We calculate nearly everything we touch, if only for our own purposes. The rest we use the hundred plus years of combined experience the principals have to decide things like that. We have seen enough to know that in many cases when people have gone in and added 1-2 sprinklers they have over taxed a system IF IT HAD TO FLOW ITS ENTIRE REMOTE AREA. Since sprinklers work so well, that usually doesn't happen however.
We were asked to add 6 heads to a system recently that previously had approximately 30 sprinklers. We were told to add them in a specific location adjacent to the supply for the system. I KNOW THE FOLLOWING RESULTS ARE EXTREME AND UNUSUAL - but we refused to do so without proving the additional heads would work. When we calc'ed it we were shocked to find that the entire system was installed incorrectly with improper spacing and end head pressures and had a pressure deficit of HUNDREDS of lbs. I am so grateful that we did not just do what the EOR asked us to do. I would say you need to learn to calculate and buy some software to keep you out of trouble IMHO. Greg McGahan Operations Manager Living Water Fire Protection 1160 McKenzie Road P.O. Box 877 Cantonment, Florida 32533 (850) 937.1850 | Fax (850) 937.1852 | Cell (850) 554.3231 [email protected] -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Karen Purvis Sent: Wednesday, February 10, 2010 3:24 PM To: [email protected] Subject: RE: pipe sizing question I'm not talking about calculations just about selecting the actual size of the pipe. Should I use a 1" pipe on 2 sprinklers or use a 1" pipe as long as the gpms are less than 10. I just want to know how people know or choose the size of pipe they use for each branch, sprig and main. Karen Purvis Senior Designer Facility Systems Consultants 713 South Central Street, Suite 101 Knoxville, TN 37902 ph.865-246-0164 fax 865-246-1084 -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Matt Grise Sent: Wednesday, February 10, 2010 4:23 PM To: '[email protected]' Subject: RE: pipe sizing question In some of the jurisdictions around here the AHJ's do allow submittals without calcs for small add/relocate, and tenant improvement work as long as it does not exceed the original hydraulic design of the shell system (adjusting an OH2 retail system to accommodate a LH office, etc). I am familiar with the pipe drop charts you are talking about. The main issue I see with those is that it could be difficult to account for over-flow at each head, so you could end up with more water flowing than you anticipate. Matt Grisé PE*, LEED AP Sales Engineer Alliance Fire Protection *Licensed in KS & MO 913.888.0647 ph 913.888.0618 f 913.927.0222 cell www. AFPsprink.com -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Travis Mack, SET Sent: Wednesday, February 10, 2010 3:18 PM To: [email protected] Subject: Re: pipe sizing question It is my understanding that you need to provide calculations per NFPA 13, or use the pipe schedule method where it is allowed. You can estimate with tables showing pressure drops, but that likely won't suffice for submittal to the local authorities in any where that I have done work. On 2/10/2010 2:08 PM, Karen Purvis wrote: > We mainly do new and add-on systems a few retrofits no grids no high piled > storage no extra hazard. Usually all light and ordinary hazard. > > Karen Purvis > Senior Designer > Facility Systems Consultants > 713 South Central Street, > Suite 101 > Knoxville, TN 37902 > ph.865-246-0164 > fax 865-246-1084 > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of > [email protected] > Sent: Wednesday, February 10, 2010 4:12 PM > To: [email protected] > Subject: RE: pipe sizing question > > For what kind of systems, new, retrofits, tree, grid, etc.....? > > > Craig L. Prahl, CET > Fire Protection Specialist > Mechanical Department > CH2MHILL > Lockwood Greene > 1500 International Drive > PO Box 491, Spartanburg, SC 29304-0491 > Direct - 864.599.4102 > Fax - 864.599.8439 > [email protected] > http://www.ch2m.com > > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Karen Purvis > Sent: Wednesday, February 10, 2010 3:57 PM > To: [email protected] > Subject: pipe sizing question > > This may seem like a very newbie question but here goes. How do most of you > guys size your pipe other than using a hydraulic calculation program? I have > been using a pressure drop chart that list pressure drop and velocity in > schedule 40 pipe for water at 60°F per 100 feet drop. So far this has worked > for me but now I have someone questioning my method. Should I be going back > to the pipe schedule method? > > > > Karen Purvis > > Senior Designer > > Facility Systems Consultants > > 713 South Central Street, > > Suite 101 > > Knoxville, TN 37902 > > ph.865-246-0164 > > fax 865-246-1084 > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://fireball.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 > [email protected] > http://fireball.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 > [email protected] > http://fireball.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) > -- Please feel free to call if you have any questions or comments. Sincerely, Travis Mack, SET MFP Design, LLC 2508 E Lodgepole Drive Gilbert, AZ 85298 Office (480) 505-9271 Fax (866) 430-6107 _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.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 [email protected] http://fireball.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 [email protected] http://fireball.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 [email protected] http://fireball.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)
