New gas line – pressure test – how long?

[rashik1977]

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

 

[sherbert]

Are you sure it was 9bar

Think you maybe mistaken

what the hell did he use to get the pipework to that pressure

 

[Dan Robinson]

He probably saw you as a wind up merchant and duly obliged.

 

[kevindgas]

Are you sure it was 9bar

Think you maybe mistaken

what the hell did he use to get the pipework to that pressure

I pressure test pipework at 8bar using an air compressor not that uncommon. test for 2 minutes though not 2 seconds.

 

[ollski]

That sounds like the sort of tests my brother does on his industrial hard copper oxygen line installations, certainly going to be putting silly stress on a domestic install.

 

[45yearsagasman]

Why on earth would you test a domestic gas line at 8 or 9 bar. Totally over the top.

 

[Homesafe]

That does'nt sound right to you and you're right it is'nt.

It should be tested at less than that but for longer, I'm sure someone will confirm that and give more accurate info.

 

[Boilerman2]

Air or Nitrogen Gas should NOT be used on a gas supply pipe at anything like 9 Bar, a catostrophic failure at that pressure could be very dangerous even fatal!! That is why pressure testing at high pressure is carried out using WATER as the test medium (water cannot be compressed, so if a failure occurs there is little kinetic energy and the situation is wet, not dangerous. However given that you will now have filled a gas pipe with water you would need to vacuum down the pipe work for a time period to evapourate the water from the system all very lengthy!

Gas Regs give specific guidence on Strength testing which uses a very low pressure if your installer is a RGI he or she should know all of this

 

[dreadnoughtheating]

Perhaps 9 bar helps to get the teeth on the push-fit fittings to grip tighter?

Just my 2mb worth.

DH

 

[plumbswe]

Perhaps 9 bar helps to get the teeth on the push-fit fittings to grip tighter?

Just my 2mb worth.

DH

Hahaha

 

[plumbswe]

On water its one and a half times the maximum working pressure. On gas its...? I dont know and can't find anything in my books...

 

[gaswizzard]

Perhaps 9 bar helps to get the teeth on the push-fit fittings to grip tighter?

 

[dcawkwell]

Air or Nitrogen Gas should NOT be used on a gas supply pipe at anything like 9 Bar, a catostrophic failure at that pressure could be very dangerous even fatal!! That is why pressure testing at high pressure is carried out using WATER as the test medium (water cannot be compressed, so if a failure occurs there is little kinetic energy and the situation is wet, not dangerous. However given that you will now have filled a gas pipe with water you would need to vacuum down the pipe work for a time period to evapourate the water from the system all very lengthy!

Gas Regs give specific guidence on Strength testing which uses a very low pressure if your installer is a RGI he or she should know all of this

Air conditioning systems regularly run at 9 bar and even higher pressure
without any particular risk.

 

[dcawkwell]

I would have said a standard drop test would be perfectly okay.

2 minutes stabilisation
and
2 minutes drop test at 20mb

 

[sherbert]

Are you sure it was 9bar

Think you maybe mistaken

what the hell did he use to get the pipework to that pressure

I pressure test pipework at 8bar using an air compressor not that uncommon. test for 2 minutes though not 2 seconds.

Why??

Cannot see any reason for testing at that pressure on domestic installation and as had been said the kinetic energy involved is huge .... do you have any idea what damage you could do if the pipe fractures ... obviously not
I assume that your just a domestic installer that has no idea about carrying out risk assesstments into your testing
Crazy doing this ... all thats required is to carry out a test as per normal for any gas install and prehaps carry out after the job has been screed if your worried about movement etc

Not that uncommon!! ............... can you tell me where it says to test to this and could anybody else come forward thats done this on a domestic install