Ch. 6 Sprinkler/Standpipe Ops Flashcards
3 factors that remove fresh air (fire in sprinkler bldgs):
Increased CO.
Sinking fire gases.
Smoke being pushed down.
In fighting fires in a sprinklered building, ______ is an absolute must but will often be ______.
Ventilation.
Extremely difficult
PPV=extremely valuable, HVAC May be only way
Most common and simplest type of sprinkler is _______.
Automatic wet system
Automatic wet sprinkler has an alarm valve which: (2)
1) is primarily a check valve (prevents water flowing back out of system).
2) when valve opens, transmits alarm (small piping)
Which sprinkler system will reset itself? Automatic wet or automatic dry?
Automatic wet
When supplying sprinkler: (3)
Short lines.
Volume mode.
150 psi
If false alarms recur at same location (2)
Notify building owner that repeats won’t be tolerated.
-contractors can adjust piping so water can flow for longer period. Delay can be UP TO 1 MINUTE.
Also try to find the cause of the problem.
After automatic wet system, this the next most common sprinkler system type:
Automatic dry (dry-pipe)
Dry-pipe sprinklers are more complex or less complex than automatic wet?
More complex, fire dept’s have more difficulties with dry-pipe
Sprinkler
Dry-pipe valve functions similarly to wet-alarm except for:
Clapper valve has much larger top than bottom surface.
Clapper equipped with lock-OPEN feature (water columning)
Dry-pipe sprinkler air and water pressures
Air (top) 30-40 psi.
Water (bottom) up to 100 psi.
“Differential dry-pipe valve”
Water columning prevalent in what sprinkler system:
Dry-pipe
FF’s respond to dry-pipe sprinkler trip and silence the alarm, 2 problems they face:
1) Another alarm won’t be received for actual fire.
2) if system freezes, no water flow and ice in pipes blows system apart
This type of sprinkler system is connected to water source controlled by an automatic valve.
Deluge
heads merely nozzles
This type of sprinkler system is consists of automatic detection system coupled with an automatic dry-pipe system.
Preaction
action for detection
Preaction system uses ______ sprinklers while deluge uses _____ sprinklers.
Closed. Open.
In Preaction system, _______ heads must activate to prevent _______.
2 or more.
False alarms
Sprinkler head pressure and flow rates
100 psi = 55-60 gpm.
50 psi = 40 gpm.
5 psi = 10 gpm.
3 exterior signs of sprinkler:
Presence of siamese.
Sight or sound of water alarm gong.
Running water discharging from pipes coming through wall of bldg
The best way to determine whether or not a sprinkler system is present is:
By prefire inspection and planning.
Also familiarizes with control valves, type and operational status
Upon our arrival at sprinklered bldg, what determines our course of action:
Whether or not sprinkler system is operating
3 reasons not to wait for owner with keys
Aren’t positive there isn’t cause for an alarm.
(Defective gongs, valves shut off, debris in the lines).
Failure to act may let fire intensify.
Some very valuable equipment may be exposed to damage
When departments decide to use _____, _____, or ______ hose and _____ nozzles, they violate the hydraulic design of the standpipe systems.
1 1/2”, 1 3/4”, 2”. Fog
Some type of device will restrict the pressure to ____________ on 1 1/2 in. OUTLETS
A maximum of 80 psi (100 psi after 1993)
Class II (hose cabinet) standpipe max
100 gpm (flow)
Relief valves or other pressure-control devices required to ensure maximum pressure at TOP-FLOOR outlets is ____________ where 1 1/2” OCCUPANT HOSE is provided
No more than 65 psi (100 psi after 1993)
(Standpipes) Whenever there is a serious fire, a good practice is :
Supply 1st floor hose outlets for each riser, IN ADDITION TO Siamese
Class I standpipe
Primarily for use by:
Fire dept. personnel OR.
Others trained in handling heavy fire streams
Class II standpipe (just hose cabinet) {GPM!!}
For use by bldg occupants to control MINOR fire, with 1 1/2” hose, with open tip or fog nozzle - only 100 GPM!!!!
Class III standpipe
Allow fire dept to use heavy hose streams, as well as provide FIRST-AID HOSE for occupant use prior to arrival of dept.
Can be 2 1/2” outlet AND 1 1/2” outlet
OR
2 1/2” outlet WITH 1 1/2” reducer
Class III standpipe on 1 1/2” outlet: more than 100 psi can be dangerous to untrained user
Some type of device to RESTRICT pressure on 1 1/2” hose OUTLET to 80 psi (100 psi after 1993)
Class III standpipe for 2 1/2” outlet
After 1993, permits up to 175 psi (minimum 100 psi)