In weft pile fabrics, the pile loops are formed by extra weft yarns and may be left uncut (580121/580131) or cut (580122–580123/580132–580133). In warp pile fabrics (580127/580137), the pile is formed by extra warp yarns woven over wires or a second ground. The direction of the pile-forming yarn — warp or weft — and whether it is cut or uncut determines the correct subheading.

Narrow woven fabrics not over 30 cm in width are explicitly excluded from heading 5801 and classified instead under heading 5806. Width measurement of the finished fabric is therefore the first step before assigning a tariff line for any pile or chenille fabric.