For what it is worth - I agree with Roland on this.? The one point that is important is that if elevations were taken into account, the results for converting ot a 'K' factor are not valid.? The elevation loss will always be constant - if it is a 10 ft. elevation, the loss will be 4.33 psi.? If you run this loss?in the calculation of the 'K' factor, and you adjust for a new pressure or flow, the constant elevation loss will be re-adjusted as part of the calculation.? In order to be accurate, the elevation losses should be accounted for separately - calc the 'K' factor for the friction loss and end pressure required and re-apply the elevation losses.
Tom Prymak -----Original Message----- From: Roland Huggins <[EMAIL PROTECTED]> To: [email protected] Sent: Fri, 23 May 2008 11:19 am Subject: Re: Its tough getting old I disagree completely with what you said but agree completely with what you meant.? ? You can convert all such flow and pressure points to an EQUIVALENT k-factor (might as well call it as identified in 13 so as to differentiate from sprinklers)? ? It is NOT 100% accurate since it does not account well for significant changes in friction loss. Typically the change in flow is not that large so THE main rule of sprinkler hydraulics is applied. That being - it's close enough. For instance, the allowed k-factor range for a 1/2"orifice is 5.2 to 5.8. For OHGI at 130 sf requiring a flow of 19.5 gpm, the pressure for 5.2 is 14.1 psi and for 5.8 is 11.3 psi but we use a nominal 5.6.? ? The process is not intended to being driven by academic purity. It's intended to provide a reliable and repeatable process THAT WORKS.? ? Roland? ? On May 23, 2008, at 6:17 AM, Pip Males (Shared Services, IT, Manchester) wrote:? ? > nything with a flow and a pressure, like a system demand, can be > converted? > to a K factor."? >? >? >? > NOT STRICTLY TRUE:-? >? >? >? > Any pipe work system has a characteristic (system curve) similar to > (but > not? > the same as) a discharging device. As a pipe work system has pipes > which? > perform to a 1.85 law and discharging devices that perform to a > square law? > the form of the system curve is somewhere between a pure square law > and a? > pure 1.85 law.? >? ? _______________________________________________? Sprinklerforum mailing list? [EMAIL PROTECTED] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum? ? To Unsubscribe, send an email to:[EMAIL PROTECTED] (Put the word unsubscribe in the subject field)? _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum To Unsubscribe, send an email to:[EMAIL PROTECTED] (Put the word unsubscribe in the subject field)
