Which of the following is NOT one of the six sprinkler system types listed?

• A. Air-pressurized
• B. Wet pipe
• C. Deluge
• D. Preaction

Answer: (A)

Sprinkler system types are categorized by how water is stored and released in the piping. Wet pipe systems have water-filled pipes that deliver water to a sprinkler head immediately when it’s opened. Deluge systems keep all heads open so water is released to all heads once the system is activated. Pre-action systems require a triggering event beyond a sprinkler head to release water into the piping, adding a safeguard against accidental discharge. Air-pressurized, while it can be used within dry-pipe arrangements to maintain pressure, isn’t itself listed as a separate sprinkler system type in the common classifications. So it isn’t counted as one of the standard types, making it the option that isn’t among the six listed.