Which type of system is typically used for detecting fires in large open areas?

The projected beam system is specifically designed for detecting fires in large open areas due to its unique operational mechanism. This type of system uses a light beam—either infrared or laser—that can span large distances and is particularly effective in spaces where traditional point detectors may be less reliable, such as warehouses, gymnasiums, or manufacturing facilities.

When smoke enters the beam's path, it disrupts the light transmission, triggering an alarm. This method allows for an extensive coverage area with fewer devices compared to traditional systems, making it both efficient and cost-effective for large spaces. Moreover, projected beam systems can be easily adjusted for sensitivity, accommodating various environments and minimizing false alarms caused by dust or other particulates.

In contrast, the other systems like conventional alarm systems are typically more suited for smaller, defined spaces with multiple individual detectors connected to a single control panel. Intelligent and addressable systems are advanced technologies that offer better pinpointing of detected alarms but may not be as practical for expansive, open areas where installation of many devices would be required to achieve sufficient coverage.