Machine parts classification: specially fabricated rupture discs were held classifiable with the plant machinery, not as steel articles.

Rupture discs specially fabricated for a sulphuric acid plant's combustion furnace were treated as integral protective parts of the machinery, not as steel articles classifiable by material alone. Applying Note 2 to Section XVI, parts suitable solely or principally for use with a particular machine are classified with that machine, and goods of the kind described in Chapter 84 are to be placed in their respective headings. On that basis, the discs were held classifiable under Heading 84.17(I) rather than Heading 73.33/40.

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Issues: Whether rupture discs used in sulphuric acid plant explosion flaps were classifiable under Heading 84.17(I) of the Customs Tariff rather than under Heading 73.33/40.

Analysis: The discs were specially fabricated for the combustion furnace of the acid plant, were fitted to the plant with necessary dimensions and bolt holes, and functioned as an integral protective component of the machinery. Applying Note 2 to Section XVI, parts suitable for use solely or principally with a particular machine are to be classified with that machine, and goods of a kind described in Chapter 84 are to be classified in their respective headings. On that basis, the discs were treated as parts of plant machinery and not as steel articles classifiable by material alone.

Conclusion: The rupture discs were correctly classifiable under Heading 84.17(I), and the revenue's appeal failed.

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