What type of doors are included in the fenestration definition?

The definition of fenestration encompasses any openings in a building's envelope that includes windows, doors, skylights, and other similar features. This term is generally used in relation to how these elements contribute to the building's performance regarding light, airflow, and sometimes thermal insulation.

By including both glass and opaque doors in the definition, it acknowledges that fenestration systems can vary widely in their materials and functions. Glass doors are explicitly included due to their capability to permit natural light and visibility, while opaque doors can serve as functional entry points without contributing visibility or light penetration. As such, both types of doors play critical roles in the overall design and efficiency of a structure.

A narrow interpretation focusing exclusively on one type of door would not capture the complete range of fenestration elements, which is why the correct understanding includes both glass and opaque doors.