Understanding NEC Rules: A Guide for Electrical Engineers

Introduction A Notification Appliance is any device that alerts building occupants of a fire or emergency through audible, visible, or tactile signals . These appliances are essential components of fire alarm systems, ensuring timely evacuation and awareness in emergencies. Types of Notification Appliances 1. Audible Notification Appliances Common types: Horns, Bells, Speakers, and Buzzers. Evacuation signal pattern: Temporal Three (T3) – three half-second pulses followed by a 1.5-second pause. For sleeping areas: low-frequency sound 520 Hz ±10% is required to awaken sleeping occupants. Sound level must be at least 15 dB above ambient noise or 5 dB above the maximum sound lasting 60 seconds. 2. Visible Notification Appliances (Strobes) Provide flashing light for hearing-impaired occupants. Light intensity measured in candela (cd) per room size and height. Mounting height: 80–96 inches (2.03–2.44 m) above floor. Multiple strobes must be synchronized to prevent ...