This brings us to the last concern–the local building inspector’s statement that he won’t approve heat or smoke detectors to be installed where they are “exposed to the elements.” Detector manufacturers, UL and NFPA 72 all prohibit smoke detectors from being installed in environments that are outside of their listing requirements. Therefore, you will have to use heat detectors that have been listed for the application you have encountered. These detectors will be hermetically sealed so they are dust and moisture proof. A weatherproof box will be required and splices within the box should be accomplished with silicon-filled connectors. The conduit and connectors must also be listed for outdoor use. (Don’t forget to add lightning arrestors, UL497B, for all fire alarm wiring you run outdoors, per Article 800 of the NEC.) I don’t think the building inspector will veto outdoor listed equipment. If he still doesn’t want the detectors “exposed to the elements,” then it becomes the school’s problem and they will have to build a roof over the landing(s).
You are the fire alarm expert
I can see how you could feel overwhelmed by all of these issues being hurled at you from both sides. But when each problem is addressed individually, you should have no problem getting the job done correctly. Remember, being the fire alarm expert on the job means you have to become familiar enough with the code and its many nuances to find solutions when complications arise. This ability means the customer will see YOU as the problem solver, and will trust in and rely on you when more fire alarm work is needed.