AS NZS 4793:2009 pdf free download – Mechanical tapping bands for waterworks purposes
.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.
The purpose of product certification is to provide independent assurance of the claim by the manufacturer that products comply with the Standard(s). The certification scheme should meet the criteria described in HB 18.28 (ISO/IEC Guide 28) in that, as well as full type testing from independently sampled production and subsequent verification of conformance, it requires the manufacturer to maintain effective planning to control production. The certification scheme serves to indicate that the products consistently conform to the requirements of the Standard(s). Product certification shall be conducted by a certification body accredited by the Joint Accreditation System for Australia and New Zealand (JAS-ANZ) or by another certification body that is acceptable to JAS-ANZ. The frequency of the sampling and testing plan as detailed in Paragraph A3 shall be used by the certifying body for product compliance auditing. However, where the manufacturer can demonstrate adequate process control to the certifying body, the frequency of sampling and testing nominated in the manufacturer’s quality plan and documented procedures, shall take precedence for the purpose of product certification.