Foam concentrate injection shall be activated automatically by, or concurrently with, activation of which component?

Foam concentrate injection shall be activated automatically by, or concurrently with, activation of which component?

• A. Foam concentrate pump
• B. Manual switch
• C. Drain valve
• D. Main water supply control valve

Answer: (D)

When foam-water sprinklers start discharging, the foam concentrate must be introduced into the water stream immediately. The most reliable way to ensure this is to have the foam concentrate injection activated automatically, or at least in step with, the opening of the main water supply control valve. Opening that valve starts the water flow through the proportioning device, which meters in the foam concentrate and mixes it with the water as it travels to the heads. This concurrent action guarantees the correct foam-to-water ratio from the moment discharge begins. Relying on a foam concentrate pump as the trigger can lead to timing issues or delays if the pump hasn’t started or isn’t powered, and a manual switch would require operator action during a fire, which is not dependable. A drain valve is not involved in delivering foam concentrate.

When foam-water sprinklers start discharging, the foam concentrate must be introduced into the water stream immediately. The most reliable way to ensure this is to have the foam concentrate injection activated automatically, or at least in step with, the opening of the main water supply control valve. Opening that valve starts the water flow through the proportioning device, which meters in the foam concentrate and mixes it with the water as it travels to the heads. This concurrent action guarantees the correct foam-to-water ratio from the moment discharge begins.

Relying on a foam concentrate pump as the trigger can lead to timing issues or delays if the pump hasn’t started or isn’t powered, and a manual switch would require operator action during a fire, which is not dependable. A drain valve is not involved in delivering foam concentrate.