On 03/09/2012 11:11, Paul D Smith wrote:
"David WE Roberts" wrote in message
...
Any benefit in running a 22mm 'backbone' with 15mm spurs to endpoints?

Theoretically this seems to give a higher overall capacity but I don't
know if this is necessary for normal use for basins, toilets. etc.

Personally I'd look at it the other way around, "any reason not to"? If
the cost difference is not great (and I've not done plumbing for a while
so apologies if it is), over capacity seems a reasonable aim - doesn't
guarantee future proof but perhaps puts off obsolescence a little.

Paul DS

Having just replaced a cold water loft tank, CH expansion tank in loft,
and plumbed in a digital mixer shower - I discovered that (at Screwfix,
and also at B&Q) 22mm copper pipe is £19.99 for 3m. 15mm copper pipe is
£9.99 for 3m. Whether that's the cheapest you'll get I don't know
(think it gets to £14.99 for 3m if you buy 30m at Screwfix!), but after
discovering this price difference, I quite happily plumbed the last 6m
to the shower (3m of cold pipe, 3m of hot pipe) in 22mm SpeedFit.

I was surprised at the cost of 22mm copper pipe!

D