Drain pipe coverings

[Vijay]

I really can't get my head around the bit in part H where is shows the covering over 110mm plastic pipes (pages 17,18 and 19). BCO came round today and is happy with the drainage so far but he said I need to concrete over the shingle where I will be driving over - but I've wondered if he said that looking at the ground level at the moment rather than the finished ground level.

 

Is there a minimum depth from FGL to the pipe that would require concrete or is it standard practice to concrete over the shingle no matter how much backfill is on top of the drainage pipe where it will be driven over?

[Barney12]

According to the Orical that is http://pavingexpert.com/drain02.htm

 

900mm for plastic. 

 

See 'gradients and cover'

[Vijay]

Found the answer although the BCO just wants 6" of concrete on top of the shingle rather than the pipe enclosed:

 

 

Minimum cover over plastic drainage 600mm in fields/gardens 900mm beneath light roads/drives     Minimum cover over clayware drainage 300mm in fields/gardens 400mm beneath light roads/drives
Encasing in concrete: Note: If minimum cover cannot be acheived, the pipework will need to be encased in concrete. Any pipeline beneath a road that has less than 1000mm of cover, must also be encased - see diagram opposite. A full width/height movement joint consisting of 13mm compressible board is typically included at every joint, although this may be changed to every alternate joint in some cases. In many applications a so-called 'lean-mix' (something like a GEN1) concrete will be used for this work, but when there is concern about loading on the pipework, then a higher-strength C20 equivalent (FND2), or even stronger, concrete would be used.

[Vijay]

Cheers Barney, found it at the same time