Calculating the reliability of a zero-energy state system

Type de document

Articles dans des actes de congrès

Année

2024

Langue

Anglais

Directeurs de la publication

Malm, Timo

Titre des actes

SIAS 2024 Proceedings: Safety of Industrial Automated Systems, SIAS 2024, June 12-13, 2024, Tampere, Finland

Maison d’édition

FSA

Résumé

In Canada and other industrialized countries, workers who are required to carry out tasks in the hazardous zone of a machine when performing repairs, maintenance or unjamming activities must follow lockout procedures, unless safe alternative methods exist and can be applied. In Quebec the occupational health and safety regulation has been updated recently and several articles have been added on lockout procedures. That regulation allows for alternative control methods in addition to the traditional lockout/tagout, as long as the risk assessment deems the residual risk level to be acceptable. In Canada the CSA Z460 standard in the control of hazardous energies is viewed as a reference in the area. Lockout procedures have been extended to the construction sector for the control of hazardous energies as well. The lockout procedure consists of the following steps: stopping the equipment, isolating the energies, applying individual locks, dissipating residual energies, and verifying the absence of energies. Lockout procedures require lockout devices as well as training and audits. An important step in the lockout procedure is the verification step. Workers often neglect that step for various reasons. This article focuses on the use of dedicated safety electronic systems as an alternative to achieving a zero-energy state. These systems, rather than eliminating energy, control it to ensure workers’ safety. They are characterized by their reliability and typically involve safeguards such as interlocking devices, safety scanners, light curtains, and other safety mechanisms, during operational tasks. The article also introduces a method for calculating the reliability of these zero-energy-state system, based on the ISO 13849 standard. This method aims to help businesses comply with both the local regulation and the CSA Z460 standard. It builds upon the work of Poisson et al. (2016) [1], who calculated a zero-energy-state system in scenarios involving complex energy return recuperation systems. This innovative approach could potentially replace the need for voltage testing or machine startups following a lockout procedure. This development is particularly relevant given the increased complexity of modern machinery and the challenges in ensuring that no other energy sources that could harm workers are present post-lockout. This approach could significantly change how businesses ensure worker safety and regulatory compliance.

Mots-clés

Cadenassage, Locking for safety, Dispositif de protection, Safety device

Numéro de projet IRSST

n/a

Link to Full Text

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