How frequently should class B foam be reapplied to effectively seal vapors?

Reapplying class B foam every 10 to 15 minutes is considered effective for sealing vapors. This frequency is crucial for maintaining a reliable barrier against flammable vapors, ensuring that the foam remains effective under dynamic conditions, such as temperature fluctuations or disturbances from wind.

The characteristic properties of class B foam allow it to create a film that suppresses flammable vapors, thus preventing potential ignition and enhancing safety during firefighting operations involving flammable liquids. By reapplying the foam within this time frame, firefighters can help ensure that it stays intact and provides continuous protection.

This interval allows for adequate foam coverage while also considering the possibility of the foam breaking down over time or being compromised due to external factors. Regular reapplication during this period is essential for maximizing its effectiveness in suppression efforts.