Advertisement

Fire Technology

, Volume 8, Issue 3, pp 181–195 | Cite as

Calculation of response time of ceiling-mounted fire detectors

  • R. L. Alpert
Article

Abstract

An understanding of the behavior of the fire plume and fire-induced flow near the ceiling of a room is necessary if one is to optimize detector response time and placement.

Keywords

Heat Transfer Rate Heat Release Rate Flame Spread Fire Technology Fire Detector 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Nomenclature

H

Ceiling height above burning fuel (ft)

h

Heat transfer coefficient (Btu ft−-2 min−-1 ° F−-1)

Q

Heat release rate (intensity) of fire (Btu min−-1)

Qmin

Smallest detectable heat release rate (Btu min−-1)

Fire Detectors

q

Heat transfer rate to detectors (Btu min−-1)

r

Radial distance from fire axis to detector (ft)

S

Detector spacing (ft)

T

Gas temperature (° F)

TL

Fixed temperature rating (° F)

t

Response time of detector

V

Gas velocity (ft sec−-1)

Y

Vertical distance from ceiling to sensing element of detector (ft)

Subscripts

max

Maximum value at any one radial position

o

Standard test condition

p

Fire plume

rm

Ambient condition

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Alpert, R. L., “Fire Induced Turbulent Ceiling-Jet,” FMRC Technical Report 19722-2,” Factory Mutual Research Corporation (1971).Google Scholar
  2. 2.
    Morton, R. B., Tayler, G. I., and Turner, J. S.,Proceedings of the Royal Society, Series A, No. 236 (1956), pp. 1–23.Google Scholar
  3. 3.
    Alpert, R. L., “The Ceiling-Jet Induced by Large-Scale Fires,” FMRC Technical Report 19722-4,” under preparation for 1972 Winter Annual Meeting of the American Society of Mechanical Engineers.Google Scholar
  4. 4.
    Rohsenow, W. M. and Choi, H.,Heat, Mass, and Momentum Transfer, Prentice-Hall, Englewood Cliffs, N. J. (1961), pp. 148, 200, 413.Google Scholar

Copyright information

© The National Fire Protection Association 1972

Authors and Affiliations

  • R. L. Alpert
    • 1
  1. 1.Factory Mutual Research CorporationUSA

Personalised recommendations