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Japan Building Standard Law — Fire Resistance and Zones

Updated Mar 26, 2026
Japanese fire safety: quasi-fireproof, fireproof construction, fire prevention districts, evacuation.

Building Standard Law (BSL) + Building Standard Law Enforcement Order: Fire prevention districts designated in dense urban areas. Within fire prevention districts: buildings >3 stories or >100m2 must be fireproof construction. Quasi-fire prevention districts: buildings >4 stories must be fireproof, or >3 stories must be quasi-fireproof. Fireproof construction: main structural parts (columns, beams, walls, floors, stairs, roof) rated 1-3 hours depending on height. Quasi-fireproof: 45 min rating. Fire compartmentation: different rules by building use and size. Interior finish restrictions: quasi-incombustible, fire-retardant, or incombustible for corridors and stairs. Smoke control: natural or mechanical for buildings >31m. Evacuation: 2 exit routes required for floors >200m2 in certain uses.

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