Page 154 - Pipeline Rules of Thumb Handbook

Hydrostatic Testing 141

Volume required at test pressure

2
.
V tp = V ¥ F wp ¥ F pp ¥ F pwt (2) V = 0 0408 ¥ (10 75 -(2 ¥ 0 279 )) ¥ 5 280, ¥ 5
.
.
= 111 888 gallons
,
V tp = Gallons contained in test section at test pressure P, and
temperature T - °F.
Volume required to achieve test pressure = V tp = V ¥ F wp ¥
F pp ¥ F pwt .
F wp = Factor to correct for the compressibility of water
due to increasing pressure from 0psig to test pressure P,
psig F wp = 1 1 - ( [ 4 5 10 -5 ) ¥ (2430 14 73. )]
.
¥
.
= 1 007479.
F pp = Factor to correct for volume change in pipeline due to
pressure increase from 0psig to test pressure P, psig
1
F pp =+ ( [ 10 75 0 279 ) ¥ (0 91 2430. ¥ (30 ¥ 10 6 ))]
.
.
- )]
F pwt = Factor to correct for the change in water volume and +[3 6 10 -6 ¥ (50 60
¥
.
pipe volume due to change in pipe and water temperature = 1 002804.
from base of 60°F to pipe and water test temperature, T -
°F.
F pwt = F pt F wt
.
¥
.
1
F wp = [1 -(4 5 10 -5 ) ¥ P ( 14 73 )] (3)
6
1
F pt =+ ( [ 50 - ) ¥ 18 2 10 -6 ]
¥
.
0
P = Test pressure, psig.
.
= 0 999818
F pp =+ ( [ D t) ¥ (0 91 30 10 6 )]
.
¥
P
1
F wt = 0 9993061 ( from Table ) 1
.
60
¥
+[3 6 10 -6 ( T - )] (4)
.
.
.
D = Outside diameter of pipe, inches. F pwt = 0 999818 0 9993061
t = Pipe wall thickness, inches. = 1 000512
.
T = Pipe temperature, °F.
.
,
¥
V tp = 111 888 1 007457 1 002804 1 000512
¥
¥
.
.
F pwt = F pt F wt (5)
,
= 113 099 gals.
F pt = Factor to correct for change in pipe volume due
to thermal expansion of the pipe from base temperature of Incremental volume required to reach test pressure, P.
60°F.
F pt =+ ( [ T - ) ¥ 18 2 10 -6 ] (6) = 113,099 - 111,888 = 1,211gals.
0
6
1
.
¥
F wt = Factor to correct for thermal change in specific After a period of time, the test pressure, P has decreased
water volume from 60°F to test water temperature. Refer to to 2,418psig and the temperature of the pipe and test
Table 1. water has decreased to 48°F. The calculation procedure
previously described may be repeated to determine if
Sample calculation: the pressure decrease is attributable to the decrease in
temperature.
Pipe Size: 10.750≤OD ¥ 0.279≤w.t. X-52
Length: 5 miles V = 111,888gals.
Test pressure: 2,430psig
P 1 = 2,422psig
Temperature: 50°F
T 1 = 48°F.
F wp1 = 1.007454
Use equation 1 to determine the initial line fill volume, V. F pp1 = 1.002796