Feb 24,  · How do NFPA codes classify occupancy type compared to the IBC Occupancy Group classification? As part of its commitment to enhancing public safety, NFPA makes its codes and standards available online to the public for free. Assembly – An occupancy (1) used for a gathering of 50 or more persons for deliberation, worship, entertainment, eating, drinking, amusement, awaiting transportation, or similar uses; .