Description
SPRINKLER ALARM MODEL – GA
HD Sprinkler Alarm is a hydraulically driven mechanical
bell. It does sound a continuous alarm when the
sprinkler system operates. The impeller and drive
shaft are energy efficient, made from light weight
nonmetallic material and do not require any external
lubrication. The gong, protection cover and motor
housing are made of corrosion resistant aluminium
alloy.
Sprinkler Alarm with mounting Type-B is wall mounting
type. Type-B is suitable for 50 to 250 mm thick wall
and curves with 325 mm long drive shaft as standard
supply. For wall thickness 250 to 450 mm or longer
a special extension drive shaft can be supplied on
request.
OPERATION
When the sprinkler system is activated by fusing of
one or more automatic sprinklers at fire condition,
the water flows through the Alarm Valve/Deluge Valve
and enters the sprinkler alarm through the nozzle,
creating a high velocity jet which strikes the impeller
causing the drive shaft and the striker arm assembly
to rotate. The alarm arm assembly rotates and strikes
to impact against the aluminium gong, producing a
continuous alarm. The waste water then drains out
through a 25NB drain outlet.
DESIGN REQUIREMENT
Strainer is required in the Sprinkler Alarm line to
protect the 3.2 mm nozzle in the water motor housing
from clogging.
The alarm line pipe must be 20NB (3/4”) size with
22.8 mtrs. (75 feet) maximum total length of pipe
with minimum number of fittings. If the length of the
pipe exceeds 22.8 mtrs. (75 feet), then higher size
pipe must be used to reduce hydraulic friction loss.
The Sprinkler Alarm should not be located more than
1.8 mtrs. (Six feet) above Alarm Valve / Deluge Valve.
One Sprinkler Alarm may be connected to one
or maximum of three alarm lines of separate
fire systems. For interconnecting more than one
Sprinkler Alarm, a swing check valve in each line need
to be provided.
MAINTENANCE
Qualified and trained person must commission
the system. After few initial successful tests an
authorised person must be trained to perform
inspection and testing of the system.
Even though corrosion resistant material is used
in the construction of the Sprinkler Alarm, it is
suggested that the Sprinkler Alarm be examined and
tested at regular intervals to ensure that the nozzle
is free from obstruction and the impeller is free to
rotate. The inspection should include the following, in
addition to any specific requirement of NFPA, or as
required by authority having jurisdiction.
1. Clean the 20 NB (3/4”) Strainer provided in the
alarm line.
2. Open the 3/8” plug provided on the inlet of the
Sprinkler Alarm and clean out any accumulated
particles.
3. Detach the Gong, clean the internal surface and
refit in proper sequence.
4. Activate the Sprinkler Alarm to verify clear and
steady sound
