The WBGT is a compact site monitoring instrument designed to help identify the problems of heat stress that are common in a variety of work places including: foundries, steel mills, glass and ceramic factories, power stations and mines, as well as many types of outdoor work. The instrument is designed to calculate and display the Wet Bulb Globe Temperature Index (WBGT), which was originally developed to provide a simple method of assessment of heat stress among military personnel. Whenever heat stress is imposed upon the human body, the resulting strain may result in physiological reactions such as sweat production, increased heart rate and higher core body temperature (i.e. ‘heat stress’). Greater levels of heat stress under certain conditions can be dangerous to human health. The MICROTHERM Heat Stress WBGT displays heat exposure values in ÞC WBGT (wet, dry and globe temperature). The unit may also be used to help with compliance to the new ISO 9920 - Ergonomics of the Thermal Environment and ISO 8996 - Ergonomics of Metabolic Heat Production. A membrane keypad controls On/Off, Select and Max reading functions, while a serial output socket (RS232) is provided for data transfer to a PC. A comprehensive software package displays Dry, Wet and Globe Temperature readings, and WBGT Indoor and Outdoor values. The program calculates and displays dew point, humidity and vapor pressure with the capability of archiving all information.