Permeation is defined as:

• A. Degradation of the fabric due to heat, age, or physical use
• B. A type of radiation packaging
• C. Chemical passing through the fabric at the molecular level
• D. A DOT hazard class

Answer: (C)

Permeation is the movement of a chemical through a barrier material at the molecular level. It typically happens in stages: the chemical is absorbed into the outer surface of the fabric, diffuses through the material, and then desorbs on the inner surface. This process can occur without visible damage to the fabric, and it’s different from degradation (where the material itself is damaged by heat, age, or wear) or from other concepts like packaging type or hazard classifications. So the best description is that a chemical passes through the fabric at the molecular level.