×
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

Re-testing frozen process pipe systems
2

Re-testing frozen process pipe systems

Re-testing frozen process pipe systems

(OP)
I am trying to determine if there is a code requirement within B31.3 to re-test piping that had been frozen subsequent to hydrotest. I have performed visual examinations and do not see any deformations.

RE: Re-testing frozen process pipe systems

2
If you froze a pipe you may way to do some diameter checks to make sure the pipe hasn't dilated significantly.  Especially look near any restraints (supports, vents, drains, tees, etc).

Even if you find some dilation, you could probably apply the general 1% rule for out of roundness from most construction codes.  If you need to go beyond that have a look at API 579 using the bulging rules and aim to keep the local plastic strains below 5%.  

I have, in the past, done another hydro to check the pipe, more for a flange leak check, etc.  As long as there is no gross distortion, then a hydro says you still have reasonable properties and you are good to go.

Hope that helps...

Ryan

RE: Re-testing frozen process pipe systems

Interesting thread, I've never looked at API579 for this.  

I would wonder if by freezing the pipe and expanding it you end up , pardon the pu, cold working it? I wonder if the metalurgist fourm might be a better resource.

And as always my story.  I was rebuild a plant when we came across a bypass line in a wet natural gas service.  The bypass dropped straight down, under ground came back up through the bypass valve and into the line.

We had to dig around the by pass line and exposed it.  All the coating was broken in longitutanl orientations.  We measured the od at 8.7/8 inches to 9.0 inches.  The water would drop into the bypass line and sit there and freeze.

I just replaced with a slightly off level bypass.

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