ISO 3941

Overview

ISO 3941:2025 is the international standard that provides a clear classification system for different types of fires based on the nature of the fuel involved. Published by ISO (International Organization for Standardization), this standard is essential for professionals in fire protection, firefighting, and safety management. It categorizes fires into distinct classes to improve communication and guide the appropriate use of fire extinguishing equipment. The 2025 revision includes updated classifications with the addition of lithium-ion battery fires, reflecting contemporary fire safety challenges.

Key Topics

• Fire Classification by Fuel Type
  ISO 3941 categorizes fires into six classes according to the fuel:

  • Class A: Fires involving solid materials such as wood, cloth, paper, rubber, and many organic plastics that typically burn with glowing embers.
  • Class B: Fires involving liquids or liquefiable solids, requiring consideration of fuel containment and chemical properties (polar or non-polar).
  • Class C: Fires involving gases, where extinguishing requires caution, especially if the gas supply cannot be stopped to avoid explosion risks.
  • Class D: Fires involving metals, which are highly specific in nature; each metal fire needs separate assessment for firefighting.
  • Class F: Fires involving cooking media including vegetable or animal oils and fats, with risks such as oil splashing or explosive reactions if water is used incorrectly.
  • Class L: Newly added class for fires involving lithium-ion cells and batteries, which have unique hazards like rapid energy release, toxic and explosive gases, and potential for electric shock and reignition.

• Hazards and Special Considerations
  The standard provides important safety information related to each fire class, emphasizing the toxicity of combustion products, explosion risks, and the need for tailored firefighting approaches depending on the fire’s fuel source.

• Practical Use in Fire Protection Equipment
  ISO 3941’s classification is widely used to design, test, and select fire extinguishing equipment to ensure compatibility with the fire class, enhancing safety and effectiveness during firefighting operations.

Applications

• Firefighter Training and Operations
  Enables firefighters to quickly identify fire types and apply suitable extinguishing methods, improving response times and safety.

• Fire Extinguisher Labeling and Selection
  Guides manufacturers and safety managers in labeling fire extinguishers and recommending appropriate extinguisher types for different environments.

• Industrial and Residential Fire Safety Planning
  Facilitates risk assessment and fire prevention in workplaces, kitchens, laboratories, and facilities handling flammable materials or lithium-ion batteries.

• Safety Standards Compliance
  Supports compliance with fire safety regulations by providing internationally recognized classifications essential for certifications and audits.

• Battery Storage and Transport Safety
  With the addition of lithium-ion battery fire classification, ISO 3941 helps in managing fire risks related to modern energy storage technologies.

Related Standards

• ISO/IEC Directives Part 1 and 2
  Provide the procedural and editorial framework for developing ISO standards such as ISO 3941.

• ISO 11601
  Related to portable fire extinguishers, complementing ISO 3941 by specifying testing and performance requirements.

• IEC Electropedia and ISO Online Browsing Platform
  Offer terminology databases referenced for consistent use of fire safety terms.

• National Fire Protection Association (NFPA) Standards
  While specific to the US, NFPA 10 and related standards align with ISO classifications for fire extinguisher use and classification.

• Battery Safety Standards (e.g., IEC 62660 and UL 9540-1)
  Provide detailed safety requirements for lithium-ion batteries, supporting the fire classification updates for Class L fires.

Keywords: ISO 3941, fire classification, fire safety standard, fire classes, fire extinguisher classification, lithium-ion battery fires, firefighting, fire protection equipment, Class A fire, Class B fire, Class C fire, Class D fire, Class F fire, Class L fire, combustible materials, fire hazards.