On 26/05/2021 14:00, Dave Plowman (News) wrote:
In article ,
Steve Walker wrote:
On 26/05/2021 12:51, Fredxx wrote:
On 26/05/2021 11:56, R D S wrote:
On 25/05/2021 11:48, fred wrote:
Serious explosion bellied caused by cut gas pipe. How ? Presumably
it was in error but what would you be doing for that to happen?


We've no gas to our kitchen (meter at opp end of house) and I've
never been motivated to rip up the floor throughout to sort it.

My neighbours have taken a pipe out of the meter cupboard door and
run it along the floor/skirting.

I don't think you can route a new gas pipe under floorboards.

I'm pretty sure you can.

My understanding (not that I actually have anything to do with gas) is
that a new supply pipe to the meter should not be routed under the
property, but for pipes after the meter - under a suspended ground floor
is fine (it is classed as a ventilated space), while, in an
unventilated floor/ceiling void needs a surrounding sleeve, with one
end sealed and the other end open to a ventilated space.

Bit of a dichotomy. A properly made concealed gas pipe is far less likely
to get damaged than a surface run one.


Transco gas pipes enter under the garage slab and are mild steel
3/4 inch pipe, painted with black bitumen paint and held inside
4 inch salt glazed pipes to physically isolate them from the subsoil.
From the meter 'my' pipes are the same 3/4 iron also inside a 4 inch
glazed pipe passing under the concrete path and coming up inside the
lounge adjacent to the false chimney breast where the baxi back boiler
used to be. The 3/4 pipe continues, buried in the 80mm screed around
to the kitchen where a T fitting provided a 1/2 inch outlet for a
gas fridge and another 1/2 inch run of iron, all burioed in the screed
to the cooker point. Cutting or drilling any of that is pretty
difficult.

Surface corrosion of the 3/4 inch iron pipe under the garage slab
or under the concrete path is going to happen at some point. I did
a trial excavation to see what condition it was 10 years ago and
there are many places where rust is bubbling under the bitumen
paint.