In search of a performing seal: rethinking the design of tight-fitting respiratory protective equipment facepieces for users with facial hair

Background: Air-purifying, tight-fitting facepieces are examples of respiratory protective equipment and are worn to protect workers from potentially harmful particulate and vapors. Research shows that the presence of facial hair on users' face significantly reduces the efficacy of these devices. This article sets out to establish if an acceptable seal could be achieved between facial hair and the facepiece. The team also created and investigated a low-cost "pressure testing" method for assessing the efficacy of a seal to be used during the early design process for a facepiece designed to overcome the facial hair issue. Methods: Nine new designs for face mask seals were prototyped as flat samples. A researcher developed a test rig, and a test protocol was used to evaluate the efficacy of the new seal designs against facial hair. Six of the seal designs were also tested using a version of the conventional fit test. The results were compared with those of the researcher-developed test to look for a correlation between the two test methods. Results: None of the seals performed any better against facial hair than a typical, commercially available facepiece. The pressure testing method devised by the researchers performed well but was not as robust as the fit factor testing. Conclusion: The results show that sealing against facial hair is extremely problematic unless an excessive force is applied to the facepiece's seal area pushing it against the face. The means of pressure testing devised by the researchers could be seen as a low-cost technique to be used at the early stages of a the design process, before fit testing is viable

Exposure to Airborne Asbestos in Jamaican Hospitals

Objective: Asbestos is an established human carcinogen and has been identified at 16 of 26 Jamaican hospitals surveyed. We sought to determine if hospital employees are exposed and if current asbestos exposure in Jamaican hospitals differed by job category. Method: At two of the largest hospitals with more than 10 permanent maintenance workers and where over 67% of bulk samples analysed contained asbestos, three groups of employees selected by stratified random sampling participated in a personal air sampling study for asbestos. One hundred and thirtytwo personal air samples and 32 area samples were collected and analysed for asbestos fibres utilizing phase contrast microscopy (PCM) and transmission electron microscopy (TEM). Results: Twenty-four (14.6%) air samples had fibre counts above the limit of detection (LOD) for the analytical method (PCM), ranging from 0.002 f/cc to 0.013 f/cc. The fibres met the dimensional characteristics of asbestos fibres. There was no difference in the median fibre concentration to which the groups of employees were exposed. Further testing of samples which had fibre counts above the LOD using TEM confirmed that the fibres were not asbestos. Conclusion: Despite not finding asbestos fibres in the air samples, most of the asbestos containing building material (ACBM) found in the hospitals was friable and in a poor condition indicative of fibre release. We recommend an ongoing monitoring programme for airborne asbestos fibres in hospitals until an abatement programme can be undertaken by the regulatory agencies in the country. Keywords: Asbestos, exposure, Jamaican hospitals, personal air sampling "Exposición al Asbesto Suspendido en el Aire en Hospitales de Jamaica" RESUMEN Objetivo: El asbesto, también llamado amianto, es un carcinógeno humano conocido, y ha sido identificado en 16 de 26 hospitales jamaicanos investigados. El presente trabajo tuvo por objeto determinar si los empleados del hospital están expuestos al asbesto, y si la exposición actual de asbesto en hospitales jamaicanos difiere según la categoría del trabajo. Método: En dos de los hospitales más grandes con más de 10 obreros de mantenimiento permanentes y dónde más del 67% de las muestras a granel analizadas contenían asbesto, tres grupos de empleados seleccionados por muestreo aleatorio estratificado participaron en una investigación de muestreo de aire personal en busca de asbesto. Ciento treinta y dos muestras de aire personal y 32 muestras de área fueron recogidas y analizadas en busca de fibras de asbesto, utilizando microscopía de contraste de fases (MCF) y microscopía electrónica de transmisión (MET). Resultados: Veinticuatro (14.6%) muestras de aire tuvieron un conteo de fibras por encima del límite de detección (LDD) para el método analítico (MCF), que fluctuaba de 0.002 f/cc a 0.013 f/cc. Las fibras correspondían a las características dimensionales de las fibras de asbesto. No hubo diferencias en la concentración mediana de las fibras a la que los grupos de empleados estaban expuestos. Pruebas posteriores con las muestras que arrojaron conteos de fibras por encima del LDD usando la MET, confirmaron que las fibras no eran de asbesto. Conclusión: A pesar de que no se encontraron fibras de asbesto en las muestras de aire, la mayor parte de los materiales de construcción que contienen asbesto (ACBM) hallados en los hospitales eran friables y estaban en mal estado, dando ya señales de desprendimiento de fibras. Se recomienda un programa de monitoreo de fibras de asbesto suspendidas en el aire en los hospitales hasta que pueda emprenderse un programa de eliminación de las mismas por parte de las agencias reguladoras del país. Palabras claves: Asbestos, exposición, hospitales de Jamaica, muestreo de aire persona

Evaluation of the Exposure Prediction Component of Control of Substances Hazardous to Health Essentials

© 2020, © 2020 JOEH, LLC. The exposure prediction component of the Control of Substances Hazardous to Health (COSHH) Essentials model (paper version) was evaluated using field measurements from National Institute of Occupational Safety and Health (NIOSH) Health Hazard Evaluation (HHE) reports. Overall 757 measured exposures for 94 similar exposure groups (SEGs) were compared with the COSHH Essentials predicted exposure range (PER). The SEGs were stratified based on the magnitude of measured exposures (high, medium, or low) and physical state of the substance (vapor or particulate). The majority of measured exposures observed involved low-level exposure to vapors; thus, overall findings from the current study are limited to low-level vapor exposure scenarios. Overall, the exposure prediction component of COSHH Essentials vastly overestimated low-level exposures to vapors. This study went beyond the scope of previous studies and investigated which model components led to the overestimation. It was concluded that COSHH Essential’s tendency to overestimate was due to multiple complex interactions among model components. Overall, the magnitude of overestimation seems to increase exponentially as values for predictor variables increase. This is likely due to the log-based scale used by the model to allocate concentration ranges. In addition, the current banding scheme used to allocate volatility appears to play a role in the overestimation of low-level exposures to vapors