Summary

In 2006, a survey of the safest practices relating to interventions on printing presses was carried out by the Association paritaire de santé et de sécurité du travail secteur imprimerie et activités connexes (ASP imprimerie, joint sector-based occupational health and safety association – printing and related activities sector) to establish a safe work procedure for these machines with several danger zones. From this, the ASP developed a fault tree tracing the combinations of causes resulting in a part of a worker's body being crushed in a printing press nip point. Consequently, this study focuses on the crushing hazards related to nip points on these machines.

Because of this fault tree, the ASP imprimerie developed a method for evaluating the hazards related to operations on these presses. Tested during visits to approximately 25 companies in the sector, the application of this methodology proved conclusive. Encouraged by this positive result, the ASP imprimerie made a request for expertise to the IRSST's research team to validate the fault tree's logic and comprehensiveness so that the ASP could then disseminate it, with a risk evaluation methodology and safe procedures for performing the four following operations:

1. Roller and blanket cleaning and washing,
2. Plate insertion and removal,
3. Blanket insertion and removal,
4. Paper threading.

The aim of this study was for the IRSST team to validate the initial fault tree's logic and comprehensiveness. This validation was conducted according to the following methodology:

1. Literature search to obtain more information about the concept of fault tree on printing presses, on the four operations studied, as well as on the standards and regulations in force applicable to printing presses;
2. Field validation: visits to eight printing presses to better understand the nip point hazards that the operator has to deal with during the four operations;
3. Completion and correction of the ASP fault tree, and verification of its structure so that corrections could be made to it;
4. Validation of the corrected fault tree with ASP imprimerie.

Application of this methodology generated the result of the study, namely a final fault tree with 300 combined causes, occupying 10 levels and that can explain the crushing of a part of a worker's body by one or more rollers/drums of the printing press during an operation. This tree is a useful tool because the causes can be visualized, and consequently, solutions can be found to avoid crushing accidents during an operation. The effectiveness of the solutions will depend on which category of causes is chosen for action. However, while this fault tree is not directly transposable to other machines with nip points and where the causes of crushing in a nip point need to be studied, it remains a very good starting model and could be adapted with minimum effort.