×
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

Use of relief valve discharge covers/caps required?

Use of relief valve discharge covers/caps required?

Use of relief valve discharge covers/caps required?

(OP)
We typically install weathercaps to prevent snow/ice/bird nests, etc. in the discharge of relief devices as well as install the discharge piping with a weep-hole or drain.

I cannot find any reference to caps being required but have seen many on LPG storage tanks etc.

Is this a good design practice or does anyone know of code type requirements?

RE: Use of relief valve discharge covers/caps required?

In the past I worked for a client that wanted to have the caps on relief valve outlet to see whether the relief valve had blown. This was for a not normally manned facility, so the caps were used just to know which valves needed to be overhauled. I remember that these valves were all provided with weepholes.

For an LPG sphere something similar could be valid. They are usually located remote from the main facility, so that it is possible that a relief valve would blow without anyone noting it.

When following this logic, the relief valve with cap would still require a weep hole, since relief valve could be there for some time before someone noting that the cap has blown off. In that case, weep hole would still prevent accumulation of liquids...

RE: Use of relief valve discharge covers/caps required?

BenThayer:

I don't know of any API or ASME mention of a restriction on caps (plastic?) being used on the discharge nozzle of a PSV.  I've used hinged metal covers on PSVs to resolve what you describe as a deterrent to a clogged discharge nozzle.  I would take care to make sure the cover (or cap) cannot bind, stick, or rust itself in the closed position and that has always bothered me.

I also used a weep hole with the hinges; I felt much better with the "belt and suspenders" philosophy in this case.

Art Montemayor
Spring, TX

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