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Title 40

Displaying title 40, up to date as of 8/13/2026. Title 40 was last amended 8/13/2026.
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Definitions

§ 60.4248 What definitions apply to this subpart?

As used in this subpart, all terms not defined herein shall have the meaning given them in the CAA and in subpart A of this part.

Certified emissions life means the period during which the engine is designed to properly function in terms of reliability and fuel consumption, without being remanufactured, specified as a number of hours of operation or calendar years, whichever comes first. The values for certified emissions life for stationary SI ICE with a maximum engine power less than or equal to 19 KW (25 HP) are given in 40 CFR 1054.107 and 1060.101, as appropriate. The values for certified emissions life for stationary SI ICE with a maximum engine power greater than 19 KW (25 HP) certified to 40 CFR part 1048 are given in 40 CFR 1048.101(g). The certified emissions life for stationary SI ICE with a maximum engine power greater than 75 KW (100 HP) certified under the voluntary manufacturer certification program of this subpart is 5,000 hours or 7 years, whichever comes first. You may request in your application for certification that we approve a shorter certified emissions life for an engine family. We may approve a shorter certified emissions life, in hours of engine operation but not in years, if we determine that these engines will rarely operate longer than the shorter certified emissions life. If engines identical to those in the engine family have already been produced and are in use, your demonstration must include documentation from such in-use engines. In other cases, your demonstration must include an engineering analysis of information equivalent to such in-use data, such as data from research engines or similar engine models that are already in production. Your demonstration must also include any overhaul interval that you recommend, any mechanical warranty that you offer for the engine or its components, and any relevant customer design specifications. Your demonstration may include any other relevant information. The certified emissions life value may not be shorter than any of the following:

(1) 1,000 hours of operation.

(2) Your recommended overhaul interval.

(3) Your mechanical warranty for the engine.

Certified stationary internal combustion engine means an engine that belongs to an engine family that has a certificate of conformity that complies with the emission standards and requirements in this part, or of 40 CFR part 1048 or 1054, as appropriate.

Combustion turbine means all equipment, including but not limited to the turbine, the fuel, air, lubrication and exhaust gas systems, control systems (except emissions control equipment), and any ancillary components and sub-components comprising any simple cycle combustion turbine, any regenerative/recuperative cycle combustion turbine, the combustion turbine portion of any cogeneration cycle combustion system, or the combustion turbine portion of any combined cycle steam/electric generating system.

Compression ignition means relating to a type of stationary internal combustion engine that is not a spark ignition engine.

Date of manufacture means one of the following things:

(1) For freshly manufactured engines and modified engines, date of manufacture means the date the engine is originally produced.

(2) For reconstructed engines, date of manufacture means the date the engine was originally produced, except as specified in paragraph (3) of this definition.

(3) Reconstructed engines are assigned a new date of manufacture if the fixed capital cost of the new and refurbished components exceeds 75 percent of the fixed capital cost of a comparable entirely new facility. An engine that is produced from a previously used engine block does not retain the date of manufacture of the engine in which the engine block was previously used if the engine is produced using all new components except for the engine block. In these cases, the date of manufacture is the date of reconstruction or the date the new engine is produced.

Diesel fuel means any liquid obtained from the distillation of petroleum with a boiling point of approximately 150 to 360 degrees Celsius. One commonly used form is number 2 distillate oil.

Digester gas means any gaseous by-product of wastewater treatment typically formed through the anaerobic decomposition of organic waste materials and composed principally of methane and carbon dioxide (CO2).

Emergency stationary internal combustion engine means any stationary reciprocating internal combustion engine that meets all of the criteria in paragraphs (1) through (3) of this definition. All emergency stationary ICE must comply with the requirements specified in § 60.4243(d) in order to be considered emergency stationary ICE. If the engine does not comply with the requirements specified in § 60.4243(d), then it is not considered to be an emergency stationary ICE under this subpart.

(1) The stationary ICE is operated to provide electrical power or mechanical work during an emergency situation. Examples include stationary ICE used to produce power for critical networks or equipment (including power supplied to portions of a facility) when electric power from the local utility (or the normal power source, if the facility runs on its own power production) is interrupted, or stationary ICE used to pump water in the case of fire or flood, etc.

(2) The stationary ICE is operated under limited circumstances for situations not included in paragraph (1) of this definition, as specified in § 60.4243(d).

(3) The stationary ICE operates as part of a financial arrangement with another entity in situations not included in paragraph (1) of this definition only as allowed in § 60.4243(d)(3)(i).

Engine manufacturer means the manufacturer of the engine. See the definition of “manufacturer” in this section.

Four-stroke engine means any type of engine which completes the power cycle in two crankshaft revolutions, with intake and compression strokes in the first revolution and power and exhaust strokes in the second revolution.

Freshly manufactured engine means an engine that has not been placed into service. An engine becomes freshly manufactured when it is originally produced.

Gasoline means any fuel sold in any State for use in motor vehicles and motor vehicle engines, or nonroad or stationary engines, and commonly or commercially known or sold as gasoline.

Installed means the engine is placed and secured at the location where it is intended to be operated.

Landfill gas means a gaseous by-product of the land application of municipal refuse typically formed through the anaerobic decomposition of waste materials and composed principally of methane and CO2.

Lean burn engine means any two-stroke or four-stroke spark ignited engine that does not meet the definition of a rich burn engine.

Liquefied petroleum gas means any liquefied hydrocarbon gas obtained as a by-product in petroleum refining or natural gas production.

Manufacturer has the meaning given in section 216(1) of the Clean Air Act. In general, this term includes any person who manufactures a stationary engine for sale in the United States or otherwise introduces a new stationary engine into commerce in the United States. This includes importers who import stationary engines for resale.

Maximum engine power means maximum engine power as defined in 40 CFR 1048.801.

Model year means the calendar year in which an engine is manufactured (see “date of manufacture”), except as follows:

(1) Model year means the annual new model production period of the engine manufacturer in which an engine is manufactured (see “date of manufacture”), if the annual new model production period is different than the calendar year and includes January 1 of the calendar year for which the model year is named. It may not begin before January 2 of the previous calendar year and it must end by December 31 of the named calendar year.

(2) For an engine that is converted to a stationary engine after being placed into service as a nonroad or other non-stationary engine, model year means the calendar year or new model production period in which the engine was manufactured (see “date of manufacture”).

Natural gas means a naturally occurring mixture of hydrocarbon and non-hydrocarbon gases found in geologic formations beneath the Earth's surface, of which the principal constituent is methane. Natural gas may be field or pipeline quality.

Other internal combustion engine means any internal combustion engine, except combustion turbines, which is not a reciprocating internal combustion engine or rotary internal combustion engine.

Pipeline-quality natural gas means a naturally occurring fluid mixture of hydrocarbons (e.g., methane, ethane, or propane) produced in geological formations beneath the Earth's surface that maintains a gaseous state at standard atmospheric temperature and pressure under ordinary conditions, and which is provided by a supplier through a pipeline. Pipeline-quality natural gas must either be composed of at least 70 percent methane by volume or have a gross calorific value between 950 and 1,100 British thermal units per standard cubic foot.

Rich burn engine means any four-stroke spark ignited engine where the manufacturer's recommended operating air/fuel ratio divided by the stoichiometric air/fuel ratio at full load conditions is less than or equal to 1.1. Engines originally manufactured as rich burn engines, but modified prior to June 12, 2006, with passive emission control technology for NOX (such as pre-combustion chambers) will be considered lean burn engines. Also, existing engines where there are no manufacturer's recommendations regarding air/fuel ratio will be considered a rich burn engine if the excess oxygen content of the exhaust at full load conditions is less than or equal to 2 percent.

Rotary internal combustion engine means any internal combustion engine which uses rotary motion to convert heat energy into mechanical work.

Spark ignition means relating to either: a gasoline-fueled engine; or any other type of engine with a spark plug (or other sparking device) and with operating characteristics significantly similar to the theoretical Otto combustion cycle. Spark ignition engines usually use a throttle to regulate intake air flow to control power during normal operation. Dual-fuel engines in which a liquid fuel (typically diesel fuel) is used for compression ignition and gaseous fuel (typically natural gas) is used as the primary fuel at an annual average ratio of less than 2 parts diesel fuel to 100 parts total fuel on an energy equivalent basis are spark ignition engines.

Stationary internal combustion engine means any internal combustion engine, except combustion turbines, that converts heat energy into mechanical work and is not mobile. Stationary ICE differ from mobile ICE in that a stationary internal combustion engine is not a nonroad engine as defined at 40 CFR 1068.30 (excluding paragraph (2)(ii) of that definition), and is not used to propel a motor vehicle, aircraft, or a vehicle used solely for competition. Stationary ICE include reciprocating ICE, rotary ICE, and other ICE, except combustion turbines.

Stationary internal combustion engine test cell/stand means an engine test cell/stand, as defined in 40 CFR part 63, subpart PPPPP, that tests stationary ICE.

Stoichiometric means the theoretical air-to-fuel ratio required for complete combustion.

Two-stroke engine means a type of engine which completes the power cycle in single crankshaft revolution by combining the intake and compression operations into one stroke and the power and exhaust operations into a second stroke. This system requires auxiliary scavenging and inherently runs lean of stoichiometric.

Volatile organic compounds means volatile organic compounds as defined in 40 CFR 51.100(s).

Voluntary certification program means an optional engine certification program that manufacturers of stationary SI internal combustion engines with a maximum engine power greater than 19 KW (25 HP) that do not use gasoline and are not rich burn engines that use LPG can choose to participate in to certify their engines to the emission standards in § 60.4231(d) or (e), as applicable.

[73 FR 3591, Jan. 18, 2008, as amended at 73 FR 59177, Oct. 8, 2008; 76 FR 37974, June 28, 2011; 78 FR 6698, Jan. 30, 2013; 86 FR 34363, June 29, 2021; 87 FR 48606, Aug. 10, 2022]

Table 1 to Subpart JJJJ of Part 60—NOX, CO, and VOC Emission Standards for Stationary Non-Emergency SI Engines ≥100 HP (Except Gasoline and Rich Burn LPG), Stationary SI Landfill/Digester Gas Engines, and Stationary Emergency Engines >25 HP

Engine type
and fuel
Maximum
engine power
Manufacture
date
Emission standards a
g/HP-hr ppmvd at 15% O2
NOX CO VOC d NOX CO VOC d
Non-Emergency SI Natural Gas b and Non-Emergency SI Lean Burn LPG b 100≤HP<500 7/1/2008 2.0 4.0 1.0 160 540 86
1/1/2011 1.0 2.0 0.7 82 270 60
Non-Emergency SI Lean Burn Natural Gas and LPG 500≤HP<1,350 1/1/2008 2.0 4.0 1.0 160 540 86
7/1/2010 1.0 2.0 0.7 82 270 60
Non-Emergency SI Natural Gas and Non-Emergency SI Lean Burn LPG (except lean burn 500≤HP<1,350) HP≥500 7/1/2007 2.0 4.0 1.0 160 540 86
HP≥500 7/1/2010 1.0 2.0 0.7 82 270 60
Landfill/Digester Gas (except lean burn 500≤HP<1,350) HP<500 7/1/2008 3.0 5.0 1.0 220 610 80
1/1/2011 2.0 5.0 1.0 150 610 80
HP≥500 7/1/2007 3.0 5.0 1.0 220 610 80
7/1/2010 2.0 5.0 1.0 150 610 80
Landfill/Digester Gas Lean Burn 500≤HP<1,350 1/1/2008 3.0 5.0 1.0 220 610 80
7/1/2010 2.0 5.0 1.0 150 610 80
Emergency 25<HP<130 1/1/2009 c 10 387 N/A N/A N/A N/A
HP≥130 2.0 4.0 1.0 160 540 86
a Owners and operators of stationary non-certified SI engines may choose to comply with the emission standards in units of either g/HP-hr or ppmvd at 15 percent O2.
b Owners and operators of new or reconstructed non-emergency lean burn SI stationary engines with a site rating of greater than or equal to 250 brake HP located at a major source that are meeting the requirements of 40 CFR part 63, subpart ZZZZ, Table 2a do not have to comply with the CO emission standards of Table 1 of this subpart.
c The emission standards applicable to emergency engines between 25 HP and 130 HP are in terms of NOX + HC.
d For purposes of this subpart, when calculating emissions of volatile organic compounds, emissions of formaldehyde should not be included.

[76 FR 37975, June 28, 2011]

Table 2 to Subpart JJJJ of Part 60—Requirements for Performance Tests

As stated in § 60.4244, you must comply with the following requirements for performance tests within 10 percent of 100 percent peak (or the highest achievable) load].

For each Complying with the
requirement to
You must Using According to the following
requirements
1. Stationary SI internal combustion engine demonstrating compliance according to § 60.4244 a. Limit the concentration of NOX in the stationary SI internal combustion engine exhaust i. Select the sampling port location and the number/location of traverse points at the exhaust of the stationary internal combustion engine; (1) Method 1 or 1A of 40 CFR part 60, appendix A-1, if measuring flow rate (a) Alternatively, for NOX, O2, and moisture measurement, ducts ≤6 inches in diameter may be sampled at a single point located at the duct centroid and ducts >6 and ≤12 inches in diameter may be sampled at 3 traverse points located at 16.7, 50.0, and 83.3% of the measurement line (`3-point long line'). If the duct is >12 inches in diameter and the sampling port location meets the two and half-diameter criterion of Section 11.1.1 of Method 1 of 40 CFR part 60, Appendix A, the duct may be sampled at `3-point long line'; otherwise, conduct the stratification testing and select sampling points according to Section 8.1.2 of Method 7E of 40 CFR part 60, Appendix A.
ii. Determine the O2 concentration of the stationary internal combustion engine exhaust at the sampling port location; (2) Method 3, 3A, or 3B b of 40 CFR part 60, appendix A-2 or ASTM Method D6522-00 (Reapproved 2005) a d (b) Measurements to determine O2 concentration must be made at the same time as the measurements for NOX concentration.
iii. If necessary, determine the exhaust flowrate of the stationary internal combustion engine exhaust; (3) Method 2 or 2C of 40 CFR part 60, appendix A-1 or Method 19 of 40 CFR part 60, appendix A-7 (c) Measurements to determine the exhaust flowrate must be made (1) at the same time as the measurement for NOX concentration or, alternatively (2) according to the option in Section 11.1.2 of Method 1A of 40 CFR part 60, Appendix A-1, if applicable.
iv. If necessary, measure moisture content of the stationary internal combustion engine exhaust at the sampling port location; and (4) Method 4 of 40 CFR part 60, appendix A-3, Method 320 of 40 CFR part 63, appendix A,e or ASTM Method D6348-03 d e (d) Measurements to determine moisture must be made at the same time as the measurement for NOX concentration.
v. Measure NOX at the exhaust of the stationary internal combustion engine; if using a control device, the sampling site must be located at the outlet of the control device (5) Method 7E of 40 CFR part 60, appendix A-4, ASTM Method D6522-00 (Reapproved 2005),a d Method 320 of 40 CFR part 63, appendix A,e or ASTM Method D6348-03 d e (e) Results of this test consist of the average of the three 1-hour or longer runs.
b. Limit the concentration of CO in the stationary SI internal combustion engine exhaust i. Select the sampling port location and the number/location of traverse points at the exhaust of the stationary internal combustion engine; (1) Method 1 or 1A of 40 CFR part 60, appendix A-1, if measuring flow rate (a) Alternatively, for CO, O2, and moisture measurement, ducts ≤6 inches in diameter may be sampled at a single point located at the duct centroid and ducts >6 and ≤12 inches in diameter may be sampled at 3 traverse points located at 16.7, 50.0, and 83.3% of the measurement line (`3-point long line'). If the duct is >12 inches in diameter and the sampling port location meets the two and half-diameter criterion of Section 11.1.1 of Method 1 of 40 CFR part 60, Appendix A, the duct may be sampled at `3-point long line'; otherwise, conduct the stratification testing and select sampling points according to Section 8.1.2 of Method 7E of 40 CFR part 60, Appendix A.
ii. Determine the O2 concentration of the stationary internal combustion engine exhaust at the sampling port location; (2) Method 3, 3A, or 3B b of 40 CFR part 60, appendix A-2 or ASTM Method D6522-00 (Reapproved 2005) a d (b) Measurements to determine O2 concentration must be made at the same time as the measurements for CO concentration.
iii. If necessary, determine the exhaust flowrate of the stationary internal combustion engine exhaust; (3) Method 2 or 2C of 40 CFR 60, appendix A-1 or Method 19 of 40 CFR part 60, appendix A-7 (c) Measurements to determine the exhaust flowrate must be made (1) at the same time as the measurement for CO concentration or, alternatively (2) according to the option in Section 11.1.2 of Method 1A of 40 CFR part 60, Appendix A-1, if applicable.
iv. If necessary, measure moisture content of the stationary internal combustion engine exhaust at the sampling port location; and (4) Method 4 of 40 CFR part 60, appendix A-3, Method 320 of 40 CFR part 63, appendix A,e or ASTM Method D6348-03 d e (d) Measurements to determine moisture must be made at the same time as the measurement for CO concentration.
v. Measure CO at the exhaust of the stationary internal combustion engine; if using a control device, the sampling site must be located at the outlet of the control device (5) Method 10 of 40 CFR part 60, appendix A4, ASTM Method D6522-00 (Reapproved 2005),a d e Method 320 of 40 CFR part 63, appendix A,e or ASTM Method D6348-03 d e (e) Results of this test consist of the average of the three 1-hour or longer runs.
c. Limit the concentration of VOC in the stationary SI internal combustion engine exhaust i. Select the sampling port location and the number/location of traverse points at the exhaust of the stationary internal combustion engine; (1) Method 1 or 1A of 40 CFR part 60, appendix A-1, if measuring flow rate (a) Alternatively, for VOC, O2, and moisture measurement, ducts ≤6 inches in diameter may be sampled at a single point located at the duct centroid and ducts >6 and ≤12 inches in diameter may be sampled at 3 traverse points located at 16.7, 50.0, and 83.3% of the measurement line (`3-point long line'). If the duct is >12 inches in diameter and the sampling port location meets the two and half-diameter criterion of Section 11.1.1 of Method 1 of 40 CFR part 60, Appendix A, the duct may be sampled at `3-point long line'; otherwise, conduct the stratification testing and select sampling points according to Section 8.1.2 of Method 7E of 40 CFR part 60, Appendix A.
ii. Determine the O2 concentration of the stationary internal combustion engine exhaust at the sampling port location; (2) Method 3, 3A, or 3B b of 40 CFR part 60, appendix A-2 or ASTM Method D6522-00 (Reapproved 2005) a d (b) Measurements to determine O2 concentration must be made at the same time as the measurements for VOC concentration.
iii. If necessary, determine the exhaust flowrate of the stationary internal combustion engine exhaust; (3) Method 2 or 2C of 40 CFR 60, appendix A-1 or Method 19 of 40 CFR part 60, appendix A-7 (c) Measurements to determine the exhaust flowrate must be made (1) at the same time as the measurement for VOC concentration or, alternatively (2) according to the option in Section 11.1.2 of Method 1A of 40 CFR part 60, Appendix A-1, if applicable.
iv. If necessary, measure moisture content of the stationary internal combustion engine exhaust at the sampling port location; and (4) Method 4 of 40 CFR part 60, appendix A-3, Method 320 of 40 CFR part 63, appendix A,e or ASTM Method D6348-03 d e (d) Measurements to determine moisture must be made at the same time as the measurement for VOC concentration.
v. Measure VOC at the exhaust of the stationary internal combustion engine; if using a control device, the sampling site must be located at the outlet of the control device (5) Methods 25A and 18 of 40 CFR part 60, appendices A-6 and A-7, Method 25A with the use of a hydrocarbon cutter as described in 40 CFR 1065.265, Method 18 of 40 CFR part 60, appendix A-6,c e Method 320 of 40 CFR part 63, appendix A,e or ASTM Method D6348-03 d e (e) Results of this test consist of the average of the three 1-hour or longer runs.
a Also, you may petition the Administrator for approval to use alternative methods for portable analyzer.
b You may use ASME PTC 19.10-1981, Flue and Exhaust Gas Analyses, for measuring the O2 content of the exhaust gas as an alternative to EPA Method 3B. AMSE PTC 19.10-1981 incorporated by reference, see 40 CFR 60.17
c You may use EPA Method 18 of 40 CFR part 60, appendix A-6, provided that you conduct an adequate pre-survey test prior to the emissions test, such as the one described in OTM 11 on EPA's website (http://www.epa.gov/ttn/emc/prelim/otm11.pdf).
d Incorporated by reference; see 40 CFR 60.17.
e You must meet the requirements in § 60.4245(d).

[85 FR 63408, Oct. 7, 2020]

Table 3 to Subpart JJJJ of Part 60—Applicability of General Provisions to Subpart JJJJ

[As stated in § 60.4246, you must comply with the following applicable General Provisions]

General provisions citation Subject of citation Applies to subpart Explanation
§ 60.1 General applicability of the General Provisions Yes
§ 60.2 Definitions Yes Additional terms defined in § 60.4248.
§ 60.3 Units and abbreviations Yes
§ 60.4 Address Yes
§ 60.5 Determination of construction or modification Yes
§ 60.6 Review of plans Yes
§ 60.7 Notification and Recordkeeping Yes Except that § 60.7 only applies as specified in § 60.4245.
§ 60.8 Performance tests Yes Except that § 60.8 only applies to owners and operators who are subject to performance testing in subpart JJJJ.
§ 60.9 Availability of information Yes
§ 60.10 State Authority Yes
§ 60.11 Compliance with standards and maintenance requirements Yes Requirements are specified in subpart JJJJ.
§ 60.12 Circumvention Yes
§ 60.13 Monitoring requirements No
§ 60.14 Modification Yes
§ 60.15 Reconstruction Yes
§ 60.16 Priority list Yes
§ 60.17 Incorporations by reference Yes
§ 60.18 General control device requirements No
§ 60.19 General notification and reporting requirements Yes

Table 4 to Subpart JJJJ of Part 60—Applicability of Mobile Source Provisions for Manufacturers Participating in the Voluntary Certification Program and Certifying Stationary SI ICE to Emission Standards in Table 1 of Subpart JJJJ

[As stated in § 60.4247, you must comply with the following applicable mobile source provisions if you are a manufacturer participating in the voluntary certification program and certifying stationary SI ICE to emission standards in Table 1 of subpart JJJJ]

Mobile source provisions citation Subject of citation Applies to subpart Explanation
1048 subpart A Overview and Applicability Yes
1048 subpart B Emission Standards and Related Requirements Yes Except for the specific sections below.
1048.101 Exhaust Emission Standards No
1048.105 Evaporative Emission Standards No
1048.110 Diagnosing Malfunctions No
1048.140 Certifying Blue Sky Series Engines No
1048.145 Interim Provisions No
1048 subpart C Certifying Engine Families Yes Except for the specific sections below.
1048.205(b) AECD reporting Yes
1048.205(c) OBD Requirements No
1048.205(n) Deterioration Factors Yes Except as indicated in 60.4247(c).
1048.205(p)(1) Deterioration Factor Discussion Yes
1048.205(p)(2) Liquid Fuels as they require No
1048.240(b)(c)(d) Deterioration Factors Yes
1048 subpart D Testing Production-Line Engines Yes
1048 subpart E Testing In-Use Engines No
1048 subpart F Test Procedures Yes
1065.5(a)(4) Raw sampling (refers reader back to the specific emissions regulation for guidance) Yes
1048 subpart G Compliance Provisions Yes
1048 subpart H Reserved
1048 subpart I Definitions and Other Reference Information Yes
1048 appendix I and II Yes
1065 (all subparts) Engine Testing Procedures Yes Except for the specific section below.
1065.715 Test Fuel Specifications for Natural Gas No
1068 (all subparts) General Compliance Provisions for Nonroad Programs Yes Except for the specific sections below.
1068.245 Hardship Provisions for Unusual Circumstances No
1068.250 Hardship Provisions for Small-Volume Manufacturers No
1068.255 Hardship Provisions for Equipment Manufacturers and Secondary Engine Manufacturers No