Engine Testing Regulations
EPA has adopted emission standards for almost every kind of engine, including everything from lawn mowers to cruise ships. To show compliance with these emission standards, engine manufacturers must follow test procedures specified in the Code of Federal Regulations. This page provides links to the appropriate regulatory citations and includes published information related to the test procedures. These links include a general set of instructions and requirements for manufacturers to measure emissions for certifying their engines to EPA emission standards. Manufacturers should also read the regulations for category-specific provisions that apply.
The test procedures referenced on this page are related to engine-based exhaust emission standards. All types of engines are subject to the procedures in 40 CFR part 1065, excluding aircraft engines and those that require vehicle testing, though these procedures continue to be optional during a transition period for some engines.
IMPORTANT NOTE: When EPA makes changes to Part 1065 test procedures, manufacturers that are already subject to testing under Part 1065 may take up to 12 months to comply with the new specifications.
- Resource Information: Plain Language Format of Emission Regulations for Nonroad Engines (PDF)(6 pp, 243K, EPA-420-F-12-054, August 2012).
The following table shows which engine test procedures apply for each engine category. For ease of use, Electronic Code of Federal Regulations (e-CFR) links are provided.
|Vehicle Category Description
|Corresponding Regulation Page
|Corresponding e-CFR Link(s)
|Heavy-Duty Highway Engines
|Regulations for emissions from commercial trucks and buses (heavy-duty)
|Regulations for emissions from locomotives
|Marine Diesel Engines (Diesel Boats and Ships)
|Regulations for emissions from marine vessels with compression-ignition (diesel) engines
|Other Nonroad and Stationary Diesel Engines
|Regulations for emissions from heavy equipment with compression-ignition (diesel) engines
|Recreational Vehicles (Snowmobiles and some Dirt Bikes and ATVs)
|Regulations for emissions from recreational vehicles
|Marine Spark-Ignition Engines (Gasoline Boats and Personal Watercraft)
|Regulations for emissions from marine vessels with spark-ignition engines
|Other Nonroad and Stationary Spark-Ignition Engines at or below 19kW (Lawn and Garden)
|Regulations for emissions from small equipment and tools
|Other Nonroad and Stationary Spark-Ignition Engines above 19 kW (Forklifts, Generators and Compressors)
|Regulations for emissions from heavy equipment with spark-ignition engines
40 CFR part 1065 provides regulations for the required testing procedures for engines. The following list of regulations shows all the changes made to part 1065.
- Regulatory impact analyses;
- Comment summaries;
- Rule histories (including proposed rules); and/or
- Fact sheets.
NOTE: Rule-related materials vary by rule.