What characteristics determine the spacing of combination notification appliances attached to a fire alarm and signaling system?

The spacing of combination notification appliances in a fire alarm and signaling system is primarily determined by visual characteristics. This involves understanding how effectively a visual alarm, such as a strobe light, can be seen within a given space. Factors that influence this include the brightness of the light, the color, and the range at which it can be seen clearly by occupants.

Visual notification appliances must be installed in a manner that ensures all areas within a building are adequately covered, especially in spaces where the auditory alarms may not be sufficient due to high ambient noise levels or for individuals who are hearing impaired. Adherence to standards such as those outlined in the National Fire Protection Association (NFPA) guidelines helps ensure that the visual alerts provide the required coverage and effectiveness in alerting occupants to evacuate safely.

In contrast, the other characteristics such as audible cues refer to sounds produced by alarms, textual refers to written communication (which is not typically part of the alarm system), and distance from exits is more related to overall building safety and egress planning rather than directly impacting the spacing of notification appliances. Thus, visual characteristics take precedence in determining the proper installation and spacing of combination notification appliances in fire alarm systems.