What are the manufacturing license and grade regulations for valves?

A1
(1) Valves with a design temperature greater than 425°C and a nominal diameter greater than or equal to DN200
(2) Valves with nominal pressure greater than PN100 and nominal diameter greater than or equal to DN200

A2
(1) Valves with nominal pressure greater than or equal to PN64 and nominal diameter greater than or equal to DN200
(2) Valves with design temperature lower than -46°C

B1
Valves other than Class A1, A2 and B2

B2
Valves with nominal pressure less than or equal to PN40