In the first action of its kind, the EPA is folding its Significant New Alternatives Policy (SNAP) for refrigerants into President Obama’s Climate Action Plan by proposing acceptable alternatives with low global warming potential (GWP) for use in six refrigeration and air-conditioning applications. The proposed refrigerants include one hydrofluorocarbon (HFC)—HFC-32—and four hydrocarbons—ethane, isobutane, propane, and R-441A.

The proposal would also exempt the proposed refrigerant substitutes from CAA Section 608’s prohibition on venting, release, or disposal because such releases do not pose a threat to the environment, says the EPA.

Low GWP

Developed by the EPA as required by Clean Air Act (CAA) Section 612, the SNAP program approves alternatives to commercial chemicals that destroy the earth’s protective ozone layer.  But some of the approved alternatives have significant GWP, and the EPA has modified the SNAP process to give closer consideration to alternatives with low GWP.

Hydrocarbon refrigerants have zero ozone-depleting potential and very low GWP potential, but because of high flammability factors, their use has been restricted to industrial applications.  EPA’s proposal would remove the restriction to allow their application in residential and commercial equipment subject to use requirements to reduce the risk of fires.  HFC-32 has about one-third the GWP of other hydrofluorocarbon refrigerants and a lower flammability than hydrocarbons.

Proposed uses

The proposed SNAP approvals are as follows:

• Ethane in very low temperature refrigeration and in nonmechanical heat transfer;
• Isobutane in retail food refrigeration (stand-alone commercial refrigerators and freezers) and in vending machines;
• Propane in household refrigerators, freezers, or combination refrigerators and freezers; in vending machines; and in room air conditioning units;
• The hydrocarbon blend R-441A in retail food refrigeration (stand-alone commercial refrigerators and freezers), in vending machines, and in room air conditioning units; and
• HFC-32 (difluoromethane) in room air conditioning units.

The EPA notes that hydrocarbon refrigerants have been in use in household and commercial refrigerators and freezers for over 15 years in countries such as Germany, the United Kingdom, Australia, and Japan.  To a lesser extent, hydrocarbon refrigerants have also been used internationally in small AC units such as mini-splits and portable room air conditioners.  Mini-split systems using HFC-32 are now being sold in Japan and are being introduced in India and Indonesia.

Use conditions

The proposed use conditions include limits on charge size as well as requirements for warnings and markings on equipment to inform consumers and technicians of potential flammability hazards.  The EPA is also proposing that the flammable refrigerants be limited for use only in new equipment that has been designed and manufactured specifically for use with the listed alternative refrigerant.

Regarding the proposed removal of the prohibition on venting, release, or disposal for the four hydrocarbon refrigerant substitutes, the EPA notes that other environmental regulatory requirements still apply.  For example, isobutane, propane, and R-441A are volatile organic compounds (VOCs) that may become subject to state plans and control strategies to attain or maintain the National Ambient Air Quality Standard (NAAQS) for ozone.

Proposal to add substances to the SNAP list