4411.94.00.70 - Impregnated with bitumen

This HTS classification, 4411.94.00.70, specifically covers fiberboard of wood or other ligneous materials that are **impregnated with bitumen**. This means the material has undergone a process where bitumen, a tar-like substance derived from petroleum or coal, has been incorporated into its structure. This impregnation typically enhances properties such as water resistance, durability, and fire retardancy. Examples could include certain types of roofing felt or underlayment materials derived from wood fiber and treated with bitumen.

This category is distinguished from its sibling, 4411.94.00.80, which is designated as "Other." While this sibling captures any fiberboard meeting the density and "Other" criteria that isn't specifically impregnated with bitumen, 4411.94.00.70 is precisely for those products where bitumen impregnation is a defining characteristic. The classification hinges on the presence and purpose of the bitumen within the fiberboard.

As this classification represents a leaf node within the HTS, there are no further subcategories. Therefore, the focus for classification under this code rests entirely on accurately identifying the material as fiberboard, confirming its density does not exceed 0.5 g/cm³, and verifying that it has been impregnated with bitumen.