×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Pneumatic Testing against closed valves?

Pneumatic Testing against closed valves?

Pneumatic Testing against closed valves?

(OP)
Does someone know if we can pneumatic test against closed valves?

RE: Pneumatic Testing against closed valves?

Yes, several people know that.  Oh, would you like someone to provide the information you didn't ask for?  Sure, I can take a stab at it.

Generally, company policy controls.  Some companies prohibit it, some allow it, the vast majority are silent.  As far as I've been able to find, the codes tend to be silent.  Again, this one comes down to Engineering Judgement.

Few valves are truly bubble tight, so testing against a valve can cause a steady bleed off that looks like a leak (remember that in a pneumatic test, a leak looks like a spring slowly uncoiling instead of a rapid depressurization like you would see with a hydrostatic test).  If you are using air or nitrogen for your test media, you could easily cause serious process problems on the other side of the leak.

I always install skillet blinds on the test side of block valves.  You have to be REALLY careful to get the thickness right because it can be impossible to remove the wok you made by pressurizing a skillet that is too thin (the time I missed a decimal point we had to blow down a couple of miles of 12-inch line to drop the block valve to remove the wok).

David

RE: Pneumatic Testing against closed valves?

(OP)
You are good man! Thanks!

RE: Pneumatic Testing against closed valves?

David,

Were you able to sell the wok to an Asian food restaraunt later?

RE: Pneumatic Testing against closed valves?

No, the handle was too rough, but I kept in my "how stupid are you" collection until my office mate got sick of barking his knees on my rusting metal and he threw it all away (the prize of the collection was five 6-inch 90 degree elbows close coupled out of plane with a flange on both ends, pretty sculpture but very heavy).  The "wok" was about 13 inches across, about a 1/2 inch flange all the way around and 3-inches deep--a perfect chord of a sphere.

David

RE: Pneumatic Testing against closed valves?

API 598 requires a low pressure Air seat test for most gate valves. It's an optional test for Globes and checks.  That would be a pneumatic test on a closed valve.

RE: Pneumatic Testing against closed valves?

That is true.  I got the feeling that he was talking about a system strength test, but I could easily be wrong.  His original question was quite lacking in details.

David

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources