U.S. Code of Federal Regulations
Regulations most recently checked for updates: Jul 10, 2020
The exhaust emission standards of this section apply after the 2014 model year. Certain of these standards also apply for model year 2014 and earlier. This section presents the full set of emission standards that apply after all the transition and phase-in provisions of § 1039.102 and § 1039.104 expire. See § 1039.102 and 40 CFR 89.112 for exhaust emission standards that apply to 2014 and earlier model years. Section 1039.105 specifies smoke standards.
(a) Emission standards for transient testing. Transient exhaust emissions from your engines may not exceed the applicable emission standards in Table 1 of this section. Measure emissions using the applicable transient test procedures described in subpart F of this part. The following engines are not subject to the transient standards in this paragraph (a):
(1) Engines above 560 kW.
(2) Constant-speed engines.
(b) Emission standards for steady-state testing. Steady-state exhaust emissions from your engines may not exceed the applicable emission standards in Table 1 of this section. Measure emissions using the applicable steady-state test procedures described in subpart F of this part.
Table 1 of § 1039.101 - Tier 4 Exhaust Emission Standards After the 2014 Model Year, g/kW-hr 1
|Maximum engine power||Application||PM||NO||NMHC||NO||CO|
|kW <19||All||2 0.40||7.5||3 6.6|
|19 ≤kW <56||All||0.03||4.7||4 5.0|
|56 ≤kW <130||All||0.02||0.40||0.19||5.0|
|130 ≤kW ≤560||All||0.02||0.40||0.19||3.5|
|kW >560||All except generator sets||0.04||3.5||0.19||3.5|
1 Note that some of these standards also apply for 2014 and earlier model years. This table presents the full set of emission standards that apply after all the transition and phase-in provisions of § 1039.102 expire.
2 See paragraph (c) of this section for provisions related to an optional PM standard for certain engines below 8 kW.
3 The CO standard is 8.0 g/kW-hr for engines below 8 kW.
4 The CO standard is 5.5 g/kW-hr for engines below 37 kW.
(c) Optional PM standard for engines below 8 kW. You may certify hand-startable, air-cooled, direct injection engines below 8 kW to an optional Tier 4 PM standard of 0.60 g/kW-hr. The term hand-startable generally refers to engines that are started using a hand crank or pull cord. This PM standard applies to both steady-state and transient testing, as described in paragraphs (a) and (b) of this section. Engines certified under this paragraph (c) may not be used to generate PM or NO
(d) Averaging, banking, and trading. You may generate or use emission credits under the averaging, banking, and trading (ABT) program, as described in subpart H of this part. This requires that you specify a family emission limit (FEL) for each pollutant you include in the ABT program for each engine family. These FELs serve as the emission standards for the engine family with respect to all required testing instead of the standards specified in paragraphs (a) and (b) of this section. The FELs determine the not-to-exceed standards for your engine family, as specified in paragraph (e) of this section.
(1) Primary FEL caps. The FEL may not be higher than the limits in Table 2 of this section, except as allowed by paragraph (d)(2) of this section or by § 1039.102:
Table 2 of § 1039.101 - Tier 4 FEL Caps After the 2014 Model Year, g/kW-hr
|Maximum engine power||Application||PM||NO||NO|
|kW <19||All||0.80||1 9.5|
|19 ≤kW <56||All||0.05||7.5|
|56 ≤kW <130||All||0.04||0.80|
|130 ≤kW ≤560||All||0.04||0.80|
|kW >560||Generator sets||0.05||1.07|
|All except generator sets||0.07||6.2|
1 For engines below 8 kW, the FEL cap is 10.5 g/kW-hr for NO
(2) Alternate FEL caps. For a given power category, you may use the alternate FEL caps shown in Table 3 of this section instead of the FEL caps identified in paragraph (d)(1) of this section for up to 5 percent of your U.S.-directed production volume in a given model year.
Table 3 of § 1039.101 - Alternate FEL Caps, g/kW-hr
|Maximum engine power||Starting model year 1||PM FEL
|19 ≤kW <56||2 2016||0.30|
|56 ≤kW <130||2016||3 0.30||3 3.8|
|130 ≤kW ≤560||2015||0.20||3.8|
|kW >560||2019||0.10||4 3.5|
1 See § 1039.104(g) for alternate FEL caps that apply in earlier model years.
2 For manufacturers certifying engines under Option #1 of Table 3 of § 1039.102, these alternate FEL caps apply starting with the 2017 model year.
3 For engines below 75 kW, the FEL caps are 0.40 g/kW-hr for PM emissions and 4.4 g/kW-hr for NO
4 For engines above 560 kW, the provision for alternate NO
(e) Not-to-exceed standards. Exhaust emissions from your engines may not exceed the applicable not-to-exceed (NTE) standards in this paragraph (e).
(1) Measure emissions using the procedures described in subpart F of this part.
(2) Except as noted in paragraph (e)(7) of this section, the NTE standard, rounded to the same number of decimal places as the applicable standard in Table 1 of this section, is determined from the following equation:
(3) The NTE multiplier for each pollutant is 1.25, except in the following cases:
|If . . .||Or . . .||Then . . .|
|(i) The engine family is certified to a NO||The engine family is certified to a NO||The multiplier for NO|
|(ii) The engine family is certified to a PM standard less than 0.07 g/kW-hr without using ABT||The engine family is certified to a PM FEL less than 0.07 g/kW-hr||The multiplier for PM is 1.50.|
(4) There are two sets of specifications of ambient operating regions that will apply for all NTE testing of engines in an engine family. You must choose one set for each engine family and must identify your choice of ambient operating regions in each application for certification for an engine family. You may choose separately for each engine family. Choose one of the following ambient operating regions:
(i) All altitudes less than or equal to 5,500 feet above sea level during all ambient temperature and humidity conditions.
(ii) All altitudes less than or equal to 5,500 feet above sea level, for temperatures less than or equal to the temperature determined by the following equation at the specified altitude:
(5) Temperature and humidity ranges for which correction factors are allowed are specified in 40 CFR 86.1370-2007(e).
(i) If you choose the ambient operating region specified in paragraph (e)(4)(i) of this section, the temperature and humidity ranges for which correction factors are allowed are defined in 40 CFR 86.1370-2007(e)(1).
(ii) If you choose the ambient operating region specified in paragraph (e)(4)(ii) of this section, the temperature and humidity ranges for which correction factors are allowed are defined in 40 CFR 86.1370-2007(e)(2).
(6) For engines equipped with exhaust-gas recirculation, the NTE standards of this section do not apply during the cold operating conditions specified in 40 CFR 86.1370-2007(f).
(7) For engines certified to a PM FEL less than or equal to 0.01 g/kW-hr, the PM NTE standard is 0.02 g/kW-hr.
(f) Fuel types. The exhaust emission standards in this section apply for engines using the fuel type on which the engines in the engine family are designed to operate, except for engines certified under § 1039.615. For engines certified under § 1039.615, the standards of this section apply to emissions measured using the specified test fuel. You must meet the numerical emission standards for NMHC in this section based on the following types of hydrocarbon emissions for engines powered by the following fuels:
(1) Alcohol-fueled engines: THCE emissions.
(2) Gaseous-fueled engines: Nonmethane-nonethane hydrocarbon emissions.
(3) Other engines: NMHC emissions.
(g) Useful life. Your engines must meet the exhaust emission standards in paragraphs (a) through (e) of this section over their full useful life.
(1) The useful life values are shown in the following table, except as allowed by paragraph (g)(2) of this section:
Table 4 of § 1039.101 - Useful Life Values
|If your engine is certified as . . .||And its maximum power is . . .||And its rated speed is . . .||Then its useful life is . . .|
|(i) Variable speed or constant speed||kW <19||Any Speed||3,000 hours or five years, whichever comes first.|
|(ii) Constant speed||19 ≤kW <37||3,000 rpm or higher||3,000 hours or five years, whichever comes first.|
|(iii) Constant speed||19 ≤kW <37||Less than 3,000 rpm||5,000 hours or seven years, whichever comes first.|
|(iv) Variable||19 ≤kW <37||Any Speed||5,000 hours or seven years, whichever comes first.|
|(v) Variable speed or constant speed||kW ≥37||Any speed||8,000 hours or ten years, whichever comes first.|
(2) You may request in your application for certification that we approve a shorter useful life for an engine family. We may approve a shorter useful life, in hours of engine operation but not in years, if we determine that these engines will rarely operate longer than the shorter useful 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 useful life value may not be shorter than any of the following:
(i) 1,000 hours of operation.
(ii) Your recommended overhaul interval.
(iii) Your mechanical warranty for the engine.
(h) Applicability for testing. The emission standards in this subpart apply to all testing, including certification, selective enforcement audits, and in-use testing. For selective enforcement audits, we will require you to perform duty-cycle testing as specified in §§ 1039.505 and 1039.510. The NTE standards of this section apply for those tests. We will not direct you to do additional testing under a selective enforcement audit to show that your engines meet the NTE standards.