Thom, This is going away from the original question and I'm starting to not care about that anymore since it was not a question about anything real, only about some fantasy situation I cooked up with parameters defined by me (I could have 17 cats per full orbit of Neptune as a flow rate). I was just curious about why we need to add an arbitrary outside hose stream to the sprinkler calc if it's covered with actual fire flow, but now I have another question. Which IFC edition are you looking at. My 2006 doesn't distinguish between hazards from 13. One table (B105.1) V-B (types based on footnote b), between 20,601 & 23,300 minimum flow of 4000 gpm @ 20psi (footnote c), as specified in B105.2 with the exception applied for fully sprinklered of "...fire flow of up to 75%, as approved...(but) not less than 1500 gpm...for the prescribed duration...." The 50% is only for one and two family dwellings. IBC 2006 defines V as being of any material allowed by the code and V-B has no fire resistive properties when the material is defined as such regardless of what it is.
On Thu, Jun 30, 2011 at 4:04 PM, Thom <[email protected]> wrote: > Just a quick retort: > Hose stream, hose allowance are not fire flow requirements. Fire flow is > set > in the IFC and this building (is not a LH occupancy S-2) only is eligible > for a 50% reduction in fire flow under the exception to B105.2. This would > limit the total building area of V-B construction to 13400 SF. If the > building is larger than that they don't meet fire flow even with the > reduction. The reduction itself is "allowed" but should not be applied > unless the AHJ approves of the lower flows. > > In closing if this is a 2-story building with 10000SF per floor, the > required fire flow would be 2750 GPM/2HR. With the reduction of 50% "if > allowed" the fire flow would be 1875GPM/3HR. (note the 3 HR duration, the > exception allows for a reduction in the flow for fire sprinklers, not in > the > duration.) > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Ron > Greenman > Sent: Thursday, June 30, 2011 3:48 PM > To: [email protected] > Subject: Re: Hose Stream > > Thom, > > This does relate to a real building, 2-story, B & S-2, V-B, fully > sprinklered and could have 1000 gpm total fire flow @ 20 psi but the FM > wants 1500 @ 20. The pump is fine and the civil just over spec'd the tank > size and included capacity for simultaneous full flow of hydrant and > sprinks > for 1 hour. The question though is theoretical because of the extra water > and that if that amount of water were present in separate tanks the outside > hose stream allowance for the sprinks wouldn't be required but is since > it's > in a single tank. And I couldn't remember the flow when I first asked the > question and used 450 + hose just as a number. Actual flow for the building > is 550 plus 250 but doesn't change the question since I could just be > putting it as A=sprink, B=Hose allowance, C=Hydrant. Tank capacity = A + C. > A + B < C so OK. C < Tank so OK. A + C = Tank so why do I need to include B > in the A calc at all? > > On Thu, Jun 30, 2011 at 12:22 PM, Thom <[email protected]> wrote: > > > Brett: Be careful how you phrase that. The outside Hyd. May be the sole > > water supply for fire flow, in which case depending on building > > construction > > and occupancy and size could require up to 8,000 GPM for 4 hours, "Fire > > Flow" per the IFC appendix "B" table B105.1. > > We need a lot more info before we can definitively say that a 1500GPM > hose > > allowance on top of sprinkler calc is adequate. Is the building fully > > sprinklered per 13? What is the construction, total area, height, > > occupancy, > > who is AHJ and What is response time? > > > > So many questions?? So Little time! > > I'm not trying to start a new thread, So please don't go off on > specific's, > > I'm just saying absolutes are rare. > > > > Subject: RE: Hose Stream > > > > I would say that your system demand is 450 gpm and you have included a > > hose > > stream allowance of 1,500 gpm which is above and beyond the minimum > > requirement. > > Brett Foreman > > > > > > > > _______________________________________________ > > 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 Technology > Bates Technical College > 1101 So. Yakima Ave. > Tacoma, WA 98405 > > [email protected] > > http://www.bates.ctc.edu/fireprotection/ > > 253.680.7346 > 253.576.9700 (cell) > > Member: > ASEE, SFPE, ASCET, NFPA, AFSA, NFSA, AFAA, NIBS, WSAFM, WFC > > They are happy men whose natures sort with their vocations. -Francis Bacon, > essayist, philosopher, and statesman (1561-1626) > _______________________________________________ > 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 Technology Bates Technical College 1101 So. Yakima Ave. Tacoma, WA 98405 [email protected] http://www.bates.ctc.edu/fireprotection/ 253.680.7346 253.576.9700 (cell) Member: ASEE, SFPE, ASCET, NFPA, AFSA, NFSA, AFAA, NIBS, WSAFM, WFC They are happy men whose natures sort with their vocations. -Francis Bacon, essayist, philosopher, and statesman (1561-1626) _______________________________________________ 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)
