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Sensors

Sensors

 

Globe Thermometer

 

Sensors

Globe Thermometer

The globe thermometer (left position) gives an indication of the radiant heat exposure on an individual due to either direct sunlight or hot objects in the environment. This is accomplished by placing a temperature sensor inside a blackened copper sphere and measuring the temperature rise. The WBGT index is based on the response of a 6 inch diameter globe. The QUESTemp uses a 2 inch diameter globe for a faster response time. The temperature of the 2 inch globe is correlated to match that of a 6 inch globe.

Waterless Wetbulb & Relative Humidity Sensor

The relative humidity sensor (middle position) is used to calculate the Waterless Wetbulb from a combination of dry bulb temperature, humidity and wind speed measurements. The waterless wetbulb is used to calculate an estimated WBGT value.

Dry Bulb Thermometer

The dry bulb thermometer (right position) measures the ambient air temperature. This measurement is used in the outdoor WBGT calculation when a high solar radiant heat load may be present. The series of white plates surrounding the sensor shield it from radiant heat.

A B C

A. Globe thermometer

B. Relative humidity sensor

C. Dry bulb thermometer

Figure 1-8: Sensors identified

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3M 48N user manual Sensors, Globe Thermometer, Waterless Wetbulb & Relative Humidity Sensor, Dry Bulb Thermometer