The design criteria for CMSA sprinklers in Table 14.3.1 are a carryover from the 2007 Edition where the requirements were the same for palletized storage of Class III or Class IV commodities up to a height of 25 ft. (Check it out - You need the same number of heads at the same pressure for 20 ft storage of Class III as for Class IV to 25 ft.)
The equivalent density using CMDA sprinklers for Class IV to 25 ft. is 0.54 fpm/sq ft over 2,000 sq ft. (0.39 from Fig. 14.2.4.1 x height adjustment of 1.38 from Fig. 14.2.4.3). The flow rate for this arrangement would be 1080 gpm such that going to CMSA would reduce your overall flow for your situation. (Using high temp heads would reduce the density to 0.41 gpm/sq ft, which is similar to what's required for CMSA heads.) David -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of J.P. Merlino/ Ing.L.Lagomarsino y Asoc. Sent: Monday, December 20, 2010 3:44 PM To: [email protected] Subject: Class III Solid Pile Protection Criteria We have doubts regarding criteria for protection of the following: Class III, solid pile Storage height: up to 20 ft Máximum building height 30 ft NFPA 13 2010 Edition As we understand, the code gives two options which are: 1) Per 14.2.4, Control Mode Density Area:Figure 14.2.4.2 With ordinary temperature, K=11,2 sprinkler we need 0,215 gpm/sq ft over 2000 sq ft. Flow rate equals 430 gpm 2) If we go to 14.3, Control Mode Specific Application, Table 14.3.1, for same conditions, we are required to have 15 sprinklers with K= 11,2 operating with a minimum discharge pressure of 25 psi. Flow rate equals 840 gpm and density is 0,43 gpm/sq.ft. Are both cases valid for the hazard we are protecting? Why such a large difference in terms of flow and density? Best regards and thanks in advance J.P. Merlino _______________________________________________ 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)
