An example of determining the performance level
On this page, we want to provide you with an example of determining the performance level. We hope this will eliminate any uncertainty on how to do the calculation.
Scenario: lift table in the workshop
In our example, the performance level for a standard lift table should be determined. It is used in a workshop to raise components to a height that is ergonomically more favourable. Due to its particular application, the lift table has to perform relatively few lifting movements.
Step 1: severity of the injury
First, the severity of the injury in a possible accident must be evaluated.
In the case at hand, there is only a risk if the lift table is lowered. In the worst case, body parts or limbs could get into the scissors or between the platform and the base frame. Although lifts are fitted with switching strips to prevent crushing between platform and base frame, this may not be taken into considered in determining the performance level. S2 must be selected, because if a body part or limb gets into the scissors the during the lowering action, serious (irreversible) injury is possible.
Step 2: frequency and duration of exposure to danger
As mentioned before, the lift table only has to perform relatively few lifting movements. It is also not necessary to reach into the hazard zone during operation. Based on this information, F1 can be selected.
Step 3: possibility of avoiding the hazard
In the event of damage, the platform of the lifting platform could, without special equipment, be accelerated almost at free fall acceleration in the direction of the base frame. However, lift tables come standard with a pipe rupture valve to prevent such a rapid lowering.
Since the operation of the pipe rupture valve is based on mechanical principles, and so not dependent on the controls, it can be taken into account in the risk assessment. P1 can be selected, because the use of the pipe rupture valve allows people enough time to move away from the danger area.
For the current example, this results in the path S2-F1-P1. The technical device which has to safeguard against bruising or crushing in the scissors or between platform and base frame must, therefore, meet performance level ‘c’.