Development of a methodology for systematic analysis of risk reduction by protective measures in tyre production machinery

Abstract

2012 considers three factors to describe the likelihood of the occurrence of an incident scenario: the frequency of exposure of persons to the hazard, the probability of occurrence of the hazardous event and the technical and human possibilities of avoiding harm. The assessment of these factors can be quite controversial, especially when it concerns the amount of risk removable by protective measures: their mapping onto the risk factors is not always clear and this can lead to non-conservative over-estimations of the risk reduction. We propose a methodological framework compliant with ISO 12100 to systemically carry out repeatable risk analyses in support to the design of industrial machinery in which protective measures can be introduced to reduce risk. The methodology first proposes a scheme for identifying the contribution of PMs to the reduction of risk in a machinery under design. Then, the methodology classifies the protective measures and builds a clear mapping between these classes and the risk factors they impact on. This helps decision makers to identify the protective measures guaranteeing that the residual risk is acceptable. The methodology is applied to a real case study concerning a curing machine for tyre vulcanization, where it has proven to be beneficial for the clarity of the analysis and its repeatability. of the following three sub-attributes: (1) The frequency of exposure of persons to the hazard (Fr); in the risk matrix in Appendix A there are 5 exposure classes, which are assigned numerical values ranging from 1, in case of rare exposures with exposure time shorter than 10 min, to 5, for very frequent exposures. (2) The probability of occurrence of the hazardous event (Pr); this is expressed by an integer numerical value between 1, for negligible probability, and 5, in case of very high probabilities. (3) The technical and human possibilities of avoiding harm (Av); this attribute can take three possible values: 1, probable, 3, possible, and 5, impossible. Once the risk of a scenario is assessed, i.e., the severity of its consequences and the probability of its occurrence have been estimated, it is checked against a prefixed risk matrix (e.g., Appendix A ISO 12100, 2010; ISO/TR 14121-2, 2012) to establish whether it is acceptable or not. If not, some risk reduction measures are suggested by risk analysts

The Complex Approach in Risk Assessment and its Application at Machinery Safety Management

“…There are methods that are sufficient for enabling the risk assessment by mechanical hazard of a sharp machine edge, however, methods for risk assessment of hazardous substance leak (e.g. gas) from high-pressure pipeline, its initiation and subsequent fire of a "jet fire" type are different [26][27][28].…”

“…To reduce the consequences, tools, trying to reduce the extent of damage after hazardous event origination (e.g., sprinkling, extinguishing, alarm sirens) -the so-called reactive measures, are applied. The simplest method often applied in practice on the level of machinery risk assessment and work activities risk assessment is the so-called "risk matrix" [25,26,32,34,37,38]. It could be said that it is a framework method enabling identification of hazardous properties and hazards resulting from them, assessment of risks and their evaluation according to "own" rules considering determined acceptance rate of a reviewer (e.g.…”

“…The reason is obvious. By basic inevitable knowledge of EN ISO 12100 [14], [24][25][26] (by the way, the harmonized standard went through several alterations, from EN 292-1, 2, EN 1050, EN ISO 14121-1, EN ISO 12100-1, 2), there still happens to be incomprehension of the importance of individual steps of risk assessment ( Figure 1):…”

“…Then, estimation of probability and consequence follows, which requires selection of a suitable methodology for assignment of the probability and consequence parameters (e.g. risk matrix, risk graph, Fault tree analysis (FTA), Event tree analysis (ETA) etc., and this methodology may be in a form of qualitative, semi-quantitative or quantitative approaches [26,27]. The next important step of the logical procedure is expression of the relation of probability and consequence by a combination of their values, the so-called risk estimation (Step 3).…”

Methodology for Complex Efficiency Evaluation of Machinery Safety Measures in a Production Organization

“…The reason for this is obvious. Even with a basic knowledge of EN ISO 12100 [14,[24][25][26], the harmonized standards went through several alterations, from EN 292-1, 2, EN 1050, EN ISO 14121-1, to EN ISO 12100-1, 2), and there still happens to be incomprehension of the importance of the individual steps of risk assessment (Figure 1):…”