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Use of swallowable core body temperature sensors and other measures to evaluate heat stress and strain among U.S. Air Force fuel systems maintenance employees.

Krake-A; King-B
American Industrial Hygiene Conference and Exposition, May 8-13, 2004, Atlanta, Georgia. Fairfax, VA: American Industrial Hygiene Association, 2004 May; :54
Heat stress evaluations were conducted at seven southern/southwestern U.S. Air Force (USAF) bases as part of a collaborative study of USAF employees’ acute exposure to jet fuel. USAF recruits employed as aircraft fuel systems maintenance inspection and repair workers were exposed to hot working conditions in confined spaces (aircraft fuel tanks) while wearing PPE. The potential for developing heat strain prompted USAF health and safety managers to request a heat stress evaluation. NIOSH investigators evaluated heat stress and strain using swallowable core body temperature (CBT) sensors, external heart rate (HR) monitors, and wet bulb globe temperature (WBGT) monitors. Pre- and post-shift body weight comparisons were also made on 50% of the employees. Job activities were analyzed according to metabolic heat production estimates. ACGIH suggests a maximum CBT of 101.3 F for medically selected, acclimatized personnel and 100.4 F for unselected, unacclimatized personnel. For individuals with normal cardiac performance, sustained HR (over several minutes) should not exceed 180 beats per minute minus age. And, because there is a greater risk of heat strain if profuse sweating is sustained over hours, weight loss over a shift should not exceed 1.5% of body weight. NIOSH work/rest regimen tables were used to plot the estimated metabolic heat against the environmental heat measurements. WBGT temperatures at all locations ranged from 53-93 F outdoors and from 60-88 F indoors and indicated that employees were exposed to heat stress conditions in excess of the NIOSH and ACGIH screening criteria for acclimatized individuals. Physiological sampling results indicated that about 25% of the study participants experienced heat strain signs (HR and/or CBT in excess of ACGIH criteria), and that 62% of those weighed developed at least mild dehydration during their activities. Recommendations were made to develop physiological monitoring programs and heat stress management and illness surveillance systems.
Heat-stress; Fuels; Maintenance-workers; Jet-engine-fuels; Exposure-levels; Occupational-exposure; Work-environment; Aircraft; Aircraft-engines; Physiological-testing; Physiological-factors; Sampling; Confined-spaces; Protective-equipment; Personal-protective-equipment
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American Industrial Hygiene Conference and Exposition, May 8-13, 2004, Atlanta, Georgia