Study of the Chemical and Physical Mechanisms of Fire Suppression by Water.
Study of the Chemical and Physical Mechanisms of Fire
Suppression by Water.
Atreya, A.; Crompton, T.; Suh, J.
Fire Safety Science. Proceedings. Sixth (6th)
International Symposium. International Association for
Fire Safety Science (IAFSS). July 5-9, 1999, Poitiers,
France, Intl. Assoc. for Fire Safety Science, Boston,
MA, Curtat, M., Editor(s), 493-504 pp, 2000.
Sponsor:National Institute of Standards and Technology,
fire research; fire safety; fire science; water; fire
suppression; diffusion flames; flame temperature; flame
radiation; experiments; water vapor
This work attempts to develop a quantitative
understanding of the chemical and physical gas-phase
fire suppression mechanisms of water. Small-scale
diffusion flame experiments and calculations with
detailed kinetics are done to study these gas-phase
effects. The experimental results show that there is a
significant chemical enhancement effect due to increased
water vapor concentration in the flame zone. This effect
reduces the soot concentration and oxidizes CO to CO2.
Consequently. the combustion becomes more complete and
the flame temperature is increased as the water
concentration is increased. The actual magnitude of the
chemical enhancement. however, depends on the water
concentration the 02 concentration and the flame
temperature. Mixing caused by liquid water application
and water evaporation may significantly affect the gas
composition. In particular, it may increase the CO
concentration for a low 02 concentration fire
environment. It was also found that an increase in the
water vapor concentration considerably enhances the
radiative heat loss from the flame. This heat loss
becomes less significant with increase in the strain
rate due to a reduction in the flame zone thickness.