The aim is to prevent injury from the hazard of stored energy due to system failure. Pressure system users/owners must show that they know the safe operating limits, mainly pressure and temperature, of their pressure systems, and that the systems are safe under those conditions. They need to: (a) have a suitable written scheme of examination before the system is operated; (b) ensure that the pressure system is examined in accordance with the written scheme; (c) ensure that the scheme is certified by a competent person.