Ammonia leak shuts down traffic near arena

Mona Mattei
By Mona Mattei
October 23rd, 2010

Emergency protocols kicked into play last night as a chemical leak at the Grand Forks Arena shut down a two-block radius of traffic. John Mackey, director of recreation and facilities, explained that a mechanical failure in the refrigeration plant caused the pressure relief valve to go off releasing 5o pounds of ammonia into the air.

  “Instead of a switch going off to close it down, the switch failed and resulted in pressure build up,” said Mackey. “The pressure relief valve, which is designed to do that, then released somewhere around 50 pounds of ammonia.”  The unit that failed was on the cooling tower on the exterior of the arena. Darryl Funk, the operator on duty, just happened to be outside when the valve went off. After shutting off the system, Funk evacuated the building.  “Staff called 911, evacuated the building, the fire department showed up and cleared the building,” said Mackey. “He (Darryl) heard it go off and he went around to the front of the building and you could see a cloud of gas on the ground. It’s very heavy so it drops right to the ground.”  Mackey said that the fire department brought in fans to clear the air and exhausted it all.  “It wasn’t till after midnight that we knew exactly what happened,” Mackey commented. “A broken line would have been disastrous because the broken line would have been in the condenser and there’s probably about 300 feet of line in there. As it turned out is was the pressure relief valve that went off.”  The refrigeration technician from Kelowna diagnosed the problem when he started troubleshooting the system. The plant was up and operating by about 2:00 a.m. and a failed motor was replaced later on Friday, Oct. 22.

Categories: General