IIAR - International Institute of All-Natural Refrigeration

IIAR Releases Latest Version of IIAR 2 Safety Standard for Ammonia Refrigeration

Model code bodies defer to IIAR 2 for ammonia refrigeration safety.

The International Institute of Ammonia Refrigeration (IIAR), based in Alexandria, Virginia (U.S.) has announced the release of ANSI/IIAR 2-2021, the latest version of IIAR 2, considered the leading standard for the design of safe closed-circuit ammonia refrigeration systems.

Some of the changes to the 2021 edition of IIAR-2 include:

  • Requirements for eyewash/safety showers have been reorganized and clarified.
  • Ammonia-detection requirements have been changed.
  • Changes to machinery-room exhaust and ventilation have been updated based on new requirements.
  • New requirements for evaporators are included concerning design for freeze protection and design for frozen products.
  • Inclusion of emergency pressure-control systems, where required by authorities having jurisdiction (AHJs).

New appendices in IIAR-2 include:

  • O: Designing to Avoid Component Failure Caused by Abnormal Pressure or Shock.
  • P:  Removal of Water from a Refrigeration System.
  • Q: Guidelines for the Identification of Ammonia Refrigeration Piping and System Components.

Over the past five years, model code bodies – including the International Mechanical Code (IMC), ASHRAE-15, the Uniform Mechanical Code (UMC), and the National Fire Protection Association (NFPA) – have decided to defer to IIAR 2 and other IIAR standards as the basis for regulating ammonia.

This year, the International Fire Code (IFC) tentatively approved a proposal for the 2024 edition of its model code – still subject to public comments – to defer all matters related to ammonia refrigeration, including safety, to IIAR standards.

IIAR 2 “incorporates topics traditionally addressed in other codes and standards making it the single most comprehensive standard covering the safe design of closed-circuit ammonia refrigeration systems published to date,” said IIAR.

First issued by IIAR in March of 1974, IIAR 2 underwent a major update in 2015 when, for the first time, it addressed ammonia equipment outside of the machine room in industrial settings; this included a section on low-charge ammonia packaged systems.

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