These are used for the inspection and maintenance of sewage piping. Manholes are made with a flowing channel to provide a steady flow of refuse liquids. The recommended size for the flowing channel is 1/3 – ½ from the diameter of the main line. This means that there is a channel at the base of the manhole to ensure the better flow of refuse liquids.

NB! If possible, please avoid using square angle turns in the flow channel. To prevent a turn with a square angle we recommend the use of a manhole body with a suitable diameter into which a gently sloping flow channel can be built.