On 2006-10-08 19:40:35 +0100, "Black Shuck" said:

Doing a new kitchen myself, thought to be on the safe side, got a Corgi
registered company to sort the gas out.

However, I think they may have done unnecessary work.. Thought I'd ask
here to see what others think..

My existing gas point basically needed moving 1 metre, from 1 wall, to t he
corner of the same wall. I lifted the chipboard ready for the gas fitte rs
arrival. On arrival however, he explained that a 13mm gas feed is
insufficient for a double gas oven and 5 hob gas stove, and needed a 22m m
feed, pointing to the underside of the combi-boiler, as an ideal spur. I
kinda went with his recommendation.

A couple of days back, they came back to do the work (I had to remove
additional bits of the old kitchen to facilitate running the new pipe,
hence the delay).

To my suprise, they ran 22mm from the boiler halfway along the wall, the n
fitted a reducer down to 13mm, then another meter, did a 13mm spur for m y
hob, and the rest of the feed in 13mm.

Crude pic he

http://picasaweb.google.com/lh/viewP...llespie&aid=49
83589095688241169&iid=4983590944950910994


How does this differ from the original setup of extending the original
13mm pipe installation? Surely the flow is restricted by the smalled
pipe? So even the new setup is limited by the last run of 13mm pipe? I
would have understood things, if they T'd off the 22 with 2x13mm spurs,
but they did not...

Have they created unnecessary work???

This is a case where length matters.

Resistance to flow depends on pipe lengths and fittings as well as diameter.

Take a look at this

http://www.cda.org.uk/megab2/build/pub124/sec3.htm

The design may well be reasonable.

The acid test would be to make pressure measurements at the meter and
the two appliances and to check that there is not more than the allowed
1mB drop in pressure.