For open deluge systems, the concentration shall be verified by flow tests at which discharge demand?

For open deluge systems, the concentration shall be verified by flow tests at which discharge demand?

• A. The midrange design flow rate
• B. The maximum system demand
• C. The actual calculated discharge demand
• D. The minimum design flow rate

Answer: (C)

For open deluge foam-water systems, verifying the foam concentration is tied to the actual discharge conditions the system is designed to meet. The concentration must be correct under the real flow rate the system would deliver when activated, not under an arbitrary or extreme rate. The actual calculated discharge demand represents the true flow rate derived from the hydraulic design for the intended fire condition, taking into account how many zones could discharge simultaneously and the network of piping and orifices. Testing at this calculated demand confirms that the proportioning device and the foam concentrate makeup can deliver the correct ratio across the system under realistic operation. Choosing other flow points—such as a midrange, maximum possible, or minimum design rate—would not necessarily reflect the conditions the system is designed for and could miss deviations in concentration under the intended discharge scenario. So, the concentration is verified by flow tests at the actual calculated discharge demand to ensure proper proportioning when the system operates as designed.

For open deluge foam-water systems, verifying the foam concentration is tied to the actual discharge conditions the system is designed to meet. The concentration must be correct under the real flow rate the system would deliver when activated, not under an arbitrary or extreme rate. The actual calculated discharge demand represents the true flow rate derived from the hydraulic design for the intended fire condition, taking into account how many zones could discharge simultaneously and the network of piping and orifices.

Testing at this calculated demand confirms that the proportioning device and the foam concentrate makeup can deliver the correct ratio across the system under realistic operation. Choosing other flow points—such as a midrange, maximum possible, or minimum design rate—would not necessarily reflect the conditions the system is designed for and could miss deviations in concentration under the intended discharge scenario.

So, the concentration is verified by flow tests at the actual calculated discharge demand to ensure proper proportioning when the system operates as designed.