Manholes created from pipes are made from Ecopal corrugated or smooth polyethylene pipes that are cut and welded together.
Manholes can be made with a channelled base if a pipe runs through it, or with a flat base if it does not. In the former, the insertion of fins inside the manhole containing polyethylene sheets inclined at 8° to the horizontal is required.
The base of the manhole consists of a polyethylene sheet of a suitable thickness welded to the inside wall of the manhole.
In the case of custom-made manholes, no restrictions are imposed on the diameter of inlet/outlet pipes and manholes of any type may be constructed according to designer’s requirements (e.g. L-shaped manholes, jump manholes, or manholes with multiple inlets).
Ends of manholes with ND/OD 800 – 1000 – 1200 risers can be created using a PEMD conical reduction adaptor, obtained by 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 ND/OD 1000 – 1200 risers.