Accidents du travail et assemblage

Résumé

Cette étude compare l'influence, sur le risque qualitatif d'accidents,

de deux lignes d'assemblage de matériel de transport. L'organisation de la production de ces lignes diffère par le nombre de postes réduit sur l'une d'elles, ce qui intensifie la coactivité entre travailleurs à chaque phase du processus. Les 150 accidents avec perte de temps des assembleurs survenus sur ces deux lignes d'assemblage de véhicules routiers pendant trois ans sont regroupés en six classes homogènes, à partir d'une analyse multivariée de leurs caractéristiques. Aucun lien significatif n'est toutefois observé entre ces classes d'accidents et les lignes d'assemblage. Il est discuté que l'intensification de la coactivité puisse être un facteur de contribution à la fréquence des accidents mais non à leur type.

Abstract

The study was carried out in a Québec company that manufactures transportation equipment, and its goal was to compare the effect of two production organization strategies used on two different assembly Unes on the qualitative risk of accidents. For the same type of product, these lines differed essentially in the number of workstations and the average duration of a cycle by workstation. On the assembly line with fewer workstations, the number of parts to be assembled per workstation and the coactivity between workers are both higher. This line also had the highest accident frequency rate over the last year of the study.

To compare the accidents associated with each of the production lines, a series of characteristics of the 150 accidents with the time lost over three years was compiled and analyzed to answer the following question: "What are the most characteristic types of injuries to assemblers, and under what circumstances do they occur?" Then, the existence of a possible link between the types of accidents and the production line as well as between the types of accidents and the production phase was tested. Using multivariate analysis techniques, the assemblers' 150 accidents were summarized into six typical situations (classes): falls and impacts during displacements and during descents from vehicles; pain and muscular reactions caused by body movements; excessive efforts during the handling of parts or heavy equipment; pinches, blows and impacts associated with the handling of parts or tools; cuts to hands resulting from blows or rubbing; foreign bodies projected into the eyes. It was subsequently observed that there was no significant relationship between the types of accidents and the assembly line, nor between the types of accidents and the assembly phase.

It is understood that the results of this study cannot be assumed to apply to other companies in the sector concerned, since these are not results from a sectorially representative random sample. However, it seems that two observations have broader application regarding the work and the assembly tasks. The first is that accidents occur under circumstances, and have consequences, which can be typified. This observation invalidetes the hypothesis of the strictly random character of accidents and promotes the pinpointing of typical accident situations and problems for prevention. The second observation is that, for the same type of process, increased coactivity seems to be a determinant in the frequency of accidents, but not in their type. This does not mean that the extent of the coactivity by itself explains why accidents occur, but it suggests that it is a contributing factor in their occurrence.

As for the determinant factors revealed by the study for each type of accident, the results obtained and the available data do not allow solid conclusions. The question answered is the following, "What is happening, and under what work situations does it occur?" However, for determining "Why does this happen?" or "Why does it happen in this way?", at the very most, avenues may be opened. It is proposed that an attempt be made to answer these questions, considering the knowledge acquired, the potential number of workers affected, and the enduring nature of the tasks involved.