Tariff classification of an Ozone Test Chamber turns on its principal testing function, not the residuary machinery heading.

An Ozone Test Chamber used to test rubber resistance to ozone deterioration and cracking was treated as testing apparatus rather than a general machine with an individual function. Product literature and technical features, including monitoring, control and test parameter display, supported classification in Chapter 90. Heading 84.79, as a residuary entry for machines and mechanical appliances not specified elsewhere, was found less appropriate than the headings covering testing apparatus. The goods were therefore held outside Heading 8479.89, with the majority placing them under Heading 9027.80 and a concurring view favouring Heading 9024.80.

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Issues: Whether the imported Ozone Test Chamber was correctly classifiable under Heading 8479.89 of the Customs Tariff or under Heading 9027.80, alternatively Heading 9024.80.

Analysis: The equipment was found to perform more than a mere ozone-generating function and was used to test the resistance of rubber to ozone deterioration and cracking. The product literature and technical material showed that it functioned as testing apparatus with features such as monitoring, control, and test parameter display. Heading 84.79, being a residuary entry for machines and mechanical appliances having individual functions not specified elsewhere, was held to be less appropriate. The competing headings in Chapter 90 covered testing apparatus, and the reasoning also accepted that the nature of the test conducted on rubber brought the goods within the testing category rather than the general machinery category.

Conclusion: The Ozone Test Chamber was not classifiable under Heading 8479.89 and was held to fall under Chapter 90, with the majority placing it under Heading 9027.80 and the concurring opinion treating Heading 9024.80 as the more appropriate classification.

Ratio Decidendi: For tariff classification, the heading specifically covering the principal testing function of the goods prevails over a residuary machinery heading where the article is used as testing apparatus rather than as a general machine with an individual function.

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