Fire alarm doesn't go off until the morning after a fire

We have always thought the fire alarm in our school was strange. We have a 2-story open-concept school with the 2nd story being that of a mezzanine. There is a large industrial vent above the cafeteria where the kitchen is located that has built-in fire suppression system for the kitchen. We do fire drills here and there but the fire alarm never goes off in these drills. <br><br>One time, there was a fire in the kitchen. Now, I don't know if the fire was severe or not, but the built-in fire suppression system in the vent did not kick in. The kids in the cafeteria saw the fire and ran to inform staff about the fire. <br><br>I was on the 2nd floor doing work in the staff room with another teacher. A kid came running in and was clearly distraught over something but was babbling that there was a fire. Me and the other teacher were confused but then we heard the fire alarm, which sounded super strange because we had never heard it before. <br><br>The next morning, the fire department comes to the school and investigates the scene. Apparently the fire suppression system in the vent did not kick in because it was super faulty. They found smoke residue from the fire all in the restaurant. There was enough smoke for the fire alarm to be triggered, but only the morning after. Turns out the fire alarm system that the school uses is super faulty as well and they have to inform the school administration that it's super faulty and needs to be replaced. <br><br>We've been in our new school for about 10 years and we're still learning about our fire alarms super slowly.<br><br>EDIT: Wow, thanks for all the upvotes and comments. I'm unsure of what exactly is wrong with our fire alarm system, but it seems like it's a system-wide problem for our school district. Many people have commented that they also have faulty fire alarms in their own school, even in other countries. It's absurd that we even have to worry about this but it's good to know that many people are also worried and on top of the issue.