Why is CI Cable Required by Code?

A lot of fire alarm salesman and installers are probably wondering why CI cable is required. 

On March 12, 1984, a fire started within a retirement home in the City of Delaware, Ohio.  Smoke detectors located withing the common area sensed the fire and activated the NACS (notification appliance circuits (NAC Voltage Drop Calculations).  However, the fire quickly engulfed the surface mounted metal raceways and damaged the internal circuits.  The damage was so severe that it disabled the notification devices from sounding.  Due to the rapid silencing of the fire alarm system, some of the residents believed the signals to be false and did not evacuate.  By the time the residents learned the a the fire was in fact real it had grown large large enough to block their exits.  Two of these residents died - one from smoke inhalation and the other had a heart attack.  On top of that 7 others where injured.

In order for the fire department to properly evacuate a building they need the fire alarm system to operate through the emergency.  At least long enough for the occupants to reach safety.  In some case total evacuation is not necessary and could cause more harm than good.  This is the reason for voice evacuation and mass notification systems.  For more information on Mass Notification and Voice Evacuation read on the Notifier Onyx Series Fire Alarm Systems.

With CI cable you can be assured that the circuits have a 2 hour window of survivability.  This in most cases will be enough time to warn the occupants and respond accordingly.

What is CI Cable?