Risk assessment

The risk assessment is a duty of the manufacturer of a machine. EU machinery law requires the manufacturer to identify the hazards arising from the machine, estimate the risks and design and build the machine taking the results into account. EN ISO 12100 describes the method.

It is a design tool, not a closing document. If it is written only when the machine is finished, all that remains are guard fences and warning signs – the weakest means.

The standard divides the procedure into fixed steps that are repeated until the risk has been adequately reduced.

Risk is the combination of the severity of possible harm and the probability of its occurrence. That probability in turn is made up of three elements: how often and for how long persons are exposed to the hazard, how likely the hazardous event is, and whether the harm can still be avoided or limited.

With manually guided devices the first point weighs heavily: the operator is permanently within the range of movement of the load.

The order of protective measures is prescribed. First, inherently safe design: eliminate or reduce hazards, for example by positive locking instead of a friction grip, or by limiting forces and speeds. Then safeguarding and complementary protective measures: load holding on loss of energy, interlocks, guards. Finally, information for use: notices on the machine and in the instructions about the remaining residual risks.

A later step must not replace an earlier one that would have been possible.

The machinery risk assessment looks at the machine and is the manufacturer’s business. The workplace risk assessment – Gefährdungsbeurteilung in German law – looks at the workplace and is the employer’s business. It builds on the manufacturer’s information but reaches its own conclusions: installation site, parts handled, qualification of the operators, interaction with other work equipment.