Revisions to Test Method for Determining Stack Gas Velocity Taking Into Account Velocity Decay Near the Stack Walls, 42819-42831 [E9-20395]

Agencies

• ENVIRONMENTAL PROTECTION AGENCY

[Federal Register Volume 74, Number 163 (Tuesday, August 25, 2009)]
[Proposed Rules]
[Pages 42819-42831]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E9-20395]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 60

[EPA-HQ-OAR-2008-0697; FRL-8948-9]
RIN 2060-AP08


Revisions to Test Method for Determining Stack Gas Velocity 
Taking Into Account Velocity Decay Near the Stack Walls

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: EPA is proposing to revise the voluntary test method for 
determining stack gas velocity taking into account the velocity decay 
near the stack or duct walls. When the method was originally developed, 
it addressed only sources where the flow measurements were made in 
locations with circular cross-sections. The proposed revised test 
method addresses flow measurement locations with both circular and 
rectangular cross-sections. The proposed revisions also include changes 
that increase the accuracy of the method and simplify its application. 
The primary users of the proposed method are likely to be owners and 
operators of utility units subject to the Acid Rain

[[Page 42820]]

Program under Title IV of the Clean Air Act; and certain large electric 
generating units and large non-electric generating units that are 
subject to the nitrogen oxides (NOX) state implementation 
plan (SIP) call under Title I of the Clean Air Act. These sources use 
volumetric stack flow rate monitors in order to measure sulfur dioxide 
(SO2) and NOX mass emissions and unit heat input, 
and must conduct periodic relative accuracy test audits (RATAs) of the 
flow rate monitors at these units.

DATES: Comments must be received on or before October 26, 2009.

ADDRESSES: Submit your comments, identified by Docket ID Number EPA-HQ-
OAR-2008-0697, by one of the following methods:
     https://www.regulations.gov: Follow the on-line 
instructions for submitting comments.
     E-mail: a-and-r-Docket@epa.gov, Attention Docket ID No. 
EPA-HQ-OAR-2008-0697
     Fax: 202-566-9744, Attention Docket ID. No. EPA-HQ-OAR-
2008-0697.
     Mail: Air and Radiation Docket and Information Center, 
Environmental Protection Agency, Mail Code: 2822T, 1200 Pennsylvania 
Ave., NW., Washington, DC, 20460, Attention Docket ID No. EPA-HQ-OAR-
2008-0697. Please include a total of two copies.
     Hand Delivery: Deliver your comments to: EPA Docket 
Center, 1301 Constitution Ave., NW., Room 3334, Washington, DC 20460. 
Attention Docket ID No. EPA-HQ-OAR-2008-0697. Such deliveries are only 
accepted during the Docket's normal hours of operation, and special 
arrangements should be made for deliveries of boxed information.
    Instructions. Direct your comments to Docket ID No. EPA-HQ-OAR-
2008-0697. EPA's policy is that all comments received will be included 
in the public docket without change and may be made available online at 
https://www.regulations.gov including any personal information provided, 
unless the comment includes information claimed to be Confidential 
Business Information (CBI) or other information whose disclosure is 
restricted by statute. Do not submit information that you consider to 
be CBI or otherwise protected through https://www.regulations.gov or e-
mail. The https://www.regulations.gov Web site is an ``anonymous 
access'' system, which means EPA will not know your identity or contact 
information unless you provide it in the body of your comment. If you 
send an e-mail comment directly to EPA without going through https://www.regulations.gov, your e-mail address will be automatically captured 
and included as part of the comment that is placed in the public docket 
and made available on the Internet. If you submit an electronic 
comment, EPA recommends that you include your name and other contact 
information in the body of your comment and with any disk or CD-ROM you 
submit. If EPA cannot read your comment due to technical difficulties 
and cannot contact you for clarification, EPA may not be able to 
consider your comment. Electronic files should avoid the use of special 
characters, any form of encryption, and be free of any defects or 
viruses. For additional information about EPA's public docket, visit 
the EPA Docket Center homepage at https://www.epa.gov/epahome/dockets.htm.
    Docket. All documents in the docket are listed in the https://www.regulations.gov index. 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, will be publicly available only in hard copy. 
Publicly available docket materials are available either electronically 
in https://www.regulations.gov or in hard copy at the Air and Radiation 
Docket and Information Center, EPA/DC, EPA West Building, Room 3334, 
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 Docket is (202) 
566-1742.

FOR FURTHER INFORMATION CONTACT: Mr. Jason M. DeWees, US EPA, Office of 
Air Quality Planning and Standards, Air Quality Assessment Division, 
Measurement Technology Group (E143-02), Research Triangle Park, NC 
27711; telephone (919) 541-9724; fax number (919) 541-0516; e-mail 
address dewees.jason@epa.gov.

SUPPLEMENTARY INFORMATION: 

Table of Contents

I. Does This Action Apply to Me?
II. What Should I Consider as I Prepare My Comments for EPA?
III. Where Can I Obtain a Copy of This Action?
IV. Background
V. Why Is EPA Revising Method 2H?
VI. Statutory and Executive Order Reviews
    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 Risks and Safety Risks
    H. Executive Order 13211, Actions that Significantly Affect 
Energy Supply, Distribution, or Use
    I. National Technology Transfer and Advancement Act
    J. Executive Order 12898--Federal Actions to Address 
Environmental Justice in Minority Populations and Low-Income 
Populations

I. Does This Action Apply to Me?

    Entities potentially affected by this action include those listed 
in Table 1.

                              Table 1--Entities Potentially Affected by This Action
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                    Category                       NAICS \a\             Examples of regulated entities
----------------------------------------------------------------------------------------------------------------
Industry........................................       221112  Fossil fuel-fired electric utility steam
                                                                generating units.
Federal government..............................   \b\ 221122  Fossil fuel-fired electric utility steam
                                                                generating units owned by the Federal
                                                                government.
State/local governments.........................   \b\ 221122  Fossil fuel-fired electric utility steam
                                                                generating units owned by municipalities.
Tribal governments..............................       921150  Fossil fuel-fired electric utility steam
                                                                generating units in Indian country.
----------------------------------------------------------------------------------------------------------------
\a\ North American Industry Classification System.
\b\ Federal, State, or local government-owned and operated establishments are classified according to the
  activity in which they are engaged.

    This table is not intended to be exhaustive, but rather provides a 
guide for readers regarding entities likely to be affected by this 
proposed rule. If you have any questions regarding the applicability of 
this proposed rule to a particular entity, consult either the air 
permit authority for the entity or your

[[Page 42821]]

EPA regional representative as listed in 40 CFR 63.13.

II. What Should I Consider as I Prepare My Comments for EPA?

    1. Submitting CBI. Do not submit this information to EPA through 
https://www.regulations.gov or e-mail. Clearly mark any of the 
information that you claim to be CBI. For CBI information in a disk or 
CD ROM that you mail to EPA, mark the outside of the disk or CD ROM as 
CBI and then identify electronically within the disk or CD ROM the 
specific information that is claimed as CBI. In addition to one 
complete version of the comment that includes information claimed as 
CBI, a copy of the comment that does not contain the information 
claimed as CBI must be submitted for inclusion in the public docket. 
Information so marked will not be disclosed except in accordance with 
procedures set forth in 40 CFR part 2.
    2. Tips for Preparing Your Comments. When submitting comments, 
remember to:
     Identify the rulemaking by docket number and other 
identifying information (subject heading, Federal Register date and 
page number).
     Follow directions--The agency may ask you to respond to 
specific questions or organize comments by referencing a Code of 
Federal Regulations (CFR) part or section number.
     Explain why you agree or disagree, suggest alternatives, 
and substitute language for your requested changes.
     Describe any assumptions and provide any technical 
information and/or data that you used.
     If you estimate potential costs or burdens, explain how 
you arrived at your estimate in sufficient detail to allow for it to be 
reproduced.
     Provide specific examples to illustrate your concerns, and 
suggest alternatives.
     Explain your views as clearly as possible, avoiding the 
use of profanity or personal threats.
     Make sure to submit your comments by the comment period 
deadline identified.

III. Where Can I Obtain a Copy of This Action?

    In addition to being available in the docket, an electronic copy of 
this proposed rule is also available on the World Wide Web through the 
Technology Transfer Network (TTN). Following the Administrator's 
signature, a copy of this proposed rule will be posted 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.

IV. Background

    In 1999, EPA promulgated three new stack flow test methods (64 FR 
26484, May 14, 1999) designed to provide additional measurement options 
and increased accuracy by accounting for velocity decay at the wall and 
yaw and pitch angled flow. One of the methods, Determination of Stack 
Gas Velocity Taking Into Account Velocity Decay Near The Stack Wall 
(Method 2H), was intended to address an inherent bias when stack flow 
is measured in accordance with the equal area traverse procedure in 
Reference Method 1. The traverse point selection procedure in Method 1 
provided a reasonable assessment of the average flow in the central 
portion of the stack, but it did not account for viscous shear that 
causes the velocity to drop off significantly near the stack walls. 
Method 2H allowed sources to make near wall measurements in order to 
calculate a wall effects adjustment factor (WAF) to correct the test 
method flow to account for the velocity decay near the stack wall. 
Unfortunately, Method 2H could only be used on circular stacks. At that 
time, the effort focused on developing and testing a method for 
applications where flow is measured in stacks with circular cross-
sections, which represented the vast majority of the affected sources. 
The procedures did not address flow measurements in rectangular ducts 
even though the same viscous shear wall effect occurred in those 
locations, and the related bias was even more pronounced due to the 
geometry.
    In 2003, EPA released Conditional Test Method 041 (CTM-041) based 
on a method developed by Electric Power Research Institute (EPRI) to 
address wall effects when flow is measured in rectangular ducts. In 
addition to filling a void in the flow reference methods, CTM-041 
included a number of improvements over EPA Reference Method 2H. Since 
its release, the method has been successfully used by many sources 
through a petition process.

V. Why Is EPA Revising Method 2H?

    EPA proposes to revise Method 2H to incorporate the measurement and 
calculation procedures included in CTM-041 for rectangular duct flow 
measurement locations. EPA is proposing to make this change based on 
the results of the field-testing performed by EPRI during the method's 
initial development and the successful application of these procedures 
at many sources since the CTM-041 was released. Incorporating these 
procedures will eliminate the need for the petition process, which 
owner or operators of rectangular duct sources seeking to address wall 
effects related bias must currently use.
    The proposed revisions harmonize the procedures for circular and 
rectangular measurement locations and extend the improvements in CTM-
041 to circular stacks. The proposed revised method does not require 
testing at multiple loads since there is no apparent load or flow rate 
levels (Reynolds Number) related effect. Under the proposed revisions, 
WAF testing does not need to be coupled with a Relative Accuracy Test 
Audit (RATA), allowing some sources to avoid the potential difficulties 
and problems associated with trying to measure wall effects using 
Methods 2F or 2G. Since the factors that significantly influence wall 
effects will not change appreciably over time, a WAF can continue to be 
used unless major modifications are made to the duct or stack and the 
RATA continues to include the same number of traverse points on which 
the WAF was based.
    The logarithmic-overlap law has long been used to model flow near 
walls. As expected, the logarithmic-overlap law demonstrated excellent 
correlation with wall effects data from both agency and industry 
studies. The proposed revised method harnesses the accuracy of the 
logarithmic-overlap law in two ways. First, the proposed method 
includes an option where the logarithmic-overlap law is used to 
categorize near-wall velocities based on a limited number of 
measurements. This proposed approach solves a problem in the current 
method, where a full WAF assessment cannot be made if the ports 
protrude into the stack.
    Secondly, the logarithmic-overlap law is also used, along with a 
few conservative assumptions, to develop stack specific default WAF 
values. This proposed option yields conservative WAF values that, 
unlike the ``one-size-fits-all'' defaults in the current version of 
Method 2H, take into consideration stack or duct geometry and velocity 
profile issues. The stack specific default factors do not offer sources 
the full velocity correction of the full WAF assessment option, but the 
stack specific default factors option is a reasonable approach for 
applications where additional measurements would be difficult.
    Another proposed change to the method is the way the WAFs are 
applied under the revised method. Presently, the adjustment is applied

[[Page 42822]]

only to the RATA flow values. Under the revised method, the WAF is 
applied as an adjustment to the cross-sectional area value used both to 
calculate the continuous emissions monitors and reference method flows.

VI. Statutory and Executive Order Reviews

A. Executive Order 12866--Regulatory Planning and Reviews

    This proposed action is not a ``significant regulatory action'' 
under the terms of Executive Order 12866 (58 FR 51735, October 4, 1993) 
and is, therefore, not subject to review under the Executive Order.

B. Paperwork Reduction Act

    This proposed action does not impose an information collection 
burden under the provisions of the Paperwork Reduction Act, 44 U.S.C. 
3501 et seq. Burden is defined at 5 CFR 1320.3(b). The proposed 
amendments do not contain any reporting or recordkeeping requirements.

C. Regulatory Flexibility Act

    The RFA generally requires an agency to prepare a regulatory 
flexibility analysis of any rule subject to notice and comment 
rulemaking requirements under the Administrative Procedure Act or any 
other statute unless the agency certifies that the rule will not have a 
significant economic impact on a substantial number of small entities. 
Small entities include small businesses, small organizations, and small 
governmental jurisdictions.
    For purposes of assessing the impact of this proposed rule on small 
entities, small entity is defined as: (1) A small business as defined 
by the Small Business Administration's 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.
    After considering the economic impacts of this proposed rule on 
small entities, I certify that this action will not have a significant 
economic impact on a substantial number of small entities. This action 
proposes to revise the test method for velocity decay at the stack or 
duct wall in 40 CFR part 60, Appendix A-2. The use of this method is a 
voluntary addition to the required volumetric flow rate methods. 
Therefore, this action does not impose any requirements on small 
entities. The small entities affected by this proposed rule are small 
businesses, small governmental jurisdictions and small non-profits that 
operate facilities that currently voluntarily choose to use Method 2H. 
EPA anticipates that the proposed revised method will only be used by 
small entities if the use of the revised method results in overall cost 
savings due to the voluntary nature of the method.
    Although this proposed rule will not have a significant economic 
impact on a substantial number of small entities, EPA nonetheless has 
tried to reduce the impact of this rule on small entities.
    We continue to be interested in the potential impacts of the 
proposed rule on small entities and welcome comments on issues related 
to such impacts.

D. Unfunded Mandates Reform Act

    This action contains no Federal mandates under the provisions of 
Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), 2 U.S.C. 
1531-1538 for State, local, or tribal governments or the private 
sector. The action imposes no enforceable duty on any State, local or 
tribal governments or the private sector. Therefore, this action is not 
subject to the requirements of sections 202 or 205 of the UMRA. This 
action is also not subject to the requirements of section 203 of UMRA 
because it contains no regulatory requirements that might significantly 
or uniquely affect small governments. This action proposes to revise 
the test method for velocity decay at the stack or duct wall in 40 CFR 
part 60. The use of this method is a voluntary addition to the required 
volumetric flow rate methods.

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'' is 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 proposed 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. Because this method is an 
alternative method, its use is voluntary.
    In the spirit of Executive Order 13132, and consistent with EPA 
policy to promote communications between EPA and State and local 
governments, EPA specifically solicits comments on this proposed rule 
from State and local officials.

F. Executive Order 13175--Consultation and Coordination with Indian 
Tribal Governments

    This action does not have tribal implications, as specified in 
Executive Order 13175 (65 FR 67249, November 9, 2000). In this action, 
EPA is simply proposing to revise an existing, optional test method. 
Thus, Executive Order 13175 does not apply to this rule.
    EPA specifically solicits additional comment on this proposed 
action from tribal officials.

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

    EPA interprets Executive Order 13045 (62 FR 29885, April 23, 1997) 
as applying only to those regulatory actions that concern 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 
action is not subject to Executive Order 13045 because it does not 
establish an environmental standard intended to mitigate 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 (66 FR 28355 
(May 22, 2001)), because it is not a significant regulatory action 
under Executive Order 12866.

I. National Technology Transfer and Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (``NTTAA''), Public Law 104-113, 12(d) (15 U.S.C. 272 note) 
directs EPA to use voluntary consensus standards in its 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, and business practices) that are developed or adopted by 
voluntary consensus standards

[[Page 42823]]

bodies. NTTAA directs EPA to provide Congress, through OMB, 
explanations when the Agency decides not to use available and 
applicable voluntary consensus standards.
    EPA is not proposing a new test method in this rulemaking but is 
revising an existing optional method that is used in conjunction with 
methods already mandated for evaluating compliance with current 
emission standards. EPA is not aware of any voluntary consensus 
standards that would address the specific need. Therefore, EPA is not 
considering the use of any voluntary consensus standards.

J. Executive Order 12898--Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations

    Executive Order 12898 (59 FR 7629, February 16, 1994) establishes 
federal executive policy on environmental justice. Its main provision 
directs federal agencies, to the greatest extent practicable and 
permitted by law, to make environmental justice part of their mission 
by identifying and addressing, as appropriate, disproportionately high 
and adverse human health or environmental effects of their programs, 
policies, and activities on minority populations and low-income 
populations in the United States.
    EPA has determined that this proposed rule will not have 
disproportionately high and adverse human health or environmental 
effects on minority or low-income populations because it does not 
affect the level of protection provided to human health or the 
environment.
    This action only revises an existing optional method that is used 
in conjunction with methods already mandated for evaluating compliance 
with current emission standards.

List of Subjects in 40 CFR Part 60

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

    Dated: August 18, 2009.
Lisa P. Jackson,
Administrator.
    For the reasons set out in the preamble, title 40, chapter I of the 
Code of Federal Regulations is proposed to be amended as follows:

PART 60--STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES

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

    Authority:  42 U.S.C. 7410, 7414, 7421, 7470-7479, 7491, 7492, 
7601 and 7602.

    2. Amend Appendix A-2 by revising Method 2H to read as follows:

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

* * * * *

Method 2H--Determination of STACK GAS VELOCITY Taking Into Account 
Velocity Decay Near the Stack Walls

1.0 Scope and Application

    1.1 This method may be applied when determining volumetric flow 
to account for velocity decay near the walls. Adherence to the 
requirements of this method will enhance the quality of the data 
obtained from air pollutant sampling methods.
    1.2 This method includes provisions to account for wall effects 
at circular stack and rectangular duct measurement locations. If the 
reference method flow is measured in a stack with a circular cross 
section, follow the procedures in this method for circular stacks. 
If the reference method flow is measured in a duct with a 
rectangular cross section follow the procedures in this method for 
rectangular ducts. All provisions in this method apply to both 
circular stack and rectangular duct measurement applications unless 
otherwise specified.
    1.3 This method is not applicable for testing circular stacks or 
ducts less than 3.3 ft (1.0 m) in diameter, or rectangular stacks or 
ducts less than 8.5 ft\2\ (0.79 m\2\) in area.
    [The terms ``stack'' and ``duct'' are and can be used 
interchangeably throughout this method.]

2.0 Summary of Method

    2.1 A wall effects adjustment factor (WAF) is determined. The 
WAF is used to adjust the cross-sectional area value used to 
calculate volumetric flow based on reference method or continuous 
emission monitoring system (CEMS) gas velocity measurements to take 
into account velocity decay near the stack or duct walls.
    2.2 The method contains a calculation approach to derive wall 
effects adjustment factors based on either measured velocities or a 
combination of measured and modeled velocities. The method also 
contains procedures to determine a duct or stack specific default 
based on conservative velocity estimates, requiring no additional 
velocity measurements. Unless a duct or stack specific default is 
used, any adjustment factor must be based on at least three wall 
effect test runs.
    2.3 The wall effects test may be conducted as part of a relative 
accuracy test audit (RATA) or as a separate test procedure. Any WAF 
that is derived using this procedure can only be applied to 
calculate volumetric flows in conjunction with velocity values from 
RATAs consisting of the same number (or fewer) of Method 1 of 
Appendix A-1 traverse points used to determine the WAF or from a 
CEMS for which such a RATA has been conducted. A wall effects test 
must be completed whenever the stack or ductwork is altered such 
that the flow profile is significantly changed.

3.0 Definitions

    3.1 dlast means, depending on context, either (1) the distance 
from the wall of the last one-inch incremented wall effects traverse 
point or (2) the traverse point located at that distance (see 
Figures 2H-3 and 2H-4).
    3.2 drem means, depending on context, either (1) the distance 
from the wall of the centroid of the area between dlast 
and the interior edge of the Method 1 of Appendix A-1 equal-area 
sector closest to the wall or (2) the traverse point located at that 
distance (see Figure 2H-3). For rectangular duct measurement 
locations, more than one drem point may be required (see 
Figure 2H-4):
    3.2.1 dremy represents drem for the wall 
perpendicular to the test port wall.
    3.2.2 dremx represents drem for the test 
port wall.
    3.2.3 dremc represents drem for the Method 
1 corner equal-area sector.
    3.3 ``May,'' ``Must,'' ``Shall,'' ``Should,'' and the imperative 
form of verbs.
    3.3.1 ``May'' is used to indicate that a provision of this 
method is optional.
    3.3.2 ``Must,'' ``Shall,'' and the imperative form of verbs 
(such as ``record'' or ``enter'') are used to indicate that a 
provision of this method is mandatory.
    3.3.3 ``Should'' is used to indicate that a provision of this 
method is not mandatory but is highly recommended as good practice.
    3.4 Method 1 refers to 40 CFR Part 60, Appendix A-1, ``Method 1-
Sample and Velocity Traverses for Stationary Sources.''
    3.5 Method 2 refers to 40 CFR Part 60, Appendix A-1, ``Method 2-
Determination of Stack Gas Velocity and Volumetric Flow Rate (Type S 
Pitot Tube).''
    3.6 Method 2F refers to 40 CFR Part 60, Appendix A-1, ``Method 
2F-Determination of Stack Gas Velocity and Volumetric Flow Rate with 
Three-Dimensional Probes.''
    3.7 Method 2G refers to 40 CFR Part 60, Appendix A-2, ``Method 
2G-Determination of Stack Gas Velocity and Volumetric Flow Rate with 
Two-Dimensional Probes.''
    3.8 One-inch incremented wall effects traverse point means any 
of the wall effects traverse points that are located at one-inch 
intervals, i.e., traverse points d1 through 
dlast (see Figures 2H-3 and 2H-4).
    3.9 Opposing test port wall means the wall that is parallel to 
the test port wall on the opposite side of the duct or stack.
    3.10 Relative accuracy test audit (RATA) is a field test 
procedure performed in a stack or duct in which a series of 
concurrent measurements of the same effluent stream is taken by a 
reference method and an installed monitoring system. A RATA usually 
consists of a series of 9 to 12 sets of such concurrent 
measurements, each of which is referred to as a RATA run. In a 
volumetric flow RATA, each reference method run consists of a 
complete traverse of the stack or duct.

[[Page 42824]]

    3.11 Test port wall means the wall of the duct or stack in which 
test ports are mounted.
    3.12 Wall effects unadjusted average velocity means the average 
gas velocity, not accounting for velocity decay near the wall, as 
determined in accordance with Method 2, 2F, or 2G for a Method 1 
traverse.
    3.13 Wall effects adjusted average velocity means the average 
gas velocity, taking into account velocity decay near the wall, as 
calculated from measurements at the Method 1 traverse points and at 
the additional wall effects traverse points specified in this 
method.
    3.14 Wall effects traverse point means a traverse point located 
in accordance with Section 8.1.2 of this method.

4.0 Interferences [Reserved]

5.0 Safety

    This method may involve hazardous materials, operations, and 
equipment. This method does not purport to address all of the health 
and safety considerations associated with its use. It is the 
responsibility of the user of this method to establish appropriate 
health and safety practices and to determine the applicability of 
occupational health and safety regulatory requirements prior to 
performing this method.

6.0 Equipment and Supplies

    The provisions pertaining to equipment and supplies in the 
method that is used to take the traverse point measurements (i.e., 
Method 2, 2F, or 2G of Appendix A-1 and A-2) are applicable under 
this method.

7.0 Reagents and Standards [Reserved]

8.0 Sample Collection and Analysis

    8.1 Traverse Point Locations and Measurements. Conduct 
measurements at Method 1 of Appendix A-1 and wall effects traverse 
points in accordance with Method 2, 2F, or 2G of Appendix A-1 and A-
2 and Section 8.2 of this method. Determine the location of the 
Method 1 of Appendix A-1 traverse points in accordance with Section 
8.1.1, and the location of the wall effects traverse points in 
accordance with Section 8.1.2. The alternative procedures of Section 
8.3 may be used in lieu of performing all the measurements specified 
in this section. All traverse points are determined with respect to 
the test ports used when conducting RATAs.
    8.1.1 Method 1 equal-area traverse point locations. Determine 
the location of the Method 1 of Appendix A-1 equal-area traverse 
points using Table 1-1 (Cross Section Layout for Rectangular Stacks) 
or Table 1-2 (Location of Traverse Points in Circular Stacks) in 
Method 1 of Appendix A-1, as appropriate, and the procedure 
described in Section 11.3 of Method 1 of Appendix A-1.
    8.1.2 Wall effects traverse point locations. Measurements must 
be taken at the following points from at least four test ports. 
Measurements may be taken from any available test port, provided 
that all measurements are made in the same test plane and that at 
least four test ports are used. For the purpose of this method, near 
wall measurements are excluded from test ports where the flow is 
disturbed at a required traverse point located in the equal area 
nearest the test port wall because upstream cross-bracing (or some 
other disturbance) near the traverse location is directly in-line 
with the required traverse point. If necessary or desired, near wall 
measurements can be made from ports located on more than one duct 
wall on rectangular ducts or stacks.
    8.1.2.1 Circular stack wall effects traverse point locations:
    (a) One-inch increments from the wall. At least one increment 
point must be measured. Measurements may be taken at any number of 
additional one-inch increments, provided that each point must be 
located at a distance that is a whole number (e.g., 1, 2, 3) 
multiple of 1 in. (2.5 cm) from the wall and that no one-inch 
intervals are omitted between increments.
    (b) drem, as determined using Equation 2H-1.
    (c) dM1, the distance of the first Method 1 of Appendix A-1 
equal area traverse point closest from the test port wall. 
Measurements need not be repeated if already required under Section 
8.1.1.
    8.1.2.2 Rectangular duct wall effects traverse point locations:
    (a) One-inch increments from the wall. At least one increment 
point must be measured. Measurements may be taken at any number of 
additional one-inch increments, provided that each point must be 
located at a distance that is a whole number (e.g., 1, 2, 3) 
multiple of 1 in. (2.5 cm) from the wall and that no one-inch 
intervals are omitted between increments.
    (d) dremx, as determined using Equation 2H-3.
    (e) dremy, as determined using Equation 2H-5.
    (f) dM1y, the distance between the wall perpendicular 
to the test port wall and the centroid of the Method 1 exterior 
equal-area sector adjacent to that wall as determined using Equation 
2H-7.
    (g) dM1, the distance of the first Method 1 of Appendix A-1 
equal area traverse point closest from the test port wall. 
Measurements need not be repeated if already required under Section 
8.1.1.
    8.1.2.3 If the probe cannot be positioned at 1 in. (2.5 cm) from 
the wall (e.g., because of insufficient room to withdraw the probe 
shaft) or if the flue gas velocity cannot be measured at 1 in. (2.5 
cm) from the wall because the port extends beyond the wall into the 
stack or duct, take measurements at the one-inch incremented wall 
effects traverse point closest to the wall where the probe can be 
positioned and the velocity probe head clears the port. It should be 
noted that the full extent of velocity decay may not be accounted 
for if measurements cannot be made at the 1-in. incremented wall 
effects traverse points closest to the wall.
    8.1.2.4 For circular stack measurement locations, calculate the 
distance drem to within \1/4\ in. (6.4 mm):
[GRAPHIC] [TIFF OMITTED] TP25AU09.003

Where:

r = stack or duct radius in in. (cm)
p = the number of Method 1 of Appendix A-1 equal area traverse 
points on a diameter, (e.g., for a 16-point traverse, p = 8)

    8.1.2.5 For circular stack measurement locations, the last one-
inch interval, dlast, must not be closer to the center of the stack 
or duct than the distance of the interior boundary, db, of the 
Method 1 of Appendix A-1 equal area closest to the wall. That is, 
dlast <= db, where:
[GRAPHIC] [TIFF OMITTED] TP25AU09.004

    8.1.2.6 For rectangular duct measurement locations, calculate 
the following distances to within \1/4\ in. (6.4 mm):
[GRAPHIC] [TIFF OMITTED] TP25AU09.005

(a) drem
Where:

dbx = the distance from the test port wall to the interior edge of 
the Method 1 of Appendix A-1 equal-area sector closest to that wall 
(Equation 2H-4)
dlast = the distance from the test port wall to the last one-inch 
measurement farthest from that wall as defined in Section 3.1. (If 
dlast > dbx, then substitute the greatest one-inch interval less 
than or equal to dbx in the preceding equation to calculate dremx.)
[GRAPHIC] [TIFF OMITTED] TP25AU09.006

Where:

Lx = length of the duct or stack in the direction perpendicular to 
the test port wall (see Figure 2H-2)
Px = number of traverse points at each test port as determined by 
Method 1 of Appendix A-1

(b) dremy

[[Page 42825]]

[GRAPHIC] [TIFF OMITTED] TP25AU09.007

Where:

dby = the distance from the wall perpendicular to the test port wall 
to the interior edge of the Method 1 of Appendix A-1 equal-area 
sector closest to that wall (Equation 2H-6)
dlast = the distance from the test port wall to the last one-inch 
measurement farthest from that wall as defined in Section 3.1. (If 
dlast > dby, then substitute the greatest one-inch interval less 
than or equal to dby in the preceding equation to calculate dremy.)
[GRAPHIC] [TIFF OMITTED] TP25AU09.008

Where:

Ly = length of the duct or stack in the direction parallel to the 
test port wall (see Figure 2H-2)
Py = number of test ports required by Method 1 of Appendix A-1 along 
a single wall

(c) dM1y
[GRAPHIC] [TIFF OMITTED] TP25AU09.009

    8.1.3 Special considerations. The following special 
considerations apply when the distance between traverse points is 
less than or equal to \1/2\ in. (12.7 mm).
    8.1.3.1 A wall effects traverse point and the Method 1 of 
Appendix A-1 traverse point. If the distance between a wall effects 
traverse point and the Method 1 of Appendix A-1 traverse point is 
less than or equal to \1/2\ in. (12.7 mm), taking measurements at 
both points is allowed but not required or recommended. If 
measurements are taken at only one point, take the measurements at 
the point that is farther from the wall, and use the velocity 
obtained at that point as the value for both points.
    8.1.3.2 drem and dlast. If the distance between dlast and drem 
(or, for rectangular ducts, dremx, dremy, or dremc) is less than or 
equal to \1/2\ in. (12.7 mm), taking measurements at drem is allowed 
but not required or recommended. If measurements are not taken at 
drem, the measured velocity value at dlast must be used as the value 
for both dlast and drem.
    8.1.3.3 dremx and dremy. If the distance between the two drem 
points is less than or equal to \1/2\ in (12.7 mm), taking 
measurements at each of the affected points is allowed but not 
required or recommended. If measurements are not taken at each of 
the affected drem points, the measured velocity may be taken at one 
of them and substituted for the remaining point.
    8.2 Traverse Point Sampling Order and Probe Selection. Determine 
the sampling order of the Method 1 of Appendix A-1 and wall effects 
traverse points, and select the appropriate probe(s) for the 
measurements, taking into account the following considerations.
    8.2.1 To reduce the likelihood of velocity variation and its 
potential impact on the wall effect determinations, the following 
provisions of this method shall be met.
    8.2.1.1 All wall effects traverse points specified in Section 
8.1.2 shall be sampled without interruption.
    8.2.1.2 During each run, the entire integrated Method 1 and wall 
effects traverse across all test ports shall be as short as 
practicable.
    8.2.2 The same type of probe must be used to take measurements 
at all Method 1 of Appendix A-1 and wall effects traverse points. 
However, different probes of the same type may be used at different 
ports (e.g., Type S probe 1 at port A, Type S probe 2 at port B) or 
at different traverse points accessed from a particular port (e.g., 
Type S probe 1 for Method 1 of Appendix A-1 interior traverse points 
accessed from port A, Type S probe 2 for wall effects traverse 
points and the Method 1 of Appendix A-1 exterior traverse point 
accessed from port A). The identification number of the probe used 
to obtain measurements at each traverse point must be recorded.
    8.3 Alternative Measurement Reduction Approaches (Optional). The 
following alternatives may be used to reduce the number of 
measurements required to calculate WAF values. The velocities 
calculated using these alternative approaches will be used in 
conjunction with the procedures in Section 12 to determine WAF 
values.
    8.3.1 In lieu of taking measurements at each point, Equation 2H-
8 may be used to calculate velocities for each one-inch interval and 
all other points (e.g., dremx) that are less than 12 in. 
(30 cm) from the test port wall based on the velocity measured at 
the first available one-inch interval that is at least two in. from 
the wall and the velocity measured 12 in. (30 cm) from the wall.
[GRAPHIC] [TIFF OMITTED] TP25AU09.010

Where:

Vd = velocity at distance d from wall, ft/s (m/s)
V1 = velocity measured at the closest available one-inch 
interval that is at least two in. from the wall, ft/s (m/s)
V2 = velocity measured at a distance of 12 in. (30 cm) 
from the wall, ft/s (m/s)
y1 = distance of the closest available one-inch interval 
that is at least two in. from the wall, in. (cm/2.54)
d = distance d from wall, in. (cm/2.54)

    8.3.2 Duct or stack specific WAF default values may be 
determined in conjunction with the procedures of Section 12 using 
velocity values calculated in the following manner.
[GRAPHIC] [TIFF OMITTED] TP25AU09.011

Where:
Vd = velocity at distance d from wall, ft/s (m/s)
V2 = velocity measured at the first regular equal area 
traverse point, ft/s (m/s)
y2 = reference distance determined in accordance with 
8.3.2(a) or (b), in. (cm/2.54)
d = distance d from wall, in. (cm/2.54)

    (a) Calculate the velocity at the near wall one-inch intervals 
(1 in. to 12 in.) using Equation 2H-9. Use y2 = distance 
from the wall of the first Method 1 of Appendix A-1 equal area 
traverse point minus 0.5 in. (1.27 cm) unless the distance is 
greater than 12 in. (30 cm) then use y2 = 12 in. (30 cm). 
If y2 is less than one in. (2.54 cm), use y2 = 
1 in. (2.54 cm).
    (b) Calculate the velocities at the drem, 
dremx, dremy, and dM1y locations 
using Equation 2H-9. Use y2 = distance from the wall of 
the first regular equal area traverse point. If the respective 
distance (drem, dremx, dremy, or 
dM1y) is greater than 12 in. (30 cm) but less than the 
distance from the wall of the first Method 1 of Appendix A-1 equal 
area traverse point, substitute the velocity measured at the first 
Method 1 of Appendix A-1 equal area traverse point for desired 
velocity.

9.0 Quality Control

    9.1 Verifying Traverse Point Distances. In taking measurements 
at wall effects traverse

[[Page 42826]]

points, it is very important for the probe impact pressure port to 
be positioned as close as practicable to the traverse point 
locations in the gas stream. For this reason, before beginning wall 
effects testing, it is important to calculate and record the 
traverse point positions that will be marked on each probe (or 
programmed for automated probes) for each port, taking into account 
the distance that each port nipple (or probe mounting flange for 
automated probes) extends out of the stack or duct and any extension 
of the port nipple (or mounting flange) into the gas stream. Ensure 
that the distance of each mark from the center of the probe impact 
pressure port agrees with the previously calculated traverse point 
positions to within  \1/2\ in. (6.4 mm).
    9.2 Probe Installation. Properly sealing the port area is 
particularly important in taking measurements at wall effects 
traverse points. For testing involving manual probes, the area 
between the probe sheath and the port should be sealed with a 
tightly fitting flexible seal made of an appropriate material such 
as heavy cloth so that leakage is minimized. For automated probe 
systems, the probe assembly mounting flange area should be checked 
to verify that there is no leakage.
    9.3 Velocity Stability. This method should be performed only 
when the average gas velocity in the stack or duct is relatively 
constant over the duration of the test. If the average gas velocity 
changes significantly during the course of a wall effects test, the 
test results should be discarded.

10.0 Calibration

    The calibration coefficient(s) or curves obtained under Method 
2, 2F, or 2G of Appendix A-1 and A-2 and used to perform the Method 
1 of Appendix A-1 traverse are applicable under this method.

11.0 Analytical Procedure

    Sample collection and analysis are concurrent for this method 
(see Section 8).

12.0 Data Analysis and Calculations

    The following calculations shall be performed to obtain a WAF.
    12.1 Nomenclature. The following terms are listed in the order 
in which they appear in Equations 2H-10 through 2H-23.

vX = stack or duct gas point velocity value, adjusted for 
wall effects, at Method 1 of Appendix A-1 traverse point location 
(dM1) for the exterior equal-area sectors adjacent to the test port 
wall, actual ft/sec (m/sec);
vd = the measured stack gas velocity at distance d from the wall, 
actual ft/sec (m/sec); Note: v0 = 0;
r = stack or duct radius in in. (cm)
d = distance of a 1-in. incremented wall effects traverse point from 
the wall, for traverse points d1 through dlast, in. (cm);
[delta] = distance between one-inch intervals, 1 in., (2.5 cm);
vdrem = the measured stack gas velocity at distance drem 
from the test port wall, actual ft/sec (m/sec);
dlast = distance from the wall of the last 1-in. incremented wall 
effects traverse point, in. (cm);
p = the number of Method 1 of Appendix A-1 equal area traverse 
points on a diameter, (e.g., for a 16-point traverse, p = 8);
dbx = distance from the test port wall to the interior edge of the 
Method 1 of Appendix A-1 equal-area sector closest to that wall (see 
Equation 2H-4);
[nu]dremx = the measured stack gas velocity at distance 
dremx from the test port wall, actual ft/sec (m/sec);
vlast = the measured stack gas velocity at distance dlast from the 
wall, actual ft/sec (m/sec);
[nu]y = stack or duct gas point velocity value, adjusted 
for wall effects, dM1y from the test port wall, actual ft/sec (m/
sec);
[nu]dremy = the measured stack gas velocity at distance dremy from 
the test port wall, actual ft/sec (m/sec);
dby = distance from the wall perpendicular to the test 
port wall to the interior edge of the Method 1 of Appendix A-1 
equal-area sector closest to that wall (see Equation 2H-6);
vc = stack or duct gas point velocity value, adjusted for 
wall effects, at dM1 or dM1y (whichever is less) from the test port 
wall, actual ft/sec (m/sec);
vdremc = the measured stack gas velocity at a distance of 
dremx for corner test ports or at a distance of dremx if dM1 <= dm1y 
or dremy if dM1 >dM1y for non-corner test ports, actual ft/sec (m/
sec);
Cx = wall effects adjustment factor for a single traverse for all 
Method 1 of Appendix A-1 non-corner, exterior equal-area sectors 
adjacent to the test port wall and the opposing test port wall, 
dimensionless;
nx = total number of test ports where near wall measurements are 
made;
vx = stack or duct gas point velocity value, unadjusted for wall 
effects, at Method 1 of Appendix A-1 traverse point location (dM1) 
for the exterior equal-area sectors adjacent to the test port wall, 
actual ft/sec (m/sec);
j = index test ports where near wall measurements are made;
Cy = wall effects adjustment factor for a single traverse for Method 
1 of Appendix A-1 non-corner, exterior equal-area sectors adjacent 
to the walls perpendicular to the test port wall, dimensionless;
vy = stack or duct gas point velocity value, unadjusted for wall 
effects, at dM1y from the test port wall, actual ft/sec 
(m/sec);
C*c = wall effects adjustment factor for a single traverse for 
Method 1 of Appendix A-1 corner equal-area sectors that excludes the 
impact of greater intense shear in the duct corners, dimensionless;
vc = stack or duct gas point velocity value, unadjusted for wall 
effects, at dM1 for corner test ports or at dM1 or dM1y 
(whichever distance is less) from for non-corner test ports, actual 
ft/sec (m/sec);
Ccadj = an adjustment factor applied to C*c to account 
for the impact of greater intense shear in the duct corners, 
calculated in accordance with Section 12.9, dimensionless;
Cc = wall effects adjustment factor for a single traverse for Method 
1 of Appendix A-1 corner equal-area sectors including the impact of 
greater intense shear in the duct corners, dimensionless;
i = index of Method 1 of Appendix A-1 equal-area traverse points;
vi = stack or duct gas point velocity value, adjusted for 
wall effects, at Method 1 of Appendix A-1 equal-area sector i, 
actual ft/sec (m/sec);
vi = stack or duct gas point velocity value, unadjusted for wall 
effects, at Method 1 of Appendix A-1 equal-area sector i, actual ft/
sec (m/sec);
Ci = wall effects adjustment factor for Method 1 of Appendix A-1 
equal-area sector i, dimensionless;
n = total number of traverse points in the Method 1 of Appendix A-1 
traverse;
vavg = the average stack or duct gas velocity, unadjusted for wall 
effects, actual ft/sec (m/sec);
vavg = the average stack or duct gas velocity, adjusted 
for wall effects, actual ft/sec (m/sec);
WAF = the overall wall effects adjustment factor derived from vavg 
and vavg for a single traverse, dimensionless;
WAF = wall effects adjustment factor that is applied to the cross-
sectional area value used to calculate wall effects-adjusted 
volumetric flow based on reference method or CEMS velocity 
measurements, dimensionless;
Qadj = the total stack or duct gas volumetric flow rate, adjusted 
for wall effects, actual ft\3\/sec (m\3\/sec);
Qadjstd = the total stack or duct gas volumetric flow rate corrected 
to standard conditions, adjusted for wall effects, scf/sec (scm/
sec);
A = duct or stack cross-sectional area at measurement location, 
ft\2\;
Tavg = average flue gas temperature, [deg]R ([deg]K) [[deg]R = 460 + 
[deg]F ([deg]K = 273 + [deg]C)];
Tstd = standard temperature, 528 [deg]R (293 [deg]K);
Pavg = average absolute flue gas pressure, in. Hg (mm Hg);
Pstd = standard absolute pressure, 29.92 in. Hg (760 mm Hg);

    12.2 For circular stack measurement locations, calculate the 
wall effects adjusted velocities for the Method 1 of Appendix A-1 
equal area sectors adjacent to the test port wall using Equation 2H-
10:
[GRAPHIC] [TIFF OMITTED] TP25AU09.030


[[Page 42827]]


    12.3 For rectangular duct measurement locations, calculate the 
wall effects adjusted velocities for the Method 1 of Appendix A-1 
equal area sectors adjacent to the test port wall using the 
following equations.
    12.3.1 Calculate the wall effects adjusted velocity, 
vx, for each of the Method 1 of Appendix A-1 equal-area 
sectors adjacent to the test port wall using Equation 2H-11. If 
dlast > dbx, substitute the greatest one-inch interval less than dbx 
for dlast.
[GRAPHIC] [TIFF OMITTED] TP25AU09.031

    12.3.2 Calculate the wall effects adjusted 
velocity,vy, for each of the Method 1 of Appendix A-1 
equal-area sectors adjacent to the test port wall using Equation 2H-
12. If dlast > dby, substitute the greatest one-inch interval less 
than dby for dlast.
[GRAPHIC] [TIFF OMITTED] TP25AU09.032

    12.3.3 Calculate the wall effects adjusted velocity, 
vc, for each of the Method 1 of Appendix A-1 equal-area 
sectors adjacent to the test port wall using Equation 2H-13. If 
dlast > dbx or dlast > dby, substitute the greatest one-inch 
interval less than dbx or dby (whichever is less) for dlast.
[GRAPHIC] [TIFF OMITTED] TP25AU09.033

    12.4 For rectangular duct measurement locations, calculate the 
velocity correction factors for the Method 1 of Appendix A-1 equal 
area sectors adjacent to the test port wall using the following 
equations. If any of the test ports are located 12 or less in. from 
an adjacent wall (or ash layer), then reduce nx by the number of 
those ports and substitute that value for nx in the following 
equations.
    12.4.1 Calculate the wall effects correction factor, Cx, for 
Method 1 of Appendix A-1 non-corner equal-area sectors adjacent to 
the test port wall and the opposing test port wall using Equation 
2H-14.
[GRAPHIC] [TIFF OMITTED] TP25AU09.034

    12.4.2 Calculate the wall effects correction factor, Cy, for 
Method 1 of Appendix A-1 non-corner equal-area sectors adjacent to 
the walls perpendicular to the test port wall using Equation 2H-15.
[GRAPHIC] [TIFF OMITTED] TP25AU09.035

    12.4.3 Calculate the wall effects correction factor, C*c, for 
all Method 1 of Appendix A-1 corner equal-area sectors using 
Equation 2H-16.
[GRAPHIC] [TIFF OMITTED] TP25AU09.036

    12.5 For circular stacks, determine the velocity for each Method 
1 of Appendix A-1 equal-area sector, vi, adjusted for wall effects 
in the following manner:
    (a) For equal area sectors adjacent to the test port wall that 
are used for normal reference method flow testing, vi=vx, where vx 
is calculated using Equation 2H-10.
    (b) For interior equal area sectors, vi=vi.
    (c) If, in accordance with section 8.1.2, near wall measurements 
are excluded from any test ports that are used for normal reference 
method flow testing (or no test port is available for any exterior 
Method 1 of Appendix A-1 equal area sector), the wall effects 
adjusted velocities for the excluded Method 1 of Appendix A-1 equal 
area sectors is calculated as vi=v1x Cx. Calculate CX using Equation 
2H-14.
    12.6 For rectangular ducts, calculate the velocity in each 
Method 1 of Appendix A-1 equal-area sector, vi, adjusted for wall 
effects, using Equation 2H-17:

[GRAPHIC] [TIFF OMITTED] TP25AU09.037

Where:

Ci is the appropriate correction factor for the given Method 1 of 
Appendix A-1 equal-area sector:
Ci = 1 for Method 1 of Appendix A-1 interior equal-area sectors
Ci = Cx for Method 1 of Appendix A-1 non-corner, exterior equal-area 
sectors adjacent to the test port wall or the opposing test port 
wall
Ci = Cy for Method 1 of Appendix A-1 non-corner, exterior equal-area 
sectors adjacent to the walls perpendicular to the test port wall
Ci = Cc for Method 1 of Appendix A-1 corner equal-area sectors. Cc = 
C*c x Ccadj (See Section 12.9)

    12.7 Calculate the wall adjustment factor, WAF, using Equations 
2H-18 through 2H-20.
    12.7.1 Calculate the average stack or duct gas velocity that 
does not account for velocity decay near the wall (vavg using 
Equation 2H-18.
[GRAPHIC] [TIFF OMITTED] TP25AU09.041

    12.7.2 Calculate the average stack or duct gas velocity, 
adjusted for wall effects, vavg, using Equation 2H-19.
[GRAPHIC] [TIFF OMITTED] TP25AU09.038

    12.7.3 Calculate the wall effects adjustment factor, WAF, using 
Equation 2H-20.
[GRAPHIC] [TIFF OMITTED] TP25AU09.039

    12.8 Applying a Wall Effects Adjustment Factor. A calculated 
wall effects adjustment factor may be used to adjust the average 
flue gas volumetric flow obtained using Methods 2, 2F, or 2G of 
Appendix A-1 and A-1 or

[[Page 42828]]

CEMS measurements to take into account velocity decay near the wall 
of stacks or ducts using Equation 2H-21a or 2H-21b.
[GRAPHIC] [TIFF OMITTED] TP25AU09.022

[GRAPHIC] [TIFF OMITTED] TP25AU09.023

The wall effects adjustment factor, WAF, shown in Equation 2H-21a 
and 2H-21b, must be the arithmetic average of WAF values obtained 
during at least three wall effects test runs unless a stack or duct 
specific WAF default factor is calculated in accordance with Section 
8.3.2. A WAF can only be applied when calculating volumetric flows 
based on velocity data from RATAs consisting of the same number (or 
fewer) of Method 1 of Appendix A-1 traverse points used to determine 
the WAF or from a CEMS for which such a RATA has been conducted. The 
WAF must be reassessed whenever the stack or ductwork is altered 
such that the flow profile is significantly changed.
    12.9 Corner Correction. For rectangular duct measurement 
locations: A default value of Ccadj = 0.995 may be used for any duct 
to account for the more intense viscous shear in the corner regions. 
Alternatively, calculate a duct specific Ccadj using Equation 2H-22:
[GRAPHIC] [TIFF OMITTED] TP25AU09.024

Where:

Dh = hydraulic diameter, ft (m); 4 x cross-sectional 
area/perimeter
Deff = effective diameter including corner impact; 
Deff = [64/(fRe)]Dh
[egr] = average duct surface roughness, ft (m)

Calculate Deff, using the value for friction constant, 
fRe, from the Table 1, interpolating as needed. The parameter b/a is 
the duct aspect ratio, where b represents the smaller of the two 
stack or duct dimensions.

            Table 1--Friction Constants for Rectangular Ducts
------------------------------------------------------------------------
       b/a                f Re               b/a              f Re
------------------------------------------------------------------------
        0.00              96.00              0.25             72.93
        0.05              89.91              0.40             65.47
        0.10              84.68              0.50             62.19
       0.125              82.34              0.75             57.89
       0.167              78.81              1.00             56.91
------------------------------------------------------------------------

Calculate the average stack or duct surface roughness, [egr], based 
on the surface roughness values calculated for each test port 
location using the Equation 2H-23:
[GRAPHIC] [TIFF OMITTED] TP25AU09.025

Where:

V1 = velocity measured at the closest available one-inch 
interval from the wall, ft/s (m/s)
V2 = velocity measured at a distance of 12 in. (30 cm) 
from the wall, ft/s (m/s)
y1 = distance of the closest available one-inch interval 
from the wall, in. (cm)

13.0 Method Performance [Reserved]

14.0 Pollution Prevention [Reserved]

15.0 Waste Management [Reserved]

16.0 Reporting

    16.1 Field Test Reports. Field test reports shall be submitted 
to the Agency according to the applicable regulatory requirements. 
When this method is performed in conjunction with Method 2, 2F, or 
2G of Appendix A-1 and A-2 to derive a wall effects adjustment 
factor, a single consolidated field test report should be prepared. 
At a minimum, the consolidated field test report should contain (1) 
all of the general information, and data for Method 1 of Appendix A-
1 points, specified in Section 16.0 of Method 2F of Appendix A-1 
(when this method is used in conjunction with Method 2F of Appendix 
A-1) or Section 16.0 of Method 2G of Appendix A-2 (when this method 
is used in conjunction with Method 2 or 2G of Appendix A-1 and A-2) 
and (2) the additional general information, and data for Method 1 of 
Appendix A-1 points and wall effects points, specified in this 
section (some of which are included in Section 16.0 of Methods 2F 
and 2G of Appendix A-1 and A-2 and are repeated in this section to 
ensure complete reporting for wall effects testing).
    16.2 Data for each run. The following run values should also be 
included in the field test report.
    (a) Average velocity for run, accounting for wall effects, vavg.
    (b) Wall effects adjustment factor derived from a test run, WAF.
    16.3 Quality Assurance and Control. Quality assurance and 
control procedures, specifically tailored to wall effects testing, 
should be described.
    16.4 Reporting a Default Wall Effects Adjustment Factor. 
[Reserved]

17.0 References

    17.1 Impact of Viscous Shear Wall Effects on Flow Measurements 
in Rectangular Ducts, EPRI, Palo Alto, CA: 2003. 10076649.
    17.2 Norfleet, Stephen K. CTM-041 and Potential Revisions to EPA 
Reference Method 2H, 2005 EPRI CEMS Users Group Meeting, Savannah, 
Georgia, May 2005.
    17.3 Norfleet, Stephen K. Correcting Flow Measurements for Wall 
Effects in Rectangular Ducts and Stacks, 2003 EPRI CEM Users Group 
Meeting, San Diego, California, May 2003.
    17.4 White, Frank M. Fluid Mechanics, 2nd ed., McGraw-Hill, New 
York. 1986.
    17.5 EPA Flow Reference Method Testing and Analysis: Findings 
Report, U.S. EPA, Acid Rain Division, EPA/430-R-99-009a, May 1999.
    17.6 40 CFR Part 60, Appendix A-1, ``Method 1--Sample and 
Velocity Traverses for Stationary Sources.''
    17.7 40 CFR Part 60, Appendix A-1, ``Method 2--Determination of 
Stack Gas Velocity and Volumetric Flow Rate (Type S Pitot Tube).''
    17.8 40 CFR Part 60, Appendix A-1, ``Method 2F--Determination of 
Stack Gas Velocity and Volumetric Flow Rate with Three-Dimensional 
Probes.''
    17.9 40 CFR Part 60, Appendix A-2, ``Method 2G--Determination of 
Stack Gas Velocity and Volumetric Flow Rate with Two-Dimensional 
Probes.''
BILLING CODE 6560-50-P

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[[Page 42830]]


[GRAPHIC] [TIFF OMITTED] TP25AU09.027

[GRAPHIC] [TIFF OMITTED] TP25AU09.028


[[Page 42831]]


[FR Doc. E9-20395 Filed 8-24-09; 8:45 am]
BILLING CODE 6560-50-C