Water Spray Hydraulic Calculations

HYDRAULIC CALCULATION FOR WATER SPRAY SYSTEM PER NFPA 15 Without taking velocity pressure into consideration Nozzle I.D. and End Node Location 1

A

Flow in gpm 25.2

Pipe Size 1.05

Pipe Equivalent Fittings and Pipe Devices Length 1E 10.5 2 12.5 1T

2

A

25.2

A

B

26.08 25.2 51.28

1.61

B

B

51.28 51.28 102.56

1.61

E

D

0 0 103

1.61

D

D

0 54.3 157.3

1.61

C

F

0 105.1 262.4

1.61

F

G

0 437.9 700.3

4

Hose

0 250 950.3

Friction Loss psi/ft

Pressure Summary

0.20

0.5 5 5.5

0.20

1E 1T

7 12 19

0.09

1T

2 8 10

0.33

22 0 22

0.34

1 0 1

0.73

1T 1E

18 12 30

1.89

1E

5 10 15

0.14

0 0 0

-

1.05

0

0

20.54241 0.2165 2.482917 23.24183 20.54241 0.2165 1.092484 21.8514 23.24183 0 1.752139 24.99397 24.99397 0 3.324455 28.31843 28.5 -6.495 7.371955 29.37695 29.37695 -0.433 0.733431 29.67739 29.67739 -1.732 56.70423 84.64962 84.64962 5.196 2.072468 91.91808 91.91808 0 0 91.91808

Normal Pressure

Notes

P = (25.2/5.56)^2 = 20.5 psi

Equivalent K=25.2/(21.7)^(1/2) = 5.41

q = 5.41*(23.24)^(1/2) = 26.08 GPM

Adding Equal Amount of flow from other side of line which is symmetrical with nozzle 1 & 2

We have been given q = 103 GPM @ 28.5 psi and this node

q = 50.3* (29.37/25.4)^(1/2) = 54.3 GPM

q from B = 102.6*( 29.7/28.31)^(1/2) = 105.1

q = 381.6*(84.64/64.4)^(1/2) = 437.4

Adding 250 GPM as Hose Stream Allowances

BALANCING FLOW @ NODE A

• Only one pressure is inside the pipe – Use the higher pressure • Calculate an equivalent K-factor for the portion of the pipe with the lower pressure • Calculate the actual flow using the K-factor and the new pressure.

Balancing Flow : A

Calculate Equivalent K Factor = Q / (P)^(1/2) = 25.2/(21.7)^(1/2) = 5.41 Calculate Actual Flow = Keqv * (P-higher)^(1/2) = 5.41 * (23.2)^(1/2) = 26.1 GPM

BALANCING FLOW @ NODE D

• Only one pressure is inside the pipe – Use the higher pressure • Calculate an equivalent K-factor for the portion of the pipe with the lower pressure • Calculate the actual flow using the K-factor and the new pressure.

54.3 GPM @ 29.4 PSI

D

Balancing Flow :

103 GPM @ 29.4 PSI

Calculate Equivalent K Factor = Q / (P)^(1/2) = 50.5/(25.4)^(1/2) = 10.02 Calculate Actual Flow = Keqv * (P-higher)^(1/2) = 10.02* (29.4)^(1/2) = 54.3 GPM

BALANCING FLOW @ NODE C

• Only one pressure is inside the pipe – Use the higher pressure • Calculate an equivalent K-factor for the portion of the pipe with the lower pressure • Calculate the actual flow using the K-factor and the new pressure.

54.3 GPM @ 29.4 PSI

102.6 GPM @ 28.2 psi

C

Balancing Flow : 103 GPM @ 29.7 PSI

Calculate Equivalent K Factor = Q / (P)^(1/2) = 102.6/(28.2)^(1/2) = 19.32 Calculate Actual Flow = Keqv * (P-higher)^(1/2) = 19.32* (29.7)^(1/2) = 105.28 GPM

BALANCING FLOW @ NODE F

381.6 GPM @ 64.4 psi F

262.4 GPM @ 84.64 psi

437.46 GPM @ 84.64 psi

• Only one pressure is inside the pipe – Use the higher pressure • Calculate an equivalent K-factor for the portion of the pipe with the lower pressure • Calculate the actual flow using the K-factor and the new pressure. Balancing Flow :

C

Calculate Equivalent K Factor = Q / (P)^(1/2) = 381.6/(64.4)^(1/2) = 47.55 Calculate Actual Flow = Keqv * (P-higher)^(1/2) = 47.55* (84.64)^(1/2) = 437.46 GPM