How far below the finished ceiling should wall-mounted audible signal appliances be installed?

Wall-mounted audible signal appliances should be installed a minimum of 6 inches below the finished ceiling to ensure proper sound coverage and effective operation. This height helps to maximize the sound distribution pattern of the appliance, allowing it to be heard clearly throughout the intended area. Installing the devices too close to the ceiling may reduce their effective reach, leading to reduced audibility in the space they are meant to serve.

The 6-inch guideline is established in the National Fire Alarm and Signaling Code, which aims to standardize fire alarm system installations and optimize their performance for safety and compliance.