83. The following provisions shall apply to machinery spaces—
(a)the number of openings to machinery spaces shall be the minimum compatible with the proper working of the ship;
(b)windows shall not be fitted in machinery space boundaries;
(c)any machinery space of Category A which is accessible from an adjacent shaft tunnel shall be provided with a light-weight steel fire-screen door in addition to any watertight door; the fire-screen door shall be operable from each side and shall be located at the shaft tunnel side of the bulkhead.