Compression fittings are couplings used to join tubes or small flow diameter pipes together using compression. They are often made from brass, copper or stainless steel and can be used to join PVC, nylon, plastic and copper tubing. They are very versatile and come in a variety of designs and sizes for plumbing projects in domestic, commercial, and industrial applications, from water mains and gas supplies to air conditioning systems. They are also known as compression joints, nuts or couplings.
Guidance covering the standards required for compression fittings and pipework can be found on the Health and Safety Executive website. Reputable suppliers, such as https://watkinspowis.co.uk/, will also be able to give advice on product selection for any given application.
They are easy to use and a good choice for pipes in confined spaces that could be difficult or a fire risk to solder.
How does a compression fitting work?
Compression fittings are simple devices which consist of three pieces: a tapered, threaded nut, a slim brass ring known as an ‘olive’ or ‘ferrule’, and a tapered insert. The barrel-shaped olive gets compressed between the nut and the fitting and creates a tight seal on the pipe. Olives cannot be easily removed once they have been compressed.
Most compression fittings are made from either brass or copper because they combine both strength and resistance to corrosion while being relatively low cost. Plastic and stainless-steel options are also available. Both brass and copper pipe fittings are excellent tools for joining copper pipes or plastic tubing because they create an effective, watertight joint between the pipes without soldering, which can be a difficult job.
Are compression fittings reliable?
They are very reliable if the pipe is correctly cleaned and prepped, and the compression fittings are suitable for the application and fitted correctly. They should be tight enough to make a watertight seal but not too tight, as the pipe could warp, or the thread could be damaged. This would encourage leaks and make removal more difficult, so it is important to install them correctly.