Introduction
A container of PVC threaded fittings arrives at a UK distributor. The warehouse team picks up a 1/2″ male adapter, threads it into a 1/2″ female elbow, and it screws in smoothly — two, three turns, then it stops. It *fits*. It just never seals. By the time the leak shows up on a pressurised line, the container has been invoiced, installed, and is now a warranty claim.