Just had an argument about tightness testing

[GQuigley67]

yes it is imprortant to know that the drop is only allowed with appliances included in TT, if you isolate appliances and test carcass and there is a drop that is a big NO NO

 

[CMairiD]

'Sok Tamz, you explained it perfectly and I'm just home from the pub! *hic*

 

[Dotty]

i am of course teasing,no offence meant just have a GSOH

No. Really. I think he has!

 

[Pssst]

Sound like the sort of tossers I used to see in Plumb Centers all the time before I stopped using em; Snickers work trousers (Regulation bright blue), Walk straight round counter like they own the place and get their gear from the back themselves, rest beer gut on counter while drinking free coffee and telling everyone that will listen that "They're pulled out with work, aint had a day off since 1976, fitted 2 full systems since 8 this morning and still got another 3 to fit before 4 o clock & I don't need to do a tightness test cos I'm the bestest fastest gas fitter in (Insert the town/city of your choice)!" I always do a test before and after every job cos to be honest, I'm just too pretty to go to prison😎
These sort of blokes can make you doubt yourself and love to think they look big in the merchants. Rant over!!😡

Hahahahaha..that description is so true...as is the OPs methodology.

Always test before doing anything.

That way,you know where your starting from and most importantly,you can indicate to the customer that there are issues before starting,thus keeping yourself in the clear,giving the punter confidence in your work and maybe picking up some extra business in finding and fixing the problem.

 

[metaldust9]

every landlord cert ive seen says TT test yes/no ,so if its not needed whys it on there,i would always do one ,cos youre the last in there and owt gones wrong your to blame full stop they.ll come after you doesnt matter to me weather its a l mb drop or a four mb drop i still dont feel comforable with any drop as it will only get worse over time ,so i always cover myself

 

[mylesy]

the permisable drop is only allowed on existing appliances, if you isolate all the appliances and test the pipework only then there is no drop allowed at all. even if there is on an existing appliance with no smell of gas id find out which applience it is an investigate it. at the end of the day its down to you with this rule. i dont like having a drop at all. test at beggining to make sure its not you that has disturbed the pipework. always good to excercise caution.

 

[Babylunch]

I am a ng engineer and if I talked to those too knob heads at a job and they gave me those answer's, riddor and hse would be my next conversation, and to the guy who posted this, your spot on with your testing limits. , But you are allowed a pd drop depending on mtr size and pipework size and installation. As long as there is no smell,

 

[jase158]

Second post in as many days.
Just been in plumb centre and was earwigging on two guys talking about testing.
Now I'm a commercial fitter with domestic as well. Granted I have not used my domestic that much over the years but it does get used.

Now the way I was taught was the following;

Upon entering a building to do gas work you do the following:
1 minute let-by at 10mbar
1 minute stabilisation at 20mbar keeping at 20 for that minute
2 minutes at 20mbar.
Anything above 75mbar is medium pressure and requires a different test (this was where I got into conversation with them as they said anything over 82.5 was medium)

Any Drops at stabilisation are fine, any drops within 2 minute test need to be within permitted limit otherwise test fail and you need to find the source

You then do any work IE boiler service, then after the work do the same again.

Now these two guys argued with me for five minutes that you do only need to do a 2 minute test at 20mbar.
Any drop is fine as long as there is no smell of gas.
Also that doing a test upon entry is not needed, and I was wasting my time.

Now somebody please tell me I'm right, I don't have my domestic viper with Me so cannot check, but I will be mortified if I have been doing it wrong all these years!

Honestly these lads have put complete doubt in my mind now, to the point that I'm worried about doing a test today!

Now I am not gas safe registered yet, but isnt it obvious, if there is a drop, there is a leak, which means that there is gas leaking into a house, which means that the installation is dangerous, I also got told by college that the first test must be done as if it is leaking then you must cut the gas off and declare it as unsafe, if the customer does not let you fix it, then you must report it to the gas board, I believe.

And common sense is that if you don't do the test first, then when you work on it, you may cause the already leaking pipe to get worse and of course, the customer will always blame you.
"it was working before you came"

 

[AWheating]

Now I am not gas safe registered yet, but isnt it obvious, if there is a drop, there is a leak, which means that there is gas leaking into a house, which means that the installation is dangerous, I also got told by college that the first test must be done as if it is leaking then you must cut the gas off and declare it as unsafe, if the customer does not let you fix it, then you must report it to the gas board, I believe.

And common sense is that if you don't do the test first, then when you work on it, you may cause the already leaking pipe to get worse and of course, the customer will always blame you.
"it was working before you came"

you are allowed a small drop if appliances are connected as stated by others in the post.

you can only "cut the gas off" with permission, if you can not gain permission you then need to inform the gas board. They will then come along and do whatever is needed to make safe, this can include digging up road and cutting gas supply.

 

[Pssst]

As many will know, its quite possible to have no perceptible drop but still have a smellable leak.

Equally, in the right circ you could have a drop or a rise which isnt attributable to leakage/let by.

 

[kirkgas]

As many will know, its quite possible to have no perceptible drop but still have a smellable leak.

Equally, in the right circ you could have a drop or a rise which isnt attributable to leakage/let by.

where can you have a leak that is large enough to smell but doesnt show as a drop on a u gauge? unless you mean on the upstream side of the ECV

 

[mylesy]

You can have fluctuations with the pipework temperature, but in rare circumstances you could have let by from the ecv and a leak at the same rate, so it shows no drop but there is a leak, in two places. You would be unlucky to get that. But if in doubt, unscrew the governor and spray leak detector into the closed ecv.

 

[radswilldo]

I would say that I have to contact southern gas to either change the ecv(let by) or governor(working pressure let by) on 1 in every 6 safety checks I do. I do not understand chaps that don't do let by/tightness tests when cariing out safety checks/servicing!

 

[billybob150811]

havent read all the post but your bang on in my book ryster i do a let by and tightness before starting work so if there is a problem you let them know before you start dont know if its manditory but i do better safe than sorry

 

[tamz]

Devils Advocate.

Who is to say, after you do your let by test then open and close the valve to increase the pressure for your test, that the valve is still holding 100%?

All that is between you and a leaking ECV is perhaps a bit dried out grease!

 

[kirkgas]

You can have fluctuations with the pipework temperature, but in rare circumstances you could have let by from the ecv and a leak at the same rate, so it shows no drop but there is a leak, in two places. You would be unlucky to get that. But if in doubt, unscrew the governor and spray leak detector into the closed ecv.

if you have a leak rate at the same rate as the ecv lets by this is why you do let by at 10mb and TT at 20mb, so that the leak will show on the TT, as it is being done at a different pressure

 

[mylesy]

Take it you not has it before then, trust me it happens. Found the leak to be on a boiler, isolated it then retested, at 10 mbar at first as you rightly say you should, and I had let by. Which didn't show at first. Had transco fit a new ecv, I fixed the boiler. All good after that. That's why I'm saying it's not always so obvious, even with the guide lines and and so on. You have to be confident and know what your doing.

 

[gazzathebassman]

generally a tightness test is carried out , if it is a new supply,or the supply has been turned off, if you are going to work on the actual installation or add appliances, or the customer suspects a gas leak (smell of gas). You dont have to do a tightness test if you are servicing an appliance ,unless your company wants you to do one, as you can isolate at the isolating valve test disturbed joints with LDF. Contrary to a previous reply, a tightness test includes a let by test for 1 minute at 7-10mb, a temperature stabilisation for 1 minute at 20-21mb, and a tightness for 2 minutes at 20-21mb / this is for a low pressure installation. Its never been acceptable for a stabilisation test to be done with the let by test (thats for bartdude pubmember attention)

 

[Alex Knight]

generally a tightness test is carried out , if it is a new supply,or the supply has been turned off, if you are going to work on the actual installation or add appliances, or the customer suspects a gas leak (smell of gas). You dont have to do a tightness test if you are servicing an appliance ,unless your company wants you to do one, as you can isolate at the isolating valve test disturbed joints with LDF. Contrary to a previous reply, a tightness test includes a let by test for 1 minute at 7-10mb, a temperature stabilisation for 1 minute at 20-21mb, and a tightness for 2 minutes at 20-21mb / this is for a low pressure installation. Its never been acceptable for a stabilisation test to be done with the let by test (thats for bartdude pubmember attention)

Threads 4 years old hope they'd have worked it out by now

 

[Ray Stafford]

Threads 4 years old hope they'd have worked it out by now

Or gone KABOOM!