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Hey guys,
I’m after some advice on the typical clearance required for WC waste pipe installations.
I’m working on a project with a 125mm thick floor slab, with a lattice of ground beams below the slab. A WC with a 100ø PVC waste sitting over one of the ground beams is shown in the sketch attached/below.
Currently the structural engineer has allowed 300mm from the top of the floor slab to the top of the ground beam (the measurement labelled ? on the sketch). This allows 175mm clearance within the ground between the floor slab and the ground beam.
• What is the recommended minimum length of straight vertical pipe from the bottom of the WC to the top of the 88° Bend (female & female socket ends)? Or does it not matter?
• Is it better to have the entirety of the 88° Bend below the slab?
o Similarly, are there any reasons to avoid casting a portion of the socket end of the 88° Bend within the slab?
• What is the recommended clearance above ground beams like this? Is 50mm adequate?
Can you please also offer advice for whether your answers will apply to 40ø, 50ø, & 65ø wastes penetrating similar slabs too.
Thanks for your help!
Robbie Peacocke
Hydraulic Engineer
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