Update of Continuous Instrumental Test Methods, 28082-28104 [06-4196]

Agencies

• ENVIRONMENTAL PROTECTION AGENCY

[Federal Register Volume 71, Number 93 (Monday, May 15, 2006)]
[Rules and Regulations]
[Pages 28082-28104]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 06-4196]



[[Page 28081]]

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Part II





Environmental Protection Agency





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40 CFR Part 60



Update of Continuous Instrumental Test Methods; Final Rule

Federal Register / Vol. 71, No. 93 / Monday, May 15, 2006 / Rules and 
Regulations

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 60

[EPA-OAR-2002-0071; FRL-8165-1]
RIN 2060-AK61


Update of Continuous Instrumental Test Methods

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: On October 10, 2003, the EPA proposed amendments to update 
five instrumental test methods that are used to measure air pollutant 
emissions from stationary sources. These amendments are finalized in 
this document and reflect changes to the proposal to accommodate the 
public comments. This action is made to improve the methods by 
simplifying, harmonizing, and updating their procedures. A large number 
of industries are already subject to provisions that require the use of 
these methods. Some of the affected industries and their North American 
Industrial Classification System (NAICS) are listed under SUPPLEMENTARY 
INFORMATION.

DATES: This final rule is effective on August 14, 2006.

ADDRESSES: EPA has established a docket for this action under Docket ID 
No. OAR-2002-0071. All documents in the docket are listed on the http:/
/www.regulations.gov Web site. Although listed in the index, some 
information is not publicly available, e.g., CBI or other information 
whose disclosure is restricted by statute. Certain other material, such 
as copyrighted material, is not placed on the Internet and will be 
publicly available only in hard copy form. Publicly available docket 
materials are available either electronically through https://
www.regulations.gov or in hard copy at the Air and Radiation Docket, 
Docket ID No. OAR-2003-0071, EPA Docket Center (EPA/DC), EPA West, Room 
B102, 1301 Constitution Ave., NW., Washington, DC. The Public Reading 
Room is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, 
excluding legal holidays. The telephone number for the Public Reading 
Room is (202) 566-1744, and the telephone number for the Air and 
Radiation Docket is (202) 566-1742.

FOR FURTHER INFORMATION CONTACT: Foston Curtis, Measurement Technology 
Group (E143-02), Air Quality Assessment Division, EPA, Research 
Triangle Park, North Carolina 27711; telephone (919) 541-1063; fax 
number (919) 541-0516; electronic mail address: curtis.foston@epa.gov.

SUPPLEMENTARY INFORMATION: 

I. General Information

    A. Affected Entities. Categories and entities potentially regulated 
by the final rule include the following:

------------------------------------------------------------------------
     Examples of regulated entities          SIC codes      NAICS codes
------------------------------------------------------------------------
Fossil Fuel Steam Generators............            3569          332410
Industrial, Commercial, Institutional               3569          332410
 Steam Generating Units.................
Electric Generating.....................            3569          332410
Stationary Gas Turbines.................            3511          333611
Petroleum Refineries....................            2911          324110
Municipal Waste Combustors..............            4953          562213
Kraft Pulp Mills........................            2621          322110
Sulfuric Acid Plants....................            2819          325188
------------------------------------------------------------------------

    This table is not intended to be exhaustive, but rather provides a 
guide for readers regarding entities likely to be affected by this 
action. This table lists examples of the types of entities EPA is now 
aware could potentially be affected by the final rule. Other types of 
entities not listed could also be affected. If you have any questions 
regarding the applicability of this action to a particular entity, 
consult the person listed in the preceding FOR FURTHER INFORMATION 
CONTACT section.
    B. Worldwide Web. In addition to being available in the docket, an 
electronic copy of today's final rule amendments will also be available 
on the Worldwide Web (WWW) through the Technology Transfer Network 
(TTN). Following the Administrator's signature, a copy of the final 
rule will be placed on the TTN's policy and guidance page for newly 
proposed or promulgated rules at https://www.epa.gov/ttn/oarpg. The TTN 
provides information and technology exchange in various areas of air 
pollution control.
    C. Judicial Review. Under section 307(b)(1) of the Clean Air Act 
(CAA), judicial review of the final rule is available only by filing a 
petition for review in the U.S. Court of Appeals for the District of 
Columbia Circuit by July 14, 2006. Under section 307(d)(7)(B) of the 
CAA, only an objection to the final rule that was raised with 
reasonable specificity during the period for public comment can be 
raised during judicial review. Under CAA section 307(b)(2), the 
requirements established by the final rule may not be challenged later 
in civil or criminal proceedings brought by EPA to enforce these 
requirements.
    D. Outline. The information presented in this preamble is organized 
as follows:

I. Background
II. Summary of Major Comments and Revisions Since Proposal
    A. Uncertainty Calculation
    B. Sampling System Bias
    C. Calibration Drift Test
    D. Analyzer Calibration Error Test
    E. Interference Test
    F. Alternative Dynamic Spike Procedure
    G. Sampling Traverse Points
    H. Sampling Dilution Systems
    I. Equipment Heating Specifications
    J. Technology-Specific Analyzers
    K. Calibration Gases
    L. Method 7E Converter Test
III. Summary of Environmental, Energy, and Economic Impacts
    A. Executive Order 12866: Regulatory Planning and Review
    B. Paperwork Reduction Act
    C. Regulatory Flexibility Act
    D. Unfunded Mandates Reform Act
    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 and Safety Risks
    H. Executive Order 13211: Action Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use
    I. NTTAA: National Technology Transfer and Advancement Act
    J. Congressional Review Act

I. Background

    Methods 3A, 6C, 7E, 10, and 20 are instrumental procedures used to 
measure oxygen, carbon dioxide, sulfur dioxide, nitrogen oxides, and 
carbon monoxide emissions in stationary sources. They are prescribed 
for determining compliance with a number of Federal, State, and Local 
regulations. Amendments to update these methods were originally 
proposed on August 27,

[[Page 28083]]

1997 (62 FR 45369) as part of an action to update the test methods in 
40 CFR parts 60, 61, and 63. Eight comment letters were received from 
this proposal with comments pertinent to Methods 3A, 6C, 7E, 10, and 
20. Some commenters thought insufficient notification was given in the 
preamble for the changes being proposed and asked that the instrumental 
method revisions be reproposed as a separate action. This separate 
proposal was published on October 10, 2003 (68 FR 58838) and contained 
additional revisions not included in the first proposal. Sixty one 
comment letters were received from this second proposal. These comments 
along with the comments received from the first proposal were used to 
make the appropriate changes to the proposed revisions.

II. Summary of Major Comments and Revisions Since Proposal

    A. Uncertainty Calculation. Numerous commenters disliked the 
proposed requirement to calculate data uncertainty in the method 
results and thought it inappropriate and confusing. It was noted that 
existing emission limitations were developed using emission data 
derived principally from these same test methods with no consideration 
of uncertainty. Further, the purpose of the Federal test methods is to 
provide a means of demonstrating compliance with the applicable 
requirements on the basis of the test method results. Most commenters 
objected to allowing regulatory agencies (or data end users) the 
discretion of accepting data close to an emission limit if the 
uncertainty determination is questionable, especially since no criteria 
for acceptable uncertainty were identified. The commenters thought that 
measurement uncertainty and data quality objectives present a number of 
very serious issues that are too easy for those without a thorough 
understanding of statistics to misapply. The resulting gray areas would 
incite many frivolous lawsuits by those who would use the perception of 
uncertainty to continuously challenge any decision made related to 
compliance. The commenters noted that the proposed revisions failed to 
provide a definition for uncertainty and the proposed uncertainty 
calculation reflected only two factors (sampling system bias and 
converter efficiency) that contribute to uncertainty, rather than all 
potential measurement factors. They preferred the tester and facility 
have a reasonable assurance that they have met the test requirements 
based on a properly quality assured test, not on an untenable 
uncertainty calculation.
    A number of commenters recommended retaining the bias-corrected 
data calculation currently in Method 6C in place of the proposed data 
uncertainty calculation.
    We agree with the commenters and have dropped the proposed 
requirement to calculate measurement uncertainty. The methods will 
retain a bias-correction for the sample concentration similar to what 
is current in Method 6C.
    B. Sampling System Bias. Several commenters found the proposed 
sampling system bias calculation that is based on the emission standard 
problematic because some units have no emission limit, others have more 
than one limit, and still others have limits in units other than 
concentration (e.g., lbs/hr, lb/mm BTU, or lb/ton feed). Most believed 
analyzer performance and accuracy are best evaluated as a function of 
analyzer span. One commenter wondered why the proposed bias test was 
based on the emission standard, while the other performance tests were 
not.
    In the proposal, the conversion table for sources that have 
standards in units other than concentration and the note in section 
1.3.3 advising the test to be designed around the most stringent 
standard in cases of multiple standards were attempts to alleviate the 
problems the commenters noted. We proposed using the emission limit in 
place of the span in the bias calculation to relieve what was thought 
to be an increased burden of passing the test when lower spans are 
chosen. The intent was to have testers use a consistent value in the 
denominator of the bias equation and emphasize the greatest accuracy in 
the range of the emission standard. This approach appears to have added 
more complication than it was intended to relieve.
    In the final rule, the proposed change to calculate the bias 
relative to the emission standard has been dropped. The bias 
determination as a percentage of the span is retained. However, 
``span'' has been changed to ``calibration span'' which is equivalent 
to the concentration of the high calibration gas as in the proposal. In 
the current methods, the span is any number that doesn't result in the 
emission standard being less than 30 percent of the span. The high 
calibration gas chosen for this span must then be 80-100 percent of the 
span. This allows a concentration interval between the high calibration 
gas and the span that is not quality assured. This interval has been 
eliminated.
    The traditional ``span'' was often mistaken for and used 
interchangeably with ``analyzer range.'' With the ``calibration span,'' 
only the calibrated portion of the analyzer range is of concern, and 
any value that exceeds the calibration span is considered invalid.
    This approach offers several additional advantages. First, it gives 
the tester flexibility to set the calibration range at a convenient 
number that is not excessive. Second, it alleviates concern about the 
quality of data points that are currently allowed between the high 
calibration concentration and the span. Third, if it is properly chosen 
with the majority of measurements in the 20-to-100 percent range, it 
would prevent a tester from choosing an inordinately high calibration 
range which reduces measurement accuracy.
    C. Calibration Drift Test. Commenters generally thought that the 
between-run calibration drift requirement should not be eliminated as 
in the proposal. We have taken this recommendation and retained the 
between-run drift determination.
    D. Analyzer Calibration Error Test. Two commenters thought the 
proposed limit for calibration error of 2 percent of the certified gas 
concentration was unnecessarily restrictive when compared to the 
existing 2 percent of span specification. They noted that EPA gave no 
technical basis for such increased restriction and recommended the 
proposed change be dropped. Others wondered why the same gases were 
required for the analyzer setup and the calibration error test? This 
seemed redundant.
    The proposed requirement that the analyzer calibration error be 
within 2 percent of the tag value has been changed to 2 percent of the 
calibration span. The proposed requirement to calibrate the instrument 
with the same gases used in the calibration error test has been 
dropped.
    E. Interference Test. Commenters in general objected to EPA's 
proposed requirement to conduct the interference test on an annual 
basis. They noted that little evidence was provided to show that annual 
interference testing was necessary. They believed the test should only 
be repeated after major instrument modifications. Annual interference 
testing was thought to put a major burden on the testing companies.
    The commenters raised valid concerns. The proposed requirement to 
conduct the interference test on an annual basis has been dropped. The 
interference test will remain a one-time test except for major 
instrument modifications, as is the current requirement. The current 
interference test in Method 6C, where the analyzer is compared to 
modified Method 6

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samples in the field, is now listed as the alternative interference 
test procedure since this approach was considered archaic by some 
commenters. An interference test where the analyzer is challenged by 
potential interferent gases is now the primary procedure.
    F. Alternative Dynamic Spike Procedure. Commenters thought the 
dynamic spiking procedure was confusing and lacked sufficient detail to 
perform. Some commenters thought adding the procedure was a good idea; 
others strenuously objected to even allowing it as an option.
    We have retained the allowance to use dynamic spiking as an 
alternative to the interference and bias tests, except for part 75 
applications, where Administrative approval is required to use the 
procedure. We purposely made the procedure general and performance-
based instead of making it prescriptive because different procedures 
may be followed to perform it successfully. We believe that dynamic 
spiking is a valuable tool for evaluating a method and should be 
retained as an alternative for testers able to perform it. Clarity has 
been added to the procedure details where possible to remove confusion.
    G. Sampling Traverse Points. Comments were mixed on the proposed 
requirement to use Method 1 unless a stratification test showed fewer 
sampling point are justified. The majority did not think a Method 1 
determination was justified for gaseous sampling in all cases and that 
this made the methods burdensome and significantly more costly to use. 
Others proposed reducing the number of points to three, as are allowed 
in relative accuracy testing of continuous emission monitoring systems. 
Two commenters recommended dropping the proposed requirement to correct 
the pollutant concentration for diluent in the stratification test.
    In the final rule, the tester may either sample at twelve Method 1 
points or a stratification test (3-point or 12-point) may be performed. 
If the stratification test is done and results in a concentration 
deviation of any point from the mean concentration by more than 10 
percent, then a minimum of twelve traverse points located according to 
Method 1 must be sampled. If the concentrations of all stratification 
test points are less than 10 percent from the mean, the testing may 
resume using 3 traverse points. If the concentrations at all 
stratification test points are less than 5 percent from the mean, then 
single-point testing may be performed. Note that these traverse point 
layout rules are not intended to apply to relative accuracy test audits 
(RATA) of continuous emission monitoring systems (CEMS) where 
applicable CEMS quality assurance requirements specify specific 
traverse point selection requirements for RATA.
    H. Sampling Dilution Systems. Commenters recommended that EPA 
specifically state that dilution-based sampling technology is an 
acceptable technique. These systems have been approved by the Emission 
Measurement Center (EMC) as alternative method ALT-007 (Use of Dilution 
Probes with Instrumental Methods). Guidance Document 18 from EMC also 
indicates that dilution sampling systems are acceptable for use with 
Methods 6C, 7E, 20, and 10, and the special requirements of dilution-
based sampling are addressed. This information, or the discussions 
found in Chapter 21 of the Part 75 Emissions Monitoring Policy Manual 
were recommended for addition to the methods.
    The instrumental methods have been modified to clearly note that 
dilution systems are acceptable. We have included discussions of 
calibration gas needs relative to the sample gas molecular weight, 
calibration drift test variations, and other instructions pertinent to 
dilutions systems that were a part of EMC Guidance Document GD-18.
    I. Equipment Heating Specifications. Several commenters criticized 
the numerous references to equipment heating that were thought to 
preclude the use of other techniques of preventing sample loss. We were 
urged to require that the sample be maintained at a temperature above 
the dew point of the sample gas rather than specifying minimum 
equipment temperatures to provide a technology-neutral approach.
    The language has been changed to allow the tester to choose which 
procedure or technology to use for preventing condensation. The final 
rule requires the sample gas be maintained above the dew point of the 
stack gas (including all gas components, e.g. acid gas constituents) so 
that no loss of sample results. This may be done by heating, diluting, 
drying, desiccating, a combination thereof, or by other means.
    J. Technology-Specific Analyzers. Various references to specific 
technologies throughout the methods were noted. Most commenters wanted 
us to remove these references. One commenter implicated electrochemical 
cells for providing completely unreliable results when not operated in 
diffusion limiting conditions even though such analyzers could meet the 
performance criteria of the proposal while operating outside of 
diffusion-limiting conditions. The commenter recommended this 
technology be subject to special procedures such as those included in 
ASTM D6522-00.
    We have removed the references to specific technologies in the 
methods to make them flexible and performance-based, not technology-
based. It may be difficult to set performance requirements that 
appropriately evaluate all analytical techniques 100 percent of the 
time. However, we believe the interference, calibration error, and bias 
tests provide adequate assessments of performance for the majority of 
the time. The electrochemical analyzer has been shown capable of 
producing reliable results in an Environmental Technology Verification 
study, and we do not believe special restrictions should be placed on 
this technology.
    K. Calibration Gases. Commenters asked that we list all of the 
allowable calibration gas blends in the methods. They wanted the 
wording changed to allow the flexibility of blending standards with 
other gases that can be shown not to interfere. One commenter thought 
the proposed mid-level calibration gas range of 20 to 70 percent of the 
span-level gas was an improvement over the existing 40 to 60 percent 
range. Another commenter thought this would allow for poor selection of 
mid-level gases. Other commenters wondered if it was acceptable to 
prepare calibration gases from a single high-concentration EPA 
Traceability Protocol gas using Method 205.
    Blended calibration gases are allowed in the final rule provided 
they are made from Traceability Protocol gases and any additional gas 
components are shown not to interfere with the analysis. After 
considering the comments, the EPA has decided to retain the current 40- 
to 60-percent of span requirement for the mid-level gas. We believe 
this ensures a better evaluation of the analyzer's linear response, as 
noted by one of the commenters. In the final rule, Method 205 is 
allowed to prepare calibration gases from high-concentration gases of 
EPA Traceability Protocol quality, except for part 75 applications, 
which require administrative approval to use this technique.
    L. Method 7E Converter Test. Several commenters noted that the 
nitrogen dioxide (NO2) calibration gas used in the converter 
efficiency test is not available as an EPA Traceability Protocol 
Standard as required. This prevents one from performing the test. 
Because NO2 has unusual storage problems, it is difficult to 
maintain the gas at its certified concentration. A search of vendors 
has shown that gas of

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traceability protocol quality is available commercially, but in limited 
concentrations and from limited sources. We also concur with the long-
term stability problems noted with NO2 cylinder gas. Because 
of these concerns, we have retained the original procedures cited in 
Method 20 for determining converter efficiency and have listed the 
proposed procedure for direct evaluation with NO2 as an 
allowable alternative. Numerous commenters pointed out the error in the 
converter efficiency correction in the uncertainty calculation. This 
error has been corrected through a new equation.
    Commenters generally thought that requiring the converter 
efficiency gas be in the concentration range of the source emissions 
was too restrictive and would require numerous gas cylinders be 
transported into the field. We understand the difficulty in preparing 
test gases to match anticipated emission levels. Therefore, we have 
dropped the proposed requirement to match the stack NO2 
concentration within 50 percent and instead require gas in the 40 to 60 
ppm range for all cases.

IV. Summary of Environmental, Energy, and Economic Impacts

A. Executive Order 12866: Regulatory Planning and Reviews

    Under Executive Order 12866 (58 FR 51735 October 4, 1993), the EPA 
must determine whether this regulatory action is ``significant'' and 
therefore subject to review by the Office of Management and Budget 
(OMB) and the requirements of the Executive Order. The Order defines 
``significant regulatory action'' as one that is likely to result in a 
rule that may: (1) Have an annual effect on the economy of $100 million 
or more or adversely affects in a material way the economy, a sector of 
the economy, productivity, competition, jobs, the environment, public 
health or safety, or State, Local, or Tribal governments or 
communities; (2) create a serious inconsistency or otherwise interferes 
with an action taken or planned by another agency; (3) materially alter 
the budgetary impact of entitlements, grants, user fees, or loan 
programs, or the rights and obligations of recipients thereof; or (4) 
raise novel legal or policy issues arising out of legal mandates, the 
President's priorities, or the principles set forth in the Executive 
Order.
    We have determined that this rule is not a ``significant regulatory 
action'' under the terms of Executive Order 12866 and is therefore not 
subject to OMB review. We have determined that this regulation would 
result in none of the economic effects set forth in Section 1 of the 
Order because it does not impose emission measurement requirements 
beyond those specified in the current regulations, nor does it change 
any emission standard.

B. Paperwork Reduction Act

    This action does not impose an information collection burden under 
the provisions of the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. 
These criteria do not add information collection requirements beyond 
those currently required under the applicable regulation. The 
amendments being made to the test methods do not add information 
collection requirements but make needed updates to existing testing 
methodology.
    Burden means the total time, effort, or financial resources 
expended by persons to generate, maintain, retain, or disclose or 
provide information to or for a Federal agency. This includes the time 
needed to review instructions; develop, acquire, install, and utilize 
technology and systems for the purposes of collecting, validating, and 
verifying information, processing and maintaining information, and 
disclosing and providing information; adjust the existing ways to 
comply with any previously applicable instructions and requirements; 
train personnel to be able to respond to a collection of information; 
search data sources; complete and review the collection of information; 
and transmit or otherwise disclose the information.
    An agency may not conduct or sponsor, and a person is not required 
to respond to a collection of information unless it displays a 
currently valid OMB control number. The OMB control numbers for EPA's 
regulations in 40 CFR are listed in 40 CFR part 9.

C. Regulatory Flexibility Act

    EPA has determined that it is not necessary to prepare a regulatory 
flexibility analysis in connection with this final rule.
    For purposes of assessing the impacts of today's rule on small 
entities, small entity is defined as: (1) A small business as defined 
by the Small Business Administrations' regulations at 13 CFR 121.201; 
(2) a small governmental jurisdiction that is a government of a city, 
county, town, school district or special district with a population of 
less than 50,000; and (3) a small organization that is any not-for-
profit enterprise which is independently owned and operated and is not 
dominant in its field. Entities potentially affected by this action 
include those listed in Table 1 of SUPPLEMENTARY INFORMATION.
    After considering the economic impacts of today's final rule on 
small entities, I have concluded that this action will not have a 
significant economic impact on a substantial number of small entities. 
This rule reflects changes to the proposal to accommodate the public 
comments and is made to improve the test methods by simplifying, 
harmonizing, and updating their procedures. A large number of the 
regulated industries are already subject to the provisions that require 
the use of these methods and this rule does not impose any new emission 
measurement requirements beyond those specified in the current 
regulations, nor does it change any emission standard but makes needed 
updates to existing testing methodology. This rule would also add some 
flexibility by giving testers more choice in selecting their test 
equipment which could translate into reduced costs for the regulated 
industries.

D. Unfunded Mandates Reform Act

    Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), Public 
Law 104-4, establishes requirements for Federal agencies to assess the 
effects of their regulatory actions on State, Local, and Tribal 
governments and the private sector. Under section 202 of the UMRA, EPA 
generally must prepare a written statement, including a cost-benefit 
analysis, for proposed and final rules with ``Federal mandates'' that 
may result in expenditures to State, Local, and Tribal governments, in 
the aggregate, or to the private sector, of $100 million or more in any 
one year. Before promulgating an EPA rule for which a written statement 
is needed, section 205 of the UMRA generally requires EPA to identify 
and consider a reasonable number of regulatory alternatives and adopt 
the least costly, most cost-effective or least burdensome alternative 
that achieves the objectives of the rule. The provisions of section 205 
do not apply when they are inconsistent with applicable law. Moreover, 
section 205 allows EPA to adopt an alternative other than the least 
costly, most cost-effective or least burdensome alternative if the 
Administrator publishes with the final rule an explanation why that 
alternative was not adopted. Before EPA establishes any regulatory 
requirements that may significantly or uniquely affect small 
governments, including tribal governments, it must have developed under 
section 203 of the UMRA a small government agency plan. The plan must 
provide for notifying potentially

[[Page 28086]]

affected small governments, enabling officials of affected small 
governments to have meaningful and timely input in the development of 
EPA regulatory proposals with significant Federal intergovernmental 
mandates, and informing, educating, and advising small governments on 
compliance with the regulatory requirements.
    Today's rule contains no Federal mandates (under the regulatory 
provisions of Title II of the UMRA) for State, Local, or Tribal 
governments or the private sector. The rule imposes no enforceable duty 
on any State, Local, or Tribal governments or the private sector. In 
any event, EPA has determined that this rule does not contain a Federal 
mandate that may result in expenditures of $100 million or more for 
State, Local, and Tribal governments, in the aggregate, or the private 
sector in any one year. Thus, today's rule is not subject to the 
requirements of sections 202 and 205 of the UMRA.

E. Executive Order 13132: Federalism

    Executive Order 13132, entitled ``Federalism'' (64 FR 43255, August 
10, 1999), requires EPA to develop an accountable process to ensure 
``meaningful and timely input by State and Local officials in the 
development of regulatory policies that have federalism implications.'' 
``Policies that have federalism implications'' are defined in the 
Executive Order to include regulations that 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.''
    This rule 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, as 
specified in Executive Order 13132. Thus, the requirements of section 6 
of the Executive Order do not apply to this rule.

F. Executive Order 13175: Consultation and Coordination With Tribal 
Governments

    Executive Order 13175, entitled ``Consultation and Coordination 
with Indian Tribal Governments'' (65 FR 67249, November 6, 2000), 
requires EPA to develop an accountable process to ensure ``meaningful 
and timely input by tribal officials in the development of regulatory 
policies that have tribal implications.'' ``Policies that have tribal 
implications'' is defined in the Executive Order to include regulations 
that have ``substantial direct effects on one or more Indian tribes, on 
the relationship between the Federal government and the Indian tribes, 
or on the distribution of power and responsibilities between the 
Federal government and Indian tribes.''
    This final rule does not have tribal implications. It will not have 
substantial direct effects on tribal governments, on the relationship 
between the Federal government and Indian tribes, or on the 
distribution of power and responsibilities between the Federal 
government and Indian tribes, as specified in Executive Order 13175. In 
this final rule, we are simply updating existing pollutant test 
methods. Thus, Executive Order 13175 does not apply to this rule.

G. Executive Order 13045: Protection of Children From Environmental 
Health Risks and Safety Risks

    Executive Order 13045 applies to any rule that EPA determines (1) 
is ``economically significant'' as defined under Executive Order 12866, 
and (2) the environmental health or safety risk addressed by the rule 
has a disproportionate effect on children. If the regulatory action 
meets both criteria, the Agency must evaluate the environmental health 
or safety effects of the planned rule on children and explain why the 
planned regulation is preferable to other potentially effective and 
reasonably feasible alternatives considered by the Agency.
    The EPA interprets Executive Order 13045 as applying only to 
regulatory actions that are based on health or safety risks, such that 
the analysis required under section 5-501 of the Executive Order has 
the potential to influence the regulation. This final rule is not 
subject to Executive Order 13045 because it is not based on health or 
safety risks.

H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use

    This action is not subject to Executive Order 13211, ``Actions 
Concerning Regulations that Significantly Affect Energy Supply, 
Distribution, or Use'' (66 FR 28355, May 22, 2001) because it is not a 
significant regulatory action under Executive Order 12866.

I. NTTAA: National Technology Transfer and Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (NTTAA), Public Law 104-113 (15 U.S.C. 272), directs us to 
use voluntary consensus standards (VCS) in our regulatory activities 
unless to do so would be inconsistent with applicable law or otherwise 
impractical. Voluntary consensus standards are technical standards 
(e.g., materials specifications, test methods, sampling procedures, 
business practices, etc.) that are developed or adopted by VCS bodies. 
The NTTAA requires us to provide Congress, through OMB, explanations 
when we decide not to use available and applicable VCS. We are 
requiring new test methods in this rulemaking. Therefore, NTTAA does 
not apply.

J. Congressional Review Act

    The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the 
Small Business Regulatory Enforcement Fairness Act of 1996, generally 
provides that before a rule may take effect, the agency promulgating 
the rule must submit a rule report, which includes a copy of the rule, 
to each House of the Congress and to the Comptroller General of the 
United States. The EPA will submit a report containing the final rule 
amendments and other required information to the U.S. Senate, the U.S. 
House of Representatives, and the Comptroller General of the United 
States prior to publication of the final rule amendments in the Federal 
Register. A major rule cannot take effect until 60 days after its 
publication in the Federal Register. This action is not a ``major 
rule'' as defined by 5 U.S.C. 804(2). The final rule amendments will be 
effective on July 14, 2006.

List of Subjects in 40 CFR Part 60

    Environmental protection, Air pollution control, New sources, Test 
methods and procedures, Performance specifications, and Continuous 
emission monitors.

    Dated: April 28, 2006.
Stephen L. Johnson,
Administrator.

0
For the reasons stated in the preamble, title 40, chapter I, part 60 of 
the Code of Federal Regulations is amended as follows:

PART 60--[AMENDED]

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1. The authority citation for part 60 continues to read as follows:

    Authority: 42 U.S.C. 7401 et seq.


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2. Appendix A-2 is amended by revising Method 3A to read as follows:

Appendix A-2 to Part 60--Test Methods 2G Through 3C

* * * * *

[[Page 28087]]

Method 3A--Determination of Oxygen and Carbon Dioxide Concentrations in 
Emissions From Stationary Sources (Instrumental Analyzer Procedure)

1.0 Scope and Application

What is Method 3A?

    Method 3A is a procedure for measuring oxygen (O2) 
and carbon dioxide (CO2) in stationary source emissions 
using a continuous instrumental analyzer. Quality assurance and 
quality control requirements are included to assure that you, the 
tester, collect data of known quality. You must document your 
adherence to these specific requirements for equipment, supplies, 
sample collection and analysis, calculations, and data analysis.
    This method does not completely describe all equipment, 
supplies, and sampling and analytical procedures you will need but 
refers to other methods for some of the details. Therefore, to 
obtain reliable results, you should also have a thorough knowledge 
of these additional test methods which are found in appendix A to 
this part:
    (a) Method 1--Sample and Velocity Traverses for Stationary 
Sources.
    (b) Method 3--Gas Analysis for the Determination of Molecular 
Weight.
    (c) Method 4--Determination of Moisture Content in Stack Gases.
    (d) Method 7E--Determination of Nitrogen Oxides Emissions from 
Stationary Sources (Instrumental Analyzer Procedure).
    1.1 Analytes. What does this method determine? This method 
measures the concentration of oxygen and carbon dioxide.

------------------------------------------------------------------------
            Analyte                  CAS No.           Sensitivity
------------------------------------------------------------------------
Oxygen (O2)....................       7782-44-7  Typically <2% of
                                                  Calibration Span.
Carbon dioxide (CO2)...........        124-38-9  Typically <2% of
                                                  Calibration Span.
------------------------------------------------------------------------

    1.2 Applicability. When is this method required? The use of 
Method 3A may be required by specific New Source Performance 
Standards, Clean Air Marketing rules, State Implementation Plans and 
permits, where measurements of O2 and CO2 
concentrations in stationary source emissions must be made, either 
to determine compliance with an applicable emission standard or to 
conduct performance testing of a continuous emission monitoring 
system (CEMS). Other regulations may also require the use of Method 
3A.
    1.3 Data Quality Objectives. How good must my collected data be? 
Refer to Section 1.3 of Method 7E.

2.0 Summary of Method

    In this method, you continuously or intermittently sample the 
effluent gas and convey the sample to an analyzer that measures the 
concentration of O2 or CO2. You must meet the 
performance requirements of this method to validate your data.

3.0 Definitions

    Refer to Section 3.0 of Method 7E for the applicable 
definitions.

4.0 Interferences [Reserved]

5.0 Safety

    Refer to Section 5.0 of Method 7E.

6.0 Equipment and Supplies

    Figure 7E-1 in Method 7E is a schematic diagram of an acceptable 
measurement system.
    6.1 What do I need for the measurement system? The components of 
the measurement system are described (as applicable) in Sections 6.1 
and 6.2 of Method 7E, except that the analyzer described in Section 
6.2 of this method must be used instead of the analyzer described in 
Method 7E. You must follow the noted specifications in Section 6.1 
of Method 7E except that the requirements to use stainless steel, 
Teflon, or non-reactive glass filters do not apply. Also, a heated 
sample line is not required to transport dry gases or for systems 
that measure the O2 or CO2 concentration on a 
dry basis, provided that the system is not also being used to 
concurrently measure SO2 and/or NOX.
    6.2 What analyzer must I use? You must use an analyzer that 
continuously measures O2 or CO2 in the gas 
stream and meets the specifications in Section 13.0.

7.0 Reagents and Standards

    7.1 Calibration Gas. What calibration gases do I need? Refer to 
Section 7.1 of Method 7E for the calibration gas requirements. 
Example calibration gas mixtures are listed below.
    (a) CO2 in nitrogen (N2).
    (b) CO2 in air.
    (c) CO2/SO2 gas mixture in N2.
    (d) O2/SO2 gas mixture in N2.
    (e) O2/CO2/SO2 gas mixture in 
N2.
    (f) CO2/NOX gas mixture in N2.
    (g) CO2/SO2/NOX gas mixture in 
N2.
    The tests for analyzer calibration error and system bias require 
high-, mid-, and low-level gases.
    7.2 Interference Check. What reagents do I need for the 
interference check? Potential interferences may vary among available 
analyzers. Table 7E-3 of Method 7E lists a number of gases that 
should be considered in conducting the interference test.

8.0 Sample Collection, Preservation, Storage, and Transport

    8.1 Sampling Site and Sampling Points. You must follow the 
procedures of Section 8.1 of Method 7E to determine the appropriate 
sampling points, unless you are using Method 3A only to determine 
the stack gas molecular weight and for no other purpose. In that 
case, you may use single-point integrated sampling as described in 
Section 8.2 of Method 3. If the stratification test provisions in 
Section 8.1.2 of Method 7E are used to reduce the number of required 
sampling points, the alternative acceptance criterion for 3-point 
sampling will be  0.5 percent CO2 or 
O2, and the alternative acceptance criterion for single-
point sampling will be  0.3 percent CO2 or 
O2.
    8.2 Initial Measurement System Performance Tests. You must 
follow the procedures in Section 8.2 of Method 7E. If a dilution-
type measurement system is used, the special considerations in 
Section 8.3 of Method 7E apply.
    8.3 Interference Check. The O2 or CO2 
analyzer must be documented to show that interference effects to not 
exceed 2.5 percent of the calibration span. The interference test in 
Section 8.2.7 of Method 7E is a procedure that may be used to show 
this. The effects of all potential interferences at the 
concentrations encountered during testing must be addressed and 
documented. This testing and documentation may be done by the 
instrument manufacturer.
    8.4 Sample Collection. You must follow the procedures in Section 
8.4 of Method 7E.
    8.5 Post-Run System Bias Check and Drift Assessment. You must 
follow the procedures in Section 8.5 of Method 7E.

9.0 Quality Control

    Follow quality control procedures in Section 9.0 of Method 7E.

10.0 Calibration and Standardization

    Follow the procedures for calibration and standardization in 
Section 10.0 of Method 7E.

11.0 Analytical Procedures

    Because sample collection and analysis are performed together 
(see Section 8), additional discussion of the analytical procedure 
is not necessary.

12.0 Calculations and Data Analysis

    You must follow the applicable procedures for calculations and 
data analysis in Section 12.0 of Method 7E, substituting percent 
O2 and percent CO2 for ppmv of NOX 
as appropriate.

13.0 Method Performance

    The specifications for the applicable performance checks are the 
same as in Section 13.0 of Method 7E except for the alternative 
specifications for system bias, drift, and calibration error. In 
these alternative specifications, replace the term ``0.5 ppmv'' with 
the term ``0.5 percent O2'' or ``0.5 percent 
CO2'' (as applicable).

14.0 Pollution Prevention [Reserved]

15.0 Waste Management [Reserved]

16.0 Alternative Procedures [Reserved]

17.0 References

    1. ``EPA Traceability Protocol for Assay and Certification of 
Gaseous Calibration Standards'' September 1997 as amended, EPA-600/
R-97/121.

18.0 Tables, Diagrams, Flowcharts, and Validation Data

    Refer to Section 18.0 of Method 7E.
* * * * *

[[Page 28088]]


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3. Appendix A-4 is amended by revising Methods 6C, 7E, and 10 to read 
as follows:

Appendix A-4 to Part 60--Test Methods 6 Through 10B

* * * * *

Method 6C--Determination of Sulfur Dioxide Emissions From Stationary 
Sources (Instrumental Analyzer Procedure)

1.0 Scope and Application

What is Method 6C?

    Method 6C is a procedure for measuring sulfur dioxide 
(SO2) in stationary source emissions using a continuous 
instrumental analyzer. Quality assurance and quality control 
requirements are included to assure that you, the tester, collect 
data of known quality. You must document your adherence to these 
specific requirements for equipment, supplies, sample collection and 
analysis, calculations, and data analysis.
    This method does not completely describe all equipment, 
supplies, and sampling and analytical procedures you will need but 
refers to other methods for some of the details. Therefore, to 
obtain reliable results, you should also have a thorough knowledge 
of these additional test methods which are found in appendix A to 
this part:
    (a) Method 1--Sample and Velocity Traverses for Stationary 
Sources.
    (b) Method 4--Determination of Moisture Content in Stack Gases.
    (c) Method 6--Determination of Sulfur Dioxide Emissions from 
Stationary Sources.
    (d) Method 7E--Determination of Nitrogen Oxides Emissions from 
Stationary Sources (Instrumental Analyzer Procedure).
    1.1 Analytes. What does this method determine? This method 
measures the concentration of sulfur dioxide.

------------------------------------------------------------------------
            Analyte                  CAS No.           Sensitivity
------------------------------------------------------------------------
SO2............................       7446-09-5  Typically <2% of
                                                  Calibration Span.
------------------------------------------------------------------------

    1.2 Applicability. When is this method required? The use of 
Method 6C may be required by specific New Source Performance 
Standards, Clean Air Marketing rules, State Implementation Plans, 
and permits where SO2 concentrations in stationary source 
emissions must be measured, either to determine compliance with an 
applicable emission standard or to conduct performance testing of a 
continuous emission monitoring system (CEMS). Other regulations may 
also require the use of Method 6C.
    1.3 Data Quality Objectives. How good must my collected data be? 
Refer to Section 1.3 of Method 7E.

2.0 Summary of Method

    In this method, you continuously sample the effluent gas and 
convey the sample to an analyzer that measures the concentration of 
SO2. You must meet the performance requirements of this 
method to validate your data.

3.0 Definitions

    Refer to Section 3.0 of Method 7E for the applicable 
definitions.

4.0 Interferences

    Refer to Section 4.1 of Method 6.

5.0 Safety

    Refer to Section 5.0 of Method 7E.

6.0 Equipment and Supplies

    Figure 7E-1 of Method 7E is a schematic diagram of an acceptable 
measurement system.
    6.1 What do I need for the measurement system? The essential 
components of the measurement system are the same as those in 
Sections 6.1 and 6.2 of Method 7E, except that the SO2 
analyzer described in Section 6.2 of this method must be used 
instead of the analyzer described in Section 6.2 of Method 7E. You 
must follow the noted specifications in Section 6.1 of Method 7E.
    6.2 What analyzer must I use? You may use an instrument that 
uses an ultraviolet, non-dispersive infrared, fluorescence, or other 
detection principle to continuously measure SO2 in the 
gas stream and meets the performance specifications in Section 13.0. 
The low-range and dual-range analyzer provisions in Section 6.2.8.1 
of Method 7E apply.

7.0 Reagents and Standards

    7.1 Calibration Gas. What calibration gases do I need? Refer to 
Section 7.1 of Method 7E for the calibration gas requirements. 
Example calibration gas mixtures are listed below.
    (a) SO2 in nitrogen (N2).
    (b) SO2 in air.
    (c) SO2 and CO2 in N2.
    (d) SO2 andO2 in N2.
    (e) SO2/CO2/O2 gas mixture in 
N2.
    (f) CO2/NOX gas mixture in N2.
    (g) CO2/SO2/NOX gas mixture in 
N2.
    7.2 Interference Check. What additional reagents do I need for 
the interference check? The test gases for the interference check 
are listed in Table 7E-3 of Method 7E. For the alternative 
interference check, you must use the reagents described in Section 
7.0 of Method 6.

8.0 Sample Collection, Preservation, Storage, and Transport

    8.1 Sampling Site and Sampling Points. You must follow the 
procedures of Section 8.1 of Method 7E.
    8.2 Initial Measurement System Performance Tests. You must 
follow the procedures in Section 8.2 of Method 7E. If a dilution-
type measurement system is used, the special considerations in 
Section 8.3 of Method 7E also apply.
    8.3 Interference Check. You must follow the procedures of 
Section 8.2.7 of Method 7E to conduct an interference check, 
substituting SO2 for NOX as the method 
pollutant. For dilution-type measurement systems, you must use the 
alternative interference check procedure in Section 16 and a co-
located, unmodified Method 6 sampling train.
    8.4 Sample Collection. You must follow the procedures of Section 
8.4 of Method 7E.
    8.5 Post-Run System Bias Check and Drift Assessment. You must 
follow the procedures of Section 8.5 of Method 7E.

9.0 Quality Control

    Follow quality control procedures in Section 9.0 of Method 7E.

10.0 Calibration and Standardization

    Follow the procedures for calibration and standardization in 
Section 10.0 of Method 7E.

11.0 Analytical Procedures

    Because sample collection and analysis are performed together 
(see Section 8), additional discussion of the analytical procedure 
is not necessary.

12.0 Calculations and Data Analysis

    You must follow the applicable procedures for calculations and 
data analysis in Section 12.0 of Method 7E as applicable, 
substituting SO2 for NOX as appropriate.

13.0 Method Performance

    13.1 The specifications for the applicable performance checks 
are the same as in Section 13.0 of Method 7E.
    13.2 Alternative Interference Check. The results are acceptable 
if the difference between the Method 6C result and the modified 
Method 6 result is less than 7.0 percent of the Method 6 result for 
each of the three test runs. For the purposes of comparison, the 
Method 6 and 6C results must be expressed in the same units of 
measure.

14.0 Pollution Prevention [Reserved]

15.0 Waste Management [Reserved]

16.0 Alternative Procedures

    16.1 Alternative Interference Check. You may perform an 
alternative interference check consisting of at least three 
comparison runs between Method 6C and Method 6. This check validates 
the Method 6C results at each particular facility of known potential 
interferences. When testing under conditions of low concentrations 
(< 15 ppm), this alternative interference check is not allowed.

    Note: The procedure described below applies to non-dilution 
sampling systems only. If this alternative interference check is 
used for a dilution sampling system, use a standard Method 6 
sampling train and extract the sample directly from the exhaust 
stream at points collocated with the Method 6C sample probe.


[[Page 28089]]


    (1) Build the modified Method 6 sampling train (flow control 
valve, two midget impingers containing 3 percent hydrogen peroxide, 
and dry gas meter) shown in Figure 6C-1. Connect the sampling train 
to the sample bypass discharge vent. Record the dry gas meter 
reading before you begin sampling. Simultaneously collect modified 
Method 6 and Method 6C samples. Open the flow control valve in the 
modified Method 6 train as you begin to sample with Method 6C. 
Adjust the Method 6 sampling rate to 1 liter per minute (.10 
percent). The sampling time per run must be the same as for Method 6 
plus twice the average measurement system response time. If your 
modified Method 6 train does not include a pump, you risk biasing 
the results high if you over-pressurize the midget impingers and 
cause a leak. You can reduce this risk by cautiously increasing the 
flow rate as sampling begins.
    (2) After completing a run, record the final dry gas meter 
reading, meter temperature, and barometric pressure. Recover and 
analyze the contents of the midget impingers using the procedures in 
Method 6. You must analyze performance audit samples as described in 
Method 6 with this interference check. Determine the average gas 
concentration reported by Method 6C for the run.

17.0 References

    1. ``EPA Traceability Protocol for Assay and Certification of 
Gaseous Calibration Standards'' September 1997 as amended, EPA-600/
R-97/121

18.0 Tables, Diagrams, Flowcharts, and Validation Data
[GRAPHIC] [TIFF OMITTED] TR15MY06.000

* * * * *

Method 7E--Determination of Nitrogen Oxides Emissions From Stationary 
Sources (Instrumental Analyzer Procedure)

1.0 Scope and Application

What is Method 7E?

    Method 7E is a procedure for measuring nitrogen oxides 
(NOX) in stationary source emissions using a continuous 
instrumental analyzer. Quality assurance and quality control 
requirements are included to assure that you, the tester, collect 
data of known quality. You must document your adherence to these 
specific requirements for equipment, supplies, sample collection and 
analysis, calculations, and data analysis. This method does not 
completely describe all equipment, supplies, and sampling and 
analytical procedures you will need but refers to other methods for 
some of the details. Therefore, to obtain reliable results, you 
should also have a thorough knowledge of these additional test 
methods which are found in appendix A to this part:
    (a) Method 1--Sample and Velocity Traverses for Stationary 
Sources.
    (b) Method 4--Determination of Moisture Content in Stack Gases.
    1.1 Analytes. What does this method determine? This method 
measures the concentration of nitrogen oxides as NO2.

------------------------------------------------------------------------
            Analyte                  CAS No.           Sensitivity
------------------------------------------------------------------------
Nitric oxide (NO)..............      10102-43-9  Typically <2% of
Nitrogen dioxide (NO2).........      10102-44-0  Calibration Span.
------------------------------------------------------------------------

    1.2 Applicability. When is this method required? The use of 
Method 7E may be required by specific New Source Performance 
Standards, Clean Air Marketing rules, State Implementation Plans, 
and permits where measurement of NOX concentrations in 
stationary source emissions is required, either to determine 
compliance with an applicable emissions standard or to conduct 
performance testing of a continuous monitoring system (CEMS). Other 
regulations may also require the use of Method 7E.
    1.3 Data Quality Objectives (DQO). How good must my collected 
data be? Method 7E is designed to provide high-quality data for 
determining compliance with Federal and State emission standards and 
for relative accuracy testing of CEMS. In these and other 
applications, the principal objective is to ensure the accuracy of 
the data at the actual emission levels encountered. To meet this 
objective, the use of EPA traceability protocol calibration gases 
and measurement system performance tests are required.
    1.4 Data Quality Assessment for Low Emitters. Is performance 
relief granted when testing low-emission units? Yes. For low-
emitting sources, there are alternative performance specifications 
for analyzer calibration error, system bias, drift, and

[[Page 28090]]

response time. Also, the alternative dynamic spiking procedure in 
Section 16 may provide performance relief for certain low-emitting 
units.

2.0 Summary of Method

    In this method, a sample of the effluent gas is continuously 
sampled and conveyed to the analyzer for measuring the concentration 
of NOX. You may measure NO and NO2 separately 
or simultaneously together but, for the purposes of this method, 
NOX is the sum of NO and NO2. You must meet 
the performance requirements of this method to validate your data.

3.0 Definitions

    3.1 Analyzer Calibration Error, for non-dilution systems, means 
the difference between the manufacturer certified concentration of a 
calibration gas and the measured concentration of the same gas when 
it is introduced into the analyzer in direct calibration mode.
    3.2 Calibration Curve means the relationship between an 
analyzer's response to the injection of a series of calibration 
gases and the actual concentrations of those gases.
    3.3 Calibration Gas means the gas mixture containing 
NOX at a known concentration and produced and certified 
in accordance with ``EPA Traceability Protocol for Assay and 
Certification of Gaseous Calibration Standards,'' September 1997, as 
amended August 25, 1999, EPA-600/R-97/121 or more recent updates. 
The tests for analyzer calibration error, drift, and system bias 
require the use of calibration gas prepared according to this 
protocol.
    3.3.1 Low-Level Gas means a calibration gas with a concentration 
that is less than 20 percent of the calibration span and may be a 
zero gas.
    3.3.2 Mid-Level Gas means a calibration gas with a concentration 
that is 40 to 60 percent of the calibration span.
    3.3.3 High-Level Gas means a calibration gas with a 
concentration that is equal to the calibration span.
    3.4 Calibration Span means the upper limit of valid instrument 
response during sampling. To the extent practicable, the measured 
emissions should be between 20 to 100 percent of the selected 
calibration span
    3.5 Centroidal Area means the central area of the stack or duct 
that is no greater than 1 percent of the stack or duct cross 
section. This area has the same geometric shape as the stack or 
duct.
    3.6 Converter Efficiency Gas means a calibration gas with a 
known NO or NO2 concentration and of Traceability 
Protocol quality.
    3.7 Data Recorder means the equipment that permanently records 
the concentrations reported by the analyzer.
    3.8 Direct Calibration Mode means introducing the calibration 
gases directly into the analyzer (or into the assembled measurement 
system at a point downstream of all sample conditioning equipment) 
according to manufacturer's recommended calibration procedure. This 
mode of calibration applies to non-dilution-type measurement 
systems.
    3.9 Drift means the difference between the measurement system 
readings obtained in the pre-run and post-run system bias (or system 
calibration error) checks at a specific calibration gas 
concentration level (i.e. low-, mid-, or high-).
    3.10 Gas Analyzer means the equipment that senses the gas being 
measured and generates an output proportional to its concentration.
    3.11 Interference Check means the test to detect analyzer 
responses to compounds other than the compound of interest, usually 
a gas present in the measured gas stream, that is not adequately 
accounted for in the calibration procedure and may cause measurement 
bias.
    3.12 Low-Concentration Analyzer means any analyzer that operates 
with a calibration span of 20 ppm NOX or lower. Each 
analyzer model used routinely to measure low NOX 
concentrations must pass a Manufacturer's Stability Test (MST). A 
MST subjects the analyzer to a range of potential effects to 
demonstrate its stability following the procedures provided in 40 
CFR 53.23, 53.55, and 53.56 and provides the information in a 
summary format. A copy of this information must be included in each 
test report. Table 7E-5 lists the criteria to be met.
    3.13 Measurement System means all of the equipment used to 
determine the NOX concentration. The measurement system 
comprises six major subsystems: Sample acquisition, sample 
transport, sample conditioning, calibration gas manifold, gas 
analyzer, and data recorder.
    3.14 Response Time means the time it takes the measurement 
system to respond to a change in gas concentration occurring at the 
sampling point when the system is operating normally at its target 
sample flow rate or dilution ratio.
    3.15 Run means a series of gas samples taken successively from 
the stack or duct. A test normally consists of a specific number of 
runs.
    3.16 System Bias means the difference between a calibration gas 
measured in direct calibration mode and in system calibration mode. 
System bias is determined before and after each run at the low- and 
mid- or high-concentration levels. For dilution-type systems, pre- 
and post-run system calibration error is measured, rather than 
system bias.
    3.17 System Calibration Error applies to dilution-type systems 
and means the difference between the measured concentration of low-, 
mid-, or high-level calibration gas and the certified concentration 
for each gas when introduced in system calibration mode. For 
dilution-type systems, a 3-point system calibration error test is 
conducted in lieu of the analyzer calibration error test, and 2-
point system calibration error tests are conducted in lieu of system 
bias tests.
    3.18 System Calibration Mode means introducing the calibration 
gases into the measurement system at the probe, upstream of the 
filter and all sample conditioning components.
    3.19 Test refers to the series of runs required by the 
applicable regulation.

4.0 Interferences

    Note that interferences may vary among instruments and that 
instrument-specific interferences must be evaluated through the 
interference test.

5.0 Safety

    What safety measures should I consider when using this method? 
This method may require you to work with hazardous materials and in 
hazardous conditions. We encourage you to establish safety 
procedures before using the method. Among other precautions, you 
should become familiar with the safety recommendations in the gas 
analyzer user's manual. Occupational Safety and Health 
Administration (OSHA) regulations concerning cylinder and noxious 
gases may apply. Nitric oxide and NO2 are toxic and 
dangerous gases. Nitric oxide is immediately converted to 
NO2 upon reaction with air. Nitrogen dioxide is a highly 
poisonous and insidious gas. Inflammation of the lungs from exposure 
may cause only slight pain or pass unnoticed, but the resulting 
edema several days later may cause death. A concentration of 100 ppm 
is dangerous for even a short exposure, and 200 ppm may be fatal. 
Calibration gases must be handled with utmost care and with adequate 
ventilation. Emission-level exposure to these gases should be 
avoided.

6.0 Equipment and Supplies

    The performance criteria in this method will be met or exceeded 
if you are properly using equipment designed for this application.
    6.1 What do I need for the measurement system? You may use any 
equipment and supplies meeting the following specifications.
    (1) Sampling system components that are not evaluated in the 
system bias or system calibration error test must be glass, Teflon, 
or stainless steel. Other materials are potentially acceptable, 
subject to approval by the Administrator.
    (2) The interference, calibration error, and sys