Fire alarm systems may also use visible fire alarm notification appliances. They are most often used to supplement the audible appliances, where ambient sound levels are too high to hear the audible appliances, where hearing-impaired individual may be located, or where required by other codes and standards.

Where visible notification appliances are used for public mode notification there is a minimum flash rate (1 per second) and a maximum flash rate (2 per second).

NOTE: This is an unformatted excerpt from our online fire protection training library.