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Dry Pipe

Dry pipe systems also have closed sprinkler heads: the difference is the pipes are filled with compressed air. The water is held back by a valve that remains closed as long as sufficient air pressure remains in the pipes. As the dry pipe sprinkler heads open, the air pressure drops in each pipe, allowing the valve to open and send water to that head.

Dry pipes are often used in areas where water may freeze, such as parking garages.

Deluge

Deluge systems are similar to dry pipes, except the sprinkler heads are open and larger than dry pipe heads. The pipes are empty at normal air pressure; a deluge valve holds the water back. The valve is opened when a fire alarm (that may monitor smoke or flame sensors) triggers.

Pre-Action

Pre-action systems are a combination of wet, dry, or deluge systems, and require two separate triggers to release water. Single interlock systems release water into the pipes when a fire alarm triggers. The water releases once the head opens. Double interlock systems use compressed air (same as dry pipes): the water will not fill the pipes until both the fire alarm triggers and the sprinkler head opens.

Pre-action systems are used in areas such as museums, where accidental discharge would be expensive. Double-interlock systems are used in cold areas such as freezers to avoid frozen pipes.

Portable Fire Extinguishers

All portable fire extinguishers should be marked with the type of fire they are designed to extinguish.

Portable extinguishers should be small enough to be operated by any personnel who may need to use one. This means those old brass monster extinguishers are not a recommended control.

Use the “PASS” method to extinguish a fire with a portable fire extinguisher:

  • Pull the pin
  • Aim low
  • Squeeze the pin
  • Sweep the fire