Permissible drop and TT

[kirkgas]

Just to start a wee debate cause the telly is crap, this came up in college and caused a few comments,the scenario is: existing system existing appliances U6 meter, 22mm pipe, 2mb drop over 2 mins, no smell, no issues etc
The question is "MUST YOU ISOLATE THE APPLIANCES TO CONFIRM IF THE LEAK IS ON THE APPLIANCES AND NOT THE CARCASS SO YOU CAN LEAVE IT"
I want your opinion on what you must do, NOT on what you think is better, eg some say its better to isolate the appliances to confirm its not on the pipes,
My interpretation from IGE/UP/1B is
new install with or without appliances or existing install with no appliances then no drop allowed, or if the installation is existing with existing appliances and the drop is less than the table max permissible drop then the installation passes the test, therefore no further action required
Discuss

 

[Atouchofgas]

I was taught, that as everything is existing and it's within the permissible tolerances then no further action is required

 

[Mike Jackson]

I agree with that interpretation but you've got to be careful if replacing an appliance because you need to prove that the drop is on another appliance so that when you carry out the test when you finish work you know what the drop is on the old pipework and appliances. Aguy working for the same firm as me got RIDDORed for leaving a leak after a job. He tested detected a permissible drop, changed the boiler and tested again. The drop was the same so he assumed it was safe. Customer smelt gas over the weekend and called Transco out who found a leak on the meter unions where he'd removed it to solder, The drop had been on the old boiler and the leak on the meter unions was coincidentally the same as the dop on the old boiler.

 

[jase158]

I got taught that you must isolate as there is NO permissible drop on pipe work. How do you know whether it is on pipework or appliance unless you isolate the appliances?

 

[lame plumber]

once you isolate the appliances and prove the pipe work is leaking youve made yourself a problem! if the appliances are on it and it drops within limits and no smell , no problem, but its your choice then if you want to leave a leak. I hate leaks and normally hunt them down, hobs are main problem, meter compression joints becoming an issue and poor solders are common as well

 

[jase158]

once you isolate the appliances and prove the pipe work is leaking youve made yourself a problem!

better then going to prison for 5 years for manslaughter though!!

 

[Billy Bob Bob]

no permissible drop on the carcass,if isolating appliances still shows a drop ID,personally lame i dont care if it makes me a problem it means i have found something that could blow up a house and take life

 

[lame plumber]

therules give you some leeway and there are minor drops that can be impossible to find. My favourite leak was with an ex BG engineer who laid gas mains for years, he installed his own cooker and i was called in 22 years later after transco had cut him off. I could smell the leak in the hall and he pointer to the cooker which I got behind to find an unsoldered elbow. His comment was, it isnt worth the bothor boy, you have seen a leak till you seen a cracked main ****ing gas🙂, and the firemen hiding behind their red toy

 

[Keefy]

My answer to that question would be that you can't leave it at all because it's not less than the maximum permissable drop. To be able to leave it, it would have to be less than 2mbar.

 

[lame plumber]

4mb ?

 

[jase158]

What is an existing appliance and what is a new appliance is what I struggled with..... Worcester bosch fitted 6 months ago, can you have a permissible drop on this? what about if it is fitted 2 years ago?

 

[kirkgas]

My answer to that question would be that you can't leave it at all because it's not less than the maximum permissable drop. To be able to leave it, it would have to be less than 2mbar.

WHAT?????????
Where are you taking this info from? Haha you are just confusing what would appear to be an already confusing scenario.
REMEMBER everyone, I want to know your interpretation of the law, as in what you MUST do, I've no interest in what you do because you want to work above the law as you interpret it

 

[Keefy]

4mb ?

LOL that's what my answer would be if it were a 4mbar drop then. Long day...

 

[lame plumber]

if its been there a week and you turn up its existing if you bolt it on its new and if you have not put anything on the pipework yet its pipework, not rocket science after all the rules are there for simple folk like us to use

 

[kirkgas]

I got taught that you must isolate as there is NO permissible drop on pipe work. How do you know whether it is on pipework or appliance unless you isolate the appliances?

Have a read at the TT document if you have it,
For those that have access to it its on the bottom of p18, if I remember tomorrow I will quote the paragraphs I'm on about to see what we think then

 

[jase158]

Have a read at the TT document if you have it,
For those that have access to it its on the bottom of p18, if I remember tomorrow I will quote the paragraphs I'm on about to see what we think then

I haven't got it, but seem to remember it saying something like, to do a tightness test you must do the whole installation, then test the pipework only. under the procedure for tightness testing? might be wrong

 

[kirkgas]

What is an existing appliance and what is a new appliance is what I struggled with..... Worcester bosch fitted 6 months ago, can you have a permissible drop on this? what about if it is fitted 2 years ago?

This is easy, if its not yet commissioned its new, once its commissioned and I revisit its existing
Taking this to extremes if you fit a boiler today you can't have a leak, if I visit tomorrow and test I can have 4/8 leak as its existing, BUT although it can be left I would argue against leaving this one as the spirit of the reg is to allow for microscopic leaks which appear due to we're and tear and loss of grease etc in the fittings, where on a new boiler do you even have grease now, so if a leak has appeared since yesterday its dodgy leaving it,

 

[kirkgas]

I haven't got it, but seem to remember it saying something like, to do a tightness test you must do the whole installation, then test the pipework only. under the procedure for tightness testing? might be wrong

No might about it haha

 

[lame plumber]

better then going to prison for 5 years for manslaughter though!!

if you read the whole of my comments you see a different picture though dont you

 

[leethegasman]

You are not allowed any drop on pipework all appliances have service valves or should have.

 

[lame plumber]

You are not allowed any drop on pipework all appliances have service valves or should have.

the first bit has been pointed out, re service valves freestanding gas cookers?

 

[Keefy]

I've always understood it that if it's within the maximum acceptable drop with existing pipework and fittings you can leave it because the leak is so minute it would never reach it's explosive gas to air ratio due to other factors like ordinary room air changes. That's not to say I'd be comfortable leaving say, a 3 or 3 and a half mbar drop though, even though the law would allow me to.

 

[leethegasman]

the first bit has been pointed out, re service valves freestanding gas cookers?

Disconnect it from bayonet

 

[kel4783]

the question is would u leave a E6 meter with 8mb drop ???

 

[leethegasman]

I've always understood it that if it's within the maximum acceptable drop with existing pipework and fittings you can leave it because the leak is so minute it would never reach it's explosive gas to air ratio due to other factors like ordinary room air changes. That's not to say I'd be comfortable leaving say, a 3 or 3 and a half mbar drop though, even though the law would allow me to.

I have met a few installers that think this but you are not allowed any drop on any pipework new or old.