Probabilistic assessment of off-the-shelf fire sprinkler Head activation time through laboratory experiments

The performance of a sprinkler installed in an atrium roof was evaluated in this paper by considering three points: possibility of activating the sprinkler head, thermal response, and water requirement. Crude analysis us ing the empirical expressions of the fire plume and the zone model CFAST 2.0 were used to study the possibility of activating the sprinkler head. Smoke spreading out from a fire shop to the atrium was discussed. The software DETACT was used to calculate the activation time for the sprinkler heads of different response time indices installed at different ceiling heights under unsteady t-squared fires. Correlation expressions of the activation time with ceiling height, response time indices of the sprinkler head, fire growth coeffi cients, and ambient temperature were derived. The water requirement at the atrium floor was discussed by calculating the trajectories of water droplets. Higher flow rate and pressure are required for discharging the same water den sity at the floor level. Results indicated that installing an ordinary sprinkler system in a high headroom atrium would not be effective in controlling a fire.

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Discharge distribution performance for an axisymmetric model of a fire sprinkler head

Fire Safety Journal ◽

10.1016/0379-7112(88)90048-3 ◽

1988 ◽

Vol 14 (1-2) ◽

pp. 101-111 ◽

Cited By ~ 12

Author(s):

Joseph M. Prahl ◽

Bruce Wendt

Keyword(s):

Axisymmetric Model ◽

Sprinkler Head ◽

Discharge Distribution ◽

Fire Sprinkler

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Covering of cometary nucleus by refractory crust and its evolution into asteroid-like body

International Astronomical Union Colloquium ◽

10.1017/s0252921100031675 ◽

1999 ◽

Vol 173 ◽

pp. 365-370

Author(s):

Kh.I. Ibadinov

Keyword(s):

Laboratory Experiments ◽

Cometary Nucleus ◽

Sublimation Rate ◽

Cometary Nuclei ◽

Short Period Comet ◽

Short Period ◽

Brightness Decrease ◽

Crust Thickness ◽

Ice Sublimation ◽

Period Comet

AbstractFrom the established dependence of the brightness decrease of a short-period comet dependence on the perihelion distance of its orbit it follows that part of the surface of these cometary nuclei gradually covers by a refractory crust. The results of cometary nucleus simulation show that at constant insolation energy the crust thickness is proportional to the square root of the insolation time and the ice sublimation rate is inversely proportional to the crust thickness. From laboratory experiments resulted the thermal regime, the gas productivity of the nucleus, covering of the nucleus by the crust, and the tempo of evolution of a short-period comet into the asteroid-like body studied.

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When Does Voice Have to be More Than Only Listening? Procedural Justice Effects as a Function of Confident Leadership

Journal of Personnel Psychology ◽

10.1027/1866-5888/a000011 ◽

2010 ◽

Vol 9 (2) ◽

pp. 69-78 ◽

Cited By ~ 8

Author(s):

David De Cremer ◽

Maarten Wubben

Keyword(s):

Procedural Justice ◽

Interaction Effect ◽

Laboratory Experiments ◽

Negative Emotions

The present research examined how voice procedures and leader confidence affect participants’ negative emotions and willingness to withdraw. It was predicted that receiving voice would be valued out of instrumental concerns, but only when the enacting leader was high in confidence. Two laboratory experiments indeed showed an interaction between type of voice (pre-decisional vs. post-decisional) and leader’s confidence (low vs. high) on participants’ negative emotions and willingness to withdraw. In particular, post-decision voice only led to more negative responses than did pre-decision voice when the enacting leader was high in confidence. Negative emotions mediated this interaction effect of type of voice on willingness to withdraw. Implications for integrating the leadership and procedural justice literatures are discussed.

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