Fittings come in a variety of shapes and sizes and are used to connect one or more pipes and/or change the direction of a straight pipe line. According to codes, any pipe change in a drainage system must have a radius of curvature large enough to avoid silt accumulation and provide suitable hydraulic flow characteristics. These fittings are known as fittings or sanitary-type fittings, and they must be used in drainage systems according to the code. Drain-pattern fittings aren’t required for vent pipes.
Bend (sweep) – These types of fitting are used to change the direction, especially in sanitary drainage systems. A 12 bend is a 90 fitting, which is available as either a short sweep or a long sweep (i.e., short or long radius curvature). A 1/8 bend is a 45 fitting, and a 1/16 bend is a 2212 fitting.
Return bend – a pipe fitting which provides 180 deg. change in direction.
Elbow – a fitting having a 90 deg. bend in direction with a very short radius. It is suitable for use in water supply system and vent system.
Straight elbow – an elbow having both ends internally threaded and of the same diameter.
Street/Service Elbow – a malleable iron fitting for threaded pipe having a 45° or 90° bend, with an inside thread on one end and an outside thread on the other.
Wye or Wye Branch – These types of fitting are used to connect a branch pipe to a straight run of pipe at a 45° angle. Wyes are available with end connections that are of the same size or with various combinations of reduced pipe sizes in any direction.
Combination Wye Branch – a single fitting which is a combination of a wye branch and 1/8 bend; used in a drainage system in changing the direction such as from horizontal (branch) to stack or from vertical (stack) to horizontal (house drain/building drain).
Tee – used to connect a branch pipe into straight run of piping at a right angle. Where flow characteristics are important, such as in the drainage system, code requires that a sanitary tee be used.
Straight Tee-a tee having all openings the same size.
Street Tee/ Service Tee – a malleable iron fitting for threaded pipe in the form of a tee having an outside thread on one end and an inside thread on the other and on the branch.
Sanitary Tee – These types of fitting are used as fittings for soil pipes and are designed with a slight curve in the 90° transitions so as to channel flow from a branch line toward the direction of the main flow.
Tapped Tee– a bell-end tee, which has a branch that is tapped to receive a threaded pipe fitting or a threaded pipe.
Coupling – This types of fitting is a short, internally threaded section of pipe, used to join two pipes. To allow the pipe to seat, it has tiny ridges on the inside surface of the fitting.
Socket – it has similar application as the coupling but its ends are enlarged to provide additional mechanical strength.
Adapter – a type of fitting to connect pipes of different materials such as from galvanized steel pipe to plastic or synthetic pipe, the galvanized pipe being threaded and the plastic having no threads; a type of transition fitting.
Nipple – a short length of pipe with external threads at each end; used to join couplings or fittings.
Close Nipple – a type of nipple having both ends externally threaded.
Cap– an internally threaded fitting used to close the end of a pipe.
Plug-an externally threaded usually with square head; used to close the end of pipe.
Bushing – a pipe fitting, which is threaded on both the inside and the outside so that it can be used to connect two pipes (or other fittings) of different sizes.
Flange – a fitting with a projecting collar along the edge; used on installation requiring an increased area converge for added mechanical strength.
Union/Union Patentee – a pipe fitting used to connect the ends of two pipes, neither of which can be turned; consist of three pieces, the two end pipes (having inner threads), which are tightened around the pipe ends to be joined, and a center piece which draws the two end pieces together as it is rotated, affecting a seal.
Union Elbow – A pipe elbow having a union type coupling on one end, so that the coupling end may be connected to the end of the pipe without running the pipe.
Bend offset – A change in the direction of a pipeline (other than the 90°), e.g. by a combination of elbows or bends, which brings one section of the pipe out of line with but into a line parallel to another section.
Reducer – a pipe fitting with inside threads, larger at one end than at the other. Increaser – – a tapered coupling used for joining a pipe to another of larger size.