AS 4809:2017 Copper pipe and fittings- Installation and commissioning
6.2.2.7 Silver brazing
A silver brazing alloy, as specified in Clause 4.3.4, may be used to join copper pipes and fittings. A compatible flux shall be used when making joints with copper alloy fittings.
6.2.2.8 Pipe bending
Bendable and annealed temper tube, in accordance with AS 1 432, may be bent provided the following requirements are met:
(a) Specialized equipment shall be used to form bends in copper pipe.
(b)‘Hard drawn’ temper pipe shall be annealed prior to bending.
(c) The minimum centre-line radius for bending annealed temper copper pipe to a 90° bend shall be at least three times the outside diameter of the pipe.
NOTE: Bendable temper copper pipe has sufficient ductilty to enable a 90° bend with minimum centre-line radii of 45 mm, 60 mm and 85 mm for nominal sizes DN 15, DN 18 and DN 20 respectively, without local annealing.
(d) Pipes shall be free of physical damage that reduces the wall thickness by more than 10% of the minimum thickness.
(e) Wrinkling shall not exceed 1 mm. This shall be measured between adjacent trough and crest at the midpoint of the bend.
(f) Flattening of the pipe during bending shall not reduce the outside diameter in any one plane by more than 10% of the minimum mean diameter.
6.2.3 Insulation and protection Insulation shall be placed around copper pipe where it is necessary to-
(a) provide protection against water freezing;
(b) reduce heat loss from the water within the pipe;
(c) protect against mechanical damage to the pipe;
(d) protect the pipe from aggressive environments such as acidic soils;
(e) reduce heat gain;
(f) comply with environmental issues stipulated in building codes; or
(g) protect when enclosed in concrete. Insulation materials, and in particular porous materials such as natural products like wool, should only be used where moisture can be prevented from reaching the insulation.
NOTE: Waterlogging of insulation material will reduce the thermal efficiency and may contribute to external corrosion. The thickness of the insulation required is dependent on the material used and the degree of protection required.
The minimum thickness of insulation required to prevent freezing shall be in accordance with AS/NZS 3500.1. If weather conditions are particularly severe, the presence of insulation may not prevent water in the pipe from freezing. Where a building is unattended during winter months the pipework should be completely drained to prevent damage from water freezing.