Article by Matt Karver – Fire Alarm System Specialist –

Circuit Integrity cable (or CI cable) is a cable that can withstand a direct fire attack for two continuous hours before failing to function.  CI cable is significantly more expensive than other cabling systems for your fire alarm system, so it is important to understand your building or project’s fire rating, as well as your state and/or locally adopted code requirements.

When determining when to use CI cable, we need to understand the different levels of pathway survivability.  As a disclaimer, this article does not factor in the code changes for pathway survivability in the NFPA-72 2022 edition, because it has not been adopted yet in Pennsylvania or New Jersey. 

4 Levels of Pathway Survivability

There are currently four different levels of pathway survivability – Level 0, Level 1, Level 2, and Level 3.  The requirements for each level are as follows in Section 12.4:

Pathway Survivability Level 0:

Level 0 pathways shall not be required to have any provisions for pathway survivability

Pathway Survivability Level 1:

Pathway survivability Level 1 shall consist of pathways in buildings that are fully protected by an automatic sprinkler system in accordance with NFPA 13 with any interconnection conductors, cables, or other physical pathways installed in metal raceways.

Pathway Survivability Level 2:

Pathway Survivability Level 2 shall consist of one or more of the following:

• 2-hour fire-rated circuit integrity (CI) or fire-resistive cable
• 2-hour fire-rated cable system [electrical circuit protective system(s)[
• 2-hour fire-rated enclosure or protected area
• Performance alternatives approved by the authority having jurisdiction

Pathway Survivability Level 3:

Pathway survivability Level 3 shall consist of pathways in buildings that are fully protected by an automatic sprinkler system in accordance with NFPA-13 and one or more of the following:

• 2-hour fire-rated circuit integrity (CI) or fire-resistive cable
• 2-hour fire-rated cable system [electrical circuit protective system(s)[
• 2-hour fire-rated enclosure or protected area
• Performance alternatives approved by the authority having jurisdiction

For fire alarm systems specifically, pathway survivability levels 2 and 3 are required for In-Building Fire Emergency Voice/Alarm Communication Systems that employ occupant relocation or partial evacuation.  For example, if a high-rise building does not want to evacuate the entire building simultaneously to avoid dangerous bottlenecking, the building can evacuate areas of the building that are closest to the life-threatening situation, then evacuate the remainder of the building in stages.  A partial evacuation or relocation would require the emergency communication system to function for a longer period of time, thus requiring the cabling feeding that system to survive longer durations of fire attack. 

The cables that are critical to the operation of notification appliances are to be protected until they reach the notification zone that they serve.  The system should also be designed such that a fire attack within a notification zone should not affect the operation of notification appliances outside of that zone.  If a piece of control equipment is reliant upon another piece of control equipment in another section of the building, the wiring connecting the control equipment shall be protected by Level 2 or 3 survivability. 

A practical application of CI cable would be a notification appliance circuit that needs to travel from the 1^st floor to the 5^th floor.  Its journey begins at the fire alarm control unit where it travels 50’ down the 1^st floor unprotected corridor to a 2-hour fire rated stair tower, up the stair tower, and out to the 5^th floor notification zone.  The only section of this circuit that requires CI cable is the 50’ it travels from the fire alarm control unit to the 2-hour rated stair tower on the 1^st floor.  While the wire traverses up the stair tower, it meets option #3 of pathway survivability Level 2, “2-hour fire rated enclosure or protected area,” and does not require CI cable.

When planning a project, it is crucial to coordinate with the project design team and the contractor who will be installing the cabling, so that the fire alarm system can function reliably during life-threatening situation and efficiently execute the evacuation plan.