23 research outputs found

    TUNNELING OPERATIONS, OCCUPATIONAL S&H AND ENVIRONMENTAL PROTECTION: A PREVENTION THROUGH DESIGN APPROACH

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    The study refers on the main results of a research work that has been carried out by the Safety and Health group of the Department of Environment, Land and Infrastructure engineering (DIATI) at the Politecnico di Torino, with reference to the substantial difference that exists between the case of an established absence of hazards due to the presence of noxious materials such asbestos, crystalline silica, in the rock mass to be excavated and the situations in which these minerals can be present. Since, when carcinogenic substances can be expected, corrective action following exposure or dispersion is clearly unacceptable, the presence of critical pollutants requires special preventive actions for the health of the workers and the muck which can introduce risks for the users (e.g., during mechanical processing involving feeding, crushing, milling, sizing and sorting operations) should not be considered for any reuse

    occupational safety and health in tunnelling in rocks formations potentially containing asbestos good practices for risk assessment and management

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    In tunnelling operations, Occupational Safety and Health (OS&H) and Environmental Protection of the areas close to the tunnel portal become even more critical in case of rock formations potentially containing asbestos, quartz, radioactive elements, etc. In order to limit the workers' exposure and the environmental impact becomes in these cases of paramount importance to preliminarily analyze and quantify the possible presence of the pollutants in the rock and, if necessary, to implement suitable measures to avoid/minimize their emission from the winning and mucking operations. However, in case of asbestos minerals, to obtain reliable results from the preliminary analysis is a challenging task, due to the complex patterns of occurrence of asbestos within the host rock. Consequently, the definition of special monitoring, alarm and control systems is essential during the tunnel excavation. The paper summarizes the results of a thorough study aimed at defining the most suitable monitoring techniques in uncertain situations and the residual criticalities, essentially due to the delay between the beginning of the pollutant release at the tunnel face and its detection. The final part of the work deals with the possible innovative prevention solutions suitable to minimize the previously mentioned delay and ensure the safety of the workers along the time necessary to stop the activities and evacuate the tunnel, on hold of the activation of a special "asbestos" organization

    Occupational Risk Assessment and Management in a System Approach: the Why and the How

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    Occupational Safety and Health - OS&H problems still remain an important criticality in many Statistical classification of economic activities in the European Community - NACE sectors in Italy. Even if the official Italian statistical data published by National Institute for Work Injury Insurance - Inail show some fluctuations in the yearly accident and health impairment rates, the 3 fatalities/day figure proves difficult to modify, and the number of traditional and new professional diseases remains very impressive (officially approximately 2/year deadly diseases). An extensive and in deep analysis of a number of case histories, carried out by means of an innovative technique (namely the Computer aided Cause Consequence for Prevention - CCCP approach) conclusively proved that this unacceptable scenario results from the following causes: a - Hazard Factors (situations, materials, substances, organization, reasonably predictable faults and errors in terms of Worst Credible Case - WCC, etc.) poor Identification, directly involving the absence of special prevention countermeasures; b – Poor Risk Assessment, involving under or overestimation of the seriousness of some safety problems, and hence a misguided organization of the prevention; c – Poor Risk Management, basically in terms of lacking internal/external audits of situations/operations vs the Risk Assessment results, lacking risk assessment revision in case of scenery modifications, and lacking conservation along the time of the safety measures resulting from the risk assessment. A side cause of the modest success of the actions aimed to modify the previously mentioned concerning occupational safety scenery is that the Heinrich approach (prevention can be implemented from information on the frequency of deviations from a correct working situation) is applied in a generalized way without discussion. But the Heinrich model is based on a “Person Approach” (the misconduct of victims or colleagues is the main cause of deviation, in spite of the obvious consideration that they and they only are in direct contact with the Hazard Factor). A Guideline based on a System Approach (the system approach concentrates on the conditions under which individuals work and tries to build defences to avert errors or mitigate their effects) was developed and successfully tested in a number different situations. The basic principia of the guideline, coherent with both the 89/391 EEC Directive and the OS&H in quality criteria, can be summarized in a 3E list: E1 - Engineering: Prevention through Design – PtD, focused to guarantee the highest safety level technically achievable through comparative analysis of alternative solutions, and the possible faults, human errors included (a formal demonstration is necessary); E2 - Education: information, education and training actions at every hierarchic level, derived from a Risk Assessment and Management specially conceived for the situation under exam; E3 - Enforcement: checking with internal/external audits the preservation through time of the safety level made possible by the PtD approach, and consideration of further improvements made available by the technical and epidemiology improvements. The paper discusses the previous aspects, and the Why and the How of the suggested Occupational Risk Assessment and Management technique in a System Approach

    A Prevention through Design Approach for the Environmental S&H Conditions and the Ventilation System at an Italian Underground Quarry

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    Even if the number of the Italian underground quarrying operations is steadily growing, in many cases the safety criticalities are somehow underestimated, in spite of the regulations D.Lgs. 81/08 and D.Lgs. 624/96, Italian enforcements of the former European Directives 89/391/EEC, 92/91/EEC and 92/104/EEC. Ventilation system is conceived to face very simplified requirements, whilst critical pollutants or emergency situations are not taken in due consideration. Asides, the ventilation system fault and availability analysis are seldom included in the project. The paper deals with the results of a research work started some years ago at an underground quarry exploited through drift sublevel based on drill and blast technique, to identify criteria suitable to grant effective safety and health -S&H- conditions for the workers operating in the underground in the Prevention through Design approach. Taken into account that the phases for an effective approach to the S&H problems in underground must follow a hierarchic method, in which the risk management should be faced from an effective hazard reduction to a minimum at the sources, and the ventilation should be considered only as a 4th level solution, the possibilities of control at the main pollution sources, i.e. the emission of pollutants due to the rock winning and mucking operations, have been examined. The residual risk was then faced with both the original underground and airways layout definition for a new exploitation development, based on technical and efficiency considerations, and on fire emergency computer simulations. Finally, the paper summarizes the results of an availability analysis of the ventilation system for normal operating conditions, and the emergencies management, on the basis of the results of Hazard Evaluation techniques, particularly Hazard and Operability Analysis and Fault Tree Analysis

    Environmental and occupational risk assessment and management in tunnelling and underground projects

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    Construction is one of Europe's biggest industries, providing jobs for nearly 13 million people. This represents nearly 8 % of the working population in Europe (only the public sector and retail employ more). It is also one of the most hazardous industries. More construction workers are killed, injured or suffer health impairments than in any other industry, and one of the most critical section in the construction sector is the underground construction. In particular the effect on workers' health is of serious concern. It is difficult to be precise about the true scale of the health problem, but all studies indicate the problem is huge. Every year many thousands of workers suffer from work related diseases. These include musculoskeletal disorders, noise induced hearing loss, skin diseases, and other diseases as a consequence of exposure to noxious substances. Additionally, the economic costs of poor safety and health are vast. One national study estimates that they typically account for up to 8.5% of a construction project's costs. The creation of underground space has significant impact on quality of life, working conditions, employment and environment. Innovative use of underground space will have a great impact. European Union policies include an upgrading of the Trans European road network (TREN), in order to improve interstate transport. This implies the construction of a significant number of tunnels (approx. 2100 km of tunnels will have to be constructed in Europe by the year 2030). Underground space will be increasingly used to alleviate pressing problems that will confront the European society in the next 20 years: traffic congestion, increasing urbanization (mega cities), lack of space and pollution of air and water. In Italy, the construction of rail and road tunnels through the Alps and the Apennines is very important in terms of connection and moreover, the requirements of transport systems, for civil use spaces and for innovative service networks is one of the reasons for the increase of underground works in urban areas more densely populated. The hydrogeological, geological, operational and environmental criticalities as met in such geological structures can nevertheless require increased care in the aforesaid situations. Projects under construction have further highlighted the importance of tunnels for the elimination of traditional surface, territorial and environmental constraints, but also for the necessary acquisition of consensus through the most comprehensive analysis and management of risks related to the effective fulfilment of such projects, in order both to meet the needs of the end users, and to preserve the dwellers and environmental safety conditions in terms of correct sustainable development. The most important changes in such a point of view occurred since the end of the last century, and suggest the need of a more effective and comprehensive approach to the concept of infrastructure. For this purpose it is nowadays required a horizontal approach, whereby different disciplines (technical, structural, architectural, environmental, financial and occupational safety) can interact and mutually stimulate in order to face the complex issues of underground works project. For these reasons, the designer's role becomes crucial to develop underground projects that respect a sustainable development approach; designer must know innovative and advanced technologies, materials and procedures, aimed at optimizing the economical, environmental and social development. Even the public client, responsible for government priorities and objectives of the intervention, is fundamental for the orientation of the operational choices of designers and builders of infrastructures. In fact, especially in the last decade, a number of guidelines and recommendations were issued by International, European and Italian authorities, the most effective of them based on the introduction of the prevention in the design phase and on a quality based risk management. The design and construction of underground operations require by the Designer and Contractor/s a decision making based on multiple factors (environmental, technological, etc.) that have specific characteristics and particular criticalities, far more than other industrial contexts, since they are often characterized by considerable uncertainty in their definition during the development of the project. In this context the Designer must identify the best option among several available solutions -which have different implications in terms of technical, operational, environmental and financial risks- while the Contractor/s must make a constant check on the preservation of design conditions, in order to control the validity of work and environmental safety requirements. Furthermore, for maintaining the correct safety conditions, it is of primary importance the application of Hazard Identification Techniques referring to different design solutions, and the definition of suitable confidence limits in order to provide the work manager with suitable instruments to constantly evaluate the yard situation and to avoid the overcoming of the aforesaid limits. The PhD research project has therefore to cover the most common criticalities encountered in tunnelling and underground works projects such as: - the presence of pollutants, and in particular carcinogenic minerals, such as, for example, the crystalline silica, which is recognized class A1 carcinogen (carcinogenic certain to humans) by the International Agency for Research on Cancer -IARC- since 1997 (and reaffirmed by the same organization in 2011) and the types of fibrous silicate included in the formal definition of asbestos, which there is no discussion on the ascription to the class A1; - the design and management of the construction yard: the presence of limited working spaces, the high concentration of high power machinery and the use of iterative work cycles, together with reduced time for the excavation, make mandatory the need to plan the interference among concomitant operations in order to prevent accident; - the control of the safety conditions: it is of primary importance the application of Hazard Identification Techniques referring to the choice of suitable confidence limits in order to make available for the work manager the instruments to constantly evaluate the yard situation to avoid the overcoming of the aforesaid limits and referring to the choice of equipment and procedures to minimize accidents at work. Taking into account the best available techniques, the principles of Quality and Prevention through Design approach, the PhD research has also set criteria for the identification and evaluation of the above mentioned criticalities in order to develop an expert system, finalized to make available an integrated system to optimize the economic, environmental and operational safety for the underground works activities in order to proceed rationally to choose the best solutio

    The Prevention through Design approach as a key tool in tunnelling operations and muck reuse

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    Purpose: on the basis of some case histories the problems are here discussed which can arise where a not exhaustive preliminary risk assessment is available, based on a quite detailed knowledge of the characteristics of the material to be excavated. Such problems cover occupational risks deriving from uncorrected selection of the tunnel driving technique and fittings layout, and environmental criticalities associated to unfeasible muck management and destination. The target of the present research work developed with reference to the tunneling operations, is to discuss an effective approach to the safety and health protection of the workers at the construction site, and to the environmental quality conditions in the surrounding areas. The latter should be referred to both the environmental protection, and to the reduction to a minimum of the environmental impact, this involving in particular the possibilities of reuse of the materials resulting from the tunnel driving operations. Methods: the research work is a part of a wide range study carried out by the Department of Environment, Land and Infrastructures Engineering (DIATI) of the Politecnico di Torino for the evaluation of the possibilities of the muck reuse. Nevertheless, this approach is possible only in the case of granted absence of hazards due to the presence in the rock mass to be excavated of noxious materials such asbestos, crystalline silica, etc., since, taken into account that in particular in the case of carcinogens, corrective action following exposure or dispersion is not acceptable, the presence of critical pollutants requires both special preventive actions for the workers health, and the impossibility of any reuse of the muck which could introduce risks for the users (e.g. during mechanical processing involving feeding, crushing, milling, sizing and sorting operations, etc.). Results: the first result is a discussion on the possibilities and techniques of a predictive assessment of the asbestos content in the rock, with special reference to the reliability of the achievable results. The second result is a discussion on the technical possibilities available to minimize the occupational risk where critical rock formations must be excavated. Finally, some considerations are provided on the often underestimated problem of the safety fittings availability, which can prove quite dramatic in the aforesaid critical situations. Conclusions: even if for both economic and environmental reasons the management of the material resulting from tunnel driving operations should be carefully evaluated, and any possible reuse considered, the very first step of such an analysis should be a very careful investigation on the possible content of critical minerals in the rocks to be excavated. In the case, no reuse is possible and a selection of the tunneling techniques and technologies suitable to the minimization of the occupational and environmental risks becomes of primary importance
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