- Under the IBC, Assembly Group “A” occupancy includes, among others, the use of a building or structure, or a portion thereof, for the gathering of persons for purposes such as civic, social or religious functions; recreation, food or drink consumption or awaiting transportation.
- “A” Occupancy is subcategorized into:
- A-1, A-2, A-3, A-4 & A-5.
- “A” Occupancy is subcategorized into:
- In Japan’s Building Standards Law (BSL), there is no single “Assembly” (A) category, but these buildings fall under various 集会施設 (Shūkai Shisetsu) – Assembly Facilities and 商業施設 (Shōgyō Shisetsu) – Commercial Facilities, and regulated by:
- 建築基準法 (Kenchiku Kijun-hō) – Building Standards Law (BSL) (for occupancy classification, fire safety, and structural standards)
- 消防法 (Shōbō-hō) – Fire Service Act (for fire protection, emergency exits, and occupant load control)
- 都市計画法 (Toshi Keikaku-hō) – Urban Planning Law (for zoning and land use restrictions)
- 建築基準法 (Kenchiku Kijun-hō) – Building Standards Law (BSL) (for occupancy classification, fire safety, and structural standards)
Assembly Group A-1 Occupancy
Includes assembly uses, usually with fixed seating, intended for the production and viewing of the performing arts or motion pictures including, but not limited to:
- Motion picture theaters
- Symphony and concert halls
- Television and radio studios admitting an audience
- Theaters
Japanese BSL equivalents
- 映画館 (Eigakan) → Motion Picture Theaters
- 劇場 (Gekijō) → Live Performance Theaters
- 音楽ホール (Ongaku hōru) → Concert Halls
- 観覧席を有するスタジオ (Studios with Audience Seating)
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Assembly Group A-2 Occupancy
Includes assembly uses intended for food and/or drink consumption, including, but not limited to:
- Banquet halls
- Nightclubs
- Restaurants
- Taverns and bars
Japanese BSL Equivalent
- 飲食店 (Inshokuten) – Restaurants, bars, taverns
- ナイトクラブ (Naitokurabu) – Nightclubs
- 宴会場 (Enkaijō) – Banquet halls
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Assembly Group A-3 Occupancy
Includes assembly uses intended for worship, recreation, or amusement, and other assembly uses not classified elsewhere in Group A, including, but not limited to:
- Amusement arcades
- Art galleries
- Bowling alleys
- Community halls
- Courtrooms
- Dance halls (not including food or drink consumption)
- Exhibition halls
- Funeral parlors
- Gymnasiums (without spectator seating)
- Lecture halls
- Libraries
- Museums
- Places of religious worship
- Pool and billiard parlors
- Waiting areas in transportation terminals
Japanese BSL Equivalent
- 遊技場 (Yūgijō) – Amusement arcades
- 展示場 (Tenjijō) – Exhibition halls
- 美術館 (Bijutsukan) – Art galleries
- 博物館 (Hakubutsukan) – Museums
- 宗教施設 (Shūkyō shisetsu) – Religious buildings (temples, shrines, churches)
- 体育館 (Taiikukan) – Gymnasiums (without spectator seating)
- 公会堂 (Kōkaidō) – Community halls, civic centers
- 法廷 (Hōtei) – Courtrooms
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Assembly Group A-4 Occupancy
Includes assembly uses intended for viewing of indoor sporting events and activities with spectator seating, including, but not limited to:
- Arenas
- Skating rinks
- Swimming pools
- Tennis courts
Japanese BSL Equivalent
- アリーナ (Arīna) – Indoor arenas
- 室内スケートリンク (Shitsunai sukēto rinku) – Indoor skating rinks
- 屋内プール (Okunai pūru) – Indoor swimming pools
- 体育館 (Taiikukan) with seating – Gymnasiums with spectator seating
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Assembly Group A-5 Occupancy
Includes assembly uses intended for participation in or viewing outdoor activities, including, but not limited to:
- Amusement park structures
- Bleachers
- Grandstands
- Stadiums
Japanese BSL Equivalent
- 競技場 (Kyōgijō) – Sports stadiums
- スタジアム (Sutajiamu) – Large stadiums
- 野外劇場 (Yagai gekijō) – Outdoor amphitheaters
- 遊園地施設 (Yūenchi shisetsu) – Amusement park structures
- 観覧席 (Kanranseki) – Grandstands, bleachers
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Key Differences
- IBC categorizes assembly buildings into A-1 to A-5 based on function, while BSL divides them into entertainment, public, dining, and sports facilities.
- BSL enforces stricter fireproofing (耐火建築物) for large public buildings, stadiums, and entertainment venues due to earthquake risks.
- IBC provides more explicit occupant load calculations, while BSL applies stricter zoning regulations for large-scale assembly buildings.
- Both codes prioritize egress, fire protection, and emergency evacuation planning, but BSL incorporates additional seismic design requirements for densely populated venues.