(1) An approval comes into force on the day specified in the approval.
(2) An approval (other than an emergency approval) remains in force for the period specified in the approval, unless earlier revoked.
(3) Subject to subsection (4), an emergency approval remains in force for the shorter of the following periods, unless earlier revoked:
(a) the period specified in the approval;
(b) 14 days.
(4) If an emergency approval is varied under section 17F, at the end of the period for which the approval remained in force (whether because of subsection (3) or this subsection) the approval continues in force for the shorter of the following periods, unless earlier revoked:
(a) the period specified in the approval;
(b) 14 days.