7. A person who tests, maintains or in the case of a stationary engine requiring no supervision under section 27 of the Regulation respecting stationary enginemen (chapter M-6, r. 1), starts-up or stops a stationary engine or installation of stationary engines under the supervision of the holder of a certificate of qualification of the category and class required to operate or supervise that stationary engine or installation of stationary engines is exempt from the issue of a certificate of qualification in stationary engine mechanics.