Replumbing - Copper vs Plastic pipe?

[Spoilt Victorian Child]

I asked my builder to replace the lead mains water pipe in my house. It ran from the front door to the back of the kitchen (approx 14 meters) in the cavity under the floorboards.

I've just looked under the floorboards and was surprised to see he'd done the whole run in 15mm copper pipe.
I was expecting it to be done with the thicker blue plastic pipe.

Is using 15mm copper pipe ok for this type of thing? (I'm worried about very cold winters).

I don't know what the internal diamter of lead pipe is, but could the 15mm copper pipe also explain why my shower pressure is unimpressive?
(The hot water is coming from a new boiler which was installed at the same time, so I'm not sure if the drop could actually be down to the boiler.)

 

[Lewis Tiffany]

Nothing wrong with copper pipe better for you than plastic blue plastic pipe .
I would get it covered with thick pipe insulation

The internal pipe diameter and flow rate between 20mm and 25mm blue plastic is not much more than 15mm copper by the time you put the pipe inserts into the plastic pipe .

Check to see if the stop taps are turned on full outside in the street and in the property where it comes up into the house

Have a look at the hot water flow rate on the the boiler
Some of the lower end range boilers do have very low flow rate should be shown as litres per minute 8 poor 16 good . it could also be the shower required a minimum flow to work correctly if the boiler can't supply this it will struggle

You usually should get a better flow rate with a new pipe compared to a lead pipe as lead pipes can have a internal diameter from 8mm up to 15mm depending on the weight of the lead used most are about 10 mm

You can also ask the utility company to check the flow rate .

 

[Lewis Tiffany]

Nothing wrong with copper pipe better for you than plastic blue plastic pipe .
I would get it covered with thick pipe insulation

The internal pipe diameter and flow rate between 20mm and 25mm blue plastic is not much more than 15mm copper by the time you put the pipe inserts into the plastic pipe .

Check to see if the stop taps are turned on full outside in the street and in the property where it comes up into the house

Have a look at the hot water flow rate on the the boiler
Some of the lower end range boilers do have very low flow rate should be shown as litres per minute 8 poor 16 good . it could also be the shower required a minimum flow to work correctly if the boiler can't supply this it will struggle

You usually should get a better flow rate with a new pipe compared to a lead pipe as lead pipes can have a internal diameter from 8mm up to 15mm depending on the weight of the lead used most are about 10 mm

You can also ask the utility company to check the flow rate .

 

[88v8]

Copper is fine provided it's buried 3 ft in the ground.

Ivor

 

[Spoilt Victorian Child]

Hmmm... mine is is only 1ft below my floorboards, with all the other service pipes (gas, electricity, etc).

 

[eezageeza]

If your only worry is the pipes freezing, then I'm pretty sure you'll be fine - the pipe would have to be at sub-zero temperatures for some time to freeze, and I don't imagine it will ever get anywhere near sub-zero under your floor.

 

[88v8]

Ahh, OK, I hadn't read it properly. In the house, usually no problem, unlikely to freeze.
If the underfloor is well ventilated it can get pretty cold down there, but unless you're living somewhere particularly parkey it shouldn't be a problem.

However I always put insulation on pipework, apart from anything else it quietens it down. There seems to be a trend towards high-pressure systems with everything run off the mains so that whenever one turns on a tap or flushes the khazi, a din ensues.

Ivor

 

[Lime]

Ahh, OK, I hadn't read it properly. In the house, usually no problem, unlikely to freeze.
If the underfloor is well ventilated it can get pretty cold down there, but unless you're living somewhere particularly parkey it shouldn't be a problem.

However I always put insulation on pipework, apart from anything else it quietens it down. There seems to be a trend towards high-pressure systems with everything run off the mains so that whenever one turns on a tap or flushes the khazi, a din ensues.

Ivor

Frozen pipes can occur even inside a house if it gets cold enough.
It is always a good idea to insulate them.

As for water noise in pipes, I've said this before but I'll say it again because a lot of people have a hard time taking it in, if copper pipes are installed under stress or tension they will be far noisier than if installed with no tension in them.
I discovered this years ago but it is not commonly appreciated.
When copper pipes are installed the unions/connections should be made in such a way that the pipework has no twist, tension or compression on the pipe.
The copper pipe must be relaxed and shaped so that the fittings slip on and align perfectly.
Otherwise the pipe will behave like a taught violin/guitar string and transmit sound.
Rather like the childhood "telephone" toy of 2 tin cans with holes in their bottoms connected together by a length of string.
They don't transmit noise until the string is taught.

 

[DJH]

Yes Lime you are quite right. Over clipping or fixing can exacerbate the problem and also cause water hammer when taps are shut off quickly and ball valves are just closing.
I remember being taught that copper pipe should be cut using a hacksaw rather than tube cutters which leave an internal burr that causes turbulence when water passes through the pipe. I never gave much credence to this being young but maybe there is some truth in it...

Doug

 

[agbagb]

The worst thing I've found for exacerbating pipe noise are all these isolating valves we have to fit. Standard ones and those on flexi couplings are narrow bore, so the pressure drop across them creates loads of noisy turbulence. Full Bore ones are available and can make a big difference.

 

[Owain]

if you're really worried about pipes freezing you can put electric heat trace tape round the pipe and then insulate it.

 

[chuckey]

Combi boilers have a restriction on their flow, else the hot water would be warm water.
Frank

 

[Lime]

Yes Lime you are quite right. Over clipping or fixing can exacerbate the problem and also cause water hammer when taps are shut off quickly and ball valves are just closing.
I remember being taught that copper pipe should be cut using a hacksaw rather than tube cutters which leave an internal burr that causes turbulence when water passes through the pipe. I never gave much credence to this being young but maybe there is some truth in it...

Doug

Also if copper pipe is annealed before the joints are made it is even more quiet.
Particularly true if the pipe has been worked by bending and shaping.

 

[MatthewC]

..In the house, usually no problem, unlikely to freeze...

Frozen pipes can occur even inside a house if it gets cold enough.
It is always a good idea to insulate them.

The 1999 house (which we rented while doing this house) was awful - the kitchen floor was always really cold even in July, the uPVC DG had draughty gaps and in the cold 2010 winter the hot water supply from the boiler to the bathroom would freeze overnight. I don't know where they had routed the pipes and I reckon they economised on the underfloor insulation.