Brad, Should your post say 8' apart instead of 8"?
*Success Through Code Compliance* *Rahe Loftin, PE * *Regional Fire Protection Engineer* *General Services Administration* *Region 7 - TX, OK, NM, AR, LA* *Facilities Management & Support 7PMC* *c - 817-371-3102* *o - 817-978-7299* On Wed, Dec 30, 2015 at 11:07 AM, Brad Casterline <[email protected]> wrote: > 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 > _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
