Use the following diagrams for reference when reviewing the Hydraulic Hand Calculations Tying It
All Together Module:
Example 1 - Combining sprinkler flows on an end fed branch line:
Three heads are operating simultaneously on an end fed branch line. Ignore velocity pressure.
▪ Black Steel, Schedule 40 pipe, with standard fittings
▪ K = 5.6
▪ Density = 0.15 gpm/ft2
▪ Area of coverage = 130 ft2
▪ C = 120
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Example 2 - Combining sprinkler flows on a center fed branch line:
Three heads are operating simultaneously on one side of a five head branch line AND two heads
are operating simultaneously on the other. Ignore velocity pressure.
▪ Black Steel, Schedule 40 pipe, with standard fittings
▪ K = 8.0
▪ Density = 0.20 gpm/ft2
▪ Area of coverage = 130 ft2
▪ C = 120
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Hydraulic Calculations
Example 3 – Combining branch line flows through supply piping and a loop:
Branchline K-factor = 34.1
Flow = 147 gpm
Pressure = 26.67 psi
Coverage Area = Five sprinklers
Note the average flow per sprinkler at this pressure is: 147 gpm ÷ 5 = 29.4 gpm
Pipe: Black Steel Schedule 40 with Standard Fittings, C = 120
Our design area for this example will be fourteen sprinklers (five heads on the two most remote
lines and then only four heads on the next and last line in the area). That flow will then be
calculated through the overhead system to the base of the riser.
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