A wet pipe sprinkler system is a sprinkler system employing automatic sprinkler heads attached to a piping system containing water and connected to a water supply so that water discharges immediately from sprinklers opened by heat from a fire.
Each sprinkler is activated individually when it is heated to its design temperature. Most sprinklers discharge approximately 20-25 gallons per minute (gpm), depending on the system design. Sprinklers for special applications are designed to discharge up to 100 gpm.
Dry Pipe Fire Sprinkler
Systems
A dry pipe sprinkler system is a system with automatic sprinkler heads attached to a piping system containing air or nitrogen under pressure. The release of this pressure (as from the opening of a sprinkler) permits the water pressure to open a valve known as a dry pipe valve and the water then flows into the piping system and out of the open sprinkler head. Dry pipe sprinkler systems are installed in areas where wet pipe systems may be inappropriate such as areas where freezing temperatures might be expected. |
Deluge Fire Sprinkler Systems
The arrangement of
deluge fire sprinkler system piping is similar to a wet or dry pipe system with two
major differences: |
A pre-action sprinkler system is similar to a deluge sprinkler
system except the sprinklers are closed. This type system is
typically used in areas containing high value equipment or contents
and spaces which are highly sensitive to the effects of accidental
sprinkler water discharge. The pre-action valve is normally closed
and is operated by a separate detection system.
Activation of a fire
detector will open the pre-action valve, allowing water to enter the
system piping. Water will not flow from the sprinklers until heat
activates the operating element in individual sprinklers. Opening of
the pre-action valve effectively converts the system to a wet pipe
sprinkler system.
In a pre-action system the piping is pressurized with air or
nitrogen, monitoring of this air pressure provides a means of
supervising the system piping. Loss of the supervisory air pressure
in the system piping results in a trouble signal at the alarm panel