Heat Stress Assessment During Intermittent Work Under Different Environmental Conditions and Clothing Combinations of Effective Wet Bulb Globe Temperature (WBGT)

Details

• Personal Author:
  Kenny GP ; Kim J-H ; Powell J ; Roberge R ; Seo Y ; Strauch A
• Description:
  This study examined whether different combinations of ambient temperature and relative humidity for the effective wet bulb globe temperature, in conjunction with two different levels of clothing adjustment factors, elicit a similar level of heat strain consistent with the current threshold limit value guidelines. Twelve healthy, physically active men performed four 15-min sessions of cycling at a fixed rate of metabolic heat production of 350 watts. Each trial was separated by a 15-min recovery period under four conditions: (1) Cotton coveralls+dry condition (WD: 45.5 degree Celsius dry-bulb, 15% relative humidity); (2) Cotton coveralls+humid condition (WH: 31 degree Celsius dry-bulb, 84% relative humidity); (3) Protective clothing+dry condition (PD: 30 degree Celsius dry-bulb, 15% relative humidity); and (4) Protective clothing+humid condition (PH: 20 degree Celsius dry-bulb, 80% relative humidity). Gloves (mining or chemical) and headgear (helmet or powered air-purifying respirator) were removed during recovery with hydration ad libitum. Rectal temperature (Tre), skin temperature (Tsk), physiological heat strain (PSI), perceptual heat strain (PSI), and body heat content were calculated. At the end of the 2-hr trials, Tre remained below 38 degree Celsius and the magnitude of Tre elevation was not greater than 1 degree Celsius in all conditions (WD: 0.9, WH: 0.8, WH: 0.7, and PD: 0.6 degree Celsius). However, Tsk was significantly increased by approximately 2.1 +/- 0.8 degree Celsius across all conditions (all p≤0.001). The increase in Tsk was the highest in WD followed by PD, WH, and PH conditions (all p≤0.001). Although PSI and PeSI did not indicate severe heat strain during the 2-hr intermittent work period, PSI and PeSI were significantly increased over time (p≤0.001). This study showed that core temperature and heat strain indices (PSI and PeSI) increased similarly across the four conditions. However, given that core temperature increased continuously during the work session, it is likely that the American Conference of Governmental Industrial Hygienist's TLVVR upper limit core temperature of 38.0 degrees Celsius may be surpassed during extended work periods under all conditions. [Description provided by NIOSH]
• Subjects:
  Environment Heat Stress Disorders Hot Temperature Humidity Occupational Health Personal Protective Equipment Protective Clothing Safety Temperature
• Keywords:
  Author Keywords: Heat Stress Clothing Environmental Factors Gloves Headgear Heat Exposure Heat Stress Intermittent Work Physiological Effects Temperature Effects Threshold Limit Values TLV Wet Bulb Globe Temperature

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• ISSN:
  1545-9624
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  OSHA Region 3 ; Pennsylvania
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  NPPTL - National Personal Protective Technology Laboratory
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  467-476
• Volume:
  16
• Issue:
  7
• NIOSHTIC Number:
  nn:20055920
• Citation:
  J Occup Environ Hyg 2019 Jul; 16(7):467-476
• Contact Point Address:
  Jung-Hyun Kim, Department of Sports Medicine, College of Physical Education, Kyung Hee University, 1732 Deogyeong-daero, Giheung-gu, Yongin, 17104, South Korea
• Email:
  junghyun.kim@khu.ac.kr
• Federal Fiscal Year:
  2019
• NORA Priority Area:
  Public Safety
• Peer Reviewed:
  True
• Source Full Name:
  Journal of Occupational and Environmental Hygiene
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:2eb7ade93ca88e00d65d1f4031e6e4cf316001e38341e12bee08d4390a7fcfaa3d989e3493512e0a142eb2095e98b23964b317e1a617121735b8e7e209a34f22
• Download URL:
  https://stacks.cdc.gov/view/cdc/213672/cdc_213672_DS1.pdf
• File Type:
  [PDF - 1.18 MB ]