Modeled: (2) heat detectors, 8" below ceiling, 8" apart, with and without 12" deep beam centered between them.
Results without-- Both near and far side heads activate at 90.5 seconds. Margin of error a few tenths of a second. Results with-- near side=93.8 seconds. far side=115.0 seconds. Same margin of error. Head scratching -- 1) I doubt in real life two heads 8" apart would activate within tenths of a second of each other, my feel is more like a few, enough for one to cold-solder the other. 2) in a model the spray pattern of a sidewall can be straight out, but in real life I think enough would be splashed backward to cause 1). For 30 years, if I thought beyond what the book said about max deflector distance I thought "ok, the heat rises, hits the bottom of the deck, and starts coming down, and when this heat gets, say, 12" down the head pops". Well, 10 years ago I realized that that is normal-- and the emergency is where the heated air is travelling horizontally five to ten feet per second across the head. 10 years ago is also when I first heard "ceiling jet". I really resented a Code Person telling me anything about sprinklers but, after 3 months of getting my sprinkler (oops i mean head) around mass and the metric system learning the first things about FDS, it started sinking in that the ceiling jet is really where is at re: activation. Brad C Ps- this new thread is tied to the recent "can sidewalls..." thread. Ps2- Ron, I'm not too sick, tired (or lazy), to look stuff up-- i just don't have access to commentary, and I was curious, but it can wait. Ps3- Ron2-----please don't be a stranger _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
