Respiratory protection - 688 entries found
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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.
Zejda J.E., Hurst T.S., Barber E.M., Rhodes C., Dosman J.A.
Respiratory health status in swine producers using respiratory protective devices
A cross-sectional survey on respiratory health in swine producers showed that 30% of 301 men examined usually used a dust mask when working inside a barn. They did not differ significantly from non-users of dust masks in respect of respiratory symptoms and lung function. This analysis was undertaken to determine whether the respiratory health of dust mask users was associated with reasons for their having started to use individual respiratory protection. The subjects were recontacted in order to identify those who started using a mask deliberately to prevent symptoms (42 men) and those who started using protection because of pre-existing respiratory symptoms (44 men). Not unexpectedly, between-group comparisons of respiratory symptoms and lung function suggest that swine producers who wear dust masks for preventive purposes have better respiratory health than those who wear dust masks because of symptoms or those who do not use individual respiratory protection. Further studies are needed to evaluate the full impact of respiratory protection in these workers.
American Journal of Industrial Medicine, May 1993, Vol.23, No.5, p.743-750. 14 ref.
Hudnall J.B., Suruda A., Campbell D.L.
Deaths involving air-line respirators connected to inert gas sources
During 1984 to 1988, the US Occupational Safety and Health Administration (OSHA) investigated 10 incidents, with 11 fatalities, involving the inadvertent connection of air-line respirators to inert gas supplies. Seven deaths resulted from connecting an air-line respirator supply hose to a line which normally carried inert gas. Four deaths were caused by leakage or backfill of inert gas into a line which normally carried breathable air. Ten of the deaths were from nitrogen and one from argon. The circumstances of the 11 deaths indicated that coupling compatibility and supervisory oversight were major factors in the inappropriate supply of irrespirable gas to the respirators worn by these workers. Awareness among safety personnel of the hazards of asphyxiation by inert gas, and compliance with current OSHA regulations, the ANSI Z88.2 standard, and National Institute for Occupational Safety and Health (NIOSH) respirator certification approval regulations would have prevented these fatalities.
American Industrial Hygiene Association Journal, Jan. 1993, Vol.54, No.1, p.32-35. 13 ref.
Grin and wear it
Brochure explaining the reasons for wearing respiratory protective equipment in certain jobs. It also provides broad guidance on the choice of the right equipment, and on how to wear it.
HSE Information Centre, Broad Lane, Sheffield S3 7HQ, United Kingdom, 1993. 4p. Illus. 1 ref.
Böning A., Gmehling J.
Bundesanstalt für Arbeitsschutz
Permeability of protective gloves to solvents
Durchlässigkeit von Schutzhandschuhen gegenüber Lösemitteln [in German]
The permeability of ten different kinds of protective gloves to five commonly used organic solvents and to solvent mixtures was studied. In permeation test cells of various design the time to breakthrough and the permeation rate were determined. The influence of material thickness, test cell design and temperature on the results was studied. Only one of the ten gloves, which was made of polyethylene, polyvinyl alcohol and laminated polyethylene, was resistant to solvent penetration. A standard procedure for testing the permeability of protective gloves to organic solvents was derived from the results of the experiments.
Wirtschaftsverlag NW, Verlag für neue Wissenschaft GmbH., Postfach 10 11 10, Am Alten Hafen 113-115, 2850 Bremerhaven 1, Germany, 1992. 66p. Illus. 174 ref. Price: DEM 35.00.
Increasing acceptance of respirators by positive supply filter systems
Erhöhung der Trageakzeptanz von Atemschutzgeräten durch gebläseunterstützte Systeme [in German]
Air purifying respirators are perceived as a burden at work if they weigh more than 10kg, the breathing resistance is higher than 30mbar, temperature and humidity of the inhaled air are high and the CO2 concentration amounts to more than 2%. Positive supply filter respirators avoid these disadvantages as was confirmed by comparative 1h-tests. While walking on a treadmill with a speed of 5.3km/h, five male and two female volunteers assessed the comfort of an air purifying respirator with the particulate filter attached to the hose mask and a positive supply filter respirator with the filter and air supply unit attached to the belt.
Sicher ist Sicher, June 1992, Vol.43, No.6, p.290-294. Illus. 8 ref.
Chen C.C., Willeke K.
Characteristics of face seal leakage in filtering facepieces
Several studies have found that aerosol size, testing method, leak size, leak position, sampling probe location, and the mixing condition inside the respirator affect the results of fit factor measurements. This study focuses on the effect of leak shape and filter resistance. Four leaks of different shape but the same cross-sectional area were used to study their effect on aerosol penetration. Particle size-dependent aerosol concentrations were measured inside and outside the respirators. The filtering facepieces were sealed to a mannequin and artificial leaks were inserted near the right cheek. Aerosol penetration was measured for five flow rates ranging from 5 to 100L/min. At a given pressure differential, a slit-like leak and multiple circular leaks passed less aerosols than a single circular leak of equal cross-sectional area because the leak flow decreases with an increase in leak shape complexity. If there is substantial lack of face seal fit and the breathing rate is low, a HEPA (high-efficiency particulate air) respirator may provide less protection than a dust-mist respirator because the pressure drop is considerably higher for a HEPA respirator, resulting in more aerosol flow through the leak.
American Industrial Hygiene Association Journal, Sep. 1992, Vol.53, No.9, p.533-539. Illus. 25 ref.
Feigley C.E., Chen H.C.
Penetration of several filter materials by asbestos as a function of fiber dimensions
The purpose of this research was to determine the penetration of several filter materials commonly used in building air-handling systems by asbestos fibres. An airstream containing tremolite asbestos fibres was passed through these materials and the upstream and downstream fibre concentrations were measured by membrane filtration and scanning electron microscopy. The penetration of these materials was determined as a function of asbestos fibre diameter and length at two typical air velocities. For glass fibre filter materials, the maximum penetrations were 3.5% and 0.1% compared with American Society for Testing and Materials dust spot efficiency ratings of 80% and 90%, respectively. Thus, the glass fibre filters appear to be capable of greatly reducing the concentration of asbestos fibres in a building air-handling systems. Roll and panel filter materials consisting of polyester fibres exhibited penetrations from 15% to nearly 90%. Thus, roll and panel filters tested are not recommended for this purpose.
American Industrial Hygiene Association Journal, Dec. 1992, Vol.53, No.12, p.767-772. Illus. 19 ref.
Hewson G.S., Ralph M.I.
Determination of program protection factors for half-mask respirators used at a mineral sands separation plant
The performance of half-mask filter cartridge respirators was evaluated at a mineral sands separation plant. Inhalation exposure was estimated by measuring the dust and radioactivity concentration inside the respirator while it was worn or hanging around the worker's neck. The programme protection factor was determined by simultaneously measuring inside-mask and ambient (outside-mask) concentrations. A total of 27 tests were conducted, covering three brands of half-mask respirators. Programme protection factors varied from 1.8 to 13 for dust exposure and 2.5 to 21 for radioactivity exposure. The geometric mean programme protection factor over all the tests was 5.1 (geometric standard deviation [GSD]=1.7) for dust exposure and 7.5 (GSD=1.7) for radioactivity exposure. A minimum programme protection factor of 3.5 could be applied to ambient airborne concentration data to obtain a conservative, but more realistic, estimate of inhalation exposure on a worker category basis.
American Industrial Hygiene Association Journal, Nov. 1992. Vol.53, No.11, p.713-720. Illus. 20 ref.
Respiratory protection program and record keeping kit
Part 1 of this workbook describes a minimally-acceptable respirator programme meeting the requirements of ANSI Z88.2-1980 (Practices for Respiratory Protection) and covers: preparation of written standard operating procedures; programme administration; medical evaluation and surveillance; hazard evaluation and respirator selection; respirator fitting and training; facial hair, contact lenses and eye and face protective devices; respirator inspection and maintenance; supervision of respirator use; respirator programme evaluation. An annotated list of reference material and standards is included. Part 2 contains a sample written standard operating procedure including sample forms and records.
Van Nostrand Reinhold, 115 Fifth Avenue, New York, NY 10003, USA, 1992. 73p. Illus. 9 ref. Also available from: International Thomson Publishing Services Ltd., Cheriton House, North Way, Andover SP10 5BE, Hampshire, United Kingdom. Price: GBP 52.00.
Nicas M., Spear R.C.
A probability model for assessing exposure among respirator wearers - Part I. Description of the model
The basic respirator equation states that the contaminant level inside a respirator (Cl) is the product of the contaminant level outside the respirator (Co) and the decimal fraction penetration (P). A probability model based on this relation accounts for between-wearer and within-wearer variability in both Co levels and P values. The assumptions underlying the model are consistent with current knowledge about the variability in Co levels and P values. The model provides the basis for assessing the probability of over-exposure to acute toxicants and to chronic toxicants among a respirator-wearing population.
American Industrial Hygiene Association Journal, July 1992, Vol.53, No.7, p.411-418. Illus. 22 ref.
Chen C.C., Lehtimäki M., Willeke K.
Aerosol penetration through filtering facepieces and respirator cartridges
Air-purifying respirators are certified following the National Institute for Occupational Safety and Health (NIOSH) filter test criteria, which specify a range for the mean particle size and the measure of spread permissible for the test aerosol. Filtering facepieces (disposable respirators) and cartridges of the dust-mist, dust-mist-fume, and high-efficiency particulate air type were tested. Under the same test conditions, the "quality factor" (aerosol penetration and pressure drop) of one respirator may be up to 6.6 times greater than that of another of the same type. The filter quality factor has a greater aerosol size dependency as airflow and aerosol size increase. In general, cartridges have a larger surface area than filtering facepieces but not necessarily lower filter penetration or higher filter quality. Data analysis shows that the best dust-mist respirator tested may provide five times more protection than the worst dust-mist respirator.
American Industrial Hygiene Association Journal, Sep. 1992, Vol.53, No.9, p.566-574. Illus. 25 ref.
Johnson A.T., Grove C.M., Weiss R.A.
Respirator performance rating tables for nontemperate environments
Respirator performance rating tables have been constructed for hot, humid (29°C, 95% RH); hot, dry (49°C, 30% RH); and cold, dry (-32°C, 70% RH) conditions. These tables convey expected wearer performance percentages compared to unmasked workers for various mask elements and work rates. The hot, humid condition was found to be the most severe overall. Many table entries approach 100%, thus leading to difficulties in correcting mask deficiencies.
American Industrial Hygiene Association Journal, Sep. 1992, Vol.53, No.9, p.548-555. Illus. 9 ref.
Yoon Y.H., Nelson J.H., Lara J., Kamel C., Fregeau D.
A theoretical model for respirator cartridge service life for binary systems - Application to acetone/styrene mixtures
A theoretical model, previously developed to assess respirator cartridge service life, was applied to various acetone/styrene two-component (binary) assault systems. Experimental data were interpreted in terms of the model. The specific influence of the compound assault concentrations on respirator cartridge service life was studied, as breakthrough curves were generated for both acetone and styrene for each of several different binary systems. An interesting phenomenon observed for the acetone/styrene systems was the displacement (from the carbon) of previously adsorbed acetone molecules by styrene molecules. The study showed that the service life of cartridges exposed to acetone/styrene mixtures depends on the assault concentration of each compound and is significantly shortened by the displacement phenomenon.
American Industrial Hygiene Association Journal, Aug. 1992, Vol.53, No.8, p.493-502. Illus. 19 ref.
A guide to respirators and breathing apparatus
General guide suitable for the training of workers in the proper use of respirators and breathing apparatus. Contents: general principles of respiratory protection; classification of inhalation hazards (particulate, gaseous, and vapour contaminants; lack of oxygen and main types of respirators; air purifying respirators; airline respirators; self-contained breathing apparatus; respiratory protection programmes; practical considerations (training and instruction; face fitting; supervision in dangerous atmospheres; location); respirator maintenance and storage. In appendix: requirements for air quality (compressors or cylinders) for supplied air respirators.
Occupational Safety and Health Service, Department of Labour, P.O. Box 3705, Wellington, New Zealand, 1992. 51p. Illus.
Brueck S., Lehtimaki M., Krishnan U., Willeke K.
Method development for measuring respirator exhalation valve leakage
A quality assurance test was developed for respirators to be administered before field use. The purpose of the test is to control for leakage through the exhalation valve or any other potential leak source such as the seal between the respirator body and the air purifying cartridges. Respirator leaks are most likely caused by the exhalation valve. Exhalation valve leakage was measured in both new valves and field-use valves. Leakage through new valves was minimal in most cases, but one brand of new valves was found to leak significantly. Five percent of 67 field-used exhalation valves had unsatisfactory leakages indicating that dust or debris on the exhalation valve or valve seat may compromise the proper functioning of the valves. The cleaning of both new and field-used exhalation valves with water caused leakage to decrease significantly, thus supporting the importance of good respirator cleaning programmes for industry.
Applied Occupational and Environmental Hygiene, Mar. 1992, Vol.7, No.3, p.174-179. Illus. 14 ref.
Hori H., Tanaka I.
Adsorption characteristics of organic solvent vapor on activated carbon under fluctuating vapor concentrations
Air containing organic solvent vapour was introduced into a glass column packed with activated carbon particles under conditions of rectangularly fluctuating vapour concentration. Adsorption and non-adsorption cycles were repeated at the same intervals under a constant flow rate. The experimental breakthrough curves and the breakthrough times were compared with those obtained under a constant vapour concentration. The breakthrough curves at the fluctuating vapour concentration were oscillated and the breakthrough times were sometimes significantly shorter than those at constant vapour concentration when the designed average vapour concentration (concentration averaged over an equal number of on and off cycles) was equal. Because vapour concentrations in the work environments fluctuate, the effective time of charcoal tubes and respirator cartridges may become shorter than the expected times based on laboratory studies performed under conditions of constant vapour concentration.
American Industrial Hygiene Association Journal, June 1992, Vol.53, No.6, p.347-351. Illus. 14 ref.
Vandenplas O., Malo J.L., Cartier A., Perreault G., Cloutier Y.
Closed-circuit methodology for inhalation challenge tests with isocyanates
A closed-circuit apparatus for generating isocyanates in a gaseous form was developed to help in the diagnosis of isocyanate-induced occupational asthma. Twenty subjects suspected of having isocyanate-induced asthma were tested using both the older, small challenge room method and the newer method in a randomised sequential way. Isocyanate concentrations were more stable with the closed-circuit apparatus than with the challenge room method. The percentage of the total exposure time during which concentrations were above 20ppb was reduced from 11.3 to 4.5%. The two methods yielded the same number of positive and negative responses, except for one subject who did not have a positive reaction when tested with the challenge room method. The pattern and magnitude of asthmatic reactions were similar for both methods. However, the duration of exposure was shorter with the challenge room method than with the closed-circuit method.
American Review of Respiratory Disease, Mar. 1992, Vol.145, No.3, p.582-587. Illus. 30 ref.
Hattori Y., Kodama Y., Kawamoto T.
Questionnaire survey for the fitness of protective equipments used by workers
Rōdō eisei hogogu no mondaiten - Rōdōsha ni taisuru ankēto chōsa [in Japanese]
Questionnaire surveys on the opinions of workers regarding personal protective equipment were conducted for three consecutive years (1987-1989) at a personal protective equipment exhibition which is held annually at an industrial enterprise during Japan's Labour Hygiene Week, and is attended by workers of the enterprise and associated enterprises. One out of five to six returned questionnaires indicated problems associated with protective equipment at work, but the number and rate of such complaints declined from year to year. Safety spectacles were by far the most common source of complaint (10% of total questionnaire returned), followed by earplugs (1.3%) and dust masks (1.2%), but the number and rate of complaints on protective spectacles decreased each year; the most frequent complaints were: "lens becoming misty", "cords becoming weakened", and "lens easily scratched".
Japanese Journal of Industrial Health - Sangyō-Igaku, Jan. 1992, Vol.34, No.1, p.40-41. 3 ref.
Health and Safety Executive
Respiratory protective equipment. Legislative requirements and lists of HSE approved standards and type approved equipment
This guidance document is a revision of the 1991 edition (see CIS 91-1976). Contents: legislative requirements for the use of RPE in the United Kingdom, type approval certificates and user action; list of HSE-approved standards for RPE; annotated list of HSE-approved equipment; addresses of manufacturers and suppliers.
HMSO Books, PO Box 276, London SW8 5DT, United Kingdom, 3rd ed., 1992. 63p. Price: GBP 3.25.
NIOSH certified equipment list as of December 31, 1991
This list is provided as part of the NIOSH testing, approval and certification programme for personal protective devices and industrial hazard measuring instruments (previous list: see CIS 91-1958). Certified products listed include coal mine dust personal sampler units, self-contained breathing apparatus, gas masks, supplied air respirators, particulate respirators, chemical cartridges, powered air purifiers and vinyl chloride respirators. Brief technical details are given of each product listed, and names and addresses of manufacturers and distributors are provided.
Publications Dissemination, DSDTT, National Institute for Occupational Safety and Health (NIOSH), 4676 Columbia Parkway, Cincinnati, OH 45226, USA, Jan. 1992. 549p.
Particulate filter against Diesel soot
Partikelfilter contra Dieselruss [in German]
A filter for the removal of soot from the exhausts of industrial trucks, such as fork-lift trucks, is described. It is composed of three ceramic filter-sets housed in a steel casing. For additional conversion of carbon monoxide and hydrocarbons in the exhaust a precious metal catalyst-coated version is available. The filter is regenerated usually after 8 hours by burning the collected soot. It is connected to the 220V mains for this purpose.
Unfall-Stop - Mitteilungsblatt der Grosshandels- und Lagerei-Berufsgenossenschaft, Sep. 1991, No.5, p.4-6. Illus.
Mellström G.A., Landersjö L., Boman A.S.
Permeation testing of protective gloves by using two different permeation cells in an open-loop system (neoprene-toluene)
Two permeation test cells of different sizes were used in a study of the permeation of toluene through two neoprene gloves and special neoprene sheet stock. Three flow rates of the collecting medium through the test cells were used to explore to what extent variation in flow rate would affect the breakthrough times and the steady-state permeation rate. The breakthrough time values were not affected to a significant degree by cell size or by increasing the flow rate of the collecting medium from 60 to 120mL/min. The steady-state permeation rate values were evidently influenced by the flow rate of the collecting medium and by the size and configuration of the test cell.
American Industrial Hygiene Association Journal, Aug. 1991, Vol.52, No.8, p.309-314. Illus. 14 ref.
Cohen H.J., Levine S.P., Garrison R.P.
Development of a field method for determining the service lives of respirator cartridges - Part IV. Results of field validation trials
Results of a fourth study on the use of small, carbon-filled glass tubes (respirator carbon tubes - RCTs), for predicting the service lives of organic vapour respirator cartridges are presented. Organic vapours are drawn through the RCT by using a personal sampling pump until breakthrough is detected. This breakthrough time is then used in conjunction with a bed-resident adsorption model to predict the breakthrough time of a cartridge containing carbon identical to that in the RCT. In a workplace environment the RCT method was applied to the prediction of breakthrough times of known concentrations of carbon tetrachloride and pyridine. The method predicted cartridge breakthrough times to an accuracy of ±8% at the 95% confidence level, which equalled or exceeded results of previously reported laboratory studies. Actual breakthrough times averaged within ±5% of those predicted with previous laboratory data. A plot of bed-residence time versus breakthrough time yielded a coefficient of determination of 0.71 when ambient concentrations were standardised.
American Industrial Hygiene Association Journal, July 1991, Vol.52, No.7, p.263-270. Illus. 24 ref.
Crutchfield C.D., Murphy R.W., Van Ert M.D.
A comparison of controlled negative pressure and aerosol quantitative respirator fit test systems by using fixed leaks
An automated version of a new method for quantitative respirator fit testing by controlled negative pressure was compared with a computerised aerosol fit test system. The controlled negative pressure technique eliminates many of the problems associated with aerosol and pressure decay fit test methods. A series of fixed leaks was used to compare the leak measurement capabilities of the controlled negative pressure system against a standard computerised aerosol fit test system. Negative pressure and aerosol fit factors determined for a series of fixed leaks through hypodermic needles were highly correlated with each other (r=0.998) and with the cross-sectional areas of the leak needles (r>0.995).
American Industrial Hygiene Association Journal, June 1991, Vol.52, No.6, p.249-251. Illus. 3 ref.
Kongerud J., Rambjør Ø.
The influence of the helmet respirator on peak flow rate in aluminum potroom
The efficiency of the Racal Airstream helmet respirator in improving peak expiratory flow rates (PEFR) and symptoms (dyspnoea, wheezing, and cough) in aluminum potroom workers with respiratory complaints was assessed in 19 workers. Peak expiratory flow readings and symptom recording from a two-week working period with use of the respirator were compared with a period when the 3M 9906 disposable mask was used. The study was designed as a randomised, parallel, cross-over study with five or six daily measurements of PEFR and daily symptom recording. A significant number of workers (15) had a higher mean peak flow in the helmet period than in the non-helmet period (p<0.01); symptoms did not improve significantly in the helmet period. Objective evidence of respiratory protection was observed for the group of workers as a whole, but the effect on symptoms as well as individual effect on peak flow was minor in the majority of the workers.
American Industrial Hygiene Association Journal, June 1991, Vol.52, No.6, p.243-248. Illus. 20 ref.
The physiological cost of wearing a disposable respirator
A series of experiments was carried out to measure the effects of wearing a single-use disposable respirator. Cardiopulmonary effects, breathing resistance, and heat stress were measured. Ten male volunteers exercised on a treadmill both with and without 3M Model 8715 respirators. Workloads corresponding to light, moderate, and heavy levels were calculated for each volunteer based on his maximal oxygen uptake. As work intensity increased, an increase in breathing resistance was found. The respirator use trial had a significantly increased respiratory rate. Heart rate also showed a dose-related increase as work intensity increased and was significantly greater in the respirator trials at heavy work levels and during recovery. Systolic blood pressure showed a biphasic response to respirator use, being significantly lower at rest and higher at high work levels. Air temperatures anterior to the face were on average 7.5°C higher in the respirator trials. The use of a respirator is associated with significant physiological costs, especially at moderate and heavy work loads.
American Industrial Hygiene Association Journal, June 1991, Vol.52, No.6, p.219-225. Illus. 48 ref.
Colton C.E., Birkner L.R., Brosseau M.M.
Respiratory protection - A manual and guideline
This intention of this revised manual (see CIS 81-509 for original edition) is to provide plant personnel responsible for respiratory protection with enough information to establish a programme in conformity with respiratory protection standards. Contents: programme administration and record keeping; programme surveillance and evaluation; medical evaluation; work area surveillance and industrial hygiene; introduction to selection and use; particulate filter respirators; chemical cartridge respirators and gas masks; air-line respirators; self-contained breathing apparatus; powered air-purifying respirators; supplied-air suits; emergency escape respirators; fire fighting; special respirator use problems; training; respirator fitting; self-contained breathing apparatus training; inspection, cleaning and maintenance.
American Industrial Hygiene Association, Akron, Ohio, USA, 1991. 130p. Illus. Bibl.ref.
Arechiga H., Greco A.
The hidden hazard - Respiratory protection: Welding fumes
"El riesgo oculto" - Protección respiratoria: humos de soldadura [in Spanish]
Various welding types are examined (arc, oxyacetylene and resistance welding). Attention is paid to the production of welding fumes as an occupational risk. Health hazards of welding fumes are reviewed and presented in tables. These include: pulmonary fibrosis and oedema, bronchitis, metal-fume fever, eye and respiratory tract irritation. Ventilation and respirators are presented as protective measures. Importance is given to training on the use and maintenance of respirators.
Protección y seguridad, Sep.-Oct. 1991, No.5, p.10-14. Illus.
Testing methods for air filters - Present and future European standards
Prüfverfahren für Luftfilter - Derzeitige und zukünftige europäische Normen [in German]
The methods of determining the collection efficiency of filters in air-conditioning systems described in German Standards DIN 24185 and DIN 24184 are outlined. These standards comply with international standards. They concern filters used for the removal of dust and aerosols from the air and those used for the removal of suspended particulate matter, viruses and other microorganisms from the air of clean rooms. The testing method in DIN 24184 for clean-room filters is based on photometry. It cannot evaluate collection efficiencies > 99.999%. A new testing method is outlined capable of evaluating filters with collection efficiencies up to 99.99999%. It is based on determining the diameter of the most penetrating particles.
HLH - Zeitschrift für Heizung, Lüftung, Klimatechnik, Haustechnik, Aug. 1991, Vol.42, No.8, p.459-462. Illus.
Brown R.C., Wake D.
Air filtration by interception - theory and experiment
A model of aerosol particle capture in filters, by interception, is developed, using a more general approach than simple single-fibre theory. A simple relationship exists between aerosol penetration and particle size, fibre size and the quotient of pressure drop and filtration velocity. Agreement between theory and experiment is good, both for the functional dependence of penetration on aerosol size and for the absolute values of penetration.
Journal of Aerosol Science, 1991, vol.22, n°2, p.181-186. Illus. 12 ref.
Oestenstad R.K., Zwissler A.M.
Comparison of fit provided by natural and silicone rubber facepieces of the same brand of half-mask respirator
The fit provided by natural and silicone rubber facepieces of the same brand and size of half-mask respirator were compared by performing multiple fit tests on 45 subjects. The tests consisted of a six-exercise protocol while measuring the penetration of ambient room aerosols. The fit factors for the silicone rubber facepiece were found to be significantly greater than those for the natural rubber facepiece. It was noted that the maximum and minimum fit factors obtained with the natural rubber facepiece were higher than those for the silicone rubber facepiece. The variability of fit factors for the silicone rubber facepiece was also found to be higher than that of the natural rubber facepiece. This would affect the calculation of fit factor lower tolerance limits and should be considered in estimating the lowest likely fit provided by a respirator for an individual or a group of wearers.
Applied Occupational and Environmental Hygiene, Sep. 1991, Vol.6, No.9, p.785-789. Illus. 19 ref.
A study on facepiece-to-face fitting of dust respirators (Report 3) - On the mask fitting tester
Bōjin masuku no ganmen e no mitchakusei ni kansuru kenkyū - dai-3-hō - mask fitting tester ni tsuite [in Japanese]
There are on the market in Japan 2 types of dust respirators complying with Ministry of Labour standards: replaceable-cartridge dust respirators and disposable dust respirators. According to the provisions of the standards, a replaceable-cartridge dust respirator is required to provide a device which enables the wearer to check the facepiece-to-face fitting easily at any time, but a disposable dust respirator is not required to have such a check system. A Mask Fitting Tester was developed and the results of tests using it are reported. The Tester includes a particle counter that can count the number of particles with a diameter greater than 0.7µm. The Tester quantitatively and easily tests mask fit. The measurement can be done without modifying the dust respirator and takes about 1 minute. Tests conducted with the newly developed Tester gave penetration rates of more than 10 percent for several disposable dust respirators even when the subjects had fitted them carefully.
Journal of Science of Labour - Rōdō Kagaku, 10 Nov. 1991, Vol.67, No.11, p.517-524. 7 ref.
Harber P., Luo J., Beck J., Lee J.
Relative effects of flow-resistive and pressure-biased respiratory loading
The effects of pressure-biased breathing (PBB), which simulates positive pressure respirator use, were studied in 15 volunteer subjects during laboratory exercise. PBB was compared with inspiratory resistance: dead space (ID) load and a no-load (N) situation. PBB had adverse subjective effects comparable with those of ID. Physiologically, PBB led to a small decrease in inspiratory time and an increase in expiratory time as well as an increase in the intensity of ventilatory effort as measured by the mean inspiratory flow rate. It is postulated, based on these findings, that PBB has significant effects on the resting lung volume, leading to both physiological and subjective consequences.
Journal of Occupational Medicine, Oct. 1991, Vol.33, No.10, p.1055-1059. 14 ref.
Maclay G.J., Yue C., Findlay M.W., Stetter J.R.
A prototype active end-of-service-life indicator for respirator cartridges
The article presents a prototype AESLI (Active-End-of-Service-Life-Indicators) designed to be used with respirators protecting against organic vapours. The prototype device consists of a sensor that is to be located within the bed of the cartridge and is electrically connected to a signal-processing module located on the face mask. The small, low-power module causes a LED alarm to flash when the gas concentration reaches a preset threshold value. The LED is mounted on the mask, directly in front of the user, and is clearly visible when flashing; however, it does not obstruct vision. Locating the sensor within the filter protects the sensor from substances in the ambient air that do not pass directly through the cartridge bed during use, thus reducing the demand for sensor selectivity and protecting the sensor from exposure to the breath of the user.
Applied Occupational and Environmental Hygiene, Aug. 1991, Vol.6, no.8, p.677-682. Illus. 3 ref.
Coblentz R., Mollard R., Ignazi G.
Three-dimensional face shape analysis of French adults, and its application to the design of protective equipment
In a preliminary survey, anthropometric measurements were collected on 301 females and 208 males and a sampling strategy was designed to select 30 females and 30 males as test subjects. A stereophotogrammetric method was used for face data acquisition and stereorestitution was made on pairs of photographs placed in an analytical plotter. Three-dimensional values for each subject were processed using computer-aided design software and five groups of fore-faced size were identified. The study demonstrates that stereometric measurements of the face can be used as basic data for the design of protective equipment for the fore-face.
Ergonomics, Apr. 1991, Vol.34, No.4, P.497-517. Illus. 38 ref.
Modern overalls are important - Lead hazard due to sandblasting operations
Moderne Schutzanzüge sind wichtig - Bleigefährdung bei Strahlarbeiten [in German]
Cases of lead poisoning are described. They occurred among workers engaged in the sandblasting of bridge railings for corrosion protection. Blood lead levels and anamnestic details are presented. Blood lead levels reached 178µg/dL. Investigations of the causes led to untight protective clothing and sealing off of the work area to prevent environmental pollution.
Sicher ist Sicher, Mar. 1991, Vol.42, No.3, p.132-134.
Harber P., Beck J., Brown C., Luo J.
Physiologic and subjective effects of respirator mask type
The effect of alternate airflow path designs on full-face mask air-purifying respirators was assessed in 14 healthy volunteers during submaximal exercise. Respirator designs included no respirator (N), full-face mask, dual-cartridge with no nasal deflector (FN), full-face mask respirator with nasal deflector (FD), and a powered air-purifying respirator (PA). Physiologic effects were measured by using respiratory inductive plethysmography and subjective responses by two visual analog scales. There were significant effects of airflow path design upon the physiologic parameters of ventilation, tidal volume, and mean flow rate. There were no significant physiologic or subjective differences between the full-face mask respirators with and without the nasal deflector in place. The PA had less physiologic impact than the nonpowered models but did not show significant subjective benefit. The study suggests that both subjective and objective physiologic responses must be utilised in assessing respirator design.
American Industrial Hygiene Association Journal, Sep. 1991, Vol.52, No.9, p.357-362. Illus. 26 ref.
Crutchfield C.D., Eroh M.P., Van Ert M.D.
A feasibility study of quantitative respirator fit testing by controlled negative pressure
The feasibility of using a direct measure of respirator leakage flow rate as a quantitative index of respirator face seal fit is explored through a new controlled negative pressure method. The method is based on exhausting air from a temporarily sealed respirator facepiece at a rate sufficient to generate and sustain a constant negative pressure inside the facepiece while the wearer holds his breath. The feasibility of using the new method to quantify respirator fit was assessed by comparing its performance with a quantitative fit test method based on use of dichlorodifluoromethane as a challenge agent. There was a high degree of correlation (r > 0.99) and no significant difference between the two methods over a range of controlled mask leakage rates. However, the new method does not require a destructive sampling probe. Other benefits include (1) ease of test administration, (2) simplicity of test components, (3) lack of a potentially toxic challenge agent, (4) a straightforward calibration procedure, (5) multiple test capability, (6) immediacy of test results, and (7) field portability of the test system.
American Industrial Hygiene Association Journal, Apr.1991, Vol.52, No.4, p.172-176. Illus. 25 ref.
NIOSH certified equipment list as of December 31, 1990
This list is provided as part of the NIOSH testing, approval and certification programme for personal protective devices and industrial hazard measuring instruments (1989 list: see CIS 90-1311). Certified products listed include coal mine dust personal sampler units, self-contained breathing apparatus, gas masks, supplied air respirators, particulate respirators, chemical cartridges, powered air purifiers and vinyl chloride respirators. Brief technical details are given of each product listed, and names and addresses of manufacturers and distributors are provided.
US Department of Health and Human Services, Centers for Disease Control, National Institute for Occupational Safety and Health, 4676 Columbia Parkway, Cincinnati, OH 45226, USA, Jan. 1991. 498p.
Health and Safety Executive
Respiratory protective equipment (RPE) - Legislative requirements and lists of HSE approved standards and type approved equipment
This guidance document was previously issued by the Health and Safety Executive in 1989 (see CIS 90-1323). Contents: legislative requirements for the use of RPE in the United Kingdom, type approval certificates and user action; list of HSE-approved standards for RPE, annotated list of HSE-approved for RPE; annotated list of HSE-approved equipment; addresses of manufacturers and suppliers.
HMSO Books, P.O. Box 276, London SW8 5DT, United Kingdom, 1991. 45p. Price: GBP 2.25.
Yoon Y.H., Nelson J.H., Lara J., Kamel C., Fregeau D.
A theoretical interpretation of the service life of respirator cartridges for the binary acetone/m-xylene system
The study reports on the development of a theoretical model which predicts the service life of respiratory cartridges used in the presence of a mixture of pollutants. A model for two-component (binary) contaminant systems is applied to the acetone/m-xylene binary system. In such binary mixtures, the breakthrough curves of m-xylene are similar to corresponding single-component m-xylene systems. However, the breakthrough properties of acetone in the presence of m-xylene are different from those observed for acetone alone. A theoretical expression defines the breakthrough curve for acetone in the presence of m-xylene, which applies for varying assault concentrations of both acetone and m-xylene in the binary system. Values of required theoretical parameters are determined and used to calculate breakthrough curves for acetone in the binary system. These curves are compared with corresponding experimental data at several different assault concentrations. For the acetone/m-xylene binary system, the breakthrough time of acetone must be considered in order to estimate the service life of a cartridge simultaneously exposed to both vapours.
American Industrial Hygiene Association Journal, Feb. 1991, Vol.52, No.2, p.65-74. Illus. 12 ref.
Respirator safety - Respirator safety; The care and use of APR's
Sécurité des appareils de protection respiratoire - Sécurité des appareils de protection respiratoire; Entretien et utilisation des appareils respiratoires filtrants [in French]
Audiovisual series for training purposes. I - enumeration of respiratory hazards a worker might face; reasons for wearing respiratory protection equipment; types of equipment available. II - proper use and maintenance of air-purifying respirators; fit testing; regular inspection and fit checking before each use.
Tel-A-Train Inc., 309 N. Market Street, P.O. Box 4752, Chattanooga, TN 37405, USA, 1991. 2 videotapes (NTSC, PAL). Length: 16 + 13min. Employee's guide available.
Cohen H.J., Briggs D.E., Garrison R.P.
Development of a field method for evaluating the service lives of organic vapor cartridges. Part III, Results of laboratory testing using binary organic vapor mixtures
Results of a third study on the use of small, carbon-filled glass tubes, referred to as respirator carbon tubes (RCTs), for predicting the service lives of organic-vapour respirator cartridges are presented. The effects of binary organic vapour mixtures and intermittent testing on the predictive accuracy of the method were examined. The RCT method predicted cartridge breakthrough times to an accuracy of ± 17% at the 95% confidence level for n-hexane, pyridine, and binary mixtures of each with carbon tetrachloride in an approximately 50% RH environment. Estimated kinetic adsorption capacities for each adsorbate-carbon bed system tested were reduced when a second adsorbate was introduced at the same concentration. There was no evidence that n-hexane, carbon tetrachloride, or their mixtures exhibited migration through cartridges when exposed to a regime of testing to 50% of the breakthrough time, followed by a resting cycle of 4 days, and then a resumption of testing to breakthrough. A small, statistically insignificant reduction in breakthrough time was observed when cartridges were tested intermittently with pyridine. Simple treatment of mixtures based on data from single component testing may predict incorrect breakthrough times and support the need for a field method to estimate cartridge service lives.
American Industrial Hygiene Association Journal, Jan.1991, Vol.52, No.1, p.34-43. Illus. 30 ref.
Harber P., Brown C.L., Beck J.G.
Respirator physiology research: Answers in search of the question
Adverse effects of respirators have been the focus of considerable research over the past decade. Individual research projects have generally focused on one specific category of effects: ventilatory, respiratory control, work limitation, subjective discomfort, psychological effects, thermal loading, and cardiovascular changes. Most were studied in experimental laboratory situations rather than in actual worksites. Very little attention has been given to compliance with use and actual effectiveness in preserving health. Inasmuch as many types of effects have been demonstrated, there is a need to carefully define which type(s) of effects is/are most important for respirator design selection and worker medical certification in particular situations. In general, respirators should be assessed for their effect on all relevant variables.
Journal of Occupational Medicine, Jan.1991, Vol.33, No.1, p.38-44. 59 ref.
Respirators suitable for the transport of hazardous substances on roads
Geeigneter Atemschutz beim Transport gefährlicher Stoffe auf der Strasse [in German]
This review describes respirators available in Germany for drivers of trucks transporting dangerous substances and the legal requirements concerning them. It is concluded that both supplied air respirators with suitable filters and closed circuit breathing apparatuses comply with existing rules and regulations.
Verkehrs-Rundschau, Sep. 1990, No.39, p.47-53. Illus.
Löf A., Brohede C., Gullstrand E., Lindström K., Sollenberg J., Wrangskog K., Hagberg M., Kolmodin-Hedman B.
The effectiveness of protective respiratory masks during styrene exposure at a plastic boat factory
Andningsskyddens effektivitet vid styrenexponering på en plastbåtsindustri [in Swedish]
Attitudes to protective respiratory equipment and differences in exposure with and without protective equipment have been studied at a plastic boat factory. The workers used protective equipment as much as possible during the 1st day of the study and during the 2nd day only for short periods or not at all. Individual styrene exposures in the breathing zone were measured both inside and outside the protective equipment. Exposures were reduced by 56-92% when protective equipment was used. Urinary excretion rates of styrene metabolites, mandelic and phenylglyoxylic acids, collected after the workday, were reduced by 30-99%. The reasons given for not wearing protective equipment were that it delayed and interfered with the work, that it was too tight-fitting, rubbing the skin, and that it made breathing difficult and/or that it became too warm.
Arbetsmiljöinstitutet, Förlagstjänst, 171 84 Solna, Sweden, 1990. 25p. Illus. 35 ref.
Respiratory protective equipment against dust (RPE) - Comparison of subjective assessments of comfort and efficiency with the results of standardised tests - Practical considerations
Appareils de protection respiratoire contre les poussières - Comparaison de l'évaluation subjective avec les tests objectifs normalisés - Intérêt pratique [in French]
Subjective assessments of comfort and efficiency of respiratory protective equipment (RPE) against dust have been carried out in healthy volunteers during standardised inward leakage tests. The results show a clear-cut difference between two RPE classes, facepieces and filters (Pcart) and filtering facepieces (Ppap). Subjectively, Pcart were felt to be more efficient and less comfortable than Ppap. The comparison between subjective and objective efficiency shows that for Pcart subjective estimates have a good correlation with actual efficiency. For Ppap, whatever their measured leakage, subjective efficiency is always estimated as poor. Under the experimental conditions of this study, breathing is only slightly hampered by any RPE. The discomfort of Ppap is related to their reduced field of vision. The strap system is the main discomfort source of Pcart. These results have to be considered for dust RPE selection and user's information in order to improve the protection of workers.
Cahiers de notes documentaires - Sécurité et hygiène du travail, 4th Quarter 1990, No.141, Note No.1805-141-90, p.825-831. Illus. 31 ref.
Iversen M., Takai H.
Lung function studies in farmers during work in swine confinement units
Pulmonary function parameters were measured in 31 pig farmers before and after work. Five of these used a respirator on some days of the study. Average organic dust concentrations in the breathing zone of the farmers were 0.35-0.91mg/m3. 17 of 26 farmers had either shortness of breath or wheezing during work in swine confinement buildings; 9 of 16 were asymptomatic. Symptomatic farmers showed significant decreases in one-second forced expiratory volume (FEV1) and forced vital capacity (FVC), asymptomatic farmers in FEV1. The respirators had a slight positive effect.
Zentralblatt für Arbeitsmedizin, Arbeitsschutz, Prophylaxe und Ergonomie, 1990, Vol.40, No.8, p.236-242. Illus. 25 ref.
Respiratory protective equipment - A practical guide for users
Topics covered in this guide: legal requirements for respiratory protective equipment (RPE); assessment of RPE requirements and selection of appropriate type of equipment; types of RPE and their applications, including dust and gas respirators, supplied air equipment and breathing apparatus; personal and work-related factors; training in the use of RPE; correct methods of use, storage and maintenance of equipment. Descriptions and illustrations are given of a wide range of RPE.
HMSO Books, P.O. Box 276, London SW8 5DT, United Kingdom, 1990. 29p. Illus. Price: GBP 4.00.
Respiratory protective equipment: Legislative requirements and lists of HSE approved standards and type approved equipment
This guide lists relevant UK Regulations concerning the control of substances that cause damage to health and explains the duties placed on employers to ensure that respiratory protective equipment (RPE) is used in compliance with the Regulations. Two further lists provide details of the types of RPE which have been approved or for which standards have been approved by the UK Health and Safety Executive under the Regulations. Names and addresses of manufacturers and suppliers are also provided.
HMSO Books, P.O. Box 276, London SW8 5DT, United Kingdom, 1990. 34p. Price: GBP 2.00.
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