- Author
-
Cooper, L. Y.
- Title
- Interaction of an Isolated Sprinkler Spray and a Two-Layer Compartment Fire Environment. Phenomena and Model Simulations.
- Coporate
- National Institute of Standards and Technology, Gaithersburg, MD
- Journal
-
Fire Safety Journal,
Vol. 25,
No. 2,
89-107,
September 1995
- Sponsor
- American Architectural Manufacturers Assoc., Des Plaines, IL
- Keywords
-
sprinklers
|
sprays
|
compartment fires
|
smoke layers
|
fire models
|
mathematical models
|
nozzles
|
sprinkler systems
|
ceiling vents
|
critical temperature
|
smoke filling
- Identifiers
- qualitative description of spray/layer interactions; sprinkler-spray/lower-layer interaction; model inputs: the fire environment and the sprinklers characteristics; simulated interactions between two-layer fire environments and a Rockwood T-4 spray nozzle flow; summary of the example calculations - ceiling venting to enhance the effectiveness of sprinkler systems; using the sprinkler/layer interaction model in LAVENT
- Abstract
- A general description of the interaction of sprinklers and compartment-fire-generated smoke layers is presented. Various possible aspects of the interaction phenomena (upper-layer smoke entrainment into the sprinkler spray, momentum and mass exchange between droplets and entrained gas, gas cooling by evaporation, buoyancy effects, and others) are discussed in the context of a two-layer-type description of the fire environment. The inputs and outputs for a mathematical submodel which simulates the phenomena are discussed. The submodel is suitable for general use in any two-layer, zone-type compartment fire model. Results from exercising the submodel are presented. These example calculations simulate the interaction between the spray of a real sprinkler device and a range of two-layer fire environments. The calculations revealed an important generic interaction phenomenon, namely, an abrupt and large change in the growth rate of an upper layer that would accompany an increase in upper layer thickness beyond a critical thickness (for a given upper layer temperature) or an increase in upper layer temperature beyond a critical temperature (for a given upper layer thickness). Exceeding these critical values would lead to very large rate of growth of upper layer thickness, a growth that could lead to rapid and complete smoke filling of even the largest compartments of fire origin.