I laid out a 11.4 x 11.4 pattern (130 sq ft) and drew three rings. 1st ring included 4 sprinklers (520 sq ft). 2nd ring included 12 sprinklers (1520 sq ft). 3rd ring included 24 sprinklers (3120 sq ft). The numbers are comparable to NFPA ~1500 sq ft and the DoD ~ 3000 sq ft.
The ring theory makes sense in this context. NFPA is looking for a two ring design and DoD is looking for a three ring design? Was this purposeful? If so it provides the basis for the 1500 sq ft minimum design area. Using this approach, the 900 sq ft design looks like it has a very small margin of error. If we have this two ring NFPA design, what led to the development of the area/density curves where density is decreased as design area is increased? Bill Brooks Pittsburgh, PA -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Joe Hankins Sent: Friday, March 16, 2007 2:49 PM To: [email protected] Subject: Re: Burning Ring of Fire (and the Flames Shot Higher) Bill, You are correct. Sometimes politics prevails. Joe Brooks, Bill wrote: >Joe, > >I thought I understood your train of thought until I started considering the >area reduction for quick response sprinklers. How many rings are there with >a 10 ft ceiling height QR design? 900 sq ft or 5 heads. > >Can I conclude the ring theory falls apart when this design approach is >used? It looks like you don't have your 1 ring cushion in this case. > >Bill Brooks >Pittsburgh, PA > >-----Original Message----- >From: [EMAIL PROTECTED] >[mailto:[EMAIL PROTECTED] Behalf Of Joe >Hankins >Sent: Friday, March 16, 2007 11:56 AM >To: [email protected] >Subject: Re: Minimum Supply Pressure > >The idea that there is a huge difference between a 5-sprinkler fire and >a 15- or 30-sprinkler fire seems logical on the surface, but if you know >how sprinklers operate, you know they operate in rings. The heat that >operates sprinklers spreads in a circle from the fire origin. For >symetrically-spaced sprinkler system where the fire starts centered >among 4 sprinklers, there are 4 sprinklers in the first ring around >ignition, so there is virtually no difference between a 1-sprinkler >fire and a 4-sprinkler fire. If those sprinklers don't control the fire, >then any (and all) of the 12 sprinklers in the next ring can operate, >meaning that there is very little difference betwen a 5-sprinkler fire >and a 16 sprinkler fire. If you get into the next ring, then the number >is 36 sprinklers. So, the 1-ring "safety factor" between 4 and 16 >sprinklers is the same as the 1-ring safety factor between 16 and 36 >sprinklers. A 1-ring "safety factor" is not overkill in my book! >_______________________________________________ >Sprinklerforum mailing list >[email protected] >http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum > > > _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum
