1.5 mbar drop

[Backboiler]

Hi all
I've been to an existing installation with two gas appliances; a combi and a gas fire. I found a permissable 1.5mbar drop when tightness testing but out of curiosty saw fit to investigate the leak. I isolated the gas tap underneath the boiler, tested again and no leak. I re-opened the said tap and used LDF from the tap to the inlet on the valve. I couldn't see any evidence of a leak so used my super-sensitive sniffer. I tested the pipework and around all screws holding the gas valve together but I still couldn't locate the leak. Is my asumption correct in thinking that the gas valve seals are passing and through into the flue?

 

[andyg0507]

have you tested the gas valve to see if its letting by??

 

[Backboiler]

I dont know if it will have a test nipple on the outlet side with it being a modulating zero rated gas valve? Has it?

 

[kirkgas]

if you have determined the gas is not leaking OUT of the valve it must be leaking THROUGH it as you say, can you put your super sensitive sniffer in the flue, if not accessible then can you open the combustion chamber and get the snifer in there with the gas supply on, either way it has to be a faulty valve, so is ID and capped until rectified because it is on a safety device NOT because there is a 1.5mb drop on the appliance), again this will open the debate on whether you should/could/needed to check this, yes it is safer but you have now capped an appliance (i hope), left them with no heating and they now need to pay for agas valve

 

[wnjswozo]

opening a bag of worms here,theres a reason your allowed a drop on tightness test with existing applainces because over a period of time the gas will pass on certain controls,due to wear and tear,once its outside permissable drop then time for action ,provided no smell

 

[GQuigley67]

so if the valve passes then doesn't that mean the FSD won't work ?

 

[Plucky]

Correct

 

[Backboiler]

Correction. The safety device operated correctly

 

[mickeyuk]

test the fire

 

[Backboiler]

The fire is sound. There is only a drop on the system when I open the isolation tap to the boiler. read the 1st post

 

[andyg0507]

have you determined that the gas valve is definitly not leting by then?? if there is no drop on gas fire and the boiler is at fault, it must be a faulty gas valve, have you used the sniffer in flue etcc...?

 

[mickeyuk]

If the gas leak is on the boiler whats the problem .Its ok you are allowed a drop. regulations can lead to ocd ! ha

 

[GQuigley67]

as long as the FSD works then should be fine, I think ..

 

[GrahamM]

If the gas leak is on the boiler whats the problem .Its ok you are allowed a drop. regulations can lead to ocd ! ha

As discussed in full on another thread. You are allowed a permissible drop on an installation with appliances attached and legally can walk away at that.
Because the OP investigated further he has identified an appliance has a gas leak. This has to be attended to now.

 

[tamz]

Agree with Graham here. Next time think before your curiosity bites your rse.

 

[GrahamM]

No he does not !!!! paranoid people! why would they give you a drop in the first place . if no drop on pipework and in the limits on appliance go home and forget. These tests were done 30 years plus ago,.As i said before paranoid just like the gas inspectors visit it was his rse that was twitching not mine.Gas saftey needs its rules and regs i wont argue with that.But its going too far and more of the fitters over the last few years who have been in the trade for years and good at the job are saying sod it!!

You are missing the point I attempted to make. Have a read at regs.
You do a tightness test. You have a 1.5 mbar drop. You have not isolated any appliances and it is standard 22mm pipe with a G4 meter. You can then walk away knowing you have complied with the regs. If you chose to do so!

The other scenario is what the OP has carried out. Finds the drop, isolates the appliances and identifies the boiler is leaking gas. As he has identified an individual appliance is leaking gas, he cannot walk away. An appliance has been identified that may constitute a danger. The gas leak must then be traced and repaired or the appliance cut and capped.

 

[Plucky]

I dont see the issue.

He has found te problem now he has to fix it.

So he replaces the gas valve and earns money for doing it.

And in return customer is safe. If you appoach a customer and say you have a leak on your gas valve in your boiler most will be keen to have it repaired/replaced

 

[kirkgas]

You are missing the point I attempted to make. Have a read at regs.
You do a tightness test. You have a 1.5 mbar drop. You have not isolated any appliances and it is standard 22mm pipe with a G4 meter. You can then walk away knowing you have complied with the regs. If you chose to do so!

The other scenario is what the OP has carried out. Finds the drop, isolates the appliances and identifies the boiler is leaking gas. As he has identified an individual appliance is leaking gas, he cannot walk away. An appliance has been identified that may constitute a danger. The gas leak must then be traced and repaired or the appliance cut and capped.

so if you cant have a leak on the pipe and you cant have a leak on the appliance WHERE are you allowed to have up to 4/8mb microscopic leak(s) on a system that i leave every day, while complying with the regs

 

[kirkgas]

I dont see the issue.

He has found te problem now he has to fix it.

So he replaces the gas valve and earns money for doing it.

And in return customer is safe. If you appoach a customer and say you have a leak on your gas valve in your boiler most will be keen to have it repaired/replaced

i agree with you where i have underlined, however it is the engineers who take it upon themselves (in the name of being safer than me) who decide to overstep the regs and isolate appliances and then say "oops sorry you have a 1mb leak on the carcass and it cant be left on" IF you discuss it first and explain the ramifications of your actions may lead to the customer having no gas for a few days and an invoice for £*** and they agree then all is well

 

[Plucky]

True Kirk,

This is always an area where it boils down to engineering judgement and personal opinion. I think we all have slightly different interpretations of regs and our duties.

 

[Backboiler]

I think that most engineers would investigate a 1.5mbar drop if it was in their own property, so why would you sign the ticket and walk away from someone else's property knowing that there is a gas leak?

 

[gas57]

you need to turn gas of on boiler isolating valve connect manomiter to gas valve inlet test nipple and turn gas back on then turn gas valve back off if fsd is leaking manomiter will drop

 

[kirkgas]

I think that most engineers would investigate a 1.5mbar drop if it was in their own property, so why would you sign the ticket and walk away from someone else's property knowing that there is a gas leak?

i would agree 100%, however by definition of it being in my own house i have allowed the owner to make an informed decision as to whether the investigation (and subsequent cost/disruption/hassle) should go ahead, what i have a problem with is people overstepping the regs WITHOUT allowing the owner to make the informed judgement, but ultimately leaving the owner with the cost, IF there is a drop and there is no smell or report of smell, what is the real risk? to me it is all about common sense, eg YOU fit a cooker and pipework today, the next day (for whatever reason) i test and because it is now existing i am allowed to leave a 4/8mb drop, i would NEVER leave this, although i can by law, as my engineering judgement is telling me that the spirit of the 4/8 allowance is for microscopic leak on the "old" system but that type of leak cannot appear overnight so there must be an issue with what you did yesterday

 

[GrahamM]

so if you cant have a leak on the pipe and you cant have a leak on the appliance WHERE are you allowed to have up to 4/8mb microscopic leak(s) on a system that i leave every day, while complying with the regs

I have re-my posts and it make sense to me, but I don't think anyone else is reading them in full.
I'll say again. Within the regs you are allowed to carry out a tightness test have a permissable drop and walk away without any further action. As soon as you start isolating appliances etc. to trace the leak it then becomes an issue. As soon as you take it upon yourself to try identify where the leak is coming from and identify it is a particular appliance or the carcase itself, you must then repair the leak. You will have highlighted the leak is coming from a particular appliance(s), the carcase, or both. You are not permitted to leave a drop on pipework alone so must trace/repair. You are not allowed to leave an appliance connected that may constitute a danger so must repair or cap.
It is when you pinpoint where the leak is coming from you MUST take action.

True Kirk,

This is always an area where it boils down to engineering judgement and personal opinion. I think we all have slightly different interpretations of regs and our duties.

In this instance the regs are quite clear in my opinion!

I think that most engineers would investigate a 1.5mbar drop if it was in their own property, so why would you sign the ticket and walk away from someone else's property knowing that there is a gas leak?

Because you are legally permitted to and may be working for a company that does not want to get involved lifting floorboards to trace a 1.5 mbar drop.

i would agree 100%, however by definition of it being in my own house i have allowed the owner to make an informed decision as to whether the investigation (and subsequent cost/disruption/hassle) should go ahead, what i have a problem with is people overstepping the regs WITHOUT allowing the owner to make the informed judgement, but ultimately leaving the owner with the cost, IF there is a drop and there is no smell or report of smell, what is the real risk? to me it is all about common sense, eg YOU fit a cooker and pipework today, the next day (for whatever reason) i test and because it is now existing i am allowed to leave a 4/8mb drop, i would NEVER leave this, although i can by law, as my engineering judgement is telling me that the spirit of the 4/8 allowance is for microscopic leak on the "old" system but that type of leak cannot appear overnight so there must be an issue with what you did yesterday

Did you carry out a tightness test before and take a note of any pre-exiting drop? If no leak when you started then you cannot walk away having created one, but if there is 1 mbar drop in existing system and you install your cooker and still have a 1 mbar drop then that is permissible.




This topic becomes more of an issue depending on your employment circumstances.
If I was working for myself and came across a permissible drop(as some mentioned above) I would discuss with the customer what action to take. Explaining, if it is narrowed down to the pipework itself it may involve lifting floorboards etc.
If you were working for a company that was leaning more towards quantity rather than quality and if you were to start poking around tracing permissible leaks, knowing you would still be expected to do your 10 annual inspections that day, then I think it will be more of a case of taking not of the permissible drop and on to the next job.

 

[kirkgas]

GrahamM i didnt want to repost all you have just written but i have read the regs many times, and dont agree with what you have said, the regs clearly say you can leave 4/8 with no smell or report of gas smell we all agree on that, we also all agree the regs say if you dont isolate appliances you can walk away, and we all agree if you get it back to carcass only you cannot leave it, where we disagree is where you are saying if i confirm the leak to be on a specific appliance i MUST fix or isolate, where in the regs does it say that? you do mention an appliance cannot be left if it constitues a danger, i agree with this but having a microscopic leak on an appliance that you cannot smell doen not constitute a danger, having read IGE/UP/1B very carefully it does not say if you confirm drop is on specific appliance it MUST be dealt with, the regs are the regs and there are always going to be scenarios that make a mockery of them, here is another, you do TT on existing install containing cooker, find drop and are allowed to leave it without checking if it is on cooker or pipe, go back next day to remove cooker, blank it and do TT which drops therefore proving yesterdays drop and todays drop were in fact on the pipe, cant leave it today as there isnt a cooker, so was yesterday any more dangerous than today? i would say not but icould leave a leak on one but not the other. the scenario i gave in my last post about someone fitting a new cooker and pipe and me finding a leak the next day was based on the first fit being 100% new install so the installer could not have any leak but next day i could leave 4/8 which i wouldnt as there was no chance of microscopic leak that had developed over yrs as the pipe and cooker were new yesterday but i could have left it if i chose to invoke the regs to the letter of the law rather than use engineering judgement and experience, i agree with you i dont think this post should be about interpretation it is clear in the regs what can and cannot be done, we just seem to have trouble understanding what we can and cannot do , and after that we have others choosing to overstep the regs by doing extra work and possibly creating a prob for the customer that wasnt discussed beforehand

 

[GrahamM]

GrahamM i didnt want to repost all you have just written but i have read the regs many times, and dont agree with what you have said, the regs clearly say you can leave 4/8 with no smell or report of gas smell we all agree on that, we also all agree the regs say if you dont isolate appliances you can walk away, and we all agree if you get it back to carcass only you cannot leave it, where we disagree is where you are saying if i confirm the leak to be on a specific appliance i MUST fix or isolate, where in the regs does it say that? you do mention an appliance

I have trimmed your post to concentrate on highlighted mater.
So what I am saying is that without pinpointing exactly where the permissible drop is coming from and no smell of gas you can walk away. Job done.
This is as per the guidelines.
But, as soon as you investigate further you have stepped outside the procedure for tightness test and fall back into the realms of GSIUR. Identify it is a leak from the appliance itself and you cannot walk away even though it is permissible as per tightness test procedure. This is as per GSIUR reg 34. (read it in full including the ACOP) You have now identified an individual gas appliance has a gas leak and cannot leave it in operation.

I personally have no problem with the clarity of this topic. Getting too involved and stepping outside the exact procedure laid down puts you within the boundaries of other regulations.

 

[kirkgas]

i think this topic has reached its conclusion for me, having read reg34 i dont see anything we havent discussed, it is there that you cannot allow an appliance that is dangerous to be used, i say an appliance with a small leak with no smell or report of smell isnt dangerous therefore doesnt fall into to where you are interpreting, i asked where it says in the regs or IGE/UP/1B that once the leak is identified as being on one appliance that then that appliance is deemed ID, there is no difference to microscopic leak(s) being on one appliance or split between 2, what would you do if you did TT found this 1.5mb drop, then split the appliances and proved there was 1mb on one and 0,5mb on the other would you then shut down both appliances? no way am i having a dig at you at all here, i just like to make sure im on the right track and always take the time to read and digest other experts opinions as it helps keep us on top of our game (then obviously i ignore every opinion thaat doesnt match mine😛) i keep going back to the fact there is nothing written anywhere saying leak on one appliance is more dangerous than on some appliances

 

[GrahamM]

Ok then kirkgas. Going by your last post.
Stepping away from the tightness test. You know an appliance has a gas leak. At what limit is it classed as not being a danger as per reg 34?
looking at an individual appliance, is a gas leak no matter how small not classed as a danger?

 

[tamz]

I have a 1mb leak on my hob but to fix it would mean getting a screwdriver and a pair of grips. Should i write myself out a warning notice incase the kitchen blows up😱
Maybe it is time they introduced mplr's on domestic. That would give you something to think about😀

 

[mickeyuk]

Reg 34 says it to you Graham or maybe you haven't read it right !I personally think you are over the top and probably will require a stomach pill as you get older,I wish everyone worked to your standard but im sure there would be health issues good luck and keep up the standards

 

[raymondo68]

Hi Tamz

Excuse my ignorance but what are mplr's?

 

[arfurdaley]

Maximum Permitted Leak Rates, used in commercial tightness testing

 

[raymondo68]

Having read this very interesting thread and referred to the documents listed I think I can see where the there is scope for interpretation. Reg 34 does state that it is up to the RGI to use their judgement as to what constitutes a danger.

So the scenario for me goes like this:

TT reveals 1.5mb drop with appliances connected and no smell of gas. RGI can issue gas safety certificate with this information recorded. The RGI has then discharged their responsibility by informing the responsible person about the situation. In the vast majority of circumstances I would guess that the RP would want this matter investigated further, although this will depend largely on what the RGI says at the time.

So, RP says yes please investigate further, RGI now explains possible implications of investigating further (cost, removal of supply or appliances etc.).

RGI carries out further investigation and identifies leak on boiler gas valve. !!JUDGEMENT TIME!!

My judgement in this case is that the boiler is ID. My reasoning is this. I don't know for how long this 1.5mb drop has been occuring and whether or not it is part of a rapidly deteriorating situation. If the gas valve is not seating correctly, next time it closes it might produce an 8mb leak, or indeed no leak at all.

I always say to RP's whether thay are tennants or home owners " I need to be able to sleep tonight and you want to wake up in the morning"

This approach is much better for my health and the health of those who have placed their trust in my skills and judgement.

I carry out LGSR's all day long. Many of the larger Landlords now do not accept any drop on their pipework or appliances. I love this approach as it removes all ambiguity.

Keep up the debate guys, I am still relatively new to the forum but I am drawn back more and more frequently owing to the excellent discussions that take place.

Regards

raymondo

 

[kirkgas]

Ok then kirkgas. Going by your last post.
Stepping away from the tightness test. You know an appliance has a gas leak. At what limit is it classed as not being a danger as per reg 34?
looking at an individual appliance, is a gas leak no matter how small not classed as a danger?

how do we know it is leaking is my first question, if from smell of gas then it is ID, if it is picked up from TT with no smell then it is within tolerances so by definition MUST be ok to leave, nowhere in the regs does it say a 4mb drop on existing MUST be spread over more than 1 appliance, if you have a cooker and fire or just a cooker what difference does it make as long as there is no smell of gas
the allowable leakage rate is to allow for "old" microscopic leaks developing over a period of time from dried up gas grease leaking etc. re your scenario it changes from being not dangerous to dangerous WHEN you can smell it ot it goes over 4/8mb drop