Bang Pakong Combined Cycle (Unit l-2 Replacement) Project Technical Document The others wall system such as diaphragm wall or pneumatic caisson may be used for pump pit subjected to EGAT approval. Cooling water intake pumphouse shall be designed for three (3) similar sets of pumping system servicing 3 blocks of power plant. Adequate working area required for common laydown area and installation of three (3) sets of pumping system shall be provided for effective operation and maintenance. Arrangement of pumping system shall be as shown in DWG. BPRP1-C-O15. For this project, only one (1) set of pumping equipment system shall be installed. Pump operating floor shall be reinforced concrete slab with floor hardener. Pump floor elevation shall be at least 1.0 m higher than the maximum flood water level. A convenient access road and bridges from pumphouse to the reservoir shall be provided. Pump pit shall be underground reinforced concrete structure. The size of pump pit shall be designed and constructed for three (3) sets of pumping system suppoiting three (3) blocks of power plant. For this project, only one (1) set of pump pit will be used. The Contractor shall provide temporary closure for the other two (2) sets of pump pit which will be used in the future. Temporary closure shall be conveniently removed in the fixture. Minimum clearance size of pump pit shall conform to pump design requirement, effective operation, sufficient maintenance and accessible space. The reinforced concrete baffle wall and flow screen system shall be provided for each pump. The minimum clearance between equipment and the nearest wall shall not be less than 1.0 m. Valve chamber shall be underground reinforced concrete structure with precast concrete cover. Steel cover shall also be provided for maintenance access. The top of valve chamber wall shall be at least 1.0 m higher than the maximum flood water level. Suitable sump and drainage system shall be provided. The valve chamber pit shall be designed to provide adequate area for installation and maintenance of butterfly valve with motor drive as well as sump with drainage system. Access from ground to bottom of pump pit and valve chamber shall be provided through stainless steel ladder equipped with stainless steel handrail. The system shall be designed and constructed to accommodate any consequences of future differential settlement between the approach channel, the reservoir, the manhole chambers, the inlet pipelines and the cooling water intake pumphouse. The size of element and amount of reinforcement shall be selected on the basis of the requirement of stress limit and sen/iceability crack-width limit to achieve the required service life. 1 Volume 2 Page 2A—27