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National Emission Standards for
Hazardous Air Pollutants for
Engine Test Cells/Stands -
Background Information for Final
Standards
Summary of Public Comments and Responses
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EPA453/R-03-001
February 2003
National Emission Standards for
Hazardous Air Pollutants for
Engine Test Cells/Stands
Background Information for Final Standards
Summary of Public Comments and Responses
Contract No. 68-D-01-079
Work Assignment No. 1-06
Project No. 97/11
U.S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Emission Standards Division
Research Triangle Park, North Carolina 27711
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Disclaimer
This report has been reviewed by the Emission Standards Division of the Office of Air Quality Planning
and Standards, EPA, and approved for publication. Mention of trade names or commercial products is
not intended to constitute endorsement or recommendation for use.
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TABLE OF CONTENTS
Chapter 1. Summary 1-1
1.1 Summary of Changes Since Proposal 1-1
1.1.1 Applicability 1-2
1.1.2 Affected Source 1-2
1.1.3 Compliance Dates 1-3
1.1.4 Modification or Reconstruction 1-3
1.1.5 New Source MACT 1-3
1.1.6 Monitoring Requirements 1-4
1.1.7 Startup, Shutdown, and Malfunction (SSM) 1-4
1.2 Summary of Impacts of Promulgated Regulation 1-4
Chapter 2. Summary of Public Comments 2-1
2.1 Applicability 2-6
2.2 Affected Source 2-17
2.3 Existing Source MACT 2-20
2.4 New Source MACT 2-21
2.5 Reconstruction 2-25
2.6 Monitoring Requirements 2-29
2.7 Cost and Economic Assumptions and Impacts 2-33
2.8 Startup, Shutdown, and Malfunction (SSM) 2-35
2.9 Compliance Procedures 2-37
2.10 Compliance Dates 2-37
2.11 Averaging 2-38
2.12 Miscellaneous 2-41
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LIST OF TABLES
Page
Table 2-1. List of Commenters on Proposed Standards of Performance for
Engine Test Cells/Stands 2-2
Table 2-2. Individuals Providing Verbal Comments at the Public Hearing of the
Proposed NESHAP for Engine Test Cells/Stands 2-5
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Chapter 1
Summary
On May 14,2002, the U. S. Environmental Protection Agency (EPA) proposed national
emission standards for hazardous air pollutants (NESHAP) for engine test cells/stands (67 FR 34548)
under authority of Section 112 of the Clean Air Act (Act). Public comments were received from 24
sources consisting mainly of automotive, truck, and diesel engine manufacturers; airlines; aircraft and
marine engine manufacturers; various industry trade associations; and Government agencies.
All of the comments that were submitted and the responses to these comments are summarized
in this document. This summary is the basis for the revisions made to the standards between proposal
and promulgatioa
1.1 SUMMARY OF CHANGES SINCE PROPOSAL
Several changes have been made since the proposal of these standards. Major changes
include: a revised and broader definition of affected source that impacts when new source maximum
achievable control technology (MACT) is required for new and reconstructed sources; revised
emission limits for new source engine test cells/stands used to test internal combustion (1C) engines with
power ratings equal to or above 25 horsepower (hp); addition of parametric monitoring for add-on
control devices; and an exemption for reconstructed affected sources used for testing to comply with
Title n (mobile source) regulations.
Other changes have been made to clarify portions of the rule that were unclear to the
commenters and to reduce the recordkeeping and reporting burden. A summary of the major changes
is presented in the following sections.
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1.1.1 Applicability
The proposed rule applied to an owner or operator of engine test cells/stands located at major
sources of hazardous air pollutant (HAP) emissions. An engine test cell/stand was defined in the
proposed rule as any apparatus used for testing uninstalled stationary or uninstalled mobile (motive)
engines. However, the proposed rule did not include a definition of "uninstalled engine."
Changes were made to clarify that the final rule is regulating the testing of engines, not the
testing of any final product (e.g., automobile, boat, power generator, etc.). If the engine being tested in
a test cell/stand is not installed in, or an integrated part of, the final product, then the test cells/stands are
considered part of the affected source.
This new definition for "uninstalled" also clarifies the applicability of outboard motors.
Outboard motors are considered "installed" when the engine is coupled with the gear drive and
propeller. Therefore, a facility with engine testing involving outboard motors, in their vessel-installed
configuration, is not an affected source.
Changes were made to add some specific exclusions to the applicability determination. Test
cells that are operated to test or evaluate fuels (such as knock engines), transmissions, electronics, etc.,
are now excluded, as well as research and teaching activities at major source facilities that are not
engaged in the development of engines or engine test services for commercial purposes.
1.1.2 Affected Source
The proposed rule defined the affected source as any existing, new, or reconstructed engine
test cell/stand used for testing uninstalled stationary or uninstalled mobile (motive) engines that is located
at a major source of HAP emissions. The final rule includes a new definition of affected source in
accordance with the rationale in the amended General Provisions (67 FR 16588). The new definition
of an affected source is the collection of all equipment and activities associated with engine test
cells/stands used for testing uninstalled stationary or uninstalled mobile (motive) engines located at a
major source of HAP emissions.
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1.1.3 Compliance Dates
Several comments noted an inadvertent error in the proposal preamble language. There was a
discrepancy between the language in the preamble and the rule concerning the compliance date. The
proposal regulatory text was correct. The final rule clarifies the compliance date for existing sources as
three years after the effective (promulgation) date, and the compliance date for new sources as the
effective date or upon startup, whichever is later.
1.1.4 Modification or Reconstruction
Several comments were made about the diversity of engine test cells/stands and test
requirements used by the various types of engine manufacturers and industry sectors. The comments
included recommendations on how to define what types of test equipment and support equipment
comprise an actual engine test cell/stand (e.g., affected source) or reconstructed source.
Many of these recommendations have been incorporated into the final rule, which includes new
language clarifying that changes made to an existing affected source primarily for the purpose of
complying with revised engine testing requirements under 40 CFR parts 80, 86, 89,90,91, or 92 are
not considered a modification or reconstruction. Therefore, those affected sources modified to meet
requirements in those parts and subparts will not be subject to new source MACT.
Changes were also made to the final rule to include language that excludes passive
measurement and control instrumentation and electronics from the reconstruction evaluation. The final
rule preamble also clarifies that movement or relocation of portable (wheeled) test stands within a
facility is not considered reconstruction.
1.1.5 New Source MACT
Several comments involved the stringency of the emission limits associated with new source
MACT. The new source emission limits have been changed in the final rule to 96 percent reduction for
carbon monoxide (CO) or total hydrocarbons (THC) or outlet concentrations of 20 ppmvd CO or
THC based on the updated test data, additional test reports, and estimates reflecting the most prevalent
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engine test setups and conditions across all engine testing sectors involving engines greater than or equal
to 25 hp.
1.1.6 Monitoring Requirements
Based on comments received, the monitoring requirements have been changed in the final rule
to allow parameter (temperature) monitoring for thermal oxidizers. In the case of a regenerative thermal
oxidizer (RTO), the temperature is monitored during the initial performance test After the RTO meets
the performance test requirements, the operating temperature is continuously monitored to demonstrate
compliance with the applicable new source emission limit
1.1.7 Startup, Shutdown, and Malfunction (SSM)
The proposed rule specifically required affected sources to comply with the applicable emission
limitation at all times, including startup, shutdown, and malfunction (SSM). Because the SSM
provisions apply to the process as well as the control equipment, the impact of the engine test
NESHAP to minimize HAP emissions would be significantly reduced by adopting the SSM provisions.
Based on the comments, the final rule includes SSM provisions for any control equipment and
monitoring equipment related to engine test cells/stands emissions. The new language references the
General Provisions for SSM procedures related to control equipment and associated monitoring
equipment.
1.2 SUMMARY OF IMPACTS OF PROMULGATED REGULATION
The final standards will reduce nationwide emissions of hazardous air pollutants (HAP) from
engine test cells/stands by 59.5 megagrams per year (Mg/yr) (65.5 tons per year (tpy)) from projected
new or reconstructed sources. No significant adverse secondary air, water, or solid waste impacts are
anticipated from the promulgation of these standards.
The implementation of this rule is expected to result in an overall annual cost of $3.2 million.
The economic impact analysis shows that the economic impacts from these final standards are
insignificant
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Chapter 2
Summary of Public Comments
A total of 24 letters commenting on the proposed standards and supporting technical
memoranda for the proposed standards were received. Comments from the public hearing on the
proposed standards were recorded, and a transcript of the hearing was placed in the project docket.
A list of commenters, their affiliations, and the EPA docket number assigned to their correspondence
are given in Tables 2-1 and 2-2.
For the purpose of orderly presentation, the comments have been categorized under the
following topics:
1. Applicability;
2. Affected source;
3. Existing source MACT;
4. New source MACT;
5. Reconstruction;
6. Monitoring requirements;
7. Cost and economic assumptions and impacts;
8. Startup, shutdown, and malfunction (SSM);
9. Compliance procedures;
10. Compliance dates;
11. Averaging; and
12. Miscellaneous.
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The comments, the issues they address, and EPA's responses are discussed in the following
sections of this chapter.
Table 2-1. List of Commenters on Proposed Standards of Performance for
Engine Test Cells/Stands
Docket Item No.1
Commenter/Affiliation
IV-D-01
Ms. Janice Bardi
Administrative Assistant
ASTM International
100 Barr Harbor Drive, P.O. Box C700
W. Conshohocken, PA 19428-2959
IV-D-02
Dr. Robin M. Ridgway
Environmental Regulatory Consultant
Purdue University REM/Utilities
1662 Civil Engineering Building B173
West Lafayette, IN 47907
IV-D-03
Mr. Joseph L. Suchecki
Director, Public Affairs
Engine Manufacturers Association
Two North LaSalle Street, Suite 2200
Chicago, IL 60602
IV-D-04
Mr. Keith W. Skaggs
Anteon Corporation
3211 Jermantown Road, Suite 700
Fairfax, VA 22030
IV-D-05
Mr. Scott F. Belcher
Managing Director
Environmental Affairs and Assistant General Counsel
Air Transport Association of America, Inc.
1301 Pennsylvania Ave., NW, Suite 1100
Washington, DC 20004-1707
IV-D-06
Mr. David C. Foerter
Deputy Director
Institute of Clean Air Companies, Inc.
1660 L Street, NW, Suite 1100
Washington, DC 20036
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Table 2-1. (Continued)
Docket Item No."
IV-D-07
IV-D-08
IV-D-09
IV-D-10
IV-D-11
IV-D-12
Commenter/ Affiliation
Mr. David C. Footer
Deputy Director
Institute of Clean Air Companies, Inc.
1660 L Street, NW, Suite 1 100
Washington, DC 20036
Mr. Donald R. Schregardus
Deputy Assistant Secretary for Installations and Environment
Office of the Assistant Secretary
Department of the Navy
1000 Navy Pentagon
Washington, DC 20350-1000
Mr. Lawrence E. Keller
Manager, Corporate Environmental Compliance
Polaris Industries, Inc.
805 Seminole Avenue
Osceola, WI 54020
Mr. Nicholas Gertler
Counsel, Latham & Watkins
555 11th Street, NW, Suite 100
Washington, DC 20004
On behalf of:
International Truck and Engine Corporation
455 N. Cityfiont Plaza Drive
Chicago, IL 6061 1
Ms. Thelma R. Norman
Senior Engineer
American Airlines
MD 508, P.O. Box 582809
Tulsa, OK 74 159-2809
Mr. Robert T. Marlow
Vice President, Government Division
Aerospace Industries Association
1250 Eye Street, NW
Washington, DC 20005-3924
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Table 2-1. (Continued)
Docket Item No."
IV-D-13
IV-D-14
IV-D-15
IV-D-16
IV-D-17
IV-D-18
IV-D-19
Commenter/Afiiliation
Ms. Karen Keyob
Associate Chief Engineer, Environmental
Honda of America Mfg., Inc.
24000 Honda Parkway
Marysville, OH 43040
Ms. Olga M. Dominguez
Director, Environmental Management Division
National Aeronautics and Space Administration Headquarters
Washington, DC 20546-0001
Mr. Gregory J. Dana
Vice President, Environmental Affairs
Alliance of Automobile Manufacturers
1401 H Street, NW, Suite 900
Washington, DC 20005
Mr. James W. Sumner
Manager, Group Environmental Programs
GE Aircraft Engines
One Neumann Way, Mail Drop T165
Cincinnati, OH 45215-6301
Ms. Lisa S. Beal
Director, Environmental Affairs
Interstate Natural Gas Association of America
10 G Street NE, Suite 700
Washington, D.C. 20002
Mr. Ted Steichen
Senior Regulatory Analyst
American Petroleum Institute
1 220 L Street, NW
Washington, DC 20005^070
Mr. John McKnight
Director, Environmental and Safety Compliance
National Marine Manufacturers Association
200 E. Randolph Dr., Suite 5100
Chicago, IL 60601
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Table 2-1. (Continued)
Docket Item No.8
•IV-D-20
IV-D-21
IV-D-22
IV-D-23
IV-D-24
Commenter/Affiliation
Mr. Joseph L. Suchecki
Director, Public Affairs
Engine Manufacturers Association
Two North LaSalle Street, Suite 2200
Chicago, IL 60602
Mr. Andy Lawrence
Director, Office of Environmental Policy and Guidance
Department of Energy
Washington, DC 20585
Mr. David M. Boyd
Corporate Environmental Manager
Briggs & Stratton Corporation
12301 W. Wirth Street
Wauwatosa,WI 53222-2110
Mr. Myron Hafele
Supervisor - EHS Air Group
Kohler Company
Kohler.WI 53044
Mr. Robert W. Stachowicz
Senior Development Engineer
Waukesha Engine, Dresser, Inc.
1000 West St. Paul Avenue
Waukesha, WI 53188-4999
' The docket number for the engine test cells/stands NESHAP is A-98-29.
Table 2-2. Individuals Providing Verbal Comments at the Public Hearing of the
Proposed NESHAP for Engine Test Cells/Stands
Docket Item No."
IV-F-01
Commenter/Affiliation
Mr. Joseph Suchecki
Director of Public Affairs
Engine Manufacturers Association
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IV-F-02
Mr. Craig Dousharm
Senior Environmental Engineer
Mercury Marine (Division of Brunswick Corporation)
Fond du Lac, Wisconsin
On behalf of:
National Marine Manufacturers Association
IV-F-03
Ms. Mary Snow-Cooper
Senior Regulatory Planning Specialist
DaimlerChrysler Corporation
On behalf of:
Alliance of Automobile Manufacturers
a The docket number for the engine test cells/stands NESHAP is A-98-29.
2.1 APPLICABILITY
2.1.1 Comment: Five commenters (TV-D-03, IV-D-08, IV-D-19, IV-D-24, and IV-F-02)
requested clarification of "uninstalled engine" versus "installed engine" testing in regards to determining
applicability of the final rule.
Response: The affected source is defined as the collection of all equipment and activities
associated with engine test cells/stands used for testing uninstalled stationary or uninstalled mobile
(motive) engines located at a major source of HAP emissions. We are regulating the testing of engines,
not the testing of any final product (e.g., automobile, boat, power generator, etc.). If the engine being
tested in a test cell/stand is not installed in, or an integrated part of, the final product, then the test cell(s)
or test stand(s) would be considered part of the affected source.
2.1.2 Comment: Three commenters (TV-D-08, IV-D-19, and IV-F-02) made comments
concerning the applicability of the rule to marine engines. Commenter IV-D-08 stated that outboard
motors operated while detached from a boat should not be considered uninstalled, since "the engine
remains coupled to lower unit gear drive and propeller without modification to its vessel-installed
configuration." The commenter recommended that EPA either define "uninstalled" or clarify in the
preamble that the rule does not affect outboard motors when operated while detached from a boat.
Two commenters (TV-D-19 and IV-F-02) stated that recreational marine engines are tested as a
complete regulated package with emission controls installed. The rule would therefore require emission
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controls on test cells used to test engines that already have emission controls. These two commenters
saw no difference between a regulated installed engine (e.g., in an automobile) and a regulated emission
controlled uninstalled engine being tested by recreational marine engine manufacturers.
Response: We agree with the commenters and consider outboard motors to be installed engines
when the engine is coupled with the gear drive and propeller. Therefore, because the rule applies only
to uninstalled engines, outboard motors (in their vessel-installed configuration) are not affected sources.
While it is true that most recreational marine engines have emission controls already installed,
the same is true for virtually all engines sold. It is important to note, however, that the emission limits in
the rulemaking apply to the engine test cells/stands, and mat the engines that are tested do not always
comply with their applicable mobile source requirements. For example, engines are sometimes tested
without after-treatment, or the electronic controls may not be optimized for lowest emissions. Another
important fact to note is that engines have different emission standards to meet depending on the end
use. For instance, mobile-source emission standards for automobile engines are different from those for
recreational marine engines. This means that emissions from these engines are regulated (e.g., reduced)
to very different levels. Thus, the fact that engines may be tested with their emission controls installed
does not guarantee that HAP reductions equivalent to the emission limit required in this rulemaking are
taking place.
2.1.3 Comment: Several commenters (IV-D-03, IV-D-09, IV-D-10, IV-D-13, IV-D-15,
IV-D-16, IV-D-19, IV-D-23, IV-D-24, IV-F-02, and IV-F-03) stated that engine testing required by
other regulations (e.g., mobile source rules) should be exempt from this NESHAP. Six of the
commenters (IV-D-03, IV-D-09, IV-D-15, IV-D-16, IV-D-23, and IV-D-24) stated that the final
rule should not require further treatment when the engines are designed and constructed to be compliant
with mobile source (Tide H) standards. Commenter IV-D-09 stated that EPA should exempt test cells
used to test uninstalled engines pursuant to applicable mobile source emission regulations. The
"uninstalled engine" proposal, according to one commenter, should be extended to products covered
by vehicle-based emission standards for which testing of fully equipped, uninstalled engines is
nevertheless allowed for compliance demonstration purposes, e.g., ATVs. Commenter IV-D-23 stated
that it is unreasonable to require the locations that test engines meeting the EPA or California ARC non-
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road emission standards to have additional oxidation control and monitoring systems. Commenter
IV-D-13 recommended an exemption for engine test cells/stands in which 90 percent or more of the
engines being tested meet the mobile source emission standards. Commenter IV-D-10 recommended
that EPA exempt on-road diesel engine test cells from the control requirements of the proposed rule
because EPA already regulates essentially the same emissions units to the full extent of technological
feasibility under the Agency's mobile source regulations. Commenter IV-D-03 requested that the
precedent used to exempt installed engine testing from the regulation should be extended to the quality
and/or final testing of engines that must comply with Federal or State emissions standards. Commenter
FV-D-24 stated that there is no difference between installed and uninstalled engines in the small engine
classificatioa Other commenters from the marine industry similarly stated that much of the engine
testing conducted on marine engines is required by other EPA regulations for certification of compliance
with mobile source emission limits. Emissions from the testing of such engines should not be subject to
additional controls as proposed.
Commenter FV-D-15 recommended that the rule should not require further emission treatment
when the engines being tested are constructed to be compliant with mobile source standards or when
the engines are powered exclusively by natural gas. The commenter noted that:
In the preamble of EPA's March 2001 final rule on "Control of Emissions of
Hazardous Air Pollutants from Mobile Sources" (66 Fed. Reg. 17230), EPA states
that its analysis shows that existing and proposed emission control programs for mobile
sources are expected to yield significant reductions of mobile source air toxics. EPA
goes on to state that it is not setting additional vehicle-based air toxics controls because
the technology-forcing Tier 2 light duty vehicle standards and the new standards for
heavy duty engines and vehicles "represent the greatest degree of toxics control
achievable at this time considering existing standards, the availability and cost of
technology, and noise, energy and safety factors and lead time."
The commenter suggested that an owner or operator might be encouraged to accept a requirement that
it not operate any engine in a new or reconstructed test cell/stand that is not served by a thermal
oxidizer or similar control device unless the engine has catalytic or other controls designed to achieve
Title II standards.
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Response: This NESHAP is applicable to engine test cells/stands and not engines. Thus, even
though certification testing is conducted in order to determine compliance of some engines with EPA
regulations under Title 0 of the Act and to demonstrate that a given engine meets the established mobile
source emission standard, such testing is not applicable to engine test cells/stands per se. Further,
although some engines are being tested to demonstrate compliance with a mobile source emission limit,
this does not necessarily mean that the facility conducting such testing is not a major source of HAP
emissions and should thus be exempt from having to comply with this NESHAP.
New engine test cells/stands used for certification testing are virtually identical to other
production test cells/stands and emit the same HAP. In addition, not all test cells/stands are configured
to specifically meet the mobile source (Title II) requirements and the mobile source certification testing
is often conducted under varying and different testing conditions. Further, the engines tested for
certification purposes are required to meet different standards for emissions reduction, which are not
equally stringent (i.e. off-road engines vs. on-road engines). The compliance of engines with a mobile
source regulation aimed at reducing criteria pollutant emissions does not necessarily mean that the
facility in question is not a major source of HAP emissions. A facility may test several hundred engines
(which produce HAP emissions) per day, and those emissions combined with other emission sources
located at the major source, provide the potential for the facility to emit significant levels of HAP.
Therefore, any new engine test cells/stands used for testing internal combustion engines greater than or
equal to 25 hp are covered by the final rule.
One of the commenters also mentioned a "precedent used to exempt installed engines" in
support of their recommendation to exclude the testing of regulated and uninstalled engines from this
regulation. No such precedent exists, and we have not made any determination that exempts the testing
of installed engines from this regulation. The testing of installed engines is not covered by this regulation
simply because it is not considered part of the "engine test cells/stands" source category that we are
required to regulate under the statute.
2.1.4 Comment: Four commenters (IV-D-08, IV-D-09, IV-D-13, and IV-D-14) urged
EPA to add an exemption to the control requirements for new/reconstructed engine test cells/stands
used for testing engines with very low level of emissions due to their size or method of operation.
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Commenter IV-D-08 stated that the rule should include a low-use exemption to prevent insignificant
engine testing operations that occur on major HAP source facilities from being subject to the regulation.
This commenter recommended that the EPA add the following exemption in section 63.9290:
A new or reconstructed uninstalled 1C engine test stand which is not otherwise exempt
does not have to meet the requirements of this subpart and subpart A of this part if the
facility-wide fuel consumption of all new or reconstructed uninstalled 1C engines test
stands is less than 10,000 gallons per year. Facilities shall maintain fuel consumption
records to demonstrate that they meet the criteria but shall not be subject to any other
provisions of this subpart.
Commenter FV-D-09 suggested a threshold based on actual emissions of greater than 5 tpy from the
potentially affected engine test cell/stand. Commenter IV-D-14 stated that since their annual HAP
emissions from all engine testing is estimated to be 0.5 tons of combined HAP per year, EPA should
consider including a low-use exemption or de minimis use threshold based on hours of operation or
amount of fuel consumed.
Response: The HAP emission levels from different types of engines are very different and do
not necessarily correlate with the fuel consumption of the engine. In order to set a low-use exemption
based on fuel consumption, one would have to establish a correlation between HAP emissions and
volume of fuel used. That type of correlation is not unique and varies greatly depending on engine type,
size, and fuel type. The commenter did not provide any information that showed what 10,000 gallons
of fuel is equivalent to in terms of HAP emissions. Likewise, an exemption based on hours of operation
is not appropriate if one follows the same rationale described above. Thus, for these reasons we are
not adding a low-use exemption to the final rule. We believe that the definition of major source already
provides a threshold that separates facilities that emit significant amounts of HAP from those that do
not.
2.1.5 Comment: Four commenters (IV-D-03, FV-D-22, IV-D-23, and IV-F-01) supported
an exemption for small engine testing but requested that the cutoff point should be based on cylinder
displacement and not horsepower (hp); they specifically requested that the 25 hp limit be replaced with
a 1.0-hter displacement. Commenter FV-D-22 encouraged EPA to redefine the subcategory from test
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cells/stands for testing internal combustion engines from a rated power of less than 25 hp to test
cells/stands for testing internal combustion engines with a displacement equal to or less than 1.0 liter and
a rated horsepower of less than 40 hp. All four commenters noted that the EPA currently allows the
use of the 1.0-liter cutoff point under the "Small SI Rule" (40 CFR 90.1) and has included a 1.0-liter
cutoff point in the "Large SI Rule" proposed in 2001 (FR 66:51097-51272 October 5,2001).
Response: We evaluated existing and proposed mobile source and engine regulations. Existing
EPA and California regulations do not support a definitive engine size cutoff. These regulations include
criteria in terms of horsepower and engine displacement, but 25 hp does not always equate to 1.0 liters
of engine displacement since it can vary depending on other individual engine characteristics. We found
that, in most cases, an internal combustion engine with 1.0 liter of engine displacement correlates to
approximately 50 hp. As was explained in the proposal preamble, one of the main distinctions we were
trying to make was differentiating between cells/stands used for testing small engines, such as those
used in lawn and garden applications, and the larger ones. The 25 hp cutoff is a better criterion for
such engine test cells/stands and applications.
2.1.6 Comment: Two commenters (TV-D-03 and FV-F-01) noted that other than exempting
small engines, the proposed rule inappropriately applies the same controls to all types and sizes of
engines, thus factors such as test facility location, and not environmental protection needs, can trigger an
unwarranted burden on some manufacturers. The commenters recommended that the rule and
proposed controls consider HAP emissions levels and review the need for controls for engine
subcategories.
Response: Section 112 of the Clean Air Act applies to all major sources of HAP emissions.
Unless otherwise mentioned in the final rule, any major source facility with engine test cells/stands must
comply with the NESHAP requirements.
2.1.7 Comment: Two commenters (TV-D-24 and FV-F-01) were concerned that an engine
test cell source should not be defined as major by the traditional potential to emit. Both commenters
were concerned that using potential-to-emit criteria overstates HAP emissions from test cells/stands
because test cells/stands are not run on a continuous basis.
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Commenter FV-D-24 noted that these criteria do not apply because most facilities have more
test cells than are normally used because any given cell may be out of use due to instrumentation or
hardware maintenance, calibration, or failure. Commenter FV-F-01 added that test cells are generally
oversized to allow the testing of the largest engine in production or development, but the largest engines
are generally tested in only very small numbers compared to smaller engines in the manufacturer's line.
Both commenters offered recommendations for determination of major source status.
Commenter FV-D-24 recommended that EPA devise and adopt a more realistic method of determining
potential to emit for engine test cell facilities in order to determine whether they should be classified as a
major source for regulation purposes. The commenter had two suggestions: (1) calculate the facility's
potential to emit based on a multiple of the highest total horsepower tested at the facility in any single
year over the last five years, or (2) calculate the facility's potential to emit based on a multiple of the
highest total fuel consumed by the facility for all testing purposes in any single year over the last 5 years.
Commenter IV-F-01 recommended using fuel usage, horsepower tested, or other reliable indicators to
determine major source status.
Response: The commenters did not consider HAP emissions from other processes and
emission points have to be taken into account when making a major source determination. As part of
the MACT determination, we are required to consider a facility's potential to emit, which takes into
consideration all emissions from all emission sources (e.g., engine testing, painting, fuel storage).
Accordingly, we evaluated each facility based on the information and process/emissions data submitted
in the individual facility information collection request (ICR) responses. Further, as part of the MACT
database follow-up activities prior to the MACT floor determination, we also contacted several
facilities in order to verify major source status.
2.1.8 Comment: Two commenters (TV-D-13 and IV-D-15) requested an exemption for
natural gas-fired engines. Both commenters urged EPA to exempt the control requirements for
new/reconstructed engine test cells/stands used for testing internal combustion engines of 25 hp or more
that are powered exclusively by natural gas.
Response: We considered different fuel types when we were developing the MACT floor
emissions limits. As stated earlier, the HAP emission levels from different types of engines can be very
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different and do not necessarily correlate with the fuel consumption of the engine. We found that test
cells/stands may be used to test different types and sizes of engines, as well as engines using different
fuels. We did not see any differences with the actual engine test cells/stands configuration. Also, HAPs
are still emitted from these different types of engines, and the types of HAP emitted are similar as well.
2.1.9 Comment: One commenter (TV-D-21) requested EPA consider a de minimis level of
CO and THC emissions below which emission controls would not be required, regardless of the rated
horsepower. The commenter also stated that the proposed new source MACT applied to engine test
cells/stands tested intermittently or only for limited periods of time may not be economically feasible.
Response: The outlet concentration limits for CO and THC serve as the minimum applicable
limits for the affected sources. If the outlet concentration is below the applicable emission limit, no
controls are required to demonstrate compliance. The commenter's suggested de minimis cutoff levels
are inconsistent with the Act's prescribed method for determining the MACT floor.
With regards to the commenter's statement concerning economic feasibility of applying new
source MACT to test cells/stands that are operated intermittently, we agree that any type of add-on
control device will be more expensive (in terms of cost effectiveness) if it is not operated on a
continuous basis. However, economic feasibility is not a consideration in the determination of new
source MACT, and the Clean Air Act clearly states that sources subject to new source MACT are to
be controlled to the same level as the best controlled similar source.
2.1.10 Comment: Several commenters (TV-D-03, IV-D-10, IV-D-17, IV-D-24, and
IV-F-03) requested additional subcategones for differing fuel types. Commenter IV-D-10 stated that
the proposed MACT floor for new test cells is not applicable to the testing of diesel engines because
the best controlled sources on which the floor is based are not similar to diesel test cells within the
meaning of § 112(d)(3). Two commenters (TV-D-03 and IV-D-24) stated that the same types of
controls are not appropriate for diesel and natural gas engines because they have different
characteristics. Commenter FV-D-03 specifically included the fact that diesel and natural gas-fired
engines have lower HAP emission factors. Commenter IV-D-17 stated:
EPA wrongly relied exclusively on data from gasoline-fueled engines as the basis for the
proposed standard and has failed to reconcile this data with more pertinent emissions
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data available to the Agency for natural gas-fired reciprocating internal combustion
engines, which suggests a separate subcategory is warranted for engine test cells testing
natural gas-fired reciprocating internal combustion engines.
Three commenters (TV-D-15, IV-D-16, and FV-F-01) noted that the emission limits are based on
gasoline engines, which are not representative of all engine types.
Response: We disagree with the commenters, in that, all types of internal combustion engine
testing are very similar in many aspects, including the fuel combustion process and the types of HAP
emitted. In determining the MACT, EPA derived information from the MACT database, which
included engine test cells stands used for testing gasoline, diesel engines and natural gas-fired
reciprocating internal combustion engines. According to the MACT database, the types of HAP
emitted from these engines are very similar but the relative levels of pollutants emitted can vary
significantly. For example, natural gas engines emit comparatively lower levels of some HAP than
gasoline or diesel engines; however, the natural gas engines typically emit higher levels of aldehyes. The
amount of HAP emitted will be determined by the actual number, size, and types of engines being
tested by the facility as a whole, and not by individual engines or test cells/stands. Therefore, the
information and data provided by the commenters do not justify a subcategorization scheme based on
the type of fuel being burned.
2.1.11 Comment: Two commenters (TV-D-10 and FV-F-03) noted that the floor control
requirements will cause environmental issues. Commenter FV-D-10 stated that application of the
MACT floor control requirements to the de minimis emissions from new on-road diesel engine test cells
would likely result in net environmental harms that warrant the exemption of on-road diesel engine
testing.
Response: We are aware of the potential emissions that can result from add-on control
technologies and have taken those potential emissions into account in our MACT floor determination
and the associated impact analysis. The secondary air emissions were estimated/calculated as part of
the control costs estimate in sizing the control equipment for new affected sources. Accordingly, we
are not exempting on-road diesel engine testing.
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2.1.12 Comment: Three commenters (TV-D-03, IV-D-24, and IV-F-03) stated that
research and development (R&D) facilities should not be subject to the final rule in light of
Section 112(c)(7) of the Act.
Response: The language in Section 112(c)(7) directs us to establish a separate category to
assure the equitable treatment of research facilities. Engine test cells/stands used for the purposes of
R&D are very similar, if not identical, to engine test cells/stands operated for other uses. Additionally,
the HAP species emitted by R&D test cells/stands are identical to the emissions from other test
cells/stands.
In follow-up discussions with industry representatives (see docket items IV-E-01 through
FV-E-05), we obtained more information about this issue. We learned that the option of exempting
research facilities was not viewed as favorably by industry since many companies conduct R&D and
production activities in the same facility. This and other information considered led us to conclude that
in this particular source category, it is not possible to adequately define R&D testing and distinguish it
from other types of testing.
There are, however, a few special cases related to research and/or development testing where
it may be appropriate and necessary to exempt certain types of research testing. One example, engine
test cells/stands located at universities or other teaching institutions, may be reasonably excluded from
this source category since they are not engaged in the development of engines or engine test services for
commercial purposes.
2.1.13 Comment: One commenter (TV-D-02) stated that education and teaching activities
are specifically exempted in title v rules. The commenter further stated that universities with aviation
programs use engine test stands for education purposes and they should be specifically exempted from
MACT rules.
Response: As discussed under 2.1.12, we agree that education and teaching activities involving
engine test cells/stands are not part of the source category to be regulated. Therefore, we have added
language to the final rule preamble that describes research and teaching activities at major source
facilities not intended to be covered by the engine test cells/stands NESHAP requirements.
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2.1.14 Comment: Two commenters (IV-D-03 and IV-F-03) asked if performance testing
could be exempted from the emission limit requirements.
Response: Because performance testing is part of the normal testing done at many facilities, it is
considered part of the source category and was included as part of the MACT floor determination.
Therefore, performance testing conducted in engine test cells/stands is covered by the final rule.
2.1.15 Comment: Two commenters (IV-D-15 and FV-D-16) recommended that when a
minor HAP facility becomes major, the new engine test cell/stand standard should apply only to new or
reconstructed affected sources installed after the facility becomes major. The commenters
recommended that EPA incorporate the statutory concept of applicability into the regulatory definition
and make it clear that engine test cells/stands will be subject to the new source MACT only if
construction commenced after the standards were applicable to the cell/stand.
Response: Section 63.6(c)(5) of the General Provisions states that after the effective date (i.e.,
the date the rule is promulgated), the owner or operator of an unaffected existing area source that
increases its HAP emissions such that the source becomes a major source shall comply by the date
specified in the standard for existing sources. If no such compliance date is specified in the final rule,
the source can have a period of time to comply that is equivalent to that specified for other existing
sources. However, if the existing area source becomes a major source by the addition of a new
affected source or by reconstructing, the new affected (or reconstructed) source must comply with new
source MACT immediately upon startup.
In summary, if an area source facility increases its emissions and becomes a major source after
the compliance date, the affected source at that facility will have 3 years to comply with the existing
source MACT limits (e.g., no control) and the other final rule requirements. However, if the engine
test cells/stands at theexisting area source becomes a major source by reconstructing, the reconstructed
affected source is subject to new source MACT emission limits and must comply immediately upon
startup.
2.1.16 Comment: One commenter (TV-D-16) recommended that EPA should explicitly note
that testing of engines in test cells is within the scope of the rule, even if incidentally produced power is
utilized. The preamble to the final rule should clearly state that the only applicable source category for
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engine test cells that may have incidental other uses (such as putting energy produced to productive use)
is the Engine Test Facility category.
Response: We agree with the commenter and have added language to the final rule preamble to
clarify this issue.
2.1.17 Comment: One commenter from the petroleum refinery industry (IV-D-18) stated
that the proposed engine test cells/stands standard does not apply to petroleum refinery industry
sources and requested that EPA state this explicitly in the final rulemaking. Because knock engines and
other devices used for testing fuels and lubricants at refineries do not test the engine per se, but instead
test the fuels and lubricants for product quality and development purposes, these engines are not
covered by the language of proposed §63.9285(a).
Response: We agree with the commenter that the type of testing described is not part of the
affected source. Test cells that are operated to test or evaluate fuels (such as knock engines),
transmissions, electronics, etc. are not part of the source category and are not subject to the engine test
cells/stands NESHAP requirements.
2.2 AFFECTED SOURCE
2.2.1 Comment: Three commenters (IV-D-15, IV-D-16, and FV-F-03) requested that we
reconsider the issue of regulating test facilities versus individual test cells/stands. Two commenters
(TV-D-15 and IV-D-16) stated that the definition in the proposed rule of "affected source" must be
revised to include all engine test cells/stands located at a major source. Commenter IV-D-16 further
explained that the proposed rule contains no explanation for or acknowledgment of this fundamental
change from all test cells/stands at a facility to each individual test cell or stand. Typically, test
cells/stands are grouped within a common building, often sharing common manifolds. The implication of
the proposed definition is most significant with respect to the meaning of "reconstruction" of an
"affected source." Under the proposal, the addition of a single test cell within an existing test cell bank
would trigger new source requirements.
Response: Even though the name of the source category has changed, we are regulating
exactly the same industry sectors and sources of HAP emissions. As part of the background
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information gathering and regulatory development activities associated with the proposed rule, we
collected information on individual test cells/stands and overall engine test facilities. We found some
facilities that engage in testing engines have different numbers of test cells and test various engines for
very different purposes. We also found that many facilities control only some of their engine test
cells/stands and some facilities control all of their engine test cells/stands. When evaluating the level of
HAP control associated with a facility that controls only some of their engine test cells/stands, it is
difficult to determine this value because the resulting HAP emissions are dependent on several variables,
such as engine size, fuel type, test cycles, and type of test being conducted.
Since the data available could not support that type of analysis (e.g., facility-wide), we decided
to use individual test cells/stands as the basis for determining the MACT floor. Although there are
several cases in which multiple engine test cells/stands are controlled by a common control device, each
test cell/stand was assigned a capture/control efficiency value in the MACT database and was then
used as part of the MACT floor determination.
2.2.2 Comment: One commenter (TV-D-08) recommended that the EPA define the affected
source to include the collection of all test stands and ancillary components at the facility except for
emission controls and fuel distribution equipment. The commenter specifically stated that movement or
relocation of portable test stands within a facility should not be considered reconstruction. This
commenter noted that EPA has defined the affected source to include the collection of similar processes
and their ancillary equipment in many NESHAP in order to prevent the definition of reconstruction from
applying prematurely.
Response: We have revised and adopted a broader definition of affected source consistent
with the rationale in the amended General Provisions for National Emission Standards for Hazardous
Air Pollutants, 67 FR 16582 (April 5,2002) (General Provisions): "A broader definition of affected
source permits emission requirements to apply to a larger group of processes, activities and equipment,
and may thereby facilitate more innovative and economically efficient control strategies" (67 FR
16588). The affected source is now defined as the collection of all equipment and activities associated
with engine test cells/stands used for testing uninstalled stationary or uninstalled mobile (motive) engines
located at a major source of HAP emissions. As explained in 2.2.1, we evaluated MACT on both a
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facility-wide collection of all engine test cells/stands basis and on an individual engine test cell/stand
basis. We agree with the commenter that movement or relocation of portable test stands within a
facility should not be considered reconstruction.
2.2.3 Comment: Fourcommenters(TV-D-13, IV-D-15, FV-D-16, andIV-F-03)
recommended that we evaluate logical groupings of engine test cells as the affected source and believe
that the database shows that control devices exist specifically only for groups of four test cells. Two
commenters (TV-D-13 and IV-D-16) state that the "best controlled similar source" is a group of engine
test cells/stands, not a single engine test cell/stand.
Response: We evaluated several groupings of engine test cells/stands based on the information
in the MACT database. Different facilities had different ways of grouping their test cells/stands based
on production and existing regulatory requirements. There are also facilities with a single engine test cell
and some with several uncontrolled test cells and only one (or a few) controlled test cells. Because of
the variability within the facilities comprising the MACT database, we decided that individual test
cells/stands is the best approach for the MACT floor determination for the engine test cells/stands
source category.
2.2.4 Comment: One commenter (TV-F-01) requested a clarification of the regulated source.
Specifically, the commenter wanted to know what needs to be controlled if a single test cell is
reconstructed or new.
Response: See response to 2.2.2 for the revised definition of affected source in the final rule. If
a single test cell is added or reconstructed at an existing major source facility with several (e.g., more
than two) test cells, it is unlikely that new source MACT would be triggered. The amended General
Provisions defines reconstruction in terms of a "comparable new source." If the existing facility has
multiple test cells/stands as part of its affected source, it is unlikely that a single test cell would cost
more than 50 percent of the fixed capital cost that would be required to construct a comparable new
source. The owner or operator of a new engine test facility with an affected source that tests any
engine with a rated power greater than or equal to 25 hp has to comply with the new source MACT
emission limits and all other compliance requirements. (See 2.5.2 for related comments.)
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2.2.5 Comment: One commenter (IV-D-04) recommended rewording so that the rule
applies to facilities that"... own, operate or intend to construct... located at a major source or
potential major source...."
Response: We believe the language in the proposed rule is clear and consistent with that in
other NESHAP as well as the General Provisions.
2.2.6 Comment: Three commenters (TV-D-13, IV-D-15, and IV-D-16) recommended that
the term "engine test cell/stand" should be defined to clarify that a rotary test firing operation that holds
numerous engines is only a single engine test cell/stand.
Response: We collected data from several engine test facilities with the type of "carousel
testing" setup described by the commenters. We also conducted a site visit to one of these facilities that
had approximately 25 engines mounted and tested on each of two different hot test rotating carousels
(see site visit trip report in docket A-98-29, item n-B-3). We considered such configurations to be a
single test stand for purposes of the engine test cells/stands NESHAP and MACT floor development.
However, as discussed under comment 2.2.2, the revised definition of affected source provides for the
"collection of all equipment involved in engine testing," which relieves the necessity for specific language
regarding carousel testing setups.
2.2.7 Comment: Two commenters (TV-D-15 and IV-D-16) recommended that, to avoid
confusion, EPA should eliminate the term "stand" from the definition of an engine test cell.
Response: We realize that some of these terms are used differently by the various industry
sectors. However, "test stand" properly describes the test apparatus or test device used at some
engine test facilities.
2.2.8 Comment: One commenter (TV-D-19) asked if testing of engines with end-of-pipe
controls already installed as part of the test cell/stand configuration would be considered an affected
source.
Response: Yes. The affected source includes all test cell(s) and test stand(s) used to test
uninstalled engines, with or without add-on controls, including any incorporated end-of-pipe controls.
2.3 EXISTING SOURCE MACT
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2.3.1 Comment: Ninecommenters(TV-D-03,IV-D-05,IV-D-15,IV-D-16,rV-D-19,
IV-D-22, IV-D-23, FV-D-24, and IV-F-03) supported the determination that the MACT floor for
existing test cells/stands is "no control." Three commenters (TV-D-05, IV-D-11, and IV-D-12)
concurred in EPA's determination that the appropriate MACT floor is "no reduction in HAP emissions"
for Combustion Turbine Cells.
Response: No response needed.
2.3.2 Comment: Two commenters (TV-D-15 and IV-F-03) supported EPA's conclusion
that above-the-floor controls in existing facilities are not appropriate. Three commenters (TV-D-05,
IV-D-12, and IV-D-16) also supported EPA's rejection of a "beyond-the-floor" MACT limit for
Combustion Turbine Cells. Commenter IV-D-05 noted "emissions controls at an aircraft engine test
cell/stand pose potential safety concerns not fully addressed in the record. Specifically, such emissions
controls could potentially compromise flight safety by imposing back pressure on the testing operation."
Commenter IV-D-12 supported EPA's conclusion that above-the-floor controls on rocket engines are
not appropriate.
Commenter IV-D-16 added specific concerns about the technological feasibility of any turbine
controls. The commenter also supported EPA's conclusion that above-the-floor controls on existing
facilities in the 25 hp internal combustion engine subcategory are not appropriate. The commenter
recommended that EPA revise the preamble discussion to more clearly state that there are no controls
on any existing jet engine turbine test cells, and that it is not technologically feasible to control emissions
from such test cells.
Response: No response needed.
2.4 NEW SOURCE MACT
2.4.1 Comment: One commenter (TV-D-10) recommended that EPA should acknowledge
the inherently low emissions and unique characteristics of on-road diesel engines by providing an
alternative standard for the testing of these units: (1) a standard for new diesel engine test cells should
be expressed in terms of THC, and (2) the established THC standard should correspond with the HC
standard of the 2007 Rule, equivalent to 0.14 g/hp-hr.
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Response: As we learned in our discussions with industry representatives during the regulatory
development process, we know that some current engine test requirements do not involve HAP or CO
measurements, and we have established an alternate THC standard to provide added compliance
flexibility. The THC standard included in the final rule is a maximum of 20 parts per million (ppm) outlet
concentration or 96 percent reduction. It is not possible to provide an emission limit standard
equivalent to the suggested 0.14 g/hp-hr, which is based on power.
2.4.2 Comment: Two commenters (TV-D-11 and FV-D-12) supported EPA's determination
that new source controls for Combustion Turbine Engines are not appropriate.
Response: No response needed.
2.4.3 Comment: Several commenters (TV-D-03, IV-D-05, IV-D-08, IV-D-15, IV-D-16,
IV-D-17, IV-D-19, IV-D-24,1V-F-01, IV-F-02, and IV-F-03) stated the proposed new source
emissions limits (99.9 percent CO emission reduction or 5 ppmv CO outlet concentration) are too
stringent or are not attainable. The commenters further stated that the data used as the basis for setting
the MACT floor limit are not representative of all engine testing, and the limits should reflect real world
applications. Commenter IV-D-17 stated that EPA should revise its analysis for engine test cells/stands
testing natural gas-fired reciprocating internal combustion engines based on the levels of reduction
achieved in the EPA-sponsored emissions testing at the Colorado State University Engines and Energy
Conversion Laboratory.
Some of the commenters encouraged EPA to adopt more reasonable emissions limits.
Commenter IV-D-24 recommended a control efficiency between 90 and 95 percent for CO.
Commenter IV-F-02 recommended a control efficiency of 95 to 96 percent for CO. Commenter
IV-D-19 recommended a CO control efficiency of 95 percent. Commenter IV-D-08 recommended
that EPA adjust the emission limits as necessary to ensure that they are achievable on a continuous
basis throughout the engine operating envelope at both steady-state and transient operating conditions
by the engine(s) being tested. Commenter IV-D-24 recommended that EPA use the catalyst
performance data available from the ICCR CSU testing and aftertreatment manufacturer-guaranteed
destruction efficiencies for CO and THC to set reasonable and achievable performance requirements
for the proposed rule for diesel engines.
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Two commenters (IV-D-15 and IV-D-16) recommended that the standard be revised to the
following levels and that compliance may be demonstrated through conformance with any one of the
four compliance limits: (1) CO control of at least 97 percent, (2) exhaust CO level of 35 ppm or less
(dry basis adjusted to 15 percent oxygen, (3) THC control of at least 95.9 percent, or (4) exhaust
THC level of 35 ppmvd or less (dry basis adjusted to 15 percent oxygen). Because the effectiveness
of catalytic reduction technology varies with the type of engine, one commenter (TV-D-03)
recommended that EPA develop a series of applicable CO and THC reduction standards that are
based upon engine subcategories being tested and the currently available control technology for each
subcategory. The following percentages were recommended for control technologies for both CO and
THC: gasoline engines, 90 percent; diesel engines, 90 percent; 2-stroke gaseous engines, 80 percent;
and 4-stroke gaseous engines, 90 percent.
Response: In the proposed rule, we used the best information available to us at the time to
determine MACT for both new and existing sources. We have reviewed the additional test data
submitted during the comment period (see docket item FV-D-19), as well as the various comments
describing test conditions that are significantly different from those used in previously submitted test
reports. We also evaluated other rules requiring similar combustion control equipment. The Paper and
Other Web Coating NESHAP, subpart JJJJ, has an option of meeting overall emission reductions of
98 percent. This destruction efficiency achieved through thermal oxidation was generally accepted as
the "level of control achievable on a continuous basis under all normal operating conditions applicable
to new sources." Therefore, for that particular source category (which involves coatings and cleaning
solvents), EPA determined that thermal oxidation was the best control technology and justified setting
the emission limits for thermal oxidizers at 98 percent control efficiency or alternatively, achieve an
outlet concentration of 20 ppm or less.
With this control technology limit in mind, we then compared the two source categories for
similarities and/or differences that could lead to a comparable level of destruction efficiency for engine
test cells/stands. Coating operations covered by the Paper and Other Web Coating NESHAP contain
large concentrations of solvents that are easily removed through thermal oxidation. Engine testing by-
products, on the other hand, are the result (by-products) of an incomplete combustion process and
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HAPs are typically emitted in significantly lower concentrations than surface coating and solvent
cleaning emissions. As noted by the commenters, there are a variety of fuels and test conditions used at
different sources for several types of engine tests. (A summary of the submitted test reports and
emissions data is included in the docket, item IV-B-1.) In reviewing the test data submitted by the
commenters, we found that even though some of the test reports showed very high destruction
efficiencies for thermal oxidizers, the best controlled facilities were only being required to meet 95 or
96 percent VOC control, based on their operating permit requirements. These levels of control are
consistent with the limits recommended by commenters IV-D-15, IV-D-16, IV-D-19, and IV-F-02
and take into consideration differences in operating conditions for engine test cells/stands. After
reviewing the comments and information submitted, we conclude that a maximum control level of
96 percent is appropriate once we consider the differences in HAP emission levels from engines tested,
the testing conditions, and also the need to account for measurement uncertainties. Therefore, the new
source emission limits have been changed in the final rule to 96 percent reduction for CO or THC
based on the updated test data, additional test reports, and estimates reflecting the most prevalent
engine test setups and conditions across all engine testing sectors involving engines greater than or equal
to 25 hp. We also agree with the commenters in that some engine tests have inherently lower CO and
THC emission streams. In order to provide additional flexibility to such emission sources while still
achieving an acceptable level of control, we are providing an alternate outlet concentration emission
limit of 20 ppm for either CO or THC emissions. The 20 ppm outlet concentration limit correlates to
the level of control identified in the Paper and Other Web Coatings rule, as well as the specified test
method detection limit associated with several of the test reports provided by the commenters.
2.4.4 Comment: One commenter (TV-F-02) made specific comments concerning the test
data used to set the emission limits:
The outlet temperature for the tests ranged between 1000 and 1300 degrees
Fahrenheit. Typical exhaust temperatures are less than 500 degrees. Additionally, on
one of the units the measured outlet oxygen concentration was greater than the inlet
concentration. This is not technically possible, validating our concerns over the validity
of the test data.
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Response: We have re-evaluated the test data and verified the information noted by the
commenter. We have revised the new source MACT emission limits based on updated test data,
additional test reports, and estimates reflecting the most prevalent engine test setups and conditions
across all engine testing sectors involving engines greater than or equal to 25 hp.
2.4.5 Comment: Several commenters (TV-D-03, IV-D-06, IV-D-09, IV-D-16, IV-D-19,
IV-D-24, FV-F-01, and FV-F-02) stated that although oxidation technologies can in practice achieve
CO destruction rate efficiencies of 99.9 percent or 5 ppm at 15 percent O2, typically vendors do not
guarantee systems at these levels.
Response: We contacted several control equipment vendors and were quoted CO destruction
rate efficiencies ranging from 95 to 99.9 percent. However, the vendors also indicated that the actual
value depends on several site-specific and process-specific parameters. This information provided
additional support for revising the MACT floor emission limits) to reflect real world applications from
the various sectors.
2.4.6 Comment: Several commenters (IV-D-05, IV-D-15, and IV-D-16) supported EPA's
conclusion that above-the-floor controls on new or reconstructed facilities are not appropriate.
Response: No response needed.
2.4.7 OanmSDl: Several commenters (IV-D-03, IV-D-04, IV-D-13, IV-D-15, IV-D-16,
IV-D-23, FV-D-24, IV-F-01, and F/-F-03) endorsed EPA's suggestion that the facility should be
allowed the choice of using either CO or THC measurements to demonstrate the performance of the
control equipment. Commenter IV-D-16 noted that it would be arbitrary for EPA to refuse to allow
the measurement of THC to substitute for the measurement of CO, because EPA's authority rests on
the destruction of HAP and not on the destruction of CO.
Response: We appreciate the commenters' concurrence on this issue. The final rule includes
provisions for measuring either CO or THC to comply with the emission limits for new or reconstructed
engine test cells/stands used to test engines rated at or above 25 hp. The emission limits included in the
final rule are expressed in terms of overall control efficiency (percent reduction) or outlet concentration
(ppm).
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2.5 RECONSTRUCTION
2.5.1 Comment: One commenter (TV-D-04) requested clarification on whether the rule
should apply if reconstruction is done in segments costing less than SO percent per segment but totaling
more than 50 percent cumulatively, and if so, what the period of time over which the costs would be
applied to the total cumulative cost would be.
Response: Reconstruction costs cannot be broken into phases to avoid triggering new source
MACT requirements. This phasing (or fragmentation) of reconstruction activities was previously
addressed in the preamble to the proposed amendments to the General Provisions, 66 FR 16318
(March 23, 2001). "Sources cannot phase reconstruction activities to avoid applicable new source
requirements... activities that are fragmented or phased to stay within the 50 percent of fixed capital
cost criteria in item (1) of the definition of "reconstruction" in 63.2 shall be considered together for
applying that criteria. Periodic replacement of equipment to maintain production to meet product
demands should not be aggregated for determining whether reconstruction has occurred [66 FR
16325]."
Using the above guidance, if the total cost of the reconstruction (even if the work is conducted
over a time period of several years) is greater than 50 percent of the original fixed capital cost of the
affected source, the reconstructed source would be subject to new source MACT.
2.5.2 Comment: Ten commenters (IV-D-03, IV-D-10, IV-D-14, IV-D-19, IV-D-21,
IV-D-23, IV-D-24, IV-F-01, IV-F-02, and IV-F-03) recommended changing the definition of
"reconstructed source" and provided specific recommendations. Four of the commenters (TV-D-03,
IV-D-23, IV-D-24, and IV-F-01) requested that the definition include only changes to the test
cell/stand that result in capacity increases. Five commenters (IV-D-03, IV-D-19, IV-D-24, IV-F-01,
and IV-F-02) requested that the definition include changes to test cells/stands that result in HAP
emission increases. Two commenters (IV-D-03 and IV-D-19) recommended that EPA include a
modified definition of "reconstruction" in the final rule that would add to the General Provisions
definition in 40 CFR §63.2 an exclusion for the cost of replacement or modification of components
required to demonstrate compliance with EPA's emission regulations contained in 40 CFR part 89,90,
and 91. Commenter IV-D-03 recommended that the definition of reconstructed be changed to reflect
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the fact that engine test cells are continuously upgraded in response to EPA certification requirements.
The commenter stated that manufacturers may be forced by regulation to invest in new equipment for
test cells and fall under the definition of reconstruction in order to comply with new EPA engine
requirements, even though such improvements will not change the capacity or emissions from the cell.
A specific definition of reconstruction needs to be applied to engine test cells that only counts costs
incurred to increase capacity or if the modification results in increased HAP emissions. The commenter
further stated that EPA has previously recognized this problem and adopted a reasonable approach in
the final Large Municipal Waste Combustor rule (40 CFR 60.50a(f) and 60.50b(d)), and that the same
reasoning could be applied to engine test cells.
Commenter FV-D-10 indicated that EPA should be careful in its definition of the affected
source to avoid unintended consequences that would lead to costly compliance measures without any
environmental benefit. For existing test cells, only replacement of a dynamometer to increase the size of
the engine that can be tested should constitute a major modification triggering MACT. Commenter
IV-D-14 requested that EPA provide a clear definition for "reconstructed source," and consider
reconfiguration of equipment and the extent of support equipment included. Commenter FV-D-24
recommended that EPA consider the unique aspects of engine test cells/stands and define
"reconstructed" to include only those changes that result in increased capacity or emissions potential of
the test cell/stand in the 50 percent cost benchmark, and specifically exclude passive measurement and
control instrumentation and electronics. Commenter IV-D-03 recommended that the definition of
new/reconstructed be changed to reflect the fact that engine test cells are continuously upgraded in
response to EPA requirements, thus the definition should only count costs incurred to increase capacity
or modifications that result in increased HAP emissions. Commenter FV-D-24 recommended that EPA
clarify what it would consider "technologically and economically feasible." The commenter stated that it
may be difficult or expensive as a practical matter to isolate "reconstructed" test cells/stands from pre-
existing ones (e.g., test cells configured with a manifold ventilation system).
Response: In our amendments to the General Provisions, we addressed the definition of
"reconstruction" (66 FR 16582) (April 5,2002). Therefore, the definition of "reconstruction" is
beyond the scope of this rulemaking. This response is to provide clarification and thereby explain the
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applicability of "reconstruction" to the engine test cell/stand standard. We are not reopening the
definition of "reconstruction" in this rule.
In the amended General Provisions, "Reconstruction, unless otherwise defined in a relevant
standard, means the replacement of components of an affected or previously nonaffected source to
such an extent that:
(1) The fixed capital cost of the new components exceeds 50 percent of the fixed capital cost
that would be required to construct a comparable new source; and
(2) It is technologically and economically feasible for the reconstructed source to meet the
relevant standard(s) established by the Administrator (or a State) pursuant to Section 112 of the Act.
Upon reconstruction, an affected source, or a stationary source that becomes an affected source, is
subject to relevant standards for new sources, including compliance dates, irrespective of any change in
emissions of HAPs from that source (see also, 40 CFR §63.2 (2002))."
Because of the diversity of engine test cells/stands and test requirements used by the various
types of engine manufacturers and industry sectors, it is difficult to define what types of test equipment
and support equipment comprise an actual engine test cell/stand (e.g., affected source) or reconstructed
source. We cannot limit or define reconstruction to include only those changes that will increase
capacity or HAP emissions associated with the engine test cell/stand because there is no way of
knowing how the engine test cell/stand will be used in the future. However, we do not consider
equipment reconfiguration to be reconstruction.
In response to these comments we have included new language in the final rule clarifying that
changes made to an existing engine test cell/stand primarily for the purpose of complying with revisions
to the engine testing requirements under 40 CFR parts 80, 86, 89,90,91, or 92 are not considered a
modification or reconstruction. Many existing engine test cells are used to comply with regulations for
mobile sources under Title 40 of the Code of Federal Regulations. These provisions outline the test
procedures that are to be followed to determine compliance with the applicable mobile-source emission
standard. The test procedures periodically undergo revisions that may result in modifications to the
engine test cells and the test equipment therein. Changes to the test procedures are usually
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incorporated to accommodate the use of new test equipment. In addition, changes may be made to
ensure the accurate measurement of exhaust emissions as a result of a more stringent emission standard.
We agree with the commenter that it is appropriate to exclude existing affected sources that
are modified to meet revisions under Title 40 provisions. We believe that it is unnecessary to require
these existing affected sources to install emission control devices when modifications are due to changes
to the federal mobile source regulations and since those improvements will not increase the capacity or
the emissions from the affected source.
In support of their position commenters cite the regulations for Large Municipal Waste
Combustors in 40 CFR 60.50a(f) and 60.50b(d) which establish that physical or operational changes
made to an existing unit primarily for the purpose of complying with emission guidelines under subpart
Cb are not considered a modification or reconstruction. We recognize the precedent set by these
provisions with respect to the exclusion of costs for required modifications to comply with other EPA
regulations. We have reviewed the regulatory language in these regulations and conclude that it is
appropriate to provide a similar level of flexibility to engine test cells/stands. Therefore, existing
affected sources modified to meet revisions to the requirements in those parts cited above will not be
subject to new source MACT.
2.5.3 Comment: One commenter (TV-D-21) requested clarification regarding the
replacement of existing engines with different engines (which is part of the normal testing cycle) and
whether that could be interpreted as "reconstruction."
Response: For purposes of determining reconstruction, the engines being tested in the test
cell/stand are not considered part of the affected source. The replacement of engines in an engine test
cell/stand is part of the normal test process. Some QA/QC tests will require only that the engine be run
(tested) for a few minutes, whereas other durability tests could run for several hours or months.
Therefore, engine replacement activities would not be considered as reconstruction.
2.6 MONITORING REQUIREMENTS
2.6.1 Comment: Several commenters (IV-D-03, IV-D-10, IV-D-13, IV-D-15, IV-D-16,
IV-D-17, IV-D-19, IV-D-23, IV-D-24, IV-F-01, IV-F-02, and IV-F-03) requested that the
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continuous emissions monitoring systems (CEMS) requirements be eliminated or changed to parametric
monitoring. The commenters stated that CEMS are too expensive and do not provide any meaningful
environmental benefit to justify the capital costs to install them on engine test stands. They also pointed
out that in other permitting decisions and guidance documents, EPA has determined that initial stack
tests followed by monitoring of operating temperature is a proven and cost-effective way of monitoring
oxidizer performance.
Commenter FV-D-24 stated that exhaust stream composition, temperature, and flow rate from
test engine cells/stands vary considerably due to the variety of engines tested, and there is a significantly
higher number of start/stop cycles compared to any other CEMS application. Commenters IV-D-19
and IV-F-02 cited vendor comments concerning the ability and reliability of a CEMS to accurately
measure the proposed concentrations.
Response: We have reviewed the monitoring requirements for the proposal and compared
them with other similar emission sources. The HAP emitted by engine test cells are the result of
byproducts of incomplete combustion. Thermal destruction of these HAP occurs at temperatures
between 590°C and 650°C (1,100°F and 1200°F), thus making temperature an appropriate parameter
to monitor the destruction of HAP. In the case of monitoring an RTO, the temperature is monitored
during the initial performance test After the RTO meets the performance test requirements and
demonstrates compliance with the applicable emission limit, the operating temperature is continuously
monitored to verify the performance of the RTO. As a result, we have concluded that parametric
monitoring is adequate for ensuring compliance with the emission limit. Thus, we have changed the
monitoring requirements in the final rule to allow parameter (temperature) monitoring for thermal
oxidizers. Since some facilities may already have existing continuous monitoring equipment in place,
CEMS are still included in the final rule as a monitoring option.
2.6.2 Comment: One commenter (TV-D-17) offered input regarding the current capabilities
of CO CEMS technology and the feasibility of CO CEMS. The commenter stated that we indicated
CEMS are available to accurately measure CO emissions at the low concentrations found in the
exhaust stream of an engine test cell/stand following an emission control device, such as oxidation
emission controls, but did not reference any materials in the Air Docket to support the assertion.
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According to the commenter, vendor claims for CO CEMS and CO instrumental analyzers, unless
accompanied by test data obtained under known and controlled conditions, should not be considered
adequate proof of availability and performance.
The commenter cautioned EPA to consider carefully comments from instrumentation vendors
due to the obvious commercial interests and the fact that, when those claims must be tested in a
regulatory context (including performance specifications for daily calibrations, quarterly audits, and
annual performance certification), those claims often fall short The commenter also provided specific
examples of technical issues related to the proposed test methods. One of the examples involved:
"Equipment-specific technical hurdles affect the feasibility of CO CEMS, including the ability of the
system to perform adequately with the pulsating exhaust flow typical for reciprocating engines, and the
ability of a CEMS to adequately sample, condition, convey to the CO monitor, and analyze a
representative exhaust sample."
Response: In response to the commenter's concern about the CEMS requirement(s), the final
rule now allows the use of continuous parametric monitoring systems (CPMS) to demonstrate
compliance with either emission limit (percent reduction or outlet concentration). At most facilities, the
parameter used to demonstrate compliance will be the operating temperature for the thermal oxidizer,
which will be correlated to the suitable operating temperature range derived during performance testing.
CEMS are still included in the final rule as a monitoring option, as described under the response to
comment 2.6.1. We have also revised the emission limits for new or reconstructed engine test cells
testing engines with power ratings greater than or equal to 25 hp. The revised limits are 96 percent
reduction in CO or THC emissions or an outlet concentration limit of 20 ppm corrected to 15 percent
oxygen.
Revising the limit to 20 ppm corrected to 15 percent oxygen eliminates concerns with
measuring low emission levels by bringing the limit into the normal working range of Method 10.
Performance specification 4A was specifically designed for CO CEMS regulated in this range and
incorporates the alternate provision for low-concentration accuracy determination noted by the
commenter. There are a number of regulated industries (mostly under State permits) that currently test
and monitor CO at the 20 ppm level. Tests at these sources have shown that Methods 10 and 3 A,
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Performance Specifications 2 and 4, and Procedure 1 of Appendix F are adequate for determining
compliance at this revised level.
2.6.3 Comment: Commenter IV-D-17 requested EPA revise Reference Method for CO and
Performance Protocols for CO CEMS.
The use of CEMS is complicated by the fact that CEMS application for measurement
of emission levels commensurate with the proposed standard is unproven and beyond
the scope of the requisite federal performance protocols in 40 CFR 60, Appendices A,
B, and F.
In the Engine Test Cell MACT proposal, EPA recognizes the inadequacies of
Performance Specification 4A (PS4A) for CO CEMS and Method 10. However,
EPA has railed to mention the inadequacies of Performance Specification 3 (PS3) for
O2 CEMS, Reference Method 3A for O2 measurements, and Appendix F, Procedure
1 (QA procedures for CEMS used for compliance monitoring) as they would apply to
measuring CO emissions from engine test cells/stands.
A number of examples are possible to indicate the problems associated with existing
procedures. One example will be discussed regarding Appendix F, Procedure 1. The
CO concentration limit proposed in the Engine Test Cell MACT is expressed in terms
of ppmvd CO corrected to 15% O2. The O2 correction factor is 5.97(20.9 - %O2). It
can easily be seen that as O2 approaches 20.9%, the correction factor increases
exponentially. This means that the measurement of O2 directly affects the final
determination of compliance. The performance specifications in PS3 and Reference
Method 3 A and the out-of-control specifications of Procedure 1 allow large amounts of
error so as to make the determination of compliance uncertain. For example, PS3
allowed drift is 0.5% O2. This would introduce an uncertainty of 8.5% in the CO
concentration at an O2 concentration of 15%. hi PS3, the relative accuracy
specification is 1% O2. This relative accuracy specification would introduce an
uncertainty of 16.9% in the corrected CO concentration. The uncertainty based on the
present performance specifications in Reference Method 3A has been estimated to be
4.29% of span or 1.07% O2 for a span of 25% O2. At 15% O2, a ±1.07% O2
uncertainty results in ±18.14% uncertainty in the corrected CO concentration and this
does not include the uncertainties involved with the actual measurement of CO. This
discussion, that considers only issues associated with O2 measurement allowances
inherent to the technologies and procedures, indicates the type of issues that exist.
EPA also notes that, although Method 10 is specified in the Engine Test Cell MACT
proposal as the reference method to certify the performance of the CO CEMS, the
performance criteria in addenda A of Method 10 have not been revised recently and
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are not suitable for GEMS at the CO concentrations necessary to demonstrate
compliance with the proposed Engine Test Cell MACT. EPA indicates that the
Agency believes the range and minimum detectable sensitivity should be changed to
reflect target concentrations as low as 1 ppm CO in some cases. However, EPA
provides no information to support that assertion. Also, EPA does not reference any
materials in the Air Docket to support the assertion. Rather, the Agency requests input
regarding the changes that should be made to the performance criteria in Method 10.
In order to develop low-level CO measurement methods, EPA will have to develop
technology-specific procedures to determine and demonstrate minimal detection limits
and practical quantification limits as well as the accuracy and precision of the final
measurement methods. These have proven to be very difficult demonstrations. For
example, for NOX, there are still unresolved issues for the measurement of low
concentrations, which has been an area of study for a number of years.
As proposed, Method 10, PS4A, Method 3A, PS3, and QA Procedure 1 are integral
parts of the rule. It is inappropriate that these protocols, with the deficiencies noted by
EPA and above, are included in the Engine Test Cell MACT proposal prior to an
opportunity for affected parties to review and comment on the changes that would have
to be made to correct the numerous deficiencies. The changes necessary to correct
these deficiencies would require rulemaking (proposal and promulgation) and would
delay the promulgation of the emission standards.
Response: We agree with the commenter that accuracy and uncertainty concerns exist when
current test methods and performance specifications are applied to CO concentrations around 5 ppm.
The concerns are compounded when oxygen measurements are also made to correct the concentration
to a reference level.
Revising the limit to 20 ppm corrected to 15 percent oxygen reduces these concerns by
bringing the limit into the normal working range of Method 10. Performance specification 4A was
specifically designed for CO CEMS regulated in this range and incorporates the alternate provision for
low-concentration accuracy determination noted by the commented. There are a number of regulated
industries (mostly under State permits) that currently test and monitor CO at the 20 ppm level. Tests at
these sources have shown that Methods 10 and 3A, Performance Specifications 2 and 4, and
Procedure 1 of Appendix F are adequate for determining compliance at this revised level.
2.7 COST AND ECONOMIC ASSUMPTIONS AND IMPACTS
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2.7.1 Comment: One commenter (TV-D-06) stated that although EPA estimated the annual
monitoring reporting and recordkeeping burden for the rule at 9,600 labor hours per year at a total
annual cost of $440,888, turbine oxidation catalyst owners and vendors uniformly allow for less than
0.5 hour per day required for operating and maintaining an oxidation catalyst
Response: In determining the cost impacts associated with complying with the proposed engine
test cells/stands NESHAP requirements, we used a high-end estimate of the labor hours for monitoring
activities. These labor estimates are consistent with other rules with similar monitoring requirements.
2.7.2 Comment: One commenter (TV-D-19) stated the proposed rule underestimates costs
because it fails to account for those existing sources that will have to comply with new source MACT
due to compliance with other emission control regulations.
Response: We believe the cost estimates are appropriate and represent the impacts to the
overall industry. With the revised definition of "affected source" in the final rule, we estimate that fewer
facilities that add or modify existing engine test cells/stands are likely to be subject to the new source
MACT requirements. Furthermore, any existing affected source that is modified or reconstructed to
comply with certification testing requirements related to mobile source (Title IT) regulations will not be
impacted by the final rule and this will result in fewer affected sources with control requirements and a
lower overall cost impact. Section 63.9290(a)(3) of the final rule states "Changes made to an existing
affected source primarily for the purpose of complying with engine testing requirements under 40 CFR
parts 80, 86, 89,90,91, or 92 are not considered a modification or reconstruction. In addition,
passive measurement and control instrumentation and electronics are not included as part of any
affected source reconstruction evaluation."
2.7.3 Comment: One commenter (TV-D-06) stated that EPA's expectation that the rule will
reduce air toxic emissions by 135 tpy at a national annual cost of $7.4 million — or approximately
$55,000 per ton reduction each year — seems very high, particularly when considering the simplicity of
an oxidation catalyst. The commenter stated that the cost for an oxidation catalyst can be greatly
distorted by applying generic and more complex cost factors for other pollution control technologies.
Response: The estimated costs were based on the most recent EPA cost procedures, as
referenced in the Engine Testing Control Costs memorandum (docket item n-B-17). We evaluated the
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cost of various control devices and collected information from those facilities with existing controls. The
cost effectiveness value is driven by the HAP reduction more so than the capital and operational costs
of the control equipment, which are in-line with similar equipment requirements of several other rules.
As a result of the revised definition of "affected source" in the final rule, we estimate that there
will be fewer affected source facilities (18 instead of 37) and the corresponding HAP emissions
reduction is now estimated to be 65.5 tpy (instead of 135 tpy). The estimated cost is now $3.2 million
(instead of $7.4 million).
2.8 STARTUP, SHUTDOWN, AND MALFUNCTION (SSM)
2.8.1 Comment: Several commenters (IV-D-03, IV-D-15, IV-D-16, IV-D-17, IV-D-24,
IV-F-01, and IV-F-03) recommended that the SSM provisions under 63.6(e)(3) and 63.6(f)(l)
extend to the final engine test cells/stands rule. Commenter IV-D-03 noted that rather than being a
steady-state operation, as is the case for other stationary sources, engine tests involve a continuum of
startup and shutdown as well as different operating and emissions conditions, and manufacturers and
test cell operators need the flexibility allowed by the general provisions in order to operate successfully.
Commenter IV-D-17 recommended that EPA include the MACT General Provisions for SSM so that
deviations during a period of SSM are not violations of the Engine Test Cell MACT if the source is
operated in accordance with the SSM plan (SSMP). Commenter IV-D-24 recommended that EPA
should specifically adopt those sections of the General Provisions allowing an SSMP to minimize
emissions from engine test cells/stands during those phases of their operation.
Response: We agree with the commenters' point that "engine tests involve a continuum of
startup and shutdown as well as different operating and emissions conditions." The engine testing
process is different than most steady-state processes, and this difference serves as the main reason we
did not adopt the SSM provisions from the General Provisions. If we were to adopt the SSM
provisions, most of the emissions from engine test cells/stands would not be covered by the emission
limits but would instead fall under the SSM provisions. This would likely result in increased HAP
emission levels from engine test cells/stands. One example of HAP emissions that we want to control
and minimize involves engine endurance testing. The purpose of endurance testing (which is typically
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conducted over several days or months) is to run an engine until failure, which can result in an emissions
spike. Because the engine failure is an expected event under some conditions (at some point in time),
the associated emissions spike is also an expected event, and we want to capture and control those
HAP emissions.
2.8.2 Comment: One commenter (IV-D-15) requested that the General Provisions SSM
provisions be applied to the engine test rule. The commenter wants to use the option of complying with
catalytic oxidizers and wants the startup period during which the catalytic oxidizer comes up to
operating temperature excluded. The commenter also provided examples of issues involving oxidizer
malfunctions: (1) engines cannot be shut off instantaneously, and excess emissions can occur in the time
that it takes to complete an orderly and safe shutdown, and (2) there are certain tests that must be
redone at large cost if they are interrupted. An example piston scuff test was described by the
commenter as taking about 90 minutes, and if the engine is shutdown, the engine must be rebuilt and the
test rerun. In the case of an oxidizer malfunction when such a test is in progress, the operator should be
able to complete the test that is under way without risk of enforcement action.
Response: Although the commenter makes valid points regarding SSM provisions, the majority
of emissions from engine testing occur during the times covered by SSM provisions. Regarding the
time required for a catalytic oxidizer to come up to operating temperature, no engine testing should be
conducted before the minimum operating temperature (determined during the initial performance test) is
achieved. Because the SSM provisions apply to the process as well as the control equipment, the
impact of the engine test NESHAP to minimize HAP emissions would be significantly reduced by
adopting the SSM provisions. However, based on the above comments, we decided to include SSM
provisions for any control equipment and monitoring equipment related to engine test cells/stands
emissions. New language has been added to the final rule that references the General Provisions for
SSM procedures related to control equipment and associated monitoring equipment. Table 6
(Applicability of General Provisions to Subpart PPPPP of Part 63), located at the end of the final rule,
has also been updated to reflect this change.
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2.9 COMPLIANCE PROCEDURES
2.9.1 Comment: One commenter (IV-D-10) recommended that EPA should extend the
averaging time for demonstrating compliance to 1 month because the proposed 4-hour rolling average
compliance foils to accommodate the inherent variability of emissions from diesel engine test stands. In
addition, the low risk posed by emissions from test cells further warrants an expansion of the averaging
period.
Response: Based on the data used to establish the emission limits, a 4-hour averaging time is
appropriate. The 4-hour rolling average time period required to demonstrate compliance is based on
the MACT database information, which came from submitted test data using an average of three
1-hour test runs. The initial performance test requirement for this rule also requires three 1-hour test
runs.
2.9.2 Comment: Two commenters (TV-D-15 and IV-D-16) stated that EPA should allow
the use of either the standard methods of measurement under stationary source rules or those of mobile
source rules when demonstrating compliance in the initial stack test, given that many of the engines that
will be subject to this standard are being tested for CO and THC levels in order to comply with the
requirements established under Tide n of the Act
Response: The initial performance testing requirements may or may not be the same as the
testing required by another regulation. The testing may have different test conditions (now or in the
future), and the results may not correlate with the regular stack test results. The engine test final rule
applies only to stationary sources located at major source facilities, and only the emission limits and test
requirements from the final engine test cells/stands NESHAP are applicable.
2.10 COMPLIANCE DATES
2.10.1 Comment: One commenter (TV-D-09) requested that EPA reconcile the differences
regarding compliance dates that exist between the preamble language and the proposed regulatory text
in favor of the approach described in the preamble (this in addition to the flexibility afforded to projects
that were already under contract on the date the rule was proposed). This commenter supported the
3-years-fiom-promulgation compliance deadline for projects initiated after the proposal date.
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One commenter (IV-D-04) recommended adding a time frame of 3 years for compliance after
the date the final rule is published in the Federal Register. Commenter FV-D-04 stated that "3 years
would allow ample time to fine tune the equipment and reinforce procedures before regulatory scrutiny
begins." Then, "new start ups could take effect immediately."
Response: We made an inadvertent error in the proposal preamble concerning the compliance
time period. The proposal preamble language was incorrect, and the proposal regulatory text was
correct. We have reconciled the noted differences in the final rule. Existing affected sources have
3 years after the effective (promulgation) date to comply with the final rule requirements. New sources
will have to comply on the effective date or upon startup, whichever is later.
2.10.2 Comment: One commenter (TV-D-17) discussed the need for a compliance deadline
longer than 3 years. The commenter stated that, typically, new or reconstructed sources must comply
with MACT requirements upon startup or upon promulgation of the final rule. The commenter also
pointed out the proposed MACT rule provides no relief for owner/operators if the Agency fails to
address the deficiencies in the performance protocols prior to the compliance deadline. The
commenter cited examples in which development of new or revised test methods has taken 3 to
5 years. In addition, EPA typically requires extensive technical laboratory and field evaluations to
assess test method performance. Therefore, the process to make revisions to the EPA protocols will
require more than the 3 years contemplated in the proposed rule.
Response: The final rule includes new emission limits that do not require modifications to any
existing test protocols. Therefore, we are not deviating from our previous determination for any of the
required testing or test methods.
2.11 AVERAGING
2.11.1 Comment: Eight commenters (IV-D-03, FV-D-08, IV-D-09, IV-D-10, IV-D-13,
FV-D-15, IV-D-16, and IV-D-19) recommended that averaging provisions be included in the final rule.
Commenter IV-D-19 stated that emissions averaging is good policy that should be included in the final
rule and recommended two options: (1) allow averaging across all engine test cells at a facility to
comply with the new source MACT limit and (2) average across the entire facility, allowing reductions
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at other HAP-emitting operations to offset a new or reconstructed source. Commenter FV-D-09 stated
that emissions averaging between existing and affected units is an essential element of any commonsense
approach to the engine testing MACT because emission units with intermittent activity (such as those
used for design development and emission testing) are often located at the same site as emission units
operated under more steady-state conditions (e.g., endurance test stands). Commenter IV-D-IO
supported averaging emissions across processes as a compliance option, which would result in reduced
cost and environmental burden. Two commenters (TV-D-15 and IV-D-16) strongly supported the
concept in Section V of the preamble of averaging emissions across processes throughout the entire
major source and allowing reductions from emission points within the facility covered by other MACT
standards to be counted towards the emissions limitations in this proposed rule.
Response: We have looked at existing rules that include averaging provisions such as the
Petroleum Refineries NESHAP (subpart CC), the Aluminum Reduction Plants NESHAP (subpart LL),
and the Group IV Polymers and Resins NESHAP (subpart JJJ), and found that these rules allow
averaging only between emission sources covered under each specific rule. In reviewing the comments
and considering different averaging options there were several issues taken into account. First, in all
previous regulations that implemented an averaging scheme, only processes within the same source
category were considered and accounted for. In other words, the concept of emissions averaging has
always been considered and implemented within a given source category, and not across source
categories. Second, only existing sources have been allowed to take part in this type of flexibility
option. This decision to not allow new sources to average their emissions is consistent with the
direction outlined in the statute where new sources are expected to reduce their emissions to a level
equivalent to that of the best controlled similar source. Many facilities that operate engine test
cells/stands also conduct other processes that emit HAP. However, these other processes, such as
coating and cleaning, are not part of the engine test cells/stands source category and are already
regulated under other NESHAP. For these reasons we have concluded that averaging emissions is not
an appropriate option for this source category.
2.11.2 Comment: One commenter (TV-D-08) noted that any averaging scheme must ensure
that facility-wide emissions of the four predominant HAPs emitted by engine test facilities (benzene,
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toluene, xylene isomers, and 1,3-butadiene) are decreased by the amount that they would have been if
the affected test stands met the emission reduction percentage or emission concentration. The
commenter also noted that an averaging scheme must ensure the facility does not increase emissions of
other HAPs in its effort to decrease emissions of the four HAPs targeted by the rule. The commenter
described concepts averaging emissions with: (1) other engine test stands, (2) other stationary
combustion sources, (3) mobile sources, and (4) all sources. The commenter recommended that EPA
consider the averaging concepts discussed and allow facilities to comply with this rule by averaging
emission reductions from affected test stands and other air emission units.
Response: The specific HAP emitted by engine test cells/stands and the fact that most other
processes present at engine test facilities emit different HAPs was another consideration in our decision
not to include an averaging provision in the final rule. As the commenter argued, an averaging scheme
must consider the fact that HAP emissions may increase under some conditions and the fact that a
facility may be decreasing emissions of one pollutant while increasing emissions of another, more toxic
one. The suggestions provided by the commenter, however, do not show how they address the
questions raised here and under the response to comment 2.11.1. Therefore, averaging provisions are
not included in the final rule.
2.11.3 Comment: Two commenters (TV-D-15 and IV-D-16) recommended that HAP
emission reductions from emissions points within the facility but not covered by other MACT standards
should be counted towards the emissions limitations in the proposed rule, along with emission
reductions from emission points that are covered by other MACT standards.
Response: We considered this as part of the development of the proposed rule but decided
that only other emission sources subject to the same MACT standards could be used in any averaging
provisions in order to make the MACT requirements consistent, understandable, and enforceable.
2.11.4 Comment: Two commenters (TV-D-15 and IV-D-16) provided guidance on the
implementation of the averaging provisions. Both commenters suggested that averaging be implemented
through title V permits, with otherwise unregulated emissions points subject to enforceable permit
limitations in order to ensure that the reductions are real and that they at least fully offset the foregone
reductions.
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Response: Because of differences between States and permitting programs, we decided that
any attempt by EPA to coordinate MACT through title V permits to somehow allow emissions
averaging would be too difficult and confusing to implement The title V program incorporates all
relevant MACT requirements and the averaging provisions included in the final engine test rule should
be incorporated into all applicable title V permits.
2.12 MISCELLANEOUS
2.12.1 Comment: One commenter (TV-D-04) noted that in the supporting text on
page 34552, question G, the reference for CO PEMS performance specification reads, "40 CFR part
60, appendix A" but should read "appendix B." The commenter also pointed out that there is no
Sec. 63.9345(f) as referenced in Sec. 63.9330(b). The reference should be Sec. 63.9345(c).
Response: We acknowledge both of the typographical errors in the proposed rule identified by
the commenter. The reference to 63.9345(f) has been corrected in the final rule to read 63.9345(c).
2.12.2 Comment: One commenter (TV-D-04) requested clarification on the text addressing
"the non-air health, environmental and energy impacts" where reference is made to "... a very small
increase in fuel consumption resulting from back pressure caused by the emission control system." The
commenter asked what the effects on the actual emissions are and how this will affect emissions
estimates and engine certification?
Response: The effects on actual emissions caused by the add-on control device are
insignificant and do not affect emissions estimates.
2.12.3 Comment: Two commenters (TV-D-12 and IV-D-16) pointed out an inconsistency
between the statement in the preamble that the typical air flow from a cell/stand used to test the typical
automobile engine is 500 dscfhn (67 Federal Register at 34552) and the statement in the memorandum
"Model Plants and HAP Emission Factors" from Icenhour and Clapsaddle (Midwest Research
Institute) to Pagan (EPA), February 14,2001 (H-B-7), that the typical air flow from such a unit is
500 acfm.
2-41
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Response: We agree with the commenter and acknowledge the typographical error in the
proposed rule preamble. The typical air flow from a cell/stand used to test the typical automobile
engine is approximately 500 acfrn.
2.12.4 Comment: One commenter (IV-D-01) informed us that two of the ASTM standards
referenced in the proposed rule have been updated: D 3154-91 (1995) is now D 3154-00, and
D 5835-95 is now D 5835-95 (2001).
Response: We acknowledge and appreciate the updated information provided by the
commenter. These test methods were discussed in the preamble of the rule as potential alternate test
methods (with regard to voluntary consensus standards review), however, were determined to be
inappropriate for this rule.
2.12.5 Comment: One commenter (TV-D-15) had a specific question concerning the data
used in the MACT floor determination involving Briggs & Stratton engine test cells used for testing
engines between 25 hp and 50 hp. The commenter stated, 'Table 1 of the Access database lists 70
test cells that are equal to or between 25 hp and 50 hp, but at least 43 of those test cells were not
included in the MACT database for the 25 hp and greater subcategory. Those 43 test cells are at
Briggs & Stratton facilities (ETF0009), but no Briggs & Stratton facility is included in the table of
MACT floor facilities with test cells used for testing engines with 25 hp or more. See Memorandum for
Icenhour to Pagan, "MACT floors and Above the Floor Options for the Engine Test Cells/Stands
NESHAP," February 14,2001, Table 3 (II-B-8).
Response: Table 1 of the MACT database shows the capacity of the individual engine test
cell/stand, not the actual size of engine that is tested in the test cell/stand. Table 2 of the MACT
database shows the actual size of the engine tested in the test cell/stand at the specific facility (as
reported in the facility's ICR response). Although the test cells at this Briggs & Stratton have the
capacity to test engines greater than 25 hp, the largest engine size actually tested was 22 hp.
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TECHNICAL REPORT DATA
(Please read Instructions on reverse before completing)
1 REPORT NO 2
EPA 453/R-03-001
4 TITLE AND SUBTITLE
National Emission Standards for Hazardous Air Poll
dllglllC 1CSI V_/C11&/OU1I1U?> D
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EPA Form 2220-1 (Rev. 4-77) PREVIOUS EDITION IS OBSOLETE
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United States Office of Air Quality Planning and Standards Publication No. EPA 4S3/R-03-001
Environmental Protection Air Quality Strategies and Standards Division February 2003
Agency Research Triangle Park, NC
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