La valutazione del livello di integrità dei sistemi di protezione delle macchine, dall'analisi dei rischi ai dati affidabilistici

Through the application of several different methods of analysis it was showed definitely that a risk analysis conducted on an industrial machine, taking into account the human factor from the beginning, has a significant impact in the assignment of SIL to all Safety Integrity Function (SIF). The same phenomenon occurs in the verification and computation of the performance level for each device of the press. Comparing these methods and the results obtained through the development of a further case study carried out during the Spring at Trinity College of Dublin it was possible to define a useful logical model of analysis to describe and assess the risks related to human-interface and usable to verify and calculate the safety integrity level of the safety functions of the machine. This methodology is a combination between the Integrated Dynamic Decision Analysis (IDDA) and the Technique for Human Error Rate Prediction (THERP). The application of the Decision Analysis has been made possible through a careful reconstruction of the operating procedure regarding the use of the press applying an using an ad hoc Failure Mode and Effects Analysis (FMEA) template. The system of the study was described by IDDA in a random sequence of events where the given values of probability derived from the THERP model for human error and from the method of calculation set out by the standard technique (EN IEC 62061) for dangerous failures of safety devices. This integrated approach has allowed to take into account human factors with greater detail and in a quantitative way describing where and why the operator can cheat or by-pass the safety system, unlike other methods of risk assessment where you could only identify where the man-machine interface should be analyzed in dept

Human Factors Issues and the Risk of High Voltage Equipment: Are Standards Sufficient to Ensure Safety by Design?

High voltage equipment is mostly designed according to technically prescriptive standards requirements based on electrical engineering safety principles. However a more risk-based approach to standards and regulation may be advisable to enable designer and user to take an active role in establishing that their installation is inherently safe. The use of Gas Insulated Switchgear (GIS) for instance is enabling the new substation to be housed indoors and condensed into around one quarter of the space. The manufacturers argue that design improvements in GIS make it virtually “maintenance free”, comply with all the relevant standards. However some of these improvements have implications for the operators that need to be taken into account. Commissioning, operational checks and inspections and the occasional maintenance interventions are activities during which the technicians need to interface with the equipment, the issues regarding the interfaces provided have been analysed to identify their relevance in the overall risk assessment of the equipment. The paper reports about a study aimed at verifying through a risk analysis the impacts that the issues related to deficit in ergonomic design may present for the overall availability and safety of the plant. Those issues are not tackled in the technical standards and/or designers current practice

Erratum to: Hospitalizations for pertussis in Italy, 1999–2009: analysis of the hospital discharge database

n/

Activities of extracts and compounds from Spiranthera odoratissima St. Hil. (Rutaceae) in leaf-cutting ants and their symbiotic fungus

The study of the Spiranthera odoratissima St. Hil (Rutaceae) branches extracts led to the isolation of the furoquinoline (dictamine, gamma-fagarine and skimmianine) and 2-arylquinoli-4-one (1-methyl-2-phenylquinolin-4-one) alkaloids and limonoids (limonexic acid and limonin). The compounds 1-methyl-2-phenylquinolin-4-one and limonexic acid were isolated for the first time from the Spiranthera. These furoquinoline and 2-arylquinoli-4-one alkaloids and limonoids showed insecticidal and/or fungicidal activity in the nest of the Atta sexdens rubropilosa

Human factor analysis embedded in risk assessment of industrial machines: Effects on the safety integrity level

The study proposed in this paper consists of devising a method to account qualitatively and quantitatively for the human factor in verifying the Integrity Level of Safety system (SIL) assigned to the machinery. It is called "operational SIL", which may differ from the design SIL, due to the impact of human and organizational factors (H&OF) in the operational phase. There are two crucial aspects related to modelling man-machine interaction in Quantitative Risk Analysis (QRA) context: 1. the need to insert human interaction in the logical model of QRAs techniques; 2. the quantification of effect of human factors. During the study an Operability Analysis, which is usually known with the acronym HAZOP (Hazard and Operability studies) was initially used to support the assessment, but with some added features that enable one to accommodate systematically H&OF into the process called Integrated Recursive Operability Analysis framework (IROA). This first attempt to apply IROA methodology showed that this type of analysis highlights the position where in depth human factor analysis must be carried out. Once the point is identified in which the human erroneous action may occur it will be necessary to include the study of human factors and the assessment human error probability (HEP). Our efforts are aimed at defining an improved methodological framework encompassing the integration of H&OF into safety analysis by means of quantitative risk assessment schemes. In order to do that the adopted tool is the Integrated Dynamic Decision Analysis (IDDA). This tool allows modelling the logic of a complex system; it provides a representation of all the possible alternative states into which the system could evolve, as a real logical and temporal sequence of events. The proposed model is designed precisely with the aim of transferring the IDDA philosophy to the in-depth study of the deviations which may occur during human implementation of operational procedures. IDDA developed on the basis of a Task Analysis (TA) could allow to obtain a detailed quantitative analysis of human factors directly during the same risk assessment. Starting from the analysis of a technological system through IDDA it is possible to integrate in the logical model a task analysis describing where and why the operator can cheat or by-pass the safety system thus including in the assessment explicitly the human factors that allow evaluating the operational SI

Human Factor Analysis Embedded in Risk Assessment of Industrial Machines: Effects on the Safety Integrity Level

The study consists in devising a method to account qualitatively and quantitatively for the human factor in verifying the Safety Integrity Level (SIL) assigned to machinery. Two crucial aspects have to be taken into account modelling man-machine interaction in Quantitative Risk Analysis (QRA): 1. The need to include the human interaction in the logical model of QRAs techniques; 2. The quantification of the effect of human factors. The efforts were thus aimed at defining an improved methodological framework encompassing the integration of Human and Organisational Factors (H&OF) into safety analysis by means of quantitative risk assessment schemes. In the end, the Integrated Dynamic Decision Analysis (IDDA) was adopted, integrated to Task Analysis. This tool allows modelling the logic of a complex system; it provides a representation of all the possible alternative states into which the system could evolve as a real logical and temporal sequence of events. The proposed model is designed with the aim of transferring the IDDA philosophy to the in-depth study of the deviations that may occur during human implementation of operational procedures and to analyse their effects on system reliability

Amphibia, Anura, Hylidae, Itapotihyla langsdorffii (Duméril and Bibron, 1841): correction of older record and distribution extention

Non

Human Factor Analysis Embedded in Risk Assessment of Industrial Machines: Effects on the Safety Integrity Level

The study consists in devising a method to account qualitatively and quantitatively for the human factor in verifying the Safety Integrity Level (SIL) assigned to machinery. Two crucial aspects have to be taken into account modelling man-machine interaction in Quantitative Risk Analysis (QRA): 1. The need to include the human interaction in the logical model of QRAs techniques; 2. The quantification of the effect of human factors. The efforts were thus aimed at defining an improved methodological framework encompassing the integration of Human and Organisational Factors (H&OF) into safety analysis by means of quantitative risk assessment schemes. In the end, the Integrated Dynamic Decision Analysis (IDDA) was adopted, integrated to Task Analysis. This tool allows modelling the logic of a complex system; it provides a representation of all the possible alternative states into which the system could evolve as a real logical and temporal sequence of events. The proposed model is designed with the aim of transferring the IDDA philosophy to the in-depth study of the deviations that may occur during human implementation of operational procedures and to analyse their effects on system reliability

Human factors issues and the risk of high voltage equipment: Are standards sufficient to ensure safety by design?

High voltage equipment is mostly designed according to technically prescriptive standards requirements based on electrical engineering safety principles. However a more risk-based approach to standards and regulation may be advisable to enable designer and user to take an active role in establishing that their installation is inherently safe. The use of Gas Insulated Switchgear (GIS) for instance is enabling the new substation to be housed indoors and condensed into around one quarter of the space. The manufacturers argue that design improvements in GIS make it virtually "maintenance free", comply with all the relevant standards. However some of these improvements have implications for the operators that need to be taken into account. Commissioning, operational checks and inspections and the occasional maintenance interventions are activities during which the technicians need to interface with the equipment, the issues regarding the interfaces provided have been analysed to identify their relevance in the overall risk assessment of the equipment. The paper reports about a study aimed at verifying through a risk analysis the impacts that the issues related to deficit in ergonomic design may present for the overall availability and safety of the plant. Those issues are not tackled in the technical standards and/or designers current practice

Application of standard IEC 62061 to a case study on hydraulic press

The standard IEC 62061 is a machine sector specification within the framework of IEC 61508. It is intended to facilitate the specification of the performance of safety-related electrical control systems in relation to the significant hazards of machines. Compliance with this standard provides one with means of conformity with the specified essential requirements given in Annex I of the EC Directive 2006/42/EC. This paper reports a case study on a press where an accident occurred. Through an appropriate risk analysis and reliability data a priority of interventions has been defined to reduce risks in the specific machine under investigation. The main target of the analysis was to test the applicability of most recent generation standards, that are not yet fully acquired by different industries, and to verify their effectiveness. A risk assessment was performed in order to verify the compliance with the essential requirements of the Machinery Directive 2006/42/EC. A risk assessment should include a look at each functional part in turn, making sure that every mode of operation and all phases of use are properly considered, including the human-machine interaction in relation to the identified functions or functional parts. For this reason the Hazard Identification approach (HazID) was chosen to investigate the criticalities of the bending tool. The HazId analysis was used as a support for the determination of the required Safety Integrity Level (SIL) of the safety-related functions that must be realized by a safety-related system. Once SIL has been assigned to Safety-Related Electrical Control System (SRECS), it was fundamental to calculate the SIL associated to that component and to verify if it is equal to the previously assigned SIL. This case study has shown that the performance of a safety instrumented system in the operational phase is influenced by many factors; not only by the system design and the related testing and maintenance strategies, but also by the operating conditions in the wider socio-technical system. For this reason it is important to account for the human factor in assigning integrity levels of safety systems (SIL) to the identified security functions