OLCT IR Fixed Gas Detector

Rugged and Reliable Infrared Transmitter Detector for Intrinsically Safe Applications.

Offshore platforms, petrochemical and chemical industries, naval installations, waste water treatment plants… in these types of environments, infrared technology is very often the only solution. The OLCT IR is built to withstand these harsh environments, which require the most efficient gas and flame detection.
Proven Leading-Edge Technology
  • “Zero Maintenance” Efficiency
  • The answer to false alarms
  • Non-intrusive calibration
Two Configurations for Adapting to Your Site
  • Standalone Version
  • Free-Fitting Version
Unrivalled Performance
  • Reliability
  • Durability
Special Version
  • The semi-conductor electronics of the OLCT IR guarantee extreme accuracy and constant stability.
  • Costs are considerably reduced:- Lifetime detector stability after initial calibration- Requires minimal maintenance
  • The economic implications of false alarms have led us to design the OLCT IR with the ability to ignore external elements that trigger false alarms.  
  • Equipped with a non-intrusive system allowing a single operator to access a protected menu.
  • The detector can therefore be calibrated in an explosive area in total compliance with safety rules.  
  • Includes a case fitted with a mounting system and a wiring compartment for electrical connections in explosive zones.
  • Magnetic system for calibrating in explosive zones without opening the compartment cover.  
  • Includes a case fitted with a 3-wire output for connection to any approved junction box.  
  • Highly resistant to sensor poisoning
  • High gas concentration does not saturate the transmitted signal
  • All vital functions are maintained even if an accumulation of dust or other substances reduces transmission by 70%.
  • Heated mirror and window to prevent misting or icing of the optics
  • Operates in an oxygen deficient atmosphere  
  • Stainless steel explosion-proof compartment, secure connection compartment
  • The mirror is made of quartz
  • External optics are made of quartz capable of withstanding high pressure and abrasive substances.
  • Simultaneously optimises the response to various hydrocarbons, meeting the requirements for multi-hazard sites.
For more information on the OLCT IR Fixed Gas Detector, contact your local Air-Met office. 
  • 4-20 mA analogue infrared transmitter
  • SIL2 capability
  • Infrared CO2 or combustible gas detector
  • IP67
  • Double source / four beams
  • Heated optics
  • Dirty optics compensation
  • Low maintenance
  • Resistant to poisons
  • Long lifespan (>10 years)
  • Non-intrusive calibration
Detection Principle
Optics: infrared absorption
Detected Gases
  • Hydrocarbons 
  • Methane, propane/butane as standard
  • Others on request including CO2
  • 0-100% LEL CH4, C3H8, C4H10
  • 0-100% of volume CH4
  • 0-3% of volume CO2
Housing IP66/IP67, DIN40050
Ingress Protection 316L Stainless Steel

1% LEL

  • +/-3% LEL CH4 or +/- 5% of the value
  • +/-2% LEL HC or +/- 3% of the value
Response Time T90 < 8 sec.
Self Test Continuous
Calibration In factory or locally
Humidity Range 0 to 99% (without condensation)
Output Signal 4-20 mA
Max Load Resistance
300 Ω
Trouble Signals
  • Line fault (0 mA)
  • Optics fault (0.5 mA)
  • Other fault (1 mA)
  • Calibration mode (2 mA)
  • Scale over range (23 mA)
Power Supply 15 to 30 VDC at detector terminal
Average Consumption 2.5 W
Connection 3 active wires, shielded cable
Maximum Resistance Per Conductor Of Detector/Central Unit Cable 8 Ω (250 m in 1.5 mm2) under 21 VCC
Type Of Cable Inlet M20, Cable gland not supplied
Operating Temperature
  • -25°C to +55°C on standard version
  • -50°C to +55°C on CH4 version
  • (P/N WIRCH4LBT) & Propane
Storage Temperature - 50°C to 55°C
Weight And Dimensions 212 x 105 x 120 mm; 1.6 kg
EC Electromagnetic Compatibility Complies with EN50270
Certifications Ex
Ineris 03ATEX0141X
Ex d e ia IIC T4- II 2GD
Ex tD A21 IP66 T135C
T.amb: -50°C to +65°C
IECEx INE 07.0005X
Ex d e ia IIC T4- II 2GD
Ex tD A21 IP66 T135C
T.amb: -50°C to +65°C
EN 61779-1, -4
SIL Capability
SIL capability 2
EN 50402/EN 61508
  • Offshore platforms
  • Petrochemical and chemical industrial gas monitoring
  • Naval installation
  • Waste water treatment plant gas detection
  • Food and beverage gas detection/monitoring
  • Workplace health and safety