Vertical Burn

Vertical Bunsen Burner Test (for aviation)

The Vertical Bunsen Burner test is used by the aerospace/aviation industry to determine the resistance of cabin and cargo compartment materials to a flame applied for either 12- or 60-seconds. It is most commonly used to show compliance with 14 CFR 25.853(a).

Test Methods

  • 14 CFR 23, Appendix F, Part I(d)
  • 14 CFR 25, Appendix F, Part I(b)(4)
  • FAA Fire Test Handbook, Chapter 1
  • Boeing BSS 7230-F1/F2
  • Douglas DMS 1510 & 1511
  • RTCA DO-160G, Section 26.6.2
  • MIL-C-85052, Section 4.5.3.3
Vertical

Test Summary

A test sample is aligned vertically and exposed to a small Bunsen burner flame at its lower edge. The flame is applied for 12 or 60 seconds and then pulled away from the sample. If the sample continues to flame, this flame time is recorded along with any flaming drips that may occur. After the test is over, the burn length is measured. The pass/fail criteria are based on the flame time, drip flame time, and burn length averaged across three test samples.

Test Sample Requirements

Test samples must meet the following requirements:

    • The standard sample size is 3-inch x 12-inch unless the actual size used in the aircraft is smaller.
    • A minimum of 3 samples must be tested.
    • The sample thickness must be no thicker than the minimum thickness to be qualified for use in the airplane. (Except for thick foam parts which are tested in 1/2" thickness.)
    • If the material could react differently depending which direction it is cut, it must be tested in two directions. For example, woven materials (e.g. carpet, fabric, etc.) must be tested with 3 samples cut up the roll and 3 samples cut across the roll.
    • Samples may be tested either as a section cut from a fabricated part as installed in the aircraft or constructed to simulate that part.
    • Fabricated units, such as sandwich panels, may not be separated for testing.
    • The shorter edge of the test sample where the flame is applied must not consist of a finished or protected edge, i.e. it must represent a cross section of the material or part as installed in the aircraft.

Regulatory Requirements

This test is typically used to show compliance with the following U.S. Federal Regulations:

    • 14 CFR 23.853(d)(3)
    • 14 CFR 23.855(b)
    • 14 CFR 25.853(a)
    • 14 CFR 25.855(d)
    • 14 CFR 29.853(a)
    • 14 CFR 29.855(a)

Note 1: In the aviation industry, 14 CFR may also be referred to as "FAR" (Federal Aviation Regulations). You may see the requirements listed as FAR 23.853, FAR 25.853, FAR 25.855, etc.

Note 2: The European Union Aviation Safety Agency (EASA) uses similar Certification Specifications (CS) which correspond to those in the CFR. For example, the EASA regulations are listed as CS 23.853, CS 25.853, etc. These regulations may also be referred to as "JAR" (Joint Aviation Requirements) and listed as JAR 23.853, JAR 25.853, etc.

Products Requiring This Test

Items in commuter or transport category aircraft and in transport category rotorcraft require the Vertical Bunsen Burner Test when they are located in a compartment occupied by the crew or passengers. While there are some exceptions, these items typically include:

Vertical Burn, 12-second
  • Floor Coverings
  • Textiles & Leather
  • Seat Cushions
  • Padding
  • Coated Fabrics
  • Trays and Galley Furnishings
  • Electrical Conduit
  • Air Ducting and Joints
  • Joint and Edge Covering
  • Molded and Thermoformed Parts
  • Trim Strips
  • Cargo Panel Flooring
  • Cargo Covers and Transparencies
Vertical Burn, 60-second
  • Interior Ceiling and Wall Panels
  • Partitions
  • Galley Structure
  • Large Cabinet Walls
  • Structural Flooring
  • Large Stowage Compartments

History of the Vertical Bunsen Burner Test

In 1965, following the deadly United Airlines Flight 727 crash in Salt Lake City, the Federal Aviation Administration (FAA) proposed more stringent requirements for cabin materials which were later adopted in 1967. Prior to 1967, materials were only required to undergo a Horizontal Bunsen Burner Test. The new Vertical Burn requirements were based on the 1951 Federal Specification CCC-T-191b, Method 5902 "Flame Resistance of Cloth, Vertical" with some modifications. This modified test method was incorporated into the Code of Federal Regulations (CFR), Title 14, Part 25 in 1967 through Amendment 25-15.

The Vertical Burn test underwent a few changes since its creation in 1967. Individual manufacturers and organizations also established their own internal versions of the Vertical Burn Test, such as Airbus (ABD0031/AITM 2.0002), Boeing (BSS 7230), McDonnell Douglas (DMS 1510 and 1511), and ASTM International (ASTM F501, withdrawn in 1998).

In order to facilitate improvements to the test standard without constantly changing the CFR, the FAA published Report DOT/FAA/CT-99/15 "Aircraft Materials Fire Test Handbook" in 1990. The tests in this handbook are considered an acceptable equivalent to those in the CFR. The handbook was updated in 2000 to DOT/FAA/AR-00/12, with the 60-second and 12-second Vertical Bunsen Burner Tests located in Chapter 1 of the handbook.

Sources: Federal Register Vol. 32, No. 182

Additional Resources

Resource Description
14 CFR 23.853 Passenger and Crew Compartment Interiors
(Normal, Utility, Acrobatic, and Commuter Category Airplanes)
U.S. Regulations for FAR 23.853 at Amendment 23-62. (Historical)
14 CFR 23.855 Cargo and Baggage Compartment Fire Protection
(Normal, Utility, Acrobatic, and Commuter Category Airplanes)
U.S. Regulations for FAR 23.855 at Amendment 23-49. (Historical)
14 CFR 23, Appendix F Appendix F to Part 23
(Commuter Category Airplanes)
U.S. Regulations, Criteria and Test Procedures, Part 23. (Historical)
14 CFR 25.853 Compartment Interiors
(Transport Category Airplanes)
U.S. Regulations for FAR 25.853 at Amendment 25-116.
14 CFR 25.855 Cargo or Baggage Compartments
(Transport Category Airplanes)
U.S. Regulations for FAR 25.855 at Amendment 25-142.
14 CFR 25, Appendix F Appendix F to Part 25
(Transport Category Airplanes)
U.S. Regulations, Criteria and Test Procedures, Part 25.
14 CFR 29.853 Compartment Interiors
(Transport Category Rotorcraft)
U.S. Regulations for FAR 29.853 at Amendment 29-30.
14 CFR 29.855 Cargo and Baggage Compartments
(Transport Category Rotorcraft)
U.S. Regulations for FAR 29.855 at Amendment 29-30.
FAA Fire Test Handbook,
Chapter 1 		FAA Aircraft Materials Fire Test Handbook (DOT/FAA/AR-00/12); Chapter 1; Vertical Bunsen Burner Test for Cabin and Cargo Compartment Materials.
This handbook provides an acceptable means of compliance with the relevant regulations. This is the preferred test method to find compliance with the listed regulations.
FAA Policy Memo
PS-ANM-25.853-01-R2
 		Flammability Testing of Interior Materials
This policy memo provides guidance on acceptable methods of compliance with the flammability requirements of 14 CFR Part 25 for commonly constructed parts, construction details, and materials.

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