The Federal Aviation Administration (FAA) has developed FAR 25.853, a testing process used to determine aircraft interior materials’ flame resistance. While the FAA outlines various criteria within the test to ensure safe materials are used in aircraft manufacturing, it doesn’t mention adhesives’ role in these materials.
Let’s review what FAR 25.853 is and discuss what it means for adhesives.
What is FAR 25.853?
FAR 25.853 is a Bunsen burner test for cabin and compartment materials. While the specific criteria can vary depending upon the size of the aircraft and application being tested, overall, it encompasses:
- Interior ceiling panels
- Wall panels
- Galley ways and furnishings
- Seat cushions
- Stowage compartments
FAR 25.853 sets flame requirements that a material cannot exceed in order to be used in an aircraft. For example, materials in interior compartments occupied by crew or passengers:
- Must be self-extinguishing when tested vertically
- Have an average burn length that does not exceed 6 inches
- Have a flame time after removal of the flame that does not exceed 15 seconds
- Have drippings from the test specimen that do not continue to flame for more than an average 3 seconds after falling
What Does This Mean for Adhesives?
Adhesives serve an important role in aircraft interior assembly. Types of adhesives include:
- Attachment and heat seal adhesives
- Contact adhesives and skin to core composites
- Embossing resins and laminate adhesives
Adhesives can improve a finished material’s ability to pass the test, but it depends on the following:
- With substrates that already have good flammability properties, the adhesive selection is less crucial.
- For a visual: two pieces of aluminum bonded together using a non-flame retardant adhesive or a flame retardant adhesive will still be more resistant to the flame than other substrates.
- With substrates that are likely to be more flammable, then the use of a flame retardant adhesive is more critical.
- For a visual: two pieces of paper bonded together have increased flame resistance when adhered with a flame retardant adhesive than they do when adhered with a non-flame retardant adhesive.
Adhesives play an important role in determining an overall material’s flame resistance.
Bostik manufactures both non-flame retardant and flame retardant adhesives that are compliant with FAR 25.853. For more information on our smart adhesive products, call 800-7-BOSTIK. You can also visit www.bostik-aerospace.com, or www.bostik.com/us.