BS01 specifications:
Heat flux measurement 3 separate heat flux sensors
Temperature measurement 4 type K thermocouples
Flexibility 30 mm minimum radius
Sensitivity (nominal) 50 μV/Wm-2
Expected accuracy (to 50°C) within 2.5 %
Temperature coefficient of the calibration coefficient – 0.17 %/°C
Temperature range 0-100 °C
Pressure range 1-110 bar
Cover dimensions 140 x 360 mm

Click for enlargement

Figure 2 BS01 dimensions.
1 to 3 individual heat flux sensors (1, 2, 3)
T1 to T4 temperature sensors
Cabling (4)
Wiring code:
1 to 6 heat flux sensor wiring
7 to 14 temperature sensor wiring
dimensions in mm.

The BS01 is a large-area flexible heat flux and temperature sensor for in-situ evaluation of the insulation value of pipes. With years of experience put into the design, it is the standard for pipe insulation testing for subsea oil pipes.

A nice clear print of the original product brochure.


The BS01 contains three heat flux sensing areas and four integrated temperature sensors. Originally designed for "simulated service conditions testing" for subsea oil pipelines, it can withstand high hydrostatic pressures up to 110 bar and is (contrary to other sensors) completely water-tight. The main development effort has gone into the prevention of penetration of moisture into the sensor at high pressures. With sensors not specifically prepared for the high pressure, penetrated moisture will on the long term lead to instability of the sensor calibration.
The sensor is provided with a mounting set for easy fixation, consisting of a cover and two springs.
BS01 was originally designed by TNO TPD. Scientific publication about this sensor: D. Haldane (Heriot Watt University), F. van der Graaf, A.M. Lankhorst (TNO TPD): A direct Measurement System to obtain the Thermal Conductivity of Pipeline Insulation Coating Systems under Simulated Service Conditions.

Figure 1 BS01 on pipe during in service testing.
3 Cabling
4 Pipeline to be tested
5 BS01 mounted on pipeline (cover and springs for fixation are not shown)

Suggested Use

  • General pipeline insulation testing
  • Simulated service testing for subsea pipelines


  • Alternative designs: Hukseflux is specialised in heat flux sensor design, and can offer sensors with modified dimensions and specifications.
Version 0617