What is a preprimed system?

• A. Wet pipe system containing foam solution
• B. Wet pipe system with water only
• C. Dry pipe system
• D. Deluge system with foam

Answer: (A)

A preprimed system means the foam concentrate is already in the piping before any activation, so the system is ready to discharge foam immediately when water flows. In a foam‑water sprinkler setup, having the piping filled with foam solution (a wet pipe configuration) ensures that the discharged stream is foam from the first moment of operation, without waiting for foam to be inducted into the water. This is why a wet pipe system containing foam solution best fits the idea of preprimed. Other options describe systems that either carry only water, use a dry pipe arrangement, or rely on foam being added later to the water stream, none of which are preprimed.