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Anonymous Poster

Leak Test for Impulse Tubing

09/04/2009 2:30 AM

Hi all, This is Usman !

I am nowadays working at the construction site of ammonia plant (for fertilizer production), we are at the pre-commissioning stage and we haven't decided on a reliable standard procedure for the Leak Test for the Instrument Impulse Tubes.

Can anyone kindly refer me to a standard procedure which we can use at our site for LEAK TESTING OF INSTRUMENT IMPULSE TUBING. Our subcontractor is CNCEC (Chinese National Chemical Engineering Company) and their presented procedure is not impressive and has a lot of language barriers in it.

Thanks in advance

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Guru
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#1

Re: Leak test for Impulse Tubing

09/04/2009 6:51 AM

What is in the tubes, at what pressure and temperature, when the plant is supposed to be running?

What is the size of the tubes?

What are the tubes made of?

What are their maximum ratings as supplied as regards pressure and temperature?

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Associate

Join Date: Sep 2009
Location: United Arab Emirates, Abu Dhabi
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#2
In reply to #1

Re: Leak test for Impulse Tubing

09/04/2009 12:20 PM

Lets consider the case of instrument air tubing for control valves,

The tubing is 316LSS and size is 12mmODx1.0WT and it is a Seamless stainless tube.

Any standard procedure for their leakage test ???

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Active Contributor

Join Date: May 2009
Location: Ontario, Canada
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#3
In reply to #2

Re: Leak test for Impulse Tubing

09/05/2009 10:41 AM

I/A is not impulse tubing.

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Active Contributor

Join Date: May 2009
Location: Ontario, Canada
Posts: 21
#4
In reply to #2

Re: Leak test for Impulse Tubing

09/05/2009 10:42 AM

They still require leak test??? I've never encountered this, usually only on impulse line for transmitters.

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Associate

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Location: United Arab Emirates, Abu Dhabi
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#5
In reply to #4

Re: Leak test for Impulse Tubing

09/06/2009 7:56 AM

For control valves, instrument air tubing is leak tested as standard. The air headers & branches for instrument air are all tested as well the instrument air tubing from the branch to the valve.

The function of impulse tube and instrument air tubing are different but they are nevertheless tubings which require fitting and leakage test as well.

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Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

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#6
In reply to #5

Re: Leak test for Impulse Tubing

09/11/2009 11:54 AM

Please describe a procedure for the benefit of the orignal poster, as well as the rest of the forum.

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Anonymous Poster
#7

Re: Leak Test for Impulse Tubing

11/07/2009 9:18 AM

Better way to check the leakage in instrument air tubing of a C/V (which you call impulse tubing) with soap solution.

Pass air thru the line, apply soap solution over the joints & observe the leakage.

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Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
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#8
In reply to #7

Re: Leak Test for Impulse Tubing

03/11/2024 12:25 PM

That might work below 250Bar-litres, though it would be a very hazardous procedure above that. If passing above this point please ensure that all other CR4 readers are standing decent distance away before carrying out the test.

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Anonymous Poster (1); InstrumentKyle (2); PWSlack (3); Usman Nazar Rathore (2)

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