If you operate machinery in your facility, you know the importance of ensuring the safety of your workers. One way to do this is by understanding the performance levels required for the machinery, as specified in machinery safety standards. But what are performance levels and how are they used in machinery safety standards?
What are Performance Levels?
Performance levels, or PLs, are used to specify the safety requirements for the machinery based on the likelihood and severity of the hazards associated with the machinery. The performance levels are divided into five categories, PLa, PLb, PLc, PLd, and Ple, with PLe being the highest level of safety and Pla being the lowest.
Some Relevant Standards
The ISO and B11 standards are two of the most widely recognized machinery safety standards that address performance levels. The ISO standard, ISO 13849, Safety of machinery – Safety-related parts of control systems – Part 1: General principles for design, specifies the performance levels for safety-related control systems.
Performance Level Requirements
The requirements for each performance level vary depending on the standard being used. In the ISO standard, the requirements for each performance level are based on the probability of a failure of the safety-related control system, the severity of the consequences of the failure, and the level of independence of the safety functions. The requirements for each performance level in the B11 standard are based on the likelihood and severity of the hazards associated with the machinery, the reliability of the controls used to mitigate the hazards, and the level of protection provided to the workers.
Determining the Appropriate Performance Level
To determine the appropriate performance level for a specific application, you should consider the likelihood and severity of the hazards associated with the machinery, as well as the level of protection required for the workers. You should also consider the specific requirements of the relevant machinery safety standards and the intended use of the machinery.