Installation, Operation and Maintenance Manual
SERIES T/TE/TW/TWE
ONE-PIECE TOP ENTRY
TRUNNION BALL VALVE
Page:
9
of
12
Document Name: IOM-T
Revision:
15333
Release Date: 06/26/2015
V.
Valves are to be substantially relieved of air
or gas when tested with liquid.
VI.
Seat closure tests are to be conducted
after acceptable shell test.
9.3) SHELL TESTING
Prior to painting or other external coatings,
Valves is to be subjected to a hydrostatic shell
test. There is to be no leakage under the test
pressure when both ends are blanked and ball is
partially open. Testing pressure is 1.5 times MOP.
Test duration are 2 min for 4” and under valves,
5 min for 6” to 10” valves, 15 min for 12” to 18”
valves and 30 min for 20” and larger.
I.
Fit the vent valve and set it in open
position.
II.
Operate the valve to the half-open position.
III.
Fill in the valve with the fluid (Venting the
air through the vent valve)
IV.
Close the vent valve and apply pressure in
accordance with max operating pressure of
the pipeline.
V.
Visually check the outside of the ball valve
for possible deformations or leakage.
VI.
Depressurize the valve.
9.4) HYDROSTATIC SEAT TESTING
Valves are to be subjected to a hydrostatic
seat test. There is to be no leakage under test
pressure. Test pressure is to be applied
successively to both sides of closed valve with
other side open to atmosphere. Testing pressure
is 1.1 times MOP. Test durations are 2 min for 4”
and under valves, 5 min for 6” and larger valves.
I.
Operate the valve to the fully close position
and open the vent valve.
II.
Pressurize one side in accordance with max
operating pressure of the pipeline.
III.
From the body vent, check for possible seat
leakage.
IV.
Repeat same operations as per points 2 & 3
on opposite side of the valve.
V.
Depressurize the valve.
Note:
For valve without a body vent or drain
connection, it is necessary to install a control
system on the pipeline to measure the pressure in
upstream and downstream of the valve.
9.5) SUPPLEMENTAL AIR SEAT TEST
Valves subjected to an 80psi air seat test shall
show no signs of visible leakage.
9.6) DOUBLE BLOCK AND BLEED (DBB) VALVES
If the valve has DBB, the test shall be
performed as follows:
I.
With the valve in half-open position, the
valve shall be completely filled.
II.
The valve shall than be closed and the
valve vent opened to allow excess fluid to
overflow from the cavity connection.
III.
Apply pressure on both the seats
simultaneously.
IV.
Seat tightness shall be monitored from the
cavity connection.
V.
Depressurize the valve
.
Note:
For valve without a body vent or drain
connection, the above test is not applicable
