Todd: I believe you want to use the '6 in. to bottom of elbow' option. Once flow begins to the pump, the pump will siphon the water up the elbow and out the tank until air can enter the pipe - which will occur when the level in the tank drops to the 6 inch depth (where the opening of the elbow is positioned above the floor of the tank).
As to the upper elevation of the water, I think you can assume full depth of the tank - at least to the over-flow pipe. Mark A. Sornsin, PE Fire Protection Engineer Ulteig Engineers, Inc. [EMAIL PROTECTED] www.ulteig.com -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Todd Williams - FPDC Sent: Friday, August 01, 2008 8:05 AM To: [email protected] Subject: effective tank volume I am working on a project where the water supply for the facility will be fed from concrete tank(s). The absolute volume (completely full) of the tank is 10098 gallons. A 6" suction line with elbow & anti-vortex plate will need to be installed. According to NFPA 22, the face of the suction elbow has to be a minimum of 6" above the bottom of the tank. The take-out for the elbow is 8" and the top of the pipe will be 4" (+/-) above that. I am trying to calculate the effective or usable volume in the tank based on what my minimum height above the floor can be relied on for suction. Would it be the 6" to the bottom of the elbow? 14" to the center line of the suction pipe? 18" to the top of the suction pipe? The tank is 10 feet tall, so this could have a significant impact on available water. (BTW, I am already assuming that the tank will only be filled 9" to 12" from the top; would that be reasonable?) Todd G. Williams, PE Fire Protection Design/Consulting Stonington, Connecticut www.fpdc.com 860.535.2080 _______________________________________________ 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)
