More Information on Brett Martin Manhole Bases:
Combining flexibility the Inspection Chamber Assembly includes sealing rings, 300mm riser lid and frame, 450mm diameter base and chamber reducer. More Chamber Base alternatives are available with branch outlets designed to optimise flow direction, for 110mm and 160mm drainage layouts. The assembly meets the requirements of Building Regulations Part H1. For more information download the Access and Inspection Chambers brochure and the 450mm Lids and Frames leaflet.
Brett Martin have developed a range of underground drainage systems and inspection chambers for Adoption 7 (SfA7) and Construction Regulations. At Brett Martin our drainage solutions are designed and developed to achieve compliance with industry regulations and standards. This ensures that our full offering of Access and Inspection Chambers satisfy the requirements set out in the criteria for all adoptable drainage networks -- including manholes.
The manhole base chamber assmebly includes products for both 110mm and 160mm drainage outlets.
Polypropylene (PP) Inspection Chambers have a diameter of 280-550mm and cost much less than their concrete counterparts. Raising bits (risers) are utilised to cope with deeper drains up to a maximum of 1 metre; anything more profound than 1000mm needs a brick-built or concrete section manhole. The 450mm manhole bases have 5 inlets and one outlet; fresh inlets are stoppered to prevent ingress of soil. The base unit ought to be placed on a 100mm thick bed of concrete and the lifting pieces checked for plumb (verticality) prior to backfilling. If placed inside a driveway or other trafficked area, they ought to be surrounded with 150mm of concrete all around to avoid deformation, and a heavy duty cover utilised. The manhole base chamber, or lifting pieces, can easily be cut with a saw to accommodate the framework for the cover at the right level.