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

Mechanical and Physical Risk Prevention

Mechanical and Physical Risk Prevention

Priority issues

Every year, many workers are victims of work-related accidents (some of them serious or even fatal) or contract occupational diseases because they are exposed to numerous hazards posed by the machines they operate and their work environment. In terms of prevention, actions can be taken at the source, in the work environment, with workers themselves to eliminate the risks, or, when measures cannot be put in place to eliminate or reduce risks at the source, through the workers' use of personal protective equipment. The OHS, scientific, and technological issues studied in this field concern the risks associated with:

  • machines;
  • mechanical risks;
  • noise and vibration;
  • heat stress;
  • excavations;
  • falls from heights, on the same level, and due to slipping.

How are the priority issues put into perspective?

Above all, we use:

  • statistical data;
  • research mapping;
  • scientific monitoring and surveillance;

 and we pay close attention to the needs expressed by workplaces.


The researchers in this field focus specifically on the assessment and reduction of physical and mechanical risks that could jeopardize worker health and safety, taking into account workers’ interaction with the machines around them and their work environment. The machines may be of the fixed or mobile industrial type or hand power tools. The main physical risks include:

  • noise;
  • hand-arm and whole-body vibration;
  • heat stress.

The mechanical risks include:

  • cuts;
  • lacerations;
  • needle punctures;
  • crushing;
  • contact with machines;
  • falls from heights, on the same level, and due to slipping;
  • trench cave-ins.

Their research efforts involve producing methodological and metrological tools or carrying out simulations, as well as testing and evaluating methods to help those responsible in the workplace diagnose and assess risks more effectively. Efforts also focus on developing support tools for selecting, enhancing, and designing prevention solutions, taking the human factor into account.

Three research orientations have been defined in order to achieve these goals:

  • Assessment of the mechanical and physical risks generated by machines or the work environment;
  • Reduction of mechanical and physical risks;
  • Taking the human factor into account in the evaluation and control of mechanical and physical risks.

Current programs and themes

Assessment of risks associated with machines

The aim of this program is to conduct studies that will provide enterprises with robust, reliable tools for assessing (analyzing and evaluating) the risks associated with machines. This step is prerequisite to identifying appropriate ways of reducing risks.


The aims of this program are to enhance understanding of the problems related to lockout, study the components of a lockout program and the conditions conducive to its application, evaluate its application in workplaces, and identify alternatives when the program cannot be applied.  

Hand power tools

The work carried out within this transverse research program, which concerns both noise and vibration, is aimed at developing knowledge of the acoustic and vibratory performances of hand power tools, proposing ways of reducing these vibration and noise levels and disseminating this information so that tool models with lower impact levels can be identified. More specifically, this means identifying the mechanisms whereby tools generate noise and vibrations in work situations, evaluating them on laboratory test benches that simulate working conditions, and clarifying dose-effect relationships for hand-arm vibrations.

Acoustic barriers and noise-control materials

The aim of this program is to develop reliable, user-friendly, transferable methods that can be adopted by workplaces to help reduce worker exposure to noise. This can be achieved by developing tools to support both the design of noise-reduction solutions (for example machine enclosures) and the evaluation of materials’ acoustic performance, while also evaluating and even designing new noise-abatement technologies based on the use of barriers and innovative materials.

Evaluation and modelling of personal hearing protectors

The aim of this program is to explore methods for evaluating the real protection offered by hearing protectors in the workplace and to develop support tools for designing efficient and more comfortable personalized hearing protectors.

Shoring and shielding systems

This program focuses on providing preventionists with tools to help them choose appropriate means of protection against trench cave-ins, taking into account soil type and conditions, as well as water table conditions. It also seeks to support the work of the review committee for the Québec Safety Code for the Construction Industry.

Resistance of protective gloves and clothing to mechanical and physical hazards

The aim of this thematic program is to evaluate the resistance of protective gloves and clothing to mechanical hazards (e.g. cuts, perforation, tears), while also integrating aspects related to human factors (e.g. adherence and dexterity associated with gloves, heat stresses associated with clothing). The work is aimed at developing knowledge of the behaviour of materials with regard to different types of hazards and of the impact of equipment use on physiological functions, motricity, and comfort. This in turn makes it possible to design tools for selecting protective gloves and clothing, develop testing methods, establish equipment selection criteria, and contribute to the development of standards and more efficient products. The program concerning protective gloves and clothing in relation to chemical and biological hazards is managed by the Chemical and Biological Hazard Prevention field.

Protection against falls from heights

The aim of this program is the development and application of test methods for identifying the personal protective equipment (lanyards, safety harnesses, belts, anchor points) and collective protective equipment (guardrails, horizontal lifelines) that are best adapted to different work environments, while taking human factors into account. It also seeks to provide a basis for designing new products and defining selection criteria and to support the development of standards. 

Slips and falls on outdoor surfaces

The aim of this thematic program is to identify design requirements for, and the techniques required to select, boots/footwear offering the best resistance to slips on outdoor surfaces, particularly on ice, snow or surfaces that are wet from winter rain, and for variety of work environments. Aspects related to comfort and those wich may impact on the risk of slipping are also investigated.

Audible alarm signals in the workplace

This thematic program concentrates on communication in noisy environments from the perspective of audible alarm signals. For example, it studies the effect of hearing protectors on various measurements of acoustic perception during the use of alarms (tonal or broadband).

Statistical data: priority issues explained

Based on the 2005–2007 five-year indicators, accidents related to fixed machinery represent 5.3% (4,923) of all accidents involving time-loss injuries annually.

The severity of injuries caused by machine-related accidents and the fact that machines are used in most activity sectors impelled the CNESST to apply a “Sécurité des machines” (machine safety) action plan starting in March 2005. These types of accidents affect mostly manual labourers (85%) and young workers (ages 15 to 24). Young workers post a frequency rate twice as high as that of workers ages 45 and over. The most frequent traumatic injuries involve the hands and fingers, and consist primarily of open wounds, bruises, and fractures. Injuries to the upper extremities represent approximately 20% of all injuries compensated by the CNESST. Between 2006 and 2009, an average of 13 machine-related deaths occurred annually.

Of the other mechanical risks studied in this field, the entrapment of workers in the bottom of trenches due to wall cave-ins causes at least one or two deaths a year, representing 1% of all work-accident fatalities.   

Falls from heights continue to be a major source of work-related injuries (9.8% of work-related injuries compensated in relation to traumatic accidents and 5.6% of all compensated work-related injuries annually) and of deaths on the job (11 of the 68 accident-related deaths accepted in 2011).

The relative numbers of falls on the same level and slips/trips without falling rose from 9.4% to 12.2% of all injuries accepted between 1998 and 2008. For the 2005 to 2007 period, falls on the same level and slips/trips without falling ranked first among the most frequent type of accidents.

Nearly 20% of traumatic accidents result in cuts and lacerations. Most of these accidents affect fingers and hands. Needle punctures and perforations represent 6.2% of all traumatic accidents. Injuries attributable to needles and syringes account for 2% of the traumatic accidents caused by needle punctures and perforations.

Between 2005 and 2008, the number of noise-related injuries rose from 2,211 in 2005 to 3,138 in 2008. Taking into account all costs―direct, indirect, and human―noise ranks first among all causal agents, with an average per-injury cost estimated at $154,406 a year. The average payouts in income replacement indemnities related to hand-arm vibration and whole-body vibration are generally much higher than the average cost of all injuries.

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Scientifics of this field

Scientific Partners and Collaborators

To carry out its work, the IRSST can count on an extensive network of experienced collaborators.

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