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Investigation of the Fire Environment in the ASTM E 84 Tunnel Test. Final Report.


pdf icon Investigation of the Fire Environment in the ASTM E 84 Tunnel Test. Final Report. (60098 K)
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

Keywords:

ASTM E84; fire tests; flame spread; heat flux; heat release rate; smoke; asbestos cement board; tunnel tests; oxygen concentration

Abstract:

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.