NYC Pre-Action System

ron

Senior Member
Ok, what's a Pre-Action system?

-Hal
A type of sprinkler system that has supervisory air in the pipe and only allows water to flow into the pipe when the proper conditions activate, either detection (single interlock) OR detection & air exits the pipe (double interlock).

NYC only allows single interlock.
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
A type of sprinkler system that has supervisory air in the pipe and only allows water to flow into the pipe when the proper conditions activate, either detection (single interlock) OR detection & air exits the pipe (double interlock).

NYC only allows single interlock.
Commonly called a dry system. There is an air compressor that keeps the piping charged with air.

-Hal
 

ron

Senior Member
Commonly called a dry system. There is an air compressor that keeps the piping charged with air.

-Hal
Probably not worth arm wrestling about, but NFPA 13 defines them differently. Although pre-action systems normally have dry pipes in the protected area, it is different than a dry pipe system. A Pre-action system requires detection to activate.

Technically there is such a thing as a non-interlock pre-action system that is essentially a dry pipe system, but nobody really goes through that listing process when a cheapo dry pipe system listing is easier and cheaper to get.
 
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