Water Proofing System Sample Clauses

Water Proofing System. Sheet waterproofing membrane systems for the tunnel shall comprise of a geotextile fleece fixed to the primary lining substrate in combination with a sheet waterproofing membrane fastened to this. Waterproofing shall be applied to crown and sidewalls above footing or invert arch level. The waterproofing membrane shall always be located between shotcrete support and final concrete lining. As the underground structures referred to be not immersed below a distinct groundwater table no membrane waterproofing will be provided for tunnel inverts. The design life of the water proofing membrane shall be minimum 100 years. Where the waterproofing system is to be divided into sectors, the water stops should be formed of material that can be welded to the sheet waterproofing membrane. Additional drainage capacity shall be provided in case of water inflows in agreement with the Employer’s Representative by studded drainage membrane made from thermoplastic material (dimpled sheet) attached prior to installation of the geotextile fleece or equivalent drainage layer approved by the Employer’s Representative. Waterproof membranes shall not be stored in direct sunlight prior to use. Waterproof membranes shall be protected from damage at all times especially during installation of reinforcement. The water proofing membrane shall have a signal layer to indicate damages due to handling and installation of reinforcement. The integrity of the signal layer shall be checked prior to concreting of final lining. - The amount of membrane stored in the tunnel shall not exceed two working day’s production to minimize the fire load stored underground. - The installation length of the water proofing system in advance of the final lining shall not exceed 300 m, unless special measures are considered in agreement with the Employer’s Representative. The waterproof membrane shall consist of a continuous impermeable heat-welded sheet of one of the following materials: - soft polyvinyl chloride (PVC) unreinforced - flexible polyolefin (FPO/TPO) unreinforced The membrane as supplied shall be of such dimensions and shape as will result in the minimum of on-site seam welds. The installation of recycled membranes and/or membranes including DEHP (DOP) plasticizer is not permitted. 1.1 Site Information General