sleeving through recessed meter box?

[gazza191]

Hi there, just installing a new boiler in a boiler room and the gas pipe comes straight through the wall from a recessed meter box and through the back of the box. should the pipe and sleeve be sealed on the inside of the box and left open around the sleeve on the boiler room side to allow gas to escape if it leaks in the wall or vice versa as you would normally leave the outside open to allow gas to escape? any help appreciated.

 

[REDSAW]

is it a domm installation?.
best off re-routing out the side of the box.imo.

 

[rm1]

if you read your regs you would know that this current set up is classed as "at risk" you are not allowed to go through the back of a recessed box you will need to renew the gas pipe to exit the meter box through the bottom and then into the property with an appropriate sleeve sealed in the inside only,are you a registered engineer because this is basic stuff

 

[gazza191]

yep gas safe registered and i have seen this set up loads of times with the pipe normally sealed with the fire proof putty on the inside. it shows this arrangement in my viper gas book? it is a domestic install.

 

[REDSAW]

well, i have got one the same tomorrow to alter the internall pipes.
not sure if to redo the meter connections too to bring them to standard but access is dificult.

 

[tamz]

It would only be AR if it was a medium pressure rig or there was no sleeve.
Seal it on the inside as usual and make sure the outside of the sleeve is sealed to the box.

 

[gazza191]

ok just to clear this up is it against regs or not to go through the back of the box as im a bit worried ive missed something here. recessed boxes have their own knock out so i always guessed this was ok and havent heard otherwise?? if it is ok i will be sealing the pipe
and sleeve inside the box with putty and just the outside of the sleeve inside the building? correct or not?

just to add it is a low pressure meter not medium.

 

[rm1]

is it medium pressure yes or no

 

[gazza191]

no its not

 

[tamz]

Medium pressure is not afaik fitted in recessed boxes.

It is ok and allowed to exit through the purpose provided knockout on a recessed box. Just seal it on the inside (of the box) and make sure the sleeve is sealed to the box.
The best stuff to use is Densoseal16A available from your local transco or utilities guy if you speak nice to him or you can use that plumbers mate type shyte.

 

[rm1]

its your call but imho i would alter the gas pipe

 

[gazza191]

thanks for your help guys but i'll give gas safe a tinkle tomorrow as i seem to be getting conflicting advice here.

 

[tamz]

its your call but imho i would alter the gas pipe

Why?

FYI from IGEM UP7



and



It is also in another IGEM but i can't remember which one and can't be bothered looking for it.
It is also in your viper (chapter L) or corgi books or whatever manuals you own.

 

[gazza191]

thanks tamz, so would i be sealing the sleeve and gas pipe inside the box to the spigot ( no gaps at all and using the fire resist putty) and then just seal the sleeve to the wall inside the buliding with a gap between the pipe and the sleeve so gas can escape in the event of a leak or have i got it the wrong way round? normally when sealing a sleeve gas is meant to escape to outside the building. this is why i'm confused?

 

[tamz]

Seal the inside of the sleeve inside the box and make sure the sleeve is sealed to the box too. A bug lump of denso mastic or whatever non setting mastic you use does this.
Here is another picture from the viper book.



The only time you can't exit the back of a recessed box is if it is a medium pressure.

 

[gazza191]

this is exactly the scenario i have got as per the right hand pic. i get that everthing needs to be sealed up inside the meter box now but as i pass through the wall and into the building this end of the sleeve needs to be left open to allow gas out in the event of a leak? this is opposite to normal as normally the inside is completely sealed so gas escapes to outside? so do i leave the inside open? thanks again for your help and again i am not dealing with medium pressure as i know you cant use this meter box with medium pressure .

 

[AWheating]

take a closer look at the pictures tamz has posted. You have the two different situations with pipework either surface or inside the wall/plaster.

you will need a tub of fjc non setting compound, normally around £6 to £8 per tub.