In fabric flammability testing, various evaluations are used to assess the flammability characteristics of fabrics. The specific evaluation methods can vary depending on the standards and regulations being followed. Some commonly used evaluations in fabric flammability testing include:
1. Flame Spread: This evaluation measures the rate at which a flame spreads across the surface of a fabric. It typically involves igniting a fabric sample and observing the flame propagation along the specimen.
2. Afterflame Time: Afterflame time refers to the duration for which a fabric continues to burn or smolder after the ignition source is removed. It measures the fabric's ability to self-extinguish.
3. Afterglow Time: Afterglow time measures the duration for which a fabric emits glowing or smoldering particles after the flame source is removed. It evaluates the fabric's tendency to sustain combustion.
4. Char Length: Char length is the distance between the point of ignition and the farthest extent of the resulting charred area on a fabric sample. It provides an indication of the fabric's propensity for charring and burning.
5. Heat Release Rate: The heat release rate evaluation measures the amount of heat released by a fabric during combustion. It quantifies the fabric's flammability and potential to contribute to fire growth.
6. Ignition Time: Ignition time refers to the time it takes for a fabric to ignite when exposed to a flame or heat source. It is an indicator of the fabric's susceptibility to ignition.
These evaluations, along with other parameters, are often specified in flammability testing standards such as ASTM D6413, NFPA 701, and ISO 15025. The specific evaluation methods and criteria for pass/fail determination can vary depending on the intended application, regulatory requirements, and industry standards.
It's important to consult the relevant flammability testing standard or regulation for precise details on the evaluations and criteria used for fabric flammability testing.