Tariff classification turns on function, not material, for a complete combustion chamber assembly used in chemical processing.

An imported graphite combustion chamber assembly was treated as a complete equipment unit for burning hydrogen with chlorine to produce hydrochloric acid, so classification turned on its function and intended use rather than its material composition. Chapter Note 1(a) to Chapter 84 did not displace classification where the goods were not mere mineral articles or spare parts but a complete machinery or plant item. On that basis, the article was held classifiable under Heading 84.17 of the Customs Tariff Act, 1975 and not under Heading 68.01/16.

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Issues: Whether the imported combustion chamber unit, made of graphite and consisting of upper shell, intermediate shell, lower shell and fittings, was classifiable under Heading 84.17 of the Customs Tariff Act, 1975 as machinery, plant or similar equipment, or under Heading 68.01/16 of the Customs Tariff Act, 1975 as articles of stone or other mineral substances.

Analysis: The imported goods were found to constitute a complete unit or equipment designed for a specific process of burning hydrogen with chlorine to produce hydrochloric acid. The decisive factor was the function performed by the goods, not merely the material used in their manufacture. Chapter Note 1(a) to Chapter 84 excluded articles falling within Chapter 68, but that exclusion was held not to govern a complete machinery item whose proper classification depended on its use and character as plant or equipment. The record also showed that the goods were treated as a combustion chamber assembly and not as mere spare parts.

Conclusion: The goods were correctly classifiable under Heading 84.17 of the Customs Tariff Act, 1975 and not under Heading 68.01/16 of the Customs Tariff Act, 1975.

Ratio Decidendi: Where an imported article is a complete machinery or plant unit, tariff classification is governed primarily by its function and intended use rather than the material from which it is made.

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