Which is a sign that indicates a space may be a confined space?

A space is considered a confined space when it has limited access or egress, which means that entry and exit are restricted. This often leads to potential hazards that may not be present in more open environments. For instance, the limited access can make it difficult for workers to leave the area quickly in an emergency and can also hinder necessary ventilation, leading to the accumulation of potentially harmful atmospheres.

In contrast, a high ceiling typically allows for easier movement and does not inherently imply restrictions to access or safety. Natural illumination is indicative of adequate light conditions, which is generally a positive sign in terms of safety, as it enhances visibility. Free-flowing air is also a good indication of a safe working environment, as it suggests adequate ventilation, reducing the risks associated with confined spaces, such as hazardous gases or insufficient oxygen. Thus, access limitations are the defining characteristic that indicates a space may present confined space hazards.