Everyone is WAY overthinking the purpose and the operation of a sidewall sprinkler on a building column. Put in a 5.6K sprinkler and be done with it. You don't need to calculate the inverse velocity pressure with regard to the position of Mars in July for a vertically installed horizontal sideway pendent water discharge device sprinkler.
Also aiming the discharge upward, is of no value. You want the discharge to run down the column where the fire source will be whether that be stored commodities or pool fires. You already have sprinklers overhead. The other issue with an upward pointed sidewall is that if it were the sprinkler to fuse first it could cold solder overhead sprinklers preventing them from activating so as stated previously, I'd seriously challenge a fire official on this idea. It just makes no sense in any way shape or form. All the sprinkler is intended to accomplish is to prevent the steel from reaching its point failure temperature. Typically that is in the neighborhood of 1200 (F). The direct water impingement on the columns has been tested and evidently found to accomplish this task with little regard for pressures and flow rate. You do want the sprinkler close to the column so that the discharge is collected within the web of the column. Whether you use a horizontal or vertical sidewall is more a matter of piping preference than functionality. They will both accomplish the same thing. So to quote the most famous inspirational speaker of all time, Shia Labeouf, JUST DO IT! Craig L. Prahl Fire Protection Group Lead CH2MHILL Lockwood Greene 1500 International Drive Spartanburg, SC 29303 Direct - 864.599.4102 Fax - 864.599.8439 CH2MHILL Extension 74102 [email protected] -----Original Message----- From: Sprinklerforum [mailto:[email protected]] On Behalf Of å... .... Sent: Tuesday, July 07, 2015 7:53 AM To: [email protected] Subject: Re: Column Protection We can use the sprinkler nozzle pressure, but as a means to the end of estimating how high the sprinkler will project water: 1. use the nozzle pressure with K-factor to get flow = Q, 2. with Q, divide by sprinkler orifice area (A) to get velocity. This is the max possible velocity as deflector will slow 90% of the spray. 3. from velocity, use Bernoullis at v2= 0 m/s velocity, to predict the height water will rise 4. note, once the water is outside the sprinkler, the pressure is essentially ambient, so P1 ~ P2 in Bernoulli's equation. 5. solve for z, maximum height the water will rise from vertically oriented sprinkler. This seems like a lot of energy and discussion for a relatively minor sprinkler design point. I mean, if we have gotten to the point of a fire where a column sprinkler is to save the structure, perhaps we earlier missed some more important fire protectioin design-issues, at least more important than sidewall horiztonal or sidewall down/up. Do you think sometimes we put more energy into debating the simple points, because they are simpler to think about, and we spend less time debating the not-so-clear subject material, because we don't want to spend the mental energy, even though that is the effort that would yield the-most-design value for the time? Scot Deal Excelsior Fire/Risk Engineering _______________________________________________ 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
