4.17 Pre-Action Sprinkler System Supplied by Wet Pipe Sprinkler Systems

Reference: 2022 NFPA 13 Section 16.11.3.4 and 2022 Edition of the Automatic Sprinkler Systems Handbook.

When a wet pipe sprinkler system is the water supply source for a pre-action system, the wet pipe sprinkler system shall be provided with a non-paddle-type (alarm check valve) water-flow alarm indicator. If this is not possible, the pre-action system must be supplied with water from a connection to a riser or a wet or combination standpipe, upstream of the paddle-type water-flow alarms indicator.

For buildings having floors used for human occupancy located more than 75 feet above the lowest level of fire department vehicle access (high rise buildings), the pre-action system shall be supplied, in the manner described above, with water from at least two risers or standpipes.