This standard sets out minimum safety requirements and makes recommendations for the design, fabrication, installation, inspection, testing, operation and maintenance of gas transmission and distribution systems in which the pipes are manufactured from steel, cast iron, copper and plastics (UPVC and PE), and qualify for use in termsof the relevant Section herein. This includes dual phase flow in natural gas pipelines. Gas transmission and distribution systems within the scope of this standard comprise all pipelines, mains and gas service pipes up to the consumer's meter inlet within the limits defined by Fig. 1.1. This standard also covers the conditions of use of elements of these piping systems, including but not limited to pipe, fittings, flanges, bolting, gaskets, regulators,pressure vessels, pulsation dampers and pressure-relief devices. This standard does not apply to the following:(a) Design and fabrication of pressure vessels covered by AS 1210 or other approved pressure vessel codes; or to LP gas installations covered by AS 1596.(b) Pipe or bottle type holders or containers.(c) Piping beyond the consumer's meter inlet which is governed by the gas supply authority's installation rules.(d) Petroleum processing plants, gas manufacturing plants, industrial plants or mines.(e) Vent piping to operate at substantially atmospheric pressure for waste gas of any kind.(f) Well-head assemblies, including control valves, and flow lines between well-head and trap or separator, or casing and tubing in gas or oil wells.(g) Manufacture of proprietary items of equipment, apparatus or instruments.(h) Petroleum and other liquid transportation piping systems or liquid slurry lines.It is also not intended that this standard be applied retroactively to existing installations in so far as design, fabrication, installation and testing at the time of construction are concerned. Further it is not intended that this standard be applied retroactively to established operating pressures of existing installations except as provided for in Section 11. However, provisions of this standard apply to operating and maintenance procedures of existinginstallations, and to existing installations when they are modified to operate under conditions within the scope of this standard.