Detection & Release Flashcards
2 kinds of valves for pre action and deluge are
Latch Clapper Valves
Differential Type Valves
Where is the chamber for a Latch Clapper valve
Isolated from the rest of the valve
Define how a latch clapper valve operates
When the isolated chamber receives water pressure, it acts on a lever to hold the valves clapper against supply
2 examples of latching pre action valves are
Reliable B & BX
Grinnell/Gem Multimatic Model A-4
What kind latching mechanism does a ASCOA model F pre action valve use
Diaphragm actuator
Differential Ratio for Pre-Action Valves is generally
2-3.2 to 1
The 3 most common actuation methods are
-Wet Pilot Lines
-Electrical Detectors
-Pressurized Air or Nitrogen Pilot lines
What is the most simple actuation method
Wet Pilot Line
If automatic sprinklers are used as detectors, how must they be installed
In accordance with their listing as sprinklers
When a sprinkler head has a different deflector and is designed to be used in a pilot line what are they called
Fixed Temperature Release Device
Some Fixed temperature release heads for pilot lines can go how far apart
40ft x 40ft
What limitations do wet Pilot lines have
-How high they can be above the valve
-Total length of pilot line piping that can be run without increasing size
(Manufacturer specifies exact amount)
When sprinklers are subject to freezing, what must pilot line contain
Pressurized air or nitrogen
The transition from water to air, in a pneumatic pilot line is made with
Dry-Pilot Actuator, installed on pilot line near valve
The pneumatic actuator is what kind of “valve”
Deferential valve
Model C rate of rise release will activate when
Temperature increase of 15F per minute
Model C Rate of rise release is also equipped with what, for smoldering fires
A fixed temperature detector as a safeguard
How many C1 Releases can be placed on a single line
No limit
How is the C1 Releases reset
Self Resetting
How does the C1 Release operate
The tube element expands faster the the rod element, causing a pulling force on the lever arm, then depresses Schrader valve, venting pressure
C1 release preset standard gap is
0.025”
C2 release pre set gap is
0.018” gap
What keeps a preaction/deluge valve open?
Pressure Operated Relief Valve (PORV)
The PORV will remain open until the pressure from the sprinkler system drops below
5psi