Running a gas pipe HORIZONTALLY in a dot and dab wall

[stratplus]

How many of you do this? New build included. Just going to have a look at 6891 to clarify my current opinion.

 

[Killy Bing]

Hmm, i would say it would be classed as a cavity so a no no?

 

[IDCHAPPY]

What, as in behind the plasterboard? nope, I'd rather not

 

[stratplus]

Yes behind the plasterboard but solid dabbed around a wrapped pipe.

 

[buckley plumb]

most new builds have gas pipe wraped and fully enclosed in dab behind plaster board. som sites request steel ie on drops .

 

[stratplus]

horizontally though? Seeing it quite a lot recently by 4 or 5 plumbers. Regs only give guidance on cavity.

 

[stratplus]

BS 6891 (pipework) doesn't say that you can't run gas pipe horizontally but all pictured examples only show vertical pipework. I have just moved to a site where the whole gas carcass is ran horizontally around kitchen behind dry lining and they want me to do the same. I was always led to believe that pipework behind dry lined walls should be vertical only, wrapped and solid dabbed. Regs or standards don't seem to give me a reason to say I can't do it.

 

[jonnyswamp]

You can run gas pipe behind dot and dabbed plasterboard as long as the pipe is wrapped and fully encased with adhesive and takes the shortest possible route, but don't know if that applies to horizontal or vertical only
I'm sure someone will be along soon to quote the correct regs

 

[stratplus]

I have only ever ran it vertically, chased in to blockwork, wrapped, plated and solid dabbed. I always found an alternative route to drop vertically to avoid horizontal runs.

 

[Riley]

Interesting one I've come across a lot of these recently too

 

[lame plumber]

I'd run it in lcs to prevent nail damage

 

[IDCHAPPY]

Would you not have to vent the cavity so in the event of a gas escape there is a chance of it being detected?

 

[Riley]

That would've been my thinking IDChappy

 

[Killy Bing]

My understanding is with say boxing, you have to allow high and low ventilation to allow for leaks non detectible by the standard tightness test duration.

 

[Riley]

Agreed Billy had this exact situation the other day where there was a very gradual leak which was virtually non detectable but could easily have collected in the cavity but for a fortuitously placed vent.

 

[Destroyer2813]

The whole point of encasing it in the dab is so it isn't in a cavity is it not

 

[buckley plumb]

Would you not have to vent the cavity so in the event of a gas escape there is a chance of it being detected?

not if its fully covered in dab

 

[buckley plumb]

seen loads on site run horizontaly . I drop verticaly but not sure on the regs

 

[Ermintrude]

Bit like running t&e horizontally chimps do it all the time!

 

[stevetheplumber]

yes you can run horizontally has to be wrapped and fully encased in adehsive so there is no cavity to fill up my problem with this is will the dry liner actually do what his told to and its unlikkley youll still be around when its done so how do you sign it of

 

[AlexGas]

Here it is, from the BS 6891:

8.9 Pipes in walls

8.9.1 Pipe runs
Installation pipe shall, where possible, be vertical and shall be placed in ducts with convenient access points or placed in pipe chases.
The installation pipe shall be secured and have as few joints as practicable.

COMMENTARY AND RECOMMENDATIONS ON 8.9.1
Typical methods of installing pipes in walls are shown in Figure 6.

8.9.2 Cavity walls
Installation pipes shall not be placed within the cavities of cavity walls. Every pipe passing through a cavity wall shall take the shortest practicable route and shall be sleeved (see 8.10).

8.9.3 Dry lined walls

Installation pipes installed behind dry lining shall be suitably encased by building material.

COMMENTARY AND RECOMMENDATIONS ON 8.9.3
For typical examples see Figure 6b) and Figure 6c).

 

[AlexGas]

Where possible...
So, feel free!

 

[stratplus]

The diagrams referred to in 6871 only show vertical pipe runs. No mention of horizontal.
Corgi book says horizontal pipe runs should be avoided.

 

[stratplus]

What a pavlova!

 

[stratplus]

"where possible". Site plumbers usually on price so "which is the quickest".

 

[tamz]

You don't run them horizontally if it can be avoided but if it can't be avoided then you run them horizontally :smile:

 

[Riley]

One of those stupid "engineer on sites call" isn't it. Ambiguous at best. Ugh

 

[stratplus]

You don't run them horizontally if it can be avoided but if it can't be avoided then you run them horizontally :smile:

Conclusion as above.
Thanks all for your input.

 

[Reg Man]

Lets summarise: Perfectly simple, Only run pipes vertical. There is no excuse for making life easy or getting it done cheaper, but some circumstance's horizontal partial runs may be unavoidable.