What role does eutectic salt play in the Fenwal continuous loop fire detection system?

The eutectic salt in the Fenwal continuous loop fire detection system is pivotal because it plays a crucial role in sensing temperature changes indicative of a potential fire. When temperatures rise due to a fire, the eutectic salt undergoes a phase change that alters its physical properties. This change is primarily in its resistance to electrical currents. As the salt melts and transitions from solid to liquid, it effectively changes the overall resistance of the sensing element within the loop. This change in resistance is then detected by the system, which activates the alarm or response mechanisms to alert for the presence of a fire.

While other options mention cooling, electrical conduction, or extinguishing fires, they do not accurately reflect the primary function of the eutectic salt in a fire detection context. The critical aspect of this system is its ability to detect early signs of overheating through the alteration of resistance, making the option about changing resistance the most relevant and accurate in explaining the role of eutectic salt.