In a horizontal ventilation situation, which windows should be opened first?

In a horizontal ventilation scenario, opening windows on the downwind side of the building is the best approach. This method helps to effectively remove smoke and heat from the structure. By starting on the downwind side, the natural flow of air can assist in carrying out the smoke while ensuring that fresh air is drawn in from the open windows or doors on the upwind side, creating a more efficient and effective ventilation process.

When considering the dynamics of smoke and heat movement, opening the downwind side helps to establish a clear path for the smoke to escape. This is crucial in reducing the potential for backdrafts or other dangerous conditions that can occur if proper ventilation is not established.

In contrast, opening windows on the upwind side first would limit the outflow of smoke and could lead to smoke being pushed back into the building. The crosswind side might also introduce variables that can disrupt the intended flow of air. Focusing solely on the largest window might seem intuitive but doesn't take into account the air dynamics at play, which are crucial in fire situations.

Therefore, prioritizing the opening of windows on the downwind side aligns with safe firefighting practices and enhances the effectiveness of horizontal ventilation.