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

Smoke Test on pipelines

Smoke Test on pipelines

Smoke Test on pipelines

Hello all,

We are building a big system of thread lines acc. to ASME B31.3 and this lines will be service test with air. The last test that they carried out took 19 test to find and treat all leaks. Now we have a new similar project and in order to not spend all this time I heard about smoke test on threaded air lines. Here follow rhe premisses and my questions:
- 1" up to 2" pipes on carbon steel ASTM A106
- TEst pression will be not more than 15 bar (218 PSI)
- all system will be test once

- IS it possible a leak smoke test on this line?
- if yes, wich smoke generator should i use?
- Anybody here already made this test?

Sorry my english and i appreciate ever knowlegde that you can share!

thank you

RE: Smoke Test on pipelines

Never heard of smoke test for pressurised pipe.

Normally either soap bubbles around every joint or helium testing. - e.g. https://pipingtech.com/services/product-testing/he...

Once you find a leak you need to fix it then test again, so I'm not sure how you can only test once? But neither do I understand why the last one took 19 tests?

Big systems of threaded pipe are not great systems to build and test. Maybe try doing it in sections as you go?

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

RE: Smoke Test on pipelines

Little Inch offers good advice ...

Yes, like your MBA boss boasted, an all-threaded compressed air piping system will be easier and quicker to build with a large unskilled work force.

But there is an eventual price to pay with threaded pipe and there is a good reason that, here in the West these systems are mostly fillet or seal welded.

Threaded piping systems eventually leak and, although there are significant savings during installation, the owner will pay lots of money over the years for expensive compressed air leaks.

You will be better off building and testing your system in sections

I am betting on 12 - 16 retests

Somebody is indeed blowing smoke

Sr. Process Engineer

RE: Smoke Test on pipelines

There is no reply buttomz.
@Little Inch:
This sollution is usual to find leaks on cars engine or sewer systems e.g. https://youtu.be/2IpLABJw2KU; but a friend of mine already used to threaded lines in Italy.
I am looking for a good advice of smoke generator as https://www.boschdiagnostics.com/products/smt-300-... (actually i am not sure if i can use this machine). It took like 19 times due the soap bubble solution and when you tight one side of pipe, the other side gets loose. This is the main issue of threaded pipe service test and it is a big system.

The system was not design to be section tested, when i have arrived in this project i try to give them some advices and alocate valves and joint connections in section to avoid test all system again and again.

@MJCronin, the fillet weld is not possible due the pipes are galvanized, this sollution is really good, but now we can not seal all the threads, we have one week to carry out the tests.

Anyways i will try to buy a smoke generator, fill the system and close valve by valve until i get all system full of smoke and all valves closed. after that i will apply the pressure required and see if we can find the leak by looking without the soap spray... maybe i can develop a new way to test this systems.

Thank you for sharing!

RE: Smoke Test on pipelines

Eneias ...

Can you tell me where in ASME B31.3 that "smoke testing" is discussed ?

1) Is this a compressed air or compressed gas piping system ?
2) What are the piping materials and is the system galvanized Schedule 40 ?
3) "when you tight one side of pipe, the other side gets loose" .... Yup... that's why we like welded pipe
4) Any well-designed large distribution system should be designed with shut-off valves to isolate branches
5) Soap solution pressure testing is not expensive and your smoke indication system may not work.

and lastly .... Was your butt-hole MBA boss smoking a large expensive cigar when he assigned you this project

Give us more detailed information ... What exactly is the system and can you give design Pressures and Temperatures

I have changed my mind and am now betting on 14-18 retests

Sr. Process Engineer

RE: Smoke Test on pipelines


Thank you for your reply...

Actually this pre test is not discussed in ASME B31.3 but i suppose that can do it before the pneumatic test as a guarantee that everything will not leak.
I came from Oil and Gas industry and there everything is well thought before the tests; Now i face this weird situations and i am working in a mine iin europe...

1)Compressed air - instrument air system.
2) it is 1" up to 2" pipe - Galvanized - attached - we are not using A53 ERW but A106 Gr. B XS - https://files.engineering.com/getfile.aspx?folder=...
3) totally agreed
4)Agreed again (i did not design)
5)The soap bubble gets expensive when we have a lot of lheaders and brachs lines that has to be accessed by scafold, so if the pressure drops, we have to soap bubble every single thread to find out wich one is leaking, with the smoke test, we can see which thread is leaking. (i guess)

When they hired me 3 months ago were to implement some Quality habits were did not exist before. I came from Project manager (O&G) to Quality manager (Mines).´

I hope you 14-18 tests do not happens hahaha if i can use this smoke system i hope not more then 6 tests!!!!!!
my main issue is how long the smoke will keep as smoke after pression(?)

RE: Smoke Test on pipelines

smoke systems are only of use on very low pressure systems where you can literally blow smoke into a system and have some sort of throughput.

It's useless in a pressurised system test.

So you can test with smoke to find huge holes, but as soon as you the pressure it up with air or gas at maybe 10 bar, air will start to hiss out everywhere in your "tested" system. Not good.

But either way, you still find a leak whether soap bubbles or smoke, so you still need to fix it.

MJC may be a ornery old curmudgeon who hates people with MBA's, but he does talk some sense.

The fact that your contractors appear to be useless in installing screwed systems is not our problem - big screwed systems are not good long term in containing their contents.

Normally you use a lot of couplings to prevent one tightening becoming another loosening.

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

RE: Smoke Test on pipelines

If your issue is access to the joints then try the helium system as you can use extendable "wands" to check for leaks.

With smoke you will only see the really big leaks.

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

RE: Smoke Test on pipelines

Thank You LittleInch ...

Yes indeed, I am ornery, retired and old ...

... and when I have taken all my medications, gotten my night's rest and made a trip to the bathroom ...

I do occasionally make some common sense

Sr. Process Engineer

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