Plumbing - Water flow rate Copper Vs Plastic?

DannyW · 31 Mar 2015 at 12:57

Hi guys I am just ripping out some Lead pipe which I found buried in a wall, it was the hot and cold feed to my bathroom

A few plumber mates said just swap for Plastic pipe for ease

To cut a long story short I bought some pipe today and inserts and with the inserts in the bore of the pipe looks tiny.

Would I achieve better water flow rates to the bathroom by using copper pipe? I would like to get the full potential out of my shower

DWH is from combi boiler

Kiyoshi · 31 Mar 2015 at 13:16

This is a bit anecdotal but we had our bathrooms redone and the flow rate after they'd finished was noticeably worse. It was fine before the work, I can only assume they used plastic piping re-doing it as I can't think of anything else that would cause it.

Bickaxe · 31 Mar 2015 at 13:38

Plastic pipes can be glued (compression fittings available at all good and bad stockists) so it's quicker and cheaper to put a system in. We went with copper as it can bend and soldered the joins. We have fantastic pressure though so that helps.
Waste pipes are plastic.

I don't know if a separate pump will help, never has cause to use one.

DannyW · 31 Mar 2015 at 18:13

Did the swap over from Lead to Plastic this afternoon, flow up stairs is nearly twice as good so I'm happy

FlyingFish · 31 Mar 2015 at 19:32

If you have good water pressure and nothing bigger than a four bed then use plastic. You could always use 22mm. Otherwise use copper, insulate it, and keep the pipe runs short, machine bends are better than fittings. If you have a larger property than you shouldn't have a combi IMO.

Mick

Ronty · 31 Mar 2015 at 20:49

Bore differences between plastic and copper of the same size (i.e. 22mm) are fractions of a millimeter, so will have next to no difference on flow rate.

If you have issues with new installations its most likely due to pipes being undersized, excessive use of restrictive fittings (like elbows) or flow reductions through valves or outlets.