|Proposed Thermal Measurements Test Method to Determine Effective Thermal Conductivity
A need for a new test method to determine the effective thermal conductivity of fire resistive materials at high temperatures has prompted ASTM International Committee E37 on Thermal Measurements to begin work on a proposed new standard, WK12643, Test Method for Slug Calorimetry. The proposed standard is under the jurisdiction of Subcommittee E37.05 on Thermophysical Properties.
Assembled slug calorimeter specimen ready for testing in the furnace. The coating shown is an organic intumescent material, surrounded by a high temperature microsilica thermal insulation, with the assembly being held together by two retaining plates.
According to Dale Bentz, chemical engineer, Building and Fire Research Laboratory, National Institute of Standards and Technology, the materials that would be tested in accordance with WK12643 are used to protect structural steel during fire exposure. In doing so, these materials undergo multiple reactions and significant dimensional changes during exposure to high temperatures, “For example,” says Bentz, “some intumescent fire resistive coatings may expand their thickness by up to 40 times during a fire exposure.”
WK12643 will be used to evaluate the effective thermal conductivity of fire resistive materials and other temperature insulations from room temperature to about 750 ºC. “By performing multiple heating/cooling cycles during the testing, valuable information on the influence of chemical reactions, phase changes and the transport of generated steam and hot gases through the materials can be obtained,” says Bentz.
The proposed standard will primarily be useful to fire resistive material manufacturers and thermal measurement testing laboratories, but Bentz notes that it may ultimately find usage in application to a wide variety of materials.While participation in Subcommittee E37.05 is welcome at any time, the subcommittee is especially interested in finding laboratories to aid in the implementation of an interlaboratory round robin to establish a precision statement for WK12643. In addition, the subcommittee is seeking participants for developing a set of reference materials for high temperature measurements. //
Technical Information: Dale Bentz,
Building and Fire Research Laboratory, National Institute of Standards and Technology, Gaithersburg, Md.
ASTM Staff: Thomas O’Toole
March 19, 2007
ASTM International Headquarters
West Conshohocken, Pa.