Prediction Based Design of Fire Detection for Buildings With Ceiling Heights Between 9 m and 18 m.
Prediction Based Design of Fire Detection for Buildings
With Ceiling Heights Between 9 m and 18 m.
Davis, W. D.; Notarianni, K. A.
NISTIR 6199; 47 p. July 1998.
Sponsor:National Aeronautics and Space Administration,
Available from: National Technical Information Service
Order number: PB98-148158
ceiling jets; draft curtains; experiments; fire models;
heat detectors; high bay; pool fires; smoke detectors;
The analysis of hangar experiments (NIST TN 1423) with
15 m and 22 m ceiling heights has led to a better
understanding of the evolution of a fire driven ceiling
jet. This work has demonstrated the impact of the
presence of a hot upper layer on the radial and vertical
temperature profiles of the ceiling jet. The importance
of using a fire size dependent radiative fraction is
established which, when used in conjunction with models
which account for the entrainment of upper layer gas
into the plume, provides better predictive capabilities
for the plume centerline temperature. Plume and ceiling
jet algorithms, which model the observations, have been
developed and embedded in a new zone fire model. The
analysis of detector response using these experiments
has resulted in the ability to establish threshold fire
sizes for using smoke and heat detectors. It has also
led to the recommendation of a lower temperature
threshold to be used in computer models to determine
smoke detector activation. Guidelines for spacing of
smoke and heat detectors are discussed. The importance
of a draft curtains at these heights is established, and
the impact of the draft curtains on detector spacing is