Bang Pakong Combined Cycle (Unit 1-2 Replacement) Project Technical Document Hardstanding or heavy-duty reinforced concrete pavement designed and constructed to withstand minimum axle load of 120 kN (12 tons) or any greater axle and expected wheel load shall be provided for the unloading bays of the Generation Building, chemical unloading station and other areas as required. The areas shall be sufficient for their intended use, function, and the maneuverability and capacity of the vehicles using the hardstanding. Drainage System The Contractor shall design a pennanent storm water drainage system to comply with Section 1B.3.11, Volume 2. The Contractor shall design the storm water drainage system for the boundary area so that storm water can be rapidly discharged to the specified tenninal points as shown on DWG. Nos. BPRP1-C-011 and BPRPI-C-012. The drainage system shall be designed and constructed to prevent water penetration into underground soil layer and undemeath the buildings and structures. Except noted otherwise, storm water drainage shall be nomially designed as open or underground drains and rainfall intensity 160 mm/hr shall be used in design. The main drains shall be kept outside of the buildings and shall follow the main roads within the boundary limits. Storm water runoff shall be collected by arterial drains which shall converge towards the main drains. All drains shall be designed at a gradient giving adequate velocity for self-cleaning flow. The invert of manholes and outgoing drains shall not accumulate water at any time. The distance between each manhole shall not be more than 10 meter center to center. As shown in Drawing No. BPRP1-C-011, the storm water from main plant area (Area 1) shall be drained to terminal point TP-C1 where the Oil Water Separator system shall be p1'ovided.The Contractor shall also construct new storm drainage system connecting from terminal point TTP-ClA to TP-ClB. At point where new storm drainage system crosses the existing road, concrete box culvert capable of supporting traffic vehicle shall be provided. Size of box culvert shall also be determined based on drainage capacity which shall be equivalent to the capacity of existing drainage system at terminal point TP-ClB. From TP-C2 to TP-C3, the reconstructed drains shall be reinforced concrete rectangular gutter with 2.50 m width. From TP-C4 to TP-C5, automatic pumps shall be installed at tenriinal point TP-C4 and steel drainage pipe shall be installed connecting from automatic pump at tenninal point TP-C4 to tenninal point TP-C5 in order to divert existing storm Water drainage. Pump capacity and pipe diameter shall be equivalent to capacity of the existing one which will be demolished and replaced. The new route of reconstructed gutters shall be separated and shall not affect the existing drainage system. The steel grating with truck load shall be provided for drains at road crossing and road sides. Manholes shall be provided at all changes in direction or gradient of the pipeline. Manholes shall be provided with heavy-duty manhole covers where they are in the vicinity Volume 2 Page 2A-32