Over pressure shall not exceed the...

Over pressure shall not exceed the...

• A. The working pressure of the foam concentrate piping system.
• B. Twice the design pressure of the system.
• C. The maximum water pressure in the supply line only.
• D. The design discharge pressure.

Answer: (A)

In foam-water sprinkler systems, the foam concentrate piping is built to a specific working pressure. Overpressure must not exceed that working pressure to keep the piping and components, like fittings and valves, within their safe, rated strength. If the system were pressurized beyond this limit, the piping could deform or fail, and foam mixing and delivery could be compromised. Twice the design pressure or the maximum water pressure in the supply line are not the controlling limits for foam concentrate piping, because the critical factor is the rating of the foam piping itself, not a multiple of design pressure or the water supply alone. The design discharge pressure relates to the outlets where foam and water exit the system, not to the safe pressure for the foam piping network.

In foam-water sprinkler systems, the foam concentrate piping is built to a specific working pressure. Overpressure must not exceed that working pressure to keep the piping and components, like fittings and valves, within their safe, rated strength. If the system were pressurized beyond this limit, the piping could deform or fail, and foam mixing and delivery could be compromised.

Twice the design pressure or the maximum water pressure in the supply line are not the controlling limits for foam concentrate piping, because the critical factor is the rating of the foam piping itself, not a multiple of design pressure or the water supply alone. The design discharge pressure relates to the outlets where foam and water exit the system, not to the safe pressure for the foam piping network.