From the National Fire Sprinkler Association:
The designers and installers of water-based fire protection systems, like automatic fire sprinkler systems, take into account seasonal variations in temperature. In cases where water-filled pipe cannot be protected from freezing, alternative methods are used. But most of the time, even in the coldest climates, the assumption is that the normal precautions taken to keep the building warm will, in turn, keep the fire sprinkler system from freezing.
NFPA 25, the Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems, published by the National Fire Protection Association, is required by code to be followed in most areas of the country. Because of the importance of adequate heat, the standard requires that the owner of the property maintain at least a 40 degree temperature in all areas containing water-filled piping.
Although rare, freeze-ups can and do still occur. Allowing water-filled components of a fire suppression system to freeze can lead to a catastrophic event like a rupture or even worse, the failure of the system to operate in a fire. The time to prevent this from happening is before cold weather strikes. But even during cold weather, there are still important steps that anyone in buildings with fire sprinklers can take to avoid these costly and potentially tragic freeze-up from occurring:
- Obviously, most important is to make sure heating systems are in good working order and the thermostat is set high enough to prevent freezing temperatures in all areas of the building.
- In buildings with drop-ceilings, sometime removing a few tiles in each room will allow heat to travel into otherwise cold areas.
- If cold drafts are noticed, locate the source and take steps to remedy them. Sometimes doors or windows don’t close tightly because of snow or ice, or cracks open up around other openings and need caulking. Doors leading to poorly heated vestibules may need to be left open at night to allow heat into that area.Remember, freeze-ups are not failures of the fire sprinkler system, but the results are just the same. A lack of adequate heat provided to the water-filled components of the fire sprinkler system can be avoided by taking these simple precautions. The qualified sprinkler contractor who does the routine inspection, testing and maintenance on your system can provide you with additional guidance. You can usually find their contact information somewhere on the system riser (where the main control valves are located).