Am 01.03.2021 um 15:29 schrieb T i m:
[..]

AFAIK there is no (mandatory) requirement to have such placed under
the regulations if it's under 250 bar/l.

So, if the OP's compressor is 25l and 120psi (8.3 bar) then it's only
210 bar/l so well under the threshold (and likely why the regulations
are set at that level or compressors are made to that spec).

nitpicking:
Bar*l not bar/l