Potter Releasing Systems - Manual (Page 42)

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Semi-annually Check cold weather valves (if provided) in the Fall, before freezing weather.
The valves should be closed and that portion of the system drained. In the
Spring, as soon as freezing weather has passed, the cold weather valve should
be reopened.
Note: Cold weather valves are sometimes used to isolate a portion of a
sprinkler system that might be subject to freezing temperatures. During
cold weather, the valve is closed and that portion of the system is drained.
However, cold weather valves are not desirable, as protection is not provided
during cold weather or if valve is inadvertently left closed. Also, NFPA 13
does not recognize cold weather valves. A preferred arrangement would be
to provide a dry pipe system in the unheated area, or an antifreeze loop in a
small area.
Pipe Blockage
It is important that the sprinkler system piping be maintained free of obstructions,
so, periodically, sprinkler systems — including valves and piping — should be
examined internally. Where unfavorable conditions such as those listed below are
found, the systems should be examined for blockage immediately, and at five-year
intervals thereafter. Look for:
A. Defective screens at pump intakes where pumps take suction from
streams, ponds or lakes. Failure of the screens might allow debris into the
pump suction and into the system piping.
B. Debris and obstructive material discharged during routine water tests, such
as from hydrant water flow tests or 2-inch main drain tests.
C. Debris found in dry-pipe valves, check valves and fire pumps during
maintenance.
D. Heavy discoloration of water during 2-inch drain tests, or plugging of the
inspector’s test connections.
E. Plugged piping, which is found during system alterations or after system
failure during fires.
F. Failure to flush underground mains following installation or repairs.
Debris might have been left in the piping during construction.
G. A record of broken water mains in the area. Repair of these broken pipes
could have introduced debris into the system.
Tests Tests are required at various frequencies as noted below. Use the Inspection Forms at the end of this
chapter to record all test results.
Quarterly All Sprinkler Systems:
Flow test main drains.
This involves noting and recording the pressure of the gauge on the
lower side of the sprinkler valve (Figure 2-2 above). (This is the static water
supply pressure.) Open the 2-inch main drain fully; after the
flow has stabilized, note and record the pressure on the gauge again.
(This is the residual water supply pressure.) If the pressure readings vary
significantly from those readings previously recorded, there is indication
that something may be wrong with the water supply — such as a closed
valve or blocked pipe. Loss of pressure of more than 10 percent should