(7)Interlocking arrangements. - In each oven or drier efficient inter-locking arrangements shall be provided and maintained to ensure that-(i)all ventilating fans and circulating fans whose failure would adversely effect the ventilation rate or flow pattern, are in operation before any mechanical conveyor that may be provided for feeding the articles or substances to be processed in the oven or drier is put into operation;(ii)failure of any of the ventilating or circulating fans will automatically stop any conveyor as referred to in clause (i) as may be provided, as well as stop the fuel supply by closing the 'shut off valve and shut off' the ignition in the case of gas or oil fired ovens, and in the case of electrically heated ovens switch off the electrical supply to the heaters;(iii)the above said mechanical conveyor is set in operation before the above said shut-off valve can be energised; and(iv)the failure of the above said conveyor will automatically close the above said shut off valve in the case of ovens and driers heated by gas, oil or steam and deactivate the ignition systems, or cut off the electrical heaters in the case of electrically heated ovens or furnaces.
