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