Tightness testing on gas installations

[Sdc111]

Hello. First of all I’m new to this site. I’m in the process of doing my apprenticeship, but now with the current circumstances we are not working. I have a couple of basic questions which no doubt will raise eyebrows, but every body starts somewhere.

In tightness testing. Regarding permissible drops. It outlines new installations and existing installations.... so what would an installation be if it was a partial upgrade. So half existing/half new

in let by. We are testing to see if the ECV is letting by and rising on the gauge. But if there’s an ever so slight constant drop. That would suggest a leak. So what do you do then, if say the tightness test was satisfactory, 1mbar drop over 2 minutes on an E6?

Apologies for the silly questions. But I keep getting told conflicting information and the book doesn’t actually cover everything

thanks

 

[Donametchi]

Hello. First of all I’m new to this site. I’m in the process of doing my apprenticeship, but now with the current circumstances we are not working. I have a couple of basic questions which no doubt will raise eyebrows, but every body starts somewhere.

In tightness testing. Regarding permissible drops. It outlines new installations and existing installations.. so what would an installation be if it was a partial upgrade. So half existing/half new

in let by. We are testing to see if the ECV is letting by and rising on the gauge. But if there’s an ever so slight constant drop. That would suggest a leak. So what do you do then, if say the tightness test was satisfactory, 1mbar drop over 2 minutes on an E6?

Apologies for the silly questions. But I keep getting told conflicting information and the book doesn’t actually cover everything

thanks

Firstly you Should be isolating the appliances.and looking at any compression joints with a leak detector fluid.

 

[ShaunCorbs]

If it’s under the permissible drop and no smell of gas then you do nothing you could note it down for reference

 

[Jones82]

Isolate all appliances, retest. 0 Drop on pipework.

If I was still getting a drop I'd be looking to my test connections and using a gas sniffer

You may get slight ups and downs due to atmospheric pressure and residual heat in pipe work. Especially if its been recently soldered.

If I still couldn't find it and there was no smell of gas and my gas sniffer was happy then I would be happy to leave a 1mb drop.

The overall approach is cover all the bases, have you checked everything, do as much as possible to be sure it is just a pressure differential and not a leak.

1mb is very very little in the scheme of pressure

 

[Donametchi]

If it’s under the permissible drop and no smell of gas then you do nothing you could note it down for reference

As I said previously.You should isolate the appliances first and test.I generally as a rule don,t walk away with any permissible drop.Did you previously state it was a new installation?
The peace at sleeping at night is always a priority for me.
you should be carrying out the proper isolate and test which in my experience can take some time.Tip for the future would be to Always test the gas before you carryout any gas works.This Keeps you right.Either way it,s all chargeable to your client.
Which you have to explain to them.
It,s all too easy to jump in and carryout your gas works without doing a tightness test which I,m guilty of in the past.Only to find the existing pipe work was leaking.But it is within the tolerance and as long as the client doe,s not swell gas,It,s your call mate.
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Isolate all appliances, retest. 0 Drop on pipework.

If I was still getting a drop I'd be looking to my test connections and using a gas sniffer

You may get slight ups and downs due to atmospheric pressure and residual heat in pipe work. Especially if its been recently soldered.

If I still couldn't find it and there was no smell of gas and my gas sniffer was happy then I would be happy to leave a 1mb drop.

The overall approach is cover all the bases, have you checked everything, do as much as possible to be sure it is just a pressure differential and not a leak.

1mb is very very little in the scheme of pressure

I,m of the same opinion as Mr Jones
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As I said previously.You should isolate the appliances first and test.I generally as a rule don,t walk away with any permissible drop.Did you previously state it was a new installation?
The peace at sleeping at night is always a priority for me.
you should be carrying out the proper isolate and test which in my experience can take some time.Tip for the future would be to Always test the gas before you carryout any gas works.This Keeps you right.Either way it,s all chargeable to your client.
Which you have to explain to them.
It,s all too easy to jump in and carryout your gas works without doing a tightness test which I,m guilty of in the past.Only to find the existing pipe work was leaking.But it is within the tolerance and as long as the client doe,s not swell gas,It,s your call mate.
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I,m of the same opinion as Mr Jones

Totally Mr Jones.But I can only assume this is a theory exercise which he,s carrying out as he previously stated he is only an apprentice

 

[Sdc111]

Hello all. Thanks for the replies. No, this was with an engineer I am working with odd days for a bit of experience. It was an e6 Meter with 1mbar drop over 2 minutes

my question is. Does it come under a new or existing installation. As majority of the gas pipe was upgraded to 22mm. And a new long run to accommodate a new gas fire (which was currently capped off)

I noticed he used the FGA to do tightness test. If it was a water u-gauge you might not even notice the drop was so small. But something constantly dropping doesn’t seem right. We used a full can of leak detector on ever joint and the meter and nothing. There was no isolation valve on the boiler, new fire had a cap end and a bayonet cooker hose. So all appliances couldn’t be isolated.

just interested to know all of your thoughts?

Thank you

 

[WC1]

What book are you looking at?

 

[Sdc111]

What book are you looking at?

essential gas safety - eighth edition.

I want to know if an 80% gas pipe upgrade comes under a “new” or “existing” installation. The corgi book does state this. To me you could argue it could be either

 

[ShaunCorbs]

I would class it as an new install but with appliances connected

Cookers are notorious for small drops

 

[Last Plumber]

You would need to test this on pipework only as others have said.

There should be no drop on domestic pipework only whether existing or not.

If there is no isolation on the Boiler then one should be installed. It should have one and you need one to continue the test correctly.

If you have a drop, you cannot correctly assess whether the ECV is passing unless you disconnect and use a cap and test point directly on the valve itself. You also cannot be certain how big the drop is until you have proved the ECV is good.

 

[Sdc111]

I would class it as an new install but with appliances connected

Cookers are notorious for small drops

thanks for your response
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You would need to test this on pipework only as others have said.

There should be no drop on domestic pipework only whether existing or not.

If there is no isolation on the Boiler then one should be installed. It should have one and you need one to continue the test correctly.

If you have a drop, you cannot correctly assess whether the ECV is passing unless you disconnect and use a cap and test point directly on the valve itself. You also cannot be certain how big the drop is until you have proved the ECV is good.

so if you was to tightness test a job you haven’t worked on. During the let by test there is a drop. You then test for tightness on an e6 and it drops 1mbar over 2 minutes and pipework not all accessible and appliances not all with iso valves. Would you deem it unsafe
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Appreciate the feedback. We used a full can of leak detector on all the new joints (probably about 15 in total) over and over again. And nothing. Not even a slight bubble. The engineer was happy that it was in the safe limit. But for some reason he was checking.

Would you guys walk away from that or not?

also is it possible rocol leak detector wouldn’t pick it up? is there a good gas sniffer on the market that’s reasonably priced and more reliable than ldf. Thanks

 

[WC1]

essential gas safety - eighth edition.

I want to know if an 80% gas pipe upgrade comes under a “new” or “existing” installation. The corgi book does state this. To me you could argue it could be either

Fwiw, of the textbooks I looked at when I did my gas (recently) the best I found was the corgi book (which you have).

 

[Sdc111]

Fwiw, of the textbooks I looked at when I did my gas (recently) the best I found was the corgi book (which you have).

cheers. Yeah I agree. Not come across anything better

 

[ShaunCorbs]

thanks for your response
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so if you was to tightness test a job you haven’t worked on. During the let by test there is a drop. You then test for tightness on an e6 and it drops 1mbar over 2 minutes and pipework not all accessible and appliances not all with iso valves. Would you deem it unsafe
[automerge]1587307300[/automerge]
Appreciate the feedback. We used a full can of leak detector on all the new joints (probably about 15 in total) over and over again. And nothing. Not even a slight bubble. The engineer was happy that it was in the safe limit. But for some reason he was checking.

Would you guys walk away from that or not?

also is it possible rocol leak detector wouldn’t pick it up? is there a good gas sniffer on the market that’s reasonably priced and more reliable than ldf. Thanks

Aslong as there’s no smell of gas / report of smell then it’s fine some of the new digi meters have an allowable limit of around 4-6 mbar depending on brand

External pipe work or internal ?

 

[Last Plumber]

so if you was to tightness test a job you haven’t worked on. During the let by test there is a drop. You then test for tightness on an e6 and it drops 1mbar over 2 minutes and pipework not all accessible and appliances not all with iso valves. Would you deem it unsafe
Post automatically merged: Yesterday at 3:41 PM
Appreciate the feedback. We used a full can of leak detector on all the new joints (probably about 15 in total) over and over again. And nothing. Not even a slight bubble. The engineer was happy that it was in the safe limit. But for some reason he was checking.

Would you guys walk away from that or not?

also is it possible rocol leak detector wouldn’t pick it up? is there a good gas sniffer on the market that’s reasonably priced and more reliable than ldf. Thanks

I wouldn't deem it unsafe going off that information.

I would find out how much is leaking and where from in this situation (you have made alterations).

Cutting the boiler off temporarily and testing pipework only would take less time than squirting LDF everywhere and once you have done that you will be a lot clearer on what is leaking. Then you can decide whether it is safe to leave it.

You have to put things in perspective. If this was an existing installation with appliances connected and no smell of gas on a domestic property with an E6, then I would be happy to forget it. I would still need to let by test the ECV.
If there is gas passing through that and leaking out elsewhere, you cannot carry out testing accurately.

ROCOL, is good LDF in my opinion. It will find most things where joints are concerned but it can depend on the position and size of the leak, whether you see it or not.

Sniffers are available from ten's of pounds to thousands of pounds depending on your needs.
They are well worth having.

The Engineer you are working with may well have made his/her mind up going off a vast amount of knowledge and experience for all we know. It may look like they had doubts but I wouldn't think they would leave it if there was any danger to be fair. Have you discussed this in detail with them? If you ask why they arrived at the decision they did, you may be surprised at their thought process. It might make perfect sense.

 

[Sdc111]

Aslong as there’s no smell of gas / report of smell then it’s fine some of the new digi meters have an allowable limit of around 4-6 mbar depending on brand

External pipe work or internal ?

A mix of internal and external. But mainly long runs and not many fittings. Think he was using a Kane. It was well within tolerance but we was still checking the joints With ldf so had me wondering why. I have only worked with water u gauges before

cheers
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I wouldn't deem it unsafe going off that information.

I would find out how much is leaking and where from in this situation (you have made alterations).

Cutting the boiler off temporarily and testing pipework only would take less time than squirting LDF everywhere and once you have done that you will be a lot clearer on what is leaking. Then you can decide whether it is safe to leave it.

You have to put things in perspective. If this was an existing installation with appliances connected and no smell of gas on a domestic property with an E6, then I would be happy to forget it. I would still need to let by test the ECV.
If there is gas passing through that and leaking out elsewhere, you cannot carry out testing accurately.

ROCOL, is good LDF in my opinion. It will find most things where joints are concerned but it can depend on the position and size of the leak, whether you see it or not.

Sniffers are available from ten's of pounds to thousands of pounds depending on your needs.
They are well worth having.

The Engineer you are working with may well have made his/her mind up going off a vast amount of knowledge and experience for all we know. It may look like they had doubts but I wouldn't think they would leave it if there was any danger to be fair. Have you discussed this in detail with them? If you ask why they arrived at the decision they did, you may be surprised at their thought process. It might make perfect sense.

Thanks for your response. Forums like this can really help people like myself out. Thing is I have trained with many different engineers, with completely different ways. The guy who I’m with now is just helping me out for the time being as college is closed and the company I’m doing my time with have closed for the time being. But He’s probably not the kind of guy who wants to be questioned too much. I guess you can imagine time is money for him. I’m still getting experience and helping out aswell.

but thanks for the replies
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I wouldn't deem it unsafe going off that information.

I would find out how much is leaking and where from in this situation (you have made alterations).

Cutting the boiler off temporarily and testing pipework only would take less time than squirting LDF everywhere and once you have done that you will be a lot clearer on what is leaking. Then you can decide whether it is safe to leave it.

You have to put things in perspective. If this was an existing installation with appliances connected and no smell of gas on a domestic property with an E6, then I would be happy to forget it. I would still need to let by test the ECV.
If there is gas passing through that and leaking out elsewhere, you cannot carry out testing accurately.

ROCOL, is good LDF in my opinion. It will find most things where joints are concerned but it can depend on the position and size of the leak, whether you see it or not.

Sniffers are available from ten's of pounds to thousands of pounds depending on your needs.
They are well worth having.

The Engineer you are working with may well have made his/her mind up going off a vast amount of knowledge and experience for all we know. It may look like they had doubts but I wouldn't think they would leave it if there was any danger to be fair. Have you discussed this in detail with them? If you ask why they arrived at the decision they did, you may be surprised at their thought process. It might make perfect sense.

So maybe stick a lever ball valve on gas feed to boiler. For the sake of testing everywhere ?

 

[Last Plumber]

A mix of internal and external. But mainly long runs and not many fittings. Think he was using a Kane. It was well within tolerance but we was still checking the joints With ldf so had me wondering why. I have only worked with water u gauges before

cheers
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Thanks for your response. Forums like this can really help people like myself out. Thing is I have trained with many different engineers, with completely different ways. The guy who I’m with now is just helping me out for the time being as college is closed and the company I’m doing my time with have closed for the time being. But He’s probably not the kind of guy who wants to be questioned too much. I guess you can imagine time is money for him. I’m still getting experience and helping out aswell.

but thanks for the replies
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So maybe stick a lever ball valve on gas feed to boiler. For the sake of testing everywhere ?

I would discuss it with the owner or responsible person first as always but that would be the way forward for me.

 

[ShaunCorbs]

It could easily rise and drop .50 mbar due to heat / cooling eg if he started the test when the sun was out then the clouds came etc

 

[GrahamM]

Hello. First of all I’m new to this site. I’m in the process of doing my apprenticeship, but now with the current circumstances we are not working. I have a couple of basic questions which no doubt will raise eyebrows, but every body starts somewhere.

In tightness testing. Regarding permissible drops. It outlines new installations and existing installations.. so what would an installation be if it was a partial upgrade. So half existing/half new

in let by. We are testing to see if the ECV is letting by and rising on the gauge. But if there’s an ever so slight constant drop. That would suggest a leak. So what do you do then, if say the tightness test was satisfactory, 1mbar drop over 2 minutes on an E6?

Apologies for the silly questions. But I keep getting told conflicting information and the book doesn’t actually cover everything

thanks

The key point here is it was an existing installation that has been altered so is not new.

What should have been done is a tightness test carried out before alteration with appliances connected and pressure drop noted. For example 1mb- no smell of gas.

After alterations as long as drop is no different than 1mb and no smell of gas all is ok. You are within permissible drop!

As soon as you isolate any appliances and have a drop you MUST then trace and repair as you are not permitted to walk away from a drop on the carcass!

Another point to be aware of is your employer specific guidelines. Some employers do not permit any pressure drop at all!

 

[Sdc111]

Thanks everyone for the feedback. Great to hear other opinions.

Today we installed a new gas pipe, where eon had capped the meter off for a 3mbar leak on another e6. Not sure why or if gas was smelt. He renewed the gas pipe, only a 3 meter run, feeding one hob.

tightness test showed a 0.15mbar drop on tightness testing. It’s the first time I have seen digital being used. it’s always been a u-gauge before where you would not see that movement. He signed it off and said that was ok.

Guess with things close to the mark it’s a game of opinions?

 

[Scott_D]

As said above
Always test before starting any work so you know what you are dealing with.

 

[Funky dog]

Hello. First of all I’m new to this site. I’m in the process of doing my apprenticeship, but now with the current circumstances we are not working. I have a couple of basic questions which no doubt will raise eyebrows, but every body starts somewhere.

In tightness testing. Regarding permissible drops. It outlines new installations and existing installations.. so what would an installation be if it was a partial upgrade. So half existing/half new

in let by. We are testing to see if the ECV is letting by and rising on the gauge. But if there’s an ever so slight constant drop. That would suggest a leak. So what do you do then, if say the tightness test was satisfactory, 1mbar drop over 2 minutes on an E6?

Apologies for the silly questions. But I keep getting told conflicting information and the book doesn’t actually cover everything

thanks

If you have upgraded a installation treat it as a new no drop

if it’s not letting by go on to stabilisation and tightness test and see how much it’s dropping by then resolve the leak.

 

[GrahamM]

Thanks everyone for the feedback. Great to hear other opinions.

Today we installed a new gas pipe, where eon had capped the meter off for a 3mbar leak on another e6. Not sure why or if gas was smelt. He renewed the gas pipe, only a 3 meter run, feeding one hob.

tightness test showed a 0.15mbar drop on tightness testing. It’s the first time I have seen digital being used. it’s always been a u-gauge before where you would not see that movement. He signed it off and said that was ok.

Guess with things close to the mark it’s a game of opinions?

Perceptible movement is 0.2mb on a digital gauge so your 0.15 drop is within these limits so not an issue.
Dont like using digital gauges anyway. Especially on a windy day as bounces around too much!
Cant beat the Regin Premier when got a full day of CP12's.

 

[sammathias]

Haven't read everyone's replies but I'll stick my 2p in anyway. New installation you shouldn't have any drop on pipework. If I was to be doing a service for instance on an existing installation and I've got a 2mb drop on say an e6 meter before and after service then it's simply noted on the cp12...unless there's a smell of gas.... The second you start isolating appliances looking for an acceptable drop means you will have to find the source of the drop...not always easy. There's tolerable drops on the different types of meters for a reason.
I've had a letby test rise by 0.6mb so thought the ecv was letting by so ldf the ball itself and it was fine. Turnt out to be heat transfer from the sun onto the external pipe run.
Another good senario.....you are replacing a combi....only appliance on existing gas supply. Tightness before work starts and you have 2mb drop. So you change boiler and you still have 2mb drop.....clearly thats indication there is a 2mb leak on pipework that needs looking at, a few I debated this with seemed to think because the pipework installation is existing and there was no smell of gas it's fine and just noted....that would be the case if say they had a gas hob and fire on the install.