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“H” Occupancy

General Definition

  • High-Hazard Group “H” Occupancy refers to buildings or portions thereof used for manufacturing, processing, storage, or handling of hazardous materials that pose a significant fire, explosion, or health risk, and grouped under H-1, H-2, H-3 & H-4.
    • Both the International Building Code (IBC) and Japan’s Building Standard Law (BSL) classify hazardous occupancy based on the type and quantity of hazardous materials stored or used.
  • In Japan’s Building Standards Law (BSL), such high-risk facilities are classified under 危険物施設 (Kikenbutsu Shisetsu) – Hazardous Material Facilities and regulated under 消防法 (Shōbō-hō) – The Fire Service Act.

IBC High-hazard Group H-1 Occupancy

  • Detonable pyrophoric materials
  • Explosives:
    • Division 1.1,
    • Division 1.2,
    • Division 1.3
    • Division 1.4
    • Division 1.5
    • Division 1.6
  • Organic peroxides, unclassified detonable
  • Oxidizers, Class 4
  • Unstable (reactive) materials, Class 3 detonable and Class 4

BSL Equivalents for IBC Hazardous Group H-1

  • 火薬工場 (Kayaku Kōjō) – Explosives Manufacturing Facilities
  • 火薬貯蔵施設 (Kayaku Chozō Shisetsu) – Explosives Storage Facilities
  • 有機過酸化物貯蔵施設 (Yūki Kasankabutsu Chozō Shisetsu) – Organic Peroxide Storage Facilities
  • 酸化剤製造・貯蔵施設 (Sankazai Seizō / Chozō Shisetsu) – Oxidizer Manufacturing and Storage
  • 不安定反応性物質施設 (Fuantei Hannōsei Busshitsu Shisetsu) – Unstable Reactive Materials Facilities

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IBC High-hazard Group H-2 Occupancy

  • Class I, II or IIIA flammable or combustible liquids that are used or stored in normally open containers or systems, or in closed containers or systems pressurized at more than 15 pounds per square inch gauge (103.4 kPa).
  • Combustible dusts where manufactured, generated or used in such a manner that the concentration and conditions create a fire or explosion hazard based on information prepared in accordance with Section 414.1.3.
  • Cryogenic fluids, flammable.
  • Flammable gases
  • Organic peroxides, Class I.
  • Oxidizers, Class 3, that are used or stored in normally open containers or systems, or in closed containers or systems pressurized at more than 15 pounds per square inch gauge (103 kPa).
  • Pyrophoric liquids, solids and gases, non-detonable.
  • Unstable (reactive) materials, Class 3, non-detonable.
  • Water-reactive materials, Class 3.

BSL Occupancies Corresponding to IBC Group H-2

  • 可燃性液体貯蔵施設 (Kanensei Ekitai Chozō Shisetsu) – Flammable and Combustible Liquid
  • 可燃性粉塵施設 (Kanensei Funjin Shisetsu) – Combustible Dust Facilities
  • 可燃性低温液体施設 (Kanensei Teion Ekitai Shisetsu) – Flammable Cryogenic Fluids Facilities
  • 可燃性ガス施設 (Kanensei Gasu Shisetsu) – Flammable Gas Storage and Processing Facilities
  • 有機過酸化物貯蔵施設 (Yūki Kasankabutsu Chozō Shisetsu) – Organic Peroxide Storage Facilities
  • 酸化剤製造・貯蔵施設 (Sankazai Seizō / Chozō Shisetsu) – Oxidizer Manufacturing and Storage Facilities
  • 自然発火性物質貯蔵施設 (Shizen Hakka-sei Busshitsu Chozō Shisetsu) – Pyrophoric Material Storage Facilities
  • 不安定反応性物質施設 (Fuantei Hannōsei Busshitsu Shisetsu) – Unstable Reactive Materials Facilities
  • 水反応性物質施設 (Mizu Hannōsei Busshitsu Shisetsu) – Water-Reactive Materials Storage Facilities

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IBC High-hazard Group H-3

  • Class I, II or IIIA flammable or combustible liquids that are used or stored in normally closed containers or systems pressurized at 15 pounds per square inch gauge (103.4 kPa) or less.
  • Combustible fibers, other than densely packed baled cotton, where manufactured, generated or used in such a manner that the concentration and conditions create a fire or explosion hazard based on information prepared in accordance with Section 414.1.3.
  • Consumer fireworks, 1.4G (Class C, Common)
  • Cryogenic fluids, oxidizing
  • Flammable solids
  • Organic peroxides, Class II and III Oxidizers, Class 2
  • Oxidizers, Class 3, that are used or stored in normally closed containers or systems pressurized at 15 pounds per square inch gauge (103 kPa) or less
  • Oxidizing gases Unstable (reactive) materials, Class 2 Water-reactive materials, Class 2

BSL Occupancies Corresponding to IBC Group H-3

  • 可燃性液体貯蔵施設 (Kanensei Ekitai Chozō Shisetsu) – Flammable and Combustible Liquid Storage Facilities
  • 可燃性繊維施設 (Kanensei Seni Shisetsu) – Combustible Fibers Storage and Processing Facilities
  • 消費者向け花火貯蔵施設 (Shōhisha-muke Hanabi Chozō Shisetsu) – Consumer Fireworks Storage Facilities
  • 酸化性低温液体施設 (Sankasei Teion Ekitai Shisetsu) – Oxidizing Cryogenic Fluids Facilities
  • 可燃性固体貯蔵施設 (Kanensei Kotai Chozō Shisetsu) – Flammable Solids Storage
  • 有機過酸化物貯蔵施設 (Yūki Kasankabutsu Chozō Shisetsu) – Organic Peroxide Storage (Class II & III)
  • 酸化剤貯蔵施設 (Sankazai Chozō Shisetsu) – Oxidizer Storage Facilities (Class 2 & 3 in Closed Containers)
  • 酸化性ガス貯蔵施設 (Sankasei Gasu Chozō Shisetsu) – Oxidizing Gas Storage Facilities
  • 不安定反応性物質施設 (Fuantei Hannōsei Busshitsu Shisetsu) – Unstable Reactive Materials (Class 2)
  • 水反応性物質施設 (Mizu Hannōsei Busshitsu Shisetsu) – Water-Reactive Materials Storage (Class 2)

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IBC High-hazard Group H-4

  • Corrosives
  • Highly toxic materials
  • Toxic materials

BSL Occupancies Corresponding to IBC Group H-4

  • 腐食性物質貯蔵施設 (Fushokusei Busshitsu Chozō Shisetsu) – Corrosive Materials Storage Facilities
  • 毒性物質貯蔵施設 (Dokusei Busshitsu Chozō Shisetsu) – Toxic Materials Storage Facilities
  • 特殊毒性ガス施設 (Tokushu Dokusei Gasu Shisetsu) – Highly Toxic Gas Storage Facilities
  • 毒劇物製造施設 (Dokugekibutsu Seizō Shisetsu) – Toxic Chemical Manufacturing Facilities
  • 医薬品製造施設 (Iyakuhin Seizō Shisetsu) – Pharmaceutical Manufacturing Plants (Toxic Substances)
  • 環境汚染物質貯蔵施設 (Kankyō Osenshitsu Busshitsu Chozō Shisetsu) – Environmental Contaminant Storage Facilities

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IBC High-hazard Group H-5

Semiconductor fabrication facilities and comparable research and development areas in which hazardous production materials (HPM) are used and the aggregate quantity of materials is in excess of those listed in Tables 307.1(1) and 307.1(2) shall be classified as Group H-5. Such facilities and areas shall be designed and constructed in accordance with IBC Section 415.11.

BSL Occupancies Corresponding to IBC Group H-5

  • 半導体製造施設 (Handōtai Seizō Shisetsu) – Semiconductor Fabrication Facilities
  • 研究開発施設 (Kenkyū Kaihatsu Shisetsu) – Research and Development Facilities (Using HPMs)
  • 超純水処理施設 (Chōjun-sui Shori Shisetsu) – Ultrapure Water Processing Facilities
  • 特殊ガス貯蔵施設 (Tokushu Gasu Chozō Shisetsu) – Specialty Gas Storage Facilities
  • 化学エッチング施設 (Kagaku Etchingu Shisetsu) – Chemical Etching and Lithography Processing Plants
  • クリーンルーム施設 (Cleanroom Shisetsu) – Cleanroom Facilities (Handling Hazardous Production Materials)

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Key Differences:

  • BSL does not use an H-1 to H-5 classification but categorizes hazardous buildings by material type (explosives, flammable substances, toxic chemicals, semiconductors, etc.).
  • BSL enforces stricter location restrictions for hazardous buildings, often requiring specialized industrial zones far from residential areas.
  • Cleanroom and laboratory facilities in Japan have additional compliance requirements under BSL, ensuring fire-resistant construction, emergency ventilation, and hazardous material containment.
  • Semiconductor fabrication falls under multiple Japanese laws based on material use