An adjustment for the water supply based on known conditions as determined by the purveyor and passed on to the AHJ for evaluation makes sense on several levels. It is a known condition, not one speculated on in general, as determined by the entity that controls the system and (reluctantly) hands us the data, empirically arrived at or modeled, and it's actually in 13. The capricious and arbitrary "cushion" is just that, capricious and arbitrary, and is not a supported methodology per the code. Now just adding a cushion is easier but that is based on data...Oh, wait...it's not based on any data. I'm much more comfortable forcing the purveyor to decide what the supply is, including all necessary adjustments, when I'm not allowed to gather any data for myself and the FMs solution is to have a catchall number that may or may not have any applicability either way. To have to increase a pipe size or two throughout, and hence increase the cost, in an area that has better than adequate water because another area may not, is not good engineering. Why bother with codes and committees of experts to develop those codes if the local guy wants to, and can. change the MINIMUM standard because he FEELS the need, whether he does it on a "because I said so" basis or gets it into an ordinance? Designers, lay-out techs, installers and IT&M guys are finding certification and licensing requirements being mandated in more and more places, presumably forcing these people to a higher level of professionalism, while people with lesser qualification in these areas are allowed carte blanche. I think we all remember the short lived national drive by fire marshals (mentioned yesterday I believe) to install a single sprinkler over residential cooking appliances. Apparently the driver for this was the statistic in 13D that most household fires start in the kitchen. The solution was that single sprinkler with no science or testing to back up the "good idea." I'm sure that most of us can think of the psychological bombshell that trumps any advantage that one head could provide: "I have a sprinkler system in my house." much less the actual utility. This type of thinking applies when mandating a cushion based on "a good idea." End rant!
On Wed, Sep 23, 2009 at 12:44 PM, Bobby McCullough <[email protected]> wrote: > Another consideration is 13 (2007) 23.2.1.2 which says an adjustment to > the public water supply shall be made for several conditions. More than > one AHJ in the Atlanta area requires the water test be adjusted and the > system demand a pound or three below the supply (adjusted). > > Bobby > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Matthew > J. Willis > Sent: Wednesday, September 23, 2009 3:03 PM > To: [email protected] > Subject: RE: Safety factor > > Not that I have seen. As far as 13 goes, you can design right to the > available supply. The different state and jurisdictions most times have > a > limit in place. > > R/ > Matt > > > Matthew J. Willis, CET > Automatic Fire Sprinklers > Norred Fire Systems L.L.C. > 318-387-1134 Voice > 318-387-1163 Facsimile > [email protected] > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Karen > Purvis > Sent: Wednesday, September 23, 2009 1:47 PM > To: [email protected] > Subject: Safety factor > > Can anyone tell me, does NFPA 13 or 14 say anything about a particular > safety factor to be used in the hydraulic calculations? > > > > 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) > -- Ron Greenman Instructor Fire Protection Engineering Bates Technical College Tacoma, WA Member: SFPE, ASCET, NFPA, AFSA, NFSA AFAA, WSAFM _______________________________________________ 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)
