The Negative Side of Sprinkler Systems

While certainly beneficial in case of fire, sprinkler systems can cause great damage, so, the risk of having a sprinkler system should also be recognized.

One day, after a very cold night in January 2009, here in Northern Virginia, I, an electrical contractor, was called to check out electrical outlets that had been soaked with water. The culprit in this nearly-new town-house in Arlington was the sprinkler system supply pipe which had burst from freezing. The pipe was located above the ceiling in the garage.

I saw the disastrous effects of a sprinkler system gone awry--the aftermath--the flooding and related damage from the gushing of the high-pressure / high volume water-flow of the sprinkler system's plumbing. Sprinkler systems have more than twice the amount of water-pressure and -volume than has ordinary domestic pluming. After the pipe-damaging ice melts, the water, under pressure, is free to run out of the damaged area.

 Although it is desirable to also have sprinkler fire protection in the garage, the main fault of this system was the sprinkler's location. Even though the pipe was protected by its installation above the thermal insulation (adjacent to the heated, living-space), there wasn't enough heat in the unheated garage or in the bedroom above to keep the water in the pipe from freezing. In this case, the residents had the garage door closed. But, what R-value was the door? Was the thermostat in the living-space above turned down before the freeze? Details such as the presence of heat sufficient enough to keep any water pipes from freezing is paramount in the design of a dwelling. In this assemblage of modern town-houses a total of 8 had similar pipe freezes that night.

Making the matter worse, another fault was that the pipe was made of plastic: fire-rated CPVC. Unlike the smaller open-split, freeze-damage to copper pipe, this more brittle material violently cracks open from the expanding ice, leaving a much bigger breech in the pipe. So, the high-pressure and -volume water gushed out. Fortunately, the garage was situated slightly below the interior-house level so, the flood-water didn't enter the living space. But, the water did run out onto the street leaving a thick sheet of hazardous ice. Another case of sprinkler supply-pipe freeze damage:

That same night prompted a disaster at a friend's twenty-five-year-old town-house in Falls Church. In her case, the sprinkler supply pipes, burst while she was away at work.

She and her boyfriend came home to the mess. The neighbors told them that they had phoned the fire department, and that they arrived earlier, broke open the front door to shut off the gushing water. But, upon entering, my friends heard the sound of running water--the flood continuing! He runs to the basement finding that the firemen shut off the wrong valve--the domestic water valve, not the sprinkler system valve!

The house was a catastrophe; many of the soaked gypsum walls had fallen, further damaging furniture and antique porcelain curios.

The fault here was that the supply plumbing for the top-floor sprinklers was incorrectly installed. The pipes were placed above the insulation leaving them vulnerable to the coldness of the unheated attic. Fortunately, the plumbing was made of copper; in my estimation, were it made of the CPVC, there would have been more flood damage.

Because of similar past troubles my friend's neighbors keep their sprinkler main-valves off (they neglected to tell her of their solution). After her several-month stressful restoration of her home and life, all is well. No more will she fall victim to a failed sprinkler system: although the sprinkler system was repaired, she says: "The sprinkler system valve shall remain in the closed position!"

Unfortunately, since the past several decades, many municipalities often permit shoddy construction!

Richard Stuart Otto, 5 October 2009