Energy-dissipating manholes consist of a hemispherical, PEMD moulded base, obtained via a rotomoulding process.
As the inlet and outlet couplings can be created at different heights, the special shape of the manhole makes it possible for effluent at the outlet to be slowed down.
For this reason, energy-dissipating manholes are generally used where a sewerage pipe is located on steep slopes.
Ends of manholes with risers can be created using a PEMD conical reduction adaptor, obtained via rotomoulding and coupled onto the extension, which is used to reduce manholes up to a crawl space diameter of 600 mm.
A ladder, consisting of polyethylene uprights and polyethylene-coated steel steps, may also be welded onto the inside wall of the risers.