EPA Method 320-Measurement of Vapor Phase Organic and Inorganic Emissions by Extractive Fourier Transform Infrared (FTIR) Spectroscopy, 15101-15115 [2024-04359]
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Federal Register / Vol. 89, No. 42 / Friday, March 1, 2024 / Proposed Rules
and low-income populations to the
greatest extent practicable and
permitted by law. EPA defines
environmental justice (EJ) as ‘‘the fair
treatment and meaningful involvement
of all people regardless of race, color,
national origin, or income with respect
to the development, implementation,
and enforcement of environmental laws,
regulations, and policies.’’ EPA further
defines the term fair treatment to mean
that ‘‘no group of people should bear a
disproportionate burden of
environmental harms and risks,
including those resulting from the
negative environmental consequences of
industrial, governmental, and
commercial operations or programs and
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TDEC did not evaluate EJ
considerations as part of its SIP
submittal; the CAA and applicable
implementing regulations neither
prohibit nor require such an evaluation.
EPA did not perform an EJ analysis and
did not consider EJ in this proposed
action. Due to the nature of the action
being proposed here, this proposed
action is expected to have a neutral to
positive impact on the air quality of the
affected area. Consideration of EJ is not
required as part of this proposed action,
and there is no information in the
record inconsistent with the stated goal
of E.O. 12898 of achieving EJ for people
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Environmental protection, Air
pollution control, Incorporation
byreference, Intergovernmental
relations, Particulate matter, Reporting
and recordkeeping requirements.
Authority: 42 U.S.C. 7401 et seq.
Dated: February 26, 2024.
Jeaneanne Gettle,
Acting Regional Administrator, Region 4.
[FR Doc. 2024–04362 Filed 2–29–24; 8:45 am]
BILLING CODE 6560–50–P
ENVIRONMENTAL PROTECTION
AGENCY
40 CFR Part 63
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[EPA–HQ–OAR–2022–0491; FRL–9992–01–
OAR]
RIN 2060–AV81
EPA Method 320—Measurement of
Vapor Phase Organic and Inorganic
Emissions by Extractive Fourier
Transform Infrared (FTIR)
Spectroscopy
Environmental Protection
Agency (EPA).
AGENCY:
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ACTION:
Proposed rule.
This action proposes editorial
and technical revisions to the
Environmental Protection Agency’s
(EPA’s) Method 320 (Measurement of
Vapor Phase Organic and Inorganic
Emissions by Extractive Fourier
Transform Infrared (FTIR)
Spectroscopy). The proposed revisions
include updating the validation and
quality assurance (QA) spiking
procedures of the method to provide a
more performance-based approach with
specified acceptance criteria. The
proposed revisions will provide
flexibility to the stack testing
community while ensuring consistent
implementation and quality of the
measurement results across emissions
sources and facilities.
DATES: Comments. Comments must be
received on or before April 30, 2024.
Public Hearing. The EPA will hold a
virtual public hearing on March 29,
2024 if a request for a virtual public
hearing is received on or before March
8, 2024. Refer to the SUPPLEMENTARY
INFORMATION section for additional
information on the virtual public
hearing.
SUMMARY:
You may submit comments,
identified by Docket ID No. EPA–HQ–
OAR–2022–0491, by any of the
following methods:
• Federal eRulemaking Portal:
https://www.regulations.gov/ (our
preferred method). Follow the online
instructions for submitting comments.
• Email: a-and-r-docket@epa.gov.
Include Docket ID No. EPA–HQ–OAR–
2022–0491 in the subject line of the
message.
• Fax: (202) 566–9744. Attention
Docket ID No. EPA–HQ–OAR–2022–
0491.
• Mail: U.S. Environmental
Protection Agency, EPA Docket Center,
Docket ID No. EPA–HQ–OAR–2022–
0491, Mail Code 28221T, 1200
Pennsylvania Avenue NW, Washington,
DC 20460.
• Hand/Courier Delivery: EPA Docket
Center, WJC West Building, Room 3334,
1301 Constitution Avenue NW,
Washington, DC 20004. The Docket
Center’s hours of operation are 8:30
a.m.—4:30 p.m., Monday—Friday
(except Federal Holidays).
Instructions: All submissions received
must include the Docket ID No. for this
rulemaking. Comments received may be
posted without change to https://
www.regulations.gov/, including any
personal information provided. For
detailed instructions on sending
comments and additional information
on the rulemaking process, see the
ADDRESSES:
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‘‘Public Participation’’ heading of the
section of
this document.
FOR FURTHER INFORMATION CONTACT: Dr.
David Nash, Office of Air Quality
Planning and Standards, Air Quality
Assessment Division (E143–02),
Environmental Protection Agency,
Research Triangle Park, NC 27711;
telephone number: (919) 541–9425; fax
number: (919) 541–0516; email address:
nash.dave@epa.gov.
SUPPLEMENTARY INFORMATION:
Preamble acronyms and
abbreviations. Throughout this
document, the use of ‘‘we,’’ ‘‘us,’’ or
‘‘our’’ is intended to refer to the EPA.
We use multiple acronyms and terms in
this preamble. While this list may not be
exhaustive, to ease the reading of this
preamble and for reference purposes,
the EPA defines the following terms and
acronyms here:
SUPPLEMENTARY INFORMATION
ASTM American Society for Testing and
Materials
CAA Clean Air Act
CBI Confidential Business Information
CFR Code of Federal Regulations
CTS calibration transfer standard
EPA Environmental Protection Agency
FTIR Fourier Transform Infrared
FTP File Transfer Protocol
IR infrared
NAICS North American Industry
Classification System
NESHAP National Emissions Standards for
Hazardous Air Pollutants
NIST National Institute of Standards and
Technology
NSPS New Source Performance Standards
NTTAA National Technology Transfer and
Advancement Act
OAQPS Office of Air Quality Planning and
Standards OMB Office of Management and
Budget
PRA Paperwork Reduction Act
PTFE polytetrafluoroethane
QA quality assurance
RFA Regulatory Flexibility Act
SF6 sulfur hexafluoride
TTN Technology Transfer Network
UMRA Unfunded Mandates Reform Act
VCS Voluntary Consensus Standard
WJC William Jefferson Clinton
mm micron
Organization of this document. The
information in this preamble is
organized as follows:
I. General Information
A. Does this action apply to me?
B. Where can I get a copy of this document
and other related information?
II. Public Participation
A. Written Comments
B. Participation in Virtual Public Hearing
III. Background
IV. Summary of Proposed Revisions to
Method 320
A. Section 1.0 (Introduction)
B. Section 2.0 (Summary of Method)
C. Section 3.0 (Definitions)
D. Section 4.0 (Interferences)
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E. Section 5.0 (Safety)
F. Section 6.0 (Equipment and Supplies)
G. Section 7.0 (Reagents and Standards)
H. Section 8.0 (Sampling and Analysis
Procedure)
I. Section 9.0 (Quality Control)
J. Section 10.0 (Calibration and
Standardization)
K. Section 11.0 (Data Analysis and
Calculations)
L. Section 12.0 (Method Performance Data
Analysis and Calculations)
M. Section 13.0 (Method Validation
Procedure)
N. Section 14.0 (Pollution Prevention)
O. Section 15.0 (Waste Management)
P. Section 16.0 (References)
Q. New Section 17.0 (Tables, Diagrams,
Flowcharts, and Validation Data)
R. Addendum To Test Method 320
IV. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory
Planning and Review and Executive
Order 14094: Modernizing Regulatory
Review
B. Paperwork Reduction Act (PRA)
C. Regulatory Flexibility Act (RFA)
D. Unfunded Mandates Reform Act
(UMRA)
E. Executive Order 13132: Federalism
F. Executive Order 13175: Consultation
and Coordination With Indian Tribal
Governments
G. Executive Order 13045: Protection of
Children From Environmental Health
Risks and Safety Risks
H. Executive Order 13211: Actions That
Significantly Affect Energy Supply,
Distribution, or Use
I. National Technology Transfer and
Advancement Act (NTTAA)
J. Executive Order 12898: Federal Actions
To Address Environmental Justice in
Minority Populations and Low-Income
Populations and Executive Order 14096:
Revitalizing Our Nation’s Commitment
to Environmental Justice for All
I. General Information
A. Does this action apply to me?
The proposed amendments to Method
320 apply to industries that are subject
to certain provisions of 40 CFR parts 60
and 63. The source categories and
entities potentially affected are listed in
table 1 of this preamble. This table is
not intended to be exhaustive, but rather
provides a guide for readers regarding
entities likely to be regulated by this
action. This table lists the types of
entities that EPA is now aware could
potentially be affected by this action.
Other types of entities not listed in the
table could also be regulated.
TABLE 1—POTENTIALLY AFFECTED SOURCE CATEGORIES
Category
NAICS a
Industry ............................................
321211 ...........................................
324110 ...........................................
325211 ...........................................
327410 ...........................................
333242 ...........................................
562211 ...........................................
327993 ...........................................
322120 ...........................................
2211, 48621, 92811, 211111,
211112, and 622110.
a North
Plywood and Composite Wood Products.
Petroleum Refineries.
Polyvinyl Chloride and Copolymers Production.
Lime Manufacturing Plants.
Semiconductor Manufacturing.
Hazardous Waste Combustors.
Mineral Wool Production.
Kraft Pulp and Paper Mills.
Stationary Reciprocating Internal Combustion Engines.
American Industry Classification System (2022).
If you have any questions regarding
the applicability of the proposed
changes to Method 320, contact the
person listed in the preceding FOR
FURTHER INFORMATION CONTACT section.
B. Where can I get a copy of this
document and other related
information?
The docket number for this action is
Docket ID No. EPA–HQ–OAR–2022–
0491. In addition to being available in
the docket, an electronic copy of the
proposed method revisions is available
on the Technology Transfer Network
(TTN) website at https://www3.epa.gov/
ttn/emc/methods/. The TTN provides
information and technology exchange in
various areas of air pollution control.
II. Public Participation
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Examples of regulated entities
A. Written Comments
Submit your comments, identified by
Docket ID No. EPA–HQ–OAR–2022–
0491, at https://www.regulations.gov
(our preferred method), or the other
methods identified in the ADDRESSES
section. Once submitted, comments
cannot be edited or removed from the
docket. The EPA may publish any
comment received to its public docket.
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Do not submit to EPA’s docket at
https://www.regulations.gov any
information you consider to be
Confidential Business Information (CBI),
Proprietary Business Information (PBI),
or other information whose disclosure is
restricted by statute. Multimedia
submissions (audio, video, etc.) must be
accompanied by a written comment.
The written comment is considered the
official comment and should include
discussion of all points you wish to
make. The EPA will generally not
consider comments or comment
contents located outside of the primary
submission (i.e., on the web, cloud, or
other file sharing system). Please visit
https://www.epa.gov/dockets/
commenting-epa-dockets for additional
submission methods; the full EPA
public comment policy; information
about CBI, PBI, or multimedia
submissions; and general guidance on
making effective comments.
B. Participation in Virtual Public
Hearing
If a request for a virtual public hearing
is received on or before March 8, 2024
the EPA will hold a virtual public
hearing on March 29, 2024. To request
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a virtual public hearing or to register to
speak at the virtual hearing, please
contact Mr. David Nash at (919) 541–
9425 or nash.dave@epa.gov. The last
day to pre-register to speak at the
hearing will be March 22, 2024. On
March 26, 2024, the EPA will post a
general agenda for the hearing that will
list pre-registered speakers in
approximate order at: https://
www3.epa.gov/ttn/emc/methods.
The EPA encourages commenters to
provide the EPA with a copy of their
oral testimony electronically by
emailing it to Mr. David Nash at nash.
dave@epa.gov. The EPA also
recommends submitting the text of your
oral comments as written comments to
the rulemaking docket.
The EPA may ask clarifying questions
during the oral presentations but will
not respond to the presentations at that
time. Written statements and supporting
information submitted during the
comment period will be considered
with the same weight as oral comments
and supporting information presented at
the public hearing.
Please note that any updates made to
any aspect of the hearing are posted
online at https://www3.epa.gov/ttn/
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emc/methods. The EPA does not intend
to publish a document in the Federal
Register announcing updates.
III. Background
Method 320 describes the procedures
for the measurement of vapor phase
organic and inorganic emissions by
Fourier Transform Infrared (FTIR)
spectroscopy. The EPA promulgated
Method 320 along with the National
Emissions Standards for Hazardous Air
Pollutants (NESHAP) for Portland
Cement Manufacturing Industry (40 CFR
part 63, subpart LLL) on June 14, 1999
(64 FR 31898) under section 112 of the
Clean Air Act (CAA) as amended. Since
promulgation, the EPA has incorporated
the use of Method 320 for demonstrating
compliance with emissions standards
into numerous NESHAP and New
Source Performance Standards (NSPS).
Over the 24-year period since
promulgation, the use of FTIR
spectroscopy has evolved as testing
contractors, analytical laboratories, the
EPA, and State entities have developed
new standard operating procedures and
methods to reflect improvements in
sampling and analytical techniques. In
2017, the EPA held a series of informal
discussions with stakeholders in the
measurement community to identify
technical issues related to measuring
emissions using FTIR spectroscopy and
potential revisions to Method 320. The
stakeholders consisted of a cross-section
of interested parties including
representatives from State regulatory
entities, various EPA offices, analytical
laboratories, emission testing firms,
analytical standards vendors,
instrument vendors, and others with
experience in FTIR spectroscopy and
Method 320. The docket for this action
contains summaries of the stakeholder
discussions.
IV. Summary of Proposed Revisions to
Method 320
In this action, the EPA proposes
technical revisions that update the
validation and quality assurance (QA)
spiking procedures of Method 320 to
provide a more performance-based
approach. The proposed revisions
would more closely align Method 320
with the EPA’s approach to emissions
measurement, which emphasizes
specifying performance-based criteria in
test methods. Instead of specifying
exactly how stack testers should use or
perform a particular method procedure,
the method defines the criteria that
must be met for a specific method
element, which provides stack testers
with flexibility while maintaining the
quality and reliability of the
measurement results. The EPA is also
proposing technical revisions and
editorial changes to clarify and update
the requirements and procedures
specified in Method 320, including
removing the batch sampling
procedures.
A. Section 1.0 (Introduction)
In this action, the EPA proposes to
revise the name of section 1.0 from
‘‘Introduction’’ to ‘‘Scope and
Application,’’ to update the
introductory paragraph to remove
references to the FTIR Protocol, and to
remove the note regarding use of sample
conditioning systems. The EPA also
proposes to renumber and update
sections 1.1.1 (Analytes) and 1.1.2
(Applicability) to sections 1.1 and 1.2,
respectively, and to replace the existing
sections 1.2 (Method Range and
Sensitivity), 1.3 (Sensitivity), and 1.4
(Data Quality) with a revised section 1.3
(Data Quality Objectives).
B. Section 2.0 (Summary of Method)
In this action, the EPA proposes to
update section 2.0 by revising sections
2.1 (Principle) and 2.2 (untitled) and
removing sections 2.3 (Reference
Spectra Availability) and 2.4 (Operator
Requirements). In section 2.1, the EPA
proposes to remove the title and
consolidate sections 2.1.1 through 2.1.5
and the introductory paragraph to
15103
section 2.2 (Sampling and Analysis) into
a single paragraph. In section 2.2, the
EPA also proposes to remove the
discussion of Beer’s Law in section 2.2.1
and to update the references to method
evaluation and validation and pre-test
procedures.
C. Section 3.0 (Definitions)
In this action, the EPA proposes to
remove the following definitions for
technical terms that are not needed in
the proposed Method 320 and for terms
commonly used in the emissions
measurement community for which a
definition is unnecessary:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Batch Sampling.
Concentration.
Continuous Sampling.
Emissions Test.
Gas Cell.
Independent Sample.
Interferant.
Measurement.
One Hundred Percent Line.
Quantitation Limit.
Reference Calibration Transfer
Standard (CTS).
Root Mean Square Difference.
Sample Analysis.
Sampling Resolution.
Sampling System.
Screening.
Sensitivity.
Standard Spectrum.
Surrogate.
Test CTS.
Truncation.
Zero Filling.
Validation.
Validation Run.
The EPA also proposes revisions to
five definitions currently used in
Method 320. Table 2 of this preamble
presents the proposed revisions for each
definition.
TABLE 2—PROPOSED REVISIONS TO EXISTING DEFINITIONS
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Term
Revision
Proposed definition
Analyte .................................
Clarify that Method 320 can measure more than one
analyte per test.
Background Deviation ..........
Move the performance criteria from the definition to revised section 13.2 (Background Deviation).
Update the definition to remove the redundant ‘‘standard’’ in the term and to specify the acceptable CTS
gases.
CTS [Calibration Transfer
Standard] Standard.
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Analyte means a compound that the method is intended to measure. This method is a multi-component method; therefore, several analytes may be targeted for a given test.
Background deviation means a deviation from 100%
transmittance in any region of the 100% line.
Calibration transfer standard (CTS) means a certified
gas calibration standard used to verify instrument
stability. For the purposes of this method, the CTS
must be ethylene, methane, or carbon dioxide. Other
compounds may be used only with the Administrator’s approval.
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TABLE 2—PROPOSED REVISIONS TO EXISTING DEFINITIONS—Continued
Term
Revision
Reference Spectrum ............
Change the term to plural (i.e., ‘‘Reference Spectra’’),
clarify the definition, and remove the reference to the
FTIR Protocol.
Run .......................................
Replace ‘‘measurements’’ with ‘‘samples’’ and remove
the minimum requirement specifications.
The EPA also proposes to add
definitions for the key technical terms
shown in table 3 of this preamble to
Proposed definition
Reference spectra means a spectra of a pure sample
gas obtained at a known concentration under controlled conditions of pressure, temperature, and
pathlength.
Run means a series of samples taken successively
from the stack or duct. A test normally consists of a
specific number of runs.
improve the clarity of the principles and
procedures used in Method 320.
TABLE 3—PROPOSED NEW DEFINITIONS
Term
Proposed definition
Absorbance ..........................
The negative logarithm of transmission represented by the relationship A = ¥log(I/I0), where I is the transmitted
intensity of light, and I0 is the incident intensity of light upon a molecule.
The amount of infrared radiation absorbed by each molecule.
The process of quantitatively adding calibration standards to source effluent. Analyte spiking is used to evaluate
the ability of the sample transport and FTIR measurement systems to quantify the target analyte(s).
The method used to quantify the concentration of both target analyte(s) and additional compounds in a sample
matrix that may introduce analytical interferences in each FTIR spectrum.
A spectral feature that complicates, and may even prevent, the analysis of an analyte. Analytical interferences
can be background or spectral interferences. Background interferences result from a change in light throughput
relative to the single beam background. This can be due to factors such as deposits on reflective surfaces and
windows, temperature changes, a change in detector sensitivity, a change in infrared source output, or instrument electronics failure. Spectral interferences arise due to the presence of interfering compounds that have
overlapping absorption features with the analytes of interest.
A mathematical transformation that is used to adjust the instrument line shape for measured peaks. There are
various types of apodization functions; the most common are boxcar, triangular, Happ-Genzel, and Beer-Norton
functions.
A spectrum taken in the absence of absorbing species or sample gas matrix, typically conducted using nitrogen
or zero air.
The width of a spectral feature. This width is commonly listed as the full width at half the maximum of the spectral feature.
A device located in the interferometer that divides the incoming infrared radiation into two separate beams that
travel two separate paths before recombination.
A method of analyzing multicomponent spectra by scaling reference absorbance spectra to unknown measured
spectra.
A transmission or absorbance spectrum derived by dividing the sample single beam spectrum by the background
spectrum.
A mathematical transform that allows the conversion of the detector response as a function of time to intensity as
a function of frequency.
An NIST-traceable CTS reference spectrum with known temperature and pressure that has been obtained using
an absorption cell with an accurately known optical pathlength.
A pattern that contains the effects of the wave interference that are produced from an interferometer.
A device used to produce interference spectra, by dividing a beam of radiant energy into two or more paths. One
path strikes a fixed mirror and the second path strikes a moving mirror generating an optical path difference
that varies over time between them. The recombined beams produce constructive and destructive interference
as a function of changing pathlength. The Michelson interferometer, used in FTIR instruments, performs this
function.
A method for analyzing multicomponent spectra by combining features from principal component and multiple regression analysis. It has been found to be most useful when predicting a set of dependent variables from a
large set of independent variables.
The minimum separation that two spectral features must have to distinguish one feature from the another.
The optical path difference between two beams in an interferometer.
The Fourier transformed interferogram representing detector response versus wavenumber.
The series of runs required by the applicable regulation.
A stable, non-reactive species that is easily transportable and can be blended in a gas cylinder with a target
analyte to confirm the dilution ratio of a dynamic spike.
The amount of infrared radiation that is not absorbed by the sample. Percent transmittance is represented by the
following equation: %T = (I/I0) × 100.
Absorptivity ...........................
Analyte Spiking ....................
Analytical Algorithm ..............
Analytical Interference ..........
Apodization ...........................
Background Spectrum ..........
Bandwidth .............................
Beam Splitter ........................
Classical Least Squares ......
Double Beam Spectrum .......
Fourier Transform ................
Fundamental CTS ................
Interferogram ........................
Interferometer .......................
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Partial Least Squares ...........
Resolution ............................
Retardation ...........................
Single Beam Spectrum ........
Test ......................................
Tracer Gas ...........................
Transmittance .......................
D. Section 4.0 (Interferences)
In section 4.0 (Interferences), the EPA
proposes to consolidate sections 4.1
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(Analytical Interferences) and 4.2
(Sampling System Interferences) into
revised section 4.0 and to incorporate
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the discussion of background and
spectral interferences in sections 4.1.1
and 4.1.2, respectively, into the
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definition of ‘‘Analytical Interference.’’
The EPA also proposes to remove
sections 4.1.1, 4.1.2, and 4.2.
E. Section 5.0 (Safety)
In this action, the EPA proposes
updates to the language of section 5.0,
including a recommendation to provide
safety data sheets for gas standards to all
personnel using the method.
F. Section 6.0 (Equipment and Supplies)
In this action, the EPA proposes to
organize the equipment list in section
6.0 into analytical instrumentation and
sampling system components. The EPA
also proposes to remove the
descriptions of the following
equipment, which are not needed to
perform revised Method 320:
•
•
•
•
15105
Calibration/Analyte Spike Assembly.
Mass Flow Meter.
Rotameter.
FTIR Cell Pump.
In this action, the EPA proposes to
revise the current descriptions for the
equipment components shown in table
4 of this preamble.
TABLE 4—PROPOSED REVISIONS TO EXISTING DEFINITIONS
Equipment
Revision
Proposed description
FTIR Analytical System .......
Change ‘‘FTIR Analytical System’’ to ‘‘FTIR Spectrometer,’’ clarify the description, and remove the requirement that the system include a personal computer
and processing software.
Clarify the description and add recommendations regarding materials of construction.
An instrument that collects and digitizes the spectral interference pattern from an interferometer and mathematically transforms this signal into infrared frequency spectra.
A regulator used to introduce individual gas or gas mixtures from cylinders. Regulator should be constructed
of the appropriate materials that minimize analyte adsorption and reactivity.
A manifold capable of delivering nitrogen or calibration
gases through the sampling system or directly to the
FTIR. The calibration gas manifold must provide accurate dilution of the calibration gas as necessary,
monitor calibration gas pressure, and introduce
analyte spikes into the sample stream (prior to the
particulate filter) at a precise and known flowrate.
A glass wool plug (optional) inserted at the probe tip
(for large particulate removal) and a filter (required)
connected at the outlet of the heated probe and rated
for 99% removal efficiency of 1 micron (μm) aerodynamic particulate.
Polytetrafluoroethane (PTFE), 316-stainless steel, or
other inert material, of suitable length and diameter
used to connect cylinder regulators to the gas manifold.
Heated to prevent sample condensation, and made of
stainless steel, PTFE, or other material that minimizes adsorption of analytes. Line length should be
the minimum necessary to reach sampling locations.
A leak-free pump with bypass valve, capable of producing a sample flow rate equal to 5 cell volumes per
sample cycle. The pump may be positioned upstream
or downstream of the FTIR cell. If the pump is positioned upstream of the distribution manifold and FTIR
system, use a heated head pump that is constructed
from materials non-reactive with the analytes of interest.
An optional part of the sampling system used to dilute
or remove particulate matter, water vapor, or other
interfering species depending upon the source matrix
composition.
Glass, stainless steel, PTFE, or other appropriate material to transport analytes to the IR gas cell. The sampling probe must be capable of sustained heating to
prevent water condensation and adsorption of
analytes.
PTFE, 316-stainless steel, or other inert material, of
suitable length and diameter used to connect cylinder
regulators to the gas manifold.
Gas Regulators ....................
Gas Sample Manifold ..........
Change ‘‘Gas Sample Manifold’’ to ‘‘Gas Distribution
Manifold’’ and clarify the description to include requirements for accurately diluting calibration gas,
monitoring calibration gas pressure, and precisely introducing analyte spikes.
Particulate Filters .................
Clarify the description and remove the example cited ...
Polytetrafluoroethane Tubing
Incorporate the description into a single description for
‘‘Tubing’’.
Sampling Line/Heating System.
Change ‘‘Sampling Line/Heating System’’ to ‘‘Sample
Line’’ and clarify that the construction material should
minimize adsorption of analytes and the length of line
needed.
Update the minimum flow rate requirements, clarify the
options for pump placement, remove the requirement
to record the gas cell sample pressure for pumps located downstream of the FTIR system, and remove
the example cited.
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Sample Pump ......................
Sample Conditioning ............
Clarify the role of the optional sample conditioning in
the sampling system.
Sampling Probe ...................
Clarify the description and remove the example for
high-temperature stack samples and the recommendation to use a dilution probe for high-moisture sources.
Stainless Steel Tubing .........
Incorporate the description into a single description for
‘‘Tubing’’.
The EPA also proposes to add
descriptions for the equipment
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components shown in table 5 of this
preamble.
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TABLE 5—PROPOSED NEW EQUIPMENT DESCRIPTIONS
Term
Computer/Data Acquisition
System.
Gas Absorption Cell .............
Sampling System .................
Proposed description
A computer with compatible FTIR software for control of the FTIR system, acquisition of infrared (IR) data, and
analysis of resulting spectra. This system must have enough data storage space to archive all necessary infrared and meta data (see section 11.6 of this method).
The container through which the infrared beam interacts with the sample gas. The gas absorption cell must have
the ability to monitor the pressure and temperature of the sample gas.
The sampling system consists of the components listed in sections 6.2.1 through 6.2.9 of this method, validated
as detailed in section 9.4.
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G. Section 7.0 (Reagents and Standards)
In this action, the EPA proposes to
rename current section 7.1 from
‘‘Analyte(s) and Tracer Gas’’ to
‘‘Analyte(s) and Tracer Standard Gases’’
and to require the use of EPA protocol
gases (with expanded uncertainty ≤2%)
be used for criteria pollutants. The EPA
proposes to specify that other pollutants
(non-criteria) be dual certified and that
target analytes be within 25% of the
emission source level or applicable
compliance limit. The EPA also
proposes to remove the suggestion
regarding the use of sulfur hexafluoride
(SF6) tracer gas. The EPA is specifically
soliciting comment on the approach of
using expanded uncertainty for criteria
pollutants as well as not being
prescriptive on the tracer that is used.
In section 7.2 (Calibration Transfer
Standard(s)), the EPA proposes to
remove the requirements to select CTS
according to section 4.5 of the FTIR
Protocol and to obtain a NIST-traceable
standard. The EPA also proposes to
clarify that the CTS must be vendorcertified to ±2percent of the cylinder tag
value and specifying the list of CTS
standard gases that may be used. The
EPA is soliciting comments regarding
CTS gases and providing
standardization there to ensure coverage
over a wide wavelength range by using
one of the listed gases.
The EPA also proposes to change the
name of section 7.3 from ‘‘Reference
Spectra’’ to ‘‘Chemical Standards,’’ and
to replace the reference to EPA reference
spectra and procedures in the FTIR
Protocol for preparing reference spectra
with requirements to use NIST-certified
or NIST-traceable, vendor-certified
chemical standards that meet an
accuracy specification of ±5 percent for
preparing reference spectra.
H. Section 8.0 (Sampling and Analysis
Procedure)
In this action, the EPA proposes to
change the name of section 8.0 from
‘‘Sampling and Analysis Procedure’’ to
‘‘Sample Collection, Preservation,
Storage, and Transport,’’ to clarify the
purpose of the section in the
introductory paragraph, and to remove
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the list of testing requirements. The EPA
proposes to remove the
recommendation to obtain an initial
spectrum for determining a suitable
operational path length and the
reference to Figure 1 (sampling train).
In section 8.1 (currently Pretest
Preparations and Evaluations), the EPA
proposes to rename the section to
‘‘Pretest Preparations’’ and to remove
reference to section 4 of the FTIR
Protocol for determining the optimum
sampling system configuration. In
section 8.2 (Leak-Check), the EPA
proposes to remove the hyphen from the
section title, add a statement for the user
to follow the leak check procedures in
the proposed revised section 11.1 (Leak
Check), and remove sections 8.2.1
(Sampling System) and 8.2.2 (Analytical
System Leak Check).
In section 8.3 (Detector Linearity), the
EPA proposes to replace the text with a
statement for the user to follow the
detector linearity verification
procedures in proposed revised section
11.2 (Detector Linearity). The EPA
proposes to remove sections 8.3.1 and
8.3.2, which provide the options to
verify detector linearity by varying the
power incident on the detector by
modifying the aperture setting or by
using neutral density filters to attenuate
the infrared beam in current,
respectively. The EPA also proposed to
incorporate section 8.3.3 into the
proposed revised section 11.2.
For section 8.4 (Data Storage
Requirements), the EPA proposes to
replace the data storage requirements
with a statement for the user to follow
the data storage requirements in new
proposed section 11.8 (Digital Data
Storage). The EPA also proposes to
remove the requirement to prepare a
backup copy of the field test spectra and
the requirement to record sample
conditions, instrument settings, and test
records.
In section 8.5 (Background Spectra),
the EPA proposes to remove the
requirement to evacuate the gas cell and
fill the cell with dry nitrogen to ambient
pressure. The EPA also proposes to
remove the requirement to create a
backup copy of the background
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interferogram and processed singlebeam spectrum and remove sections
8.5.1 (Interference Spectra) and 8.5.2 for
collection of water vapor spectra.
For section 8.6 (Pre-Test Calibrations),
the EPA proposes to revise the
requirements for the CTS in section
8.6.1 (Calibration Transfer Standard)
and to replace the QA spike
requirements in section 8.6.2 (QA
Spike) with a statement for the user to
follow the QA spike requirements in
new proposed section 11.4 (QA Spike).
The EPA proposes to revise section
8.7 (Sampling) by replacing the
introductory paragraph with a statement
for the user to follow the sampling
procedures specified in new proposed
section 11.5 (Stratification Check). The
EPA also proposes to incorporate the
requirements for the signal
transmittance from section 8.9
(Sampling QA and Reporting) into the
introductory paragraph and to remove
sections 8.7.1 (Batch Sampling) and
8.7.2 (Continuous Sampling).
For section 8.8 (Sampling QA and
Reporting), the EPA proposes to rename
the section ‘‘Post-Run CTS’’ and add a
requirement to record a post-run CTS.
The EPA proposes to incorporate the
requirement that sample integration
times be sufficient to achieve the
required signal-to-noise ratio from
section 8.8.1 into a proposed revised
section 9.1.1.1. The EPA also proposes
to remove sections 8.8.1, 8.8.2, 8.8.3,
and 8.8.4 and instead specify the
requirements to assign unique file
names, store two copies of
interferograms and spectra, and prepare
sample spectrum documentation,
respectively.
For section 8.9 (Signal
Transmittance), the EPA proposes to
incorporate the requirements for the
signal transmittance from section 8.9
into revised section 8.7, and to replace
the text in section 8.9 with a proposed
requirement to perform post-run QA
according to proposed revised section
9.1.2 (Post-Run QA).
In section 8.10 (Post-Test QA), the
EPA proposes to move the post-test CTS
requirements to new proposed section
11.6 (Post-Test CTS). The EPA also
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proposes to move section 8.11 (Post-Test
QA) to proposed revised section 9.1.2
(Post-Run QA).
I. Section 9.0 (Quality Control)
In this action, the EPA proposes to
rename section 9.0 to ‘‘Quality
Assurance and Quality Control’’ and to
remove the introductory sentence. The
EPA proposes to replace section 9.1
(Spike Materials), which specifies the
accuracy requirements for spike
materials, with revised section 9.1
(Quality Assurance) and to add
requirements for performing pre-test
QA. The EPA proposes to move the
existing section 8.11 to the proposed
revised section 9.1.2 and to remove the
reference to the FTIR Protocol.
For section 9.2 (Spiking Procedure),
the EPA proposes to replace the spiking
procedures with a proposed revised
section 9.2 (Quality Control) stating that
analyte spike procedure in new
proposed section 9.3 (Spike Procedure)
and the validation procedure in new
proposed section 9.4 (Method
Validation Procedure) evaluate the
sampling system performance and
quantify sampling system effects on the
measured concentrations. The EPA also
proposes to clarify that the method is
self-validating, provided that the results
meet the performance requirement of
the QA spike in new proposed section
11.4, and to remove the requirement
that the results from a previous method
validation support the use of this
method in the application.
J. Section 10.0 (Calibration and
Standardization)
In this action, the EPA proposes
updates to section 10.0 by replacing
section 10.1 (Signal-to-Noise Ratio) with
a revised section 10.1 (Analytes) that
specifies the procedures for calibrating
and standardizing analytes, replacing
section 10.2 (Absorbance Path Length)
with a revised section 10.2
(Interferents), and replacing section 10.3
(Instrument Resolution) with revised
section 10.3 (CTS Absorption Bands).
The EPA proposes to replace section
10.4 (Apodization Function) with a
revised section 10.4 (Reference Spectra),
which would provide users with
procedures for collecting reference
spectra, and to replace section 10.5
(FTIR Cell Volume) with a revised
15107
section 10.5 (Absorption Cell Path
Length Determination), which would
specify the revised procedures for
determining the absorption cell path
length. The EPA also proposes to add
new section 10.6 (Instrument
Resolution) to revise procedures for
determining instrument resolution.
K. Section 11.0 (Data Analysis and
Calculations)
In this action, the EPA proposes to
change the title of current section 11.0
to ‘‘Method Procedures.’’ The EPA
proposes to replace section 11.1
(Spectral De-Resolution) with a revised
section 11.1 that would provide two
options to verify that there are no
significant vacuum-side leaks (i.e., the
low-flow test and the vacuum-decay
test) and to replace section 11.2 (Data
Analysis) with a revised section 11.2
that would incorporate the requirements
in the current introductory paragraph
for section 8.3 and requirements in
section 8.3.3. The EPA also proposes to
add several new sections as summarized
in table 6 of this preamble. The EPA
requests comment on these leak check
approaches.
TABLE 6—PROPOSED ADDITIONS TO SECTION 11
Section
Description
11.3 (Gas Cell Pathlength) ..
11.4 (QA Spike) ...................
Requires verification of the gas cell pathlength according to the procedures in revised section 10.6.4.
Clarifies that the QA spike procedure assumes that the method has been validated for each of the target analyte
at the source, rather than for only some of the target analytes as specified in current section 8.6.2 and presents the revised QA spike procedures for use of a certified standard or use of a non-certified standard.
Specifies the revised sampling procedures, including performing a stratification check.
Requires comparison of the pre- and post-test CTS spectra.
Specifies the revised recording and reporting requirements.
Incorporates the requirements from section 8.4.
11.5
11.6
11.7
11.8
(Sampling) ....................
(Post-Test CTS) ...........
(Record and Report) ....
(Digital Data Storage) ..
L. Section 12.0 (Method Performance
Data Analysis and Calculations)
For section 12.0, the EPA proposes to
rename the section ‘‘Data Analysis and
Calculations’’ and to replace section
12.1 (Spectral Quality) with a revised
section 12.1 that specifies the required
capabilities of the concentration
algorithm. The EPA also proposes to
remove section 12.2 (Sampling QA/QC).
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M. Section 13.0 (Method Validation
Procedure)
In this action, the EPA proposes to
rename current section 13.0 from
‘‘Method Validation Procedure’’ to
‘‘Method Performance’’ and to remove
the introductory paragraph. The EPA
also proposes to replace section 13.1
with a revised section 13.1 (Detection
Level), which would include the
proposed requirement that the detection
level must be within 20 percent of the
applicable compliance limit, and to
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replace section 13.2 (Batch Sampling)
with a revised section 13.2 (Background
Deviation), which would incorporate
the performance criteria in the current
definition of ‘‘Background Deviation.’’
N. Section 14.0 (Pollution Prevention)
In section 14.0, the EPA proposes to
remove the sentence describing the
mass of HAP that may be emitted by the
extracted sample gas for a typical 3-hour
validation run.
O. Section 15.0 (Waste Management)
The EPA is not proposing any changes
to section 15.0 in this action.
P. Section 16.0 (References)
In section 16.0, the EPA proposes to
remove references 1, 2, 4, and 5 through
7, and to add the reference citation and
link for the FTIR Protocol (the current
addendum to Method 320).
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Q. Section 17.0 (Tables, Diagrams,
Flowcharts, and Validation Data)
In this action, the EPA proposes to
add new section 17.0, to update Figure
1 (Extractive FTIR Sampling System),
and to remove Table 1 (Example
Presentation of Sampling
Documentation) and Figure 2
(Fractional Reproducibility).
R. Addendum to Test Method 320
In this action, the EPA proposes to
remove the addendum and associated
appendices from Method 320. The
proposed revised section 16.0 will
include a reference citation and link for
the FTIR Protocol.
IV. Statutory and Executive Order
Reviews
Additional information about these
statutes and Executive orders can be
found at https://www2.epa.gov/lawsregulations/laws-and-executive-orders.
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Federal Register / Vol. 89, No. 42 / Friday, March 1, 2024 / Proposed Rules
A. Executive Order 12866: Regulatory
Planning and Review and Executive
Order 14094: Modernizing Regulatory
Review
This action is not a significant
regulatory action as defined in
Executive Order 12866, as amended by
Executive Order 14094, and was
therefore not subject to a requirement
for Executive Order 12866 review.
B. Paperwork Reduction Act (PRA)
This action does not impose an
information collection burden under the
PRA. The revisions being proposed in
this action to Method 320 do not add
information collection requirements but
make corrections, clarifications, and
updates to existing testing methodology.
C. Regulatory Flexibility Act (RFA)
I certify that this action will not have
a significant economic impact on a
substantial number of small entities
under the RFA. This proposed action
will not impose any requirements on
small entities. The proposed revisions to
Method 320 do not impose any
requirements on regulated entities.
Rather, the proposed changes improve
the quality of the results when required
by other rules to use Method 320.
Revisions proposed for Method 320
allow contemporary advances in
analysis techniques to be used.
D. Unfunded Mandates Reform Act
(UMRA)
This action does not contain any
unfunded mandate as described in
UMRA, 2 U.S.C. 1531–1538, and does
not significantly or uniquely affect small
governments. This action imposes no
enforceable duty on any State, local or
Tribal governments or the private sector.
E. Executive Order 13132: Federalism
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This action does not have federalism
implications. It will not have substantial
direct effects on the States, on the
relationship between the national
government and the States, or on the
distribution of power and
responsibilities among the various
levels of government.
F. Executive Order 13175: Consultation
and Coordination With Indian Tribal
Governments
This action does not have Tribal
implications as specified in Executive
Order 13175. The revisions being
proposed in this action make
corrections, clarifications, and updates
to existing testing methodology. Thus,
Executive Order 13175 does not apply
to this action.
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G. Executive Order 13045: Protection of
Children From Environmental Health
Risks and Safety Risks
The EPA interprets Executive Order
13045 as applying only to those
regulatory actions that concern
environmental health or safety risks that
the EPA has reason to believe may
disproportionately affect children, per
the definition of ‘‘covered regulatory
action’’ in section 2–202 of the
Executive order.
Therefore, this action is not subject to
Executive Order 13045 because it does
not concern an environmental health
risk or safety risk. Since this action does
not concern human health, EPA’s Policy
on Children’s Health also does not
apply.
H. Executive Order 13211: Actions That
Significantly Affect Energy Supply,
Distribution or Use
This action is not subject to Executive
Order 13211 because it is not a
significant regulatory action under
Executive Order 12866.
I. National Technology Transfer and
Advancement Act (NTTAA)
This action involves technical
standards. While the EPA identified
ASTM D6348 as being potentially
applicable, the Agency does not propose
to use it. Currently, ASTM International
(formerly the American Society for
Testing and Materials) is revising ASTM
D6348 (Standard Test Method for
Determination of Gaseous Compounds
by Extractive Direct Interface FTIR
Spectroscopy), which specifies
sampling and analytical procedures that
are similar to EPA Method 320. Because
the revised ASTM D6348 may be an
equivalent method, the EPA will
reconsider it when the revised ASTM
D6348 becomes available.
J. Executive Order 12898: Federal
Actions To Address Environmental
Justice in Minority Populations and
Low-Income Populations and Executive
Order 14096: Revitalizing Our Nation’s
Commitment to Environmental Justice
for All
The EPA believes that this type of
action does not concern human health
or environmental conditions and,
therefore, cannot be evaluated with
respect to potentially disproportionate
and adverse effects on communities
with environmental justice concerns.
This action would correct, update, and
clarify Method 320 to improve the
quality of the results when used.
List of Subjects in 40 CFR Part 63
Environmental protection, Air
pollution control, Hazardous air
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pollutants, Method 320, FTIR, Test
methods.
Michael S. Regan,
Administrator.
For the reasons stated in the
preamble, the Environmental Protection
Agency proposes to amend title 40,
chapter I of the Code of Federal
Regulations as follows:
PART 63—NATIONAL EMISSION
STANDARDS FOR HAZARDOUS AIR
POLLUTANTS FOR SOURCE
CATEGORIES
1. The authority citation for part 63
continues to read as follows:
■
Authority: 42 U.S.C. 7401 et seq.
2. Appendix A to part 63 is amended
by revising Test Method 320 to read as
follows:
■
Appendix A to Part 63—Test Methods
*
*
*
*
*
Test Method 320—Measurement of Vapor
Phase Organic and Inorganic Emissions by
Extractive Fourier Transform Infrared
(FTIR) Spectroscopy
1.0 Scope and Application
This method describes the extractive
sampling and quantitative analysis of gaseous
compounds in stationary source effluent
using Fourier transform infrared (FTIR)
spectrometry. Analysis procedures, quality
control, and quality assurance requirements
are included to assure that you, the tester,
collect data of known and acceptable quality
for each testing program.
1.1 Analytes. This method is designed to
measure individual gas phase hazardous air
pollutants (HAPs) for which reference spectra
have been developed. Other gas phase
compounds can also be measured with this
method so long as reference spectra obtained
according to section 10.5 of this method are
used. Candidate gaseous compounds must
have infrared features (i.e., a non-zero dipole
moment) to be detected using this method.
1.2 Applicability. This method applies to
the analysis of vapor phase compounds that
absorb energy in the mid-infrared spectral
region, from about 400 to 4000 cm¥1 (25 to
2.5 mm). The method is used to determine
compound-specific concentrations in a multicomponent gas sample extracted from a stack
or ducted source.
1.3 Data Quality Objectives (DQOs).
Method 320 contains performance-based
DQOs to provide data of known quality. With
this method, you must evaluate the accuracy
and precision of data in each gas matrix and
at actual emissions concentrations that are
encountered during its application. Data
quality requirements include appropriate
field evaluation procedures.
2.0 Summary of Method
2.1 A sample is extracted from the source
at a constant rate. Samples are conditioned,
if necessary, and transported via heated lines
composed of inert material (to prevent
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condensation of the measured compounds)
from the source to a heated cell in the FTIR,
wherein data are generated by directing an
infrared beam through the sample to a
detector. Most molecules absorb infrared
radiation, and the absorbance occurs in a
characteristic and reproducible pattern. FTIR
data are transformed into a frequency-based
spectra and curve fitting calculations (e.g.,
classical least squares, partial least squares)
are used to determine compound quantities
and minimize residuals. Target compound
concentrations are determined using their
unique infrared absorption features and
reference calibration spectra. This method
may be used simultaneously for multiple
gaseous components.
2.2 Measurement evaluation and
validation for a source gas matrix are
described in section 9.2 of this method. Pretest preparation and procedures are described
in section 8.1 of this method. These
procedures are designed to verify that an
appropriate sampling system has been
chosen and performs in a manner that
provides results of known and acceptable
quality is also discussed. Dynamic spiking is
used to confirm target compound transport
accuracy in potentially complex matrices.
3.0 Definitions
3.1 Absorbance means the negative
logarithm of transmission represented by the
relationship A = ¥log(I/I0), where I is the
transmitted intensity of light, and I0 is the
incident intensity of light upon a molecule.
3.2 Absorptivity means the amount of
infrared radiation absorbed by each
molecule.
3.3 Analyte means a compound that the
method is intended to measure. This method
is a multi-component method; therefore,
several analytes may be targeted for a given
test.
3.4 Analyte spiking means the process of
quantitatively adding calibration standards to
source effluent. Analyte spiking is used to
evaluate the ability of the sample transport
and FTIR measurement systems to quantify
the target analyte(s).
3.5 Analytical algorithm means the
method used to quantify the concentration of
both target analyte(s) and additional
compounds in a sample matrix that may
introduce analytical interferences in each
FTIR spectrum.
3.6 Analytical interference means a
spectral feature that complicates, and may
even prevent, the analysis of an analyte.
Analytical interferences can be background
or spectral interferences. Background
interferences result from a change in light
throughput relative to the single beam
background. This can be due to factors such
as deposits on reflective surfaces and
windows, temperature changes, a change in
detector sensitivity, a change in infrared
source output, or instrument electronics
failure. Spectral interferences arise due to the
presence of interfering compounds that have
overlapping absorption features with the
analytes of interest.
3.7 Apodization means a mathematical
transformation used to adjust the instrument
line shape for measured peaks. There are
various types of apodization functions; the
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most common are boxcar, triangular, HappGenzel, and Beer-Norton functions.
3.8 Background deviation means a
deviation from 100% transmittance in any
region of the 100% line.
3.9 Background spectrum means a
spectrum taken in the absence of absorbing
species or sample gas matrix, typically
conducted using nitrogen or zero air.
3.10 Bandwidth means the width of a
spectral feature. This width is commonly
listed as the full width at half the maximum
of the spectral feature.
3.11 Beam splitter means a device located
in the interferometer that divides the
incoming infrared radiation into two separate
beams that travel two separate paths before
recombination.
3.12 Calibration transfer standard (CTS)
means a certified gas calibration standard
used to verify instrument stability. For the
purposes of this method, the CTS must be
ethylene, methane, or carbon dioxide. Other
compounds may be used only with
administrator approval.
3.13 Classical least squares (CLS) means
a method of analyzing multicomponent
spectra by scaling reference absorbance
spectra to unknown measured spectra.
3.14 Double beam spectrum means a
transmission or absorbance spectrum derived
by dividing the sample single beam spectrum
by the background spectrum.
Note: The term ‘‘double-beam’’ is used
elsewhere to denote a spectrum in which the
sample and background interferograms are
collected simultaneously along physically
distinct absorption paths. In this method, the
term denotes a spectrum in which the sample
and background interferograms are collected
at different times along the same absorption
path.
3.15 Fourier transform means a
mathematical transform that allows the
conversion of the detector response as a
function of time to intensity as a function of
frequency.
3.16 Fundamental CTS means an NISTtraceable CTS reference spectrum with
known temperature and pressure, that has
been obtained using an absorption cell with
an accurately known optical pathlength.
3.17 Interferogram means a pattern that
contains the effects of the wave interference
that are produced from an interferometer.
3.18 Interferometer means a device used
to produce interference spectra, by dividing
a beam of radiant energy into two or more
paths. One path strikes a fixed mirror, and
the second path strikes a moving mirror
generating an optical path difference that
varies over time between them. The
recombined beams produce constructive and
destructive interference as a function of
changing pathlength. The Michelson
interferometer, used in FTIR instruments,
performs this function.
3.19 Partial least squares means a method
for analyzing multicomponent spectra by
combining features from principal
component and multiple regression analysis.
It has been found to be most useful when
predicting a set of dependent variables from
a large set of independent variables.
3.20 Reference spectra means a spectra of
a pure sample gas obtained at a known
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15109
concentration under controlled conditions of
pressure, temperature, and pathlength.
3.21 Resolution means the minimum
separation that two spectral features must
have to distinguish one feature from the
another.
3.22 Retardation means the optical path
difference between two beams in an
interferometer.
3.23 Run means a series of samples taken
successively from the stack or duct. A test
normally consists of a specific number of
runs.
3.24 Single beam spectrum means the
Fourier transformed interferogram
representing detector response versus
wavenumber.
3.25 Test means the series of runs
required by the applicable regulation.
3.26 Tracer gas means a stable, nonreactive species that is easily transportable
and can be blended in a gas cylinder with a
target analyte to confirm the dilution ratio of
a dynamic spike.
3.27 Transmittance means the amount of
infrared radiation that is not absorbed by the
sample. Percent transmittance is represented
by the following equation: %T = (I/I0) × 100.
4.0 Interferences
Interferences to precise, accurate
measurement using FTIR include both
analytical interferences defined in section 3.6
of this method, and sampling system
interferences. Sampling system interferences
are conditions that prevent analytes from
reaching the instrument due to factors such
as sample line temperature, sample line
materials, condensation, and sample
transport time.
5.0 Safety
This method does not address all potential
safety risks associated with its use. The
hazards of performing this method are those
associated with any stack sampling method.
Anyone performing this method must follow
safety and health practices consistent with
stationary source sampling, including
applicable legal and site-specific safety
requirements. Many HAPs measured by this
method are suspected toxic or hazardous and
may present serious health risks. Exposure to
these compounds from stack gas or from
spiking standards should be avoided. Ensure
safety data sheets (SDS) for gas standards are
available to all personnel using this method.
When using analyte standards, ensure that
gases are properly vented and that the gas
handling system is leak free.
6.0 Equipment and Supplies
The equipment and supplies described in
this section are based on the schematic of the
example sampling system shown in Figure 1.
6.1 Analytical Instrumentation.
6.1.1 Fourier Transform Infrared (FTIR)
Spectrometer. An instrument that collects
and digitizes the spectral interference pattern
from an interferometer and mathematically
transforms this signal into infrared frequency
spectra.
6.1.2 Computer/Data Acquisition System.
A computer with compatible FTIR software
for control of the FTIR system, acquisition of
infrared (IR) data, and analysis of resulting
spectra. This system must have enough data
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storage space to archive all necessary infrared
and meta data (see section 11.6 of this
method).
6.1.3 Gas Absorption Cell. The container
through which the infrared beam interacts
with the sample gas. The gas absorption cell
must have the ability to monitor the pressure
and temperature of the sample gas.
6.2 Sampling System. The sampling
system consists of the components listed in
sections 6.2.1 through 6.2.9 of this method
and validated as detailed in section 9.4.
6.2.1 Sampling Probe. Glass, stainless
steel, polytetrafluoroethane (PTFE), or other
appropriate material to transport analytes to
the IR gas cell. The sampling probe must be
capable of sustained heating to prevent water
condensation and adsorption of analytes.
Note: High stack sample temperatures may
require special steel or cooling of the probe.
For very high moisture sources, it may be
desirable to use a dilution probe. Special
materials or configurations may be required
for probes to traverse ducts or stacks.
6.2.2 Particulate Filters. A glass wool
plug (optional) inserted at the probe tip (for
large particulate removal) and a filter
(required) connected at the outlet of the
heated probe and rated for 99% removal
efficiency of 1 micron aerodynamic
particulate.
6.2.3 Sampling Line. Heated to prevent
sample condensation, and made of stainless
steel, PTFE, or other material that minimizes
adsorption of analytes. Line length should be
the minimum necessary to reach sampling
locations.
6.2.4 Sample Pump. A leak-free pump
with bypass valve, capable of producing a
sample flow rate equal to 5 cell volumes per
sample cycle. The pump may be positioned
upstream or downstream of the FTIR cell. If
the pump is positioned upstream of the
distribution manifold and FTIR system, use
a heated head pump that is constructed from
materials non-reactive with the analytes of
interest.
6.2.5 Gas Distribution Manifold. A
manifold capable of delivering nitrogen or
calibration gases through the sampling
system or directly to the FTIR. The
calibration gas manifold must provide
accurate dilution of the calibration gas as
necessary, monitor calibration gas pressure,
and introduce analyte spikes into the sample
stream (prior to the particulate filter) at a
precise and known flowrate.
6.2.6 Sample Conditioning. An optional
part of the sampling system used to dilute or
remove particulate matter, water vapor, or
other interfering species depending upon the
source matrix composition.
6.2.7 Gas Regulator. A regulator used to
introduce individual gas or gas mixtures from
cylinders. Regulator should be constructed of
the appropriate materials that minimize
analyte adsorption and reaction with the
regulator.
6.2.8 Tubing. PTFE, 316-stainless steel, or
other inert material, of suitable length and
diameter used to connect cylinder regulators
to the gas manifold.
7.0 Reagents and Standards
7.1 Analyte(s) and Tracer Standard Gases.
Analyte(s) and tracer gases must come from
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gas cylinder(s). Criteria pollutants must use
EPA Protocol gases, or equivalent (i.e.,
compressed gas standards with an expanded
uncertainty of ≤2%). All other pollutants
must use ‘‘dual certified’’ compressed gas
standards (i.e., standards certified by two
independent techniques). Target analyte
concentrations should be within ±25% of the
emission source levels or the applicable
compliance limit unless otherwise prescribed
in the applicable standard. If practical, the
analyte standard cylinder shall also contain
the tracer gas at a concentration that gives a
measurable absorbance at a dilution factor of
at least 10:1.
7.2 Calibration Transfer Standard (CTS).
The CTS standard must be NIST-traceable,
per methods specified in the EPA
Traceability Protocol for Assay and
Certification of Gaseous Calibration
Standards, to ±2% of the cylinder tag value.
The CTS standard must be one of the
following gases: ethylene, methane, or carbon
dioxide.
7.3 Chemical Standards. Chemical
standards used to generate reference spectra
must be NIST certified via gravimetric
measurement, or NIST-traceable and vendorcertified accurate to within ±5%.
8.0 Sample Collection, Preservation,
Storage, and Transport
8.1 Pretest Preparations. Determine the
optimum sampling system configuration for
measuring the target analytes. Use available
information to make reasonable assumptions
about moisture content and other
interferences.
8.1.1 Sampling System.
8.1.1.1 Based on the source gas
characteristics (e.g., temperature, pressure
profiles, moisture content, target and
interference physical characteristics, and
particulate concentration), select the
equipment for extracting and transporting gas
samples.
8.1.1.2 Select the techniques and/or
equipment for the measurement of sample
pressures and temperatures in the sample
cell.
8.1.1.3 Heat sample transport lines to
maintain sample temperature at least 10 °F
(5 °C) above the dew point for all sample
constituents. Sample transport lines and
system components must be heated
sufficiently through their entire length to
transport target compounds to the IR sample
cell.
8.1.2 Select Spectroscopic Setup. Select a
spectroscopic configuration for the
application. Approximate the absorption
pathlength, sample pressure, absolute sample
temperature, and signal integration period
necessary for the analysis. Specify the
nominal minimum instrumental linewidth
(MIL) of the system.
8.1.3 Analytical Program.
8.1.3.1 Prepare an analysis algorithm for
acquired spectra. Use as input, reference
spectra of all target analytes and expected
interferents. Include reference spectra of
additional interferent compounds in the
program if their presence (even if transient)
in the samples is considered possible. The
program output must be in ppmv (or parts
per billion by volume [ppbv]) and must
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correct for differences between the reference
pathlength (LR), temperature (TR), and
pressure (PR), and the actual conditions used
for collecting the sample spectra.
8.1.3.2 Choose a mathematical technique
(e.g., classical least squares, partial least
squares, inverse least squares) for analyzing
spectral data by comparison with reference
spectra.
8.1.3.3 Reference spectra incorporated in
the program must either bracket the observed
sample matrix concentration or use a direct
injection to verify the calibration curve.
Additionally, you must use a sufficient
number (>3) of reference spectra (or reference
spectra plus direct injection checks for low
concentration regimes) in the bracketed range
to demonstrate linearity in that concentration
range. Alternatively, if the matrix
concentration is expected to be within three
times the detection limit of this method, you
may use calculated reference spectra (i.e.,
HITRAN or PNNL) at the lower end of the
bracketing range.
8.1.3.4 Analysis regions selected for a
target compound(s) must have an absorbance
value of less than 1. You must select specific
wavelengths in each region where the target
analyte does not overlap with an interfering
compound and use the selected wavelengths
throughout the entire validation (section 9.4),
QA spiking (section 11.4), and testing
campaign.
8.2 Leak Check. To conduct the leak
check, follow the procedures specified in
section 11.1.
8.3 Detector Linearity. To verify detector
linearity, follow the procedures specified in
section 11.2.
8.4 Data Storage Requirements. For these
requirements, follow the procedures
specified in section 11.8.
8.5 Background Spectrum. Flow dry
nitrogen through the gas cell and verify that
no significant amounts of absorbing species
are present. Collect a background spectrum,
using a signal averaging period equal to or
longer than that being used for averaging of
source sample spectra. Assign a unique file
name to the background spectrum.
8.6 Pre-Test Calibrations.
8.6.1 Calibration Transfer Standard. Flow
the CTS gas through the cell and verify that
the measured concentration is stable to
within the uncertainty of the gas standard.
Record the spectrum. Additionally, measure
the linewidth of appropriate CTS band(s) to
verify instrument resolution. Alternatively,
compare CTS spectra to a reference CTS
spectrum, if available, measured at the
nominal resolution.
8.6.2 QA Spike. Conduct a QA spike per
the instructions in section 11.4 of this
method.
8.7 Sampling. See section 11.5 of this
method. While sampling, monitor the signal
transmittance. If the transmittance (relative to
background) changes by 5% or more in any
analytical spectral region, obtain a new
background spectrum.
8.8 Post-Run CTS. After the sampling
run, record another CTS spectrum.
8.9 Perform post-run QA per section 9.1.2
of this method.
9.0 Quality Assurance and Quality Control
9.1 Quality Assurance (QA).
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Mspiked tracer
Mspiked tracer- Mnative tracer
Equation 2
Cnative tracer- Mnative tracer
Where:
Mnative tracer = the measured tracer
concentration present in the native
effluent gas.
Cnative tracer = the undiluted tracer gas
concentration in the cylinder.
ddrumheller on DSK120RN23PROD with PROPOSALS1
Where:
MCspiked = the measured reference analyte
concentration.
MCnative = the measured concentration of the
analyte in the native effluent.
Where:
Cspike = the certified reference analyte
concentration.
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measured upon introduction of the standard
addition (source + SA) via dynamic spike.
Calculate the SAR via the following equation:
Note: Use consistent concentration units
for each variable in Equation 2.
9.3.4.1 Standard Addition Response. The
standard addition response (SAR) represents
the difference between the measured native
source concentration and the concentration
SAR= MCspiked - (1- DF) * MCnative
ESA
In instances where the tracer gas is native
to the source emissions, use the following
equation:
Ctracer spiked = the tracer gas concentration
injected with the spike gas.
Note: Use consistent concentration units
for each variable in Equation 1.
Equation 3
Note: Use consistent concentration units
for each relevant variable in Equation 3.
9.3.4.2 Effective Spike Addition. The
effective spike addition (ESA) is the expected
increase in the measured concentration as a
= DF * (Cspike -
MCnative)
Equation 4
When using a non-certified cylinder, replace
the Cspike term in Equation 4, with
MCspiked.
Note: Use consistent concentration units
for each relevant variable in Equation 4.
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result of injecting a spike. For the section
11.4 QA spike, the ESA must be within 50%
of the native stack concentration. Calculate
the ESA with the following equation, for use
when using a certified cylinder:
9.3.4.3 Spike Recovery. The degree to
which the SAR and the ESA agree represents
the spike recovery (SR), or the ability to
measure the spiked analyte on top of the
amount of that analyte native to the stack.
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EP01MR24.040
DF=
Equation 1
C tracer spiked
Where:
Mspiked tracer = the measured diluted tracer gas
concentration in a spiked sample.
sequence: native gas concentration, SAelevated gas concentration, native gas
concentration. In addition to the pre-test
spike instance, spiking must also be
performed post-test.
9.3.1.2 It is recommended that spiking be
performed after each run to ensure continued
compliance with the required spike recovery
criteria. If spiking is not performed after each
run and the post-test spike fails, all data for
that test are invalid. However, if spiking is
performed after each run, data bracketed on
each end by a successful spike are valid test
data.
9.3.2 Your spike gas flow rate must not
contribute more than 10% of the total
volumetric flow rate through the FTIR.
9.3.3 Determine the response time (RT) of
the system. First, inject zero air into the
system. For standard addition RT
determination, next measure the native stack
concentration of the species to be spiked. The
concentration has stabilized when variability
appears constant for five minutes.
9.3.4 You must determine a dilution
factor (DF) for each dynamic spike.
Determine the DF via a tracer, and use the
following equation for a source where the
tracer is not native to the source emissions:
EP01MR24.038 EP01MR24.039
DF=
the performance requirement of the QA spike
in section 11.4 of this method.
9.3 Spike Procedure. Spiking must be
done per a standard addition procedure
consisting of measuring the source emissions
concentration (i.e., native source gas
concentration), addition of reference gas, and
measurement of the resulting standard
addition (SA) elevated source gas
concentration. Spiking must be done
dynamically accounting for the spike
dilution of sample gas with the addition of
the reference gas.
9.3.1 Each dynamic spike (DS) or SA
replicate consists of a measurement of the
source emissions concentration (native stack
concentration) with and without the addition
of the species of interest. With a single FTIR,
you must alternate the measurement of the
native and SA-elevated source gas so that
each measurement of SA-elevated source gas
is immediately preceded and followed by a
measurement of native stack gas. Introduce
the SA gases in such a manner that the entire
sampling system is challenged. Alternatively,
you may use an independent FTIR and
sampling system to measure the native
source concentration throughout each
standard addition.
9.3.1.1 Pre and post-test spiking must
consist of at least 3 replicates. A replicate is
defined as the following measurement
EP01MR24.037
9.1.1 Pre-Test QA.
9.1.1.1 Prior to testing, verify that the
sample integration time is sufficient to
achieve the required signal-to-noise ratio.
9.1.1.2 Assign a unique file name to each
spectrum.
9.1.1.3 For reporting and recording
requirements, see sections 11.6 and 11.7 of
this method.
9.1.2 Post-Test QA.
9.1.2.1 Inspect the sample spectra
immediately after the run to verify the gas
matrix composition was close to the expected
matrix composition.
9.1.2.2 Verify that the sampling and
instrumental parameters were appropriate for
the actual stack conditions. For example, if
the moisture of the sampled gas was much
higher than anticipated, a shorter pathlength
cell or more dilute sample may be needed.
9.1.2.3 Compare the pre- and post-test
CTS spectra. The peak absorbance in the preand post-test CTS must be ±5% of the mean
value.
9.2 Quality Control (QC). The analyte
spike procedure in section 9.3 of this method
and the validation procedure in section 9.4
of this method are used to evaluate the
performance of the sampling system and to
quantify sampling system effects, if any, on
the measured concentrations. This method is
self-validating provided that the results meet
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Spike recovery is calculated according to the
following equation:
SR=
SAR
ESA
9.3.4.4 Spiking Procedure for Highly
Variable Sources. In some instances, a source
may be encountered that is too variable for
the procedures listed in sections 9.3 and 11.4
of this method. A highly variable source, for
which this procedure may be used is defined
as a source that varies randomly and by more
than 25% from data point to point, where
two consecutive points are less than or equal
to a minute apart. For these types of sources,
the approach outlined in section 9.3.5.4.1 of
this method may be used.
9.3.4.4.1 Dual FTIR and Extractive
Systems Approach. This field approach is
performed using two independent FTIRs and
sample extraction systems that use tubing of
the same length and diameter and that pull
the sample at approximately the same flow
rate. One FTIR characterizes the fluctuations
of the target analyte(s) over time and the
second FTIR performs the spike recoveries.
Note that testers can use either a single probe
attached to both systems or separate probes
for each system with the probe tips co-
Equation 5
located (within 6 inches) in the sample duct.
In either case, it is mandatory for the spike
to occur prior to the PM filter. Perform the
spiking procedure as follows.
Note: This procedure assumes that the
dilution factor is calculated as stated in EPA
Method 320 or ASTM D6348–12e from either
a spectroscopic tracer or metered flows.
9.3.4.4.1.1 After positioning the FTIR
probes accordingly, begin pulling sample gas
into both FTIR sample analysis cells. Use the
same sampling period and the identical
quantification method (i.e., same reference
spectra for construction and the same regions
for quantification) for each FTIR.
a. Sample the source gas stream for
approximately 15 minutes, collecting at least
8 spectra on each FTIR.
b. Calculate the average concentration of
the target analyte(s) for each FTIR. If the
average concentrations determined using the
two FTIRs are not within 10%, either the
analysis routines were not identical, the
timing was not consistent, or the sample
system or FTIR cell in one of the FTIRs is
reacting with the target analyte(s). Note: If the
average concentrations are not within 10%,
the spike recovery criterion will be more
difficult to achieve.
9.3.4.4.1.2 If the average concentrations
agree within 10%, begin flow of the analyte
spike into one of the FTIRs. At this point, the
spiked FTIR should have a consistent offset
to the unspiked FTIR. After this offset is
consistent, collect a minimum of 8 data
points.
9.3.4.4.1.3 Calculate the difference
between the average concentration of the
spiked data and the average concentration of
the unspiked data (i.e., the average
concentration of the spike) using equation 6
of this method.
9.3.4.4.1.4 Calculate the recovery
(equation 7) of the spike using the predicted
spiked concentration by the dilution factor
(as determined per the reference method
used) and the resultant from Step 3 (equation
6).
Equation 6
sv
)
= ( (DF*Spike Cylinder
Concentration)
Where:
SV = Spiked concentration as calculated from
Equation 6.
DF = Dilution Factor as determined from
tracer in spike gas standard or from
flows.
Spike Cylinder Concentration =
Concentration of target analyte(s) from
spike gas standard (e.g., determined from
direct injection or from certified cylinder
tag value).
Note: Use consistent concentration units
for each relevant variable in Equation 7.
9.4 Method Validation Procedure.
This validation procedure, which is based
on EPA Method 301 (40 CFR part 63,
appendix A), must be used to validate this
method for the analytes in a gas matrix.
Analytes that have not been validated for a
particular source type may not be measured
using Method 320. Validation at one source
may also apply to another type of source, if
it can be shown that the exhaust gas
characteristics are similar at both sources.
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p = Number of individual, unspiked
concentration measurements collected.
Note: Use consistent concentration units
for each relevant variable in Equation 6.
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9.4.1 Use section 5.3 of Method 301 (40
CFR part 63, appendix A), the Analyte Spike
procedure, with these modifications. The
statistical analysis of the results follows
section 6.3 of EPA Method 301. Section 3 of
this method defines terms that are not
defined in Method 301.
9.4.2 The analyte spike is performed
dynamically. This means the spike flow is
continuous and constant as spiked samples
are measured.
9.4.3 Introduce the spike gas at the back
of the sample probe.
9.4.4 Spiked effluent is carried through
all sampling components downstream of the
probe.
9.4.5 A single FTIR system (or more) may
be used to collect and analyze spectra (not
quadruplicate integrated sampling trains).
9.4.6 All of the validation measurements
are performed sequentially in a single ‘‘run’’
(section 3.23 of this method).
9.4.7 The measurements analyzed
statistically are each independent (section
3.22 of this method).
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Equation 7
9.4.8 A validation data set must consist of
12 or more spike replicates.
10.0 Calibration and Standardization
10.1 Analytes. Select the required
detection level (DLi) and maximum
permissible analytical uncertainty (AUi) for
each analyte (1 to i). The required DL must
be equal to or greater than the method DL
determined via section 13.1 of this method.
Estimate, if possible, the maximum expected
concentration for each analyte (CMAXi). The
expected measurement range is then
bounded by DLi and CMAXi for each analyte.
10.2 Interferents. List all potential
interferents applicable to your source matrix.
Collect or obtain spectra of known and
suspected interferences that were acquired
using the same optical system that will be
used in the field measurements. You may
also use calculated spectra from sources such
as HITRAN as long as the spectral resolution
matches the resolution of source test sample
spectra. These interferents must be included
in the analytical algorithm used to fit FTIR
spectra for quantitation.
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RecoverY
n = Number of individual spiked
concentration measurements collected.
Up = Individual concentration results from
the unspiked FTIR (native gas
concentration).
EP01MR24.041
Where:
SV = Concentration of target analyte spiked
into the extracted gas stream.
Si = Individual concentration results from the
spiked FTIR.
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10.3 CTS Absorption Bands. Absorption
bands used for CTS quantitation must be at
least ten times the root mean square (RMS)
value of the noise equivalent absorbance
(NEA) of a wavelength range nearest to that
absorption band. This value, NEARMSCTS can
be determined as follows:
NEAcrs
_
RMS -
10.3.1 Determine the absolute noise
equivalent absorption (NEA) for an analytical
region by flowing nitrogen or zero air through
the gas sample cell. The NEA is the peak-topeak noise in a spectrum resulting from
collection of two successive background
spectra. Therefore, collect two background
spectra in succession while the nitrogen or
zero air is continuously flowing through the
cell. Note that the same averaging time must
be used for NEA determination as will be
used for actual sample collection.
10.3.2 Calculate NEARMSCTS per the
following equation:
.!:. ~f1:crs(NEAqrs)2
n,t.,J=l
Equation 8
l
Where:
NCTS = the number of absorbance points in
the analysis region for the CTS.
NEAiCTS = the individual absorbance values
of the noise spectrum in the analysis
region, i.
10.4 Reference Spectra. Obtain reference
spectra for each analyte, interferant,
surrogate, CTS, and tracer.
10.4.1 The tester must report traceability
and other pertinent information for each
reference spectrum, for each compound,
including: temperature, pressure,
concentration, cylinder source and
specifications, spectral regions of analysis
used for quantitation (with specific
wavelength ranges used), and calibration fit
equations and correlations.
10.4.2 If commercially prepared, or other
available reference libraries are used to
quantify data, the FTIR spectral resolution
and line position, cell pathlength,
temperature and pressure, and apodization
function must be known and reported.
Resolution, line position, and apodization
function used for collection of sample spectra
must be the same as those of the reference
spectra used for quantitation.
10.4.3 Reference spectra for each target
compound must bracket the concentration of
that compound in the sample stream.
10.4.3.1 In the case where traceable
reference spectra provided by the FTIR
manufacturer do not bracket the
concentration of a particular compound, two
15113
options are available. A direct injection of the
compound of interest (NIST traceable and
certified to ±5%) into the FTIR at a
concentration lower than that found in the
sample stream and within three times the
method detection level, may be performed to
demonstrate the appropriateness of the
calibration line at this level. To perform this
check, while directly injecting the compound
of interest into the FTIR, wait for the
concentration of the compound to stabilize.
Once stable, verify that the concentration as
determined via the calibration curve is
within 10% of the cylinder value or else do
not proceed with testing.
10.4.3.2 Alternatively, calculated spectra,
such as those from HITRAN or PNNL, may
be used at the lower end of the bracketing
range, within three times the method
detection level, as well.
10.4.4 Collecting Reference Spectra. In
some cases, it may be necessary for the tester
to collect reference spectra prior to testing.
The procedure found in this section is to be
used in such a case.
10.4.4.1 Record a set of CTS spectra.
10.4.4.2 Collect a set of the reference
spectra at two or more concentrations in
triplicate over the desired concentration
range. The top of the concentration range
must be less than 10 times that of the bottom
of the range.
10.4.4.3 Collect a second set of CTS
spectra. The maximum accepted
concentration for each compound shall be
higher than the maximum estimated
concentration for both analytes and known
interferents in the effluent gas. For each
analyte, the minimum accepted
concentration shall be no greater than ten
times the concentration-pathlength product
of that analyte at its required detection limit.
10.4.4.4 Permanently store the
background and interferograms digitally, and
separately. Document details of the
mathematical process (i.e., apodization
function) for generating the spectra from
these interferograms. Record sample pressure
(Pr), sample temperature (Tr), reference
absorption pathlength (Lr), and interferogram
signal integration period (tsr).
10.5 Absorption Cell Path Length
Determination.
10.5.1 Flow the CTS through the FTIR
cell. Once the absorbance of two consecutive
spectra differ by less than or equal to the
uncertainty of the cylinder standard, the CTS
spectrum may be recorded. Note that the CTS
gas must be one of the following gases:
ethylene, methane, or carbon dioxide.
10.5.2 Record a set of the absorption
spectra of the CTS, and record the
temperature, pressure, and concentration of
the CTS.
10.5.3 Record the instrument
manufacturer’s nominal absorption
pathlength, nominal spectral resolution, and
the CTS signal integration period.
10.5.4 Calculate the reference cell
absorption pathlength, according to the
following equation:
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10.6 Instrument Resolution.
10.6.1 Flow ambient air through the gas
cell.
10.6.2 Verify the instrument resolution
using a water absorbance peak near either
1,918 cm¥1, 3,050 cm¥1, or 3,920 cm¥1.
10.6.3 The absorbance of the peak being
used for the resolution determination should
be approximately 0.25 absorbance units. Mix
additional humified air or nitrogen with the
ambient flow, to achieve this absorbance.
10.6.4 Record an absorbance spectrum
and measure the FWHH of the chosen water
peak. The measured FWHH of the water peak
must be within 5% of the nominal
instrument resolution to proceed with
testing.
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11.0
Method Procedures
11.1 Leak Check. Verify that there are no
significant vacuum-side leaks using one of
the leak tests described in this section.
Perform the vacuum-side leak check after
each installation at the sampling or
measurement location. Leak check must be
performed prior to the start of the field test,
and after any relocation or maintenance to
the sample transport system. A leak may be
detected either by measuring a small amount
of flow when there should be zero flow, or
by measuring the vacuum decay rate. To test
for leaks using loss of vacuum you must
know the vacuum-side volume of your
sampling system to within ±10% of its true
volume.
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Where:
Lr = reference cell absorption pathlength.
Lf = fundamental CTS absorption pathlength.
Tr = absolute temperature of reference CTS
gas.
Tf = absolute temperature of fundamental
CTS gas.
Pr = absolute pressure of reference CTS gas.
Pf = absolute pressure of fundamental CTS
gas.
Cr = concentration of the reference CTS gas.
Cf = concentration of the fundamental CTS
gas.
{Ar/Af} = ratio of the reference CTS
absorbance to the fundamental CTS
absorbance, determined by classical least
squares, integrated absorbance area,
spectral subtraction, or peak absorbance
techniques.
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11.1.1 Low-Flow Leak Test. Test a
sampling system for leaks using low-flow
measurements as follows:
11.1.1.1 Seal the probe end of the system
by capping or plugging the end of the sample
probe.
11.1.1.2 Start sampling pumps and
operate them until the pressure stabilizes.
11.1.1.3 Observe/measure the flow
through the vacuum-side of the sampling
system. A flow of less than 0.5% of the
system’s normal in-use flow rate is
acceptable.
Note: For bypass systems, where the
sample flow rate through the vacuum side of
the sample system is greater than the FTIR
cell flow rate, the higher flow rate (bypass
plus analyzer/FTIR flow rate) is used as the
in-use flow rate when calculating
acceptability of the leak level.
11.1.2 Vacuum-Decay Leak Test. Perform
a vacuum-decay leak test as follows:
11.1.2.1 Seal the probe end of the system
as close to the probe opening as possible by
capping or plugging the end of the sample
probe.
11.1.2.2 Operate all vacuum pumps.
Draw a vacuum on the sampling system and
let the pressure on the system stabilize.
11.1.2.3 Turn off the sample pumps and
seal the system under a vacuum of 250
mmHg greater than the source static pressure.
Record the absolute pressure and the system
absolute temperature every 30 seconds for 5
minutes. The leak rate must be equal to or
less than 2.5 mmHg per minute.
11.2 Detector Linearity. Observe the
single beam instrument response in the
frequency region below the detector cutoff
(usually <400 cm¥1), where the detector
response is known to be zero. Verify that the
detector response is ‘‘flat’’ and equal to zero
in this region, or at least 100 times less than
the peak signal in the entire spectrum. If the
response is not linear, decrease the aperture
or attenuate the IR beam, and repeat the
linearity check until the detector response is
linear.
11.3 Gas Cell Pathlength. Verify the gas
cell pathlength of your instrument by
following the procedure found in section
10.6.4 of this method.
11.4 QA Spike. This procedure assumes
that the method has been validated for each
of the target analytes at the source. Choose
one of two options and perform the standard
addition procedure listed in ection 9.3 of this
method.
Note: For unstable sources, QA spiking
may be difficult. An alternative procedure for
such a source is described in section 9.3.5.4.
11.4.1 QA Spike Option 1. Use a certified
standard (±2% accuracy) for an analyte that
has been validated at the source. One may
either spike each analyte of interest or choose
an appropriate surrogate. An appropriate
surrogate must have a vapor pressure that is
less than or equal to the analyte of interest
and be less soluble in water. The wavelength
at which the surrogate is to be quantified
must be reported and be within 100
wavenumbers of a wavenumber that will be
used to quantify the analyte of interest.
Additionally, the pKa of a surrogate must be
within 20% of the pKa of the analyte of
interest. Surrogates are not allowed for the
following analytes: formaldehyde, HCl, HF,
NH3, and vinyl chloride. If the spike
recovery, as calculated by Equation 5 of this
method, is within 70–130% then proceed
with the testing.
11.4.2 QA Spike Option 2. Use a noncertified cylinder for an analyte that has been
validated at the source. As with Option 1,
one may either spike each analyte of interest
or choose an appropriate surrogate. If the
spike recovery, as calculated by equation 5 of
this method, is within 90–110%, then
proceed with the testing.
11.5 Sampling. Sampling must be done
using a continuous flow of source gas.
11.5.1 Stratification Check. A
stratification check must be performed, per
the steps in this section, to justify sampling
at a single location during testing.
11.5.1.1 Use a probe of appropriate length
to measure the analyte of interest at each of
12 traverse points (MNi, where i = 1 to 12)
located according to section 11.3 of Method
1 in appendix A–1 to 40 CFR part 60 for a
circular stack or nine points at the centroids
of similarly shaped, equal area divisions of
the cross section of a rectangular stack.
11.5.1.2 Calculate the mean measured
concentration for all sampling points
(MNavg).
11.5.1.3 Calculate the percent
stratification (St) of each traverse point using
the following equation:
11.5.1.4 The gas stream is considered to
be unstratified and you may perform testing
at a single point that most closely matches
the mean if the concentration at each traverse
point differs from the mean concentration for
all traverse points by no more than 5.0% of
the mean concentration.
11.5.1.5 If the criteria for single point
sampling is not met, but the concentration at
each traverse point differs from the mean
concentration by no more than 10% of the
mean, the gas stream is considered minimally
stratified, and you may sample using the ‘‘3point short line.’’
11.5.1.6 If the concentration at any
traverse point differs from the mean by more
than 10%, the gas stream is considered
stratified, and you must sample using the
stratification check procedure specified in
section 11.5.1.1 of this method.
11.5.2 Assign a unique filename to each
spectrum and separately to each
corresponding interferogram. Spectra and
interferograms must be providable in ‘‘.spc’’
format upon request.
11.5.3 Temperature. The temperature of
the gas cell must be measured directly. The
temperature measurement device must be
calibrated to within ±0.1 °C every 12 months.
11.5.4 Pressure. The gas cell pressure
must be measured empirically. The
measurement device must be calibrated to
within ±1 mmHg every 12 months.
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11.5.5 Inspect the sample spectra
immediately after the run to verify that the
gas matrix composition was close to the
expected (assumed) gas matrix. Additionally,
look at the residual spectra for each sample
spectrum to confirm interferences have been
accounted for.
11.6 Post-Test CTS. At the end of each
test, record another CTS spectrum. Compare
the pre- and post-test CTS spectra. The peak
absorbance in pre- and post-test CTS must be
±5% of the mean value.
11.7 Record and Report.
11.7.1 The following must be
documented and reported for each sample
spectrum: sampling conditions, sampling
time (# of scans per average and amount of
time per scan), instrumental conditions
(pathlength, temperature, pressure,
resolution, laser frequency, instrument make
and model), and spectral filename.
11.7.2 Test Report. You must prepare a
test report following the guidance in EPA
Guidance Document 043 (Preparation and
Review of Test Reports. December 1998).
Additional minimum reporting requirements
are listed here:
11.7.2.1 Instrument and sampling system
related items.
a. Instrument make and model.
b. Sampling line length, material, and
temperature.
c. Instrument resolution.
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d. Cell pathlength, pressure, and
temperature.
e. Laser frequency.
f. Cylinder regulator type.
11.7.2.2 Software/Algorithm related
items.
a. Gases included in the analysis
(interferences + analytes of interest).
b. Concentration values of reference
spectra, as well as temperature and pressure.
information for all interferences and analytes
of interest.
c. Analysis wavelength regions for each
compound (interferences + analytes of
interest).
11.7.2.3 CTS, QA/QC and validation
related items.
a. A list of compounds that are being
spiked. Note that Method 320 allows for use
of qualified surrogates. Qualified surrogates
should be appropriate for the compound
actually being measured. It is preferable that
the compound of interest always be spiked if
it is available as a certified standard.
b. Is/are the spike(s) being performed
dynamically?
c. Are spikes being introduced at the back
of the sample probe and travelling through
the entire sampling system?
d. Are standards being used for QA spiking
of appropriate quality? For example, (±2% for
Protocol gases where available and ±5% for
other certified gases?
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e. Has FTIR been validated for the source
under consideration?
11.8 Digital Data Storage. All field test
data must be electronically stored, readily
available, and provided to the regulatory
authority upon request. Stored information
must include: sample interferograms,
background interferograms, CTS sample
interferograms, processed sample absorbance
spectra, and processed CTS absorbance
spectra.
12.0
Ccorr =
12.1.2 The algorithm must be capable of
reporting spectral residuals for all
compounds being analyzed as a function of
its spectral fit using the techniques in section
11.1 of this method.
13.0 Method Performance
13.1 Detection Level (DL). The DL of this
method is defined as the SAR value where
the SAR is greater than three times the
residual value of the corresponding standard
addition elevated concentration (MCspiked).
The DL for this method must be less than or
equal to 20% of the applicable compliance
limit for the compound being measured. If
this is not the case, Method 320 cannot be
used for such an application.
13.2 Background Deviation. Deviations in
absorption greater than ±5% in an analytical
region are unacceptable, and Method 320
cannot be used under this condition.
• !!'!!...
Data Analysis and Calculations
12.1 Analyte concentrations must be
measured using reference spectra as they are
described in section 10.5 of this method. Use
the algorithm developed in section 8.3 of this
method to calculate the concentration of each
species in the sample matrix as well as their
C:) (;;) (::)
14.0
Ccalc
respective residuals. Classical least squares,
augmented classical least squares, or partial
least squares algorithms must meet the
following criteria:
12.1.1 The algorithm must be capable of
correcting for differences in gas cell
pathlength, temperature, and cell pressure
between sample and reference spectra. If the
algorithm does not have this capability,
perform this correction using equation 12:
Equation 12
16.0
Pollution Prevention
The extracted sample gas is vented outside
the enclosure containing the FTIR system
and gas manifold after the analysis. In typical
method applications, the vented sample
volume is a small fraction of the source
volumetric flow and its composition is
identical to that emitted from the source.
When analyte spiking is used, spiked
pollutants are vented with the extracted
sample gas. Minimize emissions by keeping
the spike flow off when not in use.
15.0
15115
Waste Management
Small volumes of laboratory gas standards
can be vented through a laboratory hood.
Neat samples must be packed and disposed
of according to applicable regulations.
Surplus materials may be returned to
supplier for disposal.
References
1. Protocol for the Use of Extractive Fourier
Transform Infrared (FTIR) Spectrometry in
Analyses of Gaseous Emissions from
Stationary Sources, https://www3.epa.gov/
ttn/emc/ftir/FTIRProtocol.pdf.
2. U.S. EPA. Method 301—Field Validation
of Pollutant Measurement Methods from
Various Waste Media, 40 CFR part 63,
appendix A.
3. EPA Traceability Protocol for Assay and
Certification of Gaseous Calibration
Standards, https://www.epa.gov/airresearch/epa-traceability-protocol-assayand-certification-gaseous-calibrationstandards.
17.0 Tables, Diagrams, Flowcharts, and
Validation Data
....
...........
...,~
-.,
~~
*
*
*
*
EP01MR24.048
Figure 1. Schematic of FTIR Sampling
System
*
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.:.1.........
Agencies
[Federal Register Volume 89, Number 42 (Friday, March 1, 2024)]
[Proposed Rules]
[Pages 15101-15115]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-04359]
-----------------------------------------------------------------------
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 63
[EPA-HQ-OAR-2022-0491; FRL-9992-01-OAR]
RIN 2060-AV81
EPA Method 320--Measurement of Vapor Phase Organic and Inorganic
Emissions by Extractive Fourier Transform Infrared (FTIR) Spectroscopy
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
-----------------------------------------------------------------------
SUMMARY: This action proposes editorial and technical revisions to the
Environmental Protection Agency's (EPA's) Method 320 (Measurement of
Vapor Phase Organic and Inorganic Emissions by Extractive Fourier
Transform Infrared (FTIR) Spectroscopy). The proposed revisions include
updating the validation and quality assurance (QA) spiking procedures
of the method to provide a more performance-based approach with
specified acceptance criteria. The proposed revisions will provide
flexibility to the stack testing community while ensuring consistent
implementation and quality of the measurement results across emissions
sources and facilities.
DATES: Comments. Comments must be received on or before April 30, 2024.
Public Hearing. The EPA will hold a virtual public hearing on March
29, 2024 if a request for a virtual public hearing is received on or
before March 8, 2024. Refer to the SUPPLEMENTARY INFORMATION section
for additional information on the virtual public hearing.
ADDRESSES: You may submit comments, identified by Docket ID No. EPA-HQ-
OAR-2022-0491, by any of the following methods:
Federal eRulemaking Portal: https://www.regulations.gov/
(our preferred method). Follow the online instructions for submitting
comments.
Email: [email protected]. Include Docket ID No. EPA-
HQ-OAR-2022-0491 in the subject line of the message.
Fax: (202) 566-9744. Attention Docket ID No. EPA-HQ-OAR-
2022-0491.
Mail: U.S. Environmental Protection Agency, EPA Docket
Center, Docket ID No. EPA-HQ-OAR-2022-0491, Mail Code 28221T, 1200
Pennsylvania Avenue NW, Washington, DC 20460.
Hand/Courier Delivery: EPA Docket Center, WJC West
Building, Room 3334, 1301 Constitution Avenue NW, Washington, DC 20004.
The Docket Center's hours of operation are 8:30 a.m.--4:30 p.m.,
Monday--Friday (except Federal Holidays).
Instructions: All submissions received must include the Docket ID
No. for this rulemaking. Comments received may be posted without change
to https://www.regulations.gov/, including any personal information
provided. For detailed instructions on sending comments and additional
information on the rulemaking process, see the ``Public Participation''
heading of the SUPPLEMENTARY INFORMATION section of this document.
FOR FURTHER INFORMATION CONTACT: Dr. David Nash, Office of Air Quality
Planning and Standards, Air Quality Assessment Division (E143-02),
Environmental Protection Agency, Research Triangle Park, NC 27711;
telephone number: (919) 541-9425; fax number: (919) 541-0516; email
address: [email protected].
SUPPLEMENTARY INFORMATION:
Preamble acronyms and abbreviations. Throughout this document, the
use of ``we,'' ``us,'' or ``our'' is intended to refer to the EPA. We
use multiple acronyms and terms in this preamble. While this list may
not be exhaustive, to ease the reading of this preamble and for
reference purposes, the EPA defines the following terms and acronyms
here:
ASTM American Society for Testing and Materials
CAA Clean Air Act
CBI Confidential Business Information
CFR Code of Federal Regulations
CTS calibration transfer standard
EPA Environmental Protection Agency
FTIR Fourier Transform Infrared
FTP File Transfer Protocol
IR infrared
NAICS North American Industry Classification System
NESHAP National Emissions Standards for Hazardous Air Pollutants
NIST National Institute of Standards and Technology
NSPS New Source Performance Standards
NTTAA National Technology Transfer and Advancement Act
OAQPS Office of Air Quality Planning and Standards OMB Office of
Management and Budget
PRA Paperwork Reduction Act
PTFE polytetrafluoroethane
QA quality assurance
RFA Regulatory Flexibility Act
SF6 sulfur hexafluoride
TTN Technology Transfer Network
UMRA Unfunded Mandates Reform Act
VCS Voluntary Consensus Standard
WJC William Jefferson Clinton
[micro]m micron
Organization of this document. The information in this preamble is
organized as follows:
I. General Information
A. Does this action apply to me?
B. Where can I get a copy of this document and other related
information?
II. Public Participation
A. Written Comments
B. Participation in Virtual Public Hearing
III. Background
IV. Summary of Proposed Revisions to Method 320
A. Section 1.0 (Introduction)
B. Section 2.0 (Summary of Method)
C. Section 3.0 (Definitions)
D. Section 4.0 (Interferences)
[[Page 15102]]
E. Section 5.0 (Safety)
F. Section 6.0 (Equipment and Supplies)
G. Section 7.0 (Reagents and Standards)
H. Section 8.0 (Sampling and Analysis Procedure)
I. Section 9.0 (Quality Control)
J. Section 10.0 (Calibration and Standardization)
K. Section 11.0 (Data Analysis and Calculations)
L. Section 12.0 (Method Performance Data Analysis and
Calculations)
M. Section 13.0 (Method Validation Procedure)
N. Section 14.0 (Pollution Prevention)
O. Section 15.0 (Waste Management)
P. Section 16.0 (References)
Q. New Section 17.0 (Tables, Diagrams, Flowcharts, and
Validation Data)
R. Addendum To Test Method 320
IV. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory Planning and Review and
Executive Order 14094: Modernizing Regulatory Review
B. Paperwork Reduction Act (PRA)
C. Regulatory Flexibility Act (RFA)
D. Unfunded Mandates Reform Act (UMRA)
E. Executive Order 13132: Federalism
F. Executive Order 13175: Consultation and Coordination With
Indian Tribal Governments
G. Executive Order 13045: Protection of Children From
Environmental Health Risks and Safety Risks
H. Executive Order 13211: Actions That Significantly Affect
Energy Supply, Distribution, or Use
I. National Technology Transfer and Advancement Act (NTTAA)
J. Executive Order 12898: Federal Actions To Address
Environmental Justice in Minority Populations and Low-Income
Populations and Executive Order 14096: Revitalizing Our Nation's
Commitment to Environmental Justice for All
I. General Information
A. Does this action apply to me?
The proposed amendments to Method 320 apply to industries that are
subject to certain provisions of 40 CFR parts 60 and 63. The source
categories and entities potentially affected are listed in table 1 of
this preamble. This table is not intended to be exhaustive, but rather
provides a guide for readers regarding entities likely to be regulated
by this action. This table lists the types of entities that EPA is now
aware could potentially be affected by this action. Other types of
entities not listed in the table could also be regulated.
Table 1--Potentially Affected Source Categories
------------------------------------------------------------------------
Examples of regulated
Category NAICS \a\ entities
------------------------------------------------------------------------
Industry...................... 321211........... Plywood and Composite
Wood Products.
324110........... Petroleum Refineries.
325211........... Polyvinyl Chloride
and Copolymers
Production.
327410........... Lime Manufacturing
Plants.
333242........... Semiconductor
Manufacturing.
562211........... Hazardous Waste
Combustors.
327993........... Mineral Wool
Production.
322120........... Kraft Pulp and Paper
Mills.
2211, 48621, Stationary
92811, 211111, Reciprocating
211112, and Internal Combustion
622110. Engines.
------------------------------------------------------------------------
\a\ North American Industry Classification System (2022).
If you have any questions regarding the applicability of the
proposed changes to Method 320, contact the person listed in the
preceding FOR FURTHER INFORMATION CONTACT section.
B. Where can I get a copy of this document and other related
information?
The docket number for this action is Docket ID No. EPA-HQ-OAR-2022-
0491. In addition to being available in the docket, an electronic copy
of the proposed method revisions is available on the Technology
Transfer Network (TTN) website at https://www3.epa.gov/ttn/emc/methods/. The TTN provides information and technology exchange in
various areas of air pollution control.
II. Public Participation
A. Written Comments
Submit your comments, identified by Docket ID No. EPA-HQ-OAR-2022-
0491, at https://www.regulations.gov (our preferred method), or the
other methods identified in the ADDRESSES section. Once submitted,
comments cannot be edited or removed from the docket. The EPA may
publish any comment received to its public docket. Do not submit to
EPA's docket at https://www.regulations.gov any information you
consider to be Confidential Business Information (CBI), Proprietary
Business Information (PBI), or other information whose disclosure is
restricted by statute. Multimedia submissions (audio, video, etc.) must
be accompanied by a written comment. The written comment is considered
the official comment and should include discussion of all points you
wish to make. The EPA will generally not consider comments or comment
contents located outside of the primary submission (i.e., on the web,
cloud, or other file sharing system). Please visit https://www.epa.gov/dockets/commenting-epa-dockets for additional submission methods; the
full EPA public comment policy; information about CBI, PBI, or
multimedia submissions; and general guidance on making effective
comments.
B. Participation in Virtual Public Hearing
If a request for a virtual public hearing is received on or before
March 8, 2024 the EPA will hold a virtual public hearing on March 29,
2024. To request a virtual public hearing or to register to speak at
the virtual hearing, please contact Mr. David Nash at (919) 541-9425 or
[email protected]. The last day to pre-register to speak at the hearing
will be March 22, 2024. On March 26, 2024, the EPA will post a general
agenda for the hearing that will list pre-registered speakers in
approximate order at: https://www3.epa.gov/ttn/emc/methods.
The EPA encourages commenters to provide the EPA with a copy of
their oral testimony electronically by emailing it to Mr. David Nash at
[email protected]. The EPA also recommends submitting the text of your
oral comments as written comments to the rulemaking docket.
The EPA may ask clarifying questions during the oral presentations
but will not respond to the presentations at that time. Written
statements and supporting information submitted during the comment
period will be considered with the same weight as oral comments and
supporting information presented at the public hearing.
Please note that any updates made to any aspect of the hearing are
posted online at https://www3.epa.gov/ttn/
[[Page 15103]]
emc/methods. The EPA does not intend to publish a document in the
Federal Register announcing updates.
III. Background
Method 320 describes the procedures for the measurement of vapor
phase organic and inorganic emissions by Fourier Transform Infrared
(FTIR) spectroscopy. The EPA promulgated Method 320 along with the
National Emissions Standards for Hazardous Air Pollutants (NESHAP) for
Portland Cement Manufacturing Industry (40 CFR part 63, subpart LLL) on
June 14, 1999 (64 FR 31898) under section 112 of the Clean Air Act
(CAA) as amended. Since promulgation, the EPA has incorporated the use
of Method 320 for demonstrating compliance with emissions standards
into numerous NESHAP and New Source Performance Standards (NSPS).
Over the 24-year period since promulgation, the use of FTIR
spectroscopy has evolved as testing contractors, analytical
laboratories, the EPA, and State entities have developed new standard
operating procedures and methods to reflect improvements in sampling
and analytical techniques. In 2017, the EPA held a series of informal
discussions with stakeholders in the measurement community to identify
technical issues related to measuring emissions using FTIR spectroscopy
and potential revisions to Method 320. The stakeholders consisted of a
cross-section of interested parties including representatives from
State regulatory entities, various EPA offices, analytical
laboratories, emission testing firms, analytical standards vendors,
instrument vendors, and others with experience in FTIR spectroscopy and
Method 320. The docket for this action contains summaries of the
stakeholder discussions.
IV. Summary of Proposed Revisions to Method 320
In this action, the EPA proposes technical revisions that update
the validation and quality assurance (QA) spiking procedures of Method
320 to provide a more performance-based approach. The proposed
revisions would more closely align Method 320 with the EPA's approach
to emissions measurement, which emphasizes specifying performance-based
criteria in test methods. Instead of specifying exactly how stack
testers should use or perform a particular method procedure, the method
defines the criteria that must be met for a specific method element,
which provides stack testers with flexibility while maintaining the
quality and reliability of the measurement results. The EPA is also
proposing technical revisions and editorial changes to clarify and
update the requirements and procedures specified in Method 320,
including removing the batch sampling procedures.
A. Section 1.0 (Introduction)
In this action, the EPA proposes to revise the name of section 1.0
from ``Introduction'' to ``Scope and Application,'' to update the
introductory paragraph to remove references to the FTIR Protocol, and
to remove the note regarding use of sample conditioning systems. The
EPA also proposes to renumber and update sections 1.1.1 (Analytes) and
1.1.2 (Applicability) to sections 1.1 and 1.2, respectively, and to
replace the existing sections 1.2 (Method Range and Sensitivity), 1.3
(Sensitivity), and 1.4 (Data Quality) with a revised section 1.3 (Data
Quality Objectives).
B. Section 2.0 (Summary of Method)
In this action, the EPA proposes to update section 2.0 by revising
sections 2.1 (Principle) and 2.2 (untitled) and removing sections 2.3
(Reference Spectra Availability) and 2.4 (Operator Requirements). In
section 2.1, the EPA proposes to remove the title and consolidate
sections 2.1.1 through 2.1.5 and the introductory paragraph to section
2.2 (Sampling and Analysis) into a single paragraph. In section 2.2,
the EPA also proposes to remove the discussion of Beer's Law in section
2.2.1 and to update the references to method evaluation and validation
and pre-test procedures.
C. Section 3.0 (Definitions)
In this action, the EPA proposes to remove the following
definitions for technical terms that are not needed in the proposed
Method 320 and for terms commonly used in the emissions measurement
community for which a definition is unnecessary:
Batch Sampling.
Concentration.
Continuous Sampling.
Emissions Test.
Gas Cell.
Independent Sample.
Interferant.
Measurement.
One Hundred Percent Line.
Quantitation Limit.
Reference Calibration Transfer Standard (CTS).
Root Mean Square Difference.
Sample Analysis.
Sampling Resolution.
Sampling System.
Screening.
Sensitivity.
Standard Spectrum.
Surrogate.
Test CTS.
Truncation.
Zero Filling.
Validation.
Validation Run.
The EPA also proposes revisions to five definitions currently used
in Method 320. Table 2 of this preamble presents the proposed revisions
for each definition.
Table 2--Proposed Revisions to Existing Definitions
------------------------------------------------------------------------
Term Revision Proposed definition
------------------------------------------------------------------------
Analyte..................... Clarify that Method Analyte means a
320 can measure compound that the
more than one method is intended
analyte per test. to measure. This
method is a multi-
component method;
therefore, several
analytes may be
targeted for a
given test.
Background Deviation........ Move the performance Background deviation
criteria from the means a deviation
definition to from 100%
revised section transmittance in
13.2 (Background any region of the
Deviation). 100% line.
CTS [Calibration Transfer Update the Calibration transfer
Standard] Standard. definition to standard (CTS)
remove the means a certified
redundant gas calibration
``standard'' in the standard used to
term and to specify verify instrument
the acceptable CTS stability. For the
gases. purposes of this
method, the CTS
must be ethylene,
methane, or carbon
dioxide. Other
compounds may be
used only with the
Administrator's
approval.
[[Page 15104]]
Reference Spectrum.......... Change the term to Reference spectra
plural (i.e., means a spectra of
``Reference a pure sample gas
Spectra''), clarify obtained at a known
the definition, and concentration under
remove the controlled
reference to the conditions of
FTIR Protocol. pressure,
temperature, and
pathlength.
Run......................... Replace Run means a series
``measurements'' of samples taken
with ``samples'' successively from
and remove the the stack or duct.
minimum requirement A test normally
specifications. consists of a
specific number of
runs.
------------------------------------------------------------------------
The EPA also proposes to add definitions for the key technical
terms shown in table 3 of this preamble to improve the clarity of the
principles and procedures used in Method 320.
Table 3--Proposed New Definitions
------------------------------------------------------------------------
Term Proposed definition
------------------------------------------------------------------------
Absorbance................... The negative logarithm of transmission
represented by the relationship A = -
log(I/I0), where I is the transmitted
intensity of light, and I0 is the
incident intensity of light upon a
molecule.
Absorptivity................. The amount of infrared radiation absorbed
by each molecule.
Analyte Spiking.............. The process of quantitatively adding
calibration standards to source
effluent. Analyte spiking is used to
evaluate the ability of the sample
transport and FTIR measurement systems
to quantify the target analyte(s).
Analytical Algorithm......... The method used to quantify the
concentration of both target analyte(s)
and additional compounds in a sample
matrix that may introduce analytical
interferences in each FTIR spectrum.
Analytical Interference...... A spectral feature that complicates, and
may even prevent, the analysis of an
analyte. Analytical interferences can be
background or spectral interferences.
Background interferences result from a
change in light throughput relative to
the single beam background. This can be
due to factors such as deposits on
reflective surfaces and windows,
temperature changes, a change in
detector sensitivity, a change in
infrared source output, or instrument
electronics failure. Spectral
interferences arise due to the presence
of interfering compounds that have
overlapping absorption features with the
analytes of interest.
Apodization.................. A mathematical transformation that is
used to adjust the instrument line shape
for measured peaks. There are various
types of apodization functions; the most
common are boxcar, triangular, Happ-
Genzel, and Beer-Norton functions.
Background Spectrum.......... A spectrum taken in the absence of
absorbing species or sample gas matrix,
typically conducted using nitrogen or
zero air.
Bandwidth.................... The width of a spectral feature. This
width is commonly listed as the full
width at half the maximum of the
spectral feature.
Beam Splitter................ A device located in the interferometer
that divides the incoming infrared
radiation into two separate beams that
travel two separate paths before
recombination.
Classical Least Squares...... A method of analyzing multicomponent
spectra by scaling reference absorbance
spectra to unknown measured spectra.
Double Beam Spectrum......... A transmission or absorbance spectrum
derived by dividing the sample single
beam spectrum by the background
spectrum.
Fourier Transform............ A mathematical transform that allows the
conversion of the detector response as a
function of time to intensity as a
function of frequency.
Fundamental CTS.............. An NIST-traceable CTS reference spectrum
with known temperature and pressure that
has been obtained using an absorption
cell with an accurately known optical
pathlength.
Interferogram................ A pattern that contains the effects of
the wave interference that are produced
from an interferometer.
Interferometer............... A device used to produce interference
spectra, by dividing a beam of radiant
energy into two or more paths. One path
strikes a fixed mirror and the second
path strikes a moving mirror generating
an optical path difference that varies
over time between them. The recombined
beams produce constructive and
destructive interference as a function
of changing pathlength. The Michelson
interferometer, used in FTIR
instruments, performs this function.
Partial Least Squares........ A method for analyzing multicomponent
spectra by combining features from
principal component and multiple
regression analysis. It has been found
to be most useful when predicting a set
of dependent variables from a large set
of independent variables.
Resolution................... The minimum separation that two spectral
features must have to distinguish one
feature from the another.
Retardation.................. The optical path difference between two
beams in an interferometer.
Single Beam Spectrum......... The Fourier transformed interferogram
representing detector response versus
wavenumber.
Test......................... The series of runs required by the
applicable regulation.
Tracer Gas................... A stable, non-reactive species that is
easily transportable and can be blended
in a gas cylinder with a target analyte
to confirm the dilution ratio of a
dynamic spike.
Transmittance................ The amount of infrared radiation that is
not absorbed by the sample. Percent
transmittance is represented by the
following equation: %T = (I/I0) x 100.
------------------------------------------------------------------------
D. Section 4.0 (Interferences)
In section 4.0 (Interferences), the EPA proposes to consolidate
sections 4.1 (Analytical Interferences) and 4.2 (Sampling System
Interferences) into revised section 4.0 and to incorporate the
discussion of background and spectral interferences in sections 4.1.1
and 4.1.2, respectively, into the
[[Page 15105]]
definition of ``Analytical Interference.'' The EPA also proposes to
remove sections 4.1.1, 4.1.2, and 4.2.
E. Section 5.0 (Safety)
In this action, the EPA proposes updates to the language of section
5.0, including a recommendation to provide safety data sheets for gas
standards to all personnel using the method.
F. Section 6.0 (Equipment and Supplies)
In this action, the EPA proposes to organize the equipment list in
section 6.0 into analytical instrumentation and sampling system
components. The EPA also proposes to remove the descriptions of the
following equipment, which are not needed to perform revised Method
320:
Calibration/Analyte Spike Assembly.
Mass Flow Meter.
Rotameter.
FTIR Cell Pump.
In this action, the EPA proposes to revise the current descriptions
for the equipment components shown in table 4 of this preamble.
Table 4--Proposed Revisions to Existing Definitions
------------------------------------------------------------------------
Equipment Revision Proposed description
------------------------------------------------------------------------
FTIR Analytical System...... Change ``FTIR An instrument that
Analytical System'' collects and
to ``FTIR digitizes the
Spectrometer,'' spectral
clarify the interference
description, and pattern from an
remove the interferometer and
requirement that mathematically
the system include transforms this
a personal computer signal into
and processing infrared frequency
software. spectra.
Gas Regulators.............. Clarify the A regulator used to
description and add introduce
recommendations individual gas or
regarding materials gas mixtures from
of construction. cylinders.
Regulator should be
constructed of the
appropriate
materials that
minimize analyte
adsorption and
reactivity.
Gas Sample Manifold......... Change ``Gas Sample A manifold capable
Manifold'' to ``Gas of delivering
Distribution nitrogen or
Manifold'' and calibration gases
clarify the through the
description to sampling system or
include directly to the
requirements for FTIR. The
accurately diluting calibration gas
calibration gas, manifold must
monitoring provide accurate
calibration gas dilution of the
pressure, and calibration gas as
precisely necessary, monitor
introducing analyte calibration gas
spikes. pressure, and
introduce analyte
spikes into the
sample stream
(prior to the
particulate filter)
at a precise and
known flowrate.
Particulate Filters......... Clarify the A glass wool plug
description and (optional) inserted
remove the example at the probe tip
cited. (for large
particulate
removal) and a
filter (required)
connected at the
outlet of the
heated probe and
rated for 99%
removal efficiency
of 1 micron ([mu]m)
aerodynamic
particulate.
Polytetrafluoroethane Tubing Incorporate the Polytetrafluoroethan
description into a e (PTFE), 316-
single description stainless steel, or
for ``Tubing''. other inert
material, of
suitable length and
diameter used to
connect cylinder
regulators to the
gas manifold.
Sampling Line/Heating System Change ``Sampling Heated to prevent
Line/Heating sample
System'' to condensation, and
``Sample Line'' and made of stainless
clarify that the steel, PTFE, or
construction other material that
material should minimizes
minimize adsorption adsorption of
of analytes and the analytes. Line
length of line length should be
needed. the minimum
necessary to reach
sampling locations.
Sample Pump................. Update the minimum A leak-free pump
flow rate with bypass valve,
requirements, capable of
clarify the options producing a sample
for pump placement, flow rate equal to
remove the 5 cell volumes per
requirement to sample cycle. The
record the gas cell pump may be
sample pressure for positioned upstream
pumps located or downstream of
downstream of the the FTIR cell. If
FTIR system, and the pump is
remove the example positioned upstream
cited. of the distribution
manifold and FTIR
system, use a
heated head pump
that is constructed
from materials non-
reactive with the
analytes of
interest.
Sample Conditioning......... Clarify the role of An optional part of
the optional sample the sampling system
conditioning in the used to dilute or
sampling system. remove particulate
matter, water
vapor, or other
interfering species
depending upon the
source matrix
composition.
Sampling Probe.............. Clarify the Glass, stainless
description and steel, PTFE, or
remove the example other appropriate
for high- material to
temperature stack transport analytes
samples and the to the IR gas cell.
recommendation to The sampling probe
use a dilution must be capable of
probe for high- sustained heating
moisture sources. to prevent water
condensation and
adsorption of
analytes.
Stainless Steel Tubing...... Incorporate the PTFE, 316-stainless
description into a steel, or other
single description inert material, of
for ``Tubing''. suitable length and
diameter used to
connect cylinder
regulators to the
gas manifold.
------------------------------------------------------------------------
The EPA also proposes to add descriptions for the equipment
components shown in table 5 of this preamble.
[[Page 15106]]
Table 5--Proposed New Equipment Descriptions
------------------------------------------------------------------------
Term Proposed description
------------------------------------------------------------------------
Computer/Data Acquisition A computer with compatible FTIR software
System. for control of the FTIR system,
acquisition of infrared (IR) data, and
analysis of resulting spectra. This
system must have enough data storage
space to archive all necessary infrared
and meta data (see section 11.6 of this
method).
Gas Absorption Cell.......... The container through which the infrared
beam interacts with the sample gas. The
gas absorption cell must have the
ability to monitor the pressure and
temperature of the sample gas.
Sampling System.............. The sampling system consists of the
components listed in sections 6.2.1
through 6.2.9 of this method, validated
as detailed in section 9.4.
------------------------------------------------------------------------
G. Section 7.0 (Reagents and Standards)
In this action, the EPA proposes to rename current section 7.1 from
``Analyte(s) and Tracer Gas'' to ``Analyte(s) and Tracer Standard
Gases'' and to require the use of EPA protocol gases (with expanded
uncertainty <=2%) be used for criteria pollutants. The EPA proposes to
specify that other pollutants (non-criteria) be dual certified and that
target analytes be within 25% of the emission source level or
applicable compliance limit. The EPA also proposes to remove the
suggestion regarding the use of sulfur hexafluoride (SF6)
tracer gas. The EPA is specifically soliciting comment on the approach
of using expanded uncertainty for criteria pollutants as well as not
being prescriptive on the tracer that is used.
In section 7.2 (Calibration Transfer Standard(s)), the EPA proposes
to remove the requirements to select CTS according to section 4.5 of
the FTIR Protocol and to obtain a NIST-traceable standard. The EPA also
proposes to clarify that the CTS must be vendor-certified to 2percent of the cylinder tag value and specifying the list of CTS
standard gases that may be used. The EPA is soliciting comments
regarding CTS gases and providing standardization there to ensure
coverage over a wide wavelength range by using one of the listed gases.
The EPA also proposes to change the name of section 7.3 from
``Reference Spectra'' to ``Chemical Standards,'' and to replace the
reference to EPA reference spectra and procedures in the FTIR Protocol
for preparing reference spectra with requirements to use NIST-certified
or NIST-traceable, vendor-certified chemical standards that meet an
accuracy specification of 5 percent for preparing reference
spectra.
H. Section 8.0 (Sampling and Analysis Procedure)
In this action, the EPA proposes to change the name of section 8.0
from ``Sampling and Analysis Procedure'' to ``Sample Collection,
Preservation, Storage, and Transport,'' to clarify the purpose of the
section in the introductory paragraph, and to remove the list of
testing requirements. The EPA proposes to remove the recommendation to
obtain an initial spectrum for determining a suitable operational path
length and the reference to Figure 1 (sampling train).
In section 8.1 (currently Pretest Preparations and Evaluations),
the EPA proposes to rename the section to ``Pretest Preparations'' and
to remove reference to section 4 of the FTIR Protocol for determining
the optimum sampling system configuration. In section 8.2 (Leak-Check),
the EPA proposes to remove the hyphen from the section title, add a
statement for the user to follow the leak check procedures in the
proposed revised section 11.1 (Leak Check), and remove sections 8.2.1
(Sampling System) and 8.2.2 (Analytical System Leak Check).
In section 8.3 (Detector Linearity), the EPA proposes to replace
the text with a statement for the user to follow the detector linearity
verification procedures in proposed revised section 11.2 (Detector
Linearity). The EPA proposes to remove sections 8.3.1 and 8.3.2, which
provide the options to verify detector linearity by varying the power
incident on the detector by modifying the aperture setting or by using
neutral density filters to attenuate the infrared beam in current,
respectively. The EPA also proposed to incorporate section 8.3.3 into
the proposed revised section 11.2.
For section 8.4 (Data Storage Requirements), the EPA proposes to
replace the data storage requirements with a statement for the user to
follow the data storage requirements in new proposed section 11.8
(Digital Data Storage). The EPA also proposes to remove the requirement
to prepare a backup copy of the field test spectra and the requirement
to record sample conditions, instrument settings, and test records.
In section 8.5 (Background Spectra), the EPA proposes to remove the
requirement to evacuate the gas cell and fill the cell with dry
nitrogen to ambient pressure. The EPA also proposes to remove the
requirement to create a backup copy of the background interferogram and
processed single-beam spectrum and remove sections 8.5.1 (Interference
Spectra) and 8.5.2 for collection of water vapor spectra.
For section 8.6 (Pre-Test Calibrations), the EPA proposes to revise
the requirements for the CTS in section 8.6.1 (Calibration Transfer
Standard) and to replace the QA spike requirements in section 8.6.2 (QA
Spike) with a statement for the user to follow the QA spike
requirements in new proposed section 11.4 (QA Spike).
The EPA proposes to revise section 8.7 (Sampling) by replacing the
introductory paragraph with a statement for the user to follow the
sampling procedures specified in new proposed section 11.5
(Stratification Check). The EPA also proposes to incorporate the
requirements for the signal transmittance from section 8.9 (Sampling QA
and Reporting) into the introductory paragraph and to remove sections
8.7.1 (Batch Sampling) and 8.7.2 (Continuous Sampling).
For section 8.8 (Sampling QA and Reporting), the EPA proposes to
rename the section ``Post-Run CTS'' and add a requirement to record a
post-run CTS. The EPA proposes to incorporate the requirement that
sample integration times be sufficient to achieve the required signal-
to-noise ratio from section 8.8.1 into a proposed revised section
9.1.1.1. The EPA also proposes to remove sections 8.8.1, 8.8.2, 8.8.3,
and 8.8.4 and instead specify the requirements to assign unique file
names, store two copies of interferograms and spectra, and prepare
sample spectrum documentation, respectively.
For section 8.9 (Signal Transmittance), the EPA proposes to
incorporate the requirements for the signal transmittance from section
8.9 into revised section 8.7, and to replace the text in section 8.9
with a proposed requirement to perform post-run QA according to
proposed revised section 9.1.2 (Post-Run QA).
In section 8.10 (Post-Test QA), the EPA proposes to move the post-
test CTS requirements to new proposed section 11.6 (Post-Test CTS). The
EPA also
[[Page 15107]]
proposes to move section 8.11 (Post-Test QA) to proposed revised
section 9.1.2 (Post-Run QA).
I. Section 9.0 (Quality Control)
In this action, the EPA proposes to rename section 9.0 to ``Quality
Assurance and Quality Control'' and to remove the introductory
sentence. The EPA proposes to replace section 9.1 (Spike Materials),
which specifies the accuracy requirements for spike materials, with
revised section 9.1 (Quality Assurance) and to add requirements for
performing pre-test QA. The EPA proposes to move the existing section
8.11 to the proposed revised section 9.1.2 and to remove the reference
to the FTIR Protocol.
For section 9.2 (Spiking Procedure), the EPA proposes to replace
the spiking procedures with a proposed revised section 9.2 (Quality
Control) stating that analyte spike procedure in new proposed section
9.3 (Spike Procedure) and the validation procedure in new proposed
section 9.4 (Method Validation Procedure) evaluate the sampling system
performance and quantify sampling system effects on the measured
concentrations. The EPA also proposes to clarify that the method is
self-validating, provided that the results meet the performance
requirement of the QA spike in new proposed section 11.4, and to remove
the requirement that the results from a previous method validation
support the use of this method in the application.
J. Section 10.0 (Calibration and Standardization)
In this action, the EPA proposes updates to section 10.0 by
replacing section 10.1 (Signal-to-Noise Ratio) with a revised section
10.1 (Analytes) that specifies the procedures for calibrating and
standardizing analytes, replacing section 10.2 (Absorbance Path Length)
with a revised section 10.2 (Interferents), and replacing section 10.3
(Instrument Resolution) with revised section 10.3 (CTS Absorption
Bands). The EPA proposes to replace section 10.4 (Apodization Function)
with a revised section 10.4 (Reference Spectra), which would provide
users with procedures for collecting reference spectra, and to replace
section 10.5 (FTIR Cell Volume) with a revised section 10.5 (Absorption
Cell Path Length Determination), which would specify the revised
procedures for determining the absorption cell path length. The EPA
also proposes to add new section 10.6 (Instrument Resolution) to revise
procedures for determining instrument resolution.
K. Section 11.0 (Data Analysis and Calculations)
In this action, the EPA proposes to change the title of current
section 11.0 to ``Method Procedures.'' The EPA proposes to replace
section 11.1 (Spectral De-Resolution) with a revised section 11.1 that
would provide two options to verify that there are no significant
vacuum-side leaks (i.e., the low-flow test and the vacuum-decay test)
and to replace section 11.2 (Data Analysis) with a revised section 11.2
that would incorporate the requirements in the current introductory
paragraph for section 8.3 and requirements in section 8.3.3. The EPA
also proposes to add several new sections as summarized in table 6 of
this preamble. The EPA requests comment on these leak check approaches.
Table 6--Proposed Additions to Section 11
------------------------------------------------------------------------
Section Description
------------------------------------------------------------------------
11.3 (Gas Cell Pathlength)... Requires verification of the gas cell
pathlength according to the procedures
in revised section 10.6.4.
11.4 (QA Spike).............. Clarifies that the QA spike procedure
assumes that the method has been
validated for each of the target analyte
at the source, rather than for only some
of the target analytes as specified in
current section 8.6.2 and presents the
revised QA spike procedures for use of a
certified standard or use of a non-
certified standard.
11.5 (Sampling).............. Specifies the revised sampling
procedures, including performing a
stratification check.
11.6 (Post-Test CTS)......... Requires comparison of the pre- and post-
test CTS spectra.
11.7 (Record and Report)..... Specifies the revised recording and
reporting requirements.
11.8 (Digital Data Storage).. Incorporates the requirements from
section 8.4.
------------------------------------------------------------------------
L. Section 12.0 (Method Performance Data Analysis and Calculations)
For section 12.0, the EPA proposes to rename the section ``Data
Analysis and Calculations'' and to replace section 12.1 (Spectral
Quality) with a revised section 12.1 that specifies the required
capabilities of the concentration algorithm. The EPA also proposes to
remove section 12.2 (Sampling QA/QC).
M. Section 13.0 (Method Validation Procedure)
In this action, the EPA proposes to rename current section 13.0
from ``Method Validation Procedure'' to ``Method Performance'' and to
remove the introductory paragraph. The EPA also proposes to replace
section 13.1 with a revised section 13.1 (Detection Level), which would
include the proposed requirement that the detection level must be
within 20 percent of the applicable compliance limit, and to replace
section 13.2 (Batch Sampling) with a revised section 13.2 (Background
Deviation), which would incorporate the performance criteria in the
current definition of ``Background Deviation.''
N. Section 14.0 (Pollution Prevention)
In section 14.0, the EPA proposes to remove the sentence describing
the mass of HAP that may be emitted by the extracted sample gas for a
typical 3-hour validation run.
O. Section 15.0 (Waste Management)
The EPA is not proposing any changes to section 15.0 in this
action.
P. Section 16.0 (References)
In section 16.0, the EPA proposes to remove references 1, 2, 4, and
5 through 7, and to add the reference citation and link for the FTIR
Protocol (the current addendum to Method 320).
Q. Section 17.0 (Tables, Diagrams, Flowcharts, and Validation Data)
In this action, the EPA proposes to add new section 17.0, to update
Figure 1 (Extractive FTIR Sampling System), and to remove Table 1
(Example Presentation of Sampling Documentation) and Figure 2
(Fractional Reproducibility).
R. Addendum to Test Method 320
In this action, the EPA proposes to remove the addendum and
associated appendices from Method 320. The proposed revised section
16.0 will include a reference citation and link for the FTIR Protocol.
IV. Statutory and Executive Order Reviews
Additional information about these statutes and Executive orders
can be found at https://www2.epa.gov/laws-regulations/laws-and-executive-orders.
[[Page 15108]]
A. Executive Order 12866: Regulatory Planning and Review and Executive
Order 14094: Modernizing Regulatory Review
This action is not a significant regulatory action as defined in
Executive Order 12866, as amended by Executive Order 14094, and was
therefore not subject to a requirement for Executive Order 12866
review.
B. Paperwork Reduction Act (PRA)
This action does not impose an information collection burden under
the PRA. The revisions being proposed in this action to Method 320 do
not add information collection requirements but make corrections,
clarifications, and updates to existing testing methodology.
C. Regulatory Flexibility Act (RFA)
I certify that this action will not have a significant economic
impact on a substantial number of small entities under the RFA. This
proposed action will not impose any requirements on small entities. The
proposed revisions to Method 320 do not impose any requirements on
regulated entities. Rather, the proposed changes improve the quality of
the results when required by other rules to use Method 320. Revisions
proposed for Method 320 allow contemporary advances in analysis
techniques to be used.
D. Unfunded Mandates Reform Act (UMRA)
This action does not contain any unfunded mandate as described in
UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect
small governments. This action imposes no enforceable duty on any
State, local or Tribal governments or the private sector.
E. Executive Order 13132: Federalism
This action does not have federalism implications. It will not have
substantial direct effects on the States, on the relationship between
the national government and the States, or on the distribution of power
and responsibilities among the various levels of government.
F. Executive Order 13175: Consultation and Coordination With Indian
Tribal Governments
This action does not have Tribal implications as specified in
Executive Order 13175. The revisions being proposed in this action make
corrections, clarifications, and updates to existing testing
methodology. Thus, Executive Order 13175 does not apply to this action.
G. Executive Order 13045: Protection of Children From Environmental
Health Risks and Safety Risks
The EPA interprets Executive Order 13045 as applying only to those
regulatory actions that concern environmental health or safety risks
that the EPA has reason to believe may disproportionately affect
children, per the definition of ``covered regulatory action'' in
section 2-202 of the Executive order.
Therefore, this action is not subject to Executive Order 13045
because it does not concern an environmental health risk or safety
risk. Since this action does not concern human health, EPA's Policy on
Children's Health also does not apply.
H. Executive Order 13211: Actions That Significantly Affect Energy
Supply, Distribution or Use
This action is not subject to Executive Order 13211 because it is
not a significant regulatory action under Executive Order 12866.
I. National Technology Transfer and Advancement Act (NTTAA)
This action involves technical standards. While the EPA identified
ASTM D6348 as being potentially applicable, the Agency does not propose
to use it. Currently, ASTM International (formerly the American Society
for Testing and Materials) is revising ASTM D6348 (Standard Test Method
for Determination of Gaseous Compounds by Extractive Direct Interface
FTIR Spectroscopy), which specifies sampling and analytical procedures
that are similar to EPA Method 320. Because the revised ASTM D6348 may
be an equivalent method, the EPA will reconsider it when the revised
ASTM D6348 becomes available.
J. Executive Order 12898: Federal Actions To Address Environmental
Justice in Minority Populations and Low-Income Populations and
Executive Order 14096: Revitalizing Our Nation's Commitment to
Environmental Justice for All
The EPA believes that this type of action does not concern human
health or environmental conditions and, therefore, cannot be evaluated
with respect to potentially disproportionate and adverse effects on
communities with environmental justice concerns. This action would
correct, update, and clarify Method 320 to improve the quality of the
results when used.
List of Subjects in 40 CFR Part 63
Environmental protection, Air pollution control, Hazardous air
pollutants, Method 320, FTIR, Test methods.
Michael S. Regan,
Administrator.
For the reasons stated in the preamble, the Environmental
Protection Agency proposes to amend title 40, chapter I of the Code of
Federal Regulations as follows:
PART 63--NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS
FOR SOURCE CATEGORIES
0
1. The authority citation for part 63 continues to read as follows:
Authority: 42 U.S.C. 7401 et seq.
0
2. Appendix A to part 63 is amended by revising Test Method 320 to read
as follows:
Appendix A to Part 63--Test Methods
* * * * *
Test Method 320--Measurement of Vapor Phase Organic and Inorganic
Emissions by Extractive Fourier Transform Infrared (FTIR) Spectroscopy
1.0 Scope and Application
This method describes the extractive sampling and quantitative
analysis of gaseous compounds in stationary source effluent using
Fourier transform infrared (FTIR) spectrometry. Analysis procedures,
quality control, and quality assurance requirements are included to
assure that you, the tester, collect data of known and acceptable
quality for each testing program.
1.1 Analytes. This method is designed to measure individual gas
phase hazardous air pollutants (HAPs) for which reference spectra
have been developed. Other gas phase compounds can also be measured
with this method so long as reference spectra obtained according to
section 10.5 of this method are used. Candidate gaseous compounds
must have infrared features (i.e., a non-zero dipole moment) to be
detected using this method.
1.2 Applicability. This method applies to the analysis of vapor
phase compounds that absorb energy in the mid-infrared spectral
region, from about 400 to 4000 cm-1 (25 to 2.5 [mu]m).
The method is used to determine compound-specific concentrations in
a multi-component gas sample extracted from a stack or ducted
source.
1.3 Data Quality Objectives (DQOs). Method 320 contains
performance-based DQOs to provide data of known quality. With this
method, you must evaluate the accuracy and precision of data in each
gas matrix and at actual emissions concentrations that are
encountered during its application. Data quality requirements
include appropriate field evaluation procedures.
2.0 Summary of Method
2.1 A sample is extracted from the source at a constant rate.
Samples are conditioned, if necessary, and transported via heated
lines composed of inert material (to prevent
[[Page 15109]]
condensation of the measured compounds) from the source to a heated
cell in the FTIR, wherein data are generated by directing an
infrared beam through the sample to a detector. Most molecules
absorb infrared radiation, and the absorbance occurs in a
characteristic and reproducible pattern. FTIR data are transformed
into a frequency-based spectra and curve fitting calculations (e.g.,
classical least squares, partial least squares) are used to
determine compound quantities and minimize residuals. Target
compound concentrations are determined using their unique infrared
absorption features and reference calibration spectra. This method
may be used simultaneously for multiple gaseous components.
2.2 Measurement evaluation and validation for a source gas
matrix are described in section 9.2 of this method. Pre-test
preparation and procedures are described in section 8.1 of this
method. These procedures are designed to verify that an appropriate
sampling system has been chosen and performs in a manner that
provides results of known and acceptable quality is also discussed.
Dynamic spiking is used to confirm target compound transport
accuracy in potentially complex matrices.
3.0 Definitions
3.1 Absorbance means the negative logarithm of transmission
represented by the relationship A = -log(I/I0), where I
is the transmitted intensity of light, and I0 is the
incident intensity of light upon a molecule.
3.2 Absorptivity means the amount of infrared radiation absorbed
by each molecule.
3.3 Analyte means a compound that the method is intended to
measure. This method is a multi-component method; therefore, several
analytes may be targeted for a given test.
3.4 Analyte spiking means the process of quantitatively adding
calibration standards to source effluent. Analyte spiking is used to
evaluate the ability of the sample transport and FTIR measurement
systems to quantify the target analyte(s).
3.5 Analytical algorithm means the method used to quantify the
concentration of both target analyte(s) and additional compounds in
a sample matrix that may introduce analytical interferences in each
FTIR spectrum.
3.6 Analytical interference means a spectral feature that
complicates, and may even prevent, the analysis of an analyte.
Analytical interferences can be background or spectral
interferences. Background interferences result from a change in
light throughput relative to the single beam background. This can be
due to factors such as deposits on reflective surfaces and windows,
temperature changes, a change in detector sensitivity, a change in
infrared source output, or instrument electronics failure. Spectral
interferences arise due to the presence of interfering compounds
that have overlapping absorption features with the analytes of
interest.
3.7 Apodization means a mathematical transformation used to
adjust the instrument line shape for measured peaks. There are
various types of apodization functions; the most common are boxcar,
triangular, Happ-Genzel, and Beer-Norton functions.
3.8 Background deviation means a deviation from 100%
transmittance in any region of the 100% line.
3.9 Background spectrum means a spectrum taken in the absence of
absorbing species or sample gas matrix, typically conducted using
nitrogen or zero air.
3.10 Bandwidth means the width of a spectral feature. This width
is commonly listed as the full width at half the maximum of the
spectral feature.
3.11 Beam splitter means a device located in the interferometer
that divides the incoming infrared radiation into two separate beams
that travel two separate paths before recombination.
3.12 Calibration transfer standard (CTS) means a certified gas
calibration standard used to verify instrument stability. For the
purposes of this method, the CTS must be ethylene, methane, or
carbon dioxide. Other compounds may be used only with administrator
approval.
3.13 Classical least squares (CLS) means a method of analyzing
multicomponent spectra by scaling reference absorbance spectra to
unknown measured spectra.
3.14 Double beam spectrum means a transmission or absorbance
spectrum derived by dividing the sample single beam spectrum by the
background spectrum.
Note: The term ``double-beam'' is used elsewhere to denote a
spectrum in which the sample and background interferograms are
collected simultaneously along physically distinct absorption paths.
In this method, the term denotes a spectrum in which the sample and
background interferograms are collected at different times along the
same absorption path.
3.15 Fourier transform means a mathematical transform that
allows the conversion of the detector response as a function of time
to intensity as a function of frequency.
3.16 Fundamental CTS means an NIST-traceable CTS reference
spectrum with known temperature and pressure, that has been obtained
using an absorption cell with an accurately known optical
pathlength.
3.17 Interferogram means a pattern that contains the effects of
the wave interference that are produced from an interferometer.
3.18 Interferometer means a device used to produce interference
spectra, by dividing a beam of radiant energy into two or more
paths. One path strikes a fixed mirror, and the second path strikes
a moving mirror generating an optical path difference that varies
over time between them. The recombined beams produce constructive
and destructive interference as a function of changing pathlength.
The Michelson interferometer, used in FTIR instruments, performs
this function.
3.19 Partial least squares means a method for analyzing
multicomponent spectra by combining features from principal
component and multiple regression analysis. It has been found to be
most useful when predicting a set of dependent variables from a
large set of independent variables.
3.20 Reference spectra means a spectra of a pure sample gas
obtained at a known concentration under controlled conditions of
pressure, temperature, and pathlength.
3.21 Resolution means the minimum separation that two spectral
features must have to distinguish one feature from the another.
3.22 Retardation means the optical path difference between two
beams in an interferometer.
3.23 Run means a series of samples taken successively from the
stack or duct. A test normally consists of a specific number of
runs.
3.24 Single beam spectrum means the Fourier transformed
interferogram representing detector response versus wavenumber.
3.25 Test means the series of runs required by the applicable
regulation.
3.26 Tracer gas means a stable, non-reactive species that is
easily transportable and can be blended in a gas cylinder with a
target analyte to confirm the dilution ratio of a dynamic spike.
3.27 Transmittance means the amount of infrared radiation that
is not absorbed by the sample. Percent transmittance is represented
by the following equation: %T = (I/I0) x 100.
4.0 Interferences
Interferences to precise, accurate measurement using FTIR
include both analytical interferences defined in section 3.6 of this
method, and sampling system interferences. Sampling system
interferences are conditions that prevent analytes from reaching the
instrument due to factors such as sample line temperature, sample
line materials, condensation, and sample transport time.
5.0 Safety
This method does not address all potential safety risks
associated with its use. The hazards of performing this method are
those associated with any stack sampling method. Anyone performing
this method must follow safety and health practices consistent with
stationary source sampling, including applicable legal and site-
specific safety requirements. Many HAPs measured by this method are
suspected toxic or hazardous and may present serious health risks.
Exposure to these compounds from stack gas or from spiking standards
should be avoided. Ensure safety data sheets (SDS) for gas standards
are available to all personnel using this method. When using analyte
standards, ensure that gases are properly vented and that the gas
handling system is leak free.
6.0 Equipment and Supplies
The equipment and supplies described in this section are based
on the schematic of the example sampling system shown in Figure 1.
6.1 Analytical Instrumentation.
6.1.1 Fourier Transform Infrared (FTIR) Spectrometer. An
instrument that collects and digitizes the spectral interference
pattern from an interferometer and mathematically transforms this
signal into infrared frequency spectra.
6.1.2 Computer/Data Acquisition System. A computer with
compatible FTIR software for control of the FTIR system, acquisition
of infrared (IR) data, and analysis of resulting spectra. This
system must have enough data
[[Page 15110]]
storage space to archive all necessary infrared and meta data (see
section 11.6 of this method).
6.1.3 Gas Absorption Cell. The container through which the
infrared beam interacts with the sample gas. The gas absorption cell
must have the ability to monitor the pressure and temperature of the
sample gas.
6.2 Sampling System. The sampling system consists of the
components listed in sections 6.2.1 through 6.2.9 of this method and
validated as detailed in section 9.4.
6.2.1 Sampling Probe. Glass, stainless steel,
polytetrafluoroethane (PTFE), or other appropriate material to
transport analytes to the IR gas cell. The sampling probe must be
capable of sustained heating to prevent water condensation and
adsorption of analytes.
Note: High stack sample temperatures may require special steel
or cooling of the probe. For very high moisture sources, it may be
desirable to use a dilution probe. Special materials or
configurations may be required for probes to traverse ducts or
stacks.
6.2.2 Particulate Filters. A glass wool plug (optional) inserted
at the probe tip (for large particulate removal) and a filter
(required) connected at the outlet of the heated probe and rated for
99% removal efficiency of 1 micron aerodynamic particulate.
6.2.3 Sampling Line. Heated to prevent sample condensation, and
made of stainless steel, PTFE, or other material that minimizes
adsorption of analytes. Line length should be the minimum necessary
to reach sampling locations.
6.2.4 Sample Pump. A leak-free pump with bypass valve, capable
of producing a sample flow rate equal to 5 cell volumes per sample
cycle. The pump may be positioned upstream or downstream of the FTIR
cell. If the pump is positioned upstream of the distribution
manifold and FTIR system, use a heated head pump that is constructed
from materials non-reactive with the analytes of interest.
6.2.5 Gas Distribution Manifold. A manifold capable of
delivering nitrogen or calibration gases through the sampling system
or directly to the FTIR. The calibration gas manifold must provide
accurate dilution of the calibration gas as necessary, monitor
calibration gas pressure, and introduce analyte spikes into the
sample stream (prior to the particulate filter) at a precise and
known flowrate.
6.2.6 Sample Conditioning. An optional part of the sampling
system used to dilute or remove particulate matter, water vapor, or
other interfering species depending upon the source matrix
composition.
6.2.7 Gas Regulator. A regulator used to introduce individual
gas or gas mixtures from cylinders. Regulator should be constructed
of the appropriate materials that minimize analyte adsorption and
reaction with the regulator.
6.2.8 Tubing. PTFE, 316-stainless steel, or other inert
material, of suitable length and diameter used to connect cylinder
regulators to the gas manifold.
7.0 Reagents and Standards
7.1 Analyte(s) and Tracer Standard Gases. Analyte(s) and tracer
gases must come from gas cylinder(s). Criteria pollutants must use
EPA Protocol gases, or equivalent (i.e., compressed gas standards
with an expanded uncertainty of <=2%). All other pollutants must use
``dual certified'' compressed gas standards (i.e., standards
certified by two independent techniques). Target analyte
concentrations should be within 25% of the emission
source levels or the applicable compliance limit unless otherwise
prescribed in the applicable standard. If practical, the analyte
standard cylinder shall also contain the tracer gas at a
concentration that gives a measurable absorbance at a dilution
factor of at least 10:1.
7.2 Calibration Transfer Standard (CTS). The CTS standard must
be NIST-traceable, per methods specified in the EPA Traceability
Protocol for Assay and Certification of Gaseous Calibration
Standards, to 2% of the cylinder tag value. The CTS
standard must be one of the following gases: ethylene, methane, or
carbon dioxide.
7.3 Chemical Standards. Chemical standards used to generate
reference spectra must be NIST certified via gravimetric
measurement, or NIST-traceable and vendor-certified accurate to
within 5%.
8.0 Sample Collection, Preservation, Storage, and Transport
8.1 Pretest Preparations. Determine the optimum sampling system
configuration for measuring the target analytes. Use available
information to make reasonable assumptions about moisture content
and other interferences.
8.1.1 Sampling System.
8.1.1.1 Based on the source gas characteristics (e.g.,
temperature, pressure profiles, moisture content, target and
interference physical characteristics, and particulate
concentration), select the equipment for extracting and transporting
gas samples.
8.1.1.2 Select the techniques and/or equipment for the
measurement of sample pressures and temperatures in the sample cell.
8.1.1.3 Heat sample transport lines to maintain sample
temperature at least 10 [deg]F (5 [deg]C) above the dew point for
all sample constituents. Sample transport lines and system
components must be heated sufficiently through their entire length
to transport target compounds to the IR sample cell.
8.1.2 Select Spectroscopic Setup. Select a spectroscopic
configuration for the application. Approximate the absorption
pathlength, sample pressure, absolute sample temperature, and signal
integration period necessary for the analysis. Specify the nominal
minimum instrumental linewidth (MIL) of the system.
8.1.3 Analytical Program.
8.1.3.1 Prepare an analysis algorithm for acquired spectra. Use
as input, reference spectra of all target analytes and expected
interferents. Include reference spectra of additional interferent
compounds in the program if their presence (even if transient) in
the samples is considered possible. The program output must be in
ppmv (or parts per billion by volume [ppbv]) and must correct for
differences between the reference pathlength (LR),
temperature (TR), and pressure (PR), and the
actual conditions used for collecting the sample spectra.
8.1.3.2 Choose a mathematical technique (e.g., classical least
squares, partial least squares, inverse least squares) for analyzing
spectral data by comparison with reference spectra.
8.1.3.3 Reference spectra incorporated in the program must
either bracket the observed sample matrix concentration or use a
direct injection to verify the calibration curve. Additionally, you
must use a sufficient number (>3) of reference spectra (or reference
spectra plus direct injection checks for low concentration regimes)
in the bracketed range to demonstrate linearity in that
concentration range. Alternatively, if the matrix concentration is
expected to be within three times the detection limit of this
method, you may use calculated reference spectra (i.e., HITRAN or
PNNL) at the lower end of the bracketing range.
8.1.3.4 Analysis regions selected for a target compound(s) must
have an absorbance value of less than 1. You must select specific
wavelengths in each region where the target analyte does not overlap
with an interfering compound and use the selected wavelengths
throughout the entire validation (section 9.4), QA spiking (section
11.4), and testing campaign.
8.2 Leak Check. To conduct the leak check, follow the procedures
specified in section 11.1.
8.3 Detector Linearity. To verify detector linearity, follow the
procedures specified in section 11.2.
8.4 Data Storage Requirements. For these requirements, follow
the procedures specified in section 11.8.
8.5 Background Spectrum. Flow dry nitrogen through the gas cell
and verify that no significant amounts of absorbing species are
present. Collect a background spectrum, using a signal averaging
period equal to or longer than that being used for averaging of
source sample spectra. Assign a unique file name to the background
spectrum.
8.6 Pre-Test Calibrations.
8.6.1 Calibration Transfer Standard. Flow the CTS gas through
the cell and verify that the measured concentration is stable to
within the uncertainty of the gas standard. Record the spectrum.
Additionally, measure the linewidth of appropriate CTS band(s) to
verify instrument resolution. Alternatively, compare CTS spectra to
a reference CTS spectrum, if available, measured at the nominal
resolution.
8.6.2 QA Spike. Conduct a QA spike per the instructions in
section 11.4 of this method.
8.7 Sampling. See section 11.5 of this method. While sampling,
monitor the signal transmittance. If the transmittance (relative to
background) changes by 5% or more in any analytical spectral region,
obtain a new background spectrum.
8.8 Post-Run CTS. After the sampling run, record another CTS
spectrum.
8.9 Perform post-run QA per section 9.1.2 of this method.
9.0 Quality Assurance and Quality Control
9.1 Quality Assurance (QA).
[[Page 15111]]
9.1.1 Pre-Test QA.
9.1.1.1 Prior to testing, verify that the sample integration
time is sufficient to achieve the required signal-to-noise ratio.
9.1.1.2 Assign a unique file name to each spectrum.
9.1.1.3 For reporting and recording requirements, see sections
11.6 and 11.7 of this method.
9.1.2 Post-Test QA.
9.1.2.1 Inspect the sample spectra immediately after the run to
verify the gas matrix composition was close to the expected matrix
composition.
9.1.2.2 Verify that the sampling and instrumental parameters
were appropriate for the actual stack conditions. For example, if
the moisture of the sampled gas was much higher than anticipated, a
shorter pathlength cell or more dilute sample may be needed.
9.1.2.3 Compare the pre- and post-test CTS spectra. The peak
absorbance in the pre- and post-test CTS must be 5% of
the mean value.
9.2 Quality Control (QC). The analyte spike procedure in section
9.3 of this method and the validation procedure in section 9.4 of
this method are used to evaluate the performance of the sampling
system and to quantify sampling system effects, if any, on the
measured concentrations. This method is self-validating provided
that the results meet the performance requirement of the QA spike in
section 11.4 of this method.
9.3 Spike Procedure. Spiking must be done per a standard
addition procedure consisting of measuring the source emissions
concentration (i.e., native source gas concentration), addition of
reference gas, and measurement of the resulting standard addition
(SA) elevated source gas concentration. Spiking must be done
dynamically accounting for the spike dilution of sample gas with the
addition of the reference gas.
9.3.1 Each dynamic spike (DS) or SA replicate consists of a
measurement of the source emissions concentration (native stack
concentration) with and without the addition of the species of
interest. With a single FTIR, you must alternate the measurement of
the native and SA-elevated source gas so that each measurement of
SA-elevated source gas is immediately preceded and followed by a
measurement of native stack gas. Introduce the SA gases in such a
manner that the entire sampling system is challenged. Alternatively,
you may use an independent FTIR and sampling system to measure the
native source concentration throughout each standard addition.
9.3.1.1 Pre and post-test spiking must consist of at least 3
replicates. A replicate is defined as the following measurement
sequence: native gas concentration, SA-elevated gas concentration,
native gas concentration. In addition to the pre-test spike
instance, spiking must also be performed post-test.
9.3.1.2 It is recommended that spiking be performed after each
run to ensure continued compliance with the required spike recovery
criteria. If spiking is not performed after each run and the post-
test spike fails, all data for that test are invalid. However, if
spiking is performed after each run, data bracketed on each end by a
successful spike are valid test data.
9.3.2 Your spike gas flow rate must not contribute more than 10%
of the total volumetric flow rate through the FTIR.
9.3.3 Determine the response time (RT) of the system. First,
inject zero air into the system. For standard addition RT
determination, next measure the native stack concentration of the
species to be spiked. The concentration has stabilized when
variability appears constant for five minutes.
9.3.4 You must determine a dilution factor (DF) for each dynamic
spike. Determine the DF via a tracer, and use the following equation
for a source where the tracer is not native to the source emissions:
[GRAPHIC] [TIFF OMITTED] TP01MR24.037
Where:
Mspiked tracer = the measured diluted tracer gas
concentration in a spiked sample.
Ctracer spiked = the tracer gas concentration injected
with the spike gas.
Note: Use consistent concentration units for each variable in
Equation 1.
In instances where the tracer gas is native to the source
emissions, use the following equation:
[GRAPHIC] [TIFF OMITTED] TP01MR24.038
Where:
Mnative tracer = the measured tracer concentration
present in the native effluent gas.
Cnative tracer = the undiluted tracer gas concentration
in the cylinder.
Note: Use consistent concentration units for each variable in
Equation 2.
9.3.4.1 Standard Addition Response. The standard addition
response (SAR) represents the difference between the measured native
source concentration and the concentration measured upon
introduction of the standard addition (source + SA) via dynamic
spike. Calculate the SAR via the following equation:
[GRAPHIC] [TIFF OMITTED] TP01MR24.039
Where:
MCspiked = the measured reference analyte concentration.
MCnative = the measured concentration of the analyte in
the native effluent.
Note: Use consistent concentration units for each relevant
variable in Equation 3.
9.3.4.2 Effective Spike Addition. The effective spike addition
(ESA) is the expected increase in the measured concentration as a
result of injecting a spike. For the section 11.4 QA spike, the ESA
must be within 50% of the native stack concentration. Calculate the
ESA with the following equation, for use when using a certified
cylinder:
[GRAPHIC] [TIFF OMITTED] TP01MR24.040
Where:
Cspike = the certified reference analyte concentration.
When using a non-certified cylinder, replace the Cspike
term in Equation 4, with MCspiked.
Note: Use consistent concentration units for each relevant
variable in Equation 4.
9.3.4.3 Spike Recovery. The degree to which the SAR and the ESA
agree represents the spike recovery (SR), or the ability to measure
the spiked analyte on top of the amount of that analyte native to
the stack.
[[Page 15112]]
Spike recovery is calculated according to the following equation:
[GRAPHIC] [TIFF OMITTED] TP01MR24.041
9.3.4.4 Spiking Procedure for Highly Variable Sources. In some
instances, a source may be encountered that is too variable for the
procedures listed in sections 9.3 and 11.4 of this method. A highly
variable source, for which this procedure may be used is defined as
a source that varies randomly and by more than 25% from data point
to point, where two consecutive points are less than or equal to a
minute apart. For these types of sources, the approach outlined in
section 9.3.5.4.1 of this method may be used.
9.3.4.4.1 Dual FTIR and Extractive Systems Approach. This field
approach is performed using two independent FTIRs and sample
extraction systems that use tubing of the same length and diameter
and that pull the sample at approximately the same flow rate. One
FTIR characterizes the fluctuations of the target analyte(s) over
time and the second FTIR performs the spike recoveries. Note that
testers can use either a single probe attached to both systems or
separate probes for each system with the probe tips co-located
(within 6 inches) in the sample duct. In either case, it is
mandatory for the spike to occur prior to the PM filter. Perform the
spiking procedure as follows.
Note: This procedure assumes that the dilution factor is
calculated as stated in EPA Method 320 or ASTM D6348-12e from either
a spectroscopic tracer or metered flows.
9.3.4.4.1.1 After positioning the FTIR probes accordingly, begin
pulling sample gas into both FTIR sample analysis cells. Use the
same sampling period and the identical quantification method (i.e.,
same reference spectra for construction and the same regions for
quantification) for each FTIR.
a. Sample the source gas stream for approximately 15 minutes,
collecting at least 8 spectra on each FTIR.
b. Calculate the average concentration of the target analyte(s)
for each FTIR. If the average concentrations determined using the
two FTIRs are not within 10%, either the analysis routines were not
identical, the timing was not consistent, or the sample system or
FTIR cell in one of the FTIRs is reacting with the target
analyte(s). Note: If the average concentrations are not within 10%,
the spike recovery criterion will be more difficult to achieve.
9.3.4.4.1.2 If the average concentrations agree within 10%,
begin flow of the analyte spike into one of the FTIRs. At this
point, the spiked FTIR should have a consistent offset to the
unspiked FTIR. After this offset is consistent, collect a minimum of
8 data points.
9.3.4.4.1.3 Calculate the difference between the average
concentration of the spiked data and the average concentration of
the unspiked data (i.e., the average concentration of the spike)
using equation 6 of this method.
9.3.4.4.1.4 Calculate the recovery (equation 7) of the spike
using the predicted spiked concentration by the dilution factor (as
determined per the reference method used) and the resultant from
Step 3 (equation 6).
[GRAPHIC] [TIFF OMITTED] TP01MR24.042
Where:
SV = Concentration of target analyte spiked into the extracted gas
stream.
Si = Individual concentration results from the spiked FTIR.
n = Number of individual spiked concentration measurements
collected.
Up = Individual concentration results from the unspiked FTIR (native
gas concentration).
p = Number of individual, unspiked concentration measurements
collected.
Note: Use consistent concentration units for each relevant
variable in Equation 6.
[GRAPHIC] [TIFF OMITTED] TP01MR24.043
Where:
SV = Spiked concentration as calculated from Equation 6.
DF = Dilution Factor as determined from tracer in spike gas standard
or from flows.
Spike Cylinder Concentration = Concentration of target analyte(s)
from spike gas standard (e.g., determined from direct injection or
from certified cylinder tag value).
Note: Use consistent concentration units for each relevant
variable in Equation 7.
9.4 Method Validation Procedure.
This validation procedure, which is based on EPA Method 301 (40
CFR part 63, appendix A), must be used to validate this method for
the analytes in a gas matrix. Analytes that have not been validated
for a particular source type may not be measured using Method 320.
Validation at one source may also apply to another type of source,
if it can be shown that the exhaust gas characteristics are similar
at both sources.
9.4.1 Use section 5.3 of Method 301 (40 CFR part 63, appendix
A), the Analyte Spike procedure, with these modifications. The
statistical analysis of the results follows section 6.3 of EPA
Method 301. Section 3 of this method defines terms that are not
defined in Method 301.
9.4.2 The analyte spike is performed dynamically. This means the
spike flow is continuous and constant as spiked samples are
measured.
9.4.3 Introduce the spike gas at the back of the sample probe.
9.4.4 Spiked effluent is carried through all sampling components
downstream of the probe.
9.4.5 A single FTIR system (or more) may be used to collect and
analyze spectra (not quadruplicate integrated sampling trains).
9.4.6 All of the validation measurements are performed
sequentially in a single ``run'' (section 3.23 of this method).
9.4.7 The measurements analyzed statistically are each
independent (section 3.22 of this method).
9.4.8 A validation data set must consist of 12 or more spike
replicates.
10.0 Calibration and Standardization
10.1 Analytes. Select the required detection level
(DLi) and maximum permissible analytical uncertainty
(AUi) for each analyte (1 to i). The required DL must be
equal to or greater than the method DL determined via section 13.1
of this method. Estimate, if possible, the maximum expected
concentration for each analyte (CMAXi). The expected
measurement range is then bounded by DLi and
CMAXi for each analyte.
10.2 Interferents. List all potential interferents applicable to
your source matrix. Collect or obtain spectra of known and suspected
interferences that were acquired using the same optical system that
will be used in the field measurements. You may also use calculated
spectra from sources such as HITRAN as long as the spectral
resolution matches the resolution of source test sample spectra.
These interferents must be included in the analytical algorithm used
to fit FTIR spectra for quantitation.
[[Page 15113]]
10.3 CTS Absorption Bands. Absorption bands used for CTS
quantitation must be at least ten times the root mean square (RMS)
value of the noise equivalent absorbance (NEA) of a wavelength range
nearest to that absorption band. This value, NEARMS\CTS\
can be determined as follows:
10.3.1 Determine the absolute noise equivalent absorption (NEA)
for an analytical region by flowing nitrogen or zero air through the
gas sample cell. The NEA is the peak-to-peak noise in a spectrum
resulting from collection of two successive background spectra.
Therefore, collect two background spectra in succession while the
nitrogen or zero air is continuously flowing through the cell. Note
that the same averaging time must be used for NEA determination as
will be used for actual sample collection.
10.3.2 Calculate NEARMS\CTS\ per the following
equation:
[GRAPHIC] [TIFF OMITTED] TP01MR24.044
Where:
NCTS = the number of absorbance points in the analysis
region for the CTS.
NEAi\CTS\ = the individual absorbance values of the noise
spectrum in the analysis region, i.
10.4 Reference Spectra. Obtain reference spectra for each
analyte, interferant, surrogate, CTS, and tracer.
10.4.1 The tester must report traceability and other pertinent
information for each reference spectrum, for each compound,
including: temperature, pressure, concentration, cylinder source and
specifications, spectral regions of analysis used for quantitation
(with specific wavelength ranges used), and calibration fit
equations and correlations.
10.4.2 If commercially prepared, or other available reference
libraries are used to quantify data, the FTIR spectral resolution
and line position, cell pathlength, temperature and pressure, and
apodization function must be known and reported. Resolution, line
position, and apodization function used for collection of sample
spectra must be the same as those of the reference spectra used for
quantitation.
10.4.3 Reference spectra for each target compound must bracket
the concentration of that compound in the sample stream.
10.4.3.1 In the case where traceable reference spectra provided
by the FTIR manufacturer do not bracket the concentration of a
particular compound, two options are available. A direct injection
of the compound of interest (NIST traceable and certified to 5%) into the FTIR at a concentration lower than that found in
the sample stream and within three times the method detection level,
may be performed to demonstrate the appropriateness of the
calibration line at this level. To perform this check, while
directly injecting the compound of interest into the FTIR, wait for
the concentration of the compound to stabilize. Once stable, verify
that the concentration as determined via the calibration curve is
within 10% of the cylinder value or else do not proceed with
testing.
10.4.3.2 Alternatively, calculated spectra, such as those from
HITRAN or PNNL, may be used at the lower end of the bracketing
range, within three times the method detection level, as well.
10.4.4 Collecting Reference Spectra. In some cases, it may be
necessary for the tester to collect reference spectra prior to
testing. The procedure found in this section is to be used in such a
case.
10.4.4.1 Record a set of CTS spectra.
10.4.4.2 Collect a set of the reference spectra at two or more
concentrations in triplicate over the desired concentration range.
The top of the concentration range must be less than 10 times that
of the bottom of the range.
10.4.4.3 Collect a second set of CTS spectra. The maximum
accepted concentration for each compound shall be higher than the
maximum estimated concentration for both analytes and known
interferents in the effluent gas. For each analyte, the minimum
accepted concentration shall be no greater than ten times the
concentration-pathlength product of that analyte at its required
detection limit.
10.4.4.4 Permanently store the background and interferograms
digitally, and separately. Document details of the mathematical
process (i.e., apodization function) for generating the spectra from
these interferograms. Record sample pressure (Pr), sample
temperature (Tr), reference absorption pathlength
(Lr), and interferogram signal integration period
(tsr).
10.5 Absorption Cell Path Length Determination.
10.5.1 Flow the CTS through the FTIR cell. Once the absorbance
of two consecutive spectra differ by less than or equal to the
uncertainty of the cylinder standard, the CTS spectrum may be
recorded. Note that the CTS gas must be one of the following gases:
ethylene, methane, or carbon dioxide.
10.5.2 Record a set of the absorption spectra of the CTS, and
record the temperature, pressure, and concentration of the CTS.
10.5.3 Record the instrument manufacturer's nominal absorption
pathlength, nominal spectral resolution, and the CTS signal
integration period.
10.5.4 Calculate the reference cell absorption pathlength,
according to the following equation:
[GRAPHIC] [TIFF OMITTED] TP01MR24.045
Where:
Lr = reference cell absorption pathlength.
Lf = fundamental CTS absorption pathlength.
Tr = absolute temperature of reference CTS gas.
Tf = absolute temperature of fundamental CTS gas.
Pr = absolute pressure of reference CTS gas.
Pf = absolute pressure of fundamental CTS gas.
Cr = concentration of the reference CTS gas.
Cf = concentration of the fundamental CTS gas.
{Ar/Af{time} = ratio of the reference CTS
absorbance to the fundamental CTS absorbance, determined by
classical least squares, integrated absorbance area, spectral
subtraction, or peak absorbance techniques.
10.6 Instrument Resolution.
10.6.1 Flow ambient air through the gas cell.
10.6.2 Verify the instrument resolution using a water absorbance
peak near either 1,918 cm-1, 3,050 cm-1, or
3,920 cm-1.
10.6.3 The absorbance of the peak being used for the resolution
determination should be approximately 0.25 absorbance units. Mix
additional humified air or nitrogen with the ambient flow, to
achieve this absorbance.
10.6.4 Record an absorbance spectrum and measure the FWHH of the
chosen water peak. The measured FWHH of the water peak must be
within 5% of the nominal instrument resolution to proceed with
testing.
11.0 Method Procedures
11.1 Leak Check. Verify that there are no significant vacuum-
side leaks using one of the leak tests described in this section.
Perform the vacuum-side leak check after each installation at the
sampling or measurement location. Leak check must be performed prior
to the start of the field test, and after any relocation or
maintenance to the sample transport system. A leak may be detected
either by measuring a small amount of flow when there should be zero
flow, or by measuring the vacuum decay rate. To test for leaks using
loss of vacuum you must know the vacuum-side volume of your sampling
system to within 10% of its true volume.
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11.1.1 Low-Flow Leak Test. Test a sampling system for leaks
using low-flow measurements as follows:
11.1.1.1 Seal the probe end of the system by capping or plugging
the end of the sample probe.
11.1.1.2 Start sampling pumps and operate them until the
pressure stabilizes.
11.1.1.3 Observe/measure the flow through the vacuum-side of the
sampling system. A flow of less than 0.5% of the system's normal in-
use flow rate is acceptable.
Note: For bypass systems, where the sample flow rate through the
vacuum side of the sample system is greater than the FTIR cell flow
rate, the higher flow rate (bypass plus analyzer/FTIR flow rate) is
used as the in-use flow rate when calculating acceptability of the
leak level.
11.1.2 Vacuum-Decay Leak Test. Perform a vacuum-decay leak test
as follows:
11.1.2.1 Seal the probe end of the system as close to the probe
opening as possible by capping or plugging the end of the sample
probe.
11.1.2.2 Operate all vacuum pumps. Draw a vacuum on the sampling
system and let the pressure on the system stabilize.
11.1.2.3 Turn off the sample pumps and seal the system under a
vacuum of 250 mmHg greater than the source static pressure. Record
the absolute pressure and the system absolute temperature every 30
seconds for 5 minutes. The leak rate must be equal to or less than
2.5 mmHg per minute.
11.2 Detector Linearity. Observe the single beam instrument
response in the frequency region below the detector cutoff (usually
<400 cm-1), where the detector response is known to be
zero. Verify that the detector response is ``flat'' and equal to
zero in this region, or at least 100 times less than the peak signal
in the entire spectrum. If the response is not linear, decrease the
aperture or attenuate the IR beam, and repeat the linearity check
until the detector response is linear.
11.3 Gas Cell Pathlength. Verify the gas cell pathlength of your
instrument by following the procedure found in section 10.6.4 of
this method.
11.4 QA Spike. This procedure assumes that the method has been
validated for each of the target analytes at the source. Choose one
of two options and perform the standard addition procedure listed in
ection 9.3 of this method.
Note: For unstable sources, QA spiking may be difficult. An
alternative procedure for such a source is described in section
9.3.5.4.
11.4.1 QA Spike Option 1. Use a certified standard (2% accuracy) for an analyte that has been validated at the
source. One may either spike each analyte of interest or choose an
appropriate surrogate. An appropriate surrogate must have a vapor
pressure that is less than or equal to the analyte of interest and
be less soluble in water. The wavelength at which the surrogate is
to be quantified must be reported and be within 100 wavenumbers of a
wavenumber that will be used to quantify the analyte of interest.
Additionally, the pKa of a surrogate must be within 20% of the pKa
of the analyte of interest. Surrogates are not allowed for the
following analytes: formaldehyde, HCl, HF, NH3, and vinyl
chloride. If the spike recovery, as calculated by Equation 5 of this
method, is within 70-130% then proceed with the testing.
11.4.2 QA Spike Option 2. Use a non-certified cylinder for an
analyte that has been validated at the source. As with Option 1, one
may either spike each analyte of interest or choose an appropriate
surrogate. If the spike recovery, as calculated by equation 5 of
this method, is within 90-110%, then proceed with the testing.
11.5 Sampling. Sampling must be done using a continuous flow of
source gas.
11.5.1 Stratification Check. A stratification check must be
performed, per the steps in this section, to justify sampling at a
single location during testing.
11.5.1.1 Use a probe of appropriate length to measure the
analyte of interest at each of 12 traverse points (MNi,
where i = 1 to 12) located according to section 11.3 of Method 1 in
appendix A-1 to 40 CFR part 60 for a circular stack or nine points
at the centroids of similarly shaped, equal area divisions of the
cross section of a rectangular stack.
11.5.1.2 Calculate the mean measured concentration for all
sampling points (MNavg).
11.5.1.3 Calculate the percent stratification (St) of
each traverse point using the following equation:
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11.5.1.4 The gas stream is considered to be unstratified and you
may perform testing at a single point that most closely matches the
mean if the concentration at each traverse point differs from the
mean concentration for all traverse points by no more than 5.0% of
the mean concentration.
11.5.1.5 If the criteria for single point sampling is not met,
but the concentration at each traverse point differs from the mean
concentration by no more than 10% of the mean, the gas stream is
considered minimally stratified, and you may sample using the ``3-
point short line.''
11.5.1.6 If the concentration at any traverse point differs from
the mean by more than 10%, the gas stream is considered stratified,
and you must sample using the stratification check procedure
specified in section 11.5.1.1 of this method.
11.5.2 Assign a unique filename to each spectrum and separately
to each corresponding interferogram. Spectra and interferograms must
be providable in ``.spc'' format upon request.
11.5.3 Temperature. The temperature of the gas cell must be
measured directly. The temperature measurement device must be
calibrated to within 0.1 [deg]C every 12 months.
11.5.4 Pressure. The gas cell pressure must be measured
empirically. The measurement device must be calibrated to within
1 mmHg every 12 months.
11.5.5 Inspect the sample spectra immediately after the run to
verify that the gas matrix composition was close to the expected
(assumed) gas matrix. Additionally, look at the residual spectra for
each sample spectrum to confirm interferences have been accounted
for.
11.6 Post-Test CTS. At the end of each test, record another CTS
spectrum. Compare the pre- and post-test CTS spectra. The peak
absorbance in pre- and post-test CTS must be 5% of the
mean value.
11.7 Record and Report.
11.7.1 The following must be documented and reported for each
sample spectrum: sampling conditions, sampling time (# of scans per
average and amount of time per scan), instrumental conditions
(pathlength, temperature, pressure, resolution, laser frequency,
instrument make and model), and spectral filename.
11.7.2 Test Report. You must prepare a test report following the
guidance in EPA Guidance Document 043 (Preparation and Review of
Test Reports. December 1998). Additional minimum reporting
requirements are listed here:
11.7.2.1 Instrument and sampling system related items.
a. Instrument make and model.
b. Sampling line length, material, and temperature.
c. Instrument resolution.
d. Cell pathlength, pressure, and temperature.
e. Laser frequency.
f. Cylinder regulator type.
11.7.2.2 Software/Algorithm related items.
a. Gases included in the analysis (interferences + analytes of
interest).
b. Concentration values of reference spectra, as well as
temperature and pressure. information for all interferences and
analytes of interest.
c. Analysis wavelength regions for each compound (interferences
+ analytes of interest).
11.7.2.3 CTS, QA/QC and validation related items.
a. A list of compounds that are being spiked. Note that Method
320 allows for use of qualified surrogates. Qualified surrogates
should be appropriate for the compound actually being measured. It
is preferable that the compound of interest always be spiked if it
is available as a certified standard.
b. Is/are the spike(s) being performed dynamically?
c. Are spikes being introduced at the back of the sample probe
and travelling through the entire sampling system?
d. Are standards being used for QA spiking of appropriate
quality? For example, (2% for Protocol gases where
available and 5% for other certified gases?
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e. Has FTIR been validated for the source under consideration?
11.8 Digital Data Storage. All field test data must be
electronically stored, readily available, and provided to the
regulatory authority upon request. Stored information must include:
sample interferograms, background interferograms, CTS sample
interferograms, processed sample absorbance spectra, and processed
CTS absorbance spectra.
12.0 Data Analysis and Calculations
12.1 Analyte concentrations must be measured using reference
spectra as they are described in section 10.5 of this method. Use
the algorithm developed in section 8.3 of this method to calculate
the concentration of each species in the sample matrix as well as
their respective residuals. Classical least squares, augmented
classical least squares, or partial least squares algorithms must
meet the following criteria:
12.1.1 The algorithm must be capable of correcting for
differences in gas cell pathlength, temperature, and cell pressure
between sample and reference spectra. If the algorithm does not have
this capability, perform this correction using equation 12:
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12.1.2 The algorithm must be capable of reporting spectral
residuals for all compounds being analyzed as a function of its
spectral fit using the techniques in section 11.1 of this method.
13.0 Method Performance
13.1 Detection Level (DL). The DL of this method is defined as
the SAR value where the SAR is greater than three times the residual
value of the corresponding standard addition elevated concentration
(MCspiked). The DL for this method must be less than or
equal to 20% of the applicable compliance limit for the compound
being measured. If this is not the case, Method 320 cannot be used
for such an application.
13.2 Background Deviation. Deviations in absorption greater than
5% in an analytical region are unacceptable, and Method
320 cannot be used under this condition.
14.0 Pollution Prevention
The extracted sample gas is vented outside the enclosure
containing the FTIR system and gas manifold after the analysis. In
typical method applications, the vented sample volume is a small
fraction of the source volumetric flow and its composition is
identical to that emitted from the source. When analyte spiking is
used, spiked pollutants are vented with the extracted sample gas.
Minimize emissions by keeping the spike flow off when not in use.
15.0 Waste Management
Small volumes of laboratory gas standards can be vented through
a laboratory hood. Neat samples must be packed and disposed of
according to applicable regulations. Surplus materials may be
returned to supplier for disposal.
16.0 References
1. Protocol for the Use of Extractive Fourier Transform Infrared
(FTIR) Spectrometry in Analyses of Gaseous Emissions from Stationary
Sources, https://www3.epa.gov/ttn/emc/ftir/FTIRProtocol.pdf.
2. U.S. EPA. Method 301--Field Validation of Pollutant Measurement
Methods from Various Waste Media, 40 CFR part 63, appendix A.
3. EPA Traceability Protocol for Assay and Certification of Gaseous
Calibration Standards, https://www.epa.gov/air-research/epa-traceability-protocol-assay-and-certification-gaseous-calibration-standards.
17.0 Tables, Diagrams, Flowcharts, and Validation Data
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Figure 1. Schematic of FTIR Sampling System
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[FR Doc. 2024-04359 Filed 2-29-24; 8:45 am]
BILLING CODE 6560-50-P