Construction of Giresun Wastewater Treatment Plant  Tender Dossier Volume 3 Employer’s Requirements  Section 05: Earth Works, Pipe Works and Ground Improvement  23 of 49 5.3.9 Pipe Installation  5.3.9.1 General  5.3.9.2 Tolerances  5.3.9.3 Excavation for Pipes in Trenches Installation of pipelines includes supply, laying and jointing of pipes and fittings, construction of bed- dings and foundations, manholes and other structures in the line, testing, and commissioning.  Pipes shall be laid in accordance with:   Gravitation pipes (TS EN 1610) and   Pressure pipes (prEN 805).  All plant, operation and haulage required from source or store to bring the pipes, valves, etc., to their  place of laying of fixing, including any unloading into temporary storage areas and any subsequent  reloading for haulage to the place of laying shall be included in the supply of pipes and fittings.  Pipe works shall not begin unless the whole trench between two manholes has been excavated.  During installation pipes are to be suitable anchored to prevent flotation while backfilling.  All pipes shall be laid accurately and handled in accordance with the Manufacturer's instructions. The  pipes shall be laid into the trench on the bedding material and joints made. During installation careful  checking and supervision shall ensure that the pipes are laid to the correct line and grade, and sealed at  each joint, fitting, branch and manhole. The level of the grading and the pipe shall be checked with a  laser.  Pipes shall be laid accurately to the lines and levels shown in the design. The maximum permitted de- viation from the specified line and level for pipelines shall be:   Up to 600 mm: 10 mm   Greater than 600 mm: 15 mm.  However, negative gradients are not accepted.  (supplementing the text under "Earthworks")  Whether trenches for pipe lines are constructed with vertical, sloping, or stepped sides, that portion of  the trench which extends from the foundation level to not less than 300 mm above the crown of the  pipe when laid in its correct position, shall unless otherwise specified, or ordered by Engineer, be  formed with vertical sides up to 1.5 m above the foundation level at the minimum practical distance  apart.  The minimum trench width shall follow requirements as stated in TS EN 1610, table 1. If the trench  depth exceeds more than 1.5 meters a trench box system shall be used or the trench shall be protected  by other means e.g. by shoring or sheet piling, etc. approved by the Engineer.  Pipe trenches shall be kept free of surface or ground water. For areas with high ground water level  shall be reduced using “Well-Point method”. If mentioned method cannot be applied, stainless steel  sheet piles shall be used.  No excavations with battered sides shall be made in roads, footpaths or within 10 m of any existing or  proposed building or other structure.  The material excavated from the trenches shall be handled with care, with asphalt, stone blocks, rock  and stone from road construction or broken out of the trench during excavation, stock piled separately  from the granular material of the natural ground.  5_Vol3_d4.3_Section 5 Earth and pipe works_en_GIR_rev6.docx 