Documents visibility 11 results

"A survey carried out by the ‘Caisse Nationale d'Assurance Maladie' (French National Insurance Fund) on serious and fatal accidents in which earth-moving machines were implicated showed that one third of these accidents were due to insufficient driving visibility. A draft standard to define visual at the operator's position based on the projected shadows method was submitted to ISO. The ISO test method has been applied to 15 different hydraulic excavators. At the same time, INRS (National Institute of Research and Safety) worked out a novel approach based on photography of the visual field and applied it to the 15 hydraulic excavators in the same conditions. The purpose of this study is to compare the results and disadvantages of the two approaches for controlling applicability of the ISO Standard draft to hydraulic excavators. There is no correlation between the two techniques at all concerning front visibility, which indicates that the ISO draft is deficient. It only analyses one circular line rather than the full surface, which should be the more valid approach."

"La cabine est un constituant essentiel qui doit permettre à l'opérateur de travailler en toute sécurité et de préserver sa santé. Elle doit en particulier le protéger contre les vibrations, les risques de retournement et de basculement, les risques de chutes et de collisions avec les piétons ou encore les nuisances de l'environnement. L'employeur-utilisateur doit fournir à ses employés des machines équipées en fonction des tâches à réaliser et de l'environnement de travail."

"Une mention de mise en garde concernant la norme EN 474-1 sur la sécurité de ces engins a été publiée au Journal officiel de l'Union européenne (JO du 8 janvier 20151). De ce fait, la présomption de conformité de cette norme ne s'applique plus aux exigences de la directive " Machines " concernant la visibilité depuis le poste de conduite. À la suite d'une recommandation sur la surveillance du marché européen, il a parallèlement été décidé de modifier à court terme la norme ISO 5006 (visibilité du conducteur sur les engins de terrassement)."

"La prévention des collisions entre des engins mobiles et des piétons est une problématique qui concerne différents secteurs d'activité : BTP, manutention, collecte des déchets, transport/logistique notamment. Dans chacun d'eux, le problème potentiel de la collision se pose dès lors qu'il existe une proximité entre l'homme et les engins mobiles. Après avoir défini ce que l'on entend par "visibilité", cet article montre, dans un premier temps, en quoi cette caractéristique est un élément essentiel pour la prévention des collisions engins-piétons. Dans un second temps, les approches réglementaires et normatives applicables aux engins de terrassement, aux chariots de manutention et aux camions de transport sont présentées puis discutées au regard d'une analyse bibliographique sur ce sujet. Il est ainsi mis en évidence qu'elles ne prennent pas suffisamment en compte l'activité visuelle des conducteurs dans toutes les situations de travail possibles. Afin de pallier ces limites, de nombreux travaux proposent des méthodologies d'évaluation basées sur des équipements de mesure de plus en plus évolués au fil du temps, cependant peu abordent la définition des critères de performance. D'autres travaux portent sur le développement et l'évaluation de solutions techniques visant à mettre en adéquation la visibilité offerte par un engin à son contexte d'utilisation. Les rétroviseurs et les miroirs sont depuis longtemps utilisés à cet effet et l'on constate que les systèmes caméras-écrans prennent une part de plus en plus importante dans ce domaine. Si plusieurs études montrent l'intérêt potentiel de ces dispositifs, d'autres en soulignent les limites, notamment du point de vue cognitif : difficulté pour un conducteur de distribuer simultanément son attention sur plusieurs sources d'information."

"In this experiment all panels had four circular displays arranged in a square on a vertical surface and four controls aligned vertically to the right of the displays. Two panels had linkages between controls and displays which earlier research had shown to be compatible, the other two had incompatible linkages. Each of these four panels was tested with and without sensor lines showing the linkages between controls and displays. Ninety-six subjects each made 128 trials on one of the eight panels. A subject's task was to respond as quickly as possible by pushing the correct control to extinguish a light when it appeared in one of the displays. Sensor lines had no effect on performance with the compatible panels but impaired performance on the incompatible panels. The results also confirm again the potency of the compatibility principle: responses were faster and fewer errors were made when using the compatible panels."

This study investigated the differences between conditions of full face-piece respirator wear and no respirator wear over 9 h on subject ability to detect stimuli dispersed throughout the visual field. Signal detection was assessed at the beginning of each trial and after 1, 3, 5, 7 and 9 h of testing in six male and three female subjects by measuring response times to 32 randomly presented stimulus lights located within a perimeter designed specifically for this purpose. Average reaction time increased with greater peripheralization of the light signals within each experimental condition. Group mean reaction time for each peripheral ring of stimuli (12, 38, 64 and 90) showed that impairments were significantly greater for the respirator wear condition compared with the control condition at all peripheral stimulus locations. For the unmasked condition, female subjects demonstrated significantly faster response times than males at peripheral stimulus locations of 12 (p < 0.002), 64 ( p < 0.001), and 90 (p < 0.01). However, respirator wear resulted in comparable response times between sexes for each peripheral stimulus ring with the exception of stimuli located 12 from the perimeter's centre. No progressive effect of respirator wear on signal detection capability over the duration of the test was observed, suggesting that the degradation of signal detection capability caused by full face-piece respirator wear occurs immediately and persists throughout the period of wear. The findings of this study emphasize that decreased operational effectiveness in situations requiring full face-piece respirator wear should be expected.

"All municipalities in Sweden offer their inhabitants a service for disposing of large-size and hazardous waste at local recycling centres. Opening hours at these centres include hours of darkness. The aims of this study were to 1) describe user and employee experiences of lighting and signs at Swedish recycling centres, 2) measure and assess the lighting system at the two recently built recycling centres in Linköping and to assess the legibility and visibility of the signs used and 3) propose recommendations regarding lighting and signs for recycling centres. Interviews and questionnaires were used to assess experiences of employees and users, and light measurements were performed. By observing users, activities with different visual demands at different areas within the recycling centres were identified. Based on the literature, standards and stakeholder experiences, recommendations regarding lighting systems and sign design, illuminance, luminance and uniformity are proposed for recycling centres."

"A medium-sized Load-Haul-Dump (LHD) mining vehicle was evaluated using visibility tools in a computer simulation environment. The line-of-sight (LOS) available to the operator of a medium-sized LHD was calculated and displayed in a boxplot. Severe LOS restrictions were observed to several areas around the vehicle. A modified LHD design, aimed at improving LOS resulted in a marginal improvement in driver LOS (20-36%). Secondary viewing systems have not been widely accepted in the mining industry but several potential locations can be easily evaluated using computer simulation. This paper tested three camera locations for their ability to increase LOS to areas around the LHD vehicle that were very difficult to see from the operator's position. All camera locations were able to significantly improve LOS to 60% or greater while combinations of forward-facing and rear-facing cameras could improve LOS by as much as 80%."