his view is that buffer tanks or any other part of the system opperating above 3.4 bar may in theory need to tested and certified.

Does this mean they dont need to in the rules but theroeticaly there should be a rule about it?


All pneumatic components used with pressures greater than 50 psi (3.4 bar) MUST BE rated / tested to at least the maximum pressure available in that part of the system.
You may be required to provide documentation / certification to support this.

How is MUST BE an ambiguity?