordance with “EPA
Traceability Protocol for Assay and Certification of Gaseous Calibration Standards” September
1997, as amended August 25, 1999, EPA-600/R-97/121. Blended gases meeting the Traceability
Protocol are allowed if the additional gas components are shown not to interfere with the
analysis. If a zero gas is used for the low-level gas, it must meet the requirements under the
definition for “zero air material” in 40 CFR 72.2. The calibration gas must not be used after its
expiration date. Except for applications under part 75 of this chapter, it is acceptable to prepare
calibration gas mixtures from EPA Traceability Protocol gases in accordance with Method 205
in appendix M to part 51 of this chapter. For part 75 applications, the use of Method 205 is
subject to the approval of the Administrator. The goal and recommendation for selecting
calibration gases is to bracket the sample concentrations. The following calibration gas
concentrations are required:
7.1.1 High-Level Gas. This concentration is chosen to set the calibration span as defined in
Section 3.4.
7.1.2 Mid-Level Gas. 40 to 60 percent of the calibration span.
7.1.3 Low-Level Gas. Less than 20 percent of the calibration span.
7.1.4 Converter Efficiency Gas. What reagents do I need for the converter efficiency test? The
converter efficiency gas is a manufacturer-certified gas with a concentration sufficient to show
NO2 conversion at the concentrations encountered in the source. A test gas concentration in the
40 to 60 ppm range is suggested, but other concentrations may be more appropriate to specific
sources. For the test described in section 8.2.4.1, NO2 is required. For the alternative converter
efficiency tests in section 16.2, NO is required.
7.2 Interference Check. What reagents do I need for the interference check? Use the appropriate
test gases listed in Table 7E-3 or others not listed that can potentially interfere (as indicated by
the test facility type, instrument manufacturer, etc.) to conduct the interference check. These
gases should be manufacturer certified but do not have to be prepared by the EPA traceability
protocol.
Method 7E 5/21/2018

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8.0 Sample Collection, Preservation, Storage, and Transport
Emission Test Procedure
Since you are allowed to choose different options to comply with some of the performance
criteria, it is your responsibility to identify the specific options you have chosen, to document
that the performance criteria for that option have been met, and to identify any deviations from
the method.
8.1 What sampling site and sampling points do I select?
8.1.1 Unless otherwise specified in an applicable regulation or by the Administrator, when this
method is used to determine compliance with an emission standard, conduct a stratification test
as described in section 8.1.2 to determine the sampling traverse points to be used. For
performance testing of continuous emission monitoring systems, follow the sampling site
selection and traverse point layout procedures described in the appropriate performance
specification or applicable regulation (e.g., Performance Specification 2 in appendix B to this
part).
8.1.2 Determination of Stratification. Perform a stratification test at each test site to determine
the appropriate number of sample traverse points. If testing for multiple pollutants or diluents at
the same site, a stratification test using only one pollutant or diluent satisfies this requirement. A
stratification test is not required for small stacks that are less than 4 inches in diameter. To test
for stratification, use a probe of appropriate length to measure the NOx (or pollutant of interest)
concentration at 12 traverse points located according to Table 1-1 or Table 1-2 of Method 1.
Alternatively, you may measure at three points on a line passing through the centroidal area.
Space the three points at 16.7, 50.0, and 83.3 percent of the measurement line. Sample for a
minimum of twice the system response time (see section 8.2.6) at each traverse point. Calculate
the individual point and mean NOx concentrations. If the concentration at each traverse point
differs from the mean concentration for all traverse points by no more than: (a) ±5.0 percent of
the mean concentration; or (b) ±0.5 ppm (whichever is less restrictive), the gas stream is
considered unstratified, and you may collect samples from a single point that most closely
matches the mean. If the 5.0 percent or 0.5 ppm criterion is not met, but the concentration at each
traverse point differs from the mean concentration for all traverse points by not more than: (a)
±10.0 percent of the mean concentration; or (b) ±1.0 ppm (whichever is less restrictive), the gas
stream is considered to be minimally stratified and you may take samples from three points.
Space the three points at 16.7, 50.0, and 83.3 percent of the measurement line. Alternatively, if a
12-point stratification test was performed and the emissions were shown to be minimally
stratified (all points within ± 10.0 percent of their mean or within ± 1.0 ppm), and if the stack
diameter (or equivalent diameter, for a rectangular stack or duct) is greater than 2.4 meters (7.8
ft), then you may use 3-point sampling and locate the three points along the measurement line
exhibiting the highest average concentration during the stratification test at 0.4, 1.2 and 2.0
meters from the stack or duct wall. If the gas stream is found to be stratified because the 10.0
percent or 1.0 ppm criterion for a 3-point test is not met, locate 12 traverse points for the test in
accordance with Table 1–1 or Table 1–2 of Method 1.
Method 7E 5/21/2018

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8.2 Initial Measurement System Performance Tests. What initial performance criteria must my
system meet before I begin collecting samples? Before measuring emissions, perform the
following procedures:
(a) Calibration gas verification,
(b) Measurement system preparation,
(c) Calibration error test,
(d) NO2 to NO conversion efficiency test, if applicable,
(e) System bias check,
(f) System response time test, and
(g) Interference check
8.2.1 Calibration Gas Verification. How must I verify the concentrations of my calibration
gases? Obtain a certificate from the gas manufacturer documenting the quality of the gas.
Confirm that the manufacturer certification is complete and current. Ensure that your calibration
gas certifications have not expired. This documentation should be available on-site for
inspection. To the extent practicable, select a high-level gas concentration that will result in the
measured emissions being between 20 and 100 percent of the calibration span.
8.2.2 Measurement System Preparation. How do I prepare my measurement system? Assemble,
prepare, and precondition the measurement system according to your standard operating
procedure. Adjust the system to achieve the correct sampling rate or dilution ratio (as
applicable).
8.2.3 Calibration Error Test. How do I confirm my analyzer calibration is correct? After you
have assembled, prepared and calibrated your sampling system and analyzer, you must conduct a
3-point analyzer calibration error test (or a 3-point system calibration error test for dilution
systems) before the first run and again after any failed system bias test (or 2-point system
calibration error test for dilution systems) or failed drift test. Introduce the low-, mid-, and high-
level calibration gases sequentially. For non-dilution-type measurement systems, introduce the
gases in direct calibration mode. For dilution-type measurement systems, introduce the gases in
system calibration mode.
(1) For non-dilution systems, you may adjust the system to maintain the correct flow rate at the
analyzer during the test, but you may not make adjustments for any other purpose. For dilution
systems, you must operate the measurement system at the appropriate dilution ratio during all
system calibration error checks, and may make only the adjustments necessary to maintain the
proper ratio.
Method 7E 5/21/2018

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(2) Record the analyzer's response to each calibration gas on a form similar to Table 7E-1. For
each calibration gas, calculate the analyzer calibration error using Equation 7E-1 in section 12.2
or the system calibration error using Equation 7E-3 in section 12.4 (as applicable). The
calibration error specification in section 13.1 must be met for the low-, mid-, and high-level
gases. If the calibration error specification is not met, take corrective action and repeat the test
until an acceptable 3-point calibration is achieved.
8.2.4 NO2 to NO Conversion Efficiency Test. Before or after each field test, you must conduct an
NO2 to NO conversion efficiency test if your system converts NO2 to NO before analyzing for
NOX. You may risk testing multiple facilities before performing this test provided you pass this
test at the conclusion of the final facility test. A failed final conversion efficiency test in this case
will invalidate all tests performed subsequent to the test in which the converter efficiency test
was passed. Follow the procedures in section 8.2.4.1, or 8.2.4.2. If desired, the converter
efficiency factor derived from this test may be used to correct the test results for converter
efficiency if the NO2 fraction in the measured test gas is known. Use Equation 7E-8 in section
12.8 for this correction.
8.2.4.1. Introduce NO2 converter efficiency gas to the analyzer in direct calibration mode and
record the NOx concentration displayed by the analyzer. Calculate the converter efficiency using
Equation 7E-7 in section 12.7. The specification for converter efficiency in section 13.5 must be
met. The user is cautioned that state-of-the-art NO2 calibration gases may have limited shelf
lives, and this could affect the ability to pass the 90-percent conversion efficiency requirement.
8.2.4.2 Alternatively, either of the procedures for determining conversion efficiency using NO in
section 16.2 may be used.
8.2.5 Initial System Bias and System Calibration Error Checks. Before sampling begins,
determine whether the high-level or mid-level calibration gas best approximates the emissions
and use it as the upscale gas. Introduce the upscale gas at the probe upstream of all sample
conditioning components in system calibration mode. Record the time it takes for the measured
concentration to increase to a value that is at least 95 percent or within 0.5 ppm (whichever is
less restrictive) of a stable response for both the low-level and upscale gases. Continue to
observe the gas concentration reading until it has reached a final, stable value. Record this value
on a form similar to Table 7E-2.
(1) Next, introduce the low-level gas in system calibration mode and record the time required for
the concentration response to decrease to a value that is within 5.0 percent or 0.5 ppm
(whichever is less restrictive) of the certified low-range gas concentration. If the low-level gas is
a zero gas, use the procedures described above and observe the change in concentration until the
response is 0.5 ppm or 5.0 percent of the upscale gas concentration (whichever is less
restrictive).
(2) Continue to observe the low-level gas reading until it has reached a final, stable value and
record the result on a form similar to Table 7E-2. Operate the measurement system at the normal
sampling rate during all system bias checks. Make only the adjustments necessary to achieve
proper calibration gas flow rates at the analyzer.
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(3) From these data, calculate the measurement system response time (see section 8.2.6) and then
calculate the initial system bias using Equation 7E-2 in section 12.3. For dilution systems,
calculate the system calibration error in lieu of system bias using equation 7E-3 in section 12.4.
See section 13.2 for acceptable performance criteria for system bias and system calibration error.
If the initial system bias (or system calibration error) specification is not met, take corrective
action. Then, you must repeat the applicable calibration error test from section 8.2.3 and the
initial system bias (or 2-point system calibration error) check until acceptable results are
achieved, after which you may begin sampling.
(NOTE: For dilution-type systems, data from the 3-point system calibration error test described in
section 8.2.3 may be used to meet the initial 2-point system calibration error test requirement of
this section, if the calibration gases were injected as described in this section, and if response
time data were recorded).
8.2.6 Measurement System Response Time. As described in section 8.2.5, you must determine the
measurement system response time during the initial system bias (or 2-point system calibration
error) check. Observe the times required to achieve 95 percent of a stable response for both the
low-level and upscale gases. The longer interval is the response time.
8.2.7 Interference Check. Conduct an interference response test of the gas analyzer prior to its
initial use in the field. If you have multiple analyzers of the same make and model, you need
only perform this alternative interference check on one analyzer. You may also meet the
interference check requirement if the instrument manufacturer performs this or a similar check
on an analyzer of the same make and model of the analyzer that you use and provides you with
documented results.
(1) You may introduce the appropriate interference test gases (that are potentially encountered
during a test; see examples in Table 7E-3) into the analyzer separately or as mixtures. Test the
analyzer with the interference gas alone at the highest concentration expected at a test source and
again with the interference gas and NOX at a representative NOx test concentration. For analyzers
measuring NOX greater than 20 ppm, use a calibration gas with a NOx concentration of 80 to 100
ppm and set this concentration equal to the calibration span. For analyzers measuring less than
20 ppm NOx, select an NO concentration for the calibration span that reflects the emission levels
at the sources to be tested, and perform the interference check at that level. Measure the total
interference response of the analyzer to these gases in ppmv. Record the responses and determine
the interference using Table 7E-4. The specification in section 13.4 must be met.
(2) A copy of this data, including the date completed and signed certification, must be available
for inspection at the test site and included with each test report. This interference test is valid for
the life of the instrument unless major analytical components (e.g., the detector) are replaced
with different model parts. If major components are replaced with different model parts, the
interference gas check must be repeated before returning the analyzer to service. If major
components are replaced, the interference gas check must be repeated before returning the
analyzer to service. The tester must ensure that any specific technology, equipment, or
procedures that are intended to remove interference effects are operating properly during testing.
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8.3 Dilution-Type Systems—Special Considerations. When a dilution-type measurement system
is used, there are three important considerations that must be taken into account to ensure the
quality of the emissions data. First, the critical orifice size and dilution ratio must be selected
properly so that the sample dew point will be below the sample line and analyzer temperatures.
Second, a high-quality, accurate probe controller must be used to maintain the dilution ratio
during the test. The probe controller should be capable of monitoring the dilution air pressure,
eductor vacuum, and sample flow rates. Third, differences between the molecular weight of
calibration gas mixtures and the stack gas molecular weight must be addressed because these can
affect the dilution ratio and introduce measurement bias.
8.4 Sample Collection.
(1) Position the probe at the first sampling point. Purge the system for at least two times the
response time before recording any data. Then, traverse all required sampling points, sampling at
each point for an equal length of time and maintaining the appropriate sample flow rate or
dilution ratio (as applicable). You must record at least one valid data point per minute during the
test run.
(2) Each time the probe is removed from the stack and replaced, you must recondition the
sampling system for at least two times the system response time prior to your next recording. If
the average of any run exceeds the calibration span value, that run is invalid.
(3) You may satisfy the multipoint traverse requirement by sampling sequentially using a single-
hole probe or a multi-hole probe designed to sample at the prescribed points with a flow within
10 percent of mean flow rate. Notwithstanding, for applications under part 75 of this chapter, the
use of multi-hole probes is subject to the approval of the Administrator.
8.5 Post-Run System Bias Check and Drift Assessment.
How do I confirm that each sample I collect is valid? After each run, repeat the system bias
check or 2-point system calibration error check (for dilution systems) to validate the run. Do not
make adjustments to the measurement system (other than to maintain the target sampling rate or
dilution ratio) between the end of the run and the completion of the post-run system bias or
system calibration error check. Note that for all post-run system bias or 2-point system
calibration error checks, you may inject the low-level gas first and the upscale gas last, or vice-
versa. You may risk sampling for multiple runs before performing the post-run bias or system
calibration error check provided you pass this test at the conclusion of the group of runs. A failed
final test in this case will invalidate all runs subsequent to the last passed test.
(1) If you do not pass the diagnose and fix the problem and pass another calibration error test
(Section 8.2.3) and system bias (or 2-point system calibration error) check (Section 8.2.5) before
repeating the run. Record the system bias (or system calibration error) results on a form similar
to Table 7E-2.
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(2) After each run, calculate the low-level and upscale drift, using Equation 7E-4 in section 12.5.
If the post-run low- and upscale bias (or 2-point system calibration error) checks are passed, but
the low-or upscale drift exceeds the specification in section 13.3, the run data are valid, but a 3-
point calibration error test and a system bias (or 2-point system calibration error) check must be
performed and passed before any more test runs are done.
(3) For dilution systems, data from a 3-point system calibration error test may be used to met the
pre-run 2-point system calibration error requirement for the first run in a test sequence. Also, the
post-run bias (or 2-point calibration error) check data may be used as the pre-run data for the
next run in the test sequence at the discretion of the tester.
8.6 Alternative Interference and System Bias Checks (Dynamic Spike Procedure). If I want to use
the dynamic spike procedure to validate my data, what procedure should I follow? Except for
applications under part 75 of this chapter, you may use the dynamic spiking procedure and
requirements provided in section 16.1 during each test as an alternative to the interference check
and the pre- and post-run system bias checks. The calibration error test is still required under this
option. Use of the dynamic spiking procedure for Part 75 applications is subject to the approval
of the Administrator.
8.7 Moisture correction. You must determine the moisture content of the flue gas and correct the
measured gas concentrations to a dry basis using Method 4 or other appropriate methods, subject
to the approval of the Administrator, when the moisture basis (wet or dry) of the measurements
made with this method is different from the moisture basis of either: (1) The applicable
emissions limit; or (2) the CEMS being evaluated for relative accuracy. Moisture correction is
also required if the applicable limit is in lb/mmBtu and the moisture basis of the Method 7E
NOx analyzer is different from the moisture basis of the Method 3A diluent gas (CO2 or O2)
analyzer.
9.0 Quality Control
What quality control measures must I take?
The following table is a summary of the mandatory, suggested, and alternative quality assurance
and quality control measures and the associated frequency and acceptance criteria. All of the QC
data, along with the sample run data, must be documented and included in the test report.
SUMMARY TABLE OF AQ/QC
Status
Process or
element
QA/QC
specification Acceptance criteria Checking frequency
S Identify Data
User

Regulatory Agency or other
primary end user of data
Before designing
test.
S Analyzer Design Analyzer resolution
or sensitivity
<2.0% of full-scale range Manufacturer design.
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M

Interference gas
check
Sum of responses ≤2.5% of
calibration span
Alternatively, sum of
responses:

≤0.5 ppmv for calibration
spans of 5 to 10 ppmv

≤0.2 ppmv for calibration
spans <5 ppmv

See Table 7E-3

M Calibration Gases Traceability protocol
(G1, G2)
Valid certificate required
Uncertainty ≤2.0% of tag
value

M

High-level gas Equal to the calibration
span
Each test.
M

Mid-level gas 40 to 60% of calibration
span
Each test.
M

Low-level gas <20% of calibration span Each test.
S Data Recorder
Design
Data resolution ≤0.5% of full-scale range Manufacturer design.
S Sample
Extraction
Probe material SS or quartz if stack >500
°F
East test.
M Sample
Extraction
Probe, filter and
sample line
temperature
For dry-basis analyzers,
keep sample above the dew
point by heating, prior to
sample conditioning
Each run.

For wet-basis analyzers,
keep sample above dew
point at all times, by
heating or dilution

S Sample
Extraction
Calibration valve
material
SS Each test.
S Sample
Extraction
Sample pump
material
Inert to sample constituents Each test.
S Sample
Extraction
Manifolding material Inert to sample constituents Each test.
S Moisture
Removal
Equipment
efficiency
<5% target compound
removal
Verified through
system bias check.
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S Particulate
Removal
Filter inertness Pass system bias check Each bias check.
M Analyzer &
Calibration Gas
Performance
Analyzer calibration
error (of 3-point
system calibration
error for dilution
systems)
Within ±2.0 percent of the
calibration span of the
analyzer for the low-, mid-,
and high-level calibration
gases
Before initial run and
after a failed system
bias test or drift test.

Alternative specification:
≤0.5 ppmv absolute
difference

M System
Performance
System bias (or pre-
and post-run 2-point
system calibration
error for dilution
(Systems)
Within ±5.0% of the
analyzer calibration span
for low-sacle and upscale
calibration gases
Before and after each
run.

Alternative specification:
≤0.5 ppmv absolute
difference

M System
Performance
System response
time
Determines minimum
sampling time per point
During initial
sampling system bias
test.
M System
Performance
Drift ≤3.0% of calibration span
for low-level and mid- or
high-level gases
After each test run.

Alternative specification:
≤0.5 ppmv absolute
difference

M System
Performance
NO2-NO conversion
efficiency
≥90% of certified test gas
concentration
Before or after each
test.
M System
Performance
Purge time ≥2 times system response
time
Before starting the
first run and when
probe is removed
from and re-inserted
into the stack.
M System
Performance
Minimum sample
time at each point
Two times the system
response time
Each sample point.
M System
Performance
Stable sample flow
rate (surrogate for
maintaining system
response time)
Within 10% of flow rate
established during system
response time check
Each run.
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M Sample Point
Selection
Stratification test All points within: Prior to first run.

±5% of mean for 1-point
sampling

±10% of mean for 3-point

Alternatively, all points
within:

±0.5 ppm of mean for 1-
point sampling

±1.0 ppm of mean for 3-
point sampling

A Multiple sample
points
simultaneously
No. of openings in
probe
Multi-hole probe with
verifiable constant flow
through all holes within
10% of mean flow rate
(requires Administrative
approval for Part 75)
Each run.
M Data Recording Frequency ≤1 minute average During run.
S Data Parameters Sample
concentration range
All 1-minute averages
within calibration span
Each run.
M Date Parameters Average
concentration for the
run
Run average ≤calibration
span
Each run.
S = Suggest.
M = Mandatory.
A = Alternative.
Agency.
10.0 Calibration and Standardization
What measurement system calibrations are required?
(1) The initial 3-point calibration error test as described in section 8.2.3 and the system bias (or
system calibration error) checks described in section 8.2.5 are required and must meet the
specifications in section 13 before you start the test. Make all necessary adjustments to calibrate
the gas analyzer and data recorder. Then, after the test commences, the system bias or system
calibration error checks described in section 8.5 are required before and after each run. Your
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analyzer must be calibrated for all species of NOx that it detects. Analyzers that measure NO and
NO2 separately without using a converter must be calibrated with both NO and NO2.
(2) You must include a copy of the manufacturer's certification of the calibration gases used in
the testing as part of the test report. This certification must include the 13 documentation
requirements in the EPA Traceability Protocol For Assay and Certification of Gaseous
Calibration Standards, September 1997, as amended August 25, 1999. When Method 205 is used
to produce diluted calibration gases, you must document that the specifications for the gas
dilution system are met for the test. You must also include the date of the most recent dilution
system calibration against flow standards and the name of the person or manufacturer who
carried out the calibration in the test report.
11.0 Analytical Procedures
Because sample collection and analysis are performed together (see section 8), additional
discussion of the analytical procedure is not necessary.
12.0 Calculations and Data Analysis
You must follow the procedures for calculations and data analysis listed in this section.
12.1 Nomenclature. The terms used in the equations are defined as follows:
ACE = Analyzer calibration error, percent of calibration span.
BWS = Moisture content of sample gas as measured by Method 4 or other approved method,
percent/100.
CAvg = Average unadjusted gas concentration indicated by data recorder for the test run, ppmv.
CD = Pollutant concentration adjusted to dry conditions, ppmv.
CDir = Measured concentration of a calibration gas (low, mid, or high) when introduced in direct
calibration mode, ppmv.
CGas = Average effluent gas concentration adjusted for bias, ppmv.
CM = Average of initial and final system calibration bias (or 2-point system calibration error)
check responses for the upscale calibration gas, ppmv.
CMA = Actual concentration of the upscale calibration gas, ppmv.
CNative = NOX concentration in the stack gas as calculated in section 12.6, ppmv.
CO = Average of the initial and final system calibration bias (or 2-point system calibration error)
check responses from the low-level (or zero) calibration gas, ppmv.
COA = Actual concentration of the low-level calibration gas, ppmv.
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CS = Measured concentration of a calibration gas (low, mid, or high) when introduced in system
calibration mode, ppmv.
CSS = Concentration of NOX measured in the spiked sample, ppmv.
CSpike = Concentration of NOX in the undiluted spike gas, ppmv.
CCalc = Calculated concentration of NOX in the spike gas diluted in the sample, ppmv.
CV = Manufacturer certified concentration of a calibration gas (low, mid, or high), ppmv.
CW = Pollutant concentration measured under moist sample conditions, wet basis, ppmv.
CS = Calibration span, ppmv.
D = Drift assessment, percent of calibration span.
DF = Dilution system dilution factor or spike gas dilution factor, dimensionless.
EffNO2 = NO2 to NO converter efficiency, percent.
NOxCorr = The NOx concentration corrected for the converter efficiency, ppmv.
NOxFinal = The final NOx concentration observed during the converter efficiency test in section
16.2.2, ppmv.
NOxPeak = The highest NOx concentration observed during the converter efficiency test in section
16.2.2, ppmv.
QSpike = Flow rate of spike gas introduced in system calibration mode, L/min.
QTotal = Total sample flow rate during the spike test, L/min.
R = Spike recovery, percent.
SB = System bias, percent of calibration span.
SBi = Pre-run system bias, percent of calibration span.
SBfinal = Post-run system bias, percent of calibration span.
SCE = System calibration error, percent of calibration span.
SCEi = Pre-run system calibration error, percent of calibration span.
SCEFinal = Post-run system calibration error, percent of calibration span.
12.2 Analyzer Calibration Error. For non-dilution systems, use Equation 7E-1 to calculate the
analyzer calibration error for the low-, mid-, and high-level calibration gases.
𝐴𝐴𝐴= 𝐴𝐷𝑖𝑟−𝐴𝑉
𝐴𝑆 𝑥 100 Eq. 7E-1
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12.3 System Bias. For non-dilution systems, use Equation 7E-2 to calculate the system bias
separately for the low-level and upscale calibration gases.
𝑅𝐴= 𝐴𝑆− 𝐴𝐷𝑖𝑟
𝐴𝑆 𝑥 100 Eq. 7E-2
12.4 System Calibration Error. Use Equation 7E-3 to calculate the system calibration error for
dilution systems. Equation 7E-3 applies to both the initial 3-point system calibration error test
and the subsequent 2-point calibration error checks between test runs. In this equation, the term
“Cs” refers to the diluted calibration gas concentration measured by the analyzer.
𝑅𝐴𝐴= (𝐴𝑆𝑥𝐴𝐴)− 𝐴𝑉
𝐴𝑆 𝑥 100 Eq. 7E -3
12.5 Drift Assessment. Use Equation 7E-4 to separately calculate the low-level and upscale drift
over each test run. For dilution systems, replace “SBfinal” and “SBi” with “SCEfinal” and “SCEi”,
respectively, to calculate and evaluate drift.
𝐴= |𝑅𝐴𝐴𝑖𝑛𝑎𝑙− 𝑅𝐴𝑖| Eq. 7E-4
12.6 Effluent Gas Concentration. For each test run, calculate Cavg, the arithmetic average of all
valid NOx concentration values (e.g., 1-minute averages). Then adjust the value of Cavg for bias
using Equation 7E-5a if you use a non-zero gas as your low-level calibration gas, or Equation
7E-5b if you use a zero gas as your low-level calibration gas.
𝐴𝐴𝑎𝑟= (𝐴𝐴𝑣𝑓−𝐴𝑀)𝐴𝑀𝐴−𝐴𝑀𝐴
𝐴𝑀−𝐴𝑀
+ 𝐴𝑀𝐴 Eq. 7E-5a

𝐴𝐴𝑎𝑟= (𝐴𝐴𝑣𝑓−𝐴𝑀)𝐴𝑀𝐴
𝐴𝑀−𝐴𝑀
Eq. 7E-5b

12.7 NO2—NO Conversion Efficiency. If the NOX converter efficiency test described in
section 8.2.4.1 is performed, calculate the efficiency using Equation 7E-7.
𝐴𝑒𝑒𝑀𝑀𝑥 = 𝐴𝐷𝑖𝑟
𝐴𝑉
× 100 Eq. 7E-7

12.8 NO2—NO Conversion Efficiency Correction. If desired, calculate the total
NOX concentration with a correction for converter efficiency using Equations 7E-8.
𝑁𝑁𝑥𝐴𝑛𝑟𝑟= 𝑁𝑁+ (𝑀𝑀𝑉−𝑀𝑀
𝐴𝑓𝑓𝑀𝑀2
𝑥 100) Eq. 7E-8

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12.9 Alternative NO2 Converter Efficiency. If the alternative procedure of section 16.2.2 is used,
determine the NOX concentration decrease from NOxPeak after the minimum 30-minute test
interval using Equation 7E-9. This decrease from NOxPeak must meet the requirement in section
13.5 for the converter to be acceptable.
%𝐴𝑒𝑐𝑟𝑒𝑎𝑟𝑒= 𝑀𝑀𝑥𝑀𝑒𝑎𝑘−𝑀𝑀𝑥𝐹𝑖𝑛𝑎𝑘
𝑀𝑀𝑥𝑀𝑒𝑎𝑘
𝑥 100 Eq. 7E-9
12.10 Moisture Correction. Use Equation 7E-10 if your measurements need to be corrected to a
dry basis.
𝐴𝐴=𝐴𝑉
1−𝐴𝑉𝑆
Eq. 7E-10
2.11 Calculated Spike Gas Concentration and Spike Recovery for the Example Alternative
Dynamic Spiking Procedure in section 16.1.3. Use Equation 7E-11 to determine the calculated
spike gas concentration. Use Equation 7E-12 to calculate the spike recovery.
𝐴𝐴𝑎𝑙𝑐=(𝐴𝑆𝑛𝑖𝑘𝑒)(𝑄𝑆𝑛𝑖𝑘𝑒)
𝑄𝑆𝑛𝑟𝑎𝑘
Eq. 7E-11

𝑅= 𝐴𝐴(𝐴𝑆𝑆−𝐴𝑛𝑎𝑟𝑖𝑣𝑒)+𝐴𝑛𝑎𝑟𝑖𝑣𝑒
𝐴𝑟𝑛𝑖𝑘𝑒
𝑥 100 Eq. 7E-12

13.0 Method Performance
13.1 Calibration Error. This specification is applicable to both the analyzer calibration error and
the 3-point system calibration error tests described in section 8.2.3. At each calibration gas level
(low, mid, and high) the calibration error must either be within ±2.0 percent of the calibration
span. Alternatively, the results are acceptable if |Cdir − Cv| or |Cs−Cv| (as applicable) is ≤0.5
ppmv.
13.2 System Bias. This specification is applicable to both the system bias and 2-point system
calibration error tests described in section 8.2.5 and 8.5. The pre- and post-run system bias (or
system calibration error) must be within ±5.0 percent of the calibration span for the low-level
and upscale calibration gases. Alternatively, the results are acceptable if | Cs−Cdir | is ≤0.5 ppmv
or if | Cs− Cv | is ≤0.5 ppmv (as applicable).
13.3 Drift. For each run, the low-level and upscale drift must be less than or equal to 3.0 percent
of the calibration span. The drift is also acceptable if the pre- and post-run bias (or the pre- and
post-run system calibration error) responses do not differ by more than 0.5 ppmv at each gas
concentration (i.e. | Cs post-run− Cs pre-run | ≤0.5 ppmv).
13.4 Interference Check. The total interference response (i.e., the sum of the interference
responses of all tested gaseous components) must not be greater than 2.50 percent of the
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calibration span for the analyzer tested. In summing the interferences, use the larger of the
absolute values obtained for the interferent tested with and without the pollutant present. The
results are also acceptable if the sum of the responses does not exceed 0.5 ppmv for a calibration
span of 5 to 10 ppmv, or 0.2 ppmv for a calibration span <5 ppmv.
13.5 NO2 to NO Conversion Efficiency Test (as applicable). The NO2 to NO conversion
efficiency, calculated according to Equation 7E-7, must be greater than or equal to 90 percent.
The alternative conversion efficiency check, described in section 16.2.2 and calculated according
to Equation 7E-9, must not result in a decrease from NOXPeak by more than 2.0 percent.
13.6 Alternative Dynamic Spike Procedure. Recoveries of both pre-test spikes and post-test
spikes must be within 100 ±10 percent. If the absolute difference between the calculated spike
value and measured spike value is equal to or less than 0.20 ppmv, then the requirements of the
ADSC are met.
14.0 Pollution Prevention [Reserved]
15.0 Waste Management [Reserved]
16.0 Alternative Procedures
16.1 Dynamic Spike Procedure. Except for applications under part 75 of this chapter, you may
use a dynamic spiking procedure to validate your test data for a specific test matrix in place of
the interference check and pre- and post-run system bias checks. For part 75 applications, use of
this procedure is subject to the approval of the Administrator. Best results are obtained for this
procedure when source emissions are steady and not varying. Fluctuating emissions may render
this alternative procedure difficult to pass. To use this alternative, you must meet the following
requirements.
16.1.1 Procedure Documentation. You must detail the procedure you followed in the test report,
including how the spike was measured, added, verified during the run, and calculated after the
test.
16.1.2 Spiking Procedure Requirements. The spikes must be prepared from EPA Traceability
Protocol gases. Your procedure must be designed to spike field samples at two target levels both
before and after the test. Your target spike levels should bracket the average sample
NOX concentrations. The higher target concentration must be less than the calibration span. You
must collect at least 5 data points for each target concentration. The spiking procedure must be
performed before the first run and repeated after the last run of the test program.
16.1.3 Example Spiking Procedure. Determine the NO concentration needed to generate
concentrations that are 50 and 150 percent of the anticipated NOX concentration in the stack at
the total sampling flow rate while keeping the spike flow rate at or below 10 percent of this total.
Use a mass flow meter (accurate within 2.0 percent) to generate these NO spike gas
concentrations at a constant flow rate. Use Equation 7E-11 in section 12.11 to determine the
calculated spike concentration in the collected sample.
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(1) Prepare the measurement system and conduct the analyzer calibration error test as described
in sections 8.2.2 and 8.2.3. Following the sampling procedures in section 8.1, determine the stack
NOX concentration and use this concentration as the average stack concentration (Cavg) for the
first spike level, or if desired, for both pre-test spike levels. Introduce the first level spike gas into
the system in system calibration mode and begin sample collection. Wait for at least two times
the system response time before measuring the spiked sample concentration. Then record at least
five successive 1-minute averages of the spiked sample gas. Monitor the spike gas flow rate and
maintain at the determined addition rate. Average the five 1-minute averages and determine the
spike recovery using Equation 7E-12. Repeat this procedure for the other pre-test spike level.
The recovery at each level must be within the limits in section 13.6 before proceeding with the
test.
(2) Conduct the number of runs required for the test. Then repeat the above procedure for the
post-test spike evaluation. The last run of the test may serve as the average stack concentration
for the post-test spike test calculations. The results of the post-test spikes must meet the limits in
section 13.6.
16.2 Alternative NO2 to NO Conversion Efficiency Procedures. You may use either of the
following procedures to determine converter efficiency in place of the procedure in section
8.2.4.1.
16.2.1 The procedure for determining conversion efficiency using NO in 40 CFR 86.123-78.
16.2.2 Bag Procedure. Perform the analyzer calibration error test to document the calibration
(both NO and NOX modes, as applicable). Fill a Tedlar or equivalent bag approximately half full
with either ambient air, pure oxygen, or an oxygen standard gas with at least 19.5 percent by
volume oxygen content. Fill the remainder of the bag with mid- to high-level NO in N2 (or other
appropriate concentration) calibration gas. (Note that the concentration of the NO standard
should be sufficiently high enough for the diluted concentration to be easily and accurately
measured on the scale used. The size of the bag should be large enough to accommodate the
procedure and time required. Verify through the manufacturer that the Tedlar alternative is
suitable for NO and make this verifed information available for inspection.)
(1) Immediately attach the bag to the inlet of the NOx analyzer (or external converter if used). In
the case of a dilution-system, introduce the gas at a point upstream of the dilution assembl y.
Measure the NOx concentration for a period of 30 minutes. If the NOx concentration drops more
than 2 percent absolute from the peak value observed, then the NO2 converter has failed to meet
the criteria of this test. Take corrective action. The highest NOx value observed is considered to
be NOxPeak. The final NOx value observed is considered to be NOxfinal.
(2) [Reserved]
16.3 Manufacturer's Stability Test. A manufacturer's stability test is required for all analyzers
that routinely measure emissions below 20 ppmv and is optional but recommended for other
analyzers. This test evaluates each analyzer model by subjecting it to the tests listed in Table 7E-
5 following procedures similar to those in 40 CFR 53.23 for thermal stability and insensitivity to
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supply voltage variations. If the analyzer will be used under temperature conditions that are
outside the test conditions in Table B-4 of Part 53.23, alternative test temperatures that better
reflect the analyzer field environment should be used. Alternative procedures or documentation
that establish the analyzer's stability over the appropriate line voltages and temperatures are
acceptable.
17.0 References
1. “ERA Traceability Protocol for Assay and Certification of Gaseous Calibration Standards”
September 1997 as amended, ERA-600/R-97/121.
18.0 Tables, Diagrams, Flowcharts, and Validation Data

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TABLE 7E-3—EXAMPLE INTERFERENCE CHECK GAS CONCENTRATIONS
Potential interferent gas1
Concentrations2 sample conditioning type
Hot wet Dried
CO2 5 and 15% 5 and 15%
H2O 25% 1%
NO 15 ppmv 15 ppmv
NO2 15 ppmv 15 ppmv
N2O 10 ppmv 10 ppmv
CO 50 ppmv 50 ppmv
NH3 10 ppmv 10 ppmv
CH4 50 ppmv 50 ppmv
SO2 20 ppmv 20 ppmv
H2 50 ppmv 50 ppmv
HCl 10 ppmv 10 ppmv
1Any applicable gas may be eliminated or tested at a reduced level if the manufacturer has
provided reliable means for limiting or scrubbing that gas to a specified level.
2As practicable, gas concentrations should be the highest expected at test sites.

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TABLE 7E-4—INTERFERENCE RESPONSE
Date of Test: ________________________
Analyzer Type: ______________________
Model No.: _________________________
Serial No: __________________________
Calibration Span: ____________________

Test gas type
Concentration
(ppm)
Analyzer
response

Sum of Responses

% of Calibration Span

TABLE 7E-5—MANUFACTURER STABILITY TEST
Test description
Acceptance criteria
(note 1)
Thermal Stability Temperature range when drift does not exceed 3.0% of analyzer range over
a 12-hour run when measured with NOX present @ 80% of calibration
span.
Fault Conditions Identify conditions which, when they occur, result in performance which is
not in compliance with the Manufacturer's Stability Test criteria. These are
to be indicated visually or electrically to alert the operator of the problem.
Insensitivity to
Supply Voltage
Variations
±10.0% (or manufacturers alternative) variation from nominal voltage must
produce a drift of ≤2.0% of calibration span for either zero or concentration
≥80% NOX present.
Analyzer
Calibration Error
For a low-, medium-, and high-calibration gas, the difference between the
manufacturer certified value and the analyzer response in direct calibration
mode, no more than 2.0% of calibration span.
Note 1: If the instrument is to be used as a Low Range analyzer, all tests must be performed at a
calibration span of 20 ppm or less.