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Versatile measurement platform with accurate methods for thermal conductivity, thermal diffusivity, specific heat and thermal effusivity of solids, liquids, pastes and powders.

TPS Sensor

– ISO 22007-2, GB/T 32064
– Solids, pastes, powders

MTPS Sensor
MTPS (optional)

– ISO 22007-7
– Solids, pastes, powders

THW Sensor

– ASTM D7896
– Liquids

TLS Sensor
TLS (optional)

– ASTM D5334-22a, D5930, IEEE-442
– Soil, polymers

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Transient methods share similar theory with differences that are specific to their primary design.

The sensors are electrically connected to a power supply and sensing circuit. A current passes through the sensors and creates an increase in temperature, which is recorded over time. The heat generated is then diffused into the sample at a rate dependent on the thermal transport characteristics of the material.


Intelligent transient design for automation of testing and analysis. Raw data is always available to empower understanding of your results. Name your sample, iTransient does the rest.

itransient process

  • Transient Plane Source
  • Transient Hot Wire
  • Modified Transient Plane Source
  • Transient Line Source
Absolute Methods

The mid-range MP-V includes two primary test methods for thermal conductivity, thermal diffusivity, specific heat and thermal effusivity. Conforming to international standards, the transient plane source (TPS) and transient hot wire (THW) are designed specifically for their primary applications. As MP-V methods are absolute, the thermophysical results are calculated from the raw-data, with no need for contact agents or calibration.

TPS Sensor
Transient Plane Source Sensor (TPS, ISO 22007-2, ISO 22007-7 / GB/T 32064)

The TPS (double spiral) sensor is placed between two pieces of the same sample. As the sample acts as a semi-infinite body, thermophysical properties are measured over a range of optional test times (2 to 160 seconds), which are auto-determined by the iTPS algorithm. The range of available sensor diameters allows sample size flexibility. Additional testing modules available include anisotropic, thin-films and specific heat.

  • Solids, pastes and powders
Transient Hot Wire Sensor (THW, ASTM D7896)
Transient Hot Wire Sensor (THW, ASTM D7896-19)

The THW sensor is inserted into the liquid sample cell. The small diameter sensor wire and short test time are designed to reduce effects of convection. The THW method is well-published for testing liquids with accurate and reliable results.

  • Liquids
Optional Absolute Methods
Modified Transient Plane Source Sensor (MTPS, Absolute)
Modified Transient Plane Source Sensor (MTPS, ISO 22007-7)

The MTPS sensor follows the same principles of operation as TPS. The sensor is configured for asymmetric (single-sided) testing, ideal when only one piece of sample is available. Included testing modules are bulk, anisotropic, slab and 1-D for full characterization of diverse materials.

  • Solids, pastes and powders
Transient Line Source Sensor (TLS, ASTM D5334-22a, D5930, IEEE-442)
Transient Line Source Sensor (TLS, ASTM D5334-22a, D5930, IEEE-442)

The TLS sensor consists of a thin heating wire and temperature sensor sealed in a steel tube. The sensor is completely inserted into the sample to be tested.

  • Soil and polymers
Transient Hot Wire Sensor (THW, ASTM D7896-19)

The THW-L sensor is specifically designed for use with temperature and pressure for testing liquids past their boiling points. The test cell can be back pressured (up to 20 bar) to keep liquid in stable state.

  • Liquids and PCMs
TPS Modules

Bulk thermal conductivity, thermal diffusivity, specific heat and thermal effusivity. Symmetric and asymmetric.

Anisotropic 3 Dimensional Module

Anisotropic In-plane and out-of-plane thermal conductivity and thermal diffusivity. Symmetric and Asymmetric.

Slab 3 Dimensional Module

Isolated in-plane for thermal conductivity, thermal diffusivity and volumetric specific of sheets. Symmetric only.

Thin Film 3-Dimensional Module

Thermal conductivity of thin-films and coatings according to ISO 22007-2.

General - Specific Heat
Specific Heat

High accuracy direct measurement of specific heat. Various cell dimensions available for improved accuracy of heterogenous materials.

Standard 1-Dimensional module

Isolated out-of-plane for thermal conductivity, thermal diffusivity for elongated shapes, rods and bars. Asymmetric only.

* Modified Transient Plane Source (MTPS) only

Specifications Comparison Chart
Materials Solids, pastes and powders Liquids Solids, pastes and powders Soil and polymers Liquids and PCMs
Thermal conductivity (W/m·K) 0.01 to 100 / 500 0.01 to 2 0.03 to 100 / 500 0.1 to 8 0.01 to 2
Thermal diffusivity (mm²/s) 0.01 to 50 / 300 Up to 0.5 0.01 to 50 / 300 N/A Up to 0.5
Specific heat (J/kg-K) Up to 5 Up to 5 Up to 5 N/A Up to 5
Thermal effusivity (W√s/m²K) 20 to 20000 / 40000 N/A 20 to 20000 / 40000 N/A N/A
Temperature (°C)* Room temperature or -75 to 300 Room temperature or -50 to 100 -50 to 200 -40 to 100 0 to 100
Accuracy 5% 2% 5% 5% 2%
Repeatability 1 to 2% 1% 2% 2% 1%
Smallest dimension** 10mm x 10mm to unlimited 20 ml 25mm x 25mm to unlimited 50mm to unlimited 20 ml
Sample thickness (mm)** 0.05 to unlimited N/A 0.1 to unlimited 100 to unlimited N/A
Standard ISO 22007-2:2022,
ISO 22007-7:2023,
GB/T 32064-2015
ASTM D7896-19 ISO 22007-7:2023 ASTM D5334-22a,
ASTM D5930-17,
IEEE 442-2017
ASTM D7896-19

*For temperature, external control required.
** Based on testing module used.


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