Gas pipe size

[Adrian80]

Dear all,

I had a search on the forum and couldnt quite find what i was looking for.

Basically having a new installation done and the corgi man said i would need a 28mm gas pipe, however, the original was only 15. i was going to upgrade to 22mm which i have a load left over from the CH but dont really want to splash out on a load of 28

Does any of you know how to calculate the exact requirements for the piping.

basically the arrangement will be meter tee to boiler carry on then another t, one going to the cooker and then one to the fire,

I guess you need to know the energy output of each appliance, and the length of the run, number of elbows in the installation, and the maximum capacity of the meter. But i have had a look on line for a calculator but cant find one.

the boiler is 30 kw, the fire is 2.3kw heat input and the cooker dont know but the mrs wants a 6 burner range job..

the length of the total run is about 10-15 meters.

thanks in advance
adrian

 

[corgiman]

Dont you trust your CORGI man, if not get someone else in and leave the poor chap alone

 

[Adrian80]

Its just the discrepancy between the two installations also the boiler only has a 15mm gas feed pipe.

so i would have thought the rate limiting step is the 15mm entering the boiler,

I just like to educate my self...

 

[Adrian80]

also i dont think my corgi man and corgiman are the same person...
sorry for the confusion

 

[landyandy]

Hi.
I would disregard that the boiler has a 15mm feed and that you have some 22mm left over.
If your corgi man has sized the pipe for you and it needs 28mm, then thats what should be used.

Unless he has got his calcs. wrong.

Andy.

 

[Adrian80]

i know your corgis are quite experienced and sometimes just know what size to do, but he didnt get the pen and paper out or a wheel thing, so no calcs, but then again he might be the rain man and do them in his head...

I was just wondering if it was border line and if 22 would be sufficient, but i get the feeling 28 is the preference and its just a better safe than sorry thing?

The problem is am skint, if i have to do 28 i got to do 28, but if i can get away with 22, its gonna save me some cash which i desperately need.


Adrian

 

[gremlin16]

Many moons ago I had folders full of technical information.

Funny enough I never use them when hanging rads, pipe bending, gas rates, tightness testing or pipe sizing. ect.

Must be 'coz we do it so often that, experience come to play.

If you are already doubting your installers reckoning, god help him when he actually starts.

As for being shot of cash, that would worry me.

If that was me it would be, open door and bye bye.

 

[giblets]

I would be a little concerned about your CORGI man if he is letting you run the gas pipe which, I assume from your posts he is.

 

[Adrian80]

well unfortunately as i am not a millionaire, i have a budget, i think most people are like this, aren't they?

Fortunately anyone that has done work for me gets paid the day the job has finished, and after i have seen their work... I think this is fair, isnt it....

I thought sites like this were here to help educate everyone, i am always very grateful for everyones advice.

All i was asking for is how you calculate the correct gas pipe size...

 

[swidders]

Since your corgi man is signing it all off, it might be an idea to let him decide the specs. On the other hand, do it in 22mm and not have it signed off and without manufacturers guarantee.

Guess the choice is yours.

If you really want a bargain, there's another post on here about a recent installation which didn't seem too concerned about the regs. Get the op's installer's number.

 

[waterworks]

You could always run a new gas supply pipe from the meter to the boiler
Leaving your existing supply to feed your other appliances this way you will be able to use 22mm pipe to within 1 metre of boiler.

 

[Adrian80]

Dear all your getting the wrong impression, if i wanted to a non regs cheap job i would do it myself.

all i was asking was how you calculate the pipe size. If a 22mm pipe installation meets the specification then what would be wrong in signing it off?

i could feed every light switch in my house with 10mm twin and earth but it would be a bit of a waste of money..

i have just found a very usefull document which describes the process in detail.

http://www.ukcopperboard.co.uk/lite...ion-Tips/Domestic-gas-planning-and-sizing.pdf

which is all i wanted to know..

thanks for everybodys advice...

 

[swidders]

i could feed every light switch in my house with 10mm twin and earth but it would be a bit of a waste of money..

Apart from the two way switching Are you part P qualified

Glad you found out what you needed to know - hope he signs it off for you.

 

[Adrian80]

from the copper board doc, i did the calculations and it is just under acceptable for the use of 22mm , which means with the pressure drop to the two other appliances would guarenteed to be less than acceptable.

Also as boilers seem to get more and more powerful, it would limit the upgradeability.

Bugger knows why the previous installer, who was corgi registered, saw fit to plumb it in 15mm..

Good to know for defn..

Cheers Adrian

 

[Adrian80]

also to clear things up, i am not laying the pipe, just buying it....