Furnace Exit-Gas Temperature (FEGT) Measurement System

Continuously measure Furnace Exit-Gas Temperature (FEGT) using Non-Contact Infrared Sensors to optimize overall performance of boilers and furnaces under varying conditions of coal quality, load, ash fouling, and slagging.

Furnace Exit-Gas Temperature (FEGT) Front View
FEGT System Schematic View

Key Features

  • Prevent failures by proactively monitoring the furnace temperature
  • Determine precisely when to perform sootblowing
  • Set trigger alarms to take quick corrective actions when gas temperatures approach slagging/fouling limits with continuous online monitoring
  • Measure and quantify trade-offs of heat rate and NOx and SO2 emissions
  • Optimize heat transfer by controlling FEGT under varying conditions
  • Prevent unwanted slag accumulation at inlet pendants by controlling FEGT below ash fusion temperatures
  • Reduce down time due to failures by prevention
  • Easily install and maintain while boiler is online.


In many combustion processes, one of the main combustion gases is CO2. Therefore, measuring the CO2 gas temperature is a reliable measurement of the combustion temperature.

Our combustion monitoring solution is a cost effective system that utilizes the IPE 140/45 pyrometer. This is a pyrometer specifically designed for reliable “non-contact” temperature measurement of hot combustion gas containing CO2.

The system is easy to install and maintain even while the boiler is online. It allows for a very quick reaction to undesirable conditions with continuous online monitoring of the combustion temperature.

LumaSense’s FEGT solution includes

  • Infrared Temperature Sensor
  • Protective Sealed Jacket Assembly
  • Protective Cooling Jacket
  • Vortex Air Cooler
  • Removable CaF2 Window Assembly (Window Slide)
  • Air Purge Assembly
  • Extended Site Tube
  • Mounting Flange (Ball Flange)
  • Air Filter for Vortex Air Cooler




  The FEGT system can be integrated directly into a plants control system or as part of a more complete solution as shown here. 

Technical Data


Infrared Thermometer 

Temperature Range

400 to 2000 ° C (MB 20) 

Spectral Range CO2 absorption band for hot CO2 gas
Uncertainty (Tamb. = 25 °C, ε=1, T90 =1s) Up to 1300 °C: 0.6% of reading in °C Above 1300 °C: 0.8% of reading in °C


0.1% of reading in °C + 1 °C


interface and display: 0.1 °C,

analog output:

< 0.03% of temperature range

Analog output  linear 0 to 20 mA or 4 to 20 mA, DC, switchable; load max. 500 Ohm
Power Supply

24 VAC/DC (14 to 30 VAC/DC)

(AC: 48 to 62 Hz)

Power Consumption 6 VA
Protective Housing

Stainless steel enclosure with vortex air cooling (air only required for long-term monitoring)

IP Rating (pyrometer) IP65 (DIN 40 050)
Note: The pyrometer is able to measure hot combustion gas (with typically approx. 10% CO2 ) with a thickness of 40 cm.
Max. Temperature Purge Air

75 °C (into cooler)

Max. ambient temperature enclosure

90 °C

FEGT System Weight approx. 6 kg

Air Filtering

5 µm filter

Ambient temperature 0 to 53 °C at pyrometer housing
Storage temperature -20 to 60 °C
Relative humidity Non condensing conditions
Vortex Cooler
Model 208-25-HSS
Material Stainless Steel
Inlet 1/4 inch
Cooling Capacity  440 Watts
Air Consumption @ 6.9 bar 708 slpm / male inlet

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