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Thermal Performance of Fire Resistive Materials. Part 2. A Multi-Layer One-Dimensional Heat Transfer Model for Fire Resistive Materials Protecting a Substrate.


pdf icon Thermal Performance of Fire Resistive Materials. Part 2. A Multi-Layer One-Dimensional Heat Transfer Model for Fire Resistive Materials Protecting a Substrate. (327 K)
Prasad, K. R.; Bentz, D. P.

NISTIR 7482; 25 p. February 2008.

Keywords:

fire resistant materials; heat transfer; substrates; fire tests; ASTM E 119; building construction; building materials; experiments; furnaces; calorimeters; material proeprties; heating; cooling; mini-furnace; slug calorimeter; heating/cooling cycle; different furances

Abstract:

This report is the. second of a three-part series concerning the characterization and modelingof the thennal perfonnance of fire resistive materials (FRMs). These materials are currently qualified and certified based on lab-scale fire tests such as those described in the American Society for Testing and Materials (ASTM) El19 Standard Test Methods for Fire Tests of Building Construction and Materials. While these tests provide an "hourly" rating for the FRM, these ratings have no direct quantitative relationship to the performanceof 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 transfermodels 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 thennophysicalproperties 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. In part 1of this series, procedures for detennining a consistent set of these therrnophysical properties were presented. Now, in part 2, a computational one dimensional multi-layer model for the heat transfer from the fire, through the FRM, to the substrate is developed and. verified by comparison to the results of a series of slug calorimeter experiments, previously conducted in the Building and Fire Research Laboratory (BFRL). Ultimately, similar perfonnance simulations will be executed for ASTM E119 type tests and even real fires.