How Air Compression Fittings Work

Basics

Compression fittings are most popular in the electrical and plumbing industries, and are used mostly to attach two different types of piping together. This piping is normally, but not always, PVC and copper. The fitting is made of a material that will work well with both types of pipe that being joined. The seal is formed through the compressing of the attachment to the pipe, and if done properly there will be no leaks. The compression fitting is popular due to its ease of use.

Parts

The fitting is made up of an outer section called the nut and an inner ring typically called a compression ring. The ring has been known to be referred to as a ferrule or olive as well and is normally made out of brass or copper. The piping is placed into the end of the nut and the nut is tightened. As this happens, the piping is pressed against the inner ring and forces the ring to mold to the shape of the pipe. Once tight, the seal is created by the pressure of the nut and the ring pressed into the pipes.

Warning

The one thing that should be cautioned in using compression fittings is the tightening process. If it is too tight, the fitting can become useless because the ring will become deformed and leaking will occur. Since it is hard to acquire just a compression ring to replace one that is damaged, generally the entire fitting will have to be replaced. The rule of thumb is to tighten the fitting with the fingers and then tighten it just half a turn more. Test the fitting to see if there is any leak. If there is, tighten slowly until there is no more leak.