For experienced professionals, navigating the complex world of plumber pipes and fittings is a breeze. Unless they have industry experience, this is rarely the case for the average homeowner. The average plumber supply store carries many types and sizes of pipe fittings made from diverse materials.
Choosing the right fitting requires careful attention to the job at hand. Once home handymen know what they plan to do and what kinds of pipes they will be working with, it's time for them to start investigating options. Homeowners can find out everything they need to know to find the right plumbing products below.
Pipe Fitting Materials
Most fittings are made of the same material as the pipes they are meant to join. That means a plumber fitting PVC pipes generally wants to purchase PVC fittings, while someone fitting copper pipes would want to buy copper fittings, and so on. There are, however, a few exceptions to the rule.
Determining which material will be right for the job is the easy part. Choosing the right fitting type can be much more complicated. Let's take a look at the types of pipe fittings to clarify some misconceptions and intended uses.
Elbow fittings are used to join pipes of the same or different diameters in situations where the direction of flow must be altered. Stock options are available in three angles: 90o, 45o, and 22.5o. To join pipes of the same size, use normal elbows. To join pipes with different diameters, use reducer elbows.
Reducers are designed to allow uninterrupted water flow between two pipes of different sizes. Concentric reducers are cone-shaped, while eccentric reducers feature a parallel edge to prevent cavitation.
Tee fittings are shaped like the top of a "T," meaning they have one inlet through which water enters and two outlets arranged at 90o angles to the inlet. Tee fittings with similar-sized inlets and outlets are called equal tees, while fittings with dissimilar-sized outlets and inlets are called unequal tees.
Homeowners will also have their choice of straight tees and reducing tees. The first is used to run pipes of the same size as the tee branch. The latter is used to connect tee fittings that are smaller than the pipe.
Cross fittings feature four openings connected at a central point. One of the openings is an inlet, while the other three are outlets. The outlets typically feature solvent-welded sockets or female threads. Cross fittings are used almost exclusively in fire sprinkler systems.
There are two types of couplings: compression and slip. Compression couplings are used to connect two pipes of the same diameter and generally feature rubber gaskets or seals on each side.
Slip couplings consist of two pipes. The inner pipe slides into the outer one, allowing plumbers to alter the length accordingly. Both types of couplings are used primarily to replace damaged sections of pipe.
Unions serve a similar function to those of couplings. They're designed to prevent water leaks where two pipes of the same diameter meet. The primary difference is that while couplings are permanent, unions can be removed. They consist of a nut with male and female threaded ends, allowing homeowners to detach them without risking damage to the pipes.
Plumbers use olets when standard fittings aren't suitable. There are many types of olets, each of which is used for a different purpose. Standard olets include:
Plugs are designed to close pipe openings. They usually feature male threads and are commonly installed during repairs or plumbing inspections. Plumbers use plugs when they plan to remove them instead of leaving them in place.
Caps are similar to plugs, but they're meant for long-term use. They feature female threads designed to be screwed directly onto the pipe. When installed correctly, caps are both liquid- and gas-tight.
Adapters are used to connect different-sized pipes or change the connection type for similar-sized pipes from male to female and vice-versa. They come in three types: straight-thread, male, and female. Plumbers use them primarily for extending or terminating pipe runs and transitioning from piping to tubing.
Pipe nipples connect pipes to appliances. They can also be used to connect straight runs of pipe. They feature two male ends and come in five types:
Barbs have one male end and one tapered end. They're used primarily in gas and air vent pipes, but can also be used in low-pressure water pipes. The barb's tapered, ridged cone end is designed to grip the tube or pipe's inside to provide a permanent seal.
Saddle tees have one specialized application: they're used to add tee fittings to pipes without requiring contractors to make extra cuts or welds. They're commonly found in irrigation systems.
Wye fittings feature one inlet and two outlets that leave the fitting in a 45o branch. They are used to connect vertical and horizontal drain pipes, where the angle helps to reduce friction and turbulence.
Flanges are used primarily in industrial settings since they can handle greater amounts of pressure than most residential fittings. They're used to connect pipes and form a seal. Residential applications for flanges are generally limited to pumps and mounting toilets to floors.
Bushings are similar in appearance to small screws. Their use is similar to that of reducers, but they are generally smaller and are often used to connect small-diameter pipes to large-diameter fittings.
The Bottom Line
This article has covered the most common plumbing fittings used in residential settings, but it's not a comprehensive list. Homeowners who are having trouble figuring out what they need can contact a customer service representative. There may be a more specialized product that will be a better fit for the application.