Piston provers
18.—(1) A piston prover shall have been tested over its full working range within 12 months before use.
(2) The error on a piston prover shall not exceed the limits of error shown in Schedule 2 to these Regulations.
18.—(1) A piston prover shall have been tested over its full working range within 12 months before use.
(2) The error on a piston prover shall not exceed the limits of error shown in Schedule 2 to these Regulations.