Pressure Testing of Valves

[Inchtain]

Good morning,

Can anyone give me clear steps for the following valve tests?

Low-pressure closure test

backseat test

Double block and bleed high-pressure closure test

I would appreciate it if you have videos explaining the procedures.

Additionally, is it a good practice to test gate valves through the packing gland and the bonnet of the valve while the gate is closed and both flanges are open?

Thanks

 

[Danlap]

Hi,

Please buy/subscribe/see at least API 598. The step cannot be any clearer than that.
Usually parties which commenced testing are only three: manufacturer, end user and third party testing companies. There are many reasons for them (better) not to post any videos.
Their reputation, tested valve quality dispute and various standards might have different acceptance criteria are only few of the reasons.
I sincerely doubt you will find any.

Regards,

 

[LittleInch]

Normally the vendor will give you a detailed testing procedure. Ask for it or find it. That will tell you a lot.

That last test I can't recall seeing before and sounds very odd. What exactly are you testing in that line? You want to stop fluids coming out usually, not inwards unless you're trying to test a vacuum rating, but easier to pull a vacuum on the valve.

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

 

[yldrmkara]

API 598 explains it very clearly.

 

[Vegas Consulting]

Good morning!

Here are clear steps for each valve test you mentioned:

1. Low-Pressure Closure Test​

• Objective: Checks for leakage at low pressure.
• Procedure:
  1. Close the valve.
  2. Apply the required low-pressure test fluid (usually air or water) to one side of the valve.
  3. Check for leakage on the other side of the valve as per the acceptable limits defined in API 598 or relevant standards.
• Acceptance: No visible leakage or as per the standard's allowable leakage criteria.

2. Backseat Test​

• Objective: Verifies the integrity of the valve’s backseat, usually on valves with a rising stem.
• Procedure:
  1. Open the valve fully to engage the backseat.
  2. Apply test pressure to the valve body.
  3. Observe the packing area for any leakage.
• Acceptance: No leakage around the packing gland area.

3. Double Block and Bleed High-Pressure Closure Test​

• Objective: Ensures the valve can hold pressure from both sides with a vent in the middle.
• Procedure:
  1. Close the valve fully and apply test pressure on one side of the valve.
  2. Open the bleed valve to check for leakage past the first seat.
  3. Repeat the procedure for the opposite side of the valve.
• Acceptance: No leakage from the bleed valve when pressure is applied from each side.

These tests are essential for verifying valve integrity and ensuring operational reliability. Following these procedures helps maintain safety and performance standards in line with industry requirements. For further guidance, video resources are often available on valve manufacturer websites or video platforms like YouTube.

Hope this helps!

Regards,
Vegas