Underground pipe

[WhydidIstart]

Hi, I have recently moved into a new house and replaced the outside tap as the old one was damaged and didn’t have a check valve installed as the pipe just came straight off the kitchen tap supply. I got rid of what was there and fitted a dishwasher connection point, new connection to the kitchen cold tap and double check valve + isolating valve that feeds the outside tap. I would also like to send a feed into a concrete shed in the garden about 5 meters away. My questions are what regs do I need to follow to be vaguely in compliance and not have the pipe freezing in the winter!

# I would like to use 15mm plastic pipe and bury it in the ground. Is this ok and how deep does it need to be please?

# Are push-fit connections reliable for outside use? I have heard they are generally pretty good and might be less likely to burst in the cold as they are better insulated than copper pipes and can tolerate more expansion of ice in the pipe than copper.

# Finally can they go straight in the ground or do they need to be inside some form of conduit?

Any help much appreciated.

 

[Slugbabydotcom]

Only guaranteed way is to treat it as a service pipe.

Bedded in sand 750mm deep. Sleeved under the foundation of your house and through the concrete shed base.
A stopcock should be fitted before and after it goes under ground.
20mm Alkathene should suffice. Try to avoid having any joints below ground.
don't forget to use support sleeves in the joints.

There are other physical ways of doing it with boxing, insulation and perhaps even trace heating. You could even come up with a way of temporarily connecting a hose pipe, but if you want a permanent hassle and running cost free supply in your shed when its below freezing there's only one sure way of doing it.

 

[chrishutt]

That's the theory. In practice 20mm blue MDPE buried to a reasonable depth and insulated where it's near or above ground level will be fine. There are thousands of examples of uninsulated above ground pipework around which seem to survive winter after winter (they aren't what they used to be). Even the Water Company contractors don't bother going down to 750mm depth. The requirements of the regulations are based on expectations of some sort of mini ice age rather than global warming.

 

[WhydidIstart]

OK, thanks for the quick replies. It sounds like it will be low risk to bury it a fair depth but not 750mm and insulate it where it could be exposed to cold conditions. It wouldn't be the end of the world if I had a leak where it is located.