Compression fittings are one of the most versatile fittings available as they can be used on copper or plastic pipe providing the correct insert is used. Often copper pipe is joined using solder joints by using either end feed fittings or solder ring fittings but the use of these is limited especially if you are somewhere where a blowtorch is not permitted. Compression fittings are often used to connect a copper pipe to a plastic pipe, this can also be done using a push fit fitting but many people distrust push-fit fittings.
Compression fittings are normally more expensive than end feed or solder ring because of the amount of work involved in making the fittings.
To join pipes together please see these articles- using end feed fittings - using solder ring fittings - using compression fittings
Compression fittings comprise of a brass body that is threaded and drilled out to the correct size for the pipe. A olive and compression nut are then used to grip the pipe. When the nut is tightened the tapered edges on the olive compress and grip the pipe. Some people use jointing compound on compression fittings but this is not necessary and is only recommended if the joint is leaking. There are two types of olive materials, Brass and Copper. The copper olives are often much easier to use as the copper is softer and so easier to compress when tightening the nut.
Compression stop end
A compression stop end can be used on copper or plastic pipe to blank it off, these are a very useful item as they can be used almost anywhere. Compression stop ends are normally available in 8mm, 10mm, 15mm, 22mm and 28mm +
Compression connector
A compression connector is used to join two pieces of pipe, these are useful because you can join a copper pipe to a plastic pipe using one of these (plastic insert required on plastic pipe). You can also get longer versions of these that can be used to repair damaged pipes. Compression connectors are normally available in 8mm, 10mm, 15mm, 22mm and 28mm +
Compression reducing connector
These are useful when you need to reduce the size of the pipe, there are not many different sizes of these as it is cheaper to reduce the pipe using other methods.
Compression tank connector
Tank connectors are available almost exclusively in compression as the heat generated during soldering would damage the tank. These are used to join pipework up to water tanks, such as the header tank in a central heating system. Compression tank connectors are normally available in 15mm, 22mm and 28mm +
Compression wall plate
These are used when installing a bib tap (outside tap). The tap has an half inch BSP thread in it which threads directly into the threaded hole on the wall plate. Compression wall plate's are normally available in 15mm, 22mm with either a 1/2 inch or 3/4 inch female thread to accept the bib tap.
Compression elbow
These are used for creating 90 degree bends in pipework. These can be difficult to tighten in some situations as you have to grip the body whilst tightening the nut. Compression elbows are normally available in 8mm, 10mm, 15mm, 22mm and 28mm +
Compression straight tap connector
These used to connect the water supply up to a basin or bath tap.
Compression tap connectors are available in 15mm x 1/2 inch, 15mm x 3/4 inch and 22mm x 3/4 inch.
Compression bent tap connector
This bent version is used to connect the water supply up to a basin or bath tap. Bent Compression tap connectors are available in 15mm x 1/2 inch, 15mm x 3/4 inch and 22mm x 3/4 inch.
Compression equal Tee
These are used when you need to branch off from a pipe of the same size. Compression equal Tee's are normally available in 15mm, 22mm and 28mm +
Compression reducing Tee
There are not as many different types of reducing Tee's available in compression fittings as it is expensive to manufacturer them, here is a 22-22-15 reducing Tee. If you require a different reducing Tee there are lots more available as end feed or solder ring
Please see this article on How to Use compression fittings
