title: Validating the Heat Stress Indices for Using In Heavy Work Activities in Hot and Dry Climates.
abstract: BACKGROUND
  Necessity of evaluating heat stress in the workplace, require validation of indices and selection optimal index. The present study aimed to assess the precision and validity of some heat stress indices and select the optimum index for using in heavy work activities in hot and dry climates.
  
  
  METHODS
  It carried out on 184 workers from 40 brick kilns workshops in the city of Qom, central Iran (as representative hot and dry climates). After reviewing the working process and evaluation the activity of workers and the type of work, environmental and physiological parameters according to standards recommended by International Organization for Standardization (ISO) including ISO 7243 and ISO 9886 were measured and indices were calculated.
  
  
  RESULTS
  Workers engaged in indoor kiln experienced the highest values of natural wet temperature, dry temperature, globe temperature and relative humidity among studied sections (P<0.05). Indoor workplaces had the higher levels of all environmental parameters than outdoors (P=0.0001), except for air velocity. The wet-bulb globe temperature (WBGT) and heat stress index (HSI) indices had the highest correlation with other physiological parameters among the other heat stress indices. Relationship between WBGT index and carotid artery temperature (r=0.49), skin temperature (r=0.319), and oral temperature (r=0.203) was statistically significant (P=0.006).
  
  
  CONCLUSIONS
  Since WBGT index, as the most applicable index for evaluating heat stress in workplaces is approved by ISO, and due to the positive features of WBGT such as ease of measurement and calculation, and with respect to some limitation in application of HSI; WBGT can be introduced as the most valid empirical index of heat stress in the brick workshops.
authors: Occupational Health Research Center, Qom University of Medical Sciences, Qom, Iran.
authors: Roohalah
authors: R
authors: Hajizadeh
authors: Department of Occupational Health, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran. fgolbabaei@sina.tums.ac.ir.
authors: Farideh
authors: F
authors: Golbabaei
authors: Department of Occupational Health, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
authors: Somayeh
authors: S
authors: Farhang Dehghan
authors: Department of Occupational Health, Faculty of Health, Gonabad University of Medical Sciences, Gonabad, Iran.
authors: Mohammad Hossein
authors: MH
authors: Beheshti
authors: Department of Occupational Health Engineering, Faculty of Medicine, Khatam Al-Nabieen University, Kabul, Afghanistan.
authors: Sayed Mohammad
authors: SM
authors: Jafari
authors: Expert of Occupational Health Research Center, Iran University of Medical Sciences, Tehran, Iran.
authors: Fereshteh
authors: F
authors: Taheri
mesh_terms: D000388:Air; D001831:Body Temperature; D002339:Carotid Arteries; D002980:Climate; D004784:Environmental Monitoring / Q000379:methods*; D018882:Heat Stress Disorders / Q000209:etiology*; D006358:Hot Temperature; D006801:Humans; D006813:Humidity; D007492:Iran; D009055:Mouth; D009784:Occupational Diseases / Q000209:etiology*; D016273:Occupational Exposure / Q000009:adverse effects*; D015203:Reproducibility of Results; D012867:Skin; D014937:Work
keywords: Environmental parameters; Heat stress index; Physiological responses; Validation