💡 3 Key Takeaways
- EC, Pellistor, and PID sensors have completely different operating principles with distinct strengths and weaknesses.
- Choosing the wrong sensor type for your environment can make accurate measurement impossible.
- In complex gas environments, expert field analysis and sensor recommendation is essential.
① EC Sensor (Electrochemical Sensor)
Measures electric current generated when gas reacts at electrodes in an electrolyte solution. The standard method for toxic gas detection (CO, H₂S, O₂, NO₂, SO₂, NH₃, Cl₂, etc.).
Best for: Wastewater plants (H₂S, O₂), boiler rooms/parking garages (CO), confined space pre-entry checks, plating/semiconductor facilities (Cl₂, NH₃, HF).
Avoid when: H₂S + SO₂ co-exist (negative cross-sensitivity), temperatures above 60°C (electrolyte evaporation), below −20°C (electrolyte freezing), high alcohol environments (false CO alarms).
② Pellistor Sensor (Catalytic Bead)
Detects combustible gas by measuring resistance changes caused by heat generated when gas combusts on a platinum bead surface. The industry standard for LEL measurement.
Best for: LNG/LPG storage facilities, general chemical plants (no poisoning risk), petrol stations, tunnels/underground parking.
Avoid when: Silicone coating/waterproofing work (catalyst poisoning → permanent sensitivity loss), paint/coating operations, oxygen-deficient environments (below 10% O₂), chlorinated solvent environments.
③ PID Sensor (Photo-Ionization Detector)
Ionizes gas molecules with UV light and measures the resulting ion current. Specialized for VOC (volatile organic compound) detection at ppb levels.
Best for: Semiconductor/display factories, paint/coating workplaces (BTX VOCs), environmental contamination surveys, petrochemical plant leak detection.
Avoid when: High humidity (>90% RH), measuring CH₄/CO/H₂ (cannot ionize), heavy oil mist/dust environments, single-compound quantitative analysis of mixed VOCs.
3-Sensor Comparison
| Item | EC | Pellistor | PID |
|---|---|---|---|
| Target Gas | Toxic gases | Combustible (LEL) | VOCs |
| Sensitivity | ppm | % LEL | ppb~ppm |
| Cost | Low | Low | High |
| O₂ Required | Some | Yes (>10%) | No |
| Poisoning Risk | Low | High (critical) | UV lamp fouling |
Expert Consultation: WANDI Korea
Real industrial environments are never simple. Wastewater plants produce H₂S (EC needed) and CH₄ (Pellistor needed) simultaneously. Paint shops combine VOCs (PID needed) with combustible gas risk (Pellistor poisoning risk). When conditions are complex, expert field analysis is essential before selecting a sensor type.
WANDI Korea (wandi.co.kr) carries all sensor types — EC, Pellistor, PID, and IR — and provides 1-on-1 recommendations based on your specific field environment.
📞 Free Sensor Selection Consultation
Tell us about your gas environment and we'll analyze which sensor type — EC, Pellistor, or PID — is right for you.
wandi.co.kr | TEL: 031-340-6952