Glossary · Risk assessment and risk reduction
Complementary protective measure
In machine safety, a complementary protective measure is a protective measure that is neither an inherently safe design measure nor a safeguard, such as an emergency stop. ISO 12100 places it in the second step of the three-step method, together with safeguarding.
- Machine safety
- Risk assessment
In one sentence
Complementary protective measures, such as the emergency stop or means of escape, back up design and safeguarding; they are not a substitute for either.
Example
A robot cell has an emergency stop at each access door, provisions for freeing a trapped person and a lifting point for heavy parts, in addition to its perimeter guard.
How it applies
- Machine safety: ISO 12100 gives examples: components for the emergency stop function, measures for the escape and rescue of trapped persons, means for energy isolation and dissipation, provisions for easy and safe handling of machines and heavy parts, and safe access to machinery.
- Risk assessment: A complementary measure does not reduce the need for design measures or safeguarding. An emergency stop, for example, is not a substitute for guarding.
- Technical documentation: Describe location, function and testing of each complementary measure in the operating manual, and distinguish them clearly from the primary protective measures.
- Evidence: Emergency stop devices and isolation means need their own verification and periodic testing records.
Complementary protective measure vs. safeguard
A safeguard (guard or protective device) prevents access to a hazard or detects a person and stops the hazard. A complementary protective measure addresses situations such as emergencies, rescue or isolation when other measures are not enough.