purging info

[mutley racers]

Hi guys, i have just read a book today which suggests that you do not need to do any calculations on domestic systems when purging. You just purge 0.035 m3. Is this correct?

Cheers

 

[kirkgas]

Hi guys, i have just read a book today which suggests that you do not need to do any calculations on domestic systems when purging. You just purge 0.035 m3. Is this correct?

i have read a gas book many times that doesnt suggest this, is states it as a legal requirment, ( depending on meter type and pipe size) why are you reading such a book?

 

[mutley racers]

Hi kirkgas, i am reading this in the Gas installation technology 2nd edition by R.D. Treloar.

I am reading it as i am studying my NVQ3 and will eventually be taking my CCN1.

I quote 'to successfully purge a gas installation first you need to determine the purge volume. For the smaller more traditional domestic gas installations utilising pipework upto 28mm and incorporating a domestic sized gas meter, no calculation is undertaken and if a G4 or E6 electronic metric meter was installed the purge volume would simply be 0.01 m3. Where the older imperial U6 gas meter is installed this volume would be 0.35 m3. However, where the system employs an extensive amount of pipework and/or pipework greater than 28 mm with possibly a G10/U16 gas meter, the purge volume would need to be calculated; if the total purge volume is found to be over 0.02 m3 then the gas should not be permitted to discharge freely into the room'.

 

[prs1]

You got an old book and what kirk is telling u is correct always calculate your purge vols. theres also a crucial amount now if below u can purge to air if over u have to purge to flame.Try and get ur self an upto date book.

You will be expected to keep up with the changes when u have your acs

 

[Kip]

Purge till you smell gas. works a treat for me. LOL

 

[prs1]

Kip both feet planted firmly in the real world! Totally agree with you pal but the conversation started off about books saying " " and he has got to do his acs didnt want him 2 get turfed out off practical!

 

[justlead1]

Always open the window first, it give more room for error with the maths.

 

[mutley racers]

Hi guys, the book am using was just published this year.

is this wrong then?

 

[Kip]

Its been 8 months since i did the ACS so now forgotten the purge but i as far as i can remember when learning it all is that with a metric meter it's 0.1m3 and with a imperial its 0.35ft3.

BUT

I vaguely remember this being changed late last year because alot of house gas pipes are of greater volume and its now to be worked out, ill take a peak in the books on monday. theyre all in the van and im sat with a chilled beer

 

[kirkgas]

Its been 8 months since i did the ACS so now forgotten the purge but i as far as i can remember when learning it all is that with a metric meter it's 0.1m3 and with a imperial its 0.35ft3.

BUT

I vaguely remember this being changed late last year because alot of house gas pipes are of greater volume and its now to be worked out, ill take a peak in the books on monday. theyre all in the van and im sat with a chilled beer

kip its a bit scary that after ONLY 8 months you have forgotten how to purge, what kind of work do you do on a daily basis (perhaps i'm being harsh if say you only ever repair or service and have never installed any appliances or fitted any new pipe in the last 8 months) PS E6 meter purge is 0.01m3, U6 imperial as you say 0.35ft3, up to 28mm pipe

 

[newbie1]

its amazing purging is determined as well by the installation volume i know its a lot to remember but guessing purging isnt really on..the figures quoted are correct for most domestic situation but you cant allways assume thats going to be good enough
to generalise
iv less than 0.02 cubic mtrs then purge to air
iv above 0.02 cubic mtrs then purge and ignite
having said this its easiest to use the cooker and purge and ignite to be on safe side

 

[Bernie2]

Hmm!

Interesting!

I wonder, if we are truthful, how many fitters/engineers really do things by the book and not the quick way.

Purging seems to highlight the problem. Many people just seem to purge until they get gas coming out, they don't look at the meter reading, unless of course a problem occurs.

Its the same with many other things I suppose.

The thing is do we need too, if safety is not compromised and the appliances are working okay?

 

[newbie1]

if not purged correctly and to correct amount flame could go out and gas would still be escaping then reignite...ie kaboom

 

[prs1]

As newbie says u could be leaving a property with a potentialy AR situation.
Would those same people not bother to do there visual risk assesments and check safteys on all other gas appliances in house.
Personally ive always made an effort to do it by the book,when people start to deceide for them selves which parts of the REGS and proceedures they dont need,where does it stop, u cant deceide which bit apply to u
Id rather have piece of mind