Corroded Fittings

At college we are taught never to put copper pipework in contact with cement, mortar or plaster because the lime present in those materials is corrosive. This fitting had been installed when the house was built new 40 years ago and had only just failed after the householder moved the pipe slightly which caused it to fracture.

When I removed it you could clearly see where the cement splash had been lying on the pipework and how the fracture line ran staight across where the cement had been.