Apr 5, 2019 · The EN/ISO 13849-1 machine safety standard uses a qualitative risk graph, or flow chart, to assign a performance level (PL), based on three criteria: severity of injury; frequency and/or exposure time to the hazard; possibility of avoiding the hazard or limiting the harm

The performance level (PL) is a value used to define the ability of safety-related parts of control systems to perform a safety function under foreseeable conditions. On the other hand, the required performance level (PLr) is used in order to achieve the …

The performance level is a discrete level used to specify the ability of the safety related parts of the control system to perform a safety function under foreseeable conditions. The required performance level (PLr) is the mandatory performance level of a machine to reduce risk.

PL (Performance Level) is used similar to the safety integrity level when calssifyong safety classes. The performance level falls under the standard ISO 13849. This classification takes place from PLa to PLe.

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. The ISO and B11 standards are two of the most widely recognized machinery safety standards that address performance levels.

The outcome of the assessment is the required Performance Level (PL) for the individual safety functions, which are intended to minimise the risks. PL a corresponds to a low risk, PL e to a high risk.

Performance levels are specified as discrete levels—PLa, PLb, PLc, PLd and PLe—and are only determined for complete safety circuits or safety devices. Here are some of the quantitative and qualitative parameters that determine PL: Circuit Structure. The structure of a safety circuit depends on the arrangement of the components and diagnostics.

Frequent exposure of an “F2” rating requires a minimum Performance Level d (PLd) for compliance. Seldom exposure could require a Performance Level of c or d, depending on the possibility of avoiding or limiting the hazard

Performance levels run from PLa (least reliable) to PLe (most reliable, for the highest risk applications), they are based on the probability of dangerous failure per hour (PFHd) of the safety related parts of the control system (SRP/CS).

The reliability level of such a safety system is classified with a Performance Level (PL) level from “PLa” to “PLe”. If there is talk of a required safety level, we refer to it as “PLr”. This harmonised standard deals with the control engineering safety aspects of a machine.