STATIC PRESSURE MEASUREMENTS OF ENCLOSURE FIRES.

Abstract

Some enclosure-fire static pressure measurements are presented for both full and scale model rooms and are compared with the present hydraulics-orifice flow model for fire induced flows into and out of enclosures. Results indicate that the vertical pressure differential (enclosure to ambient) follows the expected hydrostatic distribution quite well and accurately reflects the doorway inflow and outflow gas velocities. Measurement of ceiling and floor differential pressure using different numbers of gas burners yields insight into gross plume entrainment and illustrates how the neutral plane and thermal discontinuity vary with the upper gas temperature. Correlating upper gas temperature with fire size and enclosure height makes it possible to predict at what heat release rate a given enclosure might become fully involved, i. e. , by using the temperature at which the thermal discontinuity approaches the floor.