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Wet Bulb Black Globe Thermometer 40mm (WBGT8758) Heat Index

Model #: WBGT8758

UPC: 681035087589

Condition: New


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Wet Bulb Globe Temperature (WBGT) is a composite temperature used to estimate the effect of temperature, humidity, and solar radiation on humans. This instrument determines true heat stress temperature by accounting for air currents, relative humidity and solar load in addition to air temperature and relative humidity making this instrument ideal for industrial hygienists, athletic trainers, the military and the sports medicine environment.


  • Heat stress index (WBGT), ambient temperature and humidity in one handy meter
  • Direct measurement of radiation utilizing 40mm black bronze ball
  • Adjustable audible alarm for thermal condition monitoring
  • Audible beeper for heat stress monitoring
  • Low battery indicator
  • Can be switched between °F/°C
  • Sliding sensor cover sheath
  • Tripod mountable
  • RS-232 data output (9600 BPS, 8 data bits, no parity)
  • Auto power off (can be disabled)
  • Can be user calibrated using 33% (HR33) and 75% (HR75) humidity standards (sold separately)
  • Weighs less than 4 ounces
  • Measures:
    • Wet Bulb Globe Temperature (WBGT) a commonly used heat stress indicator that considers the effects of temperature, humidity and radiant energy.
    • Black Globe Temperature (TG) measured by the black globe thermometer, which monitors the effects of direct solar radiation on an exposed surface
    • Ambient Air Temperature (TA) measured in shade
    • Relative Humidity (%RH)
    • IN/OUT: Represents the measuring environment that is with or without direct sun exposure and display corresponding


  • Air temperature range in shade (TA): 32° to 122°F (0° to 50°C)
  • Air temperature accuracy: ±0.6°C
  • Black globe temperature range: 32° to 176°F (0° to 80°C)
  • Globe temperature accuracy:
    • Indoor:
      • ±2°C from 15 ~ 40°C
      • ±2.5°C other ranges
    • Outdoor:
      • ±3°C from 15 ~ 40°C
      • ±3.5°C other ranges
  • WBGT Temperature range: 32° to 122°F (0° to 50°C)
  • WBGT Temp accuracy: ±2°C
  • Temperature resolution: 0.1° C/F
  • WBGT values using the following equations:
    • Indoor/outdoor no sun: WBGT=0.7 WB + 0.3 TG
    • Outdoor or full sun: WBGT=0.7 WB + 0.2 TG + 0.1 TA
  • Relative Humidity range: 0 to100% RH
  • Relative Humidity accuracy:
    • ±3% RH from10 ~ 90% RH
    • ±5% RH for other ranges
  • RH resolution: 0.1 % RH
  • Response time: approximately 15 seconds
  • Operating ranges: 32° to 122°F (0° to 50°C)
  • Operating humidity range: 0~95% RH
  • Storage temperature range: -4° to 149°F (-20° to 65°C)
  • Storage humidity range: 0 to 95% RH
  • Alarm level: approximately 70dB
  • WBGT Alarm setting range: 68° to 99°F (20° to 37.2°C)
  • Power: 2 AAA batteries (included)
  • Battery life: typically 250 hours (can be as much as 1000 hours without alarm condition)
  • Black ball size: 1.6" diameter (40mm)
  • Meter size: 1.2" (D) x 1.9" (W) x 9.8" (L)


  • 33% Calibration standard. Relative Humidity Reference HR33LJ
  • 75% Calibration standard. Relative Humidity Reference HR75LJ
  • Windows® Logging Software & RS-232 cable ASFT-KIT

Download Users Manual (PDF format)

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What our customers say...

Sirs: Thanks for the quick delivery. The heat stress meters showed up just in time. The calibrations were Spot-On. Thanks again. Do you have a case or carrier for these?

Rated by Martin J
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