General Definition

• International Building Code (IBC) – USA
  • According to the 2018 International Building Code (IBC,) an accessible entrance is defined as an entrance that complies with the ADA Standards for Accessible Design and ANSI A117.1, ensuring that individuals with disabilities, including those using wheelchairs, can independently enter the building.
• Building Standard Law (BSL) – Japan
  • In Japan, the Building Standard Law (BSL) and its enforcement regulations, along with the Barrier-Free Law, set accessibility requirements.

IBC – Accessible Entrance Requirements

Under IBC Section 1105.1, accessibility requirements for public entrances in buildings are as follows:

• At least 60% of all public entrances must be accessible to individuals with disabilities.
• These accessible entrances must comply with ADA Standards and ANSI A117.1, ensuring features such as:
  • No-step entry (ramps, lifts, or level surfaces)
  • Automatic or easy-to-use doors (minimum clear width and maneuvering space)
  • Signage for accessible routes and entry points
• This applies to most buildings, including offices, retail, and multi-use commercial buildings.
• Exceptions exist for some historic buildings, industrial uses, and certain limited-use facilities.

BSL & Barrier-Free Act – Accessible Entrance Requirements

Under Japan’s Barrier-Free Act (バリアフリー法, Barrier-Free Hō), which applies to public buildings and large private facilities, the accessibility requirements are as follows:

• At least one accessible entrance must be provided for office buildings and administrative facilities.
• The entrance must comply with barrier-free design standards, including:
  • Step-free access (ramped or level entry)
  • Wide doorways for wheelchair users
  • Handrails if needed for sloped entry points
  • Clear signage indicating accessible entry
• Priority Facilities: The requirement is strictly enforced in government buildings, hospitals, and transport hubs, but private buildings may have slightly different mandates depending on size and location.
• The Barrier-Free Act focuses on usability, meaning only one entrance is required as long as it provides full accessibility.

Case Study

Accessible Entrance Design for a 5-Story Office Building (Group B Occupancy) in the USA vs. Japan

• Project Overview
  • A company is constructing a 5-story office building (Group B Occupancy) with a total floor area of 4,500 m² (≈48,500 ft²). The building includes office spaces, meeting rooms, and a main lobby. The project aims to comply with International Building Code (IBC – USA) and Building Standard Law (BSL – Japan) accessibility standards for entrance design.

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5-Story Office Building in Honolulu (IBC Compliance)

• Design Considerations:
  • Main entrance consists of double-leaf doors with a minimum 32-inch (81 cm) clear width per leaf.
  • The building has three public entrances, requiring at least two to be fully accessible (60% rule).
  • A ramp with a 1:12 slope is installed due to a slight elevation change from the sidewalk.
  • Automatic push-button doors are provided at the main accessible entrance.
  • The accessible entrance is connected to an elevator lobby that serves all floors.
• Key Challenges:
  • If the building had fewer than 60% accessible entrances, modifications would be required.
  • Retrofitting existing buildings may pose design challenges, especially in older structures.

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5-Story Office Building in Tokyo (BSL Compliance)

• Design Considerations:
  • At least one entrance is designed to be step-free without requiring a ramp.
  • Automatic sliding doors are used at the main entrance to comply with ease-of-use requirements.
  • The minimum entrance width is 80 cm (31.5 inches), slightly smaller than IBC’s 32-inch (81 cm) requirement.
  • Tactile guide blocks (Tenji blocks) are installed at the entrance, leading toward the reception and elevators.
  • The accessible entrance connects to a barrier-free interior circulation system, including elevators and wide corridors.
• Key Challenges:
  • The building is located in a dense urban area with limited space, making step-free design a priority over ramps.
  • Additional compliance with Tokyo’s Barrier-Free Law may require more internal accessibility modifications.

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Key Findings

1. IBC requires at least 60% of public entrances to be accessible, while BSL mandates only one but strongly prefers step-free access.
2. Japan favors automatic sliding doors in modern office buildings, while IBC allows manual doors with accessible hardware.
3. BSL integrates tactile guide blocks (Tenji blocks) into entrance designs, whereas IBC does not require them.
4. IBC permits up to ½-inch threshold height, whereas Japan prioritizes completely step-free transitions.

Implications for Design

• IBC (US Standard) requires more widespread accessibility, ensuring that the majority of public entrances are usable by all individuals.
• BSL (Japan’s Standard) allows more flexibility, focusing on providing at least one fully accessible entrance, which may be acceptable in smaller buildings.
• Multinational Projects: If a project must comply with both IBC and BSL, designers should plan for at least 60% accessibility compliance to meet IBC’s stricter requirements while ensuring at least one fully accessible entrance for Japan’s Barrier-Free Act.