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At least 55 records · Page 3Linked to original sources
PubMed1995

Respiratory protection devices.

OSHA authority and responsibility have led to the requirement that health care workers potentially exposed to patients with active tuberculosis in situations where engineering controls are not feasible for protection must utilize personal protective equipment at least equivalent to HEPA respirators. ICPs generally believe that this approach is unnecessarily conservative and imposes undue burdens on patient care. The arguments on both sides of this controversy have some merit. Reported cases of tuberculosis and skin-test conversions among health care workers since 1988 and the absence of a demonstrated safe level of exposure have led many to the conclusion that HEPA respirators are justified. On the other side, tuberculosis currently is not a major problem in some areas of the country, and many believe that less stringent personal protective devices (e.g., DM respirators) may provide protection equivalent to HEPA filters--at least in terms of preventing infection if not in terms of filtration efficiency. They believe that the lesser discomfort and lower cost associated with DM respirators justify the argument for a more flexible standard. Perhaps additional research can help to resolve the remaining controversy. Definitive answers are unlikely to surface quickly, however, and it is likely that the controversy and confusion will continue for at least awhile longer.

Health Personnel↗
PubMed1984

Physiological effects of pressure demand masks during heavy exercise.

Inward leakage in a respiratory protective device may constitute a health hazard. The pressure demand system causes a slightly positive pressure in the facepiece throughout the breathing cycle, so that any insufficient seal in such a system will result in an outward leakage. One question is whether this positive pressure will influence work capacity. Five subjects worked until exhaustion on a bicycle ergometer with four different breathing equipments: two masks with positive pressure (0.5 kPa and 0.8 kPa) and two mouthpieces without positive pressure, one control and one with high resistance. No difference in endurance time was found. Heart rate, oxygen consumption, rated perceived exertion and blood lactate at breaking point did not show any significant changes. The high resistance mouthpiece, -1.1 kPa to +1.3 kPa, at breaking point, did reduce minute ventilation by 21% and end tidal PCO2 was increased by 16% without any influence on work performance.

Adult↗
PubMed1989

A study on the usage of respirators among granite quarry workers in Singapore.

The frequency and correctness of respirators were studied in 5 granite quarries in Singapore involving 201 workers. The overall prevalence of usage of correct respirators was 45.8%. 10.4% of the workers were found to be using the wrong respiratory protective devices. Age, years of exposure and types of occupations were found to affect the usage of respirators. Some common reasons given by workers for not wearing the respirators were 'breathing difficulty', 'hot & sweaty', and 'respirator smells after a while'.

Adult↗
PubMedDate not supplied

The effects of protective equipment on styrene exposure in workers in the reinforced plastics industry.

This study was designed to determine whether styrene absorption through the skin results in measurable changes in biologic indicators of styrene exposure using a group of workers engaged in hand lay-up operations during which extensive styrene skin contact occurs. Serial measurements of expired breath and blood styrene and urinary excretion of mandelic and phenylglyoxylic acid were made in eight female workers during 4 consecutive days using different experimental conditions including either (1) gloves/protective clothing alone, (2) respirator alone, (3) both gloves/protective clothing and respirator, or (4) neither respirator nor gloves/protective clothing. A two-by-two factorial design imbedded in a Latin square design allowed estimation of the effects of the two types of protection (i.e., gloves/clothing and respiratory) and any interaction. Levels of styrene in venous blood and expired breath and urine mandelic and phenylglyoxylic acid excretion were no different when gloves/clothes were used as protection compared to no protection at all. Significant reduction in all biologic indices occurred when respiratory protection was used. The results of the study suggest that percutaneous absorption of styrene is not a significant exposure source and does not significantly contribute to the body burden of styrene of workers in the reinforced plastic industry engaged in hand lay-up operations. Respiratory protective devices were the most effective means for reducing styrene absorption. Even though skin absorption of styrene is limited, skin protection is necessary because of the risk of dermatitis.

Air Pollutants, Occupational↗
PubMed1981

[Optimal physiological parameters of respiratory tract protective devices].

The studies have been aimed at the evaluation of the effects of the use of purifying and insulating equipment of the respiratory system upon some physiological reactions. Also optimum physiological parameters for the respiratory tract safety equipment have been set up. The value of air flow resistance measured at constant air flow rate of 30 l/min should not exceed 10 mm H2O in the inhaling phase and 4 mm H2O in the exhaling phase. The dead space of the safety equipment should not exceed 150 ml, whereas CO2 concentration in the inhaled air -- 0.4%. The air flow rate should amount to 9 -- 12 m3/h during light physical effort of 48 Watt and 12 m3/h during moderately hard physical effort of 96 W. Air temperature in the facial part should be 19 -- 25 degrees C.

Adult↗
PubMed1988

Evaluation of comfort and seal leakages of several respirators used in agricultural work.

Certain aspects in the use of some respiratory protective devices were studied under laboratory and field conditions. The face seal leakages of these devices were measured and volunteers were interviewed about their subjective opinions on the use of the devices. Twelve men and five women participated in the study. The models tested were Silner 12, Siltox, Sundstrom SR 62/80, Airstream Breath Easy 2, Pirelli, and 3M (8810 P2, disposable) which are used in agricultural work in Finland. According to the study's results, these four models significantly differed from each other regarding the facial seal leakage (p less than 0.01). The Silner 12 had the greatest seal leakage (5.9% with men and 5.2% with women). The subjects felt that these respiratory protective devices were not cumbersome in their agricultural work or in the laboratory tests. The comfort of these devices in practical work was about the same for all models. Powered filtering hoods were more pleasant to use than mechanical ones because they offered less breathing resistance. The volunteers complained that with the Breath Easy 2 they felt drafts on the backs of their heads, especially while working in cool weather.

Adult↗
PubMed1979

An evaluation of respirator canisters to acrylonitrile vapors.

Experimental breakthrough times obtained from evaluating respiratory canisters to acrylonitrile vapors at various concentrations are presented and compared to estimated breakthrough times calculated from Nelson's equation for organic vapors adsorbed on activated carbon. The slope of the regression for breakthrough time vs. concentration of acrylonitrile was found to compare closely to that derived from Nelson's equation in the concentration range from 30 to 1000 ppm. This demonstrates that the equation is capable of predicting breakthrough times for organic compounds which, like acrylonitrile, have low molecular weights and boiling points. This ability to predict service life is also influenced by other important factors such as relative humidity and amount of activated carbon packed in a canister. Results of this evaluation illustrate the need to determine breakthrough times for compounds under controlled conditions similar to those encountered in the field, especially at low concentrations. Industrial hygienists should use experimentally derived breakthrough times to predict the service life of an air purifying device if they are available.

Acrylonitrile↗