FAR 25.853a & FAR 25.853d
FAR 25.853A:
FAR 25.853a is a vertical Bunsen burner test designed by the FAA (Federal Aviation Administration) for cabin and cargo compartment materials. The test method is intended for use in determining the resistance of materials to flame when tested according to the 60-sec (i) and KYDEX® 12-sec (ii) vertical Bunsen burner tests. thermoplastic sheet products undergo this test to determine suitability for aircraft interior parts including but not limited to food trays and seating applications.
In this test a specimen is held in a vertical position by a device inside a cabinet and a Bunsen burner (31.80mm (1.500”) flame) is placed beneath it for a given period of time (60 or 12 seconds accordingly). After the given period of time has elapsed, the burner is removed and the specimen is observed. Ignition time, flame time, drip flame time, and burn length are all recorded at the end of the test. The following are descriptions of things recorded during the tests:
| Ignition Time | Length of time burner flame is applied to specimen |
| Flame Time | Time is seconds that the specimen continues to flame after burner flame is removed |
| Drip Flame Time | Time is seconds that any flaming material continues to flame after falling from specimen |
| Burn Length | Distance from original specimen’s edge to farthest evidence of damage to specimen |
The following are requirements for passing the FAR 25.853a test.
| Test | Flame Time (sec) | Average Drip Extinguishing Time (sec.) | Average burn length |
|---|---|---|---|
| (i) 60 sec | < 15 | < 3 | 152.40mm (6”) |
| (ii) 12 sec | < 15 | < 5 | 203.20mm (8”) |
Many KYDEX® sheet products meet the requirements set forth by the FAA. KYDEX® T, KYDEX® 100, KYDEX® 1900, KYDEX® 5555, KYDEX® 6185, KYDEX® 6200, KYDEX® 6565, and KYDEX 5555 are some of the KYDEX® products specifically formulated to be used in aircraft and mass transit vehicles and meet the FAA requirements for this test at 0.71mm (0.028”) and above.
FAR 25.853D:
FAR 25.853d is comprised of two separate tests; OSU Rate of Heat Release and Specific Optical Density of Smoke Generated by Solid Materials. These two tests help to determine the acceptability of the materials to be used in the interiors of aircrafts. More specifically, the OSU rate of heat release theoretically attempts to limit the possibility that certain interior materials with large outer surface areas will flashover, become rapidly involved in a fire, or readily contribute to an existing fire in a crash situation. By testing the materials such contributions to existing fires may be avoided.
The smoke density test, also known as the ASTM F-814 (now retired) but closely follows ASTM E-662, determines the smoke generation of a burning material to help improve egress capability after a fire . Results from the smoke density test are expressed in terms of specific optical density (Ds). Optical density (Ds) readings are taken at 1.5 minutes into the test and at 4 minutes.
The rate of heat release (OSU) is a measurement of the rate at which a burning item releases heat, using the principle of oxygen consumption (calorimetry), which is a critical parameter in fire protection engineering. (The test method for using the OSU calorimeter is published under ASTM E-906, and is a small scale component test). The heat release rate can be used in the characterization of the hazard represented by a given fuel package. Heat release rate can provide information on fire size and fire growth rate. This method tests materials and products under a constant, imposed, external heat flux.
The following are requirements for passing the FAR 25.853d test
| Total Heat Release within First 2 Minutes | ≤ 65 kW * minutes per square meter |
| Peak Heat Release Rate: | ≤ 65 kW per square meter |
| 4.0 Minute Smoke Density (Ds): | ≤ 200 |
KYDEX® 5555, KYDEX® 5555HI, KYDEX® 6565, KYDEX® 6565HI, KYDEX® 6503, KYDEX® 6523HI and KYDEX® FST are some of the KYDEX® products specifically formulated to be used in aircraft and mass transit vehicles and meet the FAA requirements for this test at 0.71mm (0.028”) and above.
Because we cannot anticipate or control the many different conditions under which this information and our products may be used, we do not guarantee the applicability of the accuracy of this information or the suitability of our products in any given situation. Users should conduct their own tests to determine the suitability of each product for their particular purposes. Data in the physical property table represents typical values and are to serve only as a guide for engineering design. Results are obtained from specimens under ideal laboratory conditions. Right to change physical properties as a result of technical progress is reserved. THE PRODUCTS DISCUSSED ARE SOLD WITHOUT WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE, EITHER EXPRESSED OR IMPLIED, EXCEPT AS PROVIDED IN OUR STANDARD TERMS AND CONDITIONS OF SALE. Buyer assumes all responsibility for loss or damage arising from the handling and use of our products, whether done in accordance with directions or not. In no event shall the supplier or the manufacturer be liable for incidental or consequential damages. Also, statements concerning the possible use of our products are not intended as recommendations to use our products in the infringement of any patent. Consult local code and regulatory agencies for specific requirements regarding code compliance, transporting, processing, recycling and disposal of our product. Product not intended for use as a heat resistant surface. Texture, product grade and other conditions may cause variations in appearance.
This information supersedes all previously published data.