"Anything 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. It is quite a common practice to take the demand point and use the flow and pressure in the discharging device formula (Q = K√P) to calculate a k-factor for the system. This is then used to produce a square law system curve or to add an existing calculated system to a larger system. This is incorrect and should be avoided whenever possible. The following graph illustrates the problem. The system curve was generated by effectively producing lots of demand points by setting the minimum pressure requirement at the most remote head to various values. The nozzle characteristic is a square law curve produced by equating the system to a k-factor derived from the (Q = K√P) formula using the flow and pressure at the original demand calculation. As can be seen the only place that the curves agree is at the demand point. Of course if you use a computer program and model all systems discharging in the one model you get the true result and do not have a problem. Best Regards, Pip Males CAD Manager(FIRECAD(r)) Tyco Fire & Integrated Solutions Manchester UK -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of George Church Sent: 22 May 2008 20:26 To: [email protected] Subject: RE: Its tough getting old K equals q over radical p ********************************************************************** Tyco Fire & Integrated Solutions (UK) Ltd. Registered in England, Number 1952517 Registered office: Tyco Park, Grimshaw Lane, Newton Heath, Manchester M40 2WL, England This e-mail is intended to be delivered only to the named addressee(s) and may contain information that is confidential and proprietary. If this information is received by anyone other than the named addressee(s), the recipient(s) should immediately notify the sender by e-mail and promptly delete the transmitted material from your computer and server. In no event shall this material be read, used, stored, or retained by anyone other than the named addressee(s) without the express written consent of the sender or the named addressee(s). This footnote also confirms that this email message has been swept by MIMEsweeper for the presence of computer viruses. www.mimesweeper.com **********************************************************************
_______________________________________________ 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)
