Which system can be shut off 1 hour after ignition when used in connection with automatic sprinklers?

Which system can be shut off 1 hour after ignition when used in connection with automatic sprinklers?

• A. Dry pipe system
• B. Wet pipe system
• C. High-expansion foam system
• D. Deluge system

Answer: (C)

The capability to shut off the foam portion after ignition is a feature associated with foam-water systems, specifically high-expansion foam systems used with automatic sprinklers. These systems inject foam concentrate into the water to create a large, rapid blanket that helps control hydrocarbon fires in large or enclosed spaces. After the fire is under control and the foam blanket has done its job, the foam generation can be stopped—often on a roughly one-hour timer—while water supply to the sprinklers can continue as needed. This timed shutoff helps conserve foam concentrate and reduce long-term foam buildup. In contrast, wet pipe, dry pipe, and deluge systems are primarily water-based sprinkler systems without an integrated timed shutoff for foam generation. They deliver water (or water to all heads in the case of a deluge) and do not include a built-in mechanism to stop foam production after a set period.

The capability to shut off the foam portion after ignition is a feature associated with foam-water systems, specifically high-expansion foam systems used with automatic sprinklers. These systems inject foam concentrate into the water to create a large, rapid blanket that helps control hydrocarbon fires in large or enclosed spaces. After the fire is under control and the foam blanket has done its job, the foam generation can be stopped—often on a roughly one-hour timer—while water supply to the sprinklers can continue as needed. This timed shutoff helps conserve foam concentrate and reduce long-term foam buildup.

In contrast, wet pipe, dry pipe, and deluge systems are primarily water-based sprinkler systems without an integrated timed shutoff for foam generation. They deliver water (or water to all heads in the case of a deluge) and do not include a built-in mechanism to stop foam production after a set period.