Purging procedure question...?

[kirkgas]

Kirkgas I am sure you are correct in your method on a new installation, I personally always do a tightness test after joining two pipes regardless of using LDF on a joint.

do you mean you do one before and one after? so you do TT then disconnect a fitting to purge then a second TT to confirm you have tightened the fitting properly? if so that is up to you but surely unnecassary? as the procedure is noted that when you disconnect gas fittings you only need to test with LDF to confirm it is gas tight, and if you only do one TT after you reconnect how would you know that any drop recorded was not caused by you

 

[gasmarc]

Yes two tests . regardless what regs say I always do a test afterwards as i like to sleep 100% sound LOL

 

[gbgas001]

The main point of a purge is to fill the gas meter with greater than 90% gas.... normally 100%, this is why its always 5 times the badge capacity. If this is done and you still have a gas / air mix in the pipework a flash back in the pipe work will extinguish when it hits the greater than 90% gas.

pipe work of normal domestic diameters has the strength to hold a flash back but volume in the meter with a 5 to 15% mix will explode, explosions in confined areas are bombs..... possibly taking out the gable end of the house.

The only time the volume has to change is on bigger pipes, in that situations above 0.02m3 by the time the gas air mix has reached the point that you are purging with your ignition source the meter MUST be full of gas.... so cant explode.

 

[kirkgas]

Yes two tests . regardless what regs say I always do a test afterwards as i like to sleep 100% sound LOL

as you say you do what you want above the regs so you KNOW you are doing things properly

 

[gasmarc]

everyday I try and learn something new ,being doing it for years now still know jack lol

 

[kirkgas]

everyday I try and learn something new ,being doing it for years now still know jack lol

just like the rest of us then,

 

[sparra1100]

Yes two tests . regardless what regs say I always do a test afterwards as i like to sleep 100% sound LOL

am the same before and after and use my sniffer to test when theres gas there when purging

 

[tamz]

Using a sniffer is not a good idea when purging. It will pick up small amounts of gas and definitely won't tell you when you have 90% gas unless you are spending around a grand for a gasco.
Do it the way it says in the book.

 

[sparra1100]

never been a problem for me, i just wait till it goes off the scale have ye seen how much gas comes out when doing 5 times the on the meter so to speak i no what it says in the book but that scares me the amount of gas into someone house and i no lots of people and not met anyone who does it that way all say the same, scary

 

[tamz]

It is not in the least scary if you think about it. Unless you were purging into a box of 0.2m3 (less than 2 ft x 2ft x 2ft) then you will never get anywhere near lfl's.

 

[fuzzy]

0.35 cubic foot aint much with a window open

 

[kirkgas]

never been a problem for me, i just wait till it goes off the scale have ye seen how much gas comes out when doing 5 times the on the meter so to speak i no what it says in the book but that scares me the amount of gas into someone house and i no lots of people and not met anyone who does it that way all say the same, scary

sorry but there is NOTHING scary about purging as per procedure, first thing is to purge to ventilated area= no build up of gas to 5-15% also you advise no smoking or electrical switches on or off, and TBH it takes what 20-30 secs to purge the correct volume via a cooker, no risk in doing the job as per procedure

 

[sparra1100]

sorry but there is NOTHING scary about purging as per procedure, first thing is to purge to ventilated area= no build up of gas to 5-15% also you advise no smoking or electrical switches on or off, and TBH it takes what 20-30 secs to purge the correct volume via a cooker, no risk in doing the job as per procedure

dont disagree with u kirkgas thats not my point done it that way by the procedure few times and thats an awful lot of gas took ages to clear,i usually purge thro the cooker first then at the boiler with my sniffer plus on some jobs you can only just get at the meter to cap it never mind purging and gas rates (that doesnt mean am not gas rating just using as a example)