Propane gas pipes and tubing are manufactured from metallic and plastic materials, with each material designed for specific applications. Propane or liquid petroleum gas pipes are manufactured to state regulations and to building and fire codes, such as the National Fire Protection Association and Standard Gas Code.
Propane is a fossil fuel designated as a clean burning fuel that is commonly used through the U.S.; around 97 per cent of the propane used in the U.S. is produced in North America. Propane is a hydrocarbon, and the gas is produced from natural gas production and oil refining. The fuel is non-toxic, colourless and almost odourless. The uses of propane include outdoor grills, furnaces, water heaters and fireplaces. Propane is usually stored in tanks, and copper tubing is used to connect the tanks to underground pipes.
Each material used to transport propane gas to its final consumer destination is used due to the environment and location of the pipe. Pipes are described as rigid structures manufactured from iron, steel, copper, brass or plastic, while tubing consists of semi-rigid tubes manufactured from plastics or steel. Corrugated stainless steel tubing is commonly used to install propane gas because of its ease of installation; it's not difficult to manoeuvre a corrugated tube system around an existing structure. The regulations regarding the type of material used in pipe installations varies from state to state.
A propane gas pipe must be installed underground, according to Propane 101. Above ground pipes are not permitted, except where the pipe leaves a tank or attaches to an appliance. The underground installation of an LPG system is commonly inserted in a PVC sleeve or wrapped with tape to avoid corrosion that can occur in the harsh underground environment. Stainless steel propane pipes require the use of a sleeve or tape wrapping because of the corrosive nature of the metal. A pipe must be buried to a depth of between 12 and 18 inches to avoid crimping or crushing; the depth depends on the amount of traffic passing over the pipe. The diameter of a propane pipe relates to the size of the propane system installed.
Certain materials are not permitted in the installation of propane systems, including PVC, rubber and flex hoses that are liable to break or rupture. Polythene plastic is a common material permitted in the building codes of the majority of U.S. states. Municipal gas suppliers often use polythene piping to transport and supply propane to customers, while home installations often use metals such as copper that can be used for above-ground connections and below-ground transportation.