Winter Water Woes for Dry Sprinkler Systems

With winter in the northeast, we think of the dry air indoors and the crispness a wind and cold temperatures outdoors. We tend to think more about our water filled plumbing lines at home than compressed air or dry systems at work. But remember:

Dry systems can freeze. Water is ever present in air.
~ Greg Brewer, Service Manager

When we are inspecting sprinkler systems there are a wide range of components we check, including what part of the system is exposed to the elements. We remind business owners that having a dry sprinkler system does NOT mean that pipes don’t freeze even though they are filled with air versus water. Air has water in it – even when filtered.

I found this interesting example of water condensation from Plant-Maintenance.com.

For a 200 HP compressor operating at 60 degrees with 40% relative humidity, 50 gallons of condensate was produced daily. When increasing the temperature to 90 degrees and 70% humidity the condensate produced increased to 260 gallons daily.

To be fair, dry sprinkler systems do not function within that range – the example was to drive home the point that temperature and humidity impact how much the moisture in the air translates to water condensing in the lines.

At PSI, what we have found during sprinkler inspections is any dip in the piping, clogged drains or improperly placed legs provides a place for water to condense and collect. Imagine air moving through a system from a heated office environment to an outside loading dock area. During the colder winter, water mist turns to water vapor, collecting on the inside of pipes and running to the nearest low point. Where water collects it freezes when the temperature drops. The freezing water expands, breaking fittings, pipe and seals and instigating a release of water from the sprinkler system. That’s never a call a building manager or business owner wants to get.

Keep in mind, even with a dry sprinkler system, you want to be aware of how water impacts performance.

• Test and monitor low temperature devices and air pressure. Remember, air pressure is what keeps the lines full and the valves closed against water.
• Test and maintain low point draIns. This is particularly important during seasonal changes or abrupt changes in temperatures.
• Be vigilant in maintenance of the air system including the source and piping system. Be sure that changes in physical layout or new installations do not interfere with piping slope or damage draIns.
• Plan and budget for quarterly and/or yearly inspections. For those of us that provide the service we bring the experience of seeing multiple systems monthly and can spot potential problems that are often difficult to see on a day-to-day basis.