A fire alarm system that detects a fire but never tells anyone about it isn’t much use. Notification appliances, the horns, strobes, and speakers that alert occupants, are governed by specific requirements under NFPA 72 that go beyond simply installing a device on the wall.
Audible and Visible Requirements
NFPA 72 sets minimum sound levels for audible notification (typically a set decibel level above ambient noise) and requires visible notification, strobes, in spaces where the Americans with Disabilities Act requires accommodation for people who are deaf or hard of hearing, which in practice means most commercial occupancies.
Spacing and Placement Rules
Strobes and horns aren’t placed arbitrarily; NFPA 72 includes spacing tables based on room size and ceiling height to make sure notification is effective throughout a space, not just near the device itself.
Voice Evacuation Systems
Larger or more complex commercial buildings, especially high-rises and healthcare facilities, often use voice evacuation systems instead of (or alongside) horns and strobes, providing spoken instructions that can be customized by zone, useful for phased evacuation in a large building.
These requirements are why fire alarm design is its own specialty within fire protection engineering. See our full guide to Commercial Fire Alarm & Detection Systems.