💡 3 Key Takeaways
- Korea's revised OSH Act (June 2025) mandates heat index measurement and record-keeping as a legal employer obligation.
- A standard thermometer is not enough. An instrument that automatically calculates apparent temperature from temperature + humidity is required.
- FIX800 offers 5-stage alerts, 95 dB alarm, and 180,000-record auto-storage — purpose-built for legal compliance.
Why Has Demand for Heat Index Monitors Surged?
Even in May, the heat already feels like summer — and just like last year, inquiries about heat index monitors are rising fast. Factories, outdoor job sites, logistics centers, and farms are all reaching out to prepare for heatwave season. The reason is clear: the revised OSH Act now mandates apparent-temperature-based worker protection measures, turning what were once voluntary guidelines into legal obligations.
📊 Heat Illness Industrial Accidents (Korea Workers' Compensation Corporation)
- Steady increase over the last 10 years
- As of October 2024: up 68% year-over-year (25 → 42 cases)
- Top sectors: construction, manufacturing, logistics, agriculture
What Is Apparent Temperature? — Why It Differs from Air Temperature
Apparent temperature represents what the human body actually feels, not just the air temperature. A standard thermometer only measures air temperature, but what workers experience also depends on humidity, wind, and surrounding conditions.
💡 Key Example
At the same air temperature of 32°C, a well-ventilated area with low humidity feels very different from a humid, poorly-ventilated enclosed workspace. High humidity prevents sweat from evaporating, making temperature regulation difficult and dramatically increasing the risk of heat illness.
In short, apparent temperature is not just about "how hot is it today" — it is the safety standard that determines how harsh the actual working conditions are for each worker. This is the core of the revised OSH Act.
OSH Act Amendment — What Changed?
Promulgated as Act No. 20522 on October 22, 2024 — effective June 1, 2025. Related ministerial rules mandatory from July 17, 2025.
Summary of Key Amendments
| Category | Requirement |
|---|---|
| Heat-Wave Definition | A meteorological condition with temperatures that can cause heat cramps, heat exhaustion, or heat stroke |
| Heat-Wave Work Definition | Long-duration work at a location where apparent temperature reaches 31°C or above |
| Measurement Height | Measured at approximately 1.2–1.5 m above floor level |
| Equipment Placement | Temperature/humidity monitoring device must be kept on-site at all times where heat-wave work is expected |
| Record-Keeping | Records of apparent temperature and measures must be retained until December 31 of that year |
| Rest at ≥33°C | At least 20 minutes of rest every 2 hours mandatory |
| Emergency Response | Immediate 119 call and appropriate action if heat illness is suspected |
| Other | Sufficient supply of salt and clean drinking water now explicitly required |
⚠️ Legal Risk Warning
These obligations are now legally mandated — no longer just voluntary guidelines. Non-compliance may result in criminal liability for employers under the Serious Accidents Punishment Act.
FIX800 Heat Index Monitor — Why It's Built for Compliance
We recommend the FIX800 Heat Index Monitor as the ideal solution for meeting the new regulatory requirements. FIX800 measures temperature and humidity, automatically converts them to apparent temperature, and instantly displays the alert level on-site.
✅ Point 1. Accurate Automatic Heat Index Display
📌 Standard: KOSHA (Korea Occupational Safety & Health Agency) heat index lookup table
🎯 Method: Apparent temperature automatically calculated from temperature + relative humidity
✅ Benefit: No manual calculation needed — instantly readable on the worksite
✅ Point 2. 5-Stage Alert System
| Stage | Apparent Temp. | Action Required |
|---|---|---|
| Normal | ≤30.9°C | Normal operations |
| Caution | 31–32.9°C | Heat-wave work — monitoring and logging mandatory |
| Warning | 33–34.9°C | Rest, cooling, or schedule adjustment required |
| Alert | 35–37.9°C | 20+ minutes rest per 2 hours mandatory |
| Danger | ≥38°C | Immediate work stoppage and heat illness response |
The display panels below show the 5-stage live alert screens under different temperature and humidity conditions.
✅ Point 3. 95 dB Alarm
📌 Feature: 95 dB alarm — audible even in loud industrial environments
🎯 Function: Light (strobe) + sound alert simultaneously / Alarm threshold and ON/OFF user-configurable
✅ Comparison: Standard hygrometers and competitor heat index monitors: only 6–70 dB
✅ Point 4. Auto Data Storage — The Key to Legal Compliance
📋 OSH Act Amendment — Article 562, Paragraph 4
When workers perform heat-wave work, apparent temperature readings and countermeasures must be recorded and retained until December 31 of that year.
💾 Storage Capacity: Up to 60,000 records per parameter (temperature, humidity, apparent temperature) — 180,000 records total
🎯 Benefit: No manual data entry — completely hands-free data management
✅ Compliance: Auto-stored data automatically satisfies the December 31 retention requirement
✅ Point 5. KOLAS Calibration Certificate
📌 Legal Basis: OSH Act Amendment Article 562(2) — recommends use of temperature/humidity devices calibrated by KOLAS-accredited laboratories
🎯 Feature: Unlike standard market hygrometers, FIX800 supports official calibration certificate issuance
✅ Benefit: Verified measurement reliability + readiness for regulatory inspections
📡 FIX800 + FIX-AP IoT Solution — Eliminate Manual Logging
When paired with the FIX-AP wireless hub, you can monitor all units remotely from the control room or office in real time, with automatic quarterly report emails — no separate data management required.
- Connect up to 16 heat index monitors per FIX-AP unit
- Web-based monitoring via on-site WiFi or LAN — no software installation required
- DCMS cloud service: completely free
- Automatic quarterly report emails — satisfies the December 31 data retention requirement automatically
📊 FIX800 vs. Competitors
| Feature | FIX800 | Standard Hygrometer | Other Heat Index Monitor |
|---|---|---|---|
| Temp/Humidity Measurement | ✅ | ✅ | ✅ |
| Apparent Temp. Conversion | ✅ | ❌ | ❌ |
| 5-Stage Alert Display | ✅ | ❌ | ❌ |
| Alarm Volume | 95 dB | 6–70 dB | 6–70 dB |
| High-Capacity Auto-Storage | ✅ (180,000 records) | ❌ | Partial |
| RS485 Output | ✅ | ❌ | ❌ |
| KOLAS Calibration Certificate | ✅ | ❌ | ❌ |
| Housing | Aluminum Alloy | Plastic (ABS) | Plastic (ABS) |
🏭 Recommended Environments
🏗️ Construction / Manufacturing / Logistics
Outdoor high-temperature work and enclosed warehouse/factory environments
🏢 Confined Workspaces
Spaces prone to heat and humidity buildup due to poor ventilation
🌾 Agriculture & Livestock
Greenhouses and livestock barns with high heat and humidity
🔥 Extreme Heat Environments
Smelting, steam-intensive, and other extreme industrial heat conditions
📞 FIX800 Inquiry & Consultation
We provide friendly guidance on OSH Act compliance and the optimal configuration for your site.
💬 Request Free Quote → 📋 View Cases →
wandi.co.kr | TEL: 031-340-6952