Where the Ministers have been satisfied, before issuing a certificate of approval (whether issued before or on or after 1st September 1977), that the noise levels inside safety cabs of the model to which it relates, when fitted to tractors of descriptions specified in the certificate, would not be more than 90 dBA if tested in accordance with British Standard Specification No. B.S. 4063:1973, the approval mark on an approved safety cab of that model shall be the following symbol:
(2)
In any other case the approval mark on an approved safety cab shall be the following symbol:
