2013-10-01 12:00 - Messages

Prevention of falls to a lower level

Evaluation of an occupational health and safety intervention via subsidies for the replacement of scaffolding
The objective of this study is to evaluate the impact of a subsidy policy for construction companies in Andalusia (Spain), which enables them to acquire new scaffolds. The rate of falls from scaffolds within the Andalusian construction sector in the period 2009-2011 was analysed. A randomised controlled trial was not possible as the subsidy was granted according to a public and competitive call. A quasi-experimental design based on an intervention group (subsidised companies) and a control group was chosen. Companies in the control group were selected from the social security census of companies in order to avoid selection bias. The subsidy policy has led to an overall 71% decrease in the rate of accident involving falls to a lower level in the companies that received grants in the period 2009-2011. The confidence interval for the comparison for the before-after difference in rates between the intervention group and the control group is found significant (confidence 95%, p = 0.05). The improvement of scaffolds was effective in reducing rates of accident with falls to a lower level. This intervention should be a priority in public policies. The process of standardisation of equipment with high accident risk should be developed further.

Source : Rubio-Romero JC, Carrillo-Castrillo JA, Gibb A. Int. J. Inj. Control Safe. Promot. 2013.

NIOSH Publication Raises Respirator Awareness among Health Care Workers

A new NIOSH publication provides health care workers with information on respiratory protection products and stresses the importance of using NIOSH-approved respirators. The publication includes descriptions and images of N95 filtering facepiece respirators and surgical N95 respirators, and explains how employees can verify whether the respirators they use are genuinely certified and approved by NIOSH. The agency also lists several other resources for information on respirators, including NIOSH’s “respirator trusted-source information” page, http://KnowIts.NIOSH.gov. NIOSH reminds workers to follow the guidance of their organizations’ respiratory protection programs, get fit-tested annually, and know how to use their respirators safely and effectively.

Source : http://www.cdc.gov/niosh/docs/2013-138/default.html

Développement d'un modèle de gestion graduée du risque pour le choix de la protection respiratoire contre les bioaérosols

La sélection d'un appareil de protection respiratoire contre les bioaérosols peut s'avérer une tâche complexe compte tenu de l'absence de valeurs limites d'exposition et de données toxicologiques, ainsi que des limites des techniques d'échantillonnage actuelles et de la grande diversité des bioaérosols. Dans ces circonstances, une méthode qualitative d'évaluation et de gestion du risque fournit une alternative aux méthodes quantitatives utilisées en hygiène du travail. Ce rapport propose un modèle de gestion graduée du risque pour le choix de la protection respiratoire contre les bioaérosols infectieux et non infectieux applicable à l'ensemble des milieux de travail et s'adressant aux hygiénistes du travail et autres intervenants en santé et en sécurité du travail, ainsi qu'aux experts membres de sociétés savantes.

Source : http://www.irsst.qc.ca/-publication-irsst-developpement-d-un-modele-de-gestion-graduee-du-risque-pour-le-choix-de-la-protection-respiratoire-contre-les-bioaerosols-r-766.html?utm_source=SendBlaster&utm_medium=email&utm_term=infoirsst%2D2013%2D09%2Doct&utm_content=infoirsst%2D2013%2D09%2Doct&utm_campaign=infoirsst%2D2013%2D09%2Doct

The Effect of Air Permeability Characteristics of Protective Garments on the Induced Physiological Strain under Exercise-Heat Stress

Objectives: The high values of thermal resistance (Rct) and/or vapor resistance (Ret) of chemical protective clothing (CPC) induce a considerable thermal stress. The present study compared the physiological strain induced by CPCs and evaluates the relative importance of the fabrics' Rct, Ret, and air permeability in determining heat strain. Methods: Twelve young (20–30 years) healthy, heat-acclimated male subjects were exposed fully encapsulated for 3h daily to an exercise-heat stress (35°C and 30% relative humidity, walking on a motor-driven treadmill at a pace of 5 km h1 and a 4% inclination, in a work–rest cycle of 45min work and 15min rest). Two bipack CPCs (PC1 and PC2) were tested and the results were compared with those attained by two control suits—a standard cotton military BDU (CO1) and an impermeable material suit (CO2). Results: The physiological burden imposed by the two bilayer garments was within the boundaries set by the control conditions. Overall, PC2 induced a lower strain, which was closer to CO1, whereas PC1 was closer to CO2. Air permeability of the PC2 cloth was almost three times higher than that of PC1, enabling a better heat dissipation and consequently a lower physiological strain. Furthermore, air permeability characteristic of the fabrics, which is associated with its construction and weave, significantly correlated with the physiological strain, whereas the correlation with Rct, Ret, and weight was poor. Conclusions: The results emphasize the importance of air permeability in reducing the physiological strain induced by CPCs.

Source : Yoram Epstein, Yuval Heled, Itay Ketko, Jeni Muginshtein, Ran Yanovich, Amit Druyan, and Daniel S. Moran. Ann Occup Hyg (2013) 57 (7): 866-874. http://dx.doi.org/10.1093/annhyg/met003

Component Analysis of Respirator User Training

Respirators must be properly used to be effective. In an experimental protocol, 145 subjects were trained and then observed donning and doffing respirators. Filtering facepiece and dual cartridge half face mask types were studied. Subjects were then tested for knowledge and for proper performance using video recording analysis. Knowledge tests showed adequate learning, but performance was often poor. Inspection, strap tension (half mask), seal checking, and avoiding mask contact during doffing were particularly problematic. Mask positioning was generally well done. Correlation between knowledge and performance for specific items was generally poor, although there was a weak correlation between overall knowledge and overall performance (rho = 0.32) for the half mask users. Actual unprompted performance as well as knowledge and fit-testing should be assessed for user certification. Respirator design approval should consider users' ability to learn proper technique.

Source : Philip Harber, Robert J. Boumis, Jing Su, Sarah Barrett, Gabriela Alongi. Journal of Occupational and Environmental Hygiene, Vol. 10, No 10, 2013.  

Measuring the acoustic response of a compartment fire

Rescue teams have a small window of time to locate a downed firefighter. Their task is made more difficult due to low visibility, smoke, toxic gases, and high temperatures. In the United States, most firefighters are equipped with a Personal Alarm Safety System (PASS) device that emits an alarm sound, when the firefighter becomes incapacitated. Rescue teams can then follow this sound to the source to locate the downed firefighter. While the PASS device has been enormously successful, anecdotal evidence has shown it fails in some interesting scenarios. For example, cases have been recorded where firefighters inside the building were unable to hear the signal, whereas those outside heard it clearly. To explain these cases, and to improve the signal used by the PASS device, it is necessary to understand sound propagation in the fireground environment. This paper will present acoustic transfer measurements inside a laboratory compartment fire, simulating a fire in a residential structure. The research aims to understand how the developing temperature gradient and smoke layer influences sound propagation. A secondary goal is the development and validation of finite element models of fireground acoustics. [Work supported by U.S. Department of Homeland Security Assistance to Firefighters Grants Program.].

Source : Abbasi MZ, Wilson PS, Ezekoye OA. J. Acoust. Soc. Am. 2013; 133(5): 3500. http://asadl.org/jasa/resource/1/jasman/v133/i5/p3500_s1?bypassSSO=1

Performance Evaluation of Selected N95 Respirators and Surgical Masks When Challenged with Aerosolized Endospores and Inert Particles

The objective of this study was to assess how the relative efficiency of N95 respirators and surgical masks might vary with different challenge aerosols, utilizing a standardized manikin head form as a surrogate to human participation. A Collision nebulizer aerosolized B. anthracis Sterne strain endospores and polystyrene latex (PSL) particles to evaluate 11 models of N95 respirators and surgical masks. An automated breathing simulator, calibrated to normal tidal volume and active breathing rate, mimicked human respiration. A manikin head form with N95 respirators or surgical masks, and manikin head form without N95 respirators or surgical masks were placed in the bioaerosol chamber. An AGI-30 sampler filled with phosphate buffered water was fitted behind the mouth of each manikin head form to collect endospore bioaerosol samples. PSL aerosols concentrations were quantified by an ARTI Hand Held Particle Counter. Geometric Mean (GM) relative efficiency of N95 respirators and surgical masks challenged with endospore bioaerosol ranged from 34–65%. In PSL aerosol experiments, GM relative efficiency ranged from 35–64% for 1.3 μm particles. GM filtration efficiency of all N95 and surgical N95 respirators filter media evaluated was ≥99% when challenged with particles ≥0.1 μm. GM filtration efficiency of surgical mask filter media ranged from 70–83% with particles ≥0.1 μm and 74–92% with 1.3 μm PSL particles. Relative efficiencies of N95 respirators and surgical masks challenged with aerosolized B. anthracis endospores and PSL were similar. Relative efficiency was similar between N95 respirators and surgical masks on a manikin head form despite clear differences in filtration efficiency. This study further highlights the importance of face seal leakage in the respiratory protection provided by N95 respirators, and demonstrates it on a human surrogate.

Source : Craig S. Davidson, Christopher F. Green, Shawn G. Gibbs, Kendra K. Schmid, Adelisa L. Panlilio, Paul A. Jensen, Pasquale V. Scarpino. Journal of Occupational and Environmental Hygiene, Vol. 10, no 9, 2013. http://dx.doi.org/10.1080/15459624.2013.818243

endospores, filtration efficiency, inert particles, N95, relative efficiency, surgical mask

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