More Information on Underground Sewer Manhole Bases
Combining flexibility with ease of installation, the Inspection Chamber Assembly includes 50kN lid, 300mm riser, 450mm dia chamber base and frame rings and chamber reducer. Providing more on site solutions the 450mm Chamber Base alternatives are available with branch sockets designed to optimise flow management, for drainage layouts and 110mm. The assembly meets the requirements of Building Regulations Part H1.
Inspection chambers may be utilised as an alternative to traditionally constructed manholes for reverse depths of up to 1.2 metres. By cutting a riser, between the ribbed sections, to the height with a fine tooth saw can easily accommodates intermediate depths
Chambers should be installed onto a base of suitable material and care ought to be taken to guarantee the bedding material is evenly compacted under the foundation so the room is fully supported. Sidefill material should extend to just below ground level and the cast iron cover and frame set in a concrete plinth.
Two sizes of manhole bases are available, one has 110mm inlets and outlets and the other has 110/160mm inlets and 160mm outlet. Both have ring seal socket connections. Jointing riser to riser, or when joining 320mm or 450mm manhole bases to a riser, the ring seal is found as opposite, in the groove. To help ease jointing it is recommended that silicone lubricant is used.
When installing a manhole base that's more than 1.2m deep the entry to the manhole base must be reduced to 320mm to prevent human entry. Inspection and maintenance should be carried out by remotely operated equipment and the maximum depth is restricted to 4m. Human entry is only allowed when there is no other alternative.
For full details please refer to the Building Regulations (England & Wales) Approved Document H – Drainage & Waste Disposal – April 2002 or Part 3 of the Building (Scotland) Regulations 2004 BSEN 752