This AD 2000-Merkblatt applies to safety accessories guarding against excess pressure for pressure vessels in which an unacceptable excess pressure is prevented by the opening of safety valves or closing of safety shut-off valves.
AD 2000-Merkblatt A2-2015 history
2015AD 2000-Merkblatt A2-2015 Equipment, installation and marking of pressure vessels.Safety devices against excess pressure - Safety valves