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Enabling better global research outcomes in soil, plant & environmental monitoring.

FHF01 Foil heat flux sensor

FHF01 is a thin and flexible sensor for general-purpose heat flux measurement. FHF01 is very versatile: it has an integrated temperature sensor and a flexible sensor body fitting flat and curved surfaces. It is applicable over a temperature range from –40 to +150°C. FHF01 foil heat flux sensor measures heat flux from conduction, radiation and convection. It is often applied as part of a larger test- or measuring system.

  • flexible (bending radius ≥ 25 x 10-3 m)
  • low thermal resistance
  • wide temperature range
  • fast response time
  • large guard area
  • integrated type T thermocouple
  • robustness, including wiring with strain relief block
  • IP protection class: IP67 (essential for outdoor application)
Measurand heat flux
Measurand temperature
Temperature sensor type T thermocouple
Rated bending radius ≥ 25 x 10-3 m
Rated load on a single wire ≤ 1.6 kg
Sensing area 6.9 x 10-4 m2
Sensor thermal resistance 24 x 10-4 K/(W/m2)
Sensor resistance range 50 to 100 Ω
Sensor thickness 0.6 x 10-3 m
Uncertainty of calibration ± 5 % (k = 2)
Measurement range (-10 to +10) x 103 W/m2
Sensitivity (nominal) 4.5 x 10-6 V/(W/m2)
Operating temperature range -40 to +150°C
IP protection class IP67
Standard wire length 1.5 m

FHF01 measures heat flux through the object in which it is incorporated or on which it is mounted, in W/m2. The sensor in FHF01 is a thermopile. This thermopile measures the temperature difference across the flexible body of FHF01. A type T thermocouple is integrated as well. The thermopile and thermocouple are passive sensors; they do not require power.

Using FHF01 is easy. It can be connected directly to commonly used data logging systems. The heat flux in W/m2 is calculated by dividing the FHF01 output, a small voltage, by the sensitivity. The sensitivity is provided with FHF01 on its product certificate.

Robust and stable

Equipped with wires with strain relief, protective covers on both sides and potted so that moisture does not penetrate the connection block, FHF01 has proven to be very robust and stable.


FHF01 calibration is traceable to international standards. The factory calibration method follows the recommended practice of ASTM C1130 – 07.