Ammonia Update

Recent incidents involving ammonia at ice rinks have occurred prompting the release of this alert.

In one incident, ammonia was released from the refrigeration system at an ice rink when maintenance personnel were draining oil from the system. This incident resulted in injuries to workers when they attempted to close a valve and were exposed to high levels of ammonia while not wearing appropriate protective gear. In another incident, maintenance personnel had just finished adding oil to a compressor when ammonia was released from the refrigeration system through a valve which had not been fully closed.

Preventative Measures

In order to prevent similar incidents as those described above, employers using ammonia in their mechanical refrigeration systems must:

  1. Comply with the Occupational Health and Safety Act and Regulations; the Public Safety Act and the Boiler, Pressure Vessel and Compressed Gas Regulations and the CSA B52 Mechanical Refrigeration Code
  2. Examine mechanical ventilation systems Airborne concentrations of ammonia must be within the limits of those determined by the American Conference of Governmental Industrial Hygienists. Mechanical ventilation systems can prevent harmful gases from accumulating.
  3. Consider the use of additional detectors The installation of detectors and audible alarms are required by CSA B-52 inside mechanical rooms. The installation of detectors with alarms in areas outside mechanical rooms can provide notification if ammonia levels exceed acceptable limits in those areas.
  4. Develop written safe work practices and procedures The attached “Guidelines for Draining Oil from and Adding Oil to Ammonia Refrigeration Systems” are provided for guidance.
  5. Develop an emergency response plan The emergency response plan should include training for workers and ensure that emergency response equipment is available in the event of an ammonia leak.

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