A wet pipe system containing a foam solution is known as a:

• A. Wet foam system
• B. Deluge foam system
• C. Pre-primed foam system
• D. Dry pipe foam system

Answer: (C)

When foam is used in a fire protection system, priming refers to having the foam concentrate mixed with water in the piping before discharge. A wet pipe system that already contains the foam solution in its filled pipes is designed to deliver foam immediately when a head is activated. This arrangement is called a pre-primed foam system. It ensures the foam solution is ready to go without a separate priming step at discharge.

The other options don’t fit the scenario as well: a deluge foam system has all piping outlets open and releases foam through every head, which isn’t implied here; a dry pipe foam system has piping filled with pressurized air or inert gas and water (and foam) enters the system after the valve opens; and a general wet foam system isn’t the specific term for foam that’s already in the lines as foam solution.