In ducts with an installed damper, a smoke detector must be placed within how many feet of the damper?

The correct choice is based on industry standards for ensuring safety in HVAC systems. In ducts that have an installed damper, placing a smoke detector within 5 feet of the damper is important for timely detection of smoke and fire. This proximity allows the smoke detector to effectively monitor the airflow in the ductwork, identifying any potential smoke that could indicate a fire.

The requirement emphasizes the need for smoke detectors to be positioned close enough to capture smoke entering the duct system while also ensuring that it remains functional and not obstructed by the damper mechanism. Being within this specific distance maximizes the safety and responsiveness of the smoke detection system, thereby helping to mitigate risks associated with HVAC-related fires.