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Results for “Protective Devices”

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At least 19 recordsLinked to original sources
PubMed1975

The effectiveness of hearing protective devices.

The effectiveness of a hearing conservation program, and specifically the effectiveness of hearing protection devices (muffs in this case), was investigated over a five-year period, since the inception of the program at a major plant of the Ingersoll-Rand Company. The study concentrated on three groups (Class I, II, and III) of 213 employees whose noise level exposure did not change during the five-year study period. A hearing conservation criterion of 90dBA was utilized. One group consisted of office workers in which the level was well below this, a second group from a machine shop in which the level was slightly below the criterion, and a third group from foundry areas in which the levels were considerably above the 90dBA level. Personal ear protection was worn during the study period only by the last group. The mean differences in hearing levels were insignificant and were essentially the same in the three groups, at each frequency, and regardless of the baseline hearing thresholds. It is apparent that there were no significant changes in hearing threshodls during the study period among a non-noise exposed group; a mild to moderate noise-exposed group; and a group exposed to high levels of steady state noise, but wearing ear protectors. These results indicate that a hearing conservation program which includes audiometric testing and personal ear protection, utilizing a hearing conservation criterion of approximately 90dBA, does adequately protect the hearing of noise-exposed workers.

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↗
PubMed1976

[Possibilities of the biophysical evaluation of the efficiency of vibration protection devices for the hands].

The possibility of quantitative assessment of the efficiency of hand vibratory-protective devices using a physiological parameter--the loss of vibrosensitivity in the right-hand fingers depending on the intensity of vibration effect--is discussed. The results of the experiments prove that in case of vibration effect at frequency 31--500 Hz, the changes in vibrosensitivity threshold might be employed as an experimental method of assaying the efficiency whenever it exceeds two decibels.

Biomechanical Phenomena↗
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↗
PubMed1978

[Effectiveness of ear protective devices].

Efficiency of 9 types of hearing protectors was investigated. A subjective method of an absolute hearing threshold shift in free sound field in 20 well-hearing-persons was applied. The results obtained are presented in figures. It was found that the maximum efficiency of most hearing protectors usually fell toon the frequency of 4000 Hz and amounted to 20--41 dB. The minimum efficiency usually fell to the frequency of 125 Hz and amounted to 8--21 dB. Attenuation efficiency of broad-band noise was 18-40 dB and approximated the maximum efficiency of pure sounds, sometimes even surpassing it. The results of determinations differed from the values given by manufacturers, which accounts for the need of undertaking such investigations.

Ear Protective Devices↗