Which statement is true regarding duct detectors mounted on the air ducts of a 5,000 CFM unit?

Duct detectors are specialized smoke detectors designed for installation within air ducts and are essential for maintaining safety in environments with significant air handling. When mounted on the air ducts of a 5,000 CFM unit, several important considerations come into play regarding their usage.

Firstly, it's crucial that the smoke detectors installed in the air ducts are specifically listed for that application. This means they are tested and approved to operate effectively in the potentially challenging conditions of the air stream, which includes factors like dust, air velocity, and the temperature range typical for such environments. Therefore, the requirement that the smoke detector must be listed for use in air ducts is a fundamental safety criterion.

Secondly, duct detectors have the capability to initiate supervisory signals. This is important for monitoring the operational integrity of the air handling system. Supervisory signals can provide information about system conditions, alerting personnel to any issues that may pose a risk to safety or proper system function.

Lastly, duct detectors are also designed to initiate alarm signals when smoke is detected. This is a key function in fire safety systems as it directly contributes to the early warning capabilities essential for life safety and property protection during a fire event.

When considering all these points together, the correct answer reflects that all the statements regarding the duct