Why Fire Alarm & Fire Sprinkler Systems Are Not the Same

Announcement
Hear ye, here ye! Fire alarms and fire sprinklers are two different systems. They work together and are very closely related but they are not the same thing. They require different contractor licensing and are guided by separate codes and standards:

NFPA 72: National Fire Alarm and Signaling Code
NFPA 13: Standard for the Installation of Sprinkler Systems

Fire alarm systems are widely misunderstood because they do so much. In addition to the normal smoke detector, heat detector, and pull station functionality fire alarm systems can monitor other major building systems. The most commonly monitored auxiliary systems are HVAC and fire sprinkler, but you can monitor just about anything; fire curtains, pool pumps, panic buttons.

Karate Kid?
I know that some of the confusion is created by and spread through the entertainment industry. Karate Kid is a good example, the original 1984 movie not the 2010 remake. Daniel burns a piece of paper under a sprinkler head and sets off the system. When one sprinkler head pops and begins to spray water it does not force all of the other sprinkler heads in the building to go off as well.

I watched an episode of Parks and Recreation where Leslie Knope pulls a fire alarm pull station and the sprinkler heads all pop and spray everyone in the room. That’s not really how it works but if you don’t know any better you may see that show and think you’ve learned something.

What Really Happens
When you pull a fire alarm pull station it sets off the alarm to let everyone know that there is a fire in the building and they need to get out. Remember fire alarm drills in school? When you hear a fire alarm you stop what you are doing and calmly evacuate the building.

The only time a fire sprinkler head will spray water is when heat has popped the glass bulb. The glass is designed to break at a designated temperature but they will also spray if they are physically damaged. It has happened on occasion that someone accidentally hits a head and breaks it.

The Three Signals: Alarm, Trouble, Supervisory

  • Alarm signals set off the alarm in the building for the purpose of immediate evacuation.
  • Trouble signals indicate a service issue present on the system such as a bad smoke detector or cable.
    For example: The intern pushes a mail cart down the hallway and knocks a pull station off of the wall. The pull station gets smashed into tiny pieces and the fire alarm cables are dangling from the wall. The fire alarm system will show that there is a trouble with that particular pull station and the rest of the system will continue to operate as usual.
  • Supervisory signals announce that a very important component has been tampered with.
    For example: The fire alarm system monitors the fire sprinkler system main valve. If the main valve is closed to prevent water from flowing into the fire sprinkler system that is a very important event to be aware of. If the valve is closed and the building catches on fire the water will not flow.

The lesson is that not every signal, beep, sound, or light on a fire alarm system is an alarm. More specifically, not every signal originates from the fire alarm system itself. Read the description of the event on the panel, it could be a fire sprinkler system issue.

When was the last time you had a fire drill?