July 10, 2026
To: IIAR Members
Re: First (1st) Public Review of Standard BSR/IIAR 4-2026, Installation of Closed-Circuit Ammonia Refrigeration Systems

The first (1st) public review of draft standard IIAR 4-2026, Installation of Closed-Circuit Ammonia Refrigeration Systems is now open. Substantive changes resulting from this public review will also be provided for comment in a future public review if necessary.

IIAR 4 specifies criteria for the installation of closed-circuit ammonia refrigeration systems. It presupposes that the persons who use the document have a working knowledge of the functionality of ammonia refrigerating system(s) and basic ammonia refrigerating practices and principles. This standard is intended for those who are involved with the installation of closed-circuit ammonia refrigeration systems. This standard shall apply only to closed-circuit refrigeration systems utilizing ammonia as the refrigerant. It supplements existing general refrigeration standards issued by IIAR and other organizations such as ASME and ANSI. It is not intended to supplant existing safety codes (e.g., model mechanical or fire codes).

IIAR has designated the revised standard as BSR/IIAR 4-2026. Upon approval by the ANSI Board of Standards Review, the standard will receive a different name that reflects this approval date.

We invite you to participate in the first (1st) public review of BSR/IIAR 4-2026. IIAR will use the American National Standards Institute (ANSI) procedures to develop evidence of consensus among affected parties. ANSI's role in the revision process is to establish and enforce standards of openness, balance, due process and harmonization with other American and International Standards. IIAR is the ANSI-accredited standards developer for BSR/IIAR 4-2026, and is responsible for the technical content of the standard.

This site includes links to the following attachments:

The 45-day public review period will be from July 10th, 2026 to August 24th, 2026. Comments are due no later than 5:00 p.m. Eastern Standard Time (EST) on August 24th, 2026.

Thank you for your interest in the first (1st) public review of BSR/IIAR 4-2026, Installation of Closed-Circuit Ammonia Refrigeration Systems.