American National Standards Institute's Board of Standards Review approved IIAR 2-1999, American National Standard for Equipment, Design and Installation of Am-monia Mechanical Refrigeration Systems, as revised by International Institute of Ammonia Refrigeration (IIAR). The standard is a guide to the design, manufacture, installation and use of ammonia mechanical refrigerating systems in industrial occupancies.

All requirements specified by the revised standard are written in mandatory code language. Changes include:

  • Flammability limits.
  • Positive-displacement compressor relief protection.
  • Isolation procedures for pressure-relief piping.
  • Relief requirement exceptions.
  • Hydrostatic relief requirements.
  • Pressure testing requirements.
  • Safety and testing for valves and controls.

Organization of the standard was simplified into four sections: general information, equipment, machinery room design and installation. Four appendices also have been added, and equipment and components not covered in the previous standard are addressed.

The new standard is available by calling (703) 312-4200 or via IIAR's online publications store at