24. Aisles for transport of crucibles: The aisles used for the manual transportation of crucibles shall possess the following minimum widths:(a) 450 mm if the transporting of crucibles does not require more than 2 workmen and if moulds, placed alongside the aisle, are not more than 500 mm above the aisle level;
(b) 600 mm if the transporting of crucibles does not require more than 2 workmen and if the moulds, placed alongside the aisle, are more than 500 mm above the aisle level;
(c) 900 mm if the transporting of crucibles requires more than 2 workmen.