// Blog November 16, 2020

Thermal Conductivity of Thin Metal Sheets (Slab Utility)

Trident’s TPS Slab utility is recommended when the approximation of a “semi-infinite” sample size is no longer valid due to a restriction in the thickness of a sample. This effectively means when the thermal conductivity and thickness of the sample are such that the depth of penetration of the heat pulse will exceed the boundary condition of the sample itself. Samples must be classified as isotropic for the utility to function as intended.

Thermal Conductivity Testing of Aluminium

With the use of the utility, thin sample slabs, sheets or plates can be tested despite not meeting the TPS method’s general requirement for a semi-infinite sample behaviour. The size of the samples must be large enough that thermal boundary effects aren’t observed on the time scale of the test in the plane normal to the sensor surface, but thin enough to have boundary effects in the direction normal to the sensor surface which the Slab utility accounts for. The external slab surfaces must be adequately insulated against heat loss, or alternatively, the measurement can be conducted in a vacuum. As in the bulk mode, two identical samples are used.

Thermal Conductivity Testing Slab

Slab Thermal Conductivity Testing

Nominal Value[1]

ISO Acceptable Range[2]

Exp. Results


k (W/mK)

α (m2/s)

k (W/mK)

α (m2/s)

k (W/mK)

α (m2/s)




104 – 120

3.08 – 3.84E-05



In the example above in testing a brass slab sample, results fell approximately within 3.5% of the expected nominal value for thermal conductivity and are well within the tolerance outlined in ISO 22007-2

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[1] Nominal value was experimentally determined using an independent method.

[2] ISO 22007 specifies accuracy up to 7% k and 11% α when using the Slab Utility.


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