Investigation of the Fire Environment in the ASTM E 84 Tunnel Test. Final Report.
Investigation of the Fire Environment in the ASTM E 84
Tunnel Test. Final Report.
Parker, W. J.
NBS TN 945; CIB W14/77/18 (USA); 75 p. August 1977.
Available from: National Technical Information Service
Order number: PB-270722
ASTM E84; fire tests; flame spread; heat flux; heat
release rate; smoke; asbestos cement board; tunnel
tests; oxygen concentration
Measurements were made of heat flux, oxygen
concentration, temperature, velocity and pressure in a
series of instrumented ASTM E 84 tunnel tests using (1)
standard length specimens, (2) 0.91-m (3-ft) long
specimens, and (3) a reference specimen consisting of
asbestos-cement board and an auxiliary controlled supply
of methane. Five different flow rates of methane to the
auxiliary burner provided constant and known heat inputs
simulating the gaseous decomposition products from
regular test specimens. Incident heat fluxes on an inert
specimen surface as high as 6.3 W/cm(2) (5.5
Btu/ft(2).s) were measured within the flame impingement
zone with a water-cooled heat flux meter 0.61 m (2 ft)
downstream from the burner. While oxygen depletion in
the tunnel did not appear to be a dominating factor in
controlling the flame spread, the oxygen depletion
measured in the exhaust duct beyond the tunnel
correlated with the total rate of heat production of the
specimens. It appears that the differences in the
observed burning behavior of materials in the tunnel
test and in a room may be mainly due to differences in
the incident heat flux distribution in the two cases.
These distributions reflect the different geometries,
orientations, and ignition sources. The potential for
rapid flame spread of some low flame spread
classification (FSC) low density materials is evident
from observations of the flame propagation along these
materials during the tunnel test, but is not adequately
reflected in the flame spread classification.