So purely along the lines of Andy Rooney's 'have you ever wondered why' :) ... FM Datasheet 2-0, while not limiting the allowable velocity, does require that when velocity exceed 30ft/sec, that the calculation be performed via the Darcy-Weisbach Method rather than the Hazen-Williams. Entertainment value only, but would seem that the variance between results in Hazen-Williams versus Darcy-Weisbach become more apparent with higher velocities. The 30ft/sec limitation (for application of Hazen-Williams calculations) in FM 2-0 is strangely close to the 10m/sec (32.8ft/sec) limitation in EN 12845 Rules for Automatic Sprinkler Installations (previously BS 5306).
On 15 September 2014 21:23, Parsley Consulting <[email protected]> wrote: > Roland, > A mutual friend of ours who works up in Quincy described for me a > question he once had with a caller who wanted to know in which edition of > -13 the 32 ft/sec requirement had been removed, and why. > This friend searched through the library there back to the first > sprinkler standard from 1896, and found that it had NEVER been part of > -13. The individual he was dealing with accused him of being an imbecile > and a deceitful one to boot, and promptly hung up. > Joe Hankins told me the same story. > *Ken Wagoner, SET > *Parsley Consulting*** > *350 West 9th Avenue, Suite 206 > *Escondido, California 92025 > *****Phone 760-745-6181* > Visit our website <http://www.parsleyconsulting.com/> *** > On 9/15/2014 1:01 PM, Roland Huggins wrote: > >> Next time you even start to think of any basis for imposing a velocity of >> 32 ft/s, take a hammer and smash a finger. Hopefully the pain will divert >> you from wasting your time especially if you’re assuming you are dealing >> with facts. I’ve heard numerous conclusion as to why the mystical 32 ft/s >> existed. Only one has any chance of being valid. Joe Hankins told me long >> ago that FM initially imposed a velocity restriction after hydraulic calc’s >> entered the scene and folks started designing gridded storage systems with >> 1 inch BLs. For ever other basis, I can hear Andy Rooney saying - Have you >> ever wondered why …... >> >> Roland >> >> >> Roland Huggins, PE - VP Engineering >> American Fire Sprinkler Assn. --- Fire Sprinklers Saves Lives >> Dallas, TX >> http://www.firesprinkler.org >> >> >> >> >> >> On Sep 12, 2014, at 5:51 AM, Brad Casterline <[email protected]> >> wrote: >> >> Damien, will you mail me those snaps too please? I have heard the pipe >>> schedules were derived by increasing the size when the velocity reached >>> about 32 ft/sec. Figuring out approximate flow per head and average >>> densities, etc, will give me something to do as I sit at the kitchen >>> table >>> and drink beer tonight. Thanks. >>> >>> Good luck Jeremy! >>> >>> Brad >>> >> _______________________________________________ >> 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 > -- *Damien Shannon* _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
