Field Modeling: Simulating the Effect of Sloped Beamed Ceilings on Detector and Sprinkler Response. International Fire Detection Research Project. Technical Report. Year 2.
Field Modeling: Simulating the Effect of Sloped Beamed
Ceilings on Detector and Sprinkler Response.
International Fire Detection Research Project.
Technical Report. Year 2.
Davis, W. D.; Forney, G. P.; Bukowski, R. W.
Technical Report; Year 2; 41 p. October 1994.
Sponsor:National Fire Protection Research Foundation, Quincy, MA
Available from: National Fire Protection Research
Foundation (NFPRF), 1 Batterymarch Park, Quincy, MA
fire detection; field models; ceilings; fire detectors;
detector response; sprinkler response; conservation;
equations; heat transfer; smoke detectors; joists
The rapid activation of fire detection and suppression
systems in response to a growing fire is one of the
important factors required to provide for life safety
and property protection. Rapid activation requires that
sensors be located at optimal distances both beneath the
ceiling and radially from the fire. Ceiling
obstructions, such as beams and joists, and ceiling
slope can significantly modify the flow of smoke along
the ceiling and must be taken into consideration when a
particular detection system is designed. At present,
the standards used to guide the design of these systems
contain very little quantitative information concerning
the impact of beamed, sloped ceilings on sensor
placement. A multiyear, International Fire Detection
Research Project sponsored by the National Fire
Protection Research Foundation (NFPRF) was initiated to
provide quantitative information on the impact of beams,
ceiling slope, and forced ventilation on the movement of
smoke in commercial/industrial properties. During the
first year of the project, numerical modeling was
validated and additional simulations of level, beamed
ceilings for detection of growing fires at design fire
sizes of 100 kW and 1 MW were completed. It was found
that conditions under beams may be equivalent in some
cases to conditions in the channels between the beams at
an equivalent height beneath the beam or ceiling
respectively. Also, depending on detectable fire size,
beam depth and beam spacing, smoke detectors or quick
response fusible links may not be necessary for each
beam channel. This report describes the results of the
second year of the project. During the second year,
numerical simulations of smoke movement in response to
sloped, beamed ceilings were studied. Slopes of 10, 25
and 50 degrees were studied with beams running along or
across the slope. It was found that channeling of smoke
flow was more prevalent as ceiling slope increased for
parallel beam cases. For beams perpendicular to the
slope, increasing the ceiling slope decreased the
effectiveness of the beams in preventing smoke flow up
the ceiling. Based on the predicted smoke movement,
recommendations on sensor selection and placement are
made for sloped, beamed ceilings.