dennis@home wrote:
"Tim Downie" wrote in message
...

"dennis@home" wrote in message
...


"Tim Downie" wrote in message
...
I was recently told when a plumber cut off a dead leg in our gas
pipework that we had a small (but allowable) leak in our system.

Clearly he wasn't wild about chasing the leak but I'd rather
there wasn't one. Before I start hunting, what's the
acceptable leak level in mbar/min?

Zero!

No such thing as zero. That would mean waiting infinitely long to
prove that there was no leak.

Unless you know the gas is being vented to the outside air how do
you know it will not go *BANG*?

Funnily enough, I have a nose. It's proved a lot more reliable
than BG gas fitter's testing proceedures.

Well there is your first error.. to smell it means it has to be
escaping into the room, what about the roof/floor/wall spaces where
you don't stick your nose.

Actually, I *do* stick my nose under the floor and into the loft. Haven't
got any joints in my wall cavities.

It may take weeks or months to build to an explosive mixture but
how do you know it hasn't?

If we were talking about LPG, I would worry more but natural gas
has a lower density than air, so it's less inclined to lurk.

Checked your roof space recently? ;-)

See above.


LPG is very dangerous on boats as they tend to be gas tight and there
have been some very big bangs.

Why are you telling me something I already know? I'm trying to make the
point that a lighter than air gas is most unlikely to "take weeks or months"
to build to an explosive mixture in a typically ventilated house. I'll
wager that every gas induced house explosion with natural gas has been due
to an accummulation *much* faster than "weeks or months".

Like I said any leak is dangerous unless you know where it is going.

Leak tested your own pipework and appliances lately? Or do you trust
someone who's in a hurry and *doesn't* live in the same property as he/she
is testing?

Tim