New gas line – pressure test – how long?

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dave1977

Hello
My contractor recently installed new gas pipe from new gas meter (external front wall of house) to the kitchen (inside house at back of house – 8m long). The gas pipe is currently in view (waiting for under floor heating to be installed). I wanted the gas pipe tested under pressure (9 bar) before under floor heating is laid.

The contractor got the plumber to insert a device to test the pressure but he only checked the pressure for 2 seconds and then said there is no leak. We said surely it had to be left for longer but he said this is standard practice and only a few seconds is necessary. The gauge did not move from 9bar for 2 seconds. Is 2 seconds sufficient? If not how long should the pressure gauge be left for?

Thanks
Dave
 
personally i would have left it longer than 2 seconds but i wouldnt have tested at 9bar for a pipe thats got to work at around 20mb
im pretty sure at nine bar thats roughly 125psi you would have heard or seen any faults
8m is probably three joints in floor?
 
Last edited:
stevetheplumber said:
personally i would have left it longer than 2 seconds but i wouldnt have tested at 9bar for a pipe thats got to work at around 20mb
im pretty sure at nine bar thats roughly 125psi you would have heard or seen any faults
8m is probably three joints in floor?
Click to expand...


hello
there are approx 3 bends..

dave
 
Why may I ask are you wanting this tested at 9bar? A tightness test takes 4 minutes and is tested at a pressure of approx 20mb. You meter should only put out 21mb +/- 2mb. Tightness test as follows. 1 min let by at 10mb. 1 min at 20mb stabilisation and two minutes at 20 mb tightness test. You are allowed a 4mb drop at an appliance however, if on the pipe it is an immediate fail.
 
new pipe work no drop allowed why do you want it tested at 9bar ? think its the heating pipe work that needs 9 bar.
 
Heating pipework should not exceed 3.5 bar.

Why did you want the gas testing at 9 bar?
 
DuncanM said:
Why may I ask are you wanting this tested at 9bar? A tightness test takes 4 minutes and is tested at a pressure of approx 20mb. You meter should only put out 21mb +/- 2mb. Tightness test as follows. 1 min let by at 10mb. 1 min at 20mb stabilisation and two minutes at 20 mb tightness test. You are allowed a 4mb drop at an appliance however, if on the pipe it is an immediate fail.
Click to expand...

Same here, new install pipe only, cap end on and standard tightness test.
 
Silly question really but is your gas contractor GSR?
If so he/she would know the correct testing procedure and pressures.
 
If you have put 9bar thru a copper pipe that is only to be used as a gas pipe I would say that you have potentially damaged the pipe.

Standard domestic copper is only rated to 10bar. And you may have locked any dry joints into place. Meaning that they could possibly not leak at 9 bar. But may leak at 20mBar

My advice would be to use trac pipe to reduce the amount of fittings. And in the commercail world the highest we test this 4x working pressure.

This is ridiculous !
 
totally excessive pressure test. one issue can be if using a compressor to test up to 9 bar you would'nt actually notice a 2mb drop as it would be difficult to see on a gauge that reads in 1 bar increments. as said previously total test time of 4 minutes at 20mb.
 
The only time i know of that a gas supply pipe should be exposed to any way near that pressure is when pre-testing commercial gas pipework. prior to a tightness testing a strength test must be calculated taking into consideration the system volume, working pressure and materials even then the test pressure would never usually exceed 21mbar or in some circumstances 40mbar.
My only other worry with regards to testing at such high pressure is potential damage to the gas meter, modern meters both diaphram and electric are very fragile and the workings should be treated with care.
 
adam84 said:
The only time i know of that a gas supply pipe should be exposed to any way near that pressure is when pre-testing commercial gas pipework. prior to a tightness testing a strength test must be calculated taking into consideration the system volume, working pressure and materials even then the test pressure would never usually exceed 21mbar or in some circumstances 40mbar.
My only other worry with regards to testing at such high pressure is potential damage to the gas meter, modern meters both diaphram and electric are very fragile and the workings should be treated with care.
Click to expand...

I'd read your commercial books again. Standard strength test is 84mb
 
There is obviously a misunderstanding here - 9 bar is nearly 5 times the pressure in ya car tyre
 
Strength tests have no standard test figure requirements, each installation must be calculated individuly this 84mbar figure you offer may be for an air based strength of some description but when testing buy hydrolic means these pressures can be much higher, to test an 8" screwed steel installation with over 70 meters of pipework 84mbar wouldnt show any weakness due to the volume of the pipework.
 
The STP is determined by the MOP or MIP. It has little to do with pipe sizes or volumes. On a std low pressure supply the MIP will be 75mb. STP will be 1.1 x MIP which in this case is 82.5mb. Test duration (for any size pipe) is 5 minutes stabilisation + 5 minutes test. 20% pressure loss is allowable with a pneumatic test and 5% if hydrostatic testing.

On bigger systems at higher pressures (again any size pipe), if the MOP is say 2 bar the STP would be 2bar x 1.5 = 3bar tested for 10 minutes stabilisation plus 5 minute test with the same drops allowed.
Taking it to the extreme with a MOP of 16bar the STP is 16 x 1.5 = 24bar. Hydrostatic test only, stabilise for 30 mins test for 30 mins with a 5% allowable drop.

(IGE/UP1)
 
Testing a gas pipe thats going to be buried at 20mb is a waste of time flux will hold that sort of presure id give it 3bar and 10 mins for my own peace of mind
 
This sounds like a case of the blind leading the blind..!!!

Who determined that the test pressure should be 9 bar and on what basis was such a decision made?

What sort of guage was used to measure this test pressure and how was any pressure loss or indeed,rise discerned?

What atmospheric correction employed?
 
is this the gas forum lol never heard so much rubbish, 9 bar test dont forget the safety cage
 
Why would a GSR engineer take the advise of a customer about how and what pressure to test a gas carcus??

where did 9 bar come from?
 
If it was either eight or twelve bar then I could accept that it's based on The Blues, never tried nine bar tho.
Where's my guitar!
 
Did he use a foot pump?
 
As said before in posts a new installation should be tightness tested from meter test point and no drop allowed.Why he tested at extreme pressures is beyond me
 
I think that this thread was an April Fool windup.
Only two posts from OP now he's disappeared.
(or visiting nine bars)
 
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