As temperatures drop, the potential for sprinkler freeze failures rises. Dry pipe sprinkler systems are one way to avoid of freeze failures, but even they are not immune.

Wet Pipe Sprinklers vs. Dry Pipe Sprinklers

As we mentioned in our “Fire Sprinkler Freeze Failures” post back in February, when you need sprinklers in environments that regularly drop below 40˚F, wet pipe sprinklers won’t meet the challenge. In wet pipe systems, the pipes are filled with water, which could freeze in low temperatures. Frozen water can mean burst pipes, broken fittings, and potential leaks as the ice melts.

Dry sprinkler pipes, on the other hand, are filled with compressed air instead of water. In the event of a fire or other sprinkler trigger, the compressed air is released, a valve opens, and the pipes fill with water.

In her recent BUILDINGS magazine article, “A Guide to Dry Pipe Sprinklers,” Jennie Morton writes, “Dry pipe sprinklers are used in applications where you can’t protect pipes from freezing temperatures. These areas include:

  • Exposed garages
  • Drive-through loading areas or docks
  • Water-sensitive storage
  • Unheated warehouses
  • Garden or supply centers
  • Cooler or freezer storage
  • Unconditioned attics”

Slope and Condensation

Dry sprinkler system pipes should be sloped back to the water source or an auxiliary drain so that after the system’s been used, excess water can exit the pipes. However, if pipes are not adequately sloped or improperly installed in terms of drainage, water left in the pipes can freeze. This can cause problems similar to those which occur in wet pipe freeze failures.

Water can also collect in dry pipes, Morton notes in her article, due to condensation resulting from compressing the air in the pipes. Frozen condensation can plug a sprinkler’s valves, preventing water from entering the pipes in the event of a fire.

Dry Pipe System Maintenance

In our post “How to Prevent Fire Sprinkler Freeze Failures,” we recommend a few routine maintenance procedures to help prevent freeze failure in dry systems. We also suggest that licensed and properly experienced fire protection contractors perform all work on fire sprinkler systems. If you would like to know more about dry pipe freeze failure or you’d like your system checked before winter hits, we’re here to help.

By Jeff Harrington, CEO and Founder of Harrington Group, Inc.