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Drainage & Piped Services Standard Specification
Version 2014-1
Third party certification: BSI Kitemark.
Concrete: Submit proposals.
Aggregate size (maximum): Submit proposals.
Execution
Installing precast concrete shallow access chambers for below ground drainage type B
Standards: To BS EN 752, and in accordance with relevant parts of the National Annex (NA) and In
accordance with relevant parts of Sewers for Scotland. 2nd edition.
Base slab thickness: Submit proposals.
Chamber dimensions:
Size (nominal internal): Submit proposals.
Depth (cover level to pipeline invert): As manhole schedule.
Concrete surround: 150 mm thick.
Backfilling:
Laying fill: Submit proposals.
Compaction: By hand in 100 mm layers.
Jointing precast concrete below ground drainage access chamber sections type B
Inner joint surface: Trim surplus jointing material extruded into chamber and point neatly.
Laying conventional channels, branches and benching in access chambers for below ground drainage type
A
Main channel: Bed solid in 1:3 cement: sand mortar.
Branches:
General: Connect to channel, preferably at half pipe level, so that discharge flows smoothly
in direction of main flow.
Branches greater than nominal size 150 mm: Connect the branch soffit level with the main
drain soffit.
Connecting angles more than 45° to direction of flow: Use three-quarter section channel
bends.
Benching:
Profile: Rise vertically from top of main channel to a level not lower than soffit of outlet pipe,
then slope upwards at 10% to walls.
Topping: Monolithic with benching, and with dense smooth uniform finish.
Application: Before benching concrete has set.
Laying preformed plastics channels, branches and benching in access chambers for below ground
drainage type B
Main channel: Bed solid in 1:3 cement: sand mortar.
Branches:
General: Connect to channel, preferably at half pipe level, so that discharge flows smoothly
in direction of main flow.
Connecting angles more than 45° to direction of flow: Use three-quarter section channel
bends.
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McDonalds Restaurants Ltd
