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!

*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.

Jobs

coating for bare pipe at supports

coating for bare pipe at supports

(OP)
Posted this on a Linkedin group, no response so trying here.
According to one article from a pipe support vendor, corrosion under bare carbon steel pipe at resting supports is initiated when the coating degrades from sitting in contact with trapped moisture for long periods. So even when resting on a non-metallic isolation pad, the mechanism is still there, and may in fact be worse than sitting on steel as the pad indents and traps more moisture.
So the question I have is, why not apply an immersion grade coating system at pipe supports, and for a short distance either side? This could transition back to a standard zinc epoxy system for the rest of the pipe. Isolation pads would be used at supports to prevent the coating from wearing off.
I'm interested to hear what coating specialists would say about this approach (economics, practicality), and if its been done before. I'm aware there are various other approaches such as I-rod, clockspring wrap etc.

RE: coating for bare pipe at supports

IMO, the non-metallic isolation pad may cause a maintenance issue if damaged. I saw the use of the metallic pad to protect the thin wall pipes in contact with support. I think there is not a perfect coating system to prevent it from damage, and it's a maintenance issue for the operation after years of service.

RE: coating for bare pipe at supports

Why not? No reason not to. Just make sure the coating you use is UV resistant, or put a topcoat over it (though not a bid deal as your corrosion control coating is still underneath). If you apply epoxy coatings over epoxy or some sort of paint, it is difficult to get them to adhere to each other, you will need to roughen the surface first. I prefer using some sort of composite wrap, it helps if there is an abrasion issue (between pipe & support). Its all what you make it, most don't as in projects coating is an afterthought, many just try for the easiest & cheapest, once turned over to operations its their problem.

RE: coating for bare pipe at supports

An immersion grade coating will buy you some time, but the corrosion fundamentals of the arrangement won't change - it's all about the crevices.

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/pub/8/83b/b04

All answers are personal opinions only and are in no way connected with any employer.

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


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close