Editor’s Note: This is the fourth and final phase of Ben Adams’s sample fire alarm installation. To read each of the first three parts of the series, please visit www.securityinfowatch.com/53073292.
Local amendments matter. Relying solely on the base versions of the International Fire Code (IFC) or International Building Code (IBC) can leave your project painfully under-scoped. If your estimate or system design doesn’t account for regional adaptations, you could get stuck with unplanned cost, complexity, and integration requirements.
Such is the case for three aspects of our sample fire alarm installation:
Defining a High-Rise
When we first began stepping through the fire alarm requirements for a hypothetical building in Plano, Texas, in my January column, we immediately came across a requirement for building occupant notification.
The requirements for notification appliances are repeated under several different occupancy classifications; however, the relevant sections in IFC 907.2 do not specify whether we could use simple horns or if we need speakers and amplifiers. While the code defaults to horns and strobes, IFC 907.2.13 requires an emergency voice/alarm communication (EVAC) system for high-rise buildings – which means we would need speakers and strobes.
To decide which, we need to determine whether our building is a high-rise.
High-rise buildings are defined in IBC Section 202. The threshold is 75 feet (23 m) above the lowest level of fire department access (so basically, 75 feet above the ground). Any shorter than that and the building is not a high-rise.
Everywhere I have worked, this 75-foot rule has been applied to the floor – the literal floor you stand on. The building could be 100 feet (30.5 m) tall, but if the top floor is 26 feet (8 m) from the floor to the roof, making the floor of the top story only 74 feet (22.5 m) above the ground – then it wouldn’t be classified as a high-rise.
This logic is based on how high the fire department’s aerial ladders can reach. As long as they reach the bottom of the top floor, firefighters can access that floor. Above that, there is a greater risk to occupants, and thus, more strict requirements – like voice evacuation – are needed.
Our building is only 59 feet (18 m) to the floor of the top story, so we can use horns, right? Nope! The City of Plano adopted the 2021 IFC with amendments, which lowered the high-rise threshold to 55 feet (17 m) due to the reach limit of their ladders (this is common for smaller cities that lack big ladder trucks). That means our building now qualifies as a high-rise, and voice evacuation per IFC 907.5.2.2 will be required.
Wiring Regulations
Many jurisdictions have concerns about the vulnerability of fire alarm circuits. Traditional Class B initiating device and notification appliance circuits terminate at an end-of-line resistor so the panel can supervise the integrity of the wire. As long as a small amount of current is flowing, the circuit is interpreted as “normal.” Signaling line circuits are supervised via communication with each addressable device.
If a device is removed from a Class B circuit without rejoining the wires or if a wire is cut, all the devices downstream are impaired.
Class A circuits step this up with redundancy. Afeeter the wire is run to all the devices, it is routed back to the panel. This Class A return allows the panel to treat the circuit as two separate circuits if there is ever a wire break. It’s an easy and affordable way to make the building’s life safety system much more resilient.
That’s why you ofeeten see changes like Plano’s amendment to IFC 907.6.1.1, which requires initiating device and signaling line circuits (IDC and SLC) to be installed in a Class A configuration. Note that notification appliance circuits (NACs) are not included in this requirement.
Plano’s amendment further specifies that there must be 4 feet (1.2 m) horizontally and one foot (30 cm) vertically between outgoing and return wiring. This is to reduce the likelihood that whatever event caused an open circuit on one wire doesn’t simultaneously do so on the return wires.
Class A wiring increases the amount of wire you need to include in your estimate and the time needed to install it. It also potentially requires three separate risers on each floor: one for the wire coming up from below, a second one for the wire going up to the next floor, and a third one for the home run back to the panel.
Let’s look at one more local amendment that could have come into play with our example building.
Special Requirements for Assembly
When reading the January 2025 issue, you might have been surprised to find that restaurants are considered assembly areas. Most people typically think of Group A as being theaters, churches, and sporting or concert venues. It turns out that there can be special requirements for those buildings.
Plano’s amendment to the rules for Group A Assembly occupancies in IFC 907.2.1 requires us to illuminate the exit pathway and stop any confusing or conflicting audio/visual distractions.
If the Group A portion of our building had included a church or theater, we would have needed to turn off the sound system and video projectors and turn up the lights when the fire alarm is activated.
