- Author
-
Evans, D. D.
- Title
- Thermal Actuation of Extinguishing Systems.
- Coporate
- National Bureau of Standards, Gaithersburg, MD
- Journal
-
Combustion Science and Technology,
Vol. 40,
79-92,
1984
- Report
-
NBSIR 83-2807,
March 1984,
28 p.
- Distribution
- Available from National Technical Information Service
- Book or Conf
- National Bureau of Standards/Center for Fire Research. Fire Science for Fire Safety. August 23-25, 1983,
Gaithersburg, MD,
Levine, R. S.; Pagni, P. J., Editors,
1984
- Keywords
-
fire models
|
fire plumes
|
fire protection
|
heat detectors
|
sprinkler systems
|
zone models
- Abstract
- A brief review of the Response Time Index (RTI) method of characterizing the thermal response of commercial sprinklers and heat detectors is presented. Measured ceiling layer flow temperature and velocity histories from a bedroom fire test are used to illustrate the use of RTI in calculating sprinkler operation times. In small enclosure fires, a quiescent warm gas layer confined by the the room walls may accumulate below the ceiling before sprinkler operation. The effects of this warm gas layer on the fire plume and ceiling-jet flows are accounted for by substitution of an equivalent point source fire. Relationships are given for the locating and strength of the substitute source relative to a point source representation of the actual fire. Encouraging agreement was found between measured ceiling-jet temperatures from steady fires in a laboratory scale cylindrical enclosure put into dimensionless form based on parameters of the substitute fire source, and existing empirical correlations from fire tests in large enclosures in which a quiescent warm upper gas layer does not accumulate.