ASTM D635, ISO 3795 Flammability

ASTM D635, ISO 3795 Flammability Scope:

Flammability ASTM D635 standards assess the ignition or combustion properties of certain materials such as plastics. ASTM D635 flammability test determines the rate of burning of substantial thick-walled plastics. This test is mainly used for quality checks, production benchmarks, and material comparisons. It is not used as a criterion for fire-related risks. This test assesses the ignition or combustion properties of certain materials such as those used in the production of plastic items.

Test Procedure:

In the ASTM D635 procedure for the Flammability test, a sample is oriented either vertically or horizontally and placed in the test chamber. Then, the flame is applied using a Bunsen Burner for a measured time. Finally, as the flame propagates, the time or distance at which the flame is put off is measured.

Density, pigments, any anisotropy of the material, and specimen thickness are only a few examples of the variables that will have an impact on the pace of burning and other burning phenomena. Whether comparing the same or different materials, test data must only be compared for specimens of comparable thickness. With increasing thickness, the rate of burning and other burning phenomena will change.

The specimens are put through a precise set of laboratory test procedures in this ASTM D635 process. This test  won’t always be able to forecast changes in the fire-test response characteristics measured if new test conditions are substituted or the end-use settings are altered. As a result, only the fire-test-exposure conditions specified in this process are valid for the results.

Video 01: Burning plastic sheets

Specimen size:

ASTM D635 sample sizes are 125 mm × 13 mm × required thickness ‘t’ to be rated

ISO 3795 sample sizes are 100 mm × 356 mm (4 inches × 14 inches) x 13mm (0.5 inch)

Data:

Time duration before the fire extinguishes

The distance through the burn propagation

The linear burning rate (mm per minute)

Mass of cotton ignited in case fire drops

Conclusion:

ASTM D635 is a standard test method for rate of burning or extent and time of burning of plastics in a horizontal position. This test is mainly used for quality checks, production benchmarks, and material comparisons. It is not used as a criterion for fire-related risks.