TDW PIG-SIG V - Page 48

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Section IV – Pipeline Under Pressure
3.0 Continued
3.2 Checking Operation of Tapping Valve
A. Ensure the valve will open and close properly.
Operate and visually check that the valv
e
c
ompletely opens and closes (Figure 4.42)
.
D
epending on type of valve:
Ball Valves: ensure stops and indicators are
correctly set, or
Gate Valves: Count the number of turns requir
ed
t
o open and close the valve completely. Record
the number of turns on the Measurement Car
d
and m
easure the length of the stem above th
e
oper
ating handle in the open (Figure 4.43) an
d
c
losed position (Figure 4.44). Take note of thes
e
m
easurements.
Figure 4.42. Open and
Close Valve
Figure 4.43. Open
Position
Figure 4.44. Closed
Position
B. Leave the valve in the open position.
⚠
CAUTION
Do not use force when opening and
closing the valve. Use of force will
not improve the seal and can
damage the valve.