I have to connect 50 heat detectors, 7 smoke detectors, manual pull stations, strobes and some horns/strobes/bells to a conventional (non addressable) class A fire alarm panel. I am researching the NFPA 72 and found out the following. The heat ducts need a zone. Each room needs a zone. The manual pull stations need a zone as do the strobes/hornes/bells. I figure for a Monaco 2 conventional panel, I should get 4 zones per expansion card and will require a backplane card for my remote system annunciator. If I have 12 rooms, I calculate that I will require 15 zones, i.e. a zone each for 12 rooms, a zone for the heat ducts, a zone for the horns/strobes/bells, a zone for the pull stations. That makes 15 zones. The electrician estimated 30 zones without giving it a detailed look. I wonder if I am missing something since I am only comming up with 15 zones.