Aftermarket Conversion Systems: EPA Regulations & Guidance

EPA implements streamled rules for older conversion.
The U.S. Environmental Protection Agency requires that manufacturers of vehicles and engines that run on natural gas prove that these conversions meet the Clean Air Act emissions requirements, since it is against the law to tamper with emissions systems on vehicles if the result is greater emissions. Under the current regulation contained in 40 CFR 85 and 86, all natural gas powered vehicles and engines must have a Certificate of Conformity.

In March 2011, the U.S. Environmental Protection Agency issued new rules to streamline this process.

The changes in 40 C.F.R. Parts 85 and 86 would have the greatest impact on conversions of vehicles that are older than two years. The new program expands compliance options to include less burdensome demonstration requirements for vehicles that are two years or older. The revised regulations establish three new tiers for vehicles: relatively new vehicles; vehicles older than two years and vehicles beyond their useful life, which is different depending on the size and weight of the vehicle. The goal is to provide flexibility but to also sustain EPA's oversight and longstanding commitment to the environmental integrity of clean alternative fuel conversions.

Beyond Useful Life
EPA’s new rules provide different requirements for vehicles and engine depending on whether the vehicle or engine is still within its useful life or has exceeded the useful life period. All vehicles and engines, however, unless they predate EPA regulations and certification (1960’s) must go through EPA’s approval process. The useful life periods presented here for light duty vehicles are Tier 2 light duty vehicles, which have generally been in production since about 2004; Tier 1 and older vehicles were 100,000 miles/10 years.

• Light Duty Gasoline engines/vehicles: ≤ 8,500; 120,000 miles/10 years or optional 150,000 miles/15 years
• 2005 & Later Complete Heavy-Duty Spark-Ignition Vehicles ≤ 14,000: 110,000 miles/11 years
• 2004 & Later Light heavy-duty diesel engines: 8,500 < LHDDE < 19,500; 110,000 miles/10 years
• Medium heavy-duty diesel engines: 19,500 ≤ MHDDE ≤ 33,000, 185,000 miles/10 years
• 2004 – 2007 & Later Heavy heavy-duty diesel engines (including urban bus): HHDDE > 33,000; 435,000 miles/22,000 hours/10 years
• 2005 & Later Heavy Duty Spark-Ignition Engines > 14,000: 110,000 miles/10 years

The major difference with some of the earlier vehicles that pre-date the years provided above is that the useful life years was 8 years instead of 10, otherwise the mileage levels were the same with exception of light duty gasoline vehicles having a 100,000 mile useful life in earlier years.
For more detailed information: http://www.epa.gov/otaq/standards/

NGVAmerica supports the changes in the regulation to provide great flexibility

Click here to read NGVAmerica’s position on the final rule.

Click here for a link to the regulations.

Click here to read NGVAmerica oral comments presented during a public hearing on the regulation

Click here to read NGVAmerica’s written comments, filed July 23, 2010.

Anti-tampering Provisions & Policy Guidance
EPA's policy has always required that manufacturers of conversion equipment ensure that their systems do not degrade the emissions performance of motor vehicles. This policy directive was first set out in EPA's Mobile Source Enforcement Memorandum 1A. The policy is based on the Clean Air Act's prohibition against tampering with motor vehicle emissions. See section 203(a), 42 U.S.C. 7522(a). Section 203(a)

makes it illegal to install any component or part if it defeats or "render[s] inoperative any device or element of design installed" on a certified motor vehicle or engine. EPA's stated purpose in issuing Memorandum 1A was to "provide criteria by which dealers [and now conversion manufacturers] can determine in advance that certain of their acts do not constitute tampering." Memorandum 1A requires that manufacturers have a "reasonable basis" for believing that their equipment or actions will not increase emissions. Memorandum 1A initially indicated that a manufacturer could satisfy the "reasonable basis" requirement if "emissions tests . . . have been performed according to testing procedures prescribed in 40 C.F.R. section 85" and these tests show" that the act [e.g., conversion] does not cause similar vehicles or engines to fail to meet the applicable emission standards."

Compliance with the testing procedures outlined above initially was sufficient to ensure that a manufacturer would not be subjected to an enforcement action for tampering even if their actions result in increased emissions. Thus, compliance with Memorandum 1A acted to insulate the manufacture from tampering violations. However, compliance with Memorandum 1A never relieved the manufacture of responsibility for in-use emissions performance, durability, and compliance with useful-life emission standards.

Policy Change
In September of 1997, the US Environmental Protection Agency (EPA) issued an addendum to Memorandum 1A. The addendum altered EPA policy with respect to conversions by requiring that manufacturers start certifying their systems in order to protect themselves from tampering violations. Under this new guidance, the only way manufacturers can satisfy the " reasonable basis" test is full certification (either EPA or CARB). EPA's action was prompted by evidence it had collected that suggested that conversion systems were increasing vehicle emissions. The agency believed that the only way it could effectively ensure that conversions were not increasing vehicle emissions was to subject them to full certification.

Supporting Documents
EPA 2009 Guidance
2006 Guidance
EPA 2005 OBD Guidance

Other Sources
EPA site for conversions
EPA Enforcement Office