Manhole

The important parts of a manhole is the access shaft, working chamber and cover. Manhole may be either of shallow depth (75-90 cm), normal up to 150 cm or deep more than 150 cm. Access shaft. The portion of hole starting from the cover and going down to the full depth is access shaft. The height of access shaft is 0.9 to 1.5m. Working chamber. The lower portion of manhole with vertical wall is called working chamber. Steps or Ladder. Steps are provided for a man to enter in and check the fault if any. It may be either mobile ladder or installed permanently in the access shaft. Foundation. Bottom of manhole is made of concrete and is called invert. It is sloping towards the channel which is a part of sewer. Cover. Manhole is provided with a frame on the top which is firmly embedded in pavement. The cover of the manhole should be strong enough to withstand the loads of traffic.