3 story buidling, 1900, first floor currently B and upper are R-2. Want to add R-2 at rear of First Floor. If I use the prescriptive method, is it possible not to put sprinklers in new r-2 on first floor, depending on score of course. I am planning on a fire barrier between new work and old so that it is its own fire area. Also a simple question. Why do you get a ht. and area increase for R-2 if sprinkled..I mean according to the Code R-2 has to be sprinkled regardless.