Thanks Rahe. Just to try to clarify, 13 shows sidewalls with a wall, or soffit, and soffits normally protrude from a wall. Apparently some manufacturer's data says they can be used with a wall or beam, but I doubt what was envisioned was "back-to-back" sidewalls with a beam between them, which would be required by 13 and the data, but likely a beam say, 8" from a "real wall", and only on the interior side, to better look like the pictures in 13. And please note, the activation times I showed really don't mean much-- I used a space of X by Y by Z, open on the end opposite the fire, with a certain heat release and fire growth rate. Changing any of those would change the activation times. The interesting thing is difference with and without the beam, and that is what I meant by the margin of error being tenths of a second. In other words, I don't try to predict anything, I like keeping all things the same but one, say deflector distance, and seeing what the difference is, according to the model that is :)
Brad On Dec 31, 2015 12:06 PM, "Rahe Loftin - 7PMC" <[email protected]> wrote: > I got it. I was thinking that you had sidewalls 8 inches apart back to > back and another set 8 feet from them. Very interesting test. It is > always interesting to find things in NFPA 13 that mysteriously do not work, > as indicated, in real life. > > > > *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 1:04 PM, Brad Casterline <[email protected]> > wrote: > > > Rhae, > > No, 8" apart is correct. This is a continuation of the ~do sidewalls > need a > > wall discussion~ but I made it new because I don't know how to trim > threads > > using my phone. > > Very interesting stuff. > > When looking at activation only I use a heat detector because the same > RTI > > algorithm is used for upright, pendent, sidewall, and heat detector. > > It is interesting to note that the 12" deep beam affects the near sprk > like > > an 18" draftstop affects a water curtain sprk-- it disrupts the heat > flow, > > delaying activation a few seconds. I think an 18" draft stop is used to > > contain an 18" "build down" of 'cold smoke', per floor, when openings are > > required to be protected. > > On Dec 30, 2015 12:30 PM, "Rahe Loftin - 7PMC" <[email protected]> > > wrote: > > > > > 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 > > > > > _______________________________________________ > > 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 > _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
