Respiratory protection - 688 entries found
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Louhevaara V., et al.
Maximal physical work performance with European standard based fire-protective clothing system and equipment in relation to individual characteristics
The aim of this study was to quantify the effects of fire-protective clothing designed to fulfil European standard EN 469 used over standardized (Nordic) clothing and a self-contained breathing apparatus (SCBA) on maximal physical work performance. Twelve healthy firemen aged 26-46 years were examined. The maximal tests without (control) and with the fire-protective clothing system and SCBA were carried out on a treadmill in a thermoneutral environment. When compared to the control test, the decrease in the maximal power output in terms of maximal working time and walking speed averaged 25%, varying from 18% to 34% with the fire-protective clothing system and the SCBA. At maximum, no significant differences were found in pulmonary ventilation, absolute oxygen consumption, the respiratory exchange ratio, heart rate, systolic blood pressure, the rate-pressure product, mechanical efficiency and the rating of perceived exertion between the tests with and without the tested equipment. The reduction in power output was related to the extra mass of the fire-protective clothing and the SCBA. In physically demanding fire fighting and rescue work all possible means to decrease the mass of both the protective clothing and SCBA need to be considered for maintaining sufficient power output.
European Journal of Applied Physiology and Occupational Physiology, 1995, Vol.71, p.223-229. Illus. 21 ref.
OSHA's Respiratory Protection Standard: A proven written program for compliance
Pre-written programme that can be adapted for the development of a safety management programme within the enterprise in order to comply with the OSHA standard. Complete text of the OSHA Standard is included.
Government Institutes, 4 Research Place, Rockville, MD 20850, USA, 1995. Computer diskette (text in WordPerfect) + manual (88p.). Price: USD 59.00. ###
Protect yourself against tuberculosis - A respiratory protection guide for health care workers
Training guide on the prevention of tuberculosis among health-care workers (primarily, nurses). Contents: basic information on tuberculosis, a disease that is again spreading in the US; use of respirators as a means of prevention; use and certification of respirators; types of respirators; respirator programmes (training, fitting, maintenance); frequently asked questions and their answers. In appendix: required respirator programme elements (check list).
National Institute for Occupational Safety and Health, Publications Dissemination, 4676 Columbia Parkway, Cincinnati, OH 45226-1998, USA, Dec. 1995. vi, 25p. Illus. Bibl.ref.
Review: Activated carbon filters in respiratory protective equipment
This review describes the behaviour of activated carbon filters in respirators providing personal protection against gases and vapours. Topics covered include: airflow through granular carbon filters and the relationship between pressure drop and airflow rate; equilibrium adsorption theory; adsorption dynamics; analytical solution of the fundamental dynamic adsorption equation and development of equations for the description of breakthrough; adsorption of specific compounds and of mixtures; effect of humidity on the performance of activated carbon; desorption; odour detection; performance tests; future research.
International Journal of Occupational Safety and Ergonomics, 1995, Vol.1, No.4, p.330-373. Illus. 165 ref.
Johnson A.T., Dooly C.R., Dotson C.O.
Respirator mask effects on exercise metabolic measures
American Industrial Hygiene Association Journal, May 1995, Vol.56, No.5, p.467-473. Illus. 29 ref. ###
Introduction to respiratory protection
Grundlagen des Atemschutzes [in German]
Contents of this introduction to respiratory protection: physiology of the respiratory system; toxic substances; respiratory protection in general (including standards for respiratory equipment EN 133 and for masks EN 136); filter and self-contained breathing apparatus; when should respiratory protection equipment be used; training of users; maintenance and care.
W. Kohlhammer Druckerei GmbH & Co., 70549 Stuttgart, Germany, 1995. 158p. Illus. 30 ref. Index. Price: DEM 38.00.
Villa M., Hubert G., Lima S., Kauffer E., Héry M.
Asbestos removal in an office building - Efficacy of personal protection
Opérations de désamiantage dans un immeuble de bureaux - Efficacité de la protection individuelle [in French]
Workplace protection factors (WPFs) were determined for a powered respiratory protective device using four different power units in succession during the removal of sprayed asbestos in an office building. The test subjects concerned wore clothing specially designed for airtightness at the arm, leg and neck joints. The paper describes working conditions, WFP determination methods and difficulties encountered: asbestos removal methods, decontamination, air sampling (duration, flow variation, filter installation). All exposure levels measured were below the chrysotile limit value. The most conclusive test results were obtained with a power unit that gave WPFs of between 400 and 10,000, most readings being in excess of 3,000. The study highlights the importance of the right personal protection for the working conditions concerned, but no explanation was found for the poorest efficiency levels: the test procedure was identical in every case and no particular incidents were reported.
Cahiers de notes documentaires - Hygiène et sécurité du travail, 4th Quarter 1995, No.161, Note No.2002-161-95, p.463-467. Illus. 9 ref.
Turner N., Beeckman D., Hodous T.
Evaluation of proposed methods to update human testing of self-contained breathing apparatus
Proposed use test protocols for the human testing of self-contained breathing apparatus (SCBA) were evaluated. Unlike the current NIOSH tests, the proposed tests use a continuous monitoring technique and provide the ability to test apparatus at consistent absolute work rates regardless of the body weight of the subject. The proposed tests were evaluated for four different SCBAs worn by seven subjects in three body weight categories. The proposed test protocols could form the basis for eventual recommendations to revise the current tests for SCBA performance evaluation.
American Industrial Hygiene Association Journal, Dec. 1995, Vol.56, No.12, p.1195-1200. Illus. 16 ref.
The assigned protection factor of 10 for half-mask respirators
Studies on the performance of half-mask air purifying respirators were analyzed. Using data from seven selected studies, 1.5% of the workplace protection factor (WPF) values were less than 10, the best estimate of the fifth percentile was 13, with a 95% confidence interval of 10 to 18. This appears to support the assigned protection factor of 10 for this class of respirators. Differences between the mean WPF based on the type of filter were found, but no difference was found between the mean performance of elastomeric and disposable respirators equipped with dust/mist and dust/fume/mist filters.
American Industrial Hygiene Association Journal, July 1995, Vol.56, No.7, p.717-724. Illus. 29 ref.
Mullins H.E., Danisch S.G., Johnston A.R.
Development of a new qualitative test for fit testing respirators
A qualitative fit test was developed using Bitrex¿ (denatonium benzoate) as the test agent. It was validated by running a series of paired fit tests on subjects wearing NIOSH-approved half mask respirators fitted with high efficiency filters. Quantitative tests were conducted with a small corn oil aerosol. Qualitative fit tests were run with Bitrex and saccharin, following the established protocol for the saccharin fit test. The Bitrex and saccharin tests were found to have virtually the same performance. Bitrex is a good alternative to consider for qualitative fit testing.
American Industrial Hygiene Association Journal, Nov. 1995, Vol.56, No.11, p.1068-1073. Illus. 27 ref.
Respiratory protection and the risk of Mycobacterium tuberculosis infection
Several types of respirator were compared with respect to efficacy against penetration of infectious droplet nuclei capable of carrying Mycobacterium tuberculosis bacilli. Powered air-purifying respirators (PAPRs) with elastomeric halfmask facepieces and high efficiency (HEPA) filters provided substantially better protection than did surgical masks and disposable dust/mist particulate respirators. This greater protection is related to the PAPR's relatively high filtration efficiency and the low degree of facial leakage. When droplet nuclei source control is inadequate, healthcare workers may need to wear highly protective respirators for protection against tuberculosis infection.
American Journal of Industrial Medicine, Mar. 1995, Vol.27, No.3, p.317-333. 38 ref.
Thomas M.L., Cohen B.S.
A simple method for vapor dosing of charcoal sorbent tubes
A method for vapour-dosing of charcoal sorbent tubes that does not require the expense and effort of a test chamber was used to test the desorption efficiency of seven solvent vapours. The experimental system consisted of a loaded filter cassette connected directly to a charcoal sorbent tube. Vapour was generated by injecting liquid solvent onto the glass fibre filter and drawing air through the system. The solvent was desorbed from the filter and charcoal for analysis. The measured desorption efficiencies were similar to those reported for liquid dosed charcoal. The method is suitable for low solvent concentrations (0.2 to 10ppm).
American Industrial Hygiene Association Journal, Jan. 1995, Vol.56, No.1, p.70-73. Illus. 9 ref.
Crutchfield C.D., Park D.L., Hensel J.L., Kvesic M.K., Flack M.D.
Determinations of known respirator leakage using controlled negative pressure and ambient aerosol QNFT systems
A study was carried out to assess how well a controlled negative pressure (CNP) fit-test system and an ambient aerosol fit-test system could measure known sources of leakage into a respirator. In repeated measurements of respirator fit for five subjects, the CNP system's measurements of leakage averaged 105% of the known leakage rate (mean coefficient of variation 10%). The ambient aerosol system detected an average of 21% of the known leakage (mean coefficient of variation 62%). The CNP system measurements were substantially more accurate than those reported by the ambient aerosol system.
American Industrial Hygiene Association Journal, Jan. 1995, Vol.56, No.1, p.16-23. Illus. 18 ref.
Johnson A.T., Dooly C.R., Blanchard C.A., Brown E.Y.
Influence of anxiety level on work performance with and without a respirator mask
Twenty subjects were tested for trait anxiety levels and performed on a treadmill at 80-85% of their maximum heart rates until they reached voluntary end-point. Physiological, metabolic and subjective measurements were taken every minute. While there was extreme variability in subject responses, performance times with the mask averaged less than without the mask. Anxious subjects experience more discomfort, perform for shorter times, and accomplish less total work than their lower anxiety counterparts, even when rate of work can be adjusted.
American Industrial Hygiene Association Journal, Sep. 1995, Vol.56, No.9, p.858-865. Illus. 21 ref.
Health and Safety Executive
Respiratory protective equipment - Legislative requirements and lists of HSE approved standards and type approved equipment
This guidance document describes legislative requirements for respiratory protective equipment in the United Kingdom. Approved standards are listed and approved equipment is listed according to type. Addresses of manufacturers and suppliers are also provided. Replaces previous edition (See CIS 92-2012).
HSE Books, P.O. Box 1999, Sudbury, Suffolk CO10 6FS, United Kingdom, 4th ed., 1995. iii, 94p. Price: GBP 5.50.
Durand K.T.H., Egilman D.S.
The DuPont Imron® studies: An example of possible misrepresentation of data in the industrial hygiene literature
Opinion article (not peer reviewed) commenting on a 1985 article by Vasta J.F. in the same journal ("Respirator cartridge evaluation for isocyanate containing Imron® and Cantari® enamels", see CIS 85-785). It is claimed that the original article contained intentionally misleading information suggesting that air-purifying respirators provided adequate protection against isocyanate-based paints (data suggesting the opposite are claimed having been suppressed). The manufacturer employing the researcher in question stood to gain significantly from results supporting this hypothesis. The Editor's comments preceding the article discuss the ethical issues involved. The rebuttal by Krivanek N.D. (p.826-829) defends the integrity of the original research article and its author and questions the motives of the authors of the present article.
American Industrial Hygiene Association Journal, Aug. 1995, Vol.56, No.8, p.817-825. 33 ref. Editor's comments, p.815-816; rebuttal on p.826-829.
Caretti D.M., Bay-Hansen L.A., Kuhlmann W.D.
Cognitive performance during respirator wear in the absence of other stressors
In order to assess the effects of respirator wear on cognitive performance, 12 men and 5 women volunteers were subjected to two (with and without wearing a respirator) 3.5h sessions of computer-controlled testing of their reaction time, decision-making and response accuracy. The anxiety levels of the subjects were also assessed. There were no significant differences in reaction time and response accuracy between the respirator and control trials. However, mean decision-making times were significantly faster during respirator wear than during the control tests. Respirator use probably increases mental function arousal and improves focussing of attention by excluding peripheral visual stimuli. The results suggest that respirator use over a relatively short period of time does not inhibit cognitive function.
American Industrial Hygiene Association Journal, Aug. 1995, Vol.56, No.8, p.776-781. Illus. 24 ref.
Myers W.R., Zhuang Z., Nelson T., Sides S., Wilmes D.
Field performance measurements of half-facepiece respirators - Study protocol
This article presents the research protocol used for a series of field studies that were conducted to measure workplace protection factors (WPF) for elastomeric and disposable half-facepiece respirators against particulate contaminants. The field studies were conducted at foundries, an aircraft painting workshop and a steel mill. The protocol involves (1) collection of WPF samples at different parts of the shift; (2) collection of respirable dust samples; (3) washing of sample cassettes; (4) use of proton-induced X-ray emission analysis. WPF results after several hours of respirator use were generally higher than just after it was put on, but not significantly so. WPF estimation might be erroneous when respirable and total dust collection techniques are mixed. Data from cassette washing suggest that average wall losses for ambient and in-facepiece samples were <2% and ca. 6%, respectively. In appendix: notes on the selection of exposure agents, facilities, workers and respirators; respirator inspection and use; analytical and cassette washing methods used.
American Industrial Hygiene Association Journal, Aug. 1995, Vol.56, No.8, p.765-775. Illus. 16 ref.
Protection against dust by respirators
A brief review is presented of the mechanism of action of fibrous filters and of the performance of respirators. Topics covered: filters used against aerosols; air flow patterns through filters and calculation of pressure drop; particle capture mechanisms and measurement of filtration efficiency; types of electrically charged filter materials and their method of action; deterioration of filters during use; types of respirators; leakage of air and particles through respirator leaks.
International Journal of Occupational Safety and Ergonomics, 1995, Vol.1, No.1, p.14-28. Illus. 53 ref.
Problems for gas absorption by gas mask canisters and cartridges
Bōdoku masuku kyūshūkan ni okeru gasu kyūchaku no mondai ten [in Japanese]
In Japan, there are two safety codes for gas-removing respirators and gas mask canisters: Japan Industrial Standard (JIS) T8152 and the safety code of the Ministry of Labour (MoL). The MoL code was established later than the JIS code, as a simplified standard comparable to foreign ones. The MoL code reduced the number of test materials, deleted numerical criteria for structural criteria such as field of view, and simplified test conditions for air-flow resistance. Current topics under study are the distribution of service lives of canisters and cartridges from one lot of articles, and the usefulness of changes in weight of canisters or cartridges for estimating breakthrough times. New respirators for protection against toxic gases used in semiconductor manufacture are needed, as are sensors for breakthrough detection.
Journal of ISRP Japan Section - Respiratory Protection, Dec. 1994, Vol.9, No.2, p.5-13. Illus. 9 ref.
Hodous T.K., Coffey C.C.
The role of respiratory protective devices in the control of tuberculosis
This comprehensive review describes various types of respirators and the major issues in their application to TB control, including the degree of protection they offer and cost. Recent recommendations regarding the use of respiratory protective devices also are discussed.
Occupational Medicine: State of the Art Reviews, Oct.-Dec. 1994, Vol.9, No.4, p.631-657. Illus. 83 ref.
Lo W., Levine S.P.
Chinese-language labeling of cartridges for air-purifying respirators
Cartridges for air-purifying respirators almost always have a label printed in English only. Therefore, non-English speakers may be at a disadvantage in the correct application of these cartridges. This brief article contains packaging recommendations for manufacturers of personal protective equipment. A sample label in English for a chemical cartridge with the proposed Chinese-language translation is included.
Applied Occupational and Environmental Hygiene, Dec. 1994, Vol.9, No.12, p.961.
Design, formation and production of personal protective equipment [Norway]
Konstruksjon, utforming og produksjon av personlig verneutstyr [in Norwegian]
Directive on the Norwegian requirements pertaining to personal protective equipment. It is harmonized with European directives 89/686/EEC (CIS 90-381), 93/95/EEC (CIS 94-778) and 93/68/EEC (CIS 94-751); it came into force 19 Aug. 1994. Procedures for evaluation of compliance and marking are described. The requirements cover the performance of the equipment, and are of a general nature. Examples of equipment dealt with are: protection against falls, hearing protection, vibration protection, protection against heat and cold, protection against drowning, protection against radiation, protection of respiratory organs, protection of skin and eyes.
Tiden Norsk Forlag, Postboks 8813 Youngstorget, 0028 Oslo, Norway, 19 Aug. 1994. 34p. Illus.
Johnson A.T., Dooly C.R., Brown E.Y.
Task performance with visual acuity while wearing a respirator mask
Forty-six subjects were required to perform a console-monitoring and two hand-eye coordination tasks while wearing masks with lenses clouded to give seven levels of visual acuity. The console monitoring task performance was the most sensitive to visual acuity, followed by the random hand-eye coordination task. These results can be used to help predict performance degradation when lenses become clouded by condensation or particulate deposition.
American Industrial Hygiene Association Journal, Sep. 1994, Vol.55, No.9, p.818-822. Illus. 11 ref.
Myojo T., Willeke K., Chen C.C.
Fit test for filtering facepieces: Search for a low-cost, quantitative method
A difference was found between the combined aerosol penetration through the filter medium and at a leak site at low versus high flow rate. This feature was used to differentiate face-seal leakage from filter penetration. A fit index was introduced as the most sensitive indicator of fit. When normalized by reference to the aerosol penetration through the filter material, this index displays uniform behaviour irrespective of the filter material used. The fit index is determined by relating the measured total aerosol concentration at a high flow rate to that at a low flow rate. Tests during normal breathing of a human subject compare well with the data obtained during breath-holding experiments. Available instruments may be used for this test, but need to be modified for tests on humans.
American Industrial Hygiene Association Journal, Sep. 1994, Vol.55, No.9, p.797-805. Illus. 23 ref.
Jaraiedi M., Iskander W.H., Myers W.R., Martin R. G.
The effects of respirator use on workers' productivity in a mentally stressing task
The effect of wearing half-facepiece respirators on the performance of ten subjects in a task simulating the inspection of printed circuit boards was investigated. Several experimental factors were considered, including product complexity, product quality and respirator use. Accuracy and mean reaction times were tested automatically. Speed and accuracy were generally not affected by wearing the respirator for less complex products, but a difference was found in both accuracy and time for more complex products.
American Industrial Hygiene Association Journal, May 1994, Vol.55, No.5, p.418-424. Illus. 9 ref.
Vahdat N., Swearengen P.M., Johnson J.S.
Adsorption prediction of binary mixtures on adsorbents used in respirator cartridges and air-sampling monitors
Mathematical method for predicting the performance of respirator cartridges and air sampling monitors in the presence of binary mixtures. The method used applies to a variety of binary mixture/adsorbent systems. In this study the method was applied to the adsorption of four binary mixtures of acetone and m-xylene on activated carbon, three binary mixtures of acetone and styrene on activated carbon and a binary mixture of carbon dioxide and water vapour on a molecular sieve. The predicted breakthrough curves were in agreement with experimental data.
American Industrial Hygiene Association Journal, Oct. 1994, Vol.55, No.10, p.909-917. Illus. 29 ref.
Campbell D.L., Noonan G.P., Merinar T.R., Stobbe J.A.
Estimated workplace protection factors for positive-pressure self-contained breathing apparatus
An analytical model is presented that estimates the distribution of workplace protection factor (WPF) values for positive pressure respirators. Input for the model is the instantaneous face piece pressure measured as a function of time and the distribution of WPF values for negative pressure version of the respirator. As an example application, the model was applied to 57 measurements made in a previous study. The analytical model that was developed estimates the ratio of the mass of contaminant that enters the facepiece during momentary negative pressure excursions to that which would be expected to enter a negative-pressure respirator utilizing the same facepiece. The results of the application of this analytical model are consistent with the current NIOSH assigned protection factor for a positive-pressure self-contained breathing apparatus.
American Industrial Hygiene Association Journal, Apr. 1994, Vol.55, No.4, p.322-329. Illus. 21 ref.
Zelnick S.D., McKay R.T., Lockey J.E.
Visual field loss while wearing full-face respiratory protection
The loss of visual field was quantified for 21 test subjects while they wore three different full-face respirators. Changes in visual field were quantified for each type of respirator by the use of a modified Goldmann projection perimeter. The loss of visual field was determined by comparing the area under the curve with and without a respirator. Distinct patterns of visual field loss were apparent for the different style respirators. Analysis of the patterns could lead to the design of full-face respirators with improved visual qualities, which could improve worker safety for certain occupations. The technique also could be of help in the selection of models of respiratory protection when certain visual fields must be maintained.
American Industrial Hygiene Association Journal, Apr. 1994, Vol.55, No.4, p.315-321. Illus. 19 ref.
Krishnan U., Willeke K., Juozaitis A., Myojo T., Talaska G., Shukla R.
Variation in quantitative respirator fit factors due to fluctuations in leak size during fit testing
In a controlled human study, fit factors were determined by an aerosol filter fit test and the newly developed dichotomous-flow fit test. For a higher level of respirator fit (aerosol fit factors > 1000), the aerosol fit factors were 30-60 times the corresponding flow fit factors, while for a lower level of respirator fit (fit factors < 1000) they were 2 to 4 times the flow fit factors. In a similar mannequin study considerably lower variation in fit factors was found. However, the variation in the aerosol method relative to the flow method, in the human study, is of the same magnitude as in the mannequin study. This suggests that the higher variation in the human tests is mainly due to variations in face-seal leak size and not to increased systematic errors. It was estimated that the fluctuations in face-seal leak size for the subjects with the high fit factor varied between 0.5mm and 0.7mm, and between 1.0mm and 1.3mm for the subject with the low fit factor. Thus, the fit factor determined for a human cannot be expected to be constant, even for the most perfect test system.
American Industrial Hygiene Association Journal, Apr. 1994, Vol.55, No.4, p.309-314. Illus. 13 ref.
Modeling respirator penetration values with the Beta distribution: An application to occupational tuberculosis transmission
Even workers wearing respirators may be infected following inhalation of respirable particles, termed droplet nuclei, that carry viable mycobacterium tuberculosis bacilli. Based on the expected number of infectious doses inhaled, the Poisson probability model is used traditionally to predict an individual's risk of infection. This article synthesizes the beta distribution, as applied to average penetration values among a respirator-wearing population, and the Poisson distribution, as applied to an individual's infection risk, to describe the population risk of Mycobacterium tuberculosis infection.
American Industrial Hygiene Association Journal, June 1994, Vol.55, No.6, p.515-524. Illus. 31 ref.
Krishnan U., Willeke K., Juozaitis A., Lehtimäki M., Szewczyk K.
Development of a dichotomous-flow quantitative fit test for half-mask and full-facepiece respirators
A method to quantitate the fit of elastomeric half-mask and full-facepiece air-purifying respirators was developed. The air-purifying cartridges of the respirator are attached to a reference respirator. A selected flow equivalent to the inhalation flow of the wearer is drawn through the cartridge pair. A feedback system consisting of a pressure controller and a control valve is used to set the pressure drop in the mask on the subject's face equal to the pressure drop in the reference mask. The face seal leak flow is measured while the subject holds his or her breath for a short period of time. Aerosol fit factors and flow fit factors were determined using sampling probes in three mask locations: top, centre and bottom. A Kruskal-Wallis test showed that aerosol fit factors obtained from the three locations were significantly different from each other while the corresponding flow fit factors were not.
American Industrial Hygiene Association Journal, Mar. 1994, Vol.55, No.3, p.223-229. Illus. 20 ref.
Pasanen A.L., Nikulin M., Berg S., Hintikka E.L.
Stachybotrys atra corda may produce mycotoxins in respirator filters in humid environments
This study examines the growth and toxin production of Stachybotrys atra, a cellulose-decomposing fungus, in two respirator filters with different ratios of cellulose and fibreglass at 78-100% relative humidities of air for 86 days. S. atra grew only in filter material of high cellulose content. It grew slightly at relative humidity 84-89%, but did not produce toxins. Under saturated conditions, it grew and produced satratoxin H regardless of variation in temperature.
American Industrial Hygiene Association Journal, Jan. 1994, Vol.55, No.1, p.62-65. 19 ref.
Estimating service lives of organic vapor cartridges
Procedures were developed for estimating service lives of air purifying organic vapour respirator cartridges, including methods for untested compounds and use conditions (concentration, temperature and airflow rate). Correlations of absorption capacities and adsorption-rate coefficients based on equilibrium and breakthrough curve data were reviewed. These correlations were combined using a reaction kinetic equation to estimate breakthrough times. Even limited breakthrough curve data for one vapour/carbon combination can be used to substantially improve the accuracy of the estimation. Only dry conditions (below 50% relative humidity) were considered.
American Industrial Hygiene Association Journal, Jan. 1994, Vol.55, No.1, p.11-15. Illus. 14 ref.
Wake D., Brown R.C.
Removal of radon daughter aerosols from mine air by filtration
Respirator filters and filtering facepieces were tested for penetration of radon daughter aerosols; tests were carried out in a fluorspar mine and in the laboratory. Respirators with a filtration efficiency high enough for them to be considered suitable for use against toxic dusts generally reduced radon daughter levels by 90% or more, although nuisance dust masks were ineffective. Comparison between on-site tests and tests with a standard aerosol showed that respirators that satisfy an existing standard could be expected to give reasonable protection against radon daughters.
Mining Engineer, June 1994, Vol.153, No.393, p.362-364. Illus. 9 ref.
Measurement of the sound attenuation of air-fed protective helmets
Mesure de l'affaiblissement acoustique des cagoules de protection respiratoire [in French]
Air-fed protective helmets are used to protect workers from metal dust or particle projections, particularly during sand and shot blasting operations that are also associated with high noise levels. It was therefore interesting to determine whether these devices also protect the wearers from noise. At present, however, there are no regulations governing the noise attenuation properties of this equipment, and no standardized method for measuring the sound attenuation provided. This paper presents the implementation of the MIRE (Microphone In the Real Ear) measuring technique, which seems to be suitable for measuring the sound attenuation afforded by air-fed protective helmets. Minor sound attenuation is achieved by these protective devices, indicating the need for users of these devices to wear ear protectors when exposed to sound pressure levels higher than the legal limit.
Cahiers de notes documentaires - Hygiène et sécurité du travail, 1st Quarter 1994, No.154, Note No.1953-154-94, p.61-68. 9 ref.
Héry M., Meyer J.P., Villa M., Hubert G., Wrobel R., Gerber J.M., Hecht G., Herrault J., François D.
Efficiency of unassisted half-mask dust respirators in industry
Efficacité de demi-masques anti-poussières non ventilés en situation industrielle [in French]
Thirty workers employed in 4 different factories volunteered to participate in a study of 6 unassisted half-mask dust respirators. The study investigated 3 parameters: the efficiency of filtering facepieces or unassisted half masks measured on the basis of concentrations of pollutants determined simultaneously inside and outside the respirator; the physical workload; comfort, estimated by a self-assessment questionnaire. A study of the correlations between the values of the concentrations measured inside the respirator and other parameters as well as the answers to the questionnaire, for each respirator and factory concerned, established the following: in most cases the efficiency of the respirators in industrial situations is much lower than that measured in laboratory conditions; in practical conditions of use in industry, respirator efficiency increases with dust concentration; the efficiency of the different respirators when tested in industrial conditions was practically identical, whatever the values determined in laboratory tests; comfort affects the subjective efficiency of unassisted respirators.
Cahiers de notes documentaires - Hygiène et sécurité du travail, 1st Quarter 1994, No.154, Note No.1949-154-94, p.21-33. Illus. 37 ref.
Romano F., Santoro D., Santonocito E., Suppa D.
Pneumatic machines and nut harvesting: Identifying systems restricting the emission of dust during harvesting
Macchine pneumatiche e raccolta di nocciole: Individuazione di sistemi atti a limitare l'emissione di polveri durante la raccolta [in Italian]
To meet the environmental hygiene problems of large amount of dust produced during the process of picking hazelnuts in Italy by means of turbo-aspirating machines, this research identifies suitable filtering systems. The main types of dust removers for medium-fine dusts were studied: a comparative examination showed that mechanical dust removal by cyclone (centrifugal dust separator) was the most effective. Two prototype filters were designed and built, each consisting of four cyclones with a diameter of 350mm and 250mm, respectively. Field tests showed that the 350mm cyclone had a dust removing capacity of 90%, with no reduction in performance caused by the dust going through it, while the 250mm cyclone removed 93.75% with a reduction in performance of approximately 30%. Though both filtering systems appear to be acceptable, the latter one allows a further reduction of 50% of the fine dust in the working environment. Summary in Italian, French, German, English and Spanish.
Prevenzione oggi, Apr.-June 1993, Vol.V, No.2, p.143-161. Illus.
Tanaka S., Kido S., Yanagawa M., Seki Y., Imamiya S.
Fitting of the interstice between the full facepiece of respirators and the face of plant quarantine fumigators - Report 1
Shokubutsu ken eki kunjō sagyōsha no ganmen to zenmen mentai to no mitchaku sei ni kansuru kenkyū - Dai ippō [in Japanese]
A mask fitting tester was used for measuring the leakage rate of air through the interstice between the facepiece of selected full-facepiece respirators and the faces of plant quarantine fumigators. When a flat probe inserted at the edge of the mask was used to collect the inlet air inside the mask, leakage occurred around the place where the probe had been inserted. Therefore, an attachment to the exhalation valve was developed. The measurement made use of airborne dust particles in the room air, while the fumigators were exposed to gaseous substances, so a comparison was made between the use of dust particles and of gaseous substances as test material. The same leakage rate was obtained for both of them.
Journal of Science of Labour - Rōdō Kagaku, 10 Feb. 1993, Vol.69, No.2, p.57-62. Illus. 9 ref.
Lee B.K., Lee C.W., Ahn K.D.
The effect of respiratory protection with biological monitoring on the health management of lead workers in a storage battery industry
Zinc protoporphyrin in blood samples from 85 lead-exposed workers in a storage battery manufacturing plant in Korea was determined monthly for one year. The workers participating in the study wore maintenance-free respirators. The levels of lead and haemoglobin in blood and of delta-aminolevulinic acid in urine were determined at the beginning and the end of the study. A questionnaire was administered to collect information on symptoms related to lead exposure. The use of respirators significantly decreased the blood lead and zinc protoporphyrin levels and the levels of delta-aminolevulinic acid in urine but not the mean haemoglobin concentrations. The prevalence of lead related symptoms decreased more significantly in female workers than male workers.
International Archives of Occupational and Environmental Health, 1993, Vol.65, Suppl.1, p.S181-S184. Illus. 13 ref.
Jouannique V., Hure P., Falcy M.
Respiratory protective equipment. Medical criteria determining their potential use
Les appareils de protection respiratoire - Eléments médicaux de détermination d'aptitude à leur utilisation [in French]
Respiratory protection is necessary when air pollutants (dusts, gases or vapours) are present, when oxygen is scarce and when pollution control measures are inadequate. It falls upon the practitioner to determine whether workers needing protection are able to wear such respiratory equipment. An overview of the devices available is followed by a review of the physiological effects associated with their use and of the disorders or diseases which may make it impossible for workers to use them. Additional examinations which may be prescribed in order to assess the ability to wear such equipment are envisaged. In conclusion, an approach is proposed to assess the ability to wear respiratory protection taking into account three types of situations.
Documents pour le médecin du travail, 4th Quarter 1993, No.56, p.321-331. Illus. 33 ref.
Zellers E.T., Sulewski R.
Modeling the temperature dependence of N-methylpyrrolidone permeation through butyl- and natural-rubber gloves
Study of breakthrough time of N-methylpyrrolidone for butyl and natural rubber gloves. The gloves were tested at four temperatures from 25-50°C. The butyl rubber glove did not show any breakthrough after four hours. The natural rubber gloves showed permeation rates applying well with the Arrhenius relationship. Extrapolation of the temperature to 70-93°C gave breakthrough values of less than 0.5-2 minutes. Experimental values were compared with permeation models. The Fickian diffusion equation gave values of breakthrough time and steady-state permeation time within 23 and 50% respectively of the experimental values.
American Industrial Hygiene Association Journal, Sep. 1993, Vol.54, No.9, p.465-479. Illus. 52 ref.
Johnson A.T., Grove C.M.
Respirator mask design modules and their interactions
Mask design modules and how they relate to mask physiological effects are presented in a respirator performance rating table scheme. The main factors are: vision, communication, respiration, thermal comfort and physiological effects of elevated temperatures, personal support (e.g., lens design affects the ability of mask wearers to communicate visually), physical and psychological aspects.
American Industrial Hygiene Association Journal, Dec. 1993, Vol.54, No.12, p.749-751. 2 ref.
Hinds W.C., Bellin P.
The effect of respirator dead space and lung retention on exposure estimates
Equations that predict the magnitude of the effect of lung retention and respirator dead space on average inhalation concentration and other related quantities were developed, tested and applied. The equations were validated by numerical simulation and experimental measurement with a respirator on a mannequin connected to a breathing machine. Experimental data verifying the applicability of the equations are presented, as are applications of the equations and procedures to various types of respirator performance measurements and to a predictive respirator performance model. Graphs give correction factors, which in all cases were less than 2. Under typical conditions of workplace protection factor measurement with half-mask respirators, average inhalation concentration will be 105% to 125% of full-cycle average concentration.
American Industrial Hygiene Association Journal, Dec. 1993, Vol.54, No.12, p.711-722. Illus. 22 ref.
Fox S.H., DuBois A.B.
The effect of evaporative cooling of respiratory protective devices on skin temperature, thermal sensation, and comfort
Theoretical considerations of thermal exchange between the face and the environment with and without a mask are discussed to elucidate factors that may improve the design of masks to increase their acceptability. Evaporative cooling of a dummy mask and a modified Scott respirator was tested in resting and exercising subjects. Skin temperature was significantly reduced when wet felt covered the outer surface of both masks. At rest the masks were rated by subjects as significantly more comfortable than dry felt on the outer surface.
American Industrial Hygiene Association Journal, Dec. 1993, Vol.54, No.12, p.705-710. Illus. 10 ref.
Determining the service lives of organic-vapor respirator cartridges for nitroglycerin under workplace conditions
A field study, with the aim of estimating the service lives of different brands of organic-vapour respirator cartridges, is presented. The measurement were carried out in a gunpowder factory. The breakthrough time for nitroglycerin was between seven and 81 hours (depending on the brand of the tube) when the concentration in the air was 1mg/m3. No premature breakthrough was detected.
American Industrial Hygiene Association Journal, Aug. 1993, Vol.54, No.8, p.432-439. Illus. 28 ref.
Brown R.C., Vaughan N.P.
Measurement of the leakage and fit factor of a filtering facepiece by continuous monitoring of pressure pulsations
The fit factor of filtering respirators is measured by continuous monitoring of the pressure produced in the respirator cavity by injecting and withdrawing a volume of air so that the volume varies sinusoidally with time. Comparison between measurements made when leaks occur and the measurements made without leakage enables a fit factor to be calculated for each breath. Results obtained by the use of this method on a filtering respirators worn by a manikin agree with bubble flowmeter measurements, although systematic differences exist. The method is most accurate when leakage is large, and is potentially useful for fit factors up to about 50, and leakages down to about 2%.
American Industrial Hygiene Association Journal, Aug. 1993, Vol.54, No.8, p.409-416. Illus. 10 ref.
Wallis G., Menke R., Chelton C.
Workplace field testing of a disposable negative pressure half-mask dust respirator (3M 8710)
The performance of the 3M 8710 dust/mist halfmask respirator was characterized in a workplace (alkaline battery plant) atmosphere that contained concentrations of manganese dioxide dust in the range 0.14 to 20 mg/m3 as manganese. Workplace protection factors (WPFs) were calculated from the ratio of the concentration outside the respirator (C(o)) and that measured simultaneously inside the respirator (C(i)). The WPFs were in the range of 2.8 to 248. The relation of WPF to C(o) for 13 was approximately linear. The size distribution of manganese dioxide particles was determined at different values of C(o). The relation of C(p), the concentration of particles in stated particle size groups, and C(o) was linear as well. An explanation for the dependence of WPF on C(o) could be that the performance of the respirator is related to particle size.
American Industrial Hygiene Association Journal, Oct. 1993, Vol.54, No.10, p.576-583. Illus. 17 ref.
Ny E.T., Heederik D., Kromhout H., Jongeneelen F.
The relationship between polycyclic aromatic hydrocarbons in air and in urine of workers in a Söderberg potroom
The relationship between increase of urinary 1-hydroxypyrene over the workweek and the airborne concentrations of benzo(a)pyrene and coal tar pitch volatiles (CTPVs) were studied among groups of workers in a vertical-stud Söderberg potroom of an aluminium smelter. There was a strong correlation between the natural logarithm of the pyrene concentration and the natural logarithm of the total polycyclic aromatic hydrocarbon (PAHs) concentration in personal air samples. A strong positive correlation was also found between the natural logarithm of increase in urinary 1-hydroxypyrene and the natural logarithm of the estimated airborne PAH exposure when the use of extra layers of cloth under respirators was taken into account. A contradictory fact was found: the use of extra facial protection seemed to lead to a strong increase of 1-hydroxypyrene over the workweek.
American Industrial Hygiene Association Journal, June 1993, Vol.54, No.6, p.277-284. Illus. 27 ref.
The development and use of dust respirators in Japan (Report 1) - Research and standards before 1970
Waga kuni ni okeru bōjin masuku (dai-ichi ho) - 1970-nen goro made no kenkyū to kikaku [in Japanese]
The incidence of occupational lung diseases due to exposure to mine dust was first recorded around 1800, but the use of anti-dust measures started only at the beginning of this century. The first national standards for dust respirators were brought into practice in 1950, both in the Japanese Industrial Standards (JIS) and in the regulatory measures by the Ministry of Labour. The governmental certification system according to these standards was also initiated. The new system gave rise to a series of studies on filtering materials, the physiological effects of the use of dust respirators and their actual utilization at workplaces. Thus research and technology developed rapidly, in particular concerning filters, respiratory resistance, respiration valves, hindrances in the field of vision and measures to promote the use of respirators. As a result, the efficiency of dust respirators improved markedly in the 1950s and 1960s, with the help of newly developed materials and advanced production technologies. This led to the revisions of the dust respirator standards in 1955 and 1962. The regulations were also revised from time to time so as to adjust them to workplace conditions. These developments provided an important basis for enacting more developed standards that were to follow in accordance with the Industrial Safety and Health Law in the early 1970s.
Journal of Science of Labour - Rōdō Kagaku, 10 Oct. 1993, Vol.69, No.10, p.443-460. Illus. 39 ref.
Tanaka S., Kido S., Seki Y., Imamiya S.
Service lives of respirator cartridges for 46 organic solvent vapours
Yūki yōzai jōki 46 shurui ni taisuru yūki gasu-yō kyūshūkan no haka jikan [in Japanese]
Breakthrough times were determined for 46 organic solvent vapours with a G-31 cartridge, which meets Japanese standards. A linear relation was established between the breakthrough times of the solvents and their boiling points: T(min) = 1.1D(°C)+36.7; correlation coefficient 0.77.
Japanese Journal of Industrial Health - Sangyō-Igaku, July 1993, Vol.35, No.4, p.290-291. Illus. 4 ref.
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