Specifications Part 1 - Water Supply, Sewerage and Tube Well Works

6.2.9.6 The valves should be tightly closed when being installed, as this keeps thevalves rigid and prevents any foreign matter from getting in between theworking parts of the valves.6.2.9.7 While installing flanged valves, each flange bolt should be tightened a little at atime, taking care to tighten diametrically opposite bolts alternately. The practiceof fully tightening the bolts one after the other is highly undesirable.6.2.9.8 After installation of the valve, the valve and the pipe line should be flushed withwater to remove any foreign matter that may be present in them.6.2.9.9 If any leak is detected at the valve seats, applying extra torque on the valvespindle to set right the valve is not good practice, the valve seats should beexamined and, if necessary, repaired by scraping or replacing wherenecessary.6.2.9.10 Valves in exposed positions should be protected in cold weather where there isa likelihood of their becoming frozen and bursting.6.2.9.11 Surface boxes conforming to IS: 3950-1966 should be provided to cover thevalve chamber for the safety and easy identification of the valves.6.2.9.12 The direction of opening and closing should be clearly indicated.6.2.9.13 Suitable identification plate should be provided as near to the actual location ofvalves as possible.6.2.9.14 Care should be taken to ensure that the joining material sits squarely betweenthe flanges of the valve and pipe lines or tails without obstructing the waterway. It is to be ensured that there are no kinks in the joints material as mightallowed leakage in service.6.2.9.15 Maintenance of sluice valve should be done periodically as per guide line in IS2685:1971 chapter 4.6. 3 Air Valve6.3.1 Air valves are to be used for evacuation of accumulation of air in water mainsunder pressure, for the exhaust of air when such mains are being charged withwater and for inlet of air when they are emptied of water.6.3.2 There are two types of air valves generally use. Single air valves with singleball and double air valve with double ball. The single ball type can have eitherlarge orifice or small orifice, the former being only suitable for emptying andfilling of pipe line and latter for discharging small quantities of entrained air inthe pipe.6.3.3 Double air valves are commonly available which are suitable for dual purposewith a large orifice and a small orifice in one unit, with a common connectionUrban Administration & Development Department Page 67