Which is a key characteristic of an exhausted enclosure?

An exhausted enclosure is specifically designed to effectively remove contaminated air and hazardous fumes, which highlights the importance of airflow in maintaining safety in environments dealing with flammable gases or hazardous materials. The fan plays a critical role in this system by actively drawing air out of the enclosure, thus reducing the concentration of airborne contaminants and preventing them from accumulating to dangerous levels. This proactive approach to ventilation is essential for ensuring that the air quality remains safe for laboratory personnel.

Other options do not represent key characteristics of an exhausted enclosure. While general ventilation might apply to a broader context, it does not specifically address the focused aim of an exhausted enclosure, which is to contain and remove hazardous substances directly. Similarly, while some exhausted enclosures might be involved in the storage of hazardous materials, this is not an inherent characteristic as their primary function relates to airflow and containment rather than storage. Finally, the presence of mechanical components, like fans, contrasts with the notion of having no mechanical components, underscoring the distinction of an exhausted enclosure as an active system rather than a passive one.