The Fernie Memorial Arena incorporated one refrigeration system that provided cooling for two coolant systems; one cooling the arena floor, and the other cooling the curling rink floor. The refrigerant used was ammonia and the coolant in both systems was a calcium chloride brine solution. Heat was exchanged between the brine systems and liquid ammonia within two-pass shell-and-tube heat exchangers, referred to as chillers.
At 3:53 a.m. on October 17, 2017, an ammonia alarm in the arena’s mechanical room was triggered and the system was shut down. Between 9:15 a.m. and 9:38 a.m., rising pressure contained within the curling brine system led to the separation of a pipe coupling in the mechanical room. Upon separation of the coupling, an estimated 9 lb. of ammonia was rapidly released into the room followed by additional ammonia from the system. The atmosphere in the mechanical room may have reached or exceeded concentrations of 20,000 parts per million (ppm) of ammonia. Ammonia odour was reported from nearby areas of the community between 9:40 a.m. and 1:20 p.m.. At 12:50 p.m., an electrician discovered a worker in the mechanical room, called 911, removed the person, and performed CPR until the arrival of the fire department. A total of three people were found deceased in the mechanical room: the director of leisure services, the refrigeration operator, and a refrigeration mechanic.
The animation of the accident is below.
[youtube]https://www.youtube.com/watch?v=BBxzXKRSjsc[/youtube]
