What type of sprinkler system utilizes a pressurized tank to store water?

A wet pipe system is designed to store water in a pressurized tank and maintain it within the sprinkler piping. This type of system comprises pipes filled with water that is discharged directly to the sprinkler heads when activated by heat, without delay. The pressurized tank ensures that water is readily available at the sprinkler heads at all times, allowing for a quick response in the event of a fire. This system is commonly used in areas where the temperature does not drop below freezing, as it can be effective and efficient in fire suppression.

The other options refer to different systems that do not utilize a pressurized tank to store water. A dry pipe system, for example, contains pressurized air or nitrogen in the pipes. Water only flows into the system when a fire causes the dry pipe valve to open. Similarly, a pre-action system is a combination of wet and dry pipe systems, where water fills the piping only after an initial detection of fire through a smoke or heat detector. Thus, the defining characteristic of a wet pipe system, where water is stored and maintained under pressure, is what makes it the correct choice.