Pipe Fittings are an important piping component that helps in changing the direction of the flow such as elbows, tees, changes the size of the pipe such as reducers, reducing tees, distribute the water supply from the main pipe to other pipes of equal size or lower size, etc. connect different components such as couplings and stop the flows such as Caps. In plumbing, many types of fixtures are joined with the help of various types of material such as metallic or plastic, as per the requirement. Pipe fittings vary depending on the type of pipe used. Fittings are fixed in the plumbing system to join straight pipes or any section of tubes. Any part used in connection with water supply, distribution, measurement, controlling, use and disposal of water is known as a pipe fitting. Pipe fittings basically include the range of components that are used to connect pipe ends for in-line, multi-port, offset and mounting configurations. Pipe fitting cross sections are mostly, but not always, circular in shape to match with the pipe section with which they are connected.
Types of Pipe Fittings
There are different types of pipe fitting used in piping.
1. Adapters: Adapters are an extremely important pipe fitting that extend or terminate pipe runs. They are used to connect dissimilar pipes. These fittings are somewhat similar to pipe couplings, with the difference that they connect pipe of different types, one of which is an IPS (Iron Pipe Size). These pipe fittings make the ends of the pipe either male or female threaded as per the need. This permits unlike pipes to be connected without any need of extensive setup. They are mostly used for PVC and copper pipes.
2. Elbows: Elbows, also known as “ells,” are used to change the direction of the flow. A common example of an elbow fitting in the home is the piece that extends from the wall of your shower to which the shower head connects. They are majorly available in two standard types – 90 and 45 degree angles owing to their high demand in plumbing.
3. Couplings: A coupling is a pipe fitting used to stop leakages in broken or damaged pipes. The pipes to be connected should be of the same diameter. The two kinds of couplings used in plumbing are regular coupling and slip coupling. The basic function of Couplings and Union is simply to connect two pieces of pipe or tubing. Therefore, couplings and unions are generally quite short fittings. The regular coupling is arranged between the two pipes to prevent further leakages with the help of rubber seals or gaskets on the both sides. The slip coupling itself contains two pipes to repair the damaged lengthy pipes.
4. Olet: These fittings are used when the standard size of the fittings fails to serve the purpose. Whenever branch connections are required in size where reducing tees are not available and/or when the branch connections are of smaller size as compared to header size, olets are generally used.
5. Union: This type of pipe fitting is almost similar to coupling in terms of functions i.e. to connect two pieces of pipe or tubing, but just with a difference, i.e. couplings are designed to be somewhat permanent and are often welded in place or secured by a series of bolts and nuts, while unions are designed to be easily removed at any time.. A variety of dielectric unions are used to join pipes made of different materials to avoid any kind of galvanic corrosion between them. These pipe fittings comprise of a nut, female and male ended threads.
6. Nipple: It is a piece of pipe having thread at both sides, and
could be used for short extension of plumbing lines. It can also be used for connecting two fittings within small distance.
7. Reducer: This pipe setting is used to reduce the flow size of the pipe from the bigger to smaller one. There are two kinds of reducers- concentric reducer and eccentric reducer. It is used to connect pipes of different diameters. A
reducer may be of various types like reducer tee, reducer elbow and reducer socket. The former one is in the shape of a cone used for gradual reducing of the size of the pipe. The latter one has its one edge facing the mouth of the connecting pipe reducing the chances of air accumulation.
8. Tee: This T-shaped pipe fitting used in the plumbing system has one inlet and two outlets arranged at an angle of 90 degrees to the main pipe. Pipe tee is used for distributing or collecting the fluid from the run pipe. There are two types of Tee used in piping, Equal / Straight Tee and Reducing / Unequal Tee. This kind of fitting is used to connect the two pipes and make their flow direction as one. If all the three sides of this fitting are same in size, it is called equal tee, otherwise unequal tee.
9. Cross: Cross is also known as four-way pipe fitting. A cross has one inlet and three outlets (or vice versa). Generally, crosses are not used in process piping to transport fluid. But forged crosses are common in the fire water sprinkler line.
10. Flanges: A flange is another pipe fitting used to connect pipes, pumps, valves, and other components to form a full-fledged piping system. They come with a flexibility of easily cleaning or inspecting the whole system from within. They are fixed to the pipes using welding, threading or screwing techniques and then finally sealed with the help of bolts. They are used in residential pump systems and majorly for industrial purposes.
11. Caps & Plugs: A cap, as its name suggests, is a cap that goes over the end of a pipe, creating a dead end. Plugs also stop up a pipe or tube system, but are plugged, like a stopper, into the end of the pipe. The plugs are fitted inside the pipe and threaded to keep the pipe for future use. There are a good number of ways a cap can be applied to the pipe like soldering, glue, or threading depending on the material of the pipe.
12. Bushings: It is used to join two pipes of different sizes. Bushings are not always threaded inside out and occupy very little space in comparison to a union or coupling used for the same purpose. A type of backflow preventer installed in a pipe run that allows water to flow in only one direction.
13. Wyes: It is a type of Tee which has the branch at a 45° angle, or an angle other than 90°. Wye tee allows one pipe to be joined to another at a 45° angle. This type of tee reduces friction and turbulence that could hamper the flow. Wye tee is also known as a lateral.
14. Valves: Valves are used in the plumbing system to stop the flow of gases or liquids. There are of three types – throttling, isolation, and non-return. But the one unifying attribute is that they control the flow of fluids and gases through a system.Some common types of valves are butterfly, gate, globe and ball. Sink and shower/bathtub faucets are among the most common types of valves.
A “barb” or “hose barb” fitting is used to connect flexible hose or tubing to pipes. A barb fitting typically has a male-threaded end used to mate with female threads. The other end of the fitting has either a single- or multiple-barbed tube having a tapered stub with ridges, which is inserted into a flexible hose to secure it.
16. Diverter tee: This kind of a tee-shaped pipe fitting is commonly used in the pressurized hydronic heating systems to redirect a part of the flow from the main line to the side branch connected to a heat exchanger.
Specifications of Pipe Fittings
- Type: 45, 90, 180 Deg. Long/Short Radius Elbows, Equal Tees, Reducing Tees, Equal Crosses, Reducing Crosses, Concentric Reducers, Eccentric Reducers, Caps, Barred Tees, etc.
- Pipes Bend:
1. Size: 3″-48″
2. Radius: 3D, 4D, 5D, 6D, 8D, 10D.
3. Angels: 22.5Deg, 30Deg, 45Deg, 60Deg, 90Deg.
- Pipe Fitting Standard: ANSI B16.9, ANSI B16.11, ANSI B16.28, DIN 2605, DIN2615, DIN2616, JIS B2312, JIS B2313.
- Pipe Fitting Material:
Carbon Steel: ASTM A 234 WPB, A420 WPL1, WPL3, WPL6, ASTM A860 WPHY 42, WPHY52, WPHY60, WPHY65, WPHY70.
Stainless Steel: ASTM A403 WP304/304L, WP316/316L, WP321, WP347.
Alloy Steel: ASTM A234 WP1, WP5, WP9, WP11, WP12, WP22, WP91.
Duplex & Super Duplex Steel: ASTM A815 UNS S31803, UNS S32750, UNS S32760.
Pipe Fitting Schedule:
Carbon Steel & Alloy Steel: STD, XS, XXS, SCH10-SCH160.
Stainless Steel: SCH5S, 10S, 40S, 80S.
- Pipe Fitting Size:
Carbon Steel: 1/2″-96″.
Stainless Steel: 1/2″ – 24″ (Seamless and Welded), 26″ – 72″ (Welded)
Types of pipe joints
Pipe fittings are used to connect pipes or tubes in two ways:
- By threading: Threaded pipes screw together to connect or join. Generally metal pipes are threaded and they have threaded fittings.
- By slip fit: Slip fit pipes use sleeves that slip into one another. The plastic pipes are either threaded or slip fit.
Various types of pipe joints are as follows:-
1. Threaded joint
2. Welded joint (butt welded, socket welded)
3. Brazed joint
4. Soldered joint
5. Grooved joint
6. Flanged joint
7. Compression joint