What is NOT a prerequisite for a pre-action fire system?

In a pre-action fire suppression system, the primary goal is to prevent unintended activations while ensuring timely response during an actual fire event. A pre-action system typically relies on both smoke and heat detection elements to identify a fire's presence before the water is released into the piping system.

While manual activation can be a component of some fire suppression systems, it is not considered a prerequisite for a pre-action fire system. This type of system is designed to allow automated detection to trigger activation without necessitating a manual intervention. The activation relies mainly on the detected conditions—either smoke or heat—rather than requiring manual activation by a person.

By having smoke and heat detection components, the system ensures a higher level of protection, as it can differentiate between false alarms and real fires more effectively. Therefore, the absence of manual activation as a prerequisite aligns with the system's operational design, making it the correct choice in this context.