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

Hot work safe distance from live plant

Hot work safe distance from live plant

Hot work safe distance from live plant

Hi all

I have been asked to commission a tank and am concerned about future work on site. They will be continuing with hot work a little distance from the tank while the tank has been commissioned (though it will be a different system). I haven't been to this particular site yet so the distance is currently unknown. Is there any rule of thumb for the distance you should be before it can be considered a safe area and a hot work permit would no longer be required?


RE: Hot work safe distance from live plant

This is really a site operations and permit policy decision, but as a start point, the safe area / hazardous area calculations undertaken by the electrical codes are probably the best way to start. However these only cover normal operations and for tanks there is no specific distance but depends on the contents, venting arrangements, location of flanges, valves etc

In my experience, anything inside a plant which constitutes hot work still needs a hot work permit, but when issuing and approving, the location will clearly govern whether it is permissible or the amount of precautions required. Normally a gas detector is required on permanent duty to warn of a gas cloud arriving as a result of some abnormal operation or occurrence (leak, rupture, spillage etc) occurring elsewhere, when hot work needs to be immediately extinguished together with cooling or extinguishing equipment.

If you are commissioning a tank then during that operation and afterwards, it then makes that part of the plant "live" and may change the permit requirements. It is often difficult on a new plant to get everyone to recognise that things change once you introduce hazardous substances when they have become used to not thinking about those things, but this is the responsibility of operations / construction management IMO to implement new rules as things change.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

RE: Hot work safe distance from live plant

Thanks LittleInch. I figured it would probably have something to do with the electrical zone ratings, was hoping for a "20m from pumps" kind of an answer :) They didn't do zone classification for this plant - working in Africa is veeeery different....

RE: Hot work safe distance from live plant

Ummm, it should still be designed by someone otherwise what sort of electrical equipment do they have and working in a plant without a work permit system when it's live is a bit beyond the pale...

As it depends on the substance, pressure, type and size of vent / flange it all needs to be calculated, but normally 10 to 15m max from any potential leak source (flange, relief valve vent, pump etc should be a good start point. For tanks it depends on the vent arrangement and whether the vapour is lighter than air or heavier....

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

RE: Hot work safe distance from live plant

It's gasoil & mogas...

I am not sure if it was designed properly, though I know everything is EX except motors are IP56. Thanks for the help though!

Will definitely have to see if they are even using work permits o.O Hopefully they are. But I know it's so remote that they don't have water to hydrotest, and generally when it's remote, safety standards are not as they should be.

RE: Hot work safe distance from live plant

You seem to keep mixing "hot work" - which in construction and repair is "work that creates an explosive/flamable reaction" such as welding, grinding, arc cutting, plasma work, and gas-fired heating (postweld heat treatment with thermal blankets (although "hot") is not considered flame-producing usually) - with electric motor design and operation.

Unless the motor is sparking, construction (commissioning of the tank, other fabrication around the tank) doe not usually consider electric motor operation hazardous. Oil and refinery operations of course, need special electric motor rules and reg's to avoid just that sort of ignition of the vapors around the refinery.

Every OSHA construction site is required to monitor its own hot work rules and processes. Once your tank is built, installed to the pipe network, and the red tags are released to turn the tank back over to operations, the plant needs to re-set its hot work permit process around the "new tank" as required.

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


Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

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