Optimisation des stratégies de production intégrant les aspects santé et sécurité au travail : cas de la transformation du granit

Abstract

This thesis presents work that aims to develop a production planning strategy to optimize costs while taking into account the occupational health and safety of employees. The manufacturing system studied is specialized in the transformation of granite. This process is responsible for the production of crystalline silica particles which, once inhaled, will cause the lung disease known as silicosis. In order to reduce exposure to these crystalline silica particles, manufacturers must implement necessary and effective prevention measures in their production systems. These measures represent an investment that will increase the total cost of production. That said, manufacturers must therefore review their production strategy to take into account the costs incurred by occupational health and safety. The first part of this study aims to integrate particulate matter reduction methods into the manufacturing system in order to establish an optimization strategy that takes into account the health of the operator exposed to silica particles emitted during machining. The system consists of a production machine to which two protective equipment is associated in order to reduce the concentration of crystalline silica below the regulatory limit. The whole system is subject to random breakdowns and repairs. The finished product obtained is a block of polished granite used in the manufacture of kitchen countertops. Unfortunately, the preventive measures adopted degrade over time, increasing the risk of exposure to crystalline silica particles. The second part of the work aims to integrate the degradation of dust abatement equipment as well as the occupational exposure limit constraint in the modelling of the manufacturing system. The system is described by a non-homogeneous Markovian process. A simultaneous research approach of production and preventive maintenance strategies is adopted in order to determine optimal production and replacement policies. Preventive maintenance aims to ensure the availability and effectiveness of preventive measures to meet the regulatory occupational exposure limit value. A study conducted by the IRSST shows that nearly a quarter of occupational accidents occur during maintenance activities. In order to reduce this number of accidents, the last part of this paper integrates padlocking into the modelling of the manufacturing system in order to ensure the safety of maintenance personnel. In order to eliminate any risk of premature start-ups during equipment interventions, we have considered the lockout as a step in its own right. The modelling was done using the non-homogeneous Markov chain. In all three parts of this paper, the optimal solution to the problem posed is achieved through the Hamilton-Jacobi-Bellman equations. A sensitivity analysis is then performed to confirm the results obtained.

Date	18 Aug 2020
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Jean-Pierre Kenné (Supervisor) & Victor Songmene (Co-supervisor)