Risk estimation studies in the context of a machine control function

Safety of Machinery: Significant Differences in Two Widely Used International Standards for the Design of Safety-Related Control Systems

“…Hietikko, et al [33] discussed and compared three risk estimation case studies for one control function of a machine using ISO 13849 and IEC 62061. Significant divergence was detected in the risk parameters of all the case studies, and thus the required safety integrity level from IEC 62061 and performance level from ISO 13849 of the pre-defined control function varied.…”

Contribution of dynamic experience feedback to the quantitative estimation of risks for preventing accidents: A proposed methodology for machinery safety

“…Moreover, the range of tools available means that risk estimation results vary depending on the tool used, much as they do depending on who performs the estimation (Hietikko et al, 2011;Ball and Watt, 2013). In the frame of this paper, if several safety practitioners in a company evaluate the risk related to a given hazardous situation, they may come up with different results when using the same tool.…”

Comparing performance level estimation of safety functions in three distributed structures

“…The estimation of these parameters may be challenging. Advice for the estimation is given in many sources (for example [1,5,17]), but still the estimation results may vary [4]. Thus this method can be considered as more or less subjective.…”

“…A part of these requirements come as a result of preliminary hazard analysis (PHA) or risk analysis, which is done early in the design process according to the basic machinery safety standard ISO 12100 [3]. The basic architectural decisions for arranging the safety measures are done based on PHA [4,5]. In addition, the required performance level (PL r ) for a safety function can be defined based on PHA.…”

“…The PL r for a certain safety function is defined either in a machine specific standard or it has to be defined using a risk analysis [6], for example, risk graph technique. However, it has been detected that the PL r may be defined in several ways due to several different reasons [4]. This may provide different PL r for the same safety function, which may also influence on the implementation of the safety function.…”