Any user of pressure equipment shall cause such pressure equipment which for operational purposes is
equipped with a quick-actuating opening, to be provided with an interlock or other effective means for preventing -
(a) a rise of pressure inside the pressure equipment before the quick- actuating openings are in the fully closed
and locked position; and
(b) the release of the quick-actuating opening from the locked and closed position before the pressure inside
the pressure equipment has been reduced to atmospheric pressure or the pressure across the openings
has been equalised.