Dual Gas Infrared Sensors

The SGX infrared sensors use the proven Non-Dispersive Infrared (NDIR) principle to detect and monitor the presence of gases. With an infrared source and specific filtering on the pyroelectric detectors mounted inside the optical/gas cavity, individual gases or types of gas can be identified and their concentrations determined. These sensors are suitable for reliable monitoring of gas levels in general safety applications where the sensor size is restricted and require a flameproof enclosure for hazardous environments.

The IR15 Series contain two active detector elements for simultaneous monitoring of Carbon Dioxide and Methane or Hydrocarbon mixtures in the same size housing as some of the single gas sensors from the IR1xxx series sensors, making the sensor more cost effective than two separate sensors.

Features of the Dual Gas infrared Sensors

  • For detection of Carbon Dioxide & Hydrocarbons or Hydrocarbons Mixtures
  • Gas concentration ranges:   0 – 5% Carbon Dioxide (also suitable for 0 to 0.5%v/v);   0 – 100% Carbon Dioxide (also suitable for 0 to 10%);   0 – 100%v/v Hydrocarbons (also suitable for 0 to 100%LEL)
  • 19mm sensor height
  • Embedded thermistor for improved temperature compensation
  • Diffused gas sampling via mesh
  • Low power
  • Reference channel for self-compensation
  • Special gold plated optical gas cavity for stable signal levels
  • Operational in varying temperature, pressure and humidity
  • Fast response
  • Rugged stainless steel construction
  • No moving parts
  • Immunity from ‘poisoning’
  • Reliable fail-safe operation
  • Certified: ATEX, IECEx, CSA and UL


The IR15TT can be used in all applications for general monitoring of both relatively low concentrations of carbon dioxide and simultaneous %LEL and %v/v concentrations of Group II hydrocarbons, including benzene. The sensors contain a broadband hydrocarbon detector which are cross sensitive to most hydrocarbons and can therefore be calibrated to a specific target gas or a number of gases that can then be selected in the configuration of the customer’s gas measurement instrument.


The IR15TT-M is very similar to the IR15TT except that a narrowband hydrocarbon detector is used. The sensor can still be used to monitor the same levels of carbon dioxide and hydrocarbons but are unsuitable for the detection of benzene. The narrowband detector also has a slightly lower response to humidity than the IR15TT, but is generally more cross-sensitive to other hydrocarbons.


The IR15TT-R was designed specifically for Biogas applications for the simultaneous detection of carbon dioxide up to 100%v/v and %LEL and %v/v concentrations of hydrocarbons, but can be potentially used for other applications. The IR15TT-R contains the narrowband detector which is unsuitable for the detection of benzene.


The IR15TT-D is fitted with both the narrowband and broadband hydrocarbon detectors with differing centre wavelength and bandwidth to potentially differentiate between hydrocarbons. The sensor was designed for the gas instruments being used by utilities companies to help differentiate between different compositions of natural gas.


Part NumberDescriptionDatasheet
IR15TTDual Gas infrared sensorDownload
IR15TT-MDual Gas infrared sensorDownload
IR15TT-RInfrared gas sensor for Biogas applicationsDownload