Questemp 44 Cloud Monitoring: Real-Time WBGT Heat Stress Data for South African Mining
The Questemp 44 is the field standard for area heat stress monitoring. When connected to Ecostat’s cloud platform, it becomes a real-time compliance tool. As a result, it streams WBGT data around the clock, alerts safety officers the moment limits are approached, and builds the audit trail your operation needs under the Mine Health and Safety Act.
Heat Stress in Mining: Why WBGT Monitoring Has Changed
Heat stress is one of the most underreported occupational hazards in South African mining. Underground operations, in particular, face temperatures that trigger dangerous physiological responses. Moreover, the consequences of a heat-related incident extend beyond immediate human harm. They also carry Mine Health and Safety Act liability for the operation.
The Wet Bulb Globe Temperature (WBGT) index is the internationally recognised metric for assessing heat stress. It accounts for temperature, humidity, radiant heat, and air movement. Together, these are the factors that determine thermal load on a worker’s body. For example, a WBGT of 28°C feels very different to a dry 35°C. Regulations reflect this distinction.
Under ISO 7243:2017, WBGT is the prescribed method for evaluating heat stress in occupational settings. South Africa’s Mine Health and Safety Act (MHSA) requires operations to manage heat exposure. In addition, the tightening of Regulation 6053 in 2025 halved the crystalline silica OEL. This signals a broader regulatory direction: limits are getting tighter, not looser. Consequently, heat stress enforcement will follow the same trajectory.
However, traditional heat stress monitoring has a fundamental problem. Manual WBGT readings taken once a shift miss the peaks. A reading at 08:00 does not capture what happens at 11:30. Surface temperatures can spike, or underground workings heat up from rock temperature or equipment exhaust. As a result, workers may face dangerous WBGT levels for hours before anyone knows.
Cloud-connected continuous monitoring closes that gap entirely.
The Questemp 44: Technical Specifications
The TSI QUESTemp° 44 (QT-44) is a purpose-built area heat stress monitor. It is designed for demanding field environments. Unlike earlier WBGT monitors that required daily wet-wick maintenance, the QT-44 uses a waterless wet bulb sensor with a proprietary algorithm. This makes it practical for remote or underground deployment where daily upkeep is not feasible.
| Parameter | Questemp 44 Capability |
|---|---|
| Measurements | Dry bulb temperature, globe temperature, relative humidity, WBGT (indoor), WBGT (outdoor), Heat Index / HUMIDEX |
| Wet bulb method | Waterless — no daily wick maintenance required |
| Data logging intervals | 1, 2, 5, 10, 15, 30, or 60 minutes |
| Time/date stamping | Yes — on-board clock and calendar |
| Temperature display | Celsius or Fahrenheit |
| Ingress protection | IP54 — protected against dust, dirt, oil, and water |
| Standards compliance | ISO 7243 WBGT standard for occupational heat stress |
| Deployment | Area monitoring — tripod-mounted at worker height in any location |
The QT-44 withstands the physical demands of mining environments. This includes vibration, dust, humidity fluctuations, and temperature extremes. Furthermore, its IP54 rating means it can remain in place in most underground and surface locations without daily attention.
How Ecostat Connects the Questemp 44 to the Cloud
The QT-44 logs data internally. However, internal logging means someone must physically visit the instrument to retrieve it. That defeats the purpose of continuous monitoring. Ecostat’s integration closes this gap.
The integration architecture is straightforward:
- QT-44 at the monitoring point — logs WBGT, dry bulb, wet bulb, globe temperature, and relative humidity at configured intervals. Typically, this is every 5 or 15 minutes.
- Arduino or RS-232 interface controller — reads the instrument’s serial output and passes it to the modem.
- Teltonika RUT906 cellular modem — transmits data to the Ecostat cloud over 4G/LTE via an OpenVPN tunnel.
- Ecostat cloud database — receives, timestamps, and stores every WBGT reading with full metadata.
- Portal and mobile app — provides live WBGT dashboards, configurable threshold alerts, historical trend analysis, and scheduled compliance reports.
As a result, every WBGT reading from every Questemp 44 across your operation appears on a single dashboard in real time. Safety officers receive push notifications the moment WBGT approaches action limits. There are no site visits required. There is no data download and no gap in the record.
In practice, this is exactly how leading SA underground mining operations structure their heat stress monitoring on the Ecostat platform. They replace interval-based manual readings with uninterrupted cloud data streams.
WBGT Action Limits: What the Regulations Require
Understanding the regulatory framework behind WBGT monitoring helps explain why continuous data matters. In short, a manual reading every few hours is simply not sufficient.
ISO 7243:2017 is the international standard for heat stress assessment. It sets WBGT reference values by work intensity and acclimatisation status. For example, for moderate work with an acclimatised worker, the reference limit is approximately 28°C WBGT. For unacclimatised workers or heavy physical work, the limit drops to 25°C or lower.
South Africa’s Mine Health and Safety Act requires operations to:
- Assess heat exposure for all workers in thermally stressful environments
- Implement controls when WBGT exceeds action limits
- Keep records of heat exposure assessments
- Ensure workers are acclimatised before full exposure to hot environments
Importantly, the MHSA does not prescribe a single WBGT number. Instead, it requires a risk-based approach. This approach accounts for work rate, clothing, acclimatisation, and duration. Therefore, your monitoring data needs to be contextualised, not just collected. A cloud platform links WBGT data to work area, shift timing, and worker activity. This provides contextual intelligence that a standalone instrument cannot.
Beyond MHSA, the 2025 changes to Regulation 6053 reduced the silica OEL. This signals that the DFFE and DMRE are moving toward tighter occupational health standards across the board. Consequently, mining operations that build a culture of continuous monitoring now are better positioned for future regulatory changes.
From Manual Readings to Real-Time Cloud Data: The Operational Difference
Consider a typical underground mining scenario. A safety officer takes a WBGT reading at 07:00 at the start of shift. The reading is 25.5°C, within safe limits. However, by 10:30, rock temperature, equipment exhaust, and reduced airflow push the WBGT to 30°C. Workers are exposed for two hours before the next manual reading at 13:00.
With continuous cloud monitoring, the outcome is completely different. At 10:45, the Ecostat platform detects the WBGT crossing the configured alert threshold. An automated push notification reaches the safety officer’s phone within seconds. The section supervisor is contacted immediately. As a result, the area is evacuated or ventilation adjusted before sustained exposure occurs.
The difference is not incremental. It is categorical. One approach is reactive. The other is preventive.
Across 130+ sites and 250M+ data points, Ecostat’s platform has demonstrated this principle. It applies to every environmental parameter: PM10, PM2.5, SO₂, weather, and WBGT. In each case, continuous cloud connectivity transforms a measurement instrument into an active safety system.
Platform Features for Heat Stress Monitoring
When your Questemp 44 units connect to the Ecostat cloud, your environmental and safety teams get access to:
- Live WBGT dashboard — view all instruments across all sites at a glance. Colour-coded threshold status makes problem areas immediately visible.
- Configurable threshold alerts — set action levels and receive push notifications, SMS, or email the moment a limit is approached.
- Historical trend analysis — view WBGT patterns by shift, season, or work area. This helps identify which locations and times present the highest thermal risk.
- Automated compliance records — every reading is timestamped and stored in an auditable cloud database. Reports are formatted for MHSA compliance submissions.
- Multi-instrument view — group your Questemp 44 units by section, level, or shaft. Then see all readings on a single screen.
- REST API access — pull WBGT data directly into your internal EHS management system or ERP.
- Mobile app — available on iOS, Android, and Huawei AppGallery. Field supervisors check live WBGT from anywhere on site.
The Ecostat platform is instrument-agnostic. If your operation already has Questemp 44 units in the field, connecting them to the cloud does not require replacing any equipment. You simply add the cellular interface and onboard to the platform. Most sites stream live data within 48 hours of connection.
Explore our full monitoring solutions and learn how we serve mining and industrial operations across South Africa.
Connect Your Questemp 44 to the Cloud
Already have Questemp 44 units in the field? Most existing instruments can be connected without replacement. Book a 30-minute demo and we’ll show you exactly how the integration works.