What should you observe during an indirect attack to ensure effectiveness?

During an indirect attack, the goal is to cool down the fire and reduce its intensity before moving in for a more direct approach. Observing that the room begins to darken is an important indicator of the effectiveness of this technique. This darkening suggests that the smoke and heat are being driven down and cooled, indicating that water vapor is condensing, which can help to reduce the overall temperature of the superheated gases.

In contrast, if the fire intensity were to increase, it would suggest that the indirect attack may not be functioning as intended, potentially indicating that the heat and smoke are still being pushed into the upper areas without sufficient cooling or suppression. Quick dissipation of smoke could indicate that air is being introduced into the fire environment, which might be counterproductive during an indirect attack. Lastly, temperature easing is also a sign that the attack is effective, but the most visual and immediate cue during this technique is usually the darkening of the space, as it directly relates to changing conditions within the fire environment.