What should be done first when performing horizontal ventilation?

The primary objective of horizontal ventilation is to remove smoke, heat, and gases from a structure while improving visibility and conditions for firefighting and escape. The correct approach in this scenario is to open the leeward side first.

By opening the leeward side initially, you are allowing the smoke and heat to be displaced effectively by the wind, as the wind will carry these elements away from the structure. This forward-thinking tactic can create a pressure differential that helps vent the interior of the building more efficiently. It also helps to prevent smoke from being pushed deeper into the structure, particularly if there are firefighters already engaged inside.

Opening the leeward side first creates a more controlled environment for subsequent actions, whether that involves deploying a handline or performing other firefighting operations. This prioritization supports the overall goal of enhancing safety for both occupants and firefighters, facilitating a more effective response to the incident. In summary, the sequence of opening the leeward side enhances the effectiveness of the ventilation operation and ultimately contributes to better overall incident management.