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https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl DIY Forum >> Plumbing Questions >> Using MDPE pipe https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1107824429 Message started by oggy on Feb 8^th, 2005, 1:00am

Title: Using MDPE pipe
Post by oggy on Feb 8^th, 2005, 1:00am

I need to run a length of 20mm MDPE pipe undergound for a garden tap.

To supply it, I will tee into the 15mm copper pipe supplying an existing outside tap. This supply contains a double check valve and can be isolated inside the house.

This leaves me with a few simple questions which hopefully you helpful chaps can answer:

1) are there any rules/regulations I need to follow for this type of installation?

2) how deep should the pipe be buried? (It will run under a patio so there's no chance of putting a spade through it!)

3) I understand that MDPE should not be left exposed to the elements, so should I make the change from copper to MDPE underground?

4) how are the 20mm MDPE to 15mm copper adapters like Screwfix item 16638 fitted? Are they simply push fit or are other parts required too? Also are they suitable for an underground joint?

5) last but not least, what do I need to do to protect it from freezing?

Thanks..

Title: Re: Using MDPE pipe
Post by billythekid on Feb 8^th, 2005, 11:28am

if its buried you wont need to worry much about it freezing, lag the exposed bits at the ends or whatever.

I'd use copper all the way but theres nothing i know of to stop you running mdpe all the way, or running exposed in copper. If your gonna lag anything above ground it wont be exposed to the sun etc.

That fitting you mentioned goes inside your mdpe compression fitting as an insert to change from mdpe to copper.( i think, my screen is buggered here so i cant quite see it clearly)

Cant remember the depth, 400mm rings a bell but scruff or someone will correct me on that. I remember something about 6" below for frost protection but just cant think off hand the actual reg. (It is on the forum somewhere as has been asked before)

btk