Evaluation of Physiological Strain in Hot Work Areas Using Thermal Imagery

Details

• Personal Author:
  Handy R ; Holm CA ; Pahler L ; Thiese MS
• Description:
  Background: Monitoring core body temperature to identify heat strain in workers engaged in hot work in heat stress environments is intrusive and expensive. Nonintrusive, inexpensive methods are needed to calculate individual Physiological Strain Index (PSI). Objective: Thermal imaging and heart rate monitoring were used in this study to calculate Physiological Strain Index (PSI) from thermal imaging temperatures of human subjects wearing thermal protective garments during recovery from hot work. Methods: Ten male subjects were evaluated for physiological strain while participating in hot work. Thermal images of the head and neck were captured with a high-resolution thermal imaging camera concomitant with measures of gastrointestinal and skin temperature. Lin's concordance correlation coefficient (rho_c), Pearson's coefficient (r) and bias correction factor (C-b) were calculated to compare thermal imaging based temperatures to gastrointestinal temperatures. Calculations of PSI based thermal imaging recorded temperatures were compared to gastrointestinal based PSI. Results: Participants reached a peak PSI of 5.2, indicating moderate heat strain. Sagittal measurements showed low correlation (rho_c=0.133), moderate precision (r=0.496) and low accuracy (C_b=0.269) with gastrointestinal temperature. Bland-Altman plots of imaging measurements showed increasing agreement as gastrointestinal temperature rose; however, the Limits of Agreement (LoA) fell outside the +/- 0.25 C range of clinical significance. Bland-Altman plots of PSI calculated from imaging measurements showed increasing agreement as gastrointestinal temperature rose; however, the LoA fell outside the +/- 0.5 range of clinical significance. Conclusion: Results of this study confirmed previous research showing thermal imagery is not highly correlated to body core temperature during recovery from moderate heat strain in mild ambient conditions. Measurements display a trend toward increasing correlation at higher body core temperatures. Accuracy was not sufficient at mild to moderate heat strain to allow calculation of individual physiological stress. [Description provided by NIOSH]
• Subjects:
  Heat Stress Disorders Hot Temperature Occupational Health Safety Temperature
• Keywords:
  Author Keywords: Heat Strain Body Temperature Core Temperature Heat Stress Hot Environments Hot Work Imaging Techniques Physiological Effects Physiological Strain Index Temperature Effects Thermal Imaging

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• ISSN:
  0306-4565
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  OSHA Region 8 ; Utah
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  8-15
• Volume:
  61
• NIOSHTIC Number:
  nn:20067338
• Citation:
  J Therm Biol 2016 Oct; 61:8-15
• Contact Point Address:
  Clint A. Holm, Rocky Mountain Center for Occupational and Environmental Health, Department of Family and Preventative Medicine, School of Medicine, University of Utah, Salt Lake City, UT, USA
• Email:
  clint.holm@utah.edu
• Federal Fiscal Year:
  2017
• Performing Organization:
  University of Utah
• Peer Reviewed:
  True
• Start Date:
  20050701
• Source Full Name:
  Journal of Thermal Biology
• End Date:
  20280630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:6479e3dbfd92096e37ab72710f5728a247dd8dc68fce4cf3274f9619b6d88a07dc23ff4c20701b350c34629d40e4fe6c9cc853303b96a6167c63b531fa52518b
• Download URL:
  https://stacks.cdc.gov/view/cdc/230881/cdc_230881_DS1.pdf
• File Type:
  [PDF - 1.58 MB ]