Which method is NOT a way to activate a deluge system?

A deluge system is designed to deliver large volumes of water to areas at risk of fire. The correct answer is related to understanding how deluge systems are typically activated.

Manual activation involves physically operating a valve or a switch to trigger the system, which is a standard practice in emergency situations. Smoke detector activation is another valid method, where the system is set off by detecting smoke, signaling a potential fire. Additionally, a pressure drop in a pilot line system can indicate the presence of a fire, prompting the deluge system to activate.

Turning off the main water supply does not activate a deluge system. In fact, it would prevent the system from functioning, as there would be no water available to suppress a fire. The primary goal is to facilitate the flow of water when a fire is detected or manually triggered, making the deactivation of the water supply contrary to the purpose of the system.