Measuring thermal conductivity

Researchers at the US National Institute of Standards and Technology (NIST) have developed a technique for measuring a key thermal property of fire-resistive materials at high temperatures.

The measurement technique has already been adopted commercially and incorporated into a US standard.

In creating computer simulations to study the collapses of the World Trade Center buildings on 11 September 2001, NIST researchers needed to know important properties of the fireproofing materials that protected the structural steel columns.

One key property was the thermal conductivity of the material.

There are long-established methods for measuring thermal conductivity under ambient conditions, but a material's thermal conductivity can change markedly when it is subjected to extremely high temperatures that cause important chemical and structural changes.

Traditional methods for measuring thermal conductivity at high temperatures have not been adequate.

NIST's Dale Bentz and his colleagues Robert Zarr and Daniel Flynn developed a so-called 'slug calorimeter' technique to obtain the thermal conductivity information at elevated temperatures.