ISO 8643:2017 establishes uniform requirements and test procedures for lowering control devices fitted on the boom, intermediate boom and arm cylinders of hydraulic excavators and backhoe loaders to control the rate of drop in the case of a hydraulic line failure or rupture. It is applicable to the lowering control devices of hydraulic excavators and the backhoe equipment of backhoe loaders used for object handling which are equipped with the standard linkage as defined by the manufacturer. On machines where alternative linkage combinations are offered, only the standard length defined by the manufacturer is subject to testing.