Construction of Giresun Wastewater Treatment Plant  Tender Dossier Volume 3 Employer’s Requirements Section 09: Building Works  21 of 24 9.2.12 Inspection, storage and connections  9.2.13 Cold water pipes and valves  ends. The length of the cast-in pipe including sockets shall be according to the thickness of the wall.  No piping shall be laid parallel to footings or outside bearing walls closer than 1 meter. Water service  pipes, or any underground water pipes shall not be run or laid in the same trench as the sewer lines.  Drainage pipes can be allowed to discharge at a height of 450 mm maximum above the bottom of a  manhole. If the vertical drop in the manhole should exceed 450 mm, a drop manhole shall be used.  Where it is required to cut rigid pipes it shall be done by a suitable pipe cutter so as to leave a clean  and square end to the axis of the pipe.  Vent pipes shall extend through the roof and terminate at an efficient height and as may be agreed by  the Engineer. The vent pipe passengers through roofs shall be made watertight and shall be provided  with a PVC de-aeration caps on the roof. Where necessary, PVC-gratings shall be provided at the ceil- ings.  All pipes shall be thoroughly inspected prior to laying and any suspected cracks or damaged material  shall be rejected. The pipes shall be stacked horizontally during storage and the sockets must be pre- vented from resting on the ground. All connections shall be made watertight and gastight. Where vent  pipes connect to a horizontal soil or waste pipe the vent shall be taken off above the centre-line of the  pipe, and the vent pipe shall rise vertically.  No work of breaking into an existing public sewer and forming a connection shall be carried out with- out prior approval of the Engineer.  If any bedding or protection is removed to make a connection to a sewer or drain, the damage shall be  made good.  Connections to sewers shall be made at existing manholes.  The Contractor shall obtain the Engineer’s approval to his proposal for the potable water distribution  system on the site.  Cold water distribution pipes shall be HDPE PE100, PN 16 for the main service pipes connecting to  the city water meter. All precautions shall be taken to protect water supply and distribution pipes  against contamination from the sanitary system.  Underground water service pipes and sewer lines shall be not less than 1 meter horizontally and shall  be separated by undisturbed or compacted earth when they cross each other. Concealed pipes shall be  installed in such a way as to permit easy access for maintenance. This applies particularly to valve lo- cations.  All valves shall be fixed in neatly arranged vertical lines, and adequately pitched horizontal lines to  allow the system to be properly vented and drained. Air pockets, traps and sags shall be carefully  avoided. Pipes shall not be welded.  Gate valves shall be provided on all main and branch pipes for isolating sections of piping for mainte- nance. Each sanitary fixture shall be provided with a stop valve for washer replacement. The stop  valve shall match the trim provided with the fixture.  9_Vol3_d4.3_Section 9 building works_en_GIR_rev6.docx 