Background Information

The proposed standard, IIAR HC (IIAR HC-202x), is intended for providing the minimum requirements for design, installation, startup, as well as inspection, testing, and maintenance (ITM) tasks, decommissioning, and general safety requirements applicable to closed-circuit refrigeration systems utilizing hydrocarbon refrigerants. This standard specifically applies to Propane (R290), N-Butane (R600), and Isobutane (R600a) as natural hydrocarbon refrigerants with zero (0) ozone depleting potential (ODP) and extremely low global warming potential (GWP). This proposed standard reflects the input received and consensus thereof from the refrigeration industry practitioners for hydrocarbon refrigeration system minimum requirements. This standard is intended to apply to natural hydrocarbon refrigeration systems, devices, and/or components that are not regulated by listing agencies. This proposed standard is not intended to serve as a comprehensive, detailed technical manual and shall not be used as such.

This proposed standard defines minimum safe requirements for general and specific design, installation, startup, and inspection, testing, and maintenance (ITM) tasks applicable to stationary closed-circuit refrigeration system utilizing hydrocarbon refrigerants. It also defines minimum decommissioning (permanently retiring) requirements and general safety requirements. Additional precautions may be necessary because of particular circumstances, project specifications, or other jurisdictional considerations.

This proposed standard is directed towards the safety of persons and property on or near the premises where the stationary refrigeration systems are located. It supplements existing general refrigeration standards issued by IIAR and other organizations such as ASHRAE, ASME, and ANSI. It is not intended to supplant existing safety codes (e.g., model mechanical or fire codes).

This proposed standard has been approved by the IIAR HC Subcommittee, IIAR's Standard Committee, and IIAR’s Board of Directors for public review.

This fifth (5th) public review of the proposed standard will be conducted from August 28th, 2026 through September 27th, 2026. Comments must be submitted to IIAR no later than 5:00 pm Eastern Standard Time (EST) on September 27th, 2026. Click here for a copy of the public review draft in electronic (pdf) form.

Copies will also be provided by fax or mailed upon request. Click here for the on-line request form, or click here to download a pdf file of the request form.

American National Standards Institute (ANSI) procedures will be utilized to develop evidence of consensus for this proposed standard. IIAR is the ANSI-Accredited standards developer for IIAR HC. Individuals, organizations, companies, government agencies, standards developers, etc., who are directly and materially affected by the proposed standard are invited to participate in the public review.

Letter to IIAR Members | Background Information | Public Review Announcement
Public Review Draft | Online Comment Form