Todd: You could always reduce the underground back to 4" just before entering the building, giving you a lot of pipe dia. Between reductions. With the majority of the underground still 6" that should help with your concern for the neg. suction pressure at 150%.
Thom McMahon, SET Firetech, Inc. 2560 Copper Ridge Dr P.O. Box 882136 Steamboat Springs, CO 80488 Tel: 970-879-7952 Fax: 970-879-7926 -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Todd Williams Sent: Tuesday, May 26, 2009 6:59 PM To: [email protected] Subject: Re: reducing suction line The pump is a 250 gpm; a minimum of 4" suction is required (OK, 3-1/2). I did a project with the same size pump 2 years ago, taking suction from 2 tanks with a 4" suction line. When we tested the pump at 150%, we drew the suction down to -1 psi. There is going to be more suction pipe on this than the last, so I told them to use 6" because I was afraid that the suction would go below -3 psi at the acceptance (per 5.14.3.2). So the 6" sizing was my doing for those reasons. I provided the tank and suction pipe sizing and the rest of the design is up to others. We also cannot increase the size of the pump, as someone suggested because we only have single phase power and 250 gpm at 60 psi is the largest we can get. I am now finishing up the final piping arrangement for the pump and was questioning the reducer arrangement. At 07:54 PM 5/26/2009, you wrote: >Todd, > >What did you do to deserve such Karma? This guy will probably save >them into a black money hole. Question: If they haven't run mains why >do you get a 6" pipe when you only need 2 1/2"? Why have they hired >you you if they're listening to they're amateur? The problem of the >empty spot is real, I've seen it, and kudos to you for just suspecting >the arrangement is bad. I think the long reducer (I'm seeing a giant >underwriters' playpipe) will work but just how long? Maybe the same >ratio as the playpipe but 6" to 2 1/2" instead of 2 1/2" to 1 1/8". >The stepping with a straight pipe of sufficient diameters might also >work. Why can't you just get a 4" UG? > >On Tue, May 26, 2009 at 4:41 PM, Todd Williams <[email protected]> wrote: > > That's the type of thing I am looking for. My original thought before > > I posted this was a 6x4 90, the 10 diameters and a 4x2-1/.2 eccentric > > reducer. Space may be an issue and when they run the underground > > mains, I'll have to figure out the exact arrangement. This is a > > church addition and the project is being run by the building > > committee. One member deals with sprinklers a little bit at work and > > has been thoroughly annoying. He is doing the layout for the tanks > > and mains into the building (to save money). I'm trying to give input > > as best I can, but I'm not sure what the final product will look like. > > > > > > At 06:48 PM 5/26/2009, you wrote: > >>I think you might have problems Todd. A pump off an aboveground tank I did > >>at a Loews 2 years ago developed "catching-up" issues. > >>We were transferring from normal to emergency and during the switchover the > >>supply bottomed out on start-up. We had transferred after switch-over but > >>when the pump came up to speed, the main dropped to vacuum at the > suction of > >>the pump. I had a -30/30 gauge on the suction and she went from > 4 PSI to -5 > >>(I think) for about 30 seconds until the supply came back. They had run a > >>10" right to the pump and put in 2 eccentrics, 10x8 and 8x6 to > the 6" inlet. > >>I remember it had a 10" bypass with the jockey off either side and the > >>jockey controller showed pressure while we took a dive. I'm kind > of ham and > >>eggs to the science end of it but I think if you could reduce once, 10 > >>diameters, reduce again, 10 diameters, you might avoid this. Maybe > >>something else but it was a surprise fer sure. > >> > >>Go Red Sox!! > >> > >> > >>Anybody ever have a problem going with this dramatic a reduction? > >> > >>At 02:17 PM 5/26/2009, you wrote: > >> >Todd, > >> > > >> >Can you use a Victaulic #51 6" x 2 1/2" groove eccentric and connect to > >> >flanges using vic flanges? > >> > > >> >Jim Johnston, P.E. > >> >Fire Protection Engineer > >> > > >> >I have a situation where a 6" main from a tank is going to need to be > >> >connected to a 2-1/2" suction flange on a pump. The largest eccentric > >> >reducer I can get is 4 x 2-1/2. Can I back-to-back reducers without > >> >causing problems? Could I used a 6x4 90 on the suction line and then > >> >elbow back to the pump (with at least the minimum distance reqd)? Any > >> >other thoughts? > >> > > >> >Todd G. Williams, PE > >> > >>_______________________________________________ > >>Sprinklerforum mailing list > >>http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum > >>For Technical Assistance, send an email to: [email protected] > >> > >>To Unsubscribe, send an email to:[email protected] > >>(Put the word unsubscribe in the subject field) > > > > Todd G. Williams, PE > > Fire Protection Design/Consulting > > Stonington, Connecticut > > www.fpdc.com > > 860.535.2080 > > _______________________________________________ > > Sprinklerforum mailing list > > http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum > > For Technical Assistance, send an email to: [email protected] > > > > To Unsubscribe, send an email to:[email protected] > > (Put the word unsubscribe in the subject field) > > > > > >-- >Ron Greenman >at home.... >_______________________________________________ >Sprinklerforum mailing list >http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum >For Technical Assistance, send an email to: [email protected] > >To Unsubscribe, send an email to:[email protected] >(Put the word unsubscribe in the subject field) Todd G. Williams, PE Fire Protection Design/Consulting Stonington, Connecticut www.fpdc.com 860.535.2080 _______________________________________________ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field)
