- Email: [email protected]
Computer image generation for job simulation: An effective approach to occupational Risk Analysis
Safety Science 48 (2010) 508–516
Contents lists available at ScienceDirect
Safety Science journal homepage: www.elsevier.com/locate/ssci
Computer image generation for job simulation: An effective approach to occupational Risk Analysis Mario Patrucco a, Daniele Bersano a, Caterina Cigna a,*, Federico Fissore b a b
DITAG Politecnico di Torino, Cso Duca Abruzzi 24, 10124 Torino, Italy Visualink, Pzza Castello 2, 10040 Osasio (TO), Italy
a r t i c l e
i n f o
Article history: Received 24 February 2009 Received in revised form 23 December 2009 Accepted 30 December 2009
Keywords: Job Safety Analysis Risk Analysis Prevention Computer simulation
a b s t r a c t The paper deals with the general approach and features of the computer image generation for job simulation (CIGJS) method, as specially developed to support the Job Safety Analysis (JSA) technique. Starting from some general considerations on the occupational safety and health statistical data collection in Italy, when compared to US methodology, the paper provides an overview of the CIGJS method, developed to improve the effectiveness and usability of the traditional JSA. A case study is discussed in order to highlight how CIGJS makes the use of the JSA technique possible also at the design stage (this being fundamental according to a Prevention through Design approach), and allows to control the effectiveness of the adopted countermeasures. The application of the method complies with the basic European Directives requirements both on workers’ safety and health and on machinery analysis. Furthermore, CIGJS may substantially aid workers’ education and training, to the point of being a possible simulation-training device. Ó 2010 Elsevier Ltd. All rights reserved.
1. Introduction The Job Safety Analysis (JSA) technique – based on the common Risk Analysis approach consisting in a thorough analysis of the various sub-tasks in which a macro working task may be logically subdivided – is a widely used and powerful tool to effectively identify the possible hazards associated with each working sub-operation, together with the respective time duration, so that, step by step, the hazards involved, the associated risk, and the practically applicable technical and procedural countermeasures may be directly identified, evaluated both in terms of effectiveness and cost, and finally developed. The great variety of data drawn from different industry sectors has always been a bar to a widespread application of the JSA technique; moreover, for a proactive Risk Analysis of new tasks or work conditions, JSA alone may not be the most suitable solution. Providing a realistic simulation of the actual work situation, computer image generation for job simulation (CIGJS) can rather successfully contribute to the analysis, improving the effectiveness and usability of the conventional JSA in routine work situations, and making the use of JSA possible also at the design stage, since a virtually infinite number of different options in terms of area * Corresponding author. Address: DITAG Politecnico – Corso Duca degli Abruzzi, 24, 10129 Torino, Italy. Tel.: +39 011 090 7733; fax: +39 011 090 7699. E-mail addresses: [email protected], [email protected] (C. Cigna). 0925-7535/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.ssci.2009.12.025
layout, working conditions and procedures may be compared in detail. The critical rates of occupational injuries and fatalities, typical of some industry sectors, need to be faced with suitable Risk Analysis techniques, therefore the use of JSA + CIGJS method may be an important improvement in order to minimize the risk conditions at workplaces. Finally, further development of the CIGJS method are expected in the field of workers’ education and training, following the successful application of computer-based simulations to several educational scenarios in the fields of medicine, engineering, computer science, environmental education, and business (Mujber et al., 2004; Pfahl et al., 2004; Ioannidou et al., 2006; Lainema and Nurmi, 2006; Passman et al., 2007; Gettman et al., 2008). 1.1. Industrial safety and health situation at present Official data from INAIL (Italian Workers’ Compensation Authority) show a situation of three fatal accidents per day1 (INAIL, 2008); it is clear that the only way to reduce such an unacceptable rate is to carry out an effective Risk Analysis and undertake proactive preventive actions based thereon. In fact, it should be known that ‘‘one of the best ways to prevent and control occupational injuries,
1
Official INAIL data of fatal injuries: 1207 fatalities in 2007.
M. Patrucco et al. / Safety Science 48 (2010) 508–516
509
Fig. 1. Data drawn from direct in-depth analysis of fatal accidents causes.
illnesses and fatalities is to ‘design out’ or minimize hazards and risks early in the design process” (Howard, 2008). The Safety and Health (S&H) of workers at the workplace is a concerned problem in all countries, not only in Italy, as exemplified by the data listed in Tables 1 and 2. Besides territorial differences that obviously affect the data comparison, the use of a different methodological approach has resulted in a obstacle to the statistical analysis of occupational S&H data in USA and Italy. In fact, Italian rates of fatal injuries consider a 3-year period and refer to a base of 1000 workers employed in the industry sector, while the US rates are annual and refer to a base of 100,000 workers. Referring to the following tables, the Authors had to scale US rates in order to obtain comparable values, losing details of the data (on the other hand, scaling of Italian rates would have led to greater error). From both the reported statistics it is clear that the construction sector represents the most critical industry sector in terms of number of fatalities, as already discussed by many authors (Gambatese and Hinze, 1999; Behm, 2008). In the USA – even if the highest rate pertains to agriculture, forestry, fishing, and hunting, followed by mining – as far as the number of fatalities is concerned, construction exceeds more than three times the average value and lies above the following sector (transportation and warehousing) by 30%. The Italian situation is even clearer, with the construction sector fatalities representing the first cause of death among workers, both taking into account the rate (more than three times higher than the average) and the number (four times higher than the average). Another sector that appears to be critical is mining, which – despite a number of fatalities lower than the average – shows the second rate value on both charts. The differences between the two countries are not negligible (e.g. in terms of dimension, mined materials, techniques, and technologies); however, this sector is particularly noteworthy and general considerations can be made. Based on the Authors’ research group experience (Pellegrino, 2008), basically focused on construction and mining activities, the main causes of industrial work-related accidents in Italy have been studied, in order to identify the critical aspects at the design stage and to establish a suitable hierarchical list of preventive interventions (the main results being summarized in Fig. 1).
This being the situation, the main steps to face the problem in a correct way should be: An in-depth analysis of past events (e.g. a collection of data on standard violations, real machinery conditions, use procedures, etc.); a proactive approach to foresee the critical situations in detail and immediately correct any safety flaws. 1.2. Criticality ranking It is demonstrable that a detailed analysis of occurred events is essential to collect exhaustive information about the causes lying at the very core of the event, and hence to identify properly the corrective actions to adopt. A significant example of such an approach may be drawn from OSHA data collection, wherein specific standard violation is provided.2 Unfortunately, in Italy no official records are available on the violations of occupational S&H standards and laws. Therefore, no general considerations useful for an effective preventive action may be drawn on this basis for now. Some attempts were developed in the past by the Authors’ research group for a number of case studies related to major accidents, e.g. loading and haulage of machinery in construction sites (Camisassi et al., 2004), the target of the research work being the identification of the most critical machinery type. The approach led to a numerical evaluation of the criticality factor KR, defined as
KR ¼
no: of recorded fatalities=no: of machines hours of use shift=shift duration
whose meaning may be summarized as follows: the smaller the number of used machines of the considered type and the smaller the percentage of work shift during which the machines are used, 2 The literal meaning of ‘‘safety” being ‘‘lack of risk”, a true zero-risk condition is not always achievable unless by suppressing the risk-causing activity: this leads to the culture of acceptable risk, where the limit value may be reached basically by meeting a set of technical standards and S&H requirements.More stringent requirements, may or may not be technologically feasible at a given time: in the interest of workers’ S&H, the risks vs. benefits of the possible alternatives must be carefully considered.
510
M. Patrucco et al. / Safety Science 48 (2010) 508–516
Definition: KR = [n° recorded fatalities / n° machines] / [hours of use shift / shift duration] Experimental data n° recorded fatalities / n° machines
hours of use shift / shift duration
2.5
0.8 0.7
2
0.6 1.5
0.5 0.4
1
0.3 0.2
0.5
0.1 0 excavator
off highway truck
0
rubber tyred loader
excavator
off highway truck
rubber tyred loader
Final result KR values for some widely used machines 6 5 4 3 2 1 0 excavator
off highway truck
rubber tyred loader
Fig. 2. Criticality factor KR for loading and haulage of machinery in construction sites.
the higher the criticality factor KR (see Fig. 2) (Camisassi et al., 2006). Obviously, the work analysis based on a set of non-homogeneous or incomplete data can only lead to partial results, as may be drawn from a series of similar experiences (e.g. NOHSC, 2004). Where new working situations are introduced, JSA + CIGJS makes the analysis of the safety criticalities at the first design stage possible, with the aim of carrying into evidence the S&H problems and the necessary control measures, to support properly the Hazard Identification and Risk Analysis and Management frames, contributing effectively to a Prevention through Design (PtD – NIOSH) approach. 2. The basic approach of the proposed Risk Analysis technique The main results achieved by the Authors with the target of providing well-tested guidelines for an effective approach to the Risk Analysis and Management were presented during the S.H.C.M.O.E.I – Safety and Health Commission for the Mining and Other Extractive Industries – Workshop on Risk Assessment, in 1996 (Faina et al., 1996) and were published in the Official Gazette of Lombardia Region (Regione Lombardia, 2002). It must be underlined that, even if originally developed for mining and earthmoving activities, the approach was successfully adopted in a number of different industrial typologies. The main features of the quoted approach may be described as in the following considerations: a correct Risk Analysis may only be performed for situations accomplishing the requirements of standards and laws; preliminary and constant Risk Analysis and control are needed (e.g. site characteristics, special countermeasures, basic safety structures, fitting and organization, emergency and rescue teams), in a continuous improvement approach; the assessment of the contact factor (evaluated as the percentage of time/shift during which there is exposure to a certain risk
factor) and the identification and management of interferences are fundamental tasks for the correct evaluation of the actual risk conditions; the use of widely recognized, well-tested and suitable Risk Analysis techniques is of paramount importance, both for safety analysis and control of each working activity (e.g. through JSA) and for failure analysis and control of hazardous plants or operations (e.g. HAZOP and FTA). The Job Safety Analysis (JSA) technique – based on the common Risk Analysis approach consisting in an in-depth analysis of the various sub-tasks in which a macro working task may be logically subdivided – is a widely used and powerful tool to identify effectively the possible hazards, together with the time duration related to each working sub-operation, as stated also by OSHA (‘‘One of the best ways to determine and establish proper work procedures is to conduct a Job Hazard Analysis”) (Chao and Henshaw, 2002). The JSA technique focuses on the relationship among the worker, the task, the tools, and the work environment, so that, step by step, the hazards involved, the associated risk, and the practically applicable technical and procedural countermeasures may be directly identified, evaluated in terms of effectiveness and cost, and finally put in effect – as shown in Fig. 3 – to eliminate or reduce the risk to an acceptable level. Further, Risk Analysis is the basis on which setting up a correct, suitable, and effective Risk Assessment, this being – according to the European Community definition – ‘‘a systematic examination of all aspects of the work undertaken to consider what could cause injury or harm, whether the hazards could be eliminated, and if not what preventive or protective measures are, or should be, in place to control the risks”. Risk Analysis techniques are the tools to identify hazards and workers at potential risk from those hazards, finally providing a quantification of the risk involved. With these data, the management will then apply the hierarchy of control measures (elimination, substitution, reduction at the source, collective protection, PPE).
M. Patrucco et al. / Safety Science 48 (2010) 508–516
511
Fig. 3. JSA procedure for a proactive prevention approach.
Unfortunately, in its traditional approach, the JSA technique has some not negligible intrinsic limits, which reduce the possibility of use in some particular situations: the analysis of possible interferences (e.g. between machines and people in narrow areas) is relatively complex and time consuming; therefore, as a matter of fact, only one operation at a time shall be considered; it should be noted that only the actual operating situations may be considered, since when a new task requires to be organized correctly in terms of job efficiency and workers S&H – this being e.g. the case of special maintenance or emergency operations – the results are remarkably less reliable, due to the difficulties in defining the scenarios not already in existence. A substantial improvement in the analysis capabilities both in routine conditions and in the aforesaid difficult situations was successfully achieved thanks to the introduction, in the traditional JSA technique, of the computer image generation for job simulation (CIGJS) approach, which is based on virtual images, animation, and 3D interactive environment, as specially developed for JSA purposes. Therefore, CIGJS should be considered as a helpful tool to support the application of the JSA technique, in the eyes of a wider Risk Assessment. In fact, CIGJS permits an intuitive and complete Hazard Identification and an interference definition, either between worker/machinery or worker/worker. However, a preliminary subdivision of the working task by means of JSA is essential. The choice of the JSA technique among other Risk Analysis techniques is due to the possibility of focusing on the sub-tasks, the related hazards, and the adopted (or foreseen) risk control measures. At present, there exist many validated and up-to-date methods (often based on numerical simulation, e.g. Monte Carlo methods, Fuzzy Logic) suitable for the Risk Analysis. Generally, they are developed for major accident scenarios, and mainly devoted to the analysis of very complex systems and situations (Konstandinidou et al., 2006; Zio et al., 2006). These techniques, formerly developed for chemical or nuclear plants, show some common characteristics: they need a very detailed description of plants, systems, and machinery; they refer to system faults or human errors; and finally they are aimed at retrieving information about collective protection of workers or communities (Salvi et al., 2005). Large, detailed, and representative statistical data are fundamental as input and dramatically affect the results, the final aim of the methods being the forecasting of accident scenarios (Zheng and Liu, 2009). Unfortunately, in a series of real industrial situations (as construction sites or extractive activities), some of the described requirements cannot be applied; for instance, activities and layout features can considerably vary in different quarry plants and the statistical basis becomes, if present, inadequate to provide useful data.
Since the aforesaid methodologies appear to be too complex or over-dimensioned for ‘‘normal” industrial sectors, the JSA + CIGJS approach is proposed as a suitable option. 3. Computer image generation for job simulation (CIGJS) supporting Job Safety Analysis 3.1. The software The computer image generation for job simulation has been set up in cooperation with Visualink, a multimedia, and web design agency. After a deep study of the project and a comparison of the different state-of-the-art products, the agency decided to adopt Lightwave 3DÒ. This software is widely used to create images, animations, and simulations, allowing the user to work at different levels of complexity from basic situations – which obviously need a relatively short time for development – to complex simulations, as for instance epithelial tissues, physical and fluid dynamics laws, etc. With a wide community of users that contributes to the development of specific additional features, such as architectural, geological, mechanical, and medical items, Lightwave 3DÒ is globally considered as one of the most versatile graphic software products on the market. 3.2. Software characteristics When a scenario has to be simulated, it is possible to create a 3D environment using photographs or planimetries from CAD files, an orthogonal projection finally producing solid objects. In order to reach a photo-realistic effect once the object has been created, the surfaces are imported from photographs and ‘‘pasted” on the object. The last stage of creation of the environment is the positioning of the objects in a virtual place where lights, cameras, and animations may be set up for a future use. Now, the 3D environment is ready for the rendering of images and animations to create 3D realistic movies, or for the exportation, allowing the final user to operate in a real-time interaction. Once the environment is completed, various elements may be added, such as doors, joints, mechanical arms, or natural features (water, gases, etc.). This is particularly important for the target of the research work herein described, because it permits to take into account the features and the behavior of work environment, machinery, etc., in a realistic manner. 3.3. Potentiality Every object created may be modified afterward, in order to improve the photo-realistic output or the proportions in relation with the environment. If the object cannot be modified, it may be replaced by a new one ad hoc programmed.
512
M. Patrucco et al. / Safety Science 48 (2010) 508–516
In the example herein proposed, the man responds to the anthropometric parameters according to the international standards (UNI EN ISO 7250:2000 – Basic human body measurements for technological design, UNI EN 547-2 1998 Human body measurements – principles for determining the dimensions required for access openings and UNI EN 547-3 1998 Human body measurements – anthropometric data). It is also possible to modify the worker’s anthropometric parameters while maintaining the same sequence of actions aimed at achieving the final target. The software allows the animation of the character to be bound as in the real world, building a skeleton inside the body and limiting the articulations movements permitted, while skin and muscular behavior are also simulated. This is obtained through both the Inverse Kinematics command, based on mechanics, and the Motion Capture mode, a stereophotogrammetric system based on ‘‘capturing” the real movements of a person wearing a black suit with lights on the joints in a cameras-surrounded environment. The recorded data are mapped to create a 3D model performing the same actions as the observed subject (see Figs. 4 and 5). Every object can then be bound by itself or by other objects in the environment and, after implementing physical laws, collisions, weights, forces, frictions and all kinds of interactions between people and/or machineries may be simulated. Because of its versatility and efficiency, the software is used in the film-making industry, wherein a lot of special effects are asked to interact with the characters. These features may be useful to simulate the actions of a real worker in a real scenario, for instance, with the aim to investigate the possibility of a contact with harmful parts of machinery or equipment, or to avoid overextension, etc.
3.4. Limits and criticalities Virtually, the software has no defined limits, and the potential is basically immeasurable. Obviously, the basic version presents a number of limits, but through plug-ins and customizable scripts, these can be overcome. The software is created so that you can build a virtual reality which is as ‘‘authentic” as possible, while
Fig. 4. Graphical model for human body, developed to be strictly linked to anthropometric parameters.
reproducing rules considering measurements of length (in meters or feet), weight (in kilograms or pounds), angles (in radians or degrees), temperatures (in Celsius or Fahrenheit), etc. The real limit lies in the possibility of modifying the project only within the software, before generating the final support (a static image, a movie, a 3D interactive environment, etc.), that would otherwise need the generation of new media. 3.5. Opportunities It is important to remember that the European regulation states that the Employer shall provide all information, instruction, training, and supervision that may be necessary to ensure the health, safety, and welfare of the workers and other persons while at work (Council Directive 89/391/EEC). Also, great consideration is given to the consultation and participation of workers, cornerstone in determining safety and health concerns and the subsequent suitable safety measures. In the past, some experimental work on the use of virtual environments for construction workers education and training were conceived (Arcangeli et al., 1999; Assfalg et al., 2002) and proved to be effective, demonstrating that ‘‘using the system would give the user a positive impression about the suitability of 3D graphics as a training system”. Other positive experiences can be found in the field of InfoErgonomics (Imai et al., 2002), wherein aspects like comfort of the workers and optimal human/machine co-existence are taken into account. The authors of this research stated that ‘‘modeling human beings and creating virtual employees via computer graphics still has a very limited use, because of the human body’s high complexity and the limits imposed by the computer techniques”. Recent developments in computer graphics software allowed the Authors to develop the proposed method, using more complex and realistic models for the description of human body and workers’ skills. Therefore, with the described software it was possible to obtain a realistic simulation of a real workplace and of the tasks actually performed by the workers, so that the new JSA + CIGJS approach permits easier, faster, and much more intuitive analysis of the hazards potentially present in each sub-task, and their effective control. The workers themselves play an important role in defining the simulation parameters, thus actively contributing to the health and safety of the specific workplace they are already working in or they will operate in. If developed for educational purposes, the method can provide a simulation-training device, with the advantage of a 3D interface with near real-world representation, for applying learning-bydoing and case-based reasoning approaches. In case of routine operations, each sub-task may now be reproduced on a computer display – again and again where necessary – and analyzed to identify the possible safety criticalities, thus reducing the number of in-field operations.3 The attainable accuracy is relatively high, since site and machinery data may be obtained from CAD files reproducing the area, while the worker movements and behavior may be evaluated from digital cameras or video recordings; the possible control alternatives themselves may be easily analyzed and discussed to identify the safest and most effective solution. Moreover, the possibility of ‘‘rewinding” the CIGJS images may be helpful to analyze multiple operations, the involved interference problems being easily highlighted, thus simplifying the
3 Nevertheless, it must be strongly underlined that at least one direct task observation by the Risk Analysts is in any case necessary, together with the discussion of the criticalities identified in cooperation with the workers in order to get essential info on modus operandi, on hidden problems and on the feasible control measures. As a consequence, video recordings cannot replace exhaustively direct observation, but should be considered only as a helpful tool for the CIGJS.
513
M. Patrucco et al. / Safety Science 48 (2010) 508–516
Fig. 5. General view of the plant as resulting from the simulation model.
approach to different analysis techniques such as Functional Space Analysis (Alfaro Degan and Pinzari, 2001). If used with the aim of studying the safety conditions for new plants or in case of improvement/renewal of the existing ones, JSA + CIGJS could effectively represent a powerful means to draw attention to critical situations, allowing the identification of the suitable solutions in accordance with the correct hierarchy of controls (Manuele, 1997), directly at the design stage (as stated in the basics of NIOSH PtD program).
4. A case study As described in Tables 1 and 2, construction and mining sectors proved to be critical in terms of fatalities: official data show that these industrial sectors are at the top of the criticality ranking, in terms of number and accident rates. Moreover, falls represent a statistically significant cause of fatality in the aforesaid activities (US Bureau of Labor Statistics, 2008, and ISPESL et al., 2006), even if a number of regulatory requirements, technical solutions, and procedures exist to protect the workers. This being the scenario, the Authors decided to apply the JSA + CIGJS to an existing pneumatic transportation system located in a crushing plant for extractive activities, where a simple operation, consisting in the regulation of a valve on top of a 15 m silo, was found to be critical. First of all, the virtual environment was set up based on CAD files and pictures taken during a preliminary direct inspection; particular care was dedicated to the rendering of the exact positioning of the railings, pipes, and passageways and their features. The second step was the modelization of the worker, based on the aforesaid model, taking into account the characteristics of the operator assigned to the task (in the example herein discussed, a 1.70 m tall thin man) and the simulation of his interaction with the working environment. In the following figures are shown some frames of the final animation for the considered operation, a detailed description of the task being previously collected in order to reconstruct the real sequence of actions performed by the worker during his job. The aim was to verify the safety conditions of the task, both in the phase of approaching the valve and with reference to the position and measures of the railing. The possibility of choosing the point of view by rotating of 360° all around the 3D image resulted
Table 1 Fatal injuries (numbers and rates) from US official data – 2007. Industry sector
Number
Ratea
Numbers and rates of fatal occupational injuries by industry sector – USA (2007) Construction 1178 0.10 Transportation and warehousing 836 0.16 Agriculture, forestry, fishing and hunting 573 0.27 Government 532 0.02 Professional and business services 465 0.03 Manufacturing 392 0.02 Retail trade 336 0.02 Leisure and hospitality 251 0.02 Wholesale trade 197 0.05 Mining 181 0.25 Other services (exc. public admin.) 170 0.03 Educational and health service 149 0.01 Financial activities 116 0.01 Information 77 0.02 Utilities 33 0.04 a The rates represent the number of fatal occupational injuries scaled to 1000 employed workers.
Table 2 Fatal injuries (numbers and rates) from Italian official data – mean value 2003–2005. Industry sector
Number
Ratea
Numbers and rates of fatal occupational injuries by industry sector – Italy (mean value 2003–2005) Construction 319 0.20 Manufacturing 303 0.05 Transportation 176 0.11 Estate commercial and linked activities 71.3 0.03 Wholesale trade 45.7 0.04 Leisure and hospitality 39 0.03 Retail trade 37 0.03 Car trade and repairing 32.3 0.06 Other public services 25.7 0.03 Educational and health service 19.7 0.01 Agriculture and fishing 14.33 0.06 Public administration 17.7 0.01 Mining 10.7 0.18 Financial activities 14.0 0.01 Electric, gas and sanitary services 8 0.03 Indefinite 55.7 – a The rates represent the number of fatal occupational injuries per 1000 employed workers.
514
M. Patrucco et al. / Safety Science 48 (2010) 508–516
Fig. 6. Some frames from the CIGJS animation.
Fig. 7. Some examples of the possibilities given by the interactive environment.
to be of great help for the analysts in the identification of criticalities and residual risk. The proposed example clearly shows the safety conditions of the worker in the real situation, and it highlights how an operator with notably different anthropometric characteristics may be exposed to different hazards: e.g. if too tall, the railing height may be inadequate; if short of stature, he/she may experience overextension.
5. Results and discussion As shown in the case study (4), by use of the JSA + CIGJS method, a specific operation was examined step by step (Fig. 6) and analyzed in detail (Fig. 7). First, the JSA technique permitted the identification of the basic tasks involved in the specific operation, then, CIGJS provided the visualization of the scenario and the intuitive understanding of the designed layout. Moreover, some organizational and ergonomic concerns resulted from said analysis, allowing the creation of tailored procedures taking into account the true boundaries of these conditions.
The pneumatic transportation system proved to be reachable if the operator corresponds to the characteristics of the model, but with arms fully extended: this leads to a situation that needs structural change, since on the one hand a different worker could be unable to do the task, and also the model experiences a nonergonomic condition. Also, the valve should be rotated in order to allow an easier control and minor efforts in its manipulation. Even when the JSA + CIGJS approach is applied to correctly organize a new task, in terms of workers S&H and job efficiency, this appears to be a unique option for an effective preliminary Risk Analysis, upon which basing the area layout design and the task organization program, the appropriate machinery and tool selection, and the definition of detailed operating safety procedures. A virtually infinite number of different options in terms of working conditions and modus operandi may be accurately investigated and compared in detail, in order to evaluate the most suitable solutions for eliminating or, if not possible, minimizing the risks to the workers. As far as workers’ education and training are concerned, it is well known that some particular aspects have to be considered,
M. Patrucco et al. / Safety Science 48 (2010) 508–516
because of different learning mechanism in elderly vs. younger people and the aim itself of adult education processes. In fact, the education and training of adults must give rise to theoretical knowledge, but moreover proper attitudes and subsequently practical skills that shall be applied in real situations (Knowles, 1984). First, it is fundamental that the learner totally understands the problems, in order to implement the right actions and solutions (Barrows and Tamblyn, 1980). In order to fulfill these needs, a series of teaching methodologies have been specially developed for fields where pure knowledge, practical skills, and problem solving capabilities are fundamental (e.g. medical education). In particular, these methodologies can involve case studies, small group discussions, Problem Based Learning, and so on. These methods have been proven to have their effect by the activation of previous knowledge processes and the capability to adapt the information to the specific context. Therefore, these methodologies facilitate the activation of prior knowledge and elaboration of newly acquired information, thereby enhancing the retention of knowledge (Norman and Schmidt, 1992). This being the situation, the CIGJS method can be a helpful tool also in workers’ education and training, able to resolve some difficulties that affect the construction sector. In fact, from a research study on training effectiveness in the construction field, it was also inferred that training is more effective when delivered by someone who knows the subject, has experience in the job, and is familiar with the job-specific risks (Tackett et al., 2006). According to the interviewed workers, formal training programs came out to fail in addressing the ‘‘real-life” hazards; they also emphasized that practical, hands-on knowledge and a focus on job-specific skill sets are critical to the effectiveness of the training. CIGJS stresses the importance of participation and consultation of workers, who are actively involved in the simulation process, especially when the specific task has to be analyzed and ‘‘captured” by the cameras. The final result is a realistic environment, obtained from CAD files and photographs, where real workers contributed in simulating the task, thus overcoming the traditional training problems. Finally, CIGJS, giving the opportunity to take into account the specific anthropometric characteristics of each worker, can lead to an appropriate selection of the members of the crew to which particular tasks should be committed (for instance, in case of emergencies, or where critical boundary conditions are present, as sometimes occurs in certain industrial sectors – e.g. mining).
6. Conclusion Thanks to the introduction of the computer image generation for job simulation (CIGJS) approach into the usual Job Safety Analysis (JSA) technique, a substantial improvement in the analysis capabilities both in routine conditions and in difficult situations was successfully achieved. The new JSA + CIGJS approach gives the possibility to achieve easier, faster, and much more intuitive considerations on the hazards possibly present in each working operation and on their effective control. It allows realistic simulation of the real workplaces and of the tasks actually performed by the workers, helping the Risk Analysts in their job and overcoming the JSA traditional limits. In fact, by use of JSA technique in its traditional approach, only one operation at a time may generally be considered, with no possibility of interference evaluation; also, only actual operating situations may be dealt with, because of the difficulties in the definition of scenarios not already in existence. JSA + CIGJS discloses new and interesting possibilities in the Risk Analysis and Management of new operating layouts at the very first design stage (both in normal and emergency situations), contributing effectively to a Prevention through Design (PtD) approach.
515
Thanks to a series of successful in-field tests, which confirmed flexibility, detail, and good usability, the Authors are convinced that the discussed evolution of a well-known and widely used Risk Analysis and Management technique like the Job Safety Analysis will be appreciated by the Risk Analysts and Safety Trainers, and it will substantially contribute to improve both the work efficiency and the occupational Safety and Health conditions. As a matter of fact, the method, apart from showing the actual S&H conditions, gives information on the effectiveness of the adopted countermeasures: the possibility to forecast the effect of a design improvement and to ‘‘visualize” the results of the proposed solutions represents a further improvement in the aforesaid PtD approach and a useful and intuitive tool for Risk Analysts and designers. At present, a Job Safety Analysis performed with the proposed approach has a notable cost, but the encouraging results and the decreasing trend in programming costs suggest, for the future, a wide range of useful applications suitable for the ‘‘non-major-accident hazards” industrial sectors. The JSA + CIGJS method shows interesting aspects also in the European Directives context: as regards ‘‘Council Directive 89/391/EEC of 12 June 1989 on the introduction of measures to encourage improvements in the safety and health of workers at work”, wherein it is clearly stated that the employer shall take the measures necessary for safety and health protection of the workers by ‘‘adapting the work to the individual, especially as regards the design of work places, the choice of work equipment and the choice of working and production methods, with a view, in particular, to alleviating monotonous work and work at a predetermined work-rate and to reducing their effect on health”, also ‘‘developing a coherent overall prevention policy which covers technology, organization of work, working conditions, social relationships, and the influence of factors related to the working environment”; in the eyes of the Machinery Directive that will become effective on December 29th, 2009 (Directive 2006/42/EC of the European Parliament and of the Council of 17 may 2006 on Machinery, and amending Directive 95/16/EC), where it is highlighted that the design phase should take into account not only setup, installation, intended use, maintenance, and cleaning, but also ‘‘any reasonably foreseeable misuse”. A possible future development may be found in the field of education and training of workers on correct and safe working procedures, up to a possible use as an effective simulation-training device. In fact, the choice of a 3D interface with near real-world representation allows learning-by-doing and case-based reasoning approaches, stressing the importance of participation and consultation of workers. The final result of a realistic environment where real workers contribute in simulating the task, helps to overcome the traditional training problems due to theoretical approach and lack of specificity. References Alfaro Degan, G., Pinzari, M., 2001. The functional analysis space technique (FAST) in risk analysis. In: Zio, E., Demichela, M., Piccinini, N. (Eds.) Proceedings of the European Conference ESREL 2001: Towards a Safer World, Torino, Italy, pp. 847–954, ISBN 88-8202-099-5. Arcangeli, G., Del Bimbo, A., Vicario, E., 1999. Use of virtual reality for instruction and training of young workers (European Project SAFE). Preliminary data, In: Proceedings of the ‘International Conference on Computer-aided Ergonomics and Safety’, Barcelona, Spain, pp. 1232–1239. Assfalg, J., Del Bimbo, A., Vicario, E., 2002. Using 3D and ancillary media to train construction workers, IEEE Multimedia. Barrows, H.S., Tamblyn, R.M., 1980. Problem-based Learning: An Approach ti Medical Education. Springer Publishing Company, New York. Behm, M., 2008. Rapporteur’s report construction sector. Journal of Safety Research 39 (2), 175–178.
516
M. Patrucco et al. / Safety Science 48 (2010) 508–516
Camisassi, A., Cigna, C., Patrucco, M., 2004. Sicurezza nei cantieri: analisi di rischio e condizioni di impiego in sicurezza di macchine operatrici e mezzi di sollevamento di materiali, GEAM-Geoingegneria ambientale e mineraria XLI, vol. 3, pp. 19–32. Camisassi, A., Cigna, C., Nava, S., Patrucco, M., Savoca, D., 2006. Load and hauling machinery: an evaluation of the hazard involved as a basis for an effective risk evaluation. In: Cardu, M., Ciccu, R., Lovera, E., Michelotti, E. (Eds.) Proceedings of Mine Planning and Equipment Selection (MPES 2006), Torino, Italy, pp. 395– 400, ISBN 88 901342 4 0. Chao, E.L., Henshaw, J.L., 2002. Occupational safety and health administration. Job Hazard Analysis.. Faina, L., Patrucco, M., Savoca, D., 1996. La valutazione dei rischi ed il documento di sicurezza e salute nelle attivita’ estrattive a cielo aperto. In: S.H.C.M.O.E.I. (Ed.) Guidelines for Risk Assessment in Italian Mines. Doc. No. 5619/96 EN – S.H.C.M.O.E.I., Luxembourg, pp. 46–71. Gambatese, J., Hinze, J., 1999. Addressing construction worker safety in the design phase designing for construction worker safety. Automation in Construction 8, 643–649. Gettman, M.T., Le, C.Q., Rangel, L.J., Slezak, J.M., Bergstralh, E.J., Krambeck, A.E., 2008. Analysis of a computer based simulator as an educational tool for cystoscopy: subjective and objective results. The Journal of Urology 179 (1), 267–271. Howard, J., 2008. Prevention through design – introduction. Journal of Safety Research 39 (2), 113. Imai, S., Tomii, T., Arisawa, H., 2002. Motion Simulation of the Human Workers for the Integrated Computer-aided Manufacturing Process Simulation Based on Info-Ergonomics Concept, ER 2001 Workshops, pp. 105–114. Ioannidou, I.A., Paraskevopoulos, S., Tzionas, P., 2006. An interactive computer graphics interface for the introduction of fuzzy inference in environmental education. Interacting with Computers 18 (4), 683–708. Istituto Nazionale per l’Assicurazione contro gli Infortuni sul Lavoro (INAIL), 2008. Official Statistics.
Lainema, T., Nurmi, S., 2006. Applying an authentic, dynamic learning environment in real world business. Computers & Education 47 (1), 94–115. Manuele, F.A., 1997. On the practice of safety, ISBN 9780471272755. Mujber, T.S., Szecsi, T., Hashmi, M.S.J., 2004. Virtual reality applications in manufacturing process simulation. Journal of Materials Processing Technology 155–156, 1834–1838. National Occupational Health and Safety Commission. Australian Government, 2004. The role of design issues in work related injuries in Australia 1997–2002. ISBN 1 920763 32 5. Norman, G.R., Schmidt, H.G., 1992. The psychological basis of PBL. A review of the evidence. Academic Medicine 67, 557–565. Passman, M.A., Fleser, P.S., Dattilo, J.B., Guzman, R.J., Naslund, T.C., 2007. Should simulator-based endovascular training be integrated into general surgery residency programs? The American Journal of Surgery 194 (2), 212–219. Pellegrino, V., 2008. Analisi dei rischi: schede, pensieri, parole, In: Proceedings of ANIM ‘Sicurezza e tutela dell’ambiente nell’impiego di macchine operatrici e impianti mobili’ SAMOTER 08, Verona, Italy, pp. 71–80. Pfahl, D., Laitenberger, O., Ruhe, G., Dorsch, J., Krivobokova, T., 2004. Evaluating the learning effectiveness of using simulations in software project management education: results from a twice replicated experiment. Information and Software Technology 46 (2), 127–147. Regione Lombardia, 2002. Criteri per la valutazione dei rischi e la redazione del Documento di Sicurezza e Salute (DSS e DSS Coordinato) ai sensi dell’art. 6, comma 1, del decreto legislativo no. 624/1996 nel comparto estrattivo. Official Bulletin BURL 2002, no. 8, Annex 2. Salvi, O., Merad, M., Rodrigues, N., 2005. Toward an integrated approach of the industrial risk management process in France. Journal of Loss Prevention in the Process Industry 18, 414–422. Tackett, J., Goodrum, P.M., Maloney, W.F., 2006. Safety and health training in construction in Kentucky. The Center to Protect Workers’ Rights (CPWR) US Bureau of Labor Statistics, US Department of Labor, 2008. Official Statistics.. Zheng, X., Liu, M., 2009. An overview of accident forecasting methodologies. Journal of Loss Prevention in the Process Industry 22, 484–491. Zio, E., Podofillini, L., Zille, V., 2006. A combination of Monte Carlo simulation and cellular automata for computing the availability of complex network systems. Reliability Engineering and System Safety 91, 181–190.
Contents lists available at ScienceDirect
Safety Science journal homepage: www.elsevier.com/locate/ssci
Computer image generation for job simulation: An effective approach to occupational Risk Analysis Mario Patrucco a, Daniele Bersano a, Caterina Cigna a,*, Federico Fissore b a b
DITAG Politecnico di Torino, Cso Duca Abruzzi 24, 10124 Torino, Italy Visualink, Pzza Castello 2, 10040 Osasio (TO), Italy
a r t i c l e
i n f o
Article history: Received 24 February 2009 Received in revised form 23 December 2009 Accepted 30 December 2009
Keywords: Job Safety Analysis Risk Analysis Prevention Computer simulation
a b s t r a c t The paper deals with the general approach and features of the computer image generation for job simulation (CIGJS) method, as specially developed to support the Job Safety Analysis (JSA) technique. Starting from some general considerations on the occupational safety and health statistical data collection in Italy, when compared to US methodology, the paper provides an overview of the CIGJS method, developed to improve the effectiveness and usability of the traditional JSA. A case study is discussed in order to highlight how CIGJS makes the use of the JSA technique possible also at the design stage (this being fundamental according to a Prevention through Design approach), and allows to control the effectiveness of the adopted countermeasures. The application of the method complies with the basic European Directives requirements both on workers’ safety and health and on machinery analysis. Furthermore, CIGJS may substantially aid workers’ education and training, to the point of being a possible simulation-training device. Ó 2010 Elsevier Ltd. All rights reserved.
1. Introduction The Job Safety Analysis (JSA) technique – based on the common Risk Analysis approach consisting in a thorough analysis of the various sub-tasks in which a macro working task may be logically subdivided – is a widely used and powerful tool to effectively identify the possible hazards associated with each working sub-operation, together with the respective time duration, so that, step by step, the hazards involved, the associated risk, and the practically applicable technical and procedural countermeasures may be directly identified, evaluated both in terms of effectiveness and cost, and finally developed. The great variety of data drawn from different industry sectors has always been a bar to a widespread application of the JSA technique; moreover, for a proactive Risk Analysis of new tasks or work conditions, JSA alone may not be the most suitable solution. Providing a realistic simulation of the actual work situation, computer image generation for job simulation (CIGJS) can rather successfully contribute to the analysis, improving the effectiveness and usability of the conventional JSA in routine work situations, and making the use of JSA possible also at the design stage, since a virtually infinite number of different options in terms of area * Corresponding author. Address: DITAG Politecnico – Corso Duca degli Abruzzi, 24, 10129 Torino, Italy. Tel.: +39 011 090 7733; fax: +39 011 090 7699. E-mail addresses: [email protected], [email protected] (C. Cigna). 0925-7535/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.ssci.2009.12.025
layout, working conditions and procedures may be compared in detail. The critical rates of occupational injuries and fatalities, typical of some industry sectors, need to be faced with suitable Risk Analysis techniques, therefore the use of JSA + CIGJS method may be an important improvement in order to minimize the risk conditions at workplaces. Finally, further development of the CIGJS method are expected in the field of workers’ education and training, following the successful application of computer-based simulations to several educational scenarios in the fields of medicine, engineering, computer science, environmental education, and business (Mujber et al., 2004; Pfahl et al., 2004; Ioannidou et al., 2006; Lainema and Nurmi, 2006; Passman et al., 2007; Gettman et al., 2008). 1.1. Industrial safety and health situation at present Official data from INAIL (Italian Workers’ Compensation Authority) show a situation of three fatal accidents per day1 (INAIL, 2008); it is clear that the only way to reduce such an unacceptable rate is to carry out an effective Risk Analysis and undertake proactive preventive actions based thereon. In fact, it should be known that ‘‘one of the best ways to prevent and control occupational injuries,
1
Official INAIL data of fatal injuries: 1207 fatalities in 2007.
M. Patrucco et al. / Safety Science 48 (2010) 508–516
509
Fig. 1. Data drawn from direct in-depth analysis of fatal accidents causes.
illnesses and fatalities is to ‘design out’ or minimize hazards and risks early in the design process” (Howard, 2008). The Safety and Health (S&H) of workers at the workplace is a concerned problem in all countries, not only in Italy, as exemplified by the data listed in Tables 1 and 2. Besides territorial differences that obviously affect the data comparison, the use of a different methodological approach has resulted in a obstacle to the statistical analysis of occupational S&H data in USA and Italy. In fact, Italian rates of fatal injuries consider a 3-year period and refer to a base of 1000 workers employed in the industry sector, while the US rates are annual and refer to a base of 100,000 workers. Referring to the following tables, the Authors had to scale US rates in order to obtain comparable values, losing details of the data (on the other hand, scaling of Italian rates would have led to greater error). From both the reported statistics it is clear that the construction sector represents the most critical industry sector in terms of number of fatalities, as already discussed by many authors (Gambatese and Hinze, 1999; Behm, 2008). In the USA – even if the highest rate pertains to agriculture, forestry, fishing, and hunting, followed by mining – as far as the number of fatalities is concerned, construction exceeds more than three times the average value and lies above the following sector (transportation and warehousing) by 30%. The Italian situation is even clearer, with the construction sector fatalities representing the first cause of death among workers, both taking into account the rate (more than three times higher than the average) and the number (four times higher than the average). Another sector that appears to be critical is mining, which – despite a number of fatalities lower than the average – shows the second rate value on both charts. The differences between the two countries are not negligible (e.g. in terms of dimension, mined materials, techniques, and technologies); however, this sector is particularly noteworthy and general considerations can be made. Based on the Authors’ research group experience (Pellegrino, 2008), basically focused on construction and mining activities, the main causes of industrial work-related accidents in Italy have been studied, in order to identify the critical aspects at the design stage and to establish a suitable hierarchical list of preventive interventions (the main results being summarized in Fig. 1).
This being the situation, the main steps to face the problem in a correct way should be: An in-depth analysis of past events (e.g. a collection of data on standard violations, real machinery conditions, use procedures, etc.); a proactive approach to foresee the critical situations in detail and immediately correct any safety flaws. 1.2. Criticality ranking It is demonstrable that a detailed analysis of occurred events is essential to collect exhaustive information about the causes lying at the very core of the event, and hence to identify properly the corrective actions to adopt. A significant example of such an approach may be drawn from OSHA data collection, wherein specific standard violation is provided.2 Unfortunately, in Italy no official records are available on the violations of occupational S&H standards and laws. Therefore, no general considerations useful for an effective preventive action may be drawn on this basis for now. Some attempts were developed in the past by the Authors’ research group for a number of case studies related to major accidents, e.g. loading and haulage of machinery in construction sites (Camisassi et al., 2004), the target of the research work being the identification of the most critical machinery type. The approach led to a numerical evaluation of the criticality factor KR, defined as
KR ¼
no: of recorded fatalities=no: of machines hours of use shift=shift duration
whose meaning may be summarized as follows: the smaller the number of used machines of the considered type and the smaller the percentage of work shift during which the machines are used, 2 The literal meaning of ‘‘safety” being ‘‘lack of risk”, a true zero-risk condition is not always achievable unless by suppressing the risk-causing activity: this leads to the culture of acceptable risk, where the limit value may be reached basically by meeting a set of technical standards and S&H requirements.More stringent requirements, may or may not be technologically feasible at a given time: in the interest of workers’ S&H, the risks vs. benefits of the possible alternatives must be carefully considered.
510
M. Patrucco et al. / Safety Science 48 (2010) 508–516
Definition: KR = [n° recorded fatalities / n° machines] / [hours of use shift / shift duration] Experimental data n° recorded fatalities / n° machines
hours of use shift / shift duration
2.5
0.8 0.7
2
0.6 1.5
0.5 0.4
1
0.3 0.2
0.5
0.1 0 excavator
off highway truck
0
rubber tyred loader
excavator
off highway truck
rubber tyred loader
Final result KR values for some widely used machines 6 5 4 3 2 1 0 excavator
off highway truck
rubber tyred loader
Fig. 2. Criticality factor KR for loading and haulage of machinery in construction sites.
the higher the criticality factor KR (see Fig. 2) (Camisassi et al., 2006). Obviously, the work analysis based on a set of non-homogeneous or incomplete data can only lead to partial results, as may be drawn from a series of similar experiences (e.g. NOHSC, 2004). Where new working situations are introduced, JSA + CIGJS makes the analysis of the safety criticalities at the first design stage possible, with the aim of carrying into evidence the S&H problems and the necessary control measures, to support properly the Hazard Identification and Risk Analysis and Management frames, contributing effectively to a Prevention through Design (PtD – NIOSH) approach. 2. The basic approach of the proposed Risk Analysis technique The main results achieved by the Authors with the target of providing well-tested guidelines for an effective approach to the Risk Analysis and Management were presented during the S.H.C.M.O.E.I – Safety and Health Commission for the Mining and Other Extractive Industries – Workshop on Risk Assessment, in 1996 (Faina et al., 1996) and were published in the Official Gazette of Lombardia Region (Regione Lombardia, 2002). It must be underlined that, even if originally developed for mining and earthmoving activities, the approach was successfully adopted in a number of different industrial typologies. The main features of the quoted approach may be described as in the following considerations: a correct Risk Analysis may only be performed for situations accomplishing the requirements of standards and laws; preliminary and constant Risk Analysis and control are needed (e.g. site characteristics, special countermeasures, basic safety structures, fitting and organization, emergency and rescue teams), in a continuous improvement approach; the assessment of the contact factor (evaluated as the percentage of time/shift during which there is exposure to a certain risk
factor) and the identification and management of interferences are fundamental tasks for the correct evaluation of the actual risk conditions; the use of widely recognized, well-tested and suitable Risk Analysis techniques is of paramount importance, both for safety analysis and control of each working activity (e.g. through JSA) and for failure analysis and control of hazardous plants or operations (e.g. HAZOP and FTA). The Job Safety Analysis (JSA) technique – based on the common Risk Analysis approach consisting in an in-depth analysis of the various sub-tasks in which a macro working task may be logically subdivided – is a widely used and powerful tool to identify effectively the possible hazards, together with the time duration related to each working sub-operation, as stated also by OSHA (‘‘One of the best ways to determine and establish proper work procedures is to conduct a Job Hazard Analysis”) (Chao and Henshaw, 2002). The JSA technique focuses on the relationship among the worker, the task, the tools, and the work environment, so that, step by step, the hazards involved, the associated risk, and the practically applicable technical and procedural countermeasures may be directly identified, evaluated in terms of effectiveness and cost, and finally put in effect – as shown in Fig. 3 – to eliminate or reduce the risk to an acceptable level. Further, Risk Analysis is the basis on which setting up a correct, suitable, and effective Risk Assessment, this being – according to the European Community definition – ‘‘a systematic examination of all aspects of the work undertaken to consider what could cause injury or harm, whether the hazards could be eliminated, and if not what preventive or protective measures are, or should be, in place to control the risks”. Risk Analysis techniques are the tools to identify hazards and workers at potential risk from those hazards, finally providing a quantification of the risk involved. With these data, the management will then apply the hierarchy of control measures (elimination, substitution, reduction at the source, collective protection, PPE).
M. Patrucco et al. / Safety Science 48 (2010) 508–516
511
Fig. 3. JSA procedure for a proactive prevention approach.
Unfortunately, in its traditional approach, the JSA technique has some not negligible intrinsic limits, which reduce the possibility of use in some particular situations: the analysis of possible interferences (e.g. between machines and people in narrow areas) is relatively complex and time consuming; therefore, as a matter of fact, only one operation at a time shall be considered; it should be noted that only the actual operating situations may be considered, since when a new task requires to be organized correctly in terms of job efficiency and workers S&H – this being e.g. the case of special maintenance or emergency operations – the results are remarkably less reliable, due to the difficulties in defining the scenarios not already in existence. A substantial improvement in the analysis capabilities both in routine conditions and in the aforesaid difficult situations was successfully achieved thanks to the introduction, in the traditional JSA technique, of the computer image generation for job simulation (CIGJS) approach, which is based on virtual images, animation, and 3D interactive environment, as specially developed for JSA purposes. Therefore, CIGJS should be considered as a helpful tool to support the application of the JSA technique, in the eyes of a wider Risk Assessment. In fact, CIGJS permits an intuitive and complete Hazard Identification and an interference definition, either between worker/machinery or worker/worker. However, a preliminary subdivision of the working task by means of JSA is essential. The choice of the JSA technique among other Risk Analysis techniques is due to the possibility of focusing on the sub-tasks, the related hazards, and the adopted (or foreseen) risk control measures. At present, there exist many validated and up-to-date methods (often based on numerical simulation, e.g. Monte Carlo methods, Fuzzy Logic) suitable for the Risk Analysis. Generally, they are developed for major accident scenarios, and mainly devoted to the analysis of very complex systems and situations (Konstandinidou et al., 2006; Zio et al., 2006). These techniques, formerly developed for chemical or nuclear plants, show some common characteristics: they need a very detailed description of plants, systems, and machinery; they refer to system faults or human errors; and finally they are aimed at retrieving information about collective protection of workers or communities (Salvi et al., 2005). Large, detailed, and representative statistical data are fundamental as input and dramatically affect the results, the final aim of the methods being the forecasting of accident scenarios (Zheng and Liu, 2009). Unfortunately, in a series of real industrial situations (as construction sites or extractive activities), some of the described requirements cannot be applied; for instance, activities and layout features can considerably vary in different quarry plants and the statistical basis becomes, if present, inadequate to provide useful data.
Since the aforesaid methodologies appear to be too complex or over-dimensioned for ‘‘normal” industrial sectors, the JSA + CIGJS approach is proposed as a suitable option. 3. Computer image generation for job simulation (CIGJS) supporting Job Safety Analysis 3.1. The software The computer image generation for job simulation has been set up in cooperation with Visualink, a multimedia, and web design agency. After a deep study of the project and a comparison of the different state-of-the-art products, the agency decided to adopt Lightwave 3DÒ. This software is widely used to create images, animations, and simulations, allowing the user to work at different levels of complexity from basic situations – which obviously need a relatively short time for development – to complex simulations, as for instance epithelial tissues, physical and fluid dynamics laws, etc. With a wide community of users that contributes to the development of specific additional features, such as architectural, geological, mechanical, and medical items, Lightwave 3DÒ is globally considered as one of the most versatile graphic software products on the market. 3.2. Software characteristics When a scenario has to be simulated, it is possible to create a 3D environment using photographs or planimetries from CAD files, an orthogonal projection finally producing solid objects. In order to reach a photo-realistic effect once the object has been created, the surfaces are imported from photographs and ‘‘pasted” on the object. The last stage of creation of the environment is the positioning of the objects in a virtual place where lights, cameras, and animations may be set up for a future use. Now, the 3D environment is ready for the rendering of images and animations to create 3D realistic movies, or for the exportation, allowing the final user to operate in a real-time interaction. Once the environment is completed, various elements may be added, such as doors, joints, mechanical arms, or natural features (water, gases, etc.). This is particularly important for the target of the research work herein described, because it permits to take into account the features and the behavior of work environment, machinery, etc., in a realistic manner. 3.3. Potentiality Every object created may be modified afterward, in order to improve the photo-realistic output or the proportions in relation with the environment. If the object cannot be modified, it may be replaced by a new one ad hoc programmed.
512
M. Patrucco et al. / Safety Science 48 (2010) 508–516
In the example herein proposed, the man responds to the anthropometric parameters according to the international standards (UNI EN ISO 7250:2000 – Basic human body measurements for technological design, UNI EN 547-2 1998 Human body measurements – principles for determining the dimensions required for access openings and UNI EN 547-3 1998 Human body measurements – anthropometric data). It is also possible to modify the worker’s anthropometric parameters while maintaining the same sequence of actions aimed at achieving the final target. The software allows the animation of the character to be bound as in the real world, building a skeleton inside the body and limiting the articulations movements permitted, while skin and muscular behavior are also simulated. This is obtained through both the Inverse Kinematics command, based on mechanics, and the Motion Capture mode, a stereophotogrammetric system based on ‘‘capturing” the real movements of a person wearing a black suit with lights on the joints in a cameras-surrounded environment. The recorded data are mapped to create a 3D model performing the same actions as the observed subject (see Figs. 4 and 5). Every object can then be bound by itself or by other objects in the environment and, after implementing physical laws, collisions, weights, forces, frictions and all kinds of interactions between people and/or machineries may be simulated. Because of its versatility and efficiency, the software is used in the film-making industry, wherein a lot of special effects are asked to interact with the characters. These features may be useful to simulate the actions of a real worker in a real scenario, for instance, with the aim to investigate the possibility of a contact with harmful parts of machinery or equipment, or to avoid overextension, etc.
3.4. Limits and criticalities Virtually, the software has no defined limits, and the potential is basically immeasurable. Obviously, the basic version presents a number of limits, but through plug-ins and customizable scripts, these can be overcome. The software is created so that you can build a virtual reality which is as ‘‘authentic” as possible, while
Fig. 4. Graphical model for human body, developed to be strictly linked to anthropometric parameters.
reproducing rules considering measurements of length (in meters or feet), weight (in kilograms or pounds), angles (in radians or degrees), temperatures (in Celsius or Fahrenheit), etc. The real limit lies in the possibility of modifying the project only within the software, before generating the final support (a static image, a movie, a 3D interactive environment, etc.), that would otherwise need the generation of new media. 3.5. Opportunities It is important to remember that the European regulation states that the Employer shall provide all information, instruction, training, and supervision that may be necessary to ensure the health, safety, and welfare of the workers and other persons while at work (Council Directive 89/391/EEC). Also, great consideration is given to the consultation and participation of workers, cornerstone in determining safety and health concerns and the subsequent suitable safety measures. In the past, some experimental work on the use of virtual environments for construction workers education and training were conceived (Arcangeli et al., 1999; Assfalg et al., 2002) and proved to be effective, demonstrating that ‘‘using the system would give the user a positive impression about the suitability of 3D graphics as a training system”. Other positive experiences can be found in the field of InfoErgonomics (Imai et al., 2002), wherein aspects like comfort of the workers and optimal human/machine co-existence are taken into account. The authors of this research stated that ‘‘modeling human beings and creating virtual employees via computer graphics still has a very limited use, because of the human body’s high complexity and the limits imposed by the computer techniques”. Recent developments in computer graphics software allowed the Authors to develop the proposed method, using more complex and realistic models for the description of human body and workers’ skills. Therefore, with the described software it was possible to obtain a realistic simulation of a real workplace and of the tasks actually performed by the workers, so that the new JSA + CIGJS approach permits easier, faster, and much more intuitive analysis of the hazards potentially present in each sub-task, and their effective control. The workers themselves play an important role in defining the simulation parameters, thus actively contributing to the health and safety of the specific workplace they are already working in or they will operate in. If developed for educational purposes, the method can provide a simulation-training device, with the advantage of a 3D interface with near real-world representation, for applying learning-bydoing and case-based reasoning approaches. In case of routine operations, each sub-task may now be reproduced on a computer display – again and again where necessary – and analyzed to identify the possible safety criticalities, thus reducing the number of in-field operations.3 The attainable accuracy is relatively high, since site and machinery data may be obtained from CAD files reproducing the area, while the worker movements and behavior may be evaluated from digital cameras or video recordings; the possible control alternatives themselves may be easily analyzed and discussed to identify the safest and most effective solution. Moreover, the possibility of ‘‘rewinding” the CIGJS images may be helpful to analyze multiple operations, the involved interference problems being easily highlighted, thus simplifying the
3 Nevertheless, it must be strongly underlined that at least one direct task observation by the Risk Analysts is in any case necessary, together with the discussion of the criticalities identified in cooperation with the workers in order to get essential info on modus operandi, on hidden problems and on the feasible control measures. As a consequence, video recordings cannot replace exhaustively direct observation, but should be considered only as a helpful tool for the CIGJS.
513
M. Patrucco et al. / Safety Science 48 (2010) 508–516
Fig. 5. General view of the plant as resulting from the simulation model.
approach to different analysis techniques such as Functional Space Analysis (Alfaro Degan and Pinzari, 2001). If used with the aim of studying the safety conditions for new plants or in case of improvement/renewal of the existing ones, JSA + CIGJS could effectively represent a powerful means to draw attention to critical situations, allowing the identification of the suitable solutions in accordance with the correct hierarchy of controls (Manuele, 1997), directly at the design stage (as stated in the basics of NIOSH PtD program).
4. A case study As described in Tables 1 and 2, construction and mining sectors proved to be critical in terms of fatalities: official data show that these industrial sectors are at the top of the criticality ranking, in terms of number and accident rates. Moreover, falls represent a statistically significant cause of fatality in the aforesaid activities (US Bureau of Labor Statistics, 2008, and ISPESL et al., 2006), even if a number of regulatory requirements, technical solutions, and procedures exist to protect the workers. This being the scenario, the Authors decided to apply the JSA + CIGJS to an existing pneumatic transportation system located in a crushing plant for extractive activities, where a simple operation, consisting in the regulation of a valve on top of a 15 m silo, was found to be critical. First of all, the virtual environment was set up based on CAD files and pictures taken during a preliminary direct inspection; particular care was dedicated to the rendering of the exact positioning of the railings, pipes, and passageways and their features. The second step was the modelization of the worker, based on the aforesaid model, taking into account the characteristics of the operator assigned to the task (in the example herein discussed, a 1.70 m tall thin man) and the simulation of his interaction with the working environment. In the following figures are shown some frames of the final animation for the considered operation, a detailed description of the task being previously collected in order to reconstruct the real sequence of actions performed by the worker during his job. The aim was to verify the safety conditions of the task, both in the phase of approaching the valve and with reference to the position and measures of the railing. The possibility of choosing the point of view by rotating of 360° all around the 3D image resulted
Table 1 Fatal injuries (numbers and rates) from US official data – 2007. Industry sector
Number
Ratea
Numbers and rates of fatal occupational injuries by industry sector – USA (2007) Construction 1178 0.10 Transportation and warehousing 836 0.16 Agriculture, forestry, fishing and hunting 573 0.27 Government 532 0.02 Professional and business services 465 0.03 Manufacturing 392 0.02 Retail trade 336 0.02 Leisure and hospitality 251 0.02 Wholesale trade 197 0.05 Mining 181 0.25 Other services (exc. public admin.) 170 0.03 Educational and health service 149 0.01 Financial activities 116 0.01 Information 77 0.02 Utilities 33 0.04 a The rates represent the number of fatal occupational injuries scaled to 1000 employed workers.
Table 2 Fatal injuries (numbers and rates) from Italian official data – mean value 2003–2005. Industry sector
Number
Ratea
Numbers and rates of fatal occupational injuries by industry sector – Italy (mean value 2003–2005) Construction 319 0.20 Manufacturing 303 0.05 Transportation 176 0.11 Estate commercial and linked activities 71.3 0.03 Wholesale trade 45.7 0.04 Leisure and hospitality 39 0.03 Retail trade 37 0.03 Car trade and repairing 32.3 0.06 Other public services 25.7 0.03 Educational and health service 19.7 0.01 Agriculture and fishing 14.33 0.06 Public administration 17.7 0.01 Mining 10.7 0.18 Financial activities 14.0 0.01 Electric, gas and sanitary services 8 0.03 Indefinite 55.7 – a The rates represent the number of fatal occupational injuries per 1000 employed workers.
514
M. Patrucco et al. / Safety Science 48 (2010) 508–516
Fig. 6. Some frames from the CIGJS animation.
Fig. 7. Some examples of the possibilities given by the interactive environment.
to be of great help for the analysts in the identification of criticalities and residual risk. The proposed example clearly shows the safety conditions of the worker in the real situation, and it highlights how an operator with notably different anthropometric characteristics may be exposed to different hazards: e.g. if too tall, the railing height may be inadequate; if short of stature, he/she may experience overextension.
5. Results and discussion As shown in the case study (4), by use of the JSA + CIGJS method, a specific operation was examined step by step (Fig. 6) and analyzed in detail (Fig. 7). First, the JSA technique permitted the identification of the basic tasks involved in the specific operation, then, CIGJS provided the visualization of the scenario and the intuitive understanding of the designed layout. Moreover, some organizational and ergonomic concerns resulted from said analysis, allowing the creation of tailored procedures taking into account the true boundaries of these conditions.
The pneumatic transportation system proved to be reachable if the operator corresponds to the characteristics of the model, but with arms fully extended: this leads to a situation that needs structural change, since on the one hand a different worker could be unable to do the task, and also the model experiences a nonergonomic condition. Also, the valve should be rotated in order to allow an easier control and minor efforts in its manipulation. Even when the JSA + CIGJS approach is applied to correctly organize a new task, in terms of workers S&H and job efficiency, this appears to be a unique option for an effective preliminary Risk Analysis, upon which basing the area layout design and the task organization program, the appropriate machinery and tool selection, and the definition of detailed operating safety procedures. A virtually infinite number of different options in terms of working conditions and modus operandi may be accurately investigated and compared in detail, in order to evaluate the most suitable solutions for eliminating or, if not possible, minimizing the risks to the workers. As far as workers’ education and training are concerned, it is well known that some particular aspects have to be considered,
M. Patrucco et al. / Safety Science 48 (2010) 508–516
because of different learning mechanism in elderly vs. younger people and the aim itself of adult education processes. In fact, the education and training of adults must give rise to theoretical knowledge, but moreover proper attitudes and subsequently practical skills that shall be applied in real situations (Knowles, 1984). First, it is fundamental that the learner totally understands the problems, in order to implement the right actions and solutions (Barrows and Tamblyn, 1980). In order to fulfill these needs, a series of teaching methodologies have been specially developed for fields where pure knowledge, practical skills, and problem solving capabilities are fundamental (e.g. medical education). In particular, these methodologies can involve case studies, small group discussions, Problem Based Learning, and so on. These methods have been proven to have their effect by the activation of previous knowledge processes and the capability to adapt the information to the specific context. Therefore, these methodologies facilitate the activation of prior knowledge and elaboration of newly acquired information, thereby enhancing the retention of knowledge (Norman and Schmidt, 1992). This being the situation, the CIGJS method can be a helpful tool also in workers’ education and training, able to resolve some difficulties that affect the construction sector. In fact, from a research study on training effectiveness in the construction field, it was also inferred that training is more effective when delivered by someone who knows the subject, has experience in the job, and is familiar with the job-specific risks (Tackett et al., 2006). According to the interviewed workers, formal training programs came out to fail in addressing the ‘‘real-life” hazards; they also emphasized that practical, hands-on knowledge and a focus on job-specific skill sets are critical to the effectiveness of the training. CIGJS stresses the importance of participation and consultation of workers, who are actively involved in the simulation process, especially when the specific task has to be analyzed and ‘‘captured” by the cameras. The final result is a realistic environment, obtained from CAD files and photographs, where real workers contributed in simulating the task, thus overcoming the traditional training problems. Finally, CIGJS, giving the opportunity to take into account the specific anthropometric characteristics of each worker, can lead to an appropriate selection of the members of the crew to which particular tasks should be committed (for instance, in case of emergencies, or where critical boundary conditions are present, as sometimes occurs in certain industrial sectors – e.g. mining).
6. Conclusion Thanks to the introduction of the computer image generation for job simulation (CIGJS) approach into the usual Job Safety Analysis (JSA) technique, a substantial improvement in the analysis capabilities both in routine conditions and in difficult situations was successfully achieved. The new JSA + CIGJS approach gives the possibility to achieve easier, faster, and much more intuitive considerations on the hazards possibly present in each working operation and on their effective control. It allows realistic simulation of the real workplaces and of the tasks actually performed by the workers, helping the Risk Analysts in their job and overcoming the JSA traditional limits. In fact, by use of JSA technique in its traditional approach, only one operation at a time may generally be considered, with no possibility of interference evaluation; also, only actual operating situations may be dealt with, because of the difficulties in the definition of scenarios not already in existence. JSA + CIGJS discloses new and interesting possibilities in the Risk Analysis and Management of new operating layouts at the very first design stage (both in normal and emergency situations), contributing effectively to a Prevention through Design (PtD) approach.
515
Thanks to a series of successful in-field tests, which confirmed flexibility, detail, and good usability, the Authors are convinced that the discussed evolution of a well-known and widely used Risk Analysis and Management technique like the Job Safety Analysis will be appreciated by the Risk Analysts and Safety Trainers, and it will substantially contribute to improve both the work efficiency and the occupational Safety and Health conditions. As a matter of fact, the method, apart from showing the actual S&H conditions, gives information on the effectiveness of the adopted countermeasures: the possibility to forecast the effect of a design improvement and to ‘‘visualize” the results of the proposed solutions represents a further improvement in the aforesaid PtD approach and a useful and intuitive tool for Risk Analysts and designers. At present, a Job Safety Analysis performed with the proposed approach has a notable cost, but the encouraging results and the decreasing trend in programming costs suggest, for the future, a wide range of useful applications suitable for the ‘‘non-major-accident hazards” industrial sectors. The JSA + CIGJS method shows interesting aspects also in the European Directives context: as regards ‘‘Council Directive 89/391/EEC of 12 June 1989 on the introduction of measures to encourage improvements in the safety and health of workers at work”, wherein it is clearly stated that the employer shall take the measures necessary for safety and health protection of the workers by ‘‘adapting the work to the individual, especially as regards the design of work places, the choice of work equipment and the choice of working and production methods, with a view, in particular, to alleviating monotonous work and work at a predetermined work-rate and to reducing their effect on health”, also ‘‘developing a coherent overall prevention policy which covers technology, organization of work, working conditions, social relationships, and the influence of factors related to the working environment”; in the eyes of the Machinery Directive that will become effective on December 29th, 2009 (Directive 2006/42/EC of the European Parliament and of the Council of 17 may 2006 on Machinery, and amending Directive 95/16/EC), where it is highlighted that the design phase should take into account not only setup, installation, intended use, maintenance, and cleaning, but also ‘‘any reasonably foreseeable misuse”. A possible future development may be found in the field of education and training of workers on correct and safe working procedures, up to a possible use as an effective simulation-training device. In fact, the choice of a 3D interface with near real-world representation allows learning-by-doing and case-based reasoning approaches, stressing the importance of participation and consultation of workers. The final result of a realistic environment where real workers contribute in simulating the task, helps to overcome the traditional training problems due to theoretical approach and lack of specificity. References Alfaro Degan, G., Pinzari, M., 2001. The functional analysis space technique (FAST) in risk analysis. In: Zio, E., Demichela, M., Piccinini, N. (Eds.) Proceedings of the European Conference ESREL 2001: Towards a Safer World, Torino, Italy, pp. 847–954, ISBN 88-8202-099-5. Arcangeli, G., Del Bimbo, A., Vicario, E., 1999. Use of virtual reality for instruction and training of young workers (European Project SAFE). Preliminary data, In: Proceedings of the ‘International Conference on Computer-aided Ergonomics and Safety’, Barcelona, Spain, pp. 1232–1239. Assfalg, J., Del Bimbo, A., Vicario, E., 2002. Using 3D and ancillary media to train construction workers, IEEE Multimedia. Barrows, H.S., Tamblyn, R.M., 1980. Problem-based Learning: An Approach ti Medical Education. Springer Publishing Company, New York. Behm, M., 2008. Rapporteur’s report construction sector. Journal of Safety Research 39 (2), 175–178.
516
M. Patrucco et al. / Safety Science 48 (2010) 508–516
Camisassi, A., Cigna, C., Patrucco, M., 2004. Sicurezza nei cantieri: analisi di rischio e condizioni di impiego in sicurezza di macchine operatrici e mezzi di sollevamento di materiali, GEAM-Geoingegneria ambientale e mineraria XLI, vol. 3, pp. 19–32. Camisassi, A., Cigna, C., Nava, S., Patrucco, M., Savoca, D., 2006. Load and hauling machinery: an evaluation of the hazard involved as a basis for an effective risk evaluation. In: Cardu, M., Ciccu, R., Lovera, E., Michelotti, E. (Eds.) Proceedings of Mine Planning and Equipment Selection (MPES 2006), Torino, Italy, pp. 395– 400, ISBN 88 901342 4 0. Chao, E.L., Henshaw, J.L., 2002. Occupational safety and health administration. Job Hazard Analysis.
Lainema, T., Nurmi, S., 2006. Applying an authentic, dynamic learning environment in real world business. Computers & Education 47 (1), 94–115. Manuele, F.A., 1997. On the practice of safety, ISBN 9780471272755. Mujber, T.S., Szecsi, T., Hashmi, M.S.J., 2004. Virtual reality applications in manufacturing process simulation. Journal of Materials Processing Technology 155–156, 1834–1838. National Occupational Health and Safety Commission. Australian Government, 2004. The role of design issues in work related injuries in Australia 1997–2002. ISBN 1 920763 32 5. Norman, G.R., Schmidt, H.G., 1992. The psychological basis of PBL. A review of the evidence. Academic Medicine 67, 557–565. Passman, M.A., Fleser, P.S., Dattilo, J.B., Guzman, R.J., Naslund, T.C., 2007. Should simulator-based endovascular training be integrated into general surgery residency programs? The American Journal of Surgery 194 (2), 212–219. Pellegrino, V., 2008. Analisi dei rischi: schede, pensieri, parole, In: Proceedings of ANIM ‘Sicurezza e tutela dell’ambiente nell’impiego di macchine operatrici e impianti mobili’ SAMOTER 08, Verona, Italy, pp. 71–80. Pfahl, D., Laitenberger, O., Ruhe, G., Dorsch, J., Krivobokova, T., 2004. Evaluating the learning effectiveness of using simulations in software project management education: results from a twice replicated experiment. Information and Software Technology 46 (2), 127–147. Regione Lombardia, 2002. Criteri per la valutazione dei rischi e la redazione del Documento di Sicurezza e Salute (DSS e DSS Coordinato) ai sensi dell’art. 6, comma 1, del decreto legislativo no. 624/1996 nel comparto estrattivo. Official Bulletin BURL 2002, no. 8, Annex 2. Salvi, O., Merad, M., Rodrigues, N., 2005. Toward an integrated approach of the industrial risk management process in France. Journal of Loss Prevention in the Process Industry 18, 414–422. Tackett, J., Goodrum, P.M., Maloney, W.F., 2006. Safety and health training in construction in Kentucky. The Center to Protect Workers’ Rights (CPWR) US Bureau of Labor Statistics, US Department of Labor, 2008. Official Statistics.