In the context of commercial construction projects in Australia, a "door" refers to a movable barrier used to cover an opening in a wall or partition, which allows access, egress, and security between different spaces within a building or between the interior and exterior.

Doors in commercial construction are designed to meet specific functional, aesthetic, and regulatory requirements. Here are some key aspects:

1. Types of Doors:
   - Swing Doors: Traditional hinged doors that open inward or outward.
   - Sliding Doors: Doors that slide horizontally along a track.
   - Revolving Doors: Doors that rotate around a central axis, often used in high-traffic areas.
   - Automatic Doors: Doors that open automatically via sensors or push buttons, commonly used in retail and healthcare facilities.
   - Fire Doors: Specially constructed doors that provide fire resistance to prevent the spread of fire and smoke.

2. Materials:
   - Wood: Often used for interior doors due to its aesthetic appeal.
   - Metal: Commonly used for exterior doors or doors requiring high security.
   - Glass: Used for aesthetic purposes and to allow light transmission, often in office spaces.
   - Composite Materials: Combining different materials to achieve specific performance characteristics.

3. Regulatory Compliance:
   - Building Code of Australia (BCA): Doors must comply with the BCA, which sets out requirements for fire resistance, accessibility, and energy efficiency.
   - Australian Standards (AS): Specific standards such as AS 1905.1 for fire-resistant doorsets and AS 1428.1 for design for access and mobility.

4. Accessibility:
   - Doors must be designed to be accessible to people with disabilities, including appropriate width, handle height, and ease of operation, in compliance with the Disability Discrimination Act (DDA) and relevant Australian Standards.

5. Security:
   - Doors in commercial buildings often incorporate security features such as locks, access control systems, and reinforced materials to prevent unauthorized access.

6. Acoustic Performance:
   - In environments where noise control is important, such as offices or conference rooms, doors may be designed with acoustic insulation properties.

7. Energy Efficiency:
   - Doors should contribute to the overall energy efficiency of the building, with considerations for thermal insulation and airtightness.