Which of thefollowing is not a type of automatic fire extinguishing system?

The selection of portable extinguisher systems as the answer is correct because these systems are not classified as automatic fire extinguishing systems. Automatic fire extinguishing systems are designed to activate and suppress fires without human intervention, typically using mechanisms that respond to heat, smoke, or flames.

In contrast, portable extinguishers require manual operation by a trained individual to be effective. They are intended for quick response to small fires, whereas automatic systems are integrated into buildings and designed to activate independently when certain criteria are met.

Water-based systems, wet chemical systems, and clean agent systems are all considered automatic because they automatically release extinguishing agents to control or extinguish a fire once a certain threshold is reached. These systems are crucial in providing a reliable and immediate response to fire hazards in various environments, thus ensuring safety and minimizing damage.