Freon Gas Alarm (Refrigerant Leak Alarm)

for detection R22、R134a、R410A、R404A、R32 Refrigerant leaks,Prevent suffocation and poisoning in enclosed spaces,R32 etc. also pose explosion risks, widely used in refrigeration rooms, cold storage, central air conditioning rooms, cold chain workshops, in compliance with theGB500722021 Cold Storage Design Standard" mandatory requirement by China Academy of Building...。

1. System composition

1. Detector (probe): installed at leak points, collects gas concentration, explosion-proof type for on-site machine rooms.
2. Alarm controller host: placed in duty room, real-time concentration display, audible and visual alarm, relay can be linkedExhaust fan, compressor shutdown, solenoid valve。
3. Signal output:420mA、RS485, can be connected toPLC/DCS; some with IoT remote upload.

2. Sensor principle comparison

Table

Sensors	Advantages	Disadvantages	Applicable scenarios
NDIR infrared (recommended for industrial)	Long lifespan, resistant to water vapor interference, good selectivity, unaffected by oxygen	Higher price	Cold storage, refrigeration rooms,R134a/R410A/R32 and most other refrigerants
Semiconductor	Low price, fast response	Susceptible to alcohol, oil contamination, large drift	Simple leak detection, portable
Catalytic combustion	Specifically for detecting flammable refrigerants (R32、R290）	Requires oxygen, cannot detect inert refrigerants	Flammable refrigerant conditions

✅ Industrial refrigeration rooms prioritizeInfrared principle detector, good stability, convenient for annual inspection and calibration.

3. Installation points (national standard GB/T504932019、GB500722021）

1. Most Freon (R134a/R410A/R22) heavier than air: probe installedAbove the ground 0.30.6m, sensor facing downward, arranged at low points under compressors, valves, flanges, pipes, with emphasis on trench locations. China Academy of Building...。
2. R32 Lighter than air: probe installedUnder ceiling 0.30.6m High places, gas accumulates upward.
3. Maximum protection radius per detector≤7.5m; avoid direct fan airflow, water vapor, oil fume, strong electromagnetic interference, reserve space for calibration and maintenance.
4. Controller wall-mounting height 1.41.6m, placed in areas with personnel on duty.
5. Alarm linkage: low alarm activates exhaust fan; high alarm activates exhaust + Shutdown, alarm signal transmitted to duty room.

4. Alarm threshold reference

Different refrigerant limits vary, based on the refrigerant used SDS and GBZ2.1-2019 as the standard

• R125：PCTWA=1000ppm, first-level alarm≤1000ppm, second-level≤2000ppm
• R134a No national occupational limit, common engineering: low alarm2001000ppm, high alarm30005000ppm
• R32 Flammable: set according to flammable gas, low alarm25% LEL, high alarm50% LEL

5. Key selection parameters & qualifications

1. Confirm the refrigerant model to be detected,R32 Must also consider flammable detection.
2. Explosion-proof: select for hazardous areas in machine roomsEx d IIC T6 Gb; protection level≥IP65(cold storage humid condensation environment).
3. Required certificates: explosion-proof certificate,CMC Measurement certificate; engineering acceptance projects also requireCPA Type approval certificate.
4. Range: common 01000ppm、05000ppm, flammable refrigerants0100% LEL。
5. Distinguish:Fixed (long-term online monitoring) / Portable (inspection leak detection)