The design should be what the stakeholders agree to. The design could be any number of different options.
PET, in a one-ton pile of fun? That is a big pool of melted plastic if the sprinklers don't control the fire. Looks like from 2007 NFPA 13 Table 15.2.5(a) that the pile made by your PET is from 20-25 ft deep (based on your choice of hose stream). But if that is true, the 0.6 over 2,500 you chose does not match those dimensions on the building height. 0.6 over 2,500 is for PET under a ceiling taller than 30 ft. Is the PET recycled plastic containers? Wood pallets: Best to store them outside, 25' from any building opening, if you can keep them secure. If you do store inside, what leads you to believe the owner will remember to keep pallets stored below 11.5 ft when PET and Cartons are stored to 20 ft and higher under the 27' high roof? The ESFR option you chose (K25.2 @ 15psig) is good for 25 ft storage under 30 ft ceiling. And although it doesn't say so, it will protect against plastic pallets, not up to 25 ft, but higher than 8 ft. Cartons/Boxes: Assumedly cardboard, no plastic: Class III commodity. Your pick of sprinklers for this commodity being K25.2 at 15 psig suggests up to 25 ft storage under 30 ft building. If the client was sold on the idea that they are going to need a pump and cistern, given virtually any practical storage option at this facility, then I would go with ESFR. I would go with ESFR sprinklers. ESFR sprinklers will be more difficult to design and install correctly as compared to CMSA, but your insurance carrier, hopefully, can assist in the details with obstructions. ESFR will allow for a slightly smaller cistern. Added bonus is that K25.2 ESFR at 15 psig is prescribed to suppress fires in PET stored to 20 ft high and control fires in PET stored to 25 ft. And since you MAY not be encumbered by a legal system that dissuades worker hose-stream intervention, I have found most workers in all but the most onerous of managed facilities, are motivated to suppress a fire when they realize their family income is at stake from a fire about to take their livelihood away. Risky to have workers fight fire, but the consequences of no job are not attractive either. The workers will, in most cases, be able to get a hose stream on the fire early enough to kabosh it. Provide the workers with training & 150 ft of 1.5 inch hose with 1.5 inch standard nozzle with 140 psig at the hose connection, not the nozzle. Ala pues, we are talking about putting the fire out, not just designing for designing's sake, correct? Scot Deal Excelsior Fire Engineering On Thu, Mar 24, 2011 at 6:00 AM, [email protected] < [email protected]> wrote: > Good morning. > I have a storage building that has: > - Carton boxes over the floor with a height of 11.5 ft. > - PET in bags, where each one weigh is 1 TON > - Wood Pallets over the floor with a height of 11.5 ft. > > The building has 27ft height. > > Looking in NFPA 13 ed.2007 I found the following design criteria: > - Wood pallets: Table 12.12.1.2(d) = 12 head K25.2 @ 15psi + 250gpm @ > 60min. > - Carton boxes: Table 14.4.1 = 12 head K25.2 @ 15psi + 250gpm @ 60min. > - PET: Table 15.2.5a = 0.60 @ 2,500 sq.ft. + 500gpm @ 150min. > > All the materials are mixed in the floor, so I need to decide for just one > design criteria for the entire building. > > The density for K25.2 @ 25psi is 0.98gpm/sq.ft. if the maximum "As" per > head is 100 sq.ft. This is more that 0.60 gpm/sq.ft. > > I think that wood pallets and carton boxes needs more water to suppress. > And PET need less water to control, but more heads will open because > generate mote heat that carton or wood pallets. > > What should be the design criteria for this storage building? > _______________________________________________ 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)
