Hydro test acceptance acc. to API 6A

[R.Eng]

Hi,
What is the acceptance criteria for hydrostatic testing of gate valves according to API 6A?
We see some points like dew on the surface of gate.Is it acceptable? Can we consider it as leakage?
The surface of gate and seat is WC coated.

 

[LittleInch]

Usually leak testing is with gas and you count bubbles or measure gas quantity.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[LittleInch]

Hydrotesting is monitor pressure.

That sounds like condensation.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[R.Eng]

How can we distinguish between condensation and leakage?

 

[LittleInch]

Doesn't matter.

Hydro test is a strength test of the shell. You shouldn't be leak testing against the gate - for that you normally use gas and liquid so that you can see the bubbles.

look at 7.9.4.3.3 States don't test across the closed element and leave valves partly open.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[R.Eng]

Please take a look at these paragraphs:

11.2.4.2 Test Method—PSL 2, PSL 3, and PSL 4
For PSL 2, PSL 3, and PSL 4, the following shall apply.
a) The general requirements of 11.1 and 11.2.1 shall apply.

b) Hydrostatic test pressure shall be not less than the rated working pressure of the valve. Pressure shall
be applied through one side of the flow bore to the closed gate, ball, or plug of the valve, with the other
side vented to atmosphere. Unidirectional valves shall be tested in the direction indicated on the body,
except for check valves, which shall be tested from the downstream side.
c) Pressure shall be monitored for the primary hold period specified in Table 32, as a minimum.
d) The valve, except for check valves, shall be opened while still under full differential pressure. For PSL 3
and PSL 4 only, the operating input required to open the valve while operating under full differential
pressure shall be measured.
— For manual valves, the operating input shall be torque.
— For valves with hydraulic or pneumatic actuators, the operating input shall be pressure.
— For valves with electric actuators, the operating input shall be current.
NOTE 1 Measurement of torque or actuator input is not required for PSL 2.
e) Test pressure shall be applied a second time to the same side of the gate, ball, or plug.
f) Pressure shall be monitored for the secondary hold period specified in Table 32, as a minimum.
g) The valve, except for check valves, shall be opened a second time while still under full differential
pressure. For PSL 3 and PSL 4 only, the operating input required to open the valve while operating
under full differential pressure shall be measured.
— For manual valves, the operating input shall be torque.
— For valves with hydraulic or pneumatic actuators, the operating input shall be pressure.
— For valves with electric actuators, the operating input shall be current.
h) Test pressure shall be applied a third time to the same side of the gate, ball, or plug.
i) Pressure shall be monitored, and the valve shall be monitored for visible leakage, for the tertiary hold
period specified in Table 32, as a minimum.
NOTE 2 Methods other than direct observation of the valve bore sealing mechanism may be used for visual leak
detection, provided that the visual monitoring method has been validated to show fluid leakage when present.
j) Test pressure throughout the valve shall be reduced to 0 psig.
NOTE 3 The valve is not opened under differential pressure after the tertiary seat test.
k) For a bidirectional valve, steps b) through j) shall be performed on the other side of the gate, ball, or plug
using the same procedure outlined above

 

[jbeckhou]

are any parts being hydro-tested made from a casting?


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