Trunnion Mounted ball valve seat testing

[tusharpatil9983]

Hello,

I am seeking guidance on Hydrostatic seat testing. Currently, our testing procedure is as follows:

Step 1: Fill the cavity until water comes out from the vent port and then close the valve.
Step 2: Apply the hydrostatic test pressure from seat A (test pressure is 1.1 times the rated pressure).
Step 3: Observe the pressure on the gauge and visually inspect the vent port. (As cavity is filled if seat A is leaking then water will come-out of vent port)

I have two questions:
Is the above-mentioned test process in compliance with API 6D and API 598 standards? Or there is a different approach to inspect the hydrostatic test.
Following the above test procedure, we observed valve leakage visually (approximately 2-3 drops/5 minutes) from both sides individually. However, there was no leakage found in the Pneumatic seat test at 6 bar, and no leakage was found in the low-pressure Pneumatic seat test at 1 bar. How should we interpret these results to determine whether the valve is acceptable or not?

 

[JustABallValve]

To answer your question we need more information.

1. What type of valve is this? Soft seated?
2. Is the requirement API 598 or 6D?
For API 598 A hydro seat test is not required unless specified by the customer. Also in API 6D a low pressure seat test is not required unless specified by the customer per Annex H.