How should airflow be controlled before starting a fire in a closed setting?

Opening windows for cross ventilation is the best practice for controlling airflow before starting a fire in a closed setting. Cross ventilation allows fresh air to enter the area, thereby reducing the buildup of hazardous gases and ensuring that there is sufficient oxygen available for combustion. This technique promotes a safer environment by facilitating the flow of air through the space, which can help in the proper functioning of burning materials and prevent the accumulation of potentially harmful smoke and gases.

In contrast, sealing all doors and windows would restrict airflow, leading to dangerous conditions such as insufficient oxygen for combustion and a higher risk of smoke inhalation. Using electric fans for circulation might not effectively establish cross ventilation and could also pose safety concerns if flammable materials are present. Turning off HVAC systems could disrupt overall air circulation and may also hinder the introduction of fresh air or the removal of smoke, making it less safe compared to having open windows to allow air movement.