Non-metallic expansion joints are commonly classified in the category of "Other Unlisted Industrial Machine Parts" in international trade and their HS code (Harmonized System code) may be 8481.90.00, but this depends on the specific product details and the classification rules of the individual national customs.

The HS Code is a six-digit international standard commodity classification system used for the classification and tariff collection of goods in global trade. The 8481.90.00 code generally refers to industrial machinery parts, but does not directly and specifically refer to non-metallic expansion joints. Non-metallic expansion joints may be further subdivided under more specific subcategories based on their specific functions, materials, and designs.

Since HS codes may vary depending on the interpretation and application of different countries, it is recommended to consult a professional customs broker or the customs department of the relevant country in the actual import and export business to obtain the most accurate commodity classification and corresponding HS codes, ensuring compliance with local regulations and requirements. At the same time, if the non-metallic expansion joint has a special design or function, a more detailed classification may be required, which will affect the exact number of HS codes.