Low-Expansion Coefficient Table & Kitchen Glassware

Classification under 7013.42 requires demonstrating that the glass has a linear coefficient of thermal expansion not exceeding 5×10⁻⁶ per Kelvin in the 0–300°C range. Importers should obtain a manufacturer's material specification sheet or third-party laboratory test report confirming this property. Without such documentation, CBP may reclassify the goods under the residual 7013.49 heading.

The pressed-and-toughened subheading (7013421000) is a distinct 10-digit line with its own rate, separate from the value-banded lines for other low-expansion kitchen glassware. Importers should verify the manufacturing process — pressing followed by thermal toughening — is accurately described on entry documentation, as the duty rate may differ from the value-band lines.