Effect of an Obstructed Ceiling on the Activation Time of a Residential Sprinkler.
Effect of an Obstructed Ceiling on the Activation Time
of a Residential Sprinkler.
Vettori, R. L.
NISTIR 6253; 150 p. November 1998.
Sponsor:General Services Administration, Washington, DC
Available from: National Technical Information Service
Order number: PB99-100042
sprinklers; residential sprinklers; sprinkler response;
sprinkler systems; beams; ceiling jets; corners; fire
growth; tenability limits; wall fires; sprinkler
A series of 45 experiments were conducted to compare the
effects of two different ceiling configurations on the
activation times of a quick response residential pendent
sprinkler. The two ceiling configurations consisted of
a smooth horizontal unobstructed ceiling and a
horizontal ceiling obstructed by parallel beams
measuring 0.038 m (1.5 in) wide by 0.24 m (9.5 in) deep
and spaced 0.41 m (16 in) on center. For each of the
two ceiling configurations, the fire source, a computer
controlled methane gas burner, was placed in three
different locations within the fire compartment and 2.1
m (7 ft) below the ceiling. Additionally, for each
burner location, the flow of methane gas to the burner
was supplied in such a way as to give three different
fire growth scenarios. For the smooth horizontal
unobstructed ceiling three experiments were performed
for every burner position and fire growth rate. For the
horizontal obstructed/beamed ceiling there were two
experiments for everyburner position and fire growth
rate. Measurements taken include the time to sprinkler
activation, temperature and velocity of the ceiling jet
at the sprinkler of activation, and temperatures and
ceiling jet velocities at various other locations and
elevations within the fire compartment. The horizontal
obstructed/beamed ceiling increased sprinkler activation
time by 57% to 137% depending on the experimental setup.