Environmental Monitoring Equipment & Supplies • Sales, Rental & Service by Enviro-Equipment — Charlotte, North Carolina USA

Casella Microtherm 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.

This item is no longer available for rent.

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.

Items Included:
  • 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

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.


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.