to rotate the engines for starting up. Large diameter pipework systems are used for air lines that convey compressed air over great distances, these are typically found on large industrial sites & research facilities. Fixed pipe systems are typically connected to a large industrial compressor, located remotely, in a plant room or dedicated space. The compressed air lines will be piped from the compressor to one or multiple point of use outlets. At the outlet of a fixed air line you will typically find a Pressure regulator installed upstream of the termination/outlet point, this allows the user to regulate the pressure and flow of air to suit the desired use. The regulator allows each outlet to be controlled independently, even though they are served by a common compressor and connected to the same system. As with hose air lines, Fixed pipe air lines must be manufactured with anti-corrosion materials, such as non-ferrous metals or plastics, to prevent internal corrosion from air moisture content and condensate. Commonly used materials for piped air line systems Aluminium - smooth bore, energy efficient pipework Galvanised carbon steel - medium and heavy weight pipework systems Stainless steel and copper compression jointed systems Plastics, ABS and MDPE pipework systems Piped air lines are typically installed with a fall gradient away from the outlet point, this is to allow any build-up of moisture within the pipework (due to internal condensation) to drain via the automatic tank drain or via a drain leg installed on the system. Branch connections to serve outlets are typically taken vertically off the top of the main supply line and then loop down to the outlet point. This is done as a safety precaution and to avoid damaging pneumatic equipment. A connection into the top of a main air line greatly reduces the risk of Condensation water or particulates being discharged at high velocity through the outlet. Uses Common uses of air hoses include: To supply compressed air to pneumatic hand tools. In road vehicles, between tractors and semi-trailers which use air brakes. In railway air brakes . To supply breathing gas to underwater divers from the surface, usually through a diving umbilical cable. References Tools