A wet fire protection system is a network of piping attached to
a public or private water supply, containing a control valve, pressure
gauge, alarm mechanism, drain, fire department connection, and alarm
testing apparatus. The network of piping contains sprinkler heads
spaced to accommodate the hazard per NFPA standards. Sizing of this
piping can be pipe schedule, meaning so many sprinkler on a particular
pipe size or hydraulically designed system where the limit of sprinklers
is controlled by the available water supply volume and pressure.
The way to establish pipe schedule system or calculated system is,
a calculated system should have a hydraulic placard on riser. Also
see Standpipe System for additional
Main Points to Establish
* Is the main control valve open and all valves down stream of the
connection to the water supply open?
* Is this and all other valves controlling water to the system locked
in the open position or supervised and functioning?
* The pressure gauge should indicate that the system is filled with
* There are two types of mechanisms, water flow switch and water
* Are there wires connecting the water flow switch to bells or supervisory
panel? Do alarms work when inspectors test is opened?
* A water motor gong will have a by-pass valve to allow the ringing
of the bell.
* This valve allows the system to be drained and is used to test
to see if the city water valve is open. This is done by opening
the valve wide open while reviewing the pressure drop on the pressure
gauge. The loss should not be significant. If it is the city water
supply should be investigated.
Fire Department Connection
* This is used to allow the fire department to pump into, using
their pumper truck to supplement the city water pressure. Threads
should be checked to see if they meet standard threads used by local
Alarm Testing Apparatus
* This is usually a 1" located somewhere in the building and
piped to the outside or a drain capable of sustaining a full 1"
flow equivalent of one sprinkler orifice. When this valve is opened
the alarm must ring.
* There should be a supply of extra sprinklers in the facility as
per NFPA #13 and a sprinkler wrench.
* As you walk through a facility there should be no gaps in coverage
in those areas requiring sprinklers.
* The question should be asked if any area has been changed from
one occupancy to another after original system had been installed.
* Are any sprinklers blocked or painted?
* What is the age of the sprinklers?
Certification of Inspection
* The owner, under NFPA #13A, is responsible for certain tests and
the collection of certain data to demonstrate the performance capability
of the system. The owner should have documentation of periodic testing