Contact US

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.

Students Click Here

Isolation for Maintenance and Repair

Isolation for Maintenance and Repair

Isolation for Maintenance and Repair

Good day, forum

I have a question concerning safety precautions for process system (equipment and/or piping) isolation for maintenance or repair. When and why block valve(s), check valve, bleed valve, split plate (blind), spectable plate (blind), blank flanges are to be used and its combinations? When and why physical disconnection, squeeze off, foam bagging, pipe plug, freezing are to be used?

I know that ask much but I need documents - engineering practices and standards. The only suitable document I have found is HSG253. Can one provide with links to worth documents concerned?

Links to incidents and accidents statistics are welcomed.

RE: Isolation for Maintenance and Repair

Process Industry Practices (PIP) has many different standards and practices that you can reference. See the link below.


"Thinking is the hardest work there is, which is probably the reason why so few engage in it."

-Henry Ford

RE: Isolation for Maintenance and Repair

hsg 253 is pretty good as a guideline.

Most operators then develop and maintain an isolation philosophy relevant to their locations, fluids and perceived risks.

As these vary widely, then so do the agreed means of isolation.

Determination of where the specific items are applied is by the design engineers, typically the process engineers, using the philosophy which is then picked over by other disciplines including technical safety and then discussed in the HAZOP.

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

RE: Isolation for Maintenance and Repair

Isolation is one aspect. The second aspect is to trigger the equipment connected to the piping to ensure that there is no rediduals left in the equipment and piping.

RE: Isolation for Maintenance and Repair

I know you're looking for documents, but cost and speed of repair is of immense importance.

So for example, the cost to pump down a tank, clear the headspace of toxicity, confined space entries, and additional lost time could be easily estimated to justify shutoff/block off features in the wearing equipment. Keeping workers separated from hazardous areas too. That's pretty hard justification.

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! Already a Member? Login


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