What is the maximum allowable height for mounting smoke alarms on a wall?

The correct maximum allowable height for mounting smoke alarms on a wall is 12 inches from the ceiling. This height is significant because smoke rises, and placing alarms at this specified distance allows them to effectively detect smoke before it accumulates too far down from the ceiling.

Mounting smoke alarms too close to the ceiling can cause them to fail to detect smoke in its early stages. Conversely, if smoke alarms are placed too low, they may not operate efficiently, as it would take longer for smoke to reach them. Therefore, adhering to the 12-inch guideline strikes the right balance for ensuring proper functionality while considering safety standards.

Other options, while providing some reasonable heights, do not align with the national code recommendations tailored towards effective smoke detection, which is why they are not the preferred choice.