Compression spanner

A compression spanner is an open-ended or adjustable spanner used to tighten the brass nuts of compression fittings on copper, chromed or plastic pipework. The spanner provides controlled leverage to compress the olive against the pipe and form a watertight seal. Excessive tightening can crush the olive, distort the body or split the pipe, so engineers use feel and manufacturer's torque recommendations to set the correct tension. Two spanners are typically used together: one to hold the body of the fitting, and one to tighten the nut, preventing the fitting from rotating against the pipe. Compression fittings are commonly used inside London flats on visible pipework, where they offer a low-skill, soldered-free alternative to capillary joints under the Water Supply (Water Fittings) Regulations 1999.