Insulating external water pipe

[WWilts]

New build in progress

32mm MDPE about 7m runs externally on footings (about 500mm below eventual ground level)

 

How to protect vs freezing?

Would 25mm rockwool insulation suffice? Within 100mm rigid duct

[Simplysimon]

if it freezes at 500mm deep then probably russia dropped a few nukes and we're in an arctic winter.

[JohnMo]

24 minutes ago, Simplysimon said:

 arctic winter.

Or a nuclear winter

[jamieled]

Our external water pipe is about that depth and not insulated. We live in a relatively cold part of the UK. We don't have any problems with that section of pipe.

[saveasteading]

Frost doesn't really go lower than about 400mm in UK  except in exceptional locations.

Even then, it would be very short term and the water has a reasonably high temperature unless coming out of a snowy hillside.

 

No, it needs no insulation, and certainly not rockwool which would get wet and horrible.

[WWilts]

17 minutes ago, saveasteading said:

rockwool which would get wet and horrible.

foil wrapped, with sealing flap. 
But point well taken that at 500mm below ground level insulation probably not needed.

[Thorfun]

our mains water pipe runs at about 450mm for a short distance and I was asked by Southern Water to insulate the 32mm pipe. I ended up using this https://www.bes.co.uk/shalloduct-water-service-pipe-insulation-835-x-25mm-18496/?gclid=Cj0KCQjw0umSBhDrARIsAH7FCofPjZE97Kx-4mMkVt_XlLonwlnjcnnNwOdcUPzvCi3Hia-Kj6K4GNcaAsfpEALw_wcB  inside a blue ducting pipe https://www.bes.co.uk/shalloduct-rigiduct-insulation-pipe-blue-4-x-3m-18515/?gclid=Cj0KCQjw0umSBhDrARIsAH7FCofHqPbJ8g0a1CYXl9oau7cmHLaitE7Z2nweE57W5fsHLg6M2PsHocwaAlcKEALw_wcB which they were happy with.

[jayc89]

IIRC, Yorkshire Water ask for anything above 750mm to be insulated. We lagged the pipe as it entered the building and came up beyond that 750mm threshold (basically the length coming through the rest bend), but that's it.

[saveasteading]

I've been doing this a long time and had not come across any such ruling (and never had a problem).

 

But some of Yorkshire is high and exposed and perhaps it is simplest to apply a single ruling regardless of location.

Southern Water though?

 

My house water (SE) comes in at about -300 (including the meter installed by the water company) and has survived some very vicious winters (to -18C).

 

 

I found this from J D Pipes.   No mention of location or circumstances.

Avoid freezing pipes

According to 'The Department of the Environment', they recommend that pipes should be buried at least 600mm (two feet) underground. At this depth, the soil acts as a natural insulator and prevents them freezing.

 

A deeper trench will likely be cheaper than insulation, if necessary where you are.

For a long run in open ground there are ploughs that make a slit and drop the pipe in one easy operation. But I don't think they reach 600mm.

 

[Simplysimon]

2 hours ago, JohnMo said:

Or a nuclear winter

yup, i was trying to think of that but a long day cladding a dormer side off a roof ladder and shifting scaffold, just went blank.

[TonyT]

Bury pipe to required depth in trench

insulate pipe from bottom of trench to inside house.

climaflex insulation is pretty much available everywhere 

[Johnny Jekyll]

May I jump in and ask what's best to seal the end of the flexiduct/pipe after inserting the insulation? My supplier say to "seal the ducting with a non-petroleum-based product".

Should I be using CT1 or expanding foam filler?

Any links to specific product to buy would be very helpful thanks.

 

Edited April 25, 2022 by Johnny Jekyll

[PeterW]

Cheap and cheerful acrylic sealant will do