Pressure testers (advice please)

[finchy01]

I've never bothered with pressure testing before because my soldering is normally pretty good. I'm currently doing a full system from scratch though and the builder got all the materials. Bar the tails the whole lot is in barrier and I'm not happy with a lot of the joints. I have a horrible feeling it's going to sound like the 1812 overture with joints popping everywhere. I therefore popped out today and grabbed a Stanley compressor but think I'm going to have to adapt the hose end to fit a bit of 15mm. Has anyone used these or the proper rothemberger hand one? It's only 8 dads but I don't fancy sitting there with the rothemberger one pumping away for an hour to pressurised it. Any experience you have with either of them would be welcomed. Ta.

 

[Scott_D]

Water test or air?

 

[ShaunCorbs]

Can't do air past 0.5 bar sorry to say time to pick up a water test kit

 

[townfanjon]

I have the REMs one , for cirtain jobs, I wouldnt be without it .

Could you hire one if you dont fancy investing

 

[Allgoode]

As above don't do air above 0.5 bar, there's a lot of stored potential energy in a charged system should anything blow off.
With water fill & bleed first before connecting in rothenberger water rig to pressurise system.
Cheers,
Andy

 

[finchy01]

Wow. Thanks for the rellies. The couple of times I've seen other plumbers doing it when contracting they've air tested it upto 4 or 5 bar using a compressor. I was just going to crack on and do that. Sou d's lime that's not a good idea! I was under the impression the rothemberger one was air too just hand pumped.

 

[steadyon]

Some of the plastic pipe / fittings manufacturers expect a pressure test at 10bar (or more) for around 45 minutes. In part this is to make sure the grab rings bite into the pipe.

You cannot safely pressure test this with air for the reasons mentioned in earlier replies, i.e. the huge potential energy stored in compressed air. It needs to be done with a hydraulic (water) test. Fill the system with a hosepipe to avoid excessive pumping, then increase and monitor pressure with something like a Rothenberger RP50.

 

[Stigster]

+1 for the RP50. I use one several times a day which is surely more than any plumber out on site would use it and we get about 3 years out of one before needing to replace any washers or seals. Even if it was used once a day such a pump should last many years.

 

[AWheating]

Imagine the pipe work being a very large air gun and a fitting being the bullet and you get why it's a bad idea. Hydro test, can get a rp50 copy from eBay for about £40-50

 

[HoodedClaw]

Well, never knew air shouldn't go over 0.5. I only use air, on a new system shut off rad valves and test pipes only first - 1/2 to 1 bar gets any dodgy connections hissing and it's not enough to pop any. once they are sorted I'll take it to 3 and leave. If thats ok - wet fill and test again. No compressor, just track pump, doesn't take long.

Only bullet I've seen is when training and someones work was mains tested, it hit the warehouse ceiling.

 

[Jerry]

+1 for the RP50. I use one several times a day which is surely more than any plumber out on site would use it and we get about 3 years out of one before needing to replace any washers or seals. Even if it was used once a day such a pump should last many years.

What r u doing all day????????

 

[Tim S]

Cap off the rad tails (no point filling all the rads to test the pipework) then pressure up the pipe work using the RP50...doesn't take too long, there's not that much water in the pipes. Leave it on test for as long as you feel the need..you can wet vac any water out of the pipework if necessary ...don't air test...you can't compress water...but you can compress air !!!

 

[AWheating]

Those that air test I assume you have specific public liability insurance for it? I assume you barrier off, use warning signs to keep the building clear?

My old company had risk assessment and method statements for air testing. If you read them you wouldn't bother trying.

 

[OffshoreGas]

Can't do air past 0.5 bar sorry to say time to pick up a water test kit

Don’t see why you couldn’t/shouldn’t complete a reinstatement test using air. You just need the right controls in place. Empty the house, take it up in stages. Run your compressor in a safe area. Plant air systems routinely run at 10bar, your talking about L’s of capacity in a system especially if you isolate the rads.

 

[ShaunCorbs]

Don’t see why you couldn’t/shouldn’t complete a reinstatement test using air. You just need the right controls in place. Empty the house, take it up in stages. Run your compressor in a safe area. Plant air systems routinely run at 10bar, your talking about L’s of capacity in a system especially if you isolate the rads.

It’s bs spec if you do pipes needs to be sandbagged and whole house needs to be emptied

 

[OffshoreGas]

Those that air test I assume you have specific public liability insurance for it? I assume you barrier off, use warning signs to keep the building clear?

My old company had risk assessment and method statements for air testing. If you read them you wouldn't bother trying.

Don’t really see why you’d need specific public liability insurance?

Everything we do should have a suitable risk assessment and controls in place. Test it in sections if possible and take sensible precautions like you suggest.

It would be down to the insurance underwriter to explicitly forbid pressure test by air wrt liability insurance.

 

[OffshoreGas]

It’s bs spec if you do pipes needs to be sandbagged and whole house needs to be emptied

A British standard isn’t a legal requirement it’s a best practice document. So long as you can demonstrate you’ve put adequate controls in place and used sound engineering you can deviate from this however you wish.

 

[ShaunCorbs]

A British standard isn’t a legal requirement it’s a best practice document. So long as you can demonstrate you’ve put adequate controls in place and used sound engineering you can deviate from this however you wish.

Anything goes wrong tho

 

[OffshoreGas]

Anything goes wrong tho

In truth so long as you go up in

Anything goes wrong tho

I'm with you, if it were me I'd take the whole lot up to working pressure with the mains and then another 50% with a hand pump.

At the same time I've service tested 18" RTJ natural gas lines the operate at 600bar and nitrogen/helium leak tested systems to nearly 1000bar without water because they had to remain dry.

If you've competently risk assessed the job and all identified controls are in place what can really go wrong?

 

[ShaunCorbs]

Surprised they didn’t test with water and then heat/burn it off

I bet that expanded a bit

In theory not much but it’s the surprises

 

[Jerry]

1000bar

Hell no! You can keep that! 200bar in a scuba tank is scary enough....

 

[OffshoreGas]

1000bar

Hell no! You can keep that! 200bar in a scuba tank is scary enough..

It's actually quite an involved/interesting process. You tape up evey flange/joint you want to test. Then use liquid nitrogen and pump skids to turn it into a gas and compress. Then you add a trace amount of helium (because there small atoms) and use a sniffer to detect the helium.

You obviously don't go from 0 - 1000bar in 10 mins, you probably go to 10, 50, 100 250, 500, 750, 1000.

If at all possible you'd always pre fill the test envelope with water but sometimes you can't for a range of reasons.

 

[Jerry]

It's actually quite an involved/interesting process. You tape up evey flange/joint you want to test. Then use liquid nitrogen and pump skids to turn it into a gas and compress. Then you add a trace amount of helium (because there small atoms) and use a sniffer to detect the helium.

You obviously don't go from 0 - 1000bar in 10 mins, you probably go to 10, 50, 100 250, 500, 750, 1000.

If at all possible you'd always pre fill the test envelope with water but sometimes you can't for a range of reasons.

Wow. My ignorance of anything outside of the domestic market is huge. Are we talking about huge industrial works and off shore oil rigs? Or is this everyday work in the UK?

 

[ShaunCorbs]

ofshore / under the sea prob or pet chem plants

com nornally you dont go over 10 bar

 

[OffshoreGas]

Wow. My ignorance of anything outside of the domestic market is huge. Are we talking about huge industrial works and off shore oil rigs? Or is this everyday work in the UK?

These aren't normally pressures you choose to work with, it's generally where something is coming up from a gas/oil well or your pumping it back down. You'd reduce these pressures as quickly as possible due to the obvious danger. Some chemical processes are at very high pressures but I've not personally seen any over about 300bar.

Gas pipelines are a trade off, the smaller the flow line the thinner the wall can be to contain a given pressure. The more you compress a gas the more volume you can fit down a given size but the thicekr the walls need to be.

A lot of the UKs gas comes in via pipelines but LNG is increasingly adding to the mix. Huge bulk carriers moor at buoys miles offshore and discharge via pipe lines to plants designed to return them to gas.

Not sure what pressure Transco run their network at but I believe its in the 8-10n bar range.

There are dozens of pipelines that crisscross the UK taking fuel to airports and road fuels for distribution to filling stations. These pipelines are generally 25 - 75bar ish in my experience.