UNCLE On Tue, Sep 16, 2014 at 1:31 PM, Cahill, Christopher <[email protected]> wrote:
> Don't blame the engineer on gov't. I try to pull it out but they usually > make me put back in. > > > Chris Cahill > Fire Protection Engineer > Burns & McDonnell > 952-656-3652 > [email protected] > > > -------- Original message -------- > From: Lamar Vaughn > Date:09/16/2014 12:07 PM (GMT-06:00) > To: Sprinkler Forum > Subject: Re: Water Velocity > > It would really be good if this thread could be shared with the engineering > community at large. I STILL get specifications that require a maximum > velocity of 20 fps. Very costly, especially when you have a good water > supply. > > Lamar Vaughn, SET > > On Tue, Sep 16, 2014 at 12:03 PM, Roland Huggins < > [email protected] > > wrote: > > > actually the difference between the results for D-W and H-W does not vary > > consistently (alas there is not a linear relationship). To require using > > D-W at very high velocities is unnecessarily conservative. At these > > velocities the pressure loss is so high that it is self regulating so > > typically occurs only is limited sections of the system. With all the > > averaging etc that our process entails, why get anal on ONE piece of the > > puzzle? Having said that, one could argue that one should account for > the > > velocity pressure in the discharge calc at high velocities BUT that is > > needed only when you really have such velocities (like in a water spray > > deluge) verses seeing an assigned value from our process. > > > > > > Roland Huggins, PE - VP Engineering > > American Fire Sprinkler Assn. --- Fire Sprinklers Saves Lives > > Dallas, TX > > http://www.firesprinkler.org > > > > > > > > > > > > On Sep 15, 2014, at 1:56 PM, Damien Shannon <[email protected]> > wrote: > > > > > 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). > > > > > > > > > > _______________________________________________ > > 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
