(MEWPS) for tree work - Urban Access

4.3.2 Current safety featuresAll of the MEWPS used in the trials had similar safety features. A major safety feature is the loadsensing outriggers that trigger alarms, either visually or audibly or in some cases both, when themachine is not level. A further feature of this mechanism is that the machine will stop the operatorfrom increasing the instability and will only allow operations to regain stability.All the machines could also be operated from the platform or the base of the machine. This dualcontrol system allows the groundsman, who also has to be trained in MEWP operation, to lower themachine should the operator get into difficulty.Many machines now have several power options and many have power sources, either operatingpurely on engine power take off (PTO) diesel/petrol or battery power or combinations of theseoptions. Furthermore, there is an emergency hand pump, which is a common feature on allmachines. If ALL the power systems were to fail, the hand pump can still lower the MEWP.It is also a popular misconception that MEWPS can crash to the ground due to a hydraulic failure ofthe boom. This is unlikely to happen with today’s machine as many of the types now have safetylock/check valves on all the hydraulic cylinders which will allow only that section of boom/ram toretract into the hydraulic cylinder. The effect is immediate, preventing a dropping sensation. Thismovement is unlikely to initiate such instability as to cause the machine to topple over.All the platforms are load bearing tested to produce a safe working load (SWL) capacity, which isthe maximum that the basket will safely carry and includes all the operators tools and equipment.The branches of a tree are not load-bearing tested.The baskets of the machine are supplied with all round guarding and toe guards to preventoperators, tools and equipment from falling from the basket. Of the machines fitted with gates,some are spring loaded to close properly and all are fitted with safety catches to ensure properclosure.These safety features result in greater security to the operator and reduce the risk of injury incomparison with climbing.4.4 MACHINE RESULTSThe purpose of the trials was to evaluate each MEWP selected with regard to the following factors:Access – in reaching the tree and the crown in association with the maximum height andreach.Manoeuvrability – around the tree and within the crown in association with sidewaysmovement available.Terrain – with regard to soft conditions, gradients, side slopes and rough ground17