Casella Microtherm WBGT Heat Stress Monitor Rental

  • Designed to monitor heatstress potential of personnel in hot working environments for ISO 7243/7726 and OSHA standards.
  • Simultaneously measures Wet Bulb, Dry Bulb and Globe Temperatures.
  • Processed data includes WBGT (indoor and outdoor), 1 Hour (TWA) WBGT values, %RH and Dewpoint.
  • Software included for data download and generating reports and graphs.
  • Field calibrator and annual factory calibration certificate included.


We no longer offer this product.

If available, alternative products will be listed below.

The Casella Microtherm is a Wet Bulb Globe Thermometer that measures WBGT Index for workers who are exposed to hot working environments. The instrument combines results from 3 different temperature sensors into a single calculated value that can be compared to a reference value based on the specific work regime.

The Microtherm features a large LCD screen with real time display of changing levels. The instrument datalogs, has audible and visual alarms when alarm levels are exceded, RH% calculation, and dewpoint calculation. It is compatible with Windows PC software to download and setup results from memory. Automatic calculation of work and rest regimes with included PC software.

For extended surveys, it includes a tripod mount, standard accessories in a customized case and calibration certificate. Meets the requirements of ISO 7243.

Sensing technique Platinum Resistance Temperature Detectors, 100 Ω elements to EN 60751 Class A using 4-wire cable up to 30 m
Ta, Dry Bulb (Air)
  • Measuring Range: 10 - 60°C
  • Accuracy: ±0.5°C
Tg, Globe
  • Measuring Range: 20 - 120°C
  • Accuracy 20 - 50°C: ±0.5°C
  • Accuracy 50 - 120°C: ±1.0°C
Tnw, Natural Wet
  • Measuring Range: 5 - 40°C
  • Accuracy: ±0.5°C
Relative Humidity Less than ±5% from 35 - 100% RH
  • 0.1o for temperature
  • 0.1% for RH
For inside/outside measurements with no solar load Use WBGTin = 0.7Tnw + 0.3Ta.
For outside measurements with solar load Use WBGTout = 0.7Tnw + 0.2Tg + 0.1Ta.
Instrument Consumption Approx. 30 mA.
Battery 4 x AA / MN1500 cells Alkaline or rechargeable Nickel Cadmium
Typical operating time Alkaline Batteries (2700 mAh), > 85 hours, Rechargeable NiCd cells (950 mAh), > 30 hours
Battery Charging Internal NiCd fast charger circuitry. Charge termination based on Negative delta V detection with additional time-out protection. The charger must be disabled for dry cell operation
Charge Rate Fast charge rate 450 mA, Standby charge rate 55 mA approx.
Power adapter Universal with input voltage range 100 - 240 V AC, 47 - 63 Hz. Output 12 V DC at 0.8 A. Supplied with connectors for UK, USA and European mains outlet sockets. The instrument may be powered continuously from the external power adapter.
  • Casella Microtherm Heat Stress Monitor
  • WIN HSM Software
  • Distilled Water Bottle
  • Operators Manual
  • Carrying Case
  • Spare Batteries
  • RS232 Data Cable
  • Spare Wicks
  • Factory Calibration Certificate