Gas pipe under suspended floor - not permissible?

[Hilldes]

Plumber is on site and about to run gas pipe from plant room to kitchen island and concludes cannot run gas pipe under a suspended floor. Our floor is beam and block.  I have run yellow 110mm yellow gas ducting from plant room to kitchen island location. Plumber says can't run any kind of pipe under the suspended floor (including Tracpipe) even though the pipe will be run in the 100mm yellow ducting. 

 

Anyone encountered this and found a solution? Only option I can see would be to chase out several metres of concrete slab (and under the stud wall shown in pic) in order to run the pipe above the suspended floor.

 

[MikeGrahamT21]

http://www.tracpipe.co.uk/uploads/downloads/uk_di_guide.pdf

 

Everything suggests the plumber is correct as you would expect. States it cannot be installed below a structural element, and a floor classes as that. There is a section on ducting, and it states the ducting must be ventilated, but I think this is more for high rise. 

 

Take a look at page 66 also, and maybe ring their technical line? Seems to be another product which may be suitable.

[Hilldes]

Thanks @MikeGrahamT21, the plumber spoke to the Gas Safe technical helpline and another plumber that does a lot of new builds.

 

On the Tracpipe page 66 "Installation of TracPipe® within a secondary containment
We are sometimes asked for recommendations for additional piping (or secondary containment) to enclose TracPipe® when running through unventilated enclosures, ducts or voids. In the first instance we would always recommend investigating to see if TracPipeCC® can be used as an alternative solution or, if this is not possible, if the space or void can be adequately ventilated (see 8.8.3)." The void under a beam and block floor has to be ventilated, so I wonder if the plumber/Gas Safe are assuming the void is not ventilated, I'll check.

 

For plan B, talking to the plumber this morning, there may be a way to limit the length of chase to run the pipe in the slab - by running it up walls in the timber frame and through the ceiling void (which surprisingly is acceptable). But looking at the Tracpipe text, any chase into the slab (which is a structural concrete topping above an insulated beam and block floor), this may not be possible either:

 

"Pipework must not be installed in any location where, should there be a requirement to gain access to the pipe in the future, this could affect the structural stability of the building (for example within a structural screed or topping or within a structural timber floor)."

"TracPipe® and TracPipeCC® must not be buried in structural elements of the floor, such as concrete slabs or structural toppings".

[joe90]

Yes I was not allowed to run gas pipe under the house, had to run it around the outside and change from yellow plastic to metal as it entered the house behind the cooker (bottled gas only fir hob).

[Hilldes]

8 minutes ago, joe90 said:

Yes I was not allowed to run gas pipe under the house, had to run it around the outside and change from yellow plastic to metal as it entered the house behind the cooker (bottled gas only fir hob).

 Thanks @joe90, is there a void under your house and is it ventilated?

[joe90]

41 minutes ago, Hilldes said:

 Thanks @joe90, is there a void under your house and is it ventilated?

No. I wanted to run the pipe within the underfloor insulation.

[Hilldes]

7 hours ago, joe90 said:

No. I wanted to run the pipe within the underfloor insulation.

Bizarrely, if I interpret the Tracpipe document correctly that might be allowed. So in my case, it could not go in the void beneath the beam and block and it could not go in the structural toppling (slab) but it could go in the insulation sandwiched between them.

[Nickfromwales]

They basically want to avoid a situation where you have a compartment that can fill with gas, mix with air, and go ka-boom. You cannot run a gas pipe up a wall which is random dot n dabbed, but you can do that if the gas pipe is fully encapsulated in the dab from floor to ceiling. The point being, any puncture ( nail / screw / drill ) would only result in gas being discharged into the habitable space where it is assumed the inhabitants would smell it and realise there was a leak. For any other spaces or compartments where your nose would not be sniffing about, it's no-can-do.

I'd argue that pouring grout ( self levelling compound etc ) down that 100mm duct after pulling the Trac pipe through would satisfy that requirement, but then they'd ask you to prove that every inch of the pipe had been successfully encapsulated. Bit tricky that one. 

 

I'd check though, as the void is ventilated so it's a bone of contention.

Edited September 3, 2021 by Nickfromwales

[Hilldes]

Thanks @Nickfromwales will check on the ventilated void position next week.

[AliG]

I had to do the same as @joe90

 

The regs massively increase the cost of using gas.

 

Simple solution is an induction hob ?

 

 

[Ferdinand]

6 hours ago, AliG said:

I had to do the same as @joe90

 

The regs massively increase the cost of using gas.

 

Simple solution is an induction hob ?

 

 

 

Sounds like it.

 

Learning from the Olympic bicyclists .. marginal gains on gas usage.

[joe90]

7 hours ago, AliG said:

I had to do the same as @joe90

 

Simple solution is an induction hob ?

 

 

Which is what I wanted but “er indoors “ wanted gas ?‍♂️

[Nickfromwales]

11 hours ago, AliG said:

The regs massively increase the cost of using gas.

….but are advantages in not allowing you to cheap out and blow yourself into the next borough  

[Dave Jones]

Not really much help but the pipe needed putting in before the beams went down, you could have ducted and concreted it to come up under the island so it was sealed.

 

Always have to think 10 steps ahead.

[Hilldes]

14 hours ago, Dave Jones said:

Not really much help but the pipe needed putting in before the beams went down, you could have ducted and concreted it to come up under the island so it was sealed.

 

Sealed in what way? The yellow ducting was put in before the pre-stressed beams went in - although not the pipe.