Occupant Notification Devices

Q: Is there a specific distance that fire alarm audible/visible notification appliances are required to be mounted from other similar devices? We have multiple strobe devices in some rooms, but not in others.

A: Wall-mounted audible notification appliances are required to be at least 90 inches above the floor as measured at the top of the device, but a minimum of 6 inches below the finished ceiling. If the audible notification appliance is combined with a visible notification appliance, then the mounting location of the device shall be determined by the requirements for the visible notification appliance. Wall mounted visible notification appliances shall be mounted so the entire lens is not less than 80 inches and not more than 96 inches above the finished floor. (Some exceptions for performance-based design apply). Ceiling mounted installations are permitted for occupant notification appliances provided the devices are rated by the manufacturer for such installation. If the combination audible/visible notification appliance is an integral part of the smoke detector, then the mounting location shall be determined by the requirements for the smoke detector.

The capacity of each occupant notification appliance (whether it be audible or visible) is determined by the manufacturer, and the minimum requirements found in NFPA 72. Since there are different capacities with a variety of notification appliances, the mounting locations are determined by the sound pressure ratings for audible devices, and candela ratings for visible devices. Basically, (with some limitations spelled out in the NFPA 72 standard) the manufacturer of the notification appliance makes the determination how far apart they can be installed and how many devices are required for a given room. But NFPA 72 does provide tables for minimum standards for the mounting locations of visible notification appliances, based on the intensities of the candela rating of each device.

The spacing and locations of the occupant notification devices is specified by the designing engineer for the original project, and is reviewed by the authority having jurisdiction for design and construction. Once approved, the installing contractor must mount the specified occupant notification device where the designing engineer stipulates. Once installed, the installing contractor is required to conduct a sound pressure test on the audible devices to measure the dB at the specified locations for each device to ensure the performance is in accordance with the engineer’s specifications.

To directly answer your question… Yes there are specifications on the mounting locations of these occupant notification devices, but it has to do with the manufacturer’s rating of their devices along with NFPA 72 standards.