Thermal Performance of Fire Resistive Materials I. Characterization With Respect to Thermal Performance Models | NIST

Fire resistive materials (FRMs) are currently qualified and certified based on lab-scale fire tests such as those described in the ASTM E119 Standard Test Methods for Fire Tests of Building Construction and Materials [1]. While these tests provide an “hourly” rating for the FRM, these ratings have no direct quantitative relationship to the performance of an FRM in an actual fire, e.g., a 2 h rating does not mean that the FRM will protect the steel (or other substrate) for 2 h in a real world fire. Computational heat transfer models offer the potential to bridge the gap between laboratory testing and field performance. However, these models, whether basic one-dimensional or more complex three-dimensional versions, depend critically on having accurate values for the thermophysical properties of the FRM (and substrate) as a function of temperature, to be used as inputs along with the system geometry and fire and heat transfer boundary conditions. Properties required include density, heat capacity, thermal conductivity, and enthalpies of reactions and phase changes. In this report, procedures for determining a consistent set of these input values are presented. Then, quantitative data for a variety of FRMs and several steel substrates that have been obtained from the literature or measured in the Building and Fire Research Laboratory are presented. The utilization of these properties to successfully simulate the thermal response of an FRM-steel layered system is demonstrated for the National Institute of Standards and Technology slug calorimeter experimental setup. Ultimately, similar performance simulations will be executed for E119-type tests and even real fires.