scope:

This AD 2000-Merkblatt is applicable for systems of automatically controlled safety devices for the prevention of unwanted overpressures in pressure vessels of process plants, in circumstances where the use of safety devices in accordance with AD 2000-Merkblatt A 1 or AD 2000-Merkblatt A 2, or of pipe gauges, is not possible or would not meet the intended purpose. Systems of this kind are characterized by the fact that, by making use of process control engineering (PCE), they operate in such a manner that the service over-pressure does at no time exceed the permissible value by more than 10% (PCE-safety devices).