Citation

Fadier E, De la Garza C, Didelot A. Safety Sci. 2003; 41(9): 759-789.

Copyright

(Copyright © 2003, Elsevier Publishing)

DOI

unavailable

PMID

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Abstract

Analysis of industrial situations on a day-to-day basis shows deviations between that which is foreseen (at the design stage), that which is integrated into and installed on the production site, and that which takes place during operation. These deviations reflected the differences between the task and the activity, which is standard and known in ergonomics, but also between the planned nominal technical operation and the real operation including different situation recovery events, faults and failures (technical, human, organisational, etc.). The result of this real operation then may seriously affect production performance. However, it has been observed that this performance is preserved to a greater or lesser extent by the adaptive and palliative interventions of the operators. In specific cases, these interventions appear as "boundary activities" from the point of view of both the system performance and safety, but are nevertheless tolerated during use. We therefore attempted to understand the origin and characteristics of these activities, as well as their benefits and associated risks in a context marked by different forms of tolerance. Two categories of boundary activities were identified involving actors from different hierarchical levels and decision units, and production operators. Their detailed analysis involves the identification of a set of "boundary conditions tolerated by use". As described by Rasmussen [Safety Science, 27(2-3), (1997) 183], these boundary conditions tolerated by use mark a migration of the system towards less safe levels, reduce the room for manoeuvre of the operators, and engender risks for the socio-technical system. Knowledge of these conditions and their classification in relation to the boundary conditions tolerated by use stemming from the design and the internal boundary conditions tolerated by use of the firm should enable us to let these be taken into account by the designer so that they can be integrated, removed and/or accompanied by specific measures. Thus, consideration of boundary activities and boundary conditions tolerated by use during the design could allow the reference framework of the operational to be brought up to date. In addition, to be efficient, a prevention policy in a given company can benefit from the analysis of these phenomenons.