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    Fire Extinguishers are Required in Aircraft Hangars

    By Mark Conroy



    The construction and fire protection requirements for aircraft hangars are contained in NFPA 409, Standard on Aircraft Hangars. Aircraft hangars are categorized into four groups. Group I has the largest fire area allowance and Group III has the smallest. A Group IV hangar is a structure with a rigid steel frame and covered by a membrane fabric with no limit to fire area. Regardless of the size or construction materials, all hangars are required to have portable fire extinguishers installed.

    For Group I, II, III, and IV aircraft hangars, wheeled and handheld extinguishers are required to be provided in accordance with NFPA 10. In aircraft storage and servicing areas, the distribution of extinguishers is required to be in accordance with the extra hazard classification for Class B Hazards. A single fire area within Group I, II, and III aircraft storage and servicing areas is based on the types of construction outlined in the following table.

    Service Collar Information

    As a minimum, the verification of service collar is required to provide the following information:
    • Month and year the extinguisher valve was removed
    • Name of the agency performing the work
      Group III Group II Group I
    Construction Type Maximum Single Fire Area (ft2) Maximum Single Fire Area (ft2) Maximum Single Fire Area (ft2)
    Type I (442) 30,000 40,000 Over 40,000
    Type I (332) 30,000 40,000 Over 40,000
    Type II (222) 20,000 40,000 Over 40,000
    Type II (111) 15,000 40,000 Over 40,000
    Type III (211) 15,000 40,000 Not Allowed
    Type IV (2HH) 15,000 40,000 Not Allowed
    Type II (000) 12,000 40,000 Not Allowed
    Type III (200) 12,000 40,000 Not Allowed
    Type V (111) 8,000 40,000 Not Allowed
    Type V (000) 5,000 40,000 Not Allowed

    The importance of knowing whether a hangar is Group I, II, III, and IV relates to the size and type of fire protection system required to be installed, although it helps to know types when dealing with owners and other fire protection contractors. Where portable extinguishers are installed in locked cabinets (to preclude the possibility of theft) in Group III aircraft hangars, NFPA 409 requires that each tenant and aircraft owner be provided with a key for the locks on the extinguisher cabinets.

    The distribution of extinguishers in other areas of aircraft hangars is required to be in accordance with light, ordinary, or extra hazard occupancy, based on an analysis of each room or area. All buildings need a complement of extinguishers rated Class A for common combustible fires. So areas such as offices and parts storage will have Class A rated extinguishers throughout. There’s also a need for Class B rated extinguishers in parts areas where flammable liquids are stored, so multi-purpose dry chemical extinguishers are installed unless the owner desires a clean agent, then larger halogenated agent extinguishers are a prime choice.

    The dollar-per-square-foot value of an aircraft hangar plus its contents is very high. Therefore hangar owners and aircraft owners are very interested in proper fire protection throughout these buildings. Your knowledge of the code requirements and which extinguishers match each area enables these stakeholders to have the best and most appropriate wheeled and hand-portable fire extinguishers readily available to protect their assets.


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