Notification appliances are devices within fire alarm systems designed to alert building occupants of a fire emergency. These appliances include audible devices such as horns, bells, and sirens, and visual devices such as strobe lights. They play a critical role in ensuring that occupants are quickly and effectively alerted to evacuate the building or take other appropriate actions.

The design and placement of notification appliances must comply with Chapter 18 in NFPA 72, which provides guidelines on the audibility and visibility requirements for different types of buildings and occupancy types. Audible alarms must be loud enough to be heard over background noise, but not so loud as to cause hearing damage. Visual alarms must be bright enough to attract attention, even in well-lit areas.

Proper circuit design is also crucial for the effective operation of notification appliances. Circuits must be designed to ensure that all devices receive adequate power and can operate simultaneously without causing voltage drops or overloads. This often involves calculating the total current draw of all devices on a circuit and ensuring the wiring and power supply can handle the load. Proper circuit design ensures that all devices receive adequate power without causing voltage drops or overloads. Inadequate power for notification appliances can lead to malfunctioning devices, which might trigger false alarms.

Notification appliances should be placed strategically to ensure that the alarm signals can be perceived by all occupants. This includes placing audible devices in hallways, common areas, and rooms where people might be present, and ensuring visual devices are visible from all parts of a room. In areas with high ambient noise levels, such as manufacturing facilities, visual alarms may be more effective, and in sleeping areas, combination alarms with both audible and visual signals might be required.

Regular testing and maintenance of notification appliances are essential to ensure they function correctly during an emergency. This includes checking that audible alarms are producing the correct sound levels and that visual alarms are flashing at the required intensity and frequency. By ensuring proper design, placement, and maintenance of notification appliances, installers can enhance the safety and effectiveness of fire alarm systems.