Specimen Heat Fluxes for Bench-Scale Heat Release Rate Testing.
Specimen Heat Fluxes for Bench-Scale Heat Release Rate
Interscience Communications Ltd.; National Institute of
Standards and Technology; Building Research
Establishment; and Society of Fire Protection Engineers.
Interflam 1993. (Interflam '93). Fire Safety.
International Fire Conference, 6th. March 30-April 1,
1993, Oxford, England, Interscience Communications Ltd.,
London, England, Franks, C. A., Editor(s), 57-74 pp,
Fire and Materials, Vol. 19, No. 6, 243-252, 1995.
fire safety; fire science; cone calorimeters; heat
release rate; heat flux; radiant heating; corner tests;
room fires; upholstered furniture; wall fires
When a specimen is tested for its heat release rate
(HRR) behavior using a bench-scale test such as ISO 5660
or equivalent, one very important test condition is not
pre-standardized and must be set: the heat flux to be
imposed on the specimen by the heater. The heat flux
cannot be legitimately standardized, since the value
appropriately to be used will differ according to
purpose or application. The present paper sets forth
the considerations which should govern the correct
choice of heat flux. A discussion is given of minimum
ignitability level; statistical variability at low heat
fluxes; the ranges of heat fluxes associated with small
actual ignition sources; the heat fluxes associated with
fires away from the ignition source, all the way up to
fully-involved room fires; the applicaton of the
product; and the needs associated with mathematical
modeling of room fires. Correlational approaches are
also illustrated and contrasted to physics-based ones.
Finally, the empirical nature of the present situation
is emphasized. Judged from first principles, it would
appear that successful prediction of room fire results
from bench-scale test data would require both the
testing at a large number of different heat fluxes and
the use of algorithms to permit time-dependent
interpolation. Such algorithms have been proposed;
however, some very successful predictions are noted with
much simpler techniques.