💡 5 Key Takeaways
- A 5-gas detector simultaneously measures the 5 gases legally required for confined space work in Korea: O₂, CO, H₂S, CO₂, and LEL.
- Since the 2017 OSH Act amendment, CO₂ was added to the previous 4-gas standard, making 5-gas mandatory.
- A 3-year data retention requirement makes IoT cloud functionality practically essential.
- IECEx + ATEX dual certification is needed for hazardous areas.
- WANDI's EDW500 covers all requirements: 5-gas measurement, dual explosion-proof certification, and automatic email reporting for 3-year retention compliance.
What Is a 5-Gas Detector?
A 5-gas detector is a portable multi-gas instrument that simultaneously detects five gases mandated by Korea's Occupational Safety and Health Act for confined space work: O₂, CO, H₂S, CO₂, and LEL (flammable gases).
The 5 Required Gases
- O₂ (Oxygen) — Asphyxiation risk; safe range 18% to 23.5%
- CO (Carbon Monoxide) — Poisoning risk; below 30 ppm
- H₂S (Hydrogen Sulfide) — Lethal at high concentrations; below 10 ppm
- CO₂ (Carbon Dioxide) — Asphyxiation risk; below 1.5%
- LEL (Flammable Gas) — Fire/explosion risk; below 10% LEL
Why 5 Gases? The 2017 Korean OSH Act Amendment
Until 2017, only 4 gases (O₂, CO, H₂S, LEL) were required. The 2017 amendment added CO₂ after repeated accidents in septic tanks, wastewater facilities, and fermentation sites where CO₂ buildup caused asphyxiation.
2024 Additional Amendment: Equipment Provision and Data Retention Now Mandatory
- Gas measurement equipment provision is mandatory
- Measurement records must be retained for 3 years
- Enhanced worker training requirements
- Safety monitors must report to 119 in emergencies
7 Criteria for Choosing a 5-Gas Detector
- All 5 gases included (O₂, CO, H₂S, CO₂, LEL)
- Dual explosion-proof certification (IECEx + ATEX)
- Diffusion vs. pump-type — pump required for pre-entry measurement
- IoT/cloud functionality for 3-year data retention
- Real-time alarms to PC/smartphone
- KOLAS calibration certificate or in-house calibration authority
- A/S infrastructure with local parts inventory
4-Gas vs 5-Gas Detectors
| Type | Gases | Legal Status (Korea) |
|---|---|---|
| 4-Gas | O₂·CO·H₂S·LEL | Non-compliant since 2017 |
| 5-Gas | O₂·CO·H₂S·LEL + CO₂ | Current legal standard |
- 4-Gas: O₂·CO·H₂S·LEL — no longer meets Korean legal requirements since 2017
- 5-Gas: O₂·CO·H₂S·LEL + CO₂ — current legal standard
Recommended 5-Gas Detector: EDW500
- ✅ 5-gas simultaneous measurement: O₂·CO·H₂S·CO₂·LEL
- ✅ Dual international explosion-proof: IECEx TPS 25.0057X + ATEX TPS 25 ATEX 114935 0006 X Rev. 01
- ✅ Usable in all hazardous zones (0, 1, 2) — Ex da ia IIC T4 Ga
- ✅ Pump-type (EP500) option for pre-entry measurement
- ✅ Free DCMS cloud + built-in NB-IoT — zero subscription fees
- ✅ Auto email reporting → automatically meets 3-year retention requirement
- ✅ Real-time PC/smartphone alarms
- ✅ In-house calibration + 5-business-day A/S
🏆 EDW500 — 5-Gas Compliance + 3-Year Retention in One Device
Korea's rare IECEx+ATEX dual-certified + DCMS auto-email reporting
Post-Purchase: Calibration and A/S
- Recommended calibration cycle: every 6–12 months
- Sensor replacement: EC 2–3 years, catalytic 3–5 years
- Choose suppliers with in-house calibration authority for faster turnaround
📚 Related Guides
📖 Confined Space Safe Work Procedures
Revised OSH Act requirements
📖 Explosion-Proof Certification Guide
IECEx · ATEX · Zone 0
📖 Korean OSH 5-Gas Mandatory Measurement
2024 legal amendments
📖 5-Gas Detector TOP 5 Comparison
Price & certification comparison
Closing — A 5-Gas Detector Is Not Optional
Since the 2017 amendment, a 5-gas detector is a legal requirement for confined space work in Korea. The 2024 additional amendment requires equipment provision and 3-year data retention. Modern 5-gas detectors must include explosion-proof certification, IoT auto-storage, and rapid A/S.
📞 Free EDW500 5-Gas Detector Consultation
Tell us your site conditions — we'll recommend the optimal EDW500 configuration.
📷 EDW500 5-Gas Detector Product Photo Gallery
See real photos and key features of the WANDI EDW500 portable 5-gas detector.
