US EPA proposes exemption of 3 hydrocarbons from venting prohibition

The United States Environmental Protection Agency (US EPA) has published a proposed rule that would lift the venting prohibition of three hydrocarbons used as substitutes in domestic and stand-alone retail refrigeration, which were previously approved under the Significant New Alternatives Policy (SNAP) Program. Written comments on the proposed rule shall be sent to the EPA by 11 June 2013.

The EPA is proposing to exempt from the venting prohibition hydrocarbons listed as “acceptable” or “acceptable under use conditions” under the SNAP Program in December 2011:

Isobutane (R600a) and R441A, which were listed as acceptable, subject to use conditions, as refrigerant substitutes in household refrigerators, freezers, and combination refrigerators and freezers, and
Propane (R290), which was listed as acceptable, subject to use conditions, as a refrigerant substitute in stand-alone retail food refrigerators and freezers.

The proposed exemption could facilitate a wider uptake of the three hydrocarbons in these specific uses in the US.

Negligible environmental impact

The Clean Air Act prohibits venting of ozone-depleting substances or their substitutes, including hydrofluorocarbons (HFCs) and natural refrigerants. Nevertheless, certain substitute refrigerants in specific end-uses might be exempt if the EPA determines venting, release, or disposal of these refrigerants do not pose a threat to the environment.

Based on an analysis of inherent characteristics of the three hydrocarbons, as well as an assessment of the effects of their venting, release, or disposal related to the specific end-uses, the EPA “concludes that these three hydrocarbon refrigerants are not expected to pose a significant threat to the environment”, reads the proposed rule. In addition to their very low global warming potential (GWP) and zero ozone depleting potential (ODP), hydrocarbons have very short atmospheric lifetime (7-8 days) and after release they break down into naturally occurring compounds. “

Existing exemptions from venting prohibition

Several exemptions from the venting prohibition are already in place, including:

Hydrocarbons in processing of hydrocarbons
Ammonia in commercial refrigeration, absorption chillers
CO₂ in any application
Water in any application

Comments welcome until 11 June 2013

The EPA is taking comments to the proposed rule until 11 June 2013. More information on the proposed rule and how to submit the comments could be found here.