General Requirements for Valves. Valves shall be manufactured and installed in accordance with internationally recognized standards / Indian Standards. In-line valves shall be double flanged with the faces parallel to each other and at right angles to the valve centerline. Backside of valve flanges shall be machined or spot faced for proper seating of the head and nut. Valves to be buried or installed in underground xxxxxxxx, where access to a hand wheel would be impractical, shall be operated by means of an extension spindle and/or keys. Valves shall be suitable for frequent operation as well as operation after long periods of idleness in either the open or closed position. All the valves shall be manually operated. For butterfly valves the gearbox shall be provided with self- locking devices. A locking facility shall be provided for the valve in either the fully open, fully closed or intermediate position. Gate (sluice) valves and butterfly valves shall be provided with position indicators, to show whether the valve is in the open, closed or an intermediate position. Sluice and Scour valves shall be provided with an extension spindle for operation from operating level / ground level.
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Samples: gmdwsb.assam.gov.in, gmdwsb.assam.gov.in, gmdwsb.assam.gov.in
