Heat strain assessment for workers using an encapsulating garment and a self-contained breathing apparatus /
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| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1991.
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| Subjects: | |
| Online Access: | Link to OAKTrust copy |
| Abstract: | This study evaluated physiological responses to four environmental conditions while subjects wore a Tyvek® Saranex® totally encapsulating suit and a self-contained breathing apparatus. The work, maintained at 220 kcal/h, was performed on an ergometer. Five young male cyclists (mean age = 28.7 years), performed in five environmental conditions, including a control session without heat stress, in a randomized series. Each session was conducted in an environmental chamber and was scheduled to last 90 minutes, that is, three periods composed of 25 minutes of work followed by a five-minute rest period. Physiological measurements included heart rate, six-point skin temperature, and rectal temperature. The dry bulb temperature (T-[db]) was varied from 20.5 °C to 32.5 °C and globe temperature (T[g]) from 30.5 °C to 40 °C. Air velocity was constant at 1 m/sec and relative humidity maintained between 35% and 45%. Measurement of all parameters were obtained every two minutes until each session terminated. This study shows that the known empirical indices can not be adapted to encapsulated work. Mean rise in rectal temperature varied from 0.28 °C (T[db] = 30.5 °C and T[g] = 30.5 °C) to 1.30 °C (T[db] = 32.5 °C and T[g] = 40 °C). It appears that heart rate and skin temperature are closely correlated with the rise in rectal temperature. A regression model using environmental parameters along with time yielded a coefficient of correlation (R^2) = 0.77. The addition of heart rate and skin temperature at the chest as predicting variables yielded an R^2 = 0.82. Different regression models can better predict heat strain under different environmental conditions. Also, the use of heart rate can be sufficient to take into account individuals' variability in tolerance to heat stress. Exposing encapsulated workers to a higher stress than 32.5 °C dry bulb and 40 °C globe temperatures is very hazardous. The range of interest between a no-harm and a maximum permissible heat stress level is very narrow. A heat exposure assessment program using four prediction models is proposed. The results are further discussed and recommendations are formulated. |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Industrial Engineering." |
| Physical Description: | xi, 150 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |