【法规名称】
【法规编号】 79817 什么是编号？
【正 文】
第11页 CAP 102A WATERWORKS REGULATIONS
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[接上页] 4. (1) Ball valves of the "Piston" type and of a nominal size not exceeding 50 mm shall comply with BS 1212, Part 1 for ball valves and shall comply with the following requirements- (a) valves shall be provided with a washer of suitable vulcanized rubber or some other equally suitable material and the washer shall be enclosed in an internally flanged cap screwed to the piston; (b) the body and piston shall be of a corrosion-resisting alloy, and the lever shall be of a corrosion-resisting alloy or of copper and shall be of sufficient rigidity not to bend permanently under working conditions. (L.N. 320 of 1992)(2) Ball valves not being of the "Piston" type shall be sound and suitable and comply with the following requirements- (a) high pressure valves shall close against a test pressure of 1400 kPa, medium pressure valves against a test pressure of 700 kPa, low pressure valves against a test pressure of 300 kPa; and the valves, not being valves having an interchangeable orifice seating, shall have the letters "H.P.", "M.P." or "L.P." respectively cast or stamped on the body of the fitting, and shall, while held in a closed position, be capable of resisting a pressure of 2000 kPa; (b)-(c) (Repealed L.N. 320 of 1992) (d) valves of ferrous metal of a nominal size exceeding 50 mm shall be provided with a flange on their inlets complying with BS 4504, Part 1, Table 16, shall be protected against corrosion by dipping in accordance with the requirements of BS 4164 or by galvanizing in accordance with the requirements of BS 1387 and shall have all their working surfaces lined or faced with, and its orifice seating of, a corrosion-resisting alloy.(3) Ball valve floats of a nominal outside diameter not exceeding 300 mm shall comply with BS 1968 for copper floats or with BS 2456 for plastic floats. (4) Ball valves when fixed to a cistern shall have the size of the orifice, the size of the float and the length of the lever so proportioned to one another that, when the float is immersed to an extent not exceeding half its volume, the ball valves shall be watertight against the highest pressure at which it may be required to work. 5. Ball valves or float-operated valves fitted to storage cisterns shall be securely and rigidly fixed thereto above the water-line, and shall be supported independently of the inlet pipe (unless such inlet pipe is itself rigid and rigidly fixed to the cistern), in such a position that no part of the body of the valve will be submerged when the cistern is charged to overflowing level. 6. Where a ball valve or float-operated valve provided with a pipe so arranged as to discharge water into a cistern below its overflowing level, an air hole shall be provided in the outlet chamber of the valve above such level of a size sufficient to prevent siphonage of water back through the valve. 7. No ball valve shall be fitted to a storage cistern to contain heated water. 8. Gate valves shall comply with BS 5154 for copper alloy gate valves for general purposes. 9. Fitting with threaded outlets, or any device facilitating the connecting of rubber or other type flexible hose, shall not be permitted, except with the written permission of the Water Authority. 10. Draw-off taps, valves and valve floats for use with salt water shall, where applicable, comply with the British Standard and other requirements for such fittings for use with fresh water and shall, in addition, be manufactured from materials capable of withstanding the corrosive effect of salt water. 11. No draw-off tap or valve shall be installed or used unless it has been tested in accordance with regulation 21 or otherwise approved by the Water Authority. (L.N. 320 of 1992) (L.N. 252 of 1977) PART III COLD WATER STORAGE CISTERNS 1. No cistern for the storage of cold water shall be installed or used except with the permission in writing of the Water Authority who shall specify the maximum permitted capacity. 2. Every cistern shall be watertight, of adequate strength, properly supported and shall be constructed of concrete, galvanized mild steel or other approved material. (L.N. 320 of 1992) 3. A cistern of mild steel not exceeding 5000 litres capacity shall comply with BS 417, Part 2 for galvanized mild steel cisterns. 4. (a) Every cistern shall be located so as to minimize the risk of contamination of the stored water and shall be fitted with suitable close fitting lockable covers which shall not be air-tight. Covers shall be positioned so as to facilitate inspection and cleaning. (b) Where a storage cistern for non-potable water is placed adjoining to a storage cistern for potable water there shall be an air space between such storage cisterns. 5. Cisterns shall be fitted with a ball valve controlled inlet in the case of a gravity supply or with an automatic control switch in the case of a pumped supply. The ball valve or control switch shall shut off the supply when the water level is 25 mm below the invert of the overflow pipe. The invert 25 mm above of the inlet pipe or the face of the outlet nose of the ball valve shall be not less the top of the overflow pipe. |
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