The fire alarm power supply according to NFPA 110 plays a critical role in ensuring the safety and reliability of fire alarm systems during power outages.

According to the NFPA 110 Standard for Emergency and Standby Power Systems, all fire alarm systems must include both a primary and a secondary power source.

The secondary source serves as a critical backup during power outages, ensuring the alarm system continues to operate when electricity fails.

Power outages are inevitable—whether caused by weather events, equipment failure, or planned work. That’s why it’s essential to understand your facility’s backup options and maintain compliance with fire safety codes. Fortunately, the flexibility of current codes allows for several compliant power supply solutions.

Fire alarm systems usually draw power from the electric grid, but alternatives can also be used to meet NFPA 110 requirements. Let’s take a closer look at the common options:

• Stored-Energy Emergency Power Supply Systems (SEPSS): These uninterruptible power supplies offer stored energy as a backup and can serve as both primary and secondary sources.

• Engine-Driven Generators: These generators convert mechanical energy into electricity and are commonly used in large buildings.

• Cogeneration Systems: An energy-efficient system that produces both electrical and thermal energy from a single fuel source.

• Electric Grid: The most traditional method, connected to local utilities and widely used in residential and commercial setups.

A secondary power source is not optional—it’s lifesaving. Fire alarm systems are considered Level 1 systems under the NFPA, meaning that failure could directly endanger human life. Without backup power, crucial alerts and emergency systems will not activate during an outage.

Events like inclement weather, construction mishaps, or utility failures can trigger blackouts. In these situations, your backup system is what keeps your building safe and code-compliant.

To meet NFPA 72 and NFPA 110 standards, your secondary power supply must be able to:

• Support the system in standby mode for 24 hours, and

• Operate for at least 15 minutes under load when an alarm is triggered.

Even if your building uses an emergency generator, you still need backup batteries to remain compliant. In this case, batteries must power the fire alarm system for a minimum of 4 hours. This gives you enough time to fix or troubleshoot generator issues during a real emergency.

Sealed lead-acid (SLA) batteries are the most common choice. They’re low-risk, dependable, and usually installed within the control panel or in a dedicated battery box nearby.

Proper maintenance ensures your power systems stay reliable and compliant. Your fire alarm control panel can monitor battery voltage and alert you with a trouble signal or audible warning when it’s time for a replacement.

Maintenance tips include:

• Replace batteries every three years or perform a load test.

• Conduct weekly generator starts and checks for life-saving systems.

• Keep detailed service records for all inspections and tests.

• Follow the manufacturer’s guidelines and local code requirements.

Choosing and maintaining the right fire alarm power supply system isn’t just about meeting code—it’s about protecting lives. Whether you rely on SEPSS, generators, or backup batteries, ensuring your system is tested and maintained regularly is crucial.

Need help designing a compliant and reliable fire alarm power supply system? Reach out to our certified fire safety experts today.

• Have all maintenance performed by qualified professionals.

The NFPA 110 outlines the required procedures for installation, testing, and servicing of these systems. Routine maintenance is not just best practice—it’s essential for safety and legal compliance.