AS NZS 4793:2009 pdf free download

AS NZS 4793:2009 pdf free download
AS NZS 4793:2009 pdf free download.Mechanical tapping bands for waterworks purposes
4.1.6 Resistance to rotation, longitudinal sliding and depressurization
When tested in accordance with Appendix D, tapping bands designated for use on plastics pipes shall not—
(a) show any signs of leakage;
(b) rotate on the pipe as a result of the applied moment;
(c) slide on the pipe as a result of the applied force; or
(d) fail in any other manner.
4.2 BI-METALLIC COUPLE
When a metallic tapping band intended for use with metallic watermains is tested as follows, the electrical resistance between the tapping band and the ductile iron test pipe shall be not less than 50 000 Ω:
(a) Assemble the tapping band centrally on a length of clean ductile iron pipe or other metallic pipe approximately 100 mm longer than the tapping band with an outside diameter compatible with the nominal diameter of the tapping band.
(b) Abrade a small area on the pipe and the tapping band not less than 25 mm from the contact surfaces to provide clean contact points.
(c) Place the assembly on an electrically insulated surface.
(d) Measure the resistance between the abraded areas of the tapping band and the pipe with an insulation resistance tester with a driving voltage of not less than 500 V.
4.3.1 Hydraulic performance
For integrated valve and outlet assemblies, the manufacturer shall declare the maximum head loss, at velocities of 0.5 m/s and 1.25 m/s, for each size of tapping band, when tested in accordance with Appendix A of WRc WIS 4-22-02. The installation shall be on ductile iron pipe, using an integrated property connection ball valve complying with AS 4796 with a 1 m length of Type B copper pipe of the same nominal size as the threaded outlet. NOTE: WRc WIS 4-22-02 is available as a free download from www.wis-ign.org.
4.3.2 Assessment of cutter efficiency
Where tapping bands incorporate an integral cutter, the cutter shall be tested for efficiency. A batch of 25 such fittings for each distribution main material shall show 100% success in cutting a clean hole and securely retaining the cut coupon within the cutter. The range of distribution main diameters and wall thicknesses shall be represented in the tests.