A cold storage facility in the food service industry was originally built in 1992 with one (1) preaction system covering the freezer area that is kept at (-10ºF). Wayne Automatic Sprinkler Corporation located in St. Louis, MO has been contracted for the facility fire sprinkler inspection and service. As part of the quarterly maintenance procedures, Wayne Automatic Sprinkler routinely inspects the supervisory gas supply line and preaction system mains for ice plugs.
The preaction system was maintained with a legacy Dry Air Pac™*. Ice was continually found in the air supply line during the quarterly inspections. Not only was ice present in the air line at the freezer penetration, it also occasionally caused a total blockage in the preaction air supply line.
These ice plugs resulted in frequent supervisory low air signals. Additionally, the fire alarm control panel was programmed to receive the supervisory low air signals as alarm signals which resulted in the facility’s horns and strobes being activated and the fire department being dispatched.