Film-feed and pick-up reels

(1) The film-feed and pick-up reels on the projector shall be enclosed in fire-proof metal boxes, or both may be contained in a strong metal chamber below the projector, with film slots so constructed as to prevent the passage of flame to the interior of the boxes or chamber. (2) In constructing the metal boxes or chamber the parts shall not be joined with any material of a lower melting point than that of the boxes or chamber. (3) The openings through which the reels are inserted or extracted shall be provided with close fitting doors or covers which shall be kept firmly closed when the projection light is on.