Common use of Materials of Construction Clause in Contracts

Materials of Construction. The materials of construction for butterfly valves shall be in accordance with Table 5-2. Item PN 1.6 Rated Valves PN 1.0 Rated Valves Body SGI IS 1865 Grade 500/7 CI IS 000 Xxxxx XX 000 Xxxx XXX IS 1865 Grade 500/7 CI IS 210 Grade FG 260 Shaft Stainless Steel BS 970, Grade 431 S29 Stainless Steel BS 970, Grade 431 S29 Body and Disc Seat Stainless Steel AISI 316 Stainless Steel AISI 316 Bearing Steel backed PTFE (Teflon) Steel backed PTFE (Teflon) Internal Fasteners Stainless Steel SS316 Stainless steel SS316 The butterfly valves can alternatively be supplied in fabricated steel with material components of Body and Disc confirming to IS 2062 Gr. B / IS 2002. A minimum corrosion allowance of 3 mm shall be added. Butterfly valves conforming to IS 13095 will also be accepted. Gearboxes shall be of the self-locking type, with a continuous indicator. Traveling nut and screw type of gearboxes shall not be acceptable. Each gearbox must conform to the provisions of AWWA C504. The rated torque capability of each operator shall be sufficient to seat, unseat and rigidly hold in any intermediate position the valve disc it controls under the operating conditions specified. Operating torque must be as per requirements given in AWWA C504. The operator shall be of worm and worm wheel design, self-locking type with or without an additional spur gear arrangement to ensure that the effort on the hand wheel is limited to the pull specified. All valve operators shall be equipped with adjustable mechanical stop-limiting devices to prevent over- travel of the valve disc in the open and closed positions. Either end of the worm shaft must be provided with a needle roller bearing to take the lateral thrust. The housing for the gearing must be enclosed and sealed in such a way that there is no leakage of oil / grease even after long period of idleness and there shall be no ingress of rainwater. Operator for valves, which are likely to be submerged in water for any period of time, shall be watertight. The hand wheel may be provided with an extension for easy grip. The hand wheels must have a provision for locking with a chain and pad lock. All operators when fitted to the valve shaft shall ensure clockwise closing and this shall be indicated on the housing. A mechanical indicator is to be provided to show disc position and end of travel. Sluice valve shall generally conform to BS: 5150 / IS 14846. They shall be of non-rising spindle type. The gate face rings shall be securely pegged over the full circumference of the valve. Valves shall have two positions marked at the closed end of the scale. The first position corresponding to the position of the gate tangential to the bore of the seating and the second position below the first, corresponding to the position of the gate as it sits on the seat after moving a further distance equal to the depth of the seating. Valves in buried service or in vaults shall be furnished with extension spindles. Each extension spindle shall be furnished with a universal coupling and intermediate supports. Pressure rating for the sluice valves to be installed in the distribution network shall be as specified in Table 5-3. Table 5-3 Pressure Ratings for Sluice Valves Service Pressure Rating Operating Pressure (MPa) Body Test Pressure (MPa) Distribution Lines PN 1.6 1.6 2.4