Replacing complete foul & ran water system, brick built Drainage and wastage systems and plumbing help, advice and answers

[Trevor McAlister]

Hi
I’m completely replacing my foul & ran water system right back to the first inspection pit, this is the easier option to making multiple connections into existing cast iron & clay pipe work. (It’s only one soil stack & 3m of underground pipe more than I would have had done any way.)

I just wanted some reassurance that I will be doing the work in the correct manor, this is the first full set of drains I have done but I am an advanced DIY’er/renovator. And before you ask building control have been informed and will be inspecting pre & post back filling.

The actual Pipe work is pretty straight forward; one new 5 way inspection pit, one 90 deg inspection pit, two upstairs bathrooms each with its own externality vented soil stack, one under stairs toilet with air Admittance valve. Gray water from kitchen, gutter down pipe & surface drain, each through its own or shared bottle gully.

My question relates to the first inspection pit off the road, which is brick built with clay pipe running through the bottom with benching ether side (no branches joining), it also has a mains derange rodding point & trap.
Due to the repositioning of gutter down pipe, addition of surface drains and the requirement to have all braches rodable, I need to add two branches (carrying rain water only) to one side of this inspection pit.

Although I have never constructed one of these old style inspection pits before, I am familiar with the requirement of having a radius on the end of the branch pipe so it doesn’t just hit the posit wall, and pointing the branch in the same direction of flow as the base pipe. I have read through the Approved Document H but this doesn’t give any requirements that are relevant to particularly type of inspection pit.

I’m after finding out what particular things a building inspector or professional builder would be looking for in a job that is done well. I have access to a library in the local technical collage if you can recommend a good book on the subject.
Or just some tips from some one that is experienced with brick built inspection pits.
Trevor

[stoneyboy]

Trevor McAlister,
If you can find a couple of clay 1/2 swept bends these would form the gulleys in the inspection chamber. If the invert is deep enough you could set the bends ontop of the benching, if not you will have to angle grind two channels in the benching with corresponding holes through the brick sides.
Many water authorities will not allow rainwater to be fed into a foul drainage system - may be worth checking even if this is what happens now.
If you can find 'drainage details' by Leslie Wolley (ISBN71982520 2) this is a good source of information
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