The intent of this Standard is to provide for the protection of the general public, Gas Distribution Network operating personnel and the environment, and to ensure safe and reliable operation of Gas Distribution Network that reticulate gas to consumers. This Part 3 provides more detailed requirements for design, materials, construction, testing and commissioning of plastic mains and services within a network and is to be used together with Part 1. It covers gas distribution networks covered by Part 1 of this Standard for operating pressures up to 600 kPa.