In which condition should mechanical ventilation not be needed?

Mechanical ventilation is not needed when natural ventilation is sufficient because natural ventilation can effectively provide the necessary airflow and air quality for a space without the need for additional mechanical systems. Natural ventilation relies on the movement of outdoor air through openings, such as windows, vents, and doors, to maintain comfort and indoor air quality.

In climates where temperatures and weather conditions allow for fresh air to flow freely, this method can often meet or exceed ventilation requirements. This scenario reduces energy consumption as it eliminates the need for powered equipment, benefiting both environmental and economic aspects.

While the other situations might suggest scenarios where mechanical ventilation could be beneficial, they do not inherently provide conditions where mechanical ventilation would be unnecessary. For instance, residential applications typically require some form of ventilation, secured environments often need controlled air quality for safety, and areas with hazardous materials would certainly require more stringent ventilation measures to mitigate potential risks.