SECTION B - Derry City Council

APPENDIX 5/1: DRAINAGE REQUIREMENTS
1 Layout of drainage of amenities and roads shall be constructed as shown on contract drawings.
The connection of new drainage systems to the existing combined drainage system to be agreed
on site, with Project Manager.
2 Drainage gullies and chambers shall be constructed and detailed as shown on the contract
drawings.
3 The bedding detail to foul and storm drainage is to be Type S as shown on Drawing No. F1,
MCDHW, Volume 3, “Highway Construction Details”. All bedding materials to SHW Clause 503.3.
Where the drain crosses under a carriageway, the backfill above the pipe bedding is to be well
compacted Type 3 material, and comply with any other requirements set down by DRD Roads
Service, or with C20/20 mass concrete as indicated on Drawing No. 073030/GA/35, pending on the
depth of cover to the crown of the pipe.
4 The bedding detail to filter drains to be Type L as shown on Drawing No. F2, MCDHW, Volume 3,
“Highway Construction Details”. All filter material to be Type A. Were the filter drain crosses under a
carriageway, the filter materials are to be substituted by well compacted Type 3 material.
5 Joints to surface water and foul drains shall be watertight. Ridged joints shall not be used.
6 Chamber sizes are indicated on the contract drawings and all in accordance with Standard
Drawings Section 1, Series F of Volume 3 of the Manual for Contracts Documents for Highway
Works.
7 Gully gratings and frames shall be ductile iron to BS EN 124 Group 3.
8 Saddles may be used for gully connections to the filter drains to Cause 508.7.
9 All new road gully chambers shall be trapped, and shall comply with Highway Construction Detail
Drawing No. F13 and Clause 508 of the Specification.
10 Drainage to Structures
The drainage to be provided behind the new contractor designed gabion walls, reinforced earth
walls and crib walls will form part of the contractor’s design but should not comprise less than a 150
mm diameter (minimum) uPVC rigid walled perforated pipes.
11 Testing and cleaning of all foul and storm water drains to comply with clause 509 and as described
listed in Appendix 1/5. Chambers on the foul and storm drainage shall be tested for water-tightness.
All carriers, foul, storm drains to be surveyed by CCTV and copy of survey to be forwarded the
Project manager for approval, before the drainage is brought into use
192