IMHO the intent of the rule is to get the inlet away from the suction so as to minimize the potential for air entrainment, as has been discussed. As written the inlet needs to be on the opposite half of the tank. This could mean a ½ diameter away, or maybe at least 90 degrees along the outside of a round tank from the pump suction nozzle.
Could it be located closer to the suction without causing problems – probably, especially on a 90 ft. diameter tank, but that is not how the standard is written. Perhaps it may be time for a suggested improvement to be sent to the NFPA 22 committee. Remember also that the fill line for a 90 ft. diameter tank is likely going to be much larger than one for a 20 ft. diameter tank, which makes a difference as well. -Mark Note: None of the above should be interpreted as an official opinion or position of the NFPA 22 technical committee. [Visit our Website at www.SummitCoUS.com]<http://www.SummitCoUS.com> Mark Sornsin Sr. Fire Protection Engineer Direct: 701-499-1391 Cell: 701-526-8585 From: Sprinklerforum [mailto:[email protected]] On Behalf Of Kyle.Montgomery Sent: Thursday, February 28, 2019 9:42 AM To: [email protected] Subject: Suction Tank Question NFPA 22 states the following: 14.4.10.1 Pipes for the automatic filling of suction tanks shall discharge into the opposite half of the tanks from the pump suction pipe. Does that mean that the fill line has to be directly across (opposite) the tank from the pump suction? If I’ve got a tank with a diameter of 90 feet, do I really need to run the fill line all the way around to the other side or is there an acceptable minimum distance? It seems like overkill to require the fill line to be 90 feet away from the suction. I mean, if it was a small tank with a diameter of 20 feet, then only 20 feet away would be acceptable, right? Any thoughts? Kyle Montgomery [cid:[email protected]] Aero Automatic Sprinkler Co. 21605 N. Central Ave. Phoenix, AZ 85024 Direct: 623.580.7820 Cell: 602.763.4736 [email protected]<mailto:[email protected]> ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please visit http://www.symanteccloud.com ______________________________________________________________________
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