What is a primary disadvantage of heat detectors?

The primary disadvantage of heat detectors is that they do not provide reliable life-safety protection. This is because heat detectors are designed to react to the presence of heat, typically at a certain threshold, which means that they may not detect smoldering fires or fires that are at very early stages—fires that might emit smoke before generating significant heat. As a result, there is a critical window in which occupants could be exposed to smoke and toxic gases without any warning before a heat detector activates. This limitation can significantly impede the effectiveness of heat detectors in ensuring the safety of occupants during a fire event.

In comparison, while false alarms can indeed be a concern with some types of detectors, heat detectors are generally less prone to false alarms when compared to other detection systems such as smoke detectors, which can be triggered by steam, cooking fumes, or other non-fire-related phenomena. Cost considerations related to installation also do not directly correlate with their effectiveness in terms of life safety. Therefore, while heat detectors serve an important role in fire detection, their limitations in providing timely alerts to early-stage fires render them less reliable for safeguarding lives in fire scenarios.