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Fire Protection Hydraulic Calculation
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Fire Protection
Hydraulic Calculations(Wet and Dry Systems)BSSI 1001
John Willden, P.Eng.
Hydraulic Equations
where: Q = USGPM AOP = Area of Sprinkler operations
1500 – 3000 ft2 for light hazard
Density = USGPM/ft2 or water/square foot
Q AOP Density for first sprinkler flow
Hydraulic Equations
where: Q = USGPM K=sprinkler factor p=pressure in psig
Q K p
2Qp for first sprinkler pressureK
Hydraulic Equations
where: Pf = pressure drop per foot (psig/ft)
Q = USGPM pipe flow F = friction factor from table
PF = total pressure loss
1.85fP FQ LPP fF
Hydraulic Example
Ordinary Hazard group 1 we get 0.15 USGPM/ft2
If each sprinkler is covering 130 ft2 we have:
Q =Q = Q = Q =
P =P = P = P = P = Q =
10 ft 10 ft 10 ft 10 ft
1 in1 in1¼ in1½ in
P = Q =
16 ft
Hydraulic Example
Q = Area x Density = 130 ft2 x 0.15 USGPM = 19.5 USGPM
Q =Q = Q = Q =
P =P = P = P = P = Q =
10 ft 10 ft 10 ft 10 ft
1 in1 in1¼ in1½ in
P = Q =
16 ft
p = (Q/K)2
= (19.5/5.65)2
= 11.91 psig
Hydraulic Example
Q = 19.5Q = Q = Q =
P =P = P = P = P = Q =
10 ft 10 ft 10 ft 10 ft
1 in1 in1¼ in1½ in
P = Q =
16 ft
pf = FC120 x Q1.85
= 5.10 x 10-4 x 19.51.85
= 0.124 psig/ft
Hydraulic Example
Q = 19.5Q = Q = Q =
P =11.91P = P = P = P = Q =
10 ft 10 ft 10 ft 10 ft
1 in1 in1¼ in1½ in
P = Q =
16 ft
Pf = pf x L = 0.124 x 10 ft
= 1.24 psig
Hydraulic Example
Q1 = 19.5Q2 = Q3 =
Q4 =
P1 =11.91P2 =
P3 = P4 = P5 = Q5 =
10 ft 10 ft 10 ft 10 ft
1 in1 in1¼ in1½ in
P = Q =
16 ft
P2 = Pf + P1
= 1.24 + 11.91= 13.15 psig
Hydraulic Example
Q1 = 19.5Q2 = Q3 =
Q4 =
P1 =11.91P2 =
P3 = P4 = P5 = Q5 =
10 ft 10 ft 10 ft 10 ft
1 in1 in1¼ in1½ in
P = Q =
16 ft
Q2 = K P2 + Q1
= 5.65 13.15 + 19.5= 20.49 + 19.5= 39.99 USGPM
Hydraulic Example
Q1 = 19.5Q2 = Q3 =
Q4 =
P1 =11.91P2 =13.15
P3 = P4 = P5 = Q5 =
10 ft 10 ft 10 ft 10 ft
1 in1 in1¼ in1½ in
P = Q =
16 ft
Hydraulic Example
Q1 = 19.5Q2 =39.99 Q3 =
Q4 =
P1 =11.91P2 =13.15
P3 = P4 = P5 = Q5 =
10 ft 10 ft 10 ft 10 ft
1 in1 in1¼ in1½ in
P = Q =
16 ft Now you try the next sprinkler
wet systems are always full of water they sprinkle when a head opens
TO SPRINKLERS
CHECK VALVE
ALARM VALVE(SPRINKLER VALVE)
INDICATING VALVE
SIAMESE CONNECTION(FIRE DEPARTMENT
CONNECTION)
FROM SERVICE MAIN
Details of Wet System
© 1997, The Viking Corporation
dry systems are full of compressed air they bleed off the air and sprinkle when a head
opensTO SPRINKLERS
FIRE DEPARTMENT CHECK VALVE
ALARM VALVE(DRY SPRINKLER VALVE)
INDICATING VALVE
SIAMESE CONNECTION(FIRE DEPARTMENT
CONNECTION)
FROM SERVICE MAIN
CHECK VALVE
Dry Pipe System
© 1997, The Viking Corporation
TO SPRINKLERS
CHECK VALVES
ALARM VALVE(PREACTION SPRINKLER VALVE)
INDICATING VALVE
SIAMESE CONNECTION(FIRE DEPARTMENT
CONNECTION)
FROM SERVICE MAIN
CHECK VALVE
preaction systems are full of compressed air until a fire is detected
then they fill with water to get ready
TO SPRINKLERS
CHECK VALVE
ALARM VALVE(PREACTION SPRINKLER VALVE)
INDICATING VALVE
SIAMESE CONNECTION(FIRE DEPARTMENT
CONNECTION)
FROM SERVICE MAIN
CHECK VALVE
deluge systems are empty and the sprinkler heads are open
they all come on at once when a fire is detected
Sprinkler Heads three major types
of sprinkler heads upright pendant sidewall
dry type
http://www.vikingcorp.com/databook/sprinklers/
Sprinkler Arrangements Tree systems
Only one path to each sprinkler head
Grid systems At least two
paths to each sprinkler head
Loop systems There are two paths to
each sprinkler head but the system can also be used to circulate heating or cooling water
Sprinkler Arrangements – cont’d
pendant
upright
Typical Alarm Valve
Parts of Alarm Valve
Fire Protection Symbolspendent head – hangs downupright head – stands upsidewall head – sticks out sidewaysupright (elevation view)pendent (elevation view)siamese connection – fire departmentcheck valve
Fire Protection SymbolsALARM VALVE (wet)ALARM VALVE (dry)ALARM VALVE (preaction)ALARM VALVE (deluge)flushing connection (flanged)flushing connection (cap)open stem and yoke valve (OS & Y)
FC
FC
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