The wording has been (as long as I can remember) to not allow concentric reducers on the suction side. But the intent behind the wording is to eliminate high spots where air can accumulate and enter the pump in larger quantities. When a concentric reducer is used as an increaser, that's a non-issue. So it likely doesn't meet the letter of the standard, but I believe it meets the intent.
Ed Kramer Bamford Fire Sprinkler -----Original Message----- From: Sprinklerforum [mailto:[email protected]] On Behalf Of Travis Mack, SET Sent: Thursday, February 11, 2016 4:16 PM To: [email protected] Subject: Re: NFPA 20 around 1988 I have yet to get any pump test information, but I assume it has been tested properly. Thanks for the confirmation of the reducers. I was pretty certain that you couldn't use a concentric back in the day, but I didn't have the standard to verify it. What's funny is the pump is 8x6. They ran a 6" underground and piping up to the suction of the pump, then had to put an 8x6 flanged "increaser" to match up with the pump. You would think that some one would have had the idea back then that this didn't seem quite right. Travis Mack, SET MFP Design, LLC 2508 E Lodgepole Drive Gilbert, AZ 85298 480-505-9271 fax: 866-430-6107 email:[email protected] http://www.mfpdesign.com https://www.facebook.com/pages/MFP-Design-LLC/92218417692 Send large files to us via: https://www.hightail.com/u/MFPDesign On 2/11/2016 3:12 PM, Scott Futrell wrote: > I thought Brad would have the suction size answer! > > Suction size has been for some time based upon the pressure remaining above 0 psi when flowing at 150 percent of the rated capacity. So, 6" might be possible, but you'd have to verify the supply. > > Agree completely, no concentric on suction side. > > Scott > > Office: (763) 425-1001 x 2 > Cell: (612) 759-5556 > > -----Original Message----- > From: Sprinklerforum > [mailto:[email protected]] On Behalf Of > Brad Casterline > Sent: Thursday, February 11, 2016 4:08 PM > To: [email protected] > Subject: Re: NFPA 20 around 1988 > > No to concentric on suction side--- > Requires ECCENTRIC, top flat. > (if this is vertical in-line, different ballgame) On Feb 11, 2016 3:58 PM, "Travis Mack, SET" <[email protected]> wrote: > >> Was it ever permitted for a 1000 GPM pump to be supplied by 6" piping? >> Also, was it ever permitted to put a CONCENTRIC 8x6 reducer on the >> suction flange of a pump. >> >> We have an existing project where the owner was hoping to remove the >> pump and to supply from city water. I informed them that the water >> pressures on site were not compatible. They also have a pump that >> has been requiring a lot of maintenance. As I looked at the as-built >> plans (yeah, miraculously they had them for a building built in >> 1988), it shows a 6" supply for the >> 1000 gpm pump and the concentric reducer on the suction flange of the pump. >> >> In the most recent editions of NFPA 20, a 1000 gpm pump needs an 8" >> suction line. >> >> -- >> Travis Mack, SET >> MFP Design, LLC >> 2508 E Lodgepole Drive >> Gilbert, AZ 85298 >> 480-505-9271 >> fax: 866-430-6107 >> email:[email protected] >> >> http://www.mfpdesign.com >> https://www.facebook.com/pages/MFP-Design-LLC/92218417692 >> Send large files to us via: https://www.hightail.com/u/MFPDesign >> >> _______________________________________________ >> Sprinklerforum mailing list >> [email protected] >> >> http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprink >> l >> er.org >> > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkl > er.org _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkl > er.org _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
