Burning Rate and Flame Heat Flux for PMMA in the Cone Calorimeter.
Burning Rate and Flame Heat Flux for PMMA in the Cone
Rhodes, B. T.
NIST GCR 95-664; Thesis; 125 p. December 1994.
Sponsor:National Institute of Standards and Technology,
Order number: PB95-216990
cone calorimeters; burning rate; heat flux; polymethyl
methacrylate; ignition; experiments; mass loss; heating;
thermoplastics; small scale fire tests
Ignition and burning rate data are developed for thick
(25 mm.) black Polycast PMMA in a Cone Calorimeter
heating assembly. The objective is to establish a
testing protocol that will lead to the prediction of
ignition and burning rate from Cone data. This is done
for a thermoplastic like PMMA. For black PMMA, ignition
temperatures of 250 to 350 deg C and vaporization
temperatures of approximately 325 to 380 deg C were
measured over irradiance levels of 15 to 65 kW/m(2).
The incident flame heat flux, for irradiation levels of
0 to 75 kW/m(2), is found to be approximately 37 kW/m(2)
for black PMMA. Its constancy is shown due to the
geometry of the Cone flame. Also, this flame is shown
to be nearly transparent for Cone irradiance (>90%).
The heat of gasification of the black PMMA used is found
to be approximately 2.8 kJ/g; higher than other values
reported for PMMA. This is believed to be due to
differences in molecular structure or pigmentation
effects and the types of PMMA tested. A burning rate
model is demonstrated to yield good accuracy (>80%) in
comparison to measured transient values.