IRSST - Institut de recherche Robert-Sauvé en santé et en sécurité du travail


Machine Safety : Hands-On Experimentation with Risk Estimation Parameters and Tools

Machine Safety : Hands-On Experimentation with Risk Estimation Parameters and Tools

From 1999 to 2003, 64,000 accidents and 100 deaths were determined to be attributable to hazardous machines in Québec industries. Although the tools and methods for estimating the risks associated with this equipment offer a first-line prevention strategy, an IRSST study, titled Experimental Analysis of Tools Used for Estimating Risk Associated with Industrial Machines revealed that they come in very different forms and that a number of their characteristics (e.g., parameters, architecture) can have a significant influence on the estimated level of risk.

As part of a thematic program intended to provide a better understanding of the processes for estimating the risks associated with industrial machines, a new study published by the IRSST explores the theoretical efficiency and limitations of a sample of these tools and methods. It evaluates the impact of these characteristics (e.g., parameters, architecture) and validates a number of risk estimation tool construction rules by means of an experimental study involving a variety of users, chiefly from industry.

This study opens up avenues for making a better selection of the means of estimating the risks associated with industrial machines best adapted to the hazards to which workers in Québec companies are exposed.


Six tools were analysed: 4 that were selected from a list of 31 drawn from earlier studies, as well as tools provided by the IRSST and the Commission des normes, de l’équité, de la santé et de la sécurité du travail (CNESST), and by the Health and Safety Laboratory (HSL) in the United Kingdom. Some risk estimation parameters having flaws or potential biases were also selected.

The risk estimation tools and parameters were applied to concrete scenarios of machinery-related hazardous situations by a representative sample of industry stakeholders, occupational health and safety officers, joint sector-based association advisors and trainers from various sectors. They were all asked to give their impressions and preferences with regard to the different risk estimation tools, along with their reasons.


This study helps to understand the impact that flaws in the parameters and architecture of risk estimation tools used in machine safety can have on results of risk level estimations. The results show that these flaws can lead to low convergence of the risk levels arrived at by different subjects, for a given hazardous situation, and to subject dissatisfaction with tool performance and accuracy. In most cases, the subjects were able to recognize a flaw when it made it harder from them to choose the level corresponding to a given situation.