In the last few decades, polyethylene has been used as the most suitable material for manholes due to its favorable properties. The properties of the polyethylene manholes discussed below have led to an upward trend in their use, so that more than 80% of manholes currently used in recent projects in Europe are of these types.
TYPES OF MANHOLES
For inlets up to 600 mm, direct-passage polyethylene manhole with diameter 1000 mm is used. For sizes of 800 mm and sometimes 1000 mm, shafts of 1200 mm and 1400 mm are also used. But it’s better for size 1000 mm or bigger one to use a side-passage manhole.
To increase the speed of flow and better use of existing space, for larger pipe sizes, in the main route of the pipes, manholes are tangentially mounted on the main pipe, which in comparison with other manholes, is faster and takes less space.