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Preventing weather-related water damage due to automatic sprinkler systems: factors to consider that help keep property unharmed.

Article Excerpt
Sprinkler systems may be our best choice in the struggle between fire, life safety, and property protection, but water damage happening on, or shortly after, a cold winter day, can be very expensive for property owners and occupants--and need not involve a fire. There are a number of factors that can contribute to a weather-related large water damage loss: The building enclosure, some of the building's mechanical systems, the homeowner or occupant, the sprinkler system design and installation, and the choices made by the design team (architect, fire protection engineer, mechanical engineer, design/build general contractor and so on).

Any one of these variables, alone or in combination, may lead to a large water damage loss--See Figure 1. In addition to the areas that will be identified, it is recognized that failures can occur from manufacturing or fabrication problems and installation mistakes.

Weather

The weather can become a factor any time temperatures are below 40[degrees]F and water is present, because the possibility of freezing exists. The length of exposure to temperatures below 40[degrees]F, the chemical content or makeup of the water, whether the water is moving or not, and so on definitely affect the potential for freezing.

As the air temperature goes down, and the wind speed picks up, the potential increases significantly. Low temperatures below -20[degrees]F are not uncommon between November and February in many parts of the northern United States and Canada. Actual air temperature extremes, not to be confused with wind-chill temperatures, can go below -40[degrees]F.

Table 1 shows temperature and wind speed data for a winter day in a Minneapolis, MN, suburb where at least one sprinkler system break occurred. If the design of the building and sprinkler system has not been based upon these minimum temperatures, and if the designers...