A lump-capacitance heat transfer model was developed to model the operation of a slug calorimeter constructed of metal with a Curie point. The resulting formula has been successfully used to infer total heat flux to a metal structural member in a fire by temporally monitoring the internal temperature rise during the heat-up phase of the metal member (slug) with embedded thermocouples. The formula derived is applicable to slug calorimeters made from metals with or without a Curie point.
and Ohlemiller, T.
Analysis of a Slug Calorimeter with a Curie Point, Technical Note (NIST TN), National Institute of Standards and Technology, Gaithersburg, MD, [online], https://doi.org/10.6028/NIST.TN.2090
(Accessed May 6, 2021)