The latest version of IIAR 2, a standard for the design of safe closed-circuit ammonia refrigeration systems, has been published by the International Institute of Ammonia Refrigeration (IIAR).

Some of the changes to ANSI/IIAR 2-2021 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.

IIAR Standards contain both normative and informative information, establishing both the minimum requirements for industry compliance and advisory information where applicable.  IIAR Standards are ANSI approved as they are subject to a rigorous public review and reaffirmation process every 5 years to ensure that they represent an industry consensus.

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. 

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