Plumbing systems depend on joints that keep water moving while resisting leaks and service demands. Compression fittings provide a mechanical way to connect copper pipe without soldering: a nut tightens against an olive, creating the seal around the tube. This can be useful where open flames are undesirable or a joint may need to be dismantled. For plumbing work, fitting geometry and connection type both matter. A fitting can join two pipe runs, change direction or create a branch, while threaded ends can connect copper tube to another component. Australian plumbing references recognise compression fittings as an established copper-tube joining method, alongside press-fit, push-fit and capillary methods. AS 3688 includes compression fittings among metallic fittings used in water supply and gas systems, subject to its applicable requirements.