Which type of ventilation is required for enclosed spaces containing gasoline, machinery or fuel tanks?

• A. Natural supply and mechanical
• B. Forced ventilation
• C. Natural only
• D. Mechanical only

Answer: (D)

Ventilating enclosed spaces that contain gasoline, machinery, or fuel tanks must be done with powered, mechanical ventilation. Gasoline vapors are flammable and can accumulate in pockets, especially in lower parts of a space; relying on natural air movement is unpredictable and often insufficient to keep vapor concentrations below safe levels. A mechanical ventilation system provides a controlled, continuous air exchange that actively removes vapors and brings in fresh air, reducing ignition and health risks. Forced ventilation is a type of mechanical ventilation, but the essential requirement is that the space be ventilated by a powered system rather than relying on natural flow alone, which is why mechanical only is the appropriate choice.