Plumbers NZ is New Zealand's largest online plumbing, gas and drainage resource. Plumbing exam help, plumbing news, directory and free quotes.
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
Powell Fenwick