Stopwatch, Heat Index
Extech HW30 Heat Index Stopwatch
Portable environmental safety monitoring combined with precise timekeeping for occupational health management.
The Extech HW30 is a specialized, dual-purpose industrial diagnostic tool designed for site safety officers, field supervisors, and occupational health managers. More than just a standard precision timer, this device continuously monitors ambient temperature and relative humidity to calculate and display the Heat Index—a critical metric for assessing the risk of heat stress during strenuous physical activity or labor in high-temperature environments.
Engineered for immediate field response, the HW30 allows safety personnel to actively time work-rest cycles while simultaneously ensuring environmental conditions remain within safe operational thresholds.
Key Technical Capabilities
Active Heat Index Monitoring: Automatically calculates the heat index based on temperature and humidity, providing an accurate representation of how hot it feels to personnel on site.
Programmable Safety Alarms: Features a user-adjustable heat index alarm that emits an audible warning when conditions exceed safe predefined limits, enabling proactive safety interventions.
Advanced Chronometer Functions: Functions as a highly accurate stopwatch with a 100-lap memory, split time tracking, and a calendar/clock mode for comprehensive event and shift timing.
Simultaneous Display: The easy-to-read LCD screen continuously displays the current temperature, humidity, and heat index alongside the active timer.
Field-Ready Design: Built with a lightweight, ergonomic housing and an included lanyard, making it easy to wear or carry during active facility inspections or field operations.
Technical Specifications Summary
| Parameter | Measurement Range | Basic Accuracy |
| Heat Index | 22°C to 50°C (70°F to 122°F) | ±3°C (±5.4°F) |
| Temperature | -10°C to 50°C (14°F to 122°F) | ±1.3°C (±2.4°F) |
| Relative Humidity | 1% to 99% RH | ±5% RH |
| Stopwatch Capacity | 9 hours, 59 minutes, 59 seconds | 1/100th second resolution |
Integrate proactive heat stress management into your daily operational timing