Visual appliances are required in an area if the average ambient sound level is greater than what level?

Visual appliances are required in an area when the average ambient sound level exceeds 105 dBA. This requirement stems from the need to ensure that individuals with hearing impairments can effectively respond to fire alarm signals. When the ambient sound level is too high, audible alarms may not be heard, making it crucial to incorporate visual signals like strobes or flashing lights to alert all occupants of a potential emergency.

The threshold of 105 dBA is established by safety codes and standards, which aim to ensure adequate notification measures in environments where background noise can mask alarm sounds. Therefore, having visual alerts in spaces with sound levels above this threshold enhances the overall effectiveness of a fire alarm system, ensuring that all individuals, regardless of their hearing capability, can take appropriate action during an emergency.