The type of sprinkler system that contains a deluge valve, fire detection devices, and closed sprinkler heads is called a:

The correct answer is a preaction system. A preaction system is designed to enhance the fire protection capabilities of a facility by combining elements of both wet and dry sprinkler systems. This system features closed sprinkler heads, meaning they remain inactive until the system is activated by fire detection devices, such as smoke detectors or heat sensors.

The deluge valve plays a crucial role in this system; it holds back the water supply until the fire detection system recognizes a fire. Once a fire is confirmed, the deluge valve opens, allowing water into the system and activating the sprinkler heads. This delay helps minimize water damage in the event of a false alarm, as water is only released when there is a clear indication of a fire. The preaction system is particularly effective in environments where water-related damage could be a significant concern, such as data centers or museums.

This system is distinct from a wet pipe system, which has water constantly in the pipes, and a dry pipe system, where pipes are filled with air until heat from a fire causes a valve to open and water flows in. A deluge system, on the other hand, typically has open sprinklers and is used in areas where fast water coverage is needed, such as flammable liquid storage.