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Ceiling Jet Flows.

pdf icon Ceiling Jet Flows. (802 K)
Evans, D. D.

NFPA SFPE 95; LC Card Number 95-68247;

SFPE Handbook of Fire Protection Engineering. 2nd Edition. Section 2. Chapter 4, National Fire Protection Assoc., Quincy, MA, DiNenno, P. J.; Beyler, C. L.; Custer, R. L. P.; Walton, W. D., Editor(s), 2/32-39 p., 1995.


fire protection; fire protection engineering; ceiling jets; fire growth; high temperature gases


Much of the hardware associated with detection and suppression of fires in commercial, manufacturing, storage, and recently constructed residential buildings is located near the ceiling surfaces. In the event of a fire, hot gases in the fire plume rise directly above the burning fuel and impinge on the ceiling. The ceiling surface causes the flow to turn and move horizontally under the ceiling to other areas of the building remote from the fire position. The response of smoke detectors, heat detectors, and sprinklers installed below the ceiling so as to be submerged in this hot flow of combustion products from a fire provides the basis for the building fire protection. Studies quantifying the flow of hot gases under a ceiling resulting from the impingement of a fire plume have been conducted since the 1950s. Early studies at the Fire Research Station in Great Britain, and more recently at Factory Mutual Research Corporation, the National Institute of Standards and Technology (NIST), and at other research laboratories, have sought to quantify the gas temperatures and velocities in the hottest portion of the flow produced by steady fires beneath smooth, unconfined horizontal ceilings.