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Results for “Respiratory Protective Devices”

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At least 19 recordsLinked to original sources
PubMed1990

Thermal discomfort of respiratory protective devices.

Respiratory protective devices which would protect the wearer against noxious material and gases are not worn in many of the appropriate circumstances. They have been said to feel uncomfortable and hot. In the present study, six men and six women in a 25 degrees C room reported on facial discomfort, thermal sensation, and sweating while wearing three different types of half-facepiece respirators requiring tidal airflow. Skin temperature of the face was measured using a thermocouple taped to the nasolabial fold. The subjects reported that the face felt comfortable when the skin temperature was 34 degrees C or below. However, at skin temperatures above 34.5 degrees C, the face felt increasingly warm, uncomfortable, and sweaty. This finding is similar to that reported previously when subjects wore a half-facepiece respirator supplied continuously with warm, humid air. The conclusion is that thermal conditions of the face contributed to, and may possibly dominate, the discomfort of wearing respiratory protective devices.

Adult↗
PubMed1977

Minimum protection factors for respiratory protective devices for firefighters.

Carbon monoxide and oxygen concentrations were measured in seventy-two structural fires using a personal air sampler carried by working firefighters. In a total sampling time of 1329 minutes the carbon monoxide concentration exceeded 500 ppm approximately 29 percent of the time. The maximum carbon monoxide concentration was 27,000 ppm and in 10 percent of the fires, the maximum concentration exceeded 5500 ppm. Only six runs indicated oxygen concentrations less than 18 percent. On the basis of these exposure data, a minimum protection factor of 100 is proposed for breathing apparatus for structural firefighting.

Air↗
PubMed1989

Effect of thermal conditions on the acceptability of respiratory protective devices on humans at rest.

The physiological and subjective responses of six sedentary subjects wearing half-facepiece respirators were observed over a wide range of room and respirator air conditions. Room air and dew-point (Ta:Tdp) temperatures were 25:11 degrees, 30:13 degrees, and 35:16 degrees C in still air. Respirator air temperatures were maintained independently of room conditions at 27 degrees, 30 degrees, 33 degrees, and 36 degrees C with relative humidity levels of 47% and 73%. Physiological measurements included local skin and dew-point temperatures. Subjective judgments of acceptability, thermal sensation, degree of discomfort, sense of skin moisture, and difficulty of breathing were recorded separately for the thermal environment in the room and inside the respirator. Respirator temperatures cooler than 33 degrees C were always comfortable and 100% acceptable; respirator air temperatures above 33 degrees C or higher humidity levels decreased respirator acceptability. Acceptability of the respirator environment decreased as lip temperature increased above 34.5 degrees C or when respirator dew-point temperature increased above 20 degrees C. Increased respirator air temperature and humidity often made breathing seem "slightly hard." The respirator conditions influenced the subjects' judgment of the acceptability of the surrounding thermal environment.

Adult↗
PubMed1978

[Selection of suitable individual respiratory protective devices in relation to workroom environment].

Adopting individual respiratory protective equipments, even if in those limited situations in which they are justified, must be consequent to a selection related with the nature of the pollutants to which the operator is, or may be, exposed, with the peculiarity of the workroom environment and, lastly, with the degree of security to be achieved. This statement is not to be neglected even if all respiratory protective equipments are fit to meet the suggestions of qualified standard making institutions. The same is to be considered of capital importance in Italy where the lack of legislation as far as omologation is concerned, allows products not fit to guarantee the request for security which are, consequently, not only superfluous, but dangerous for wearers. For these reasons it has been considered useful to illustrate the characteristics and proper application-fields of the most widely spread respiratory protective equipments referring, as far as possible, to the recommendations being prepared on the matter by the CEN (European Committee for Standardization).

Air Pollutants↗
PubMed1990

[Comparison of the protective action of 2 respiratory protective devices in farmers with farmer's lung].

With the aid of provocative challenges with hay in patients suffering from farmer's lung, a comparison of the protective effectiveness of the Airstream Helmet (main filter P2) and of the Sundström Mask (main filter P3) was undertaken. A total of 42 farmers were admitted to the study. In 14, as indicated by an expertise, a workplace-related provocative challenge by the farmers' own hay was carried out and was shown to be positive with respect to the presence of farmer's lung disease. In 28 farmers in whom an inhalative provocative challenge with hay had been demonstrated to be positive, inhalative provocative challenges were again performed using the farmers' own hay while the farmers were wearing protective respirators--14 with the Airstream Helmet, (main filter P2) and 14 with the Sundström Mask (main filter P3). When the respirator was not worn, a statistically significant increase in the number of leukocytes and temperature vis-a-vis the baseline values was observed. Partial oxygen pressure, vital capacity, total lung capacity and DCO, all showed a statistically significant decrease as compared with the baseline figures. The provocative challenges performed while the subjects were wearing the respirators also revealed a statistically significant increase in the number of leukocytes and in temperature, which, however, was statistically significantly smaller than that induced by provocation without the respirator. A similar pattern of behaviour was also found in the decrease in vital capacity, oxygen partial pressure, total lung capacity and DCO. No statistically significant differences were observed between the provocation figures obtained with the Airstream Helmet as compared with those obtained with the Sundström Mask.(ABSTRACT TRUNCATED AT 250 WORDS)

Bronchial Provocation Tests↗
PubMed1991

Psychological effects on prolonged use of respiratory protective devices in children.

In the study of psychological effects of prolonged use of a respiratory protective device (RPD), forty 7-10-year-olds, fifty 12-15-year-olds and twenty-eight 17-20-year-olds participated as subjects. Subjects in the experimental groups wore a full-face mask provided for civil defence in Sweden, and subjects in the control groups wore a filtering facepiece consisting of a tissue material covering the nose and mouth. Subjects in both groups tended to terminate at the same time, implying that breathing resistance may not be an important obstacle to prolonged wear of the full-face mask. In the experimental groups 97% wore the mask for at least 1.5 h, 77% for at least 2.5 h and 54% for the full 6-h session. About 50% of subjects in the younger age groups terminated in the interval between 1.5 to 3.5 h, whereas the corresponding figure in the older age group was about 30%. Boredom may have played an important role for decisions to terminate, perhaps in part because the mask interfered with speech communication. Discomfort due to pressure on the nose, the chin and the forehead was also reported, more frequently by the older than by the younger subjects.

Adolescent↗
PubMed1992

The effects of powered air supply to the respiratory protective device on respiration parameters during rest and exercise.

The common chemical warfare protective masks impose an excessive respiratory load on the wearer due to elevated breathing resistance and increased dead space. For patients with severe respiratory disease, the excessive respiratory effort may be intolerable. Besides, the substantial negative pressure created within the mask during inspiration may result in an inward leakage in individuals having difficulties with proper facial fitting of the mask. The purpose of the current investigation was to evaluate the effects of a blower, actively driving air, through the mask's filter, at a flow (mean +/- SD) of 42 +/- 2 L/min, on respiratory parameters during rest and moderate exercise. Ten healthy subjects of either sex participated in two experimental sessions, wearing the mask with and without the blower. Each session included 6 min of sitting at rest and 6 min of walking on a treadmill (3.2 mph, and 10 percent grade). In nine of the subjects, the active air supply produced a positive inspiratory pressure at rest (5 +/- 4 vs -24 +/- 9 mm H2O peak inspiratory pressure with and without the blower, respectively, p < 0.0001). Inspiratory carbon dioxide concentration (FICO2) at rest was diminished (0.4 +/- 0.4 vs 1.3 +/- 0.7 percent with and without the blower, respectively; p < 0.01) while FIO2 increased from 19.5 +/- 0.7 percent to 20.6 +/- 0.4 percent with the device (p < 0.01). These changes were associated with a significant decrease in respiratory rate (15 +/- 2 vs 18 +/- 3 per minute, p < 0.01). During exercise the blower barely decreased the negative inspiratory pressures, had no effect on other respiratory parameters measured, but significantly shortened the inspiratory/cycle-length time ratio (0.46 +/- 0.03 vs 0.53 +/- 0.03, p < 0.005). The effects of active air supply were not different between male and female subjects. We conclude that the blower is expected to be a useful accessory to respiratory protective devices for patients with pulmonary disease.

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↗
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↗
PubMed1979

Respirator use and protection from exposure to carbon monoxide.

Investigations of the protective effect afforded by respirators in Baltimore firefighters are presented. The data indicates that the continuous use of respirators offers significant protection from exposure to carbon monoxide but that this protection is not absolute. A surprising finding is that the intermittent use of the face mask offers as little protection to the men as does non-use. These findings emphasize the difficulties in relying upon respiratory personal protective equipment for protection from exposure.

Adult↗