What is one of the key tenets that is NOT required for the indirect method of fire attack using fog nozzles?

The indirect method of fire attack using fog nozzles does not specifically require that ventilation occurs prior to starting water flow. This technique often involves applying water to create steam in a confined space to absorb heat and lower the temperature, even in areas without prior ventilation. The primary focus in the indirect approach is on using water effectively to control the fire's heat and spread, regardless of the ventilation status at the moment water is applied.

In practice, initiating water flow quickly helps to control the fire before it can spread further. Additionally, it’s crucial for heat absorption to occur through steam as the water turns to steam, which helps cool the environment. Applying water in high volume plays a significant role in maximizing the steam production and enhancing the effectiveness of this method. However, ventilation is not a prerequisite for starting the indirect attack, making this particular tenet not required in the method's execution.