Production and Systems

In industrial environments, it is very likely to find several workers sharing the same workplaces and being exposed to the same noise pressure levels, who have different perceptions of the risks they are exposed to. These different perceptions could lead to different workers' ...

Objectives: Although hearing protectors must be used as a temporary solution, their choice should take into account several aspects, such as ergonomic features, associated with this device. The present study aims to analyse the relationship between the acoustical attenuation efficiency and other aspects related to the comfort afforded by hearing protectors and, consequently, their acceptability when used in industrial noisy environments.

Children spend about five hours per day sitting down while doing their school work. Considering this as well as the potential inadequate use of school furniture, it is likely that some anatomical-functional changes and problems in the learning process may occur. The aim of this study was to compare furniture sizes within three different schools with the anthropometric characteristics of Chilean students in the Valparaíso region, in order to evaluate the potential mismatch between them. The sample consisted of 195 volunteer students (94 male, 101 female) of the 8th grade, ranging from 12.5 to 14.5 years of age from 3 different schools. Regarding the methodology, 6 anthropometric measures (Stature, Popliteal height, Buttock-popliteal length, Elbow height while sitting, Hip width, Thigh thickness and Subscapular height) were gathered, as well as 8 dimensions from the school furniture. For the evaluation of classroom furniture a match criterion equation was defined. After considering the existing classroom furniture dimensions in each match criterion equation, the anthropometric characteristics of the considered population were compared in order to determine the mismatch between them. Results indicated that seat height, which should be considered as the starting point for the design of classroom furniture, was appropriate for students' popliteal height in only 14% of the 2 out of the 3 schools, and 28% in the third. Seat to desk height was too high and mismatched 99% of the students in one school and 100% in the others. Therefore, it was possible to conclude that the classroom's furniture was inadequate in almost all the analyzed cases and subjects. It is possible that the high mismatch percentage found between furniture and students' anthropometry can be associated to the fact that the acquisition and selection of the furniture was made without any ergonomic concern or criteria.

The current work can be seen as a starting point for the discussion of the problematic on risk acceptance criteria in occupational environments. Some obstacles to the quantitative acceptance criteria formulation and use were analyzed. A look to the long tradition of major hazards accidents was also performed. This work shows that organizations can have several difficulties in acceptance criteria formulation and that the use of pre-defined acceptance criteria in risk assessment methodologies can be inadequate in some cases. It is urgent to define guidelines that can help organizations in the formulation of risk acceptance criteria for occupational environments.

The mismatch between students and school furniture is likely to result in a number of negative effects, such as uncomfortable body posture, pain, and ultimately, it may also affect the learning process. This study's main aim is to review the literature describing the criteria equations for defining the mismatch between students and school furniture, to apply these equations to a specific sample and, based on the results, to propose a methodology to evaluate school furniture suitability. The literature review comprises one publications database, which was used to identify the studies carried out in the field of the abovementioned mismatch. The sample used for testing the different equations was composed of 2261 volunteer subjects from 14 schools. Fifteen studies were found to meet the criteria of this review and 21 equations to test 6 furniture dimensions were identified. Regarding seat height, there are considerable differences between the two most frequently used equations. Although seat to desk clearance was evaluated by knee height, this condition seems to be based on the false assumption that students are sitting on a chair with a proper seat height. Finally, the proposed methodology for suitability evaluation of school furniture should allow for a more reliable analysis of school furniture.

The acceptance criteria are important to the decision on the risk, however, it is possible to recognize that there is a lack of guidelines to use in acceptance criteria definition. Considering that previous publications concerning the acceptance criteria definition in the occupational area are lacking, this paper aims to analyze how risk acceptance criteria can be formulated, exemplifying with an specific case in a Portuguese furniture industry. It was explore the problematic on the acceptance criteria and the principles for its formulation. The metrics to be adopted were also analyzed. Faced with the lack of guidelines for the risk acceptance criteria formulation for traditional occupational accidents, the experience with major accident hazards may help to understand some features. The principle ALARP was seen as an interest approach to use in occupational accidents. The literature review allowed find seven steps for the quantitative acceptance criteria formulation. These steps were applied on a small Portuguese furniture industry. The case study showed that the quantitative acceptance criteria formulation is not an easy process. The principle ALARP it was considered suitable to be applied. Regarding to the risk measures, the LTI-rate was the measure considered more appropriate. The upper risk acceptance limits, defined for this company, were 0.450 and 0.225 for tolerability and acceptability, respectively. The manager and consultant considered the use for the quantitative acceptance criteria as an added value to support the risk decisions. This paper showed the importance of the risk acceptance criteria in risk decisions, and exemplified how that can be done. However, this work suggests that there is still much work to be done in this area, in order to get that the companies of this sector being able to define the acceptance criteria in an equity perspective. So, it is only the first step, needing to be continued and extended to other industries.

In order to create safer schools, the Chilean authorities published a Standard regarding school furniture dimensions. The aims of this study are twofold: to verify the existence of positive secular trend within the Chilean student population and to evaluate the potential mismatch between the anthropometric characteristics and the school furniture dimensions defined by the mentioned standard. The sample consists of 3078 subjects. Eight anthropometric measures were gathered, together with six furniture dimensions from the mentioned standard. There is an average increase for some dimensions within the Chilean student population over the past two decades. Accordingly, almost 18% of the students will find the seat height to be too high. Seat depth will be considered as being too shallow for 42.8% of the students. It can be concluded that the Chilean student population has increased in stature, which supports the need to revise and update the data from the mentioned Standard.

In spite of the importance of anthropometric data, namely in what concerns the design of machinery safety devices and protective equipment, there is not as yet an extended and validated database of anthropometric measures for adult Portuguese population. The study described here consists of the development of a procedure for data acquisition and of an anthropometric database for Portuguese adult workers. Eight hundred and ninety-one individuals were measured-399 female and 492 male, with ages ranging from 17 to 65 years old. A set of 24 static anthropometric measures plus body weight was obtained for each individual. Results of the pilot study undertaken and the practical application of the procedure suggest that this is a valid one for anthropometric data acquisition. Additionally, the statistical analysis carried out to the data show that some statistical parameters, such as the variation and correlation coefficients, behave as expected, and as observed in other populations.

This paper aims at analysing the impact resulting from the adoption of different strategies for assessing workers' occupational noise exposure. With this purpose, several industrial workplaces were selected, based on the variability of the exposure time and the tasks' duration. Noise exposure assessment was made using the three strategies proposed in ISO 9612:2009, and computing the corresponding daily exposure level and associated uncertainty. The results obtained showed that the strategies recommended by that standard for each specific case represented the lowest time-consuming ones, both considering the preparation and measurement times and, with few exceptions, also led to lower values for the associated expanded uncertainty. This is particularly true in fixed workstations or in workplaces with predictable work patterns. However, if the selection was exclusively based on uncertainty values, it can be questionable whether there is room for the application of the JBM strategy, or, alternatively, if it is more straightforward to opt always for the FDM strategy, as the experimental procedures are simpler (even if the measuring time is longer). Ultimately, the present work is a contribution towards improving the measurement procedure for the assessment of occupational daily noise exposure. Relevance for industry: The assessment of the occupational noise exposure is a complex and timeconsuming process, but it can be improved if the correct measurement strategies, for each case, are adopted.

The aim of the present study was to analyse the adequacy of hearing protection devices (HPDs) by applying and comparing different methods for the estimation of effective exposure levels. This comparison involved the attenuation data of 50 HPDs (ear muffs and ear plugs), as well as 11 types of noise spectra and 4 methods. The application of the several methods considered and the comparison of the obtained estimations seem to demonstrate that there are significant differences between effective exposure levels estimated with the different methods analysed.

The current study aims at analysing the perception and opinions of people exposed to Wind Turbine (WT) noise. Noise measurements were carried out in a wind farm in the north of Portugal. Data were analysed and crossed with the answers to a survey applied in four nearby villages. Although the noise levels were generally low, it was found that the direct visibility of the WT makes people feel more annoyed and also more sensitive to noise. Finally, it seems that the economic interests that exposed people may have in WT did not significantly affect their annoyance. Noise annoyance perception rather seems to be related to specific aspects, such as the general opinion of people about wind power generation.

Integrated management systems (IMS) widespread among companies due to the release, by international entities, of management sub-systems implementation standards. The integration level achieved by the IMS varies from company to company. Rating the integration level is crucial information. Maturity models have been implemented in several business, product development and in management sub-systems context in order to guide the company to an ultimate excellence level. An IMS maturity model development is, currently, aimed by researchers and a real need in companies. It is intended in this paper to report the efforts that are being made and the methodologies that are being followed to develop such a model. Additionally, it is also intended to present a preliminary model version.