Thank you for the information Art! In Europe we say that centre of pump must be equal or lower than the lower line for calculation net capacity in tanks. Therefore, we usually end up with pump room floor lower than the bottom of the tank to minimize unusable volume or we need to have to install pumps working with negative suction head and install small tanks above the pumps to fill them with water if necessary to avoid air in the systems (Negative suction is allowed but we try to avoid it).
Do NFPA have a similar rule concerning were the pump located and positive head? (I could not find when I did a search in my PDF version) Some people over here argue that if one uses a vortex plate one can still use this volume even if one have a pump room floor levelled with bottom of the tank and as well be on the positive head. If I understand you correctly, they are wrong? Why am I telling you this, well now we (in Sweden) need to use NFPA rules for EC sprinkler, ESFR, etcetera as well as our own standard (Swedish) which are on top of European standard. It starts to be vary confusing with all this rules and I just try to find some common ground. I'm sorry for my bad English. I hope that you understand me. Best regards/ Leif Glans www.lg-sprinklerkonsulten.com LG Sprinklerkonsulten PG Vejdes vag 15 351 96 Vaxjo Phone: +46 470-74 50 25 Fax: +46 470-74 50 26 Cell: +46 734-28 13 10 -----Ursprungligt meddelande----- Från: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] För art Skickat: den 15 januari 2007 20:23 Till: [email protected] Ämne: RE: Positive static head for tanks NO. As the tank empties or reduces to zero this head disappears. Assume the tank is nearly empty. That is the static head. If the tank is on a hill the elevation from base of the tank will provide you some static head. Art ATCO FIRE/Tiroly & Associates -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Leif Glans Sent: Monday, January 15, 2007 12:26 PM To: [email protected] Subject: Positive static head for tanks Hi! If one uses Centrifugal Pump according to NFPA 20, one should not use it if static suction lift is required (6.1.2, A 6.1.2) According to NFPA 22 4.1.3 for suctions tanks, the net capacity shall be the number of cubic meters (U.S. gallons) between the inlet of the overflow and the inlet of the vortex plate Is all of this volume considered positive head according to NFPA? Best regards/ Leif Glans www.lg-sprinklerkonsulten.com LG Sprinklerkonsulten PG Vejdes vag 15 351 96 Vaxjo Sweden Phone: +46 470-74 50 25 Fax: +46 470-74 50 26 Cell: +46 734-28 13 10 _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum
