What type of detection system is often included as a backup in fire-extinguishing systems?

The correct choice is the automatic mechanical detection system. This type of detection system is designed to operate autonomously, activating the fire-extinguishing system without the need for human intervention. Its role as a backup is crucial because it ensures that the extinguishing agent is deployed promptly in the event of a fire, even if other detection methods fail or are delayed.

Automatic mechanical detection systems typically use temperature-sensitive elements that respond to heat from a fire. When the temperature reaches a predetermined level, the system activates the fire-extinguishing agent, providing reliable and timely response to fire hazards. This makes it essential in environments where rapid fire response is critical for safety.

In contrast, pressure monitoring systems, smoke detection systems, and infrared detection systems may possess their own advantages but do not fulfill the same backup role in the context of fire extinguishing. Pressure monitoring focuses on the operational integrity of the extinguishing system rather than directly detecting fire. Smoke detection is vital, yet it requires the presence of smoke before activation can occur, which may not be immediate. Infrared detection systems can also take time to trigger based on heat radiation and may not respond as quickly as a mechanical system that is designed specifically for this purpose.