The fire alarm system in the Marshall Simonds Middle School is based on a Notifier Onyx fire alarm panel. It is a voice evacuation system. This means that instead of a sound produced through horns throughout a building, the panel sends information to fire alarm speakers.
System Sensor SPSR
Notifier ONYX Fire Alarm Panel
The speakers (combined with strobes) in this building are the System Sensor SPSR. This is good because it tells the occupants specific directions and information, instead of a generic-sounding horn or bell which could mean pretty much anything.
Responders can also use the microphone in the panel to announce live information mid-emergency to occupants throughout the building such as “The staircase at the end of B Corridor by the Art Rooms is flooded with smoke and toxic gases and should be avoided.” This would be very difficult to announce with a traditional alarm system, as the speakers normally used for announcements would likely be destroyed or have no power, and the system would be incapable of anything but make noise. People in the school would go to these places, thinking they were safe (there is an exit sign), and be put in more danger.
Thank you Josh for this information!