Thanks Mark. That sheds a lot of light. Not definitive but adds a bit of evidence from actual experience not previously factored in. From my understanding the seven psi minimum pressure has nothing to do with pattern development, distribution, unseating the stopper (all previously discussed), among other induced explanations but merely because that is the pressure applied in the testing protocol. Now that number may have been derived at for a reason not stated but I know of no written document alluding to why 7 psi was chosen.
On Thu, Dec 10, 2009 at 7:35 PM, Phelps, Mark <[email protected]> wrote: > I can shed a little fact on this subject, regardless of testing/listing > issues. We have done patern testing for diffefent reasons over the years, and > here is what I know. Pattern has very little to do with pressuer and > everything to do with deflector design. Increasing pressure increases > density, not throw. An external deflector will simply atomize the water > stream if too much pressure is applied, it's purpose is to shape the > pattern. Just my experience, for what its worth. > Mark at Aero > > -----Original Message----- > From: [email protected] > <[email protected]> > To: [email protected] <[email protected]> > Sent: Thu Dec 10 15:24:19 2009 > Subject: Re: 13 residential sidewalls > > The potential flaw in your assumptions is that the pressure goes up > with throw while width remains constant. The problem with the cut > sheets for residential sidewalls is that do not address the 0.10 > situation > > Sent from my iPhone > > On Dec 10, 2009, at 2:38 PM, Roland Huggins > <[email protected]> wrote: > >> For starter I have always assumed (yea I now what that means but I've >> always been one so go with your strengths) that it was the sideways >> throw that is the challenge based on the fact that the water momentum >> is in the same direction as the throw across the room but changing the >> direction 90 degrees would seem to ore adversely affected by small >> changes in distance covered. >> >> Applying Ron's rule to avoid the slippery slope inducted Aristotelian >> explanations of phenomena, tells me to simply check the cut sheets and >> embrace their guidance. >> >> Roland >> >> >> On Dec 10, 2009, at 9:38 AM, Todd - FPDC wrote: >> >>> I get all that. But I assume most of the pressure in a sidewall is >>> for >>> throw and not width, how can we justify a significant decrease in >>> pressure based on a decrease in width alone? >>> >>> >> >> _______________________________________________ >> Sprinklerforum mailing list >> [email protected] >> http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum >> >> For Technical Assistance, send an email to: [email protected] >> >> To Unsubscribe, send an email to:Sprinklerforum- >> [email protected] >> (Put the word unsubscribe in the subject field) > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > > For Technical Assistance, send an email to: [email protected] > > To Unsubscribe, send an email to:[email protected] > (Put the word unsubscribe in the subject field) > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > > For Technical Assistance, send an email to: [email protected] > > To Unsubscribe, send an email to:[email protected] > (Put the word unsubscribe in the subject field) > -- Ron Greenman Instructor Fire Protection Engineering Bates Technical College Tacoma, WA Member: SFPE, ASCET, NFPA, AFSA, NFSA AFAA, WSAFM _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field)
