When should the Class A foam system be turned off during firefighting?

The appropriate time to turn off the Class A foam system during firefighting is at the start of mop-up operations. During the initial firefighting efforts, Class A foam is effective in controlling and extinguishing the fire by creating a blanket that suppresses flammable vapors and enhances water penetration. However, once the fire is deemed under control and mop-up operations begin, the primary focus shifts to ensuring that all embers and hot spots are extinguished, which can be more effectively managed with water alone or other means rather than the application of foam. This transition allows for better visibility and tracking of any remaining hot spots that could reignite, making it safe to discontinue foam use at that point.