- Author
-
Wighus, R.
- Title
- Extinguishment of Enclosed Gas Fires With Water Spray.
- Coporate
- SINTEF NBL-Norwegian Fire Research Lab., Trondheim, Norway
- Book or Conf
- International Association for Fire Safety Science. Fire Safety Science. Proceedings. 3rd International Symposium. July 8-12, 1991,
Elsevier Applied Science, New York,
Edinburgh, Scotland,
Cox, G.; Langford, B., Editors,
997-1006 p.,
1991
- Keywords
-
fire research
|
fire safety
|
fire science
|
water sprays
|
extinguishment
|
enclosures
|
spray nozzles
|
droplet size
|
experiments
|
propane
|
ventilation
|
heat balance
|
heat transfer
- Identifiers
- Spray Heat Absorption Ratio (SHAR)
- Abstract
- Experiments were performed in a 2.5 x 2.5 x 5 (m3) enclosure with various water spray nozzles fighting a 1 MW propane fire. Ventilation was provided through an inlet opening at floor level, and an outlet opening at ceiling level. Fire induced ventilation was examined. The fire source was propane forming an equivalent pool fire with dimensions 0.3 x 1.3 m2. The nozzles produced sprays with a full cone coverage, with mean nominal water droplet diameter varying from about 0.5 mm to 1.6 mm. The results are presented as a heat balance for the water spray, the compartment and the ventilation smoke, by a ratio SHAR - Spray Heat Absorption Ratio. A general observation is that the fire was extinguished when the spray received a certain fraction of the heat release rate. The extinction mechanisms seem to be a combination of inerting the combustion zone with evaporated water, and a consequent reduction of temperature. When the water spray received only a lesser fraction of the release heat, the total heat flux to the compartment is considerably reduced. There is a distinct connection between water droplet size and the ability to extinguish the fire, in favor of the smallest droplets.