I was motivated by firefreak57 making a topic about how the fire alarm systems in his schools and district changed over time to do the same thing after taking a look at the years my elementary school was around for and figuring out which upgrades it would have been installed with at different periods over the years. I have no proof to back any of these or the years up but this is what I would BELIEVE have happened over the years after the school was built in 1918. So without further ado, lets go.
1918 to 1954 - The original system was just one bell on each floor connected to a pull rod that would be pulled to alert the occupants that a fire started in the building.
1955 to 1975 - When the school upgraded to an automated electric fire alarm system, the bells and the pull rods were removed along with any other remnants and the school had IBM 4030 horns put in.
1976 to 1991 - The school had its alarms once again upgraded when Simplex finally had started using alarms of their own rather than using alarms from another company. This time they were Simplex 4051 horns on 4050-80 light plates. The other schools in the district also at one point had these alarms so its more than likely this school had them also.
1992 to 1994 - A new cafeteria was built and the alarms that were used in the installation were Simplex 2901-9838 horns on Simplex 4903-9101 strobe plates. This included an entryway outside the cafeteria. The old cafeteria was converted to a classroom wing and the 4051s+4050-80s there were replaced with the 4903s+9838s. 4051s+4050-80s in the elevator room and in the storage and boiler room were also replaced as they had died. The rest of the 4051s+4050-80s remained untouched.
1994 - Two 4051s+4050-80s in two back rooms ended up breaking down so they were then replaced by Gentex SHG horn/strobes after it was discovered the horns died. One classroom was what would become the dual art/music room when I was there (and the first time I heard it) before becoming an ESL classroom and the other room was a self-contained classroom for grades 4 to 6 before becoming a reading room and then the speech and psychologist’s room.
1995 - The 4903+9838 that was in the classroom that used to be the former cafeteria kitchen stopped working and was replaced with a vertical Wheelock AS set to code-3. This room was a first grade classroom before becoming a multipurpose room and now it is a music room.
1995 to 2012 - All of the remaining 4051s+4050-80s were replaced with Simplex 4903-9219 horn/strobes as well as a lone 4903+9838 combo in a basement hallway while all of the other horns that were installed during the time the school was using the 4051s+4050-80s remained in the school.
1995 - All of the bathrooms except the two in the cafeteria received Simplex 4904-9137 remote strobes within them that would flash during an alarm in case the alarm couldn’t be heard outside.
2013 to 2017 - The whole system including all of the devices as well as the pull stations were replaced with a Notifier system and SpectrAlert Advanced speaker/strobes were what was used as the notification appliances.
2018 - The school is currently being renovated right now and it is holding classes in the Pawtucket Annex. If the system is replaced again, I would assume it would have System Sensor L speaker/strobes.