Which major occupancy group is primarily related to assembly according to Part 3?

The major occupancy group primarily related to assembly according to Part 3 of the building code is Group A. This classification encompasses a wide range of facilities where people gather for various purposes, including entertainment, worship, recreation, and civic functions. The intent behind this classification is to ensure that structures designed for assembly accommodate specific safety and accessibility requirements due to the potential for large crowds, which can present unique challenges in terms of egress, fire safety, and occupancy limits.

For example, places like theaters, auditoriums, sports arenas, and convention centers all fall under Group A. These buildings require careful consideration of factors such as means of egress, fire protection measures, and occupancy load calculations to safeguard the public during events.

In contrast, the other occupancy groups—B, C, and D—pertain to different categories such as business and personal service (Group B), residential (Group C), and mercantile (Group D), each with their own specific codes and regulations that do not focus primarily on assembly. Therefore, Group A is the correct classification that aligns specifically with buildings designed for assembly purposes in the context of the building code.