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Aircraft

Beside specifications agreed for operational reasons between manufacturers and purchasers of aircraft, aeroplanes and the materials used in their constructions must comply with national and international regulations.

Two international standards are used at this moment all around the world:

The Federal Airways Regulation part 25 (FAR part 25, especially the appendix F which describes all the test methods for materials and components of the pressurised section of fuselage). The European equivalent is the JAR part 25 paper.

The requirements of these two references are largely similar, and the plane makers have integrated these requirements in their internal standard which are:

  • ABD 0031 describing AITM test methods for Airbus
  • Boeing Safety Standard (BSS) for Boeing.
      • FAR 25.853 (a) Bunsen burner tests for cabin and cargo compartment materials
      • FAR 25.853 (c) Amendment 25-83 Oil burner test for seat cushions
    • FAR 25.853 (d) Smoke generation of aerospace materials (flaming mode)
      • Boeing BSS 7239 Analysis of CO, HF, HCN, HCI, HBr, SO2, and NOx in combustion gases



JAR/FAR Part 25, Appendix F - Part I

Flammability, 60s vertical Bunsen burnerSee Figure 1
PartsRequirement
Interior ceiling panels - Interior wall panels
Partitions - Galley structures and panels
Large cabinet walls - Structural flooring
Dado panels - Passenger service units
Door linings incl. slide container - Class dividers
Door frame linings - Light panels
Linings for stowage compartments
Floor beam struts - Floor structure
Pressure bulkheads - Fuselage skin
Fuselage frames - Door structure
  • After burn length (average) shall not exceed 152 mm.
  • After flame time (average) shall not exceed 15 s.
  • After flame time of drips (average) shall not exceed 3 s.

Fig 1


Flammability, 12s vertical Bunsen burner
Floor Covering - Textiles (incl. draperies and upholstery)
Seat cushions - Decorative and non-decorative coated fabrics
Padding - Leather
Furnishings of trays and galleys - Electrical conduit
Thermal and acoustical insulation - Insulation covering
Air ducting - Joint and edge covering
Insulation blankets - Cargo covers
Transparencies - Moulded and thermoformed parts
Air ducting joints
Linings (incl. floor panels) of all cargo and baggage compartments
  • After burn length (average) shall not exceed 203 mm.
  • After flame time (average) shall not exceed 15 s.
  • After flame time of drips (average) shall not exceed 5 s.

Flammability, horizontal Bunsen burnerSee Figure 2
Acrylic windows and signs - Seat belts
Structural window panes elastomeric materials
Edge lighted instrument assemblies consisting of two or more instruments in a common housing
Cargo and baggage equipment, including containers, bins pallets, etc.
  • Burn rate (average) shall not exceed 64 mm/min.
All other material not included in the first items
  • Burn rate (average) shall not exceed 102 mm/min.
Fig 2


Flammability, 45° Bunsen burner
Liners of class B or E cargo and baggage compartments
  • The flame shall not penetrate (pass through) the material during application of the flame or subsequent to its removal.
  • After flame time (average) shall not exceed 15 s..
  • After glow time (average) shall not exceed 10 s.

Flammability, 60° Bunsen burnerSee Figure 3
Insulation on electrical wire and electrical cable installed in any area of the fuselage
  • After burn length (average) shall not exceed 76 mm.
  • After flame time (average) shall not exceed 30 s.
  • After flame time of drips (average) shall not exceed 3 s.




JAR/FAR Part 25, Appendix F - Part II

Flammability of Seat Cushions
Seat cushions, except those on flight crew member seats
  • For at least two-thirds of the total number of the specimens sets tested, the burn length shall not reach the side of the cushion opposite the burner.
  • The burn length shall not exceed 432 mm (17 inches).
  • The average percentage weight loss shall not exceed 10%.
  • For at least two-thirds of the total number of the specimens sets tested the weight loss shall not exceed 10%.

JAR/FAR Part 25, Appendix F - Part III

Flame Penetration of Cargo LinersSee Figure 4
Ceiling and sidewall liner panels of Class C and Class D cargo or baggage compartment
  • No flame penetration of any specimens within 5 minutes after application of the flame source.
  • Maximum (peak) temperature measured 102 mm (4 inches) above the upper surface of the horizontal test sample shall not exceed 204°C.

Fig 4






JAR/FAR Part 25, Appendix F - Part IV

Heat Release and Heat Release RateSee Figure 5
Ceiling panels, Wall panels, Partitions, Galley, outer surfaces of, Large cabinet walls, Dado panels, Door linings incl. slide container, Passenger service units, Class dividers, Door frame linings, Storage compartments
  • The (average) total positive heat release (HR) over the first two minutes shall not exceed 65 kW min/m2.
  • The (average) maximum heat release rate (HRR) during the five minutes test shall not exceed 65 kW/m2.

Fig 5





JAR/FAR Part 25, Appendix F - Part V

Smoke Density / Interior and Equipment parts
Ceiling panels, Wall panels, Partitions, Galley, Large cabinet walls, Dado panels, Door linings incl. slide container, Passenger service units, Class dividers, Door frame linings, Storage compartments
  • The maximum specific optical smoke density (average) shall not exceed.
  • The Dm = 150 within 4 minutes test duration under flaming conditions.
Floor beam struts, Floor structure, Pressure bulkheads
  • See Table 32

The JAR/FAR part 25 regulation does not mention the smoke toxicity assessment. The plane makers has developed internal standards to assess the smoke toxicity. The test method is based on the smoke chamber analysis and analyse during the same round the opacity and the toxicity of smokes.

For AIRBUS: AITM 3.0005 test method
For BOEING: BSS 7239 test method

Toxicity / Interior and Equipment parts
Insulation on. Wire/Cable		See Figure 6
Component parts or sub-assemblies, electrical cable/wire insulation materials, and non metallic
Structural parts, that are intended for use inside the pressurized section of the fuselage		The average concentration (in parts per million, ppm) of following gas components of smoke shall not exceed the limits, listed table below, within the relevant test duration under the required test conditions.

Limiting values as specified in the ABD 00031 Airbus Industrie material test specification:
  • Hydrogen Fluoride HF
100 ppm vol
  • Hydrogen Chloride HCI
150 ppm vol
  • Hydrogen Cyanide HCN
150 ppm vol
  • Sulfur Dioxide SO2 / H2S
100 ppm vol
  • Nitrous Gases NO / NO
100 ppm vol
  • Carbon Monoxide CO
1000 ppm vol
Fig 6




No requirement

Flammability of heat shrinkable tubings
Heat shrinkable tubings used in any area of the fuselage
  • After burn length (average) shall not exceed 76 mm.
  • After flame time (average) shall not exceed 30 s.
  • After flame time of drips (average) shall not exceed 3 s