AS 4795:2002 pdf free.Double-flanged butterfly valves for waterworks purposes.
2.1 GENERAL
The basic materials that shall be used for the manufacture of the valve components are listed in Table 2.1. The materials listed are the minimum acceptable standard materials.
Alternative materials may be used, provided they are equivalent in performance, particularly with respect to strength. corrosion-resistance, valve operation and durability. The alternative materials used shall comply with the requirements listed in Appendix D.
Non-metallic materials used in the componentry of valves shall be fit for the intended purpose and shall exhibit dimensional stability after extended periods of time immersed in water and wastewater.
NOTE: Material equivalence will be considered by a ruling committee of purchasers and suppliers selected by the Water Services Association of Australia (WSAA) from standing members of Committee WS-022.
2.2 CORROSION-RESISTANT MATERIALS
For the purposes of this specification, the following materials are deemed to be corrosion- resistant:
(a) Copper alloys complying with AS 1565, AS/NZS 1567 or AS/NZS 1568 and complying with AS 2345.
(b) Austenitic stainless steel complying with ASTM A276, series 300, containing not less than 8% nickel, except that Grade 303 is not permitted, and duplex (ferriticaustenitic) stainless steels UNS S32750, S32304, S3 1 803 and S3 I 500.
(c) Stainless steel complying with ASTM A3l3.
(d) Phosphor bronze complying with AS 2738 Alloy 51 8.
(e) Nickel-copper-iron alloys complying with AS 2738.2 Alloy 713 or ASTM B 127, ASTM B 163, ASTM B164 and ASTM B 165.
(0 Copper nickel alloy complying with AS 2738 Alloy 706 or Alloy 715.
Other materials may be considered based on published corrosion resistance data.
2.3 CONTAMINATION OF WATER
Components in contact with drinking water shall comply with AS/NZS 4020.
A scaling factor of 0.01 shall be applied except for the microbiological growth test where a
factor of 0.33 shall be applied.
2.4 0-RINGS (ELASTOMERIC TOROIDAL SEALING RINGS)
0-rings shall be manufactured from an elastorneric material that is not injuriously affected by the fluid, temperature or environmental conditions to which the 0-rings will be subjected in service. 0-rings shall comply with AS 1646.1 and AS 1646.2 or AS 1646.3. The hardness of the moulded-rubber material shall be in the range 71 to 80 when tested in accordance with AS 1683.15.1 using ‘Standard’ specimens.AS 4795 pdf download.