Is there any advantage in insulating 22mm Hep2o pipe?

[Mr_T25]

We have a large home and the 22mm plastic pipe that feeds various bathrooms around the house (longest length of pipe will be around 30m before it reaches the bathroom) as well similar sized pipe being used to route water to various manifolds around the house for the underfloor heating.

I know the pipe will not suffer the heat same loss as copper, but for the sake of a few pounds, is it worth doing? How warm does (heat dissipation) does Hep2o pipe get on the outter surface?

 

[motorbiking]

it should be insulated if it's running in a void as per building control. It's more important to insulate the heating pipes.

a couple of 30m runs in a cold void will lose about 1-1.5kw.

 

[endecotp]

Yes, you should absolutely insulate it!

The thermal conductivity of hep2o is apparently 0.22 W/mK. (http://www.tglynes.co.uk/downloads/tgl-coshh-tech-hep20-performance.pdf)
Consider a 1m length of 22mm diameter pipe containing water at 60C, with ambient temperature of 20C.
The surface are of that pipe is approx 0.07m. Thickness is something like 2mm (?).
So heat loss = 0.22 x 40 x 0.07 / 0.002 = 300W.

Actually it's not as high as that. That's what would happen if you immersed the pipe in e.g. water at 20C which would efficiently carry the heat away. If it's in air, it is limitted by how fast the heat can be convected away from the outside of the pipe.

The doc I linked to above specifies required insulation in tables 8 and 9.

 

[Mr_T25]

hmmmm ok. Some of the pipe will be running in the loft void near the eaves (loft area is converted) but the loft has been well insultated with 150mm of kingspan. Unfortunately they didnt put any pipe lagging where ir runs up a vertical part of the wall to get to the loft so whilst the void is insulated it wouldn't have hurt to add more lagging.

What sort of lagging should I be using i.e. what should the outter covering thickness be? Obviously the thicker the wall the better, but would 13mm cut it or 19mm like this one?
http://www.wickes.co.uk/Wickes-Pipe...dc|pcid|102693174652|pkw||pmt|{BidMatchType}|

 

[endecotp]

See the tables in the document I linked to.

 

[ey143]

25mm? Seems a lot doesn't it.

How do you handle the areas around the clips etc. Ive got loads of them holding the pipe down.

 

[gasmanstu72]

lag the pipe first then secure it with some galband, that's what i do for pipes that should be lagged

http://www.screwfix.com/p/galvanised-band-12mm-x-10m/18298

 

[SandyLyon]

You should insulate plastic pipe as you would copper

 

[motorbiking]

You need the bylaw compliant stuff. It would have been easier to slide it over during install, but it will clip around easy enough.

I'm assuming this is the work of a qualified professional plumber ? it seems common to forget this important part of the job

 

[Mr_T25]

It was yes, but I dont know many people who use the pipe lagging stuff for pipes that run inside the ceiling voids across rooms etc which is where the majority of my Hep2o pipes will be running.

 

[motorbiking]

if it's between ground floor and first floor then the heat is not really lost. Insulating hot tap pipes can save water as they run off less before getting hot, but it's nothing compared to having a radiator pipe running under your ground floor in a ventilated void.

 

[Steelmasons]

lag the pipe first then secure it with some galband, that's what i do for pipes that should be lagged

http://www.screwfix.com/p/galvanised-band-12mm-x-10m/18298

Cable ties look neater and a hell of a lot quicker.

 

[Agile]

The laziness of installers is amazing. Virtually none ever lag hot water pipes and only a very few lag heating pipes.

If you have a 30m run to hot taps then you should really have had a loop system with a pump so you get instant hot water at every tap! Just like ( most ) hotels!

A builder at a house where I was doing some installation work recently told me that one of the pipes to the kitchen which I had installed under the floor had "disappeared". I went with him to look. The "disappeared" pipe had just been insulated since he last looked and so was not obvious against the ground under the floor!

Tony

 

[Mr_T25]

The laziness of installers is amazing. Virtually none ever lag hot water pipes and only a very few lag heating pipes.

If you have a 30m run to hot taps then you should really have had a loop system with a pump so you get instant hot water at every tap! Just like ( most ) hotels!

A builder at a house where I was doing some installation work recently told me that one of the pipes to the kitchen which I had installed under the floor had "disappeared". I went with him to look. The "disappeared" pipe had just been insulated since he last looked and so was not obvious against the ground under the floor!

Tony

Not if the bathroom in question is rarely going to be used and the amount of energy and heat loss used to circulating the water in the secondary loop is going to outweigh the benefits.