PART IV RAISING AND LOWERING, ETC

Heavy loads

47.  Where there is reason to believe that a load being lifted or lowered on a lifting appliance weighs more than twenty tons its weight shall be ascertained by means of an accurate weighing machine or by the estimation of a person competent for the purpose, and shall be clearly marked on the load:

Provided that this Regulation shall not apply to any load lifted or lowered by a crane which has either a fixed or a derricking jib and which is fitted with an approved type of indicator in good working order which—

(a) indicates clearly to the driver or person operating the crane when the load being carried approaches the safe working load of the crane for the radius of the jib at which the load is carried; and

(b) gives an efficient sound signal when the load moved is in excess of the safe working load of the crane at that radius.