Phosphine (PH₃) is an extremely toxic colorless gas generated during grain fumigation, semiconductor doping, and metal phosphide handling. With a Korean OEL of 0.3 ppm TWA, it causes serious damage to the heart, lungs, liver, and kidneys. The WANDI EDW500 with IECEx international explosion-proof certification (IECEx TPS 25.0057X) simultaneously measures 5 gases including PH₃, protecting workers entering fumigated spaces and semiconductor fab environments.
💡 Key Summary
The PH₃ exposure limit is 0.3 ppm TWA — extremely low. The odor threshold (~1 ppm) is 3× above the exposure limit, meaning you may already be overexposed before smelling it. EDW500 detects PH₃ down to 0.01 ppm with a dedicated EC sensor. IECEx Zone 0 certified.
Phosphine (PH₃) Properties and Hazards
| Property | Value |
|---|---|
| Chemical Formula | PH₃ (MW: 34.0) |
| Explosive Range | 1.8% ~ 98% (in air) |
| Korea OEL (TWA) | 0.3 ppm |
| STEL | 1 ppm (15 minutes) |
| IDLH (NIOSH) | 50 ppm |
| Odor Threshold | ~1 ppm (rotten fish/garlic odor) |
PH₃ Health Effects by Concentration
| Concentration | Duration | Health Effect |
|---|---|---|
| 0.3 ppm (OEL) | Long-term | Chronic damage to heart, lungs, liver, kidneys |
| 1–5 ppm | Several hours | Headache, fatigue, nausea, chest pain |
| 50 ppm | Immediately | Loss of consciousness, death (IDLH) |
Sources: NIOSH Pocket Guide, Korea MOL OEL Notice, WHO Air Quality Guidelines
WANDI EDW500: Optimal PH₃ Detection Solution
EDW500 features a dedicated high-sensitivity EC sensor for PH₃ with 0.01 ppm resolution, enabling detection well below the exposure limit. IECEx Zone 0 certification ensures safe use even where phosphine poses explosion risk (semiconductor fabs, fumigation areas). Simultaneous 5-gas measurement covers PH₃, flammable gases (EX/LEL), O₂, CO, and H₂S in one portable unit.
PH₃ Prevention Scenario with EDW500
- 1After fumigation, ventilation begins: Worker holds EDW500 and measures at door gap before opening.
- 2Entry only when PH₃ below 0.15 ppm: Real-time display guides safe entry decision.
- 3Wear EDW500 inside: If PH₃ exceeds 0.3 ppm during work, immediate alarm → evacuate for additional ventilation.
- 4Simultaneous O₂ monitoring: 5-gas simultaneous detection covers both PH₃ and oxygen deficiency risks.
A Closer Look at the WANDI EDW500
Below are real photos of the WANDI EDW500 portable multi-gas detector and its use on site.
