This is a tough one. For 13D systems, I usually propose to calc 3
sprinklers instead of two and the AHJs have so far gone along. I can
only think of one 13R system where that applied. The AHJ on that one
went along with using the head requirements for the maximum pitch (I
think the pitch was
I can think of a few things. Since we're doing a 0.05 density we could
go up to 0.06 or 0.07 at the maximum spacing (15x14 actual equals
16x16) kind of like FM degrades the co-efficient for hydrant outlets
relative to NFPA. We could go up one area so if we'd normally be using
the psi/gpm numbers
Dave
In every instance we have to do a 3 head calc when there are at least 3
heads in the room where the steep pitched roof is (over 8:12). We've also
had to use the UL listed flow required for the head up to 8:12 pitched
ceilings which is 18gpm per head. These homes are also usually large homes
Three AHJ's all different all 13D.
#1
Requires 2 head calc for all homes under 5000 Sf @ 0.05
Requires 3 head calc over 5000 Sf @ 0.05
Requires 4 head calc for over 8/12 any size, also 0.10, also only recessed
heads (He will accept recessed heads that are not listed for up to 8/12, but
will not
I like AHJ number three since he's not guess engineering. The more is
better/save the building with a guess tweaked life safety system
design is the second biggest deterrent (after the water guys and
their 4 minimum residential lead-ins and the $14K one inch tap
fees--my personal favorite although
