Tariff classification turns on principal function, so refrigeration machinery was classified under Heading 84.15, not cooling equipment.

Tariff classification depends on the principal function of the imported machinery as shown by its construction and working, not on the purchaser's intended end use. The equipment contained the essential refrigeration cycle and cooled air by lowering its temperature below the dew point, so its main function was refrigeration rather than a mere simple temperature change. On that basis, the Explanatory Notes excluded it from Heading 84.17 for machinery where cooling is only secondary, and the goods were classified under Heading 84.15 instead.

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Issues: Whether the imported machinery was classifiable as air-conditioning equipment under Heading 84.15 of the Customs Tariff or as machinery falling under Heading 84.17(1).

Analysis: The classification turned on the principal function of the machine as disclosed by its construction and working, not on the user's intended end use. The machinery contained the essential refrigeration cycle components and cooled air by lowering its temperature below the dew point, thereby removing moisture. The Explanatory Notes to the tariff showed that Heading 84.17 covered machinery designed to subject materials to heating or cooling for a simple change in temperature, while excluding machinery in which cooling was only secondary to the main function. Since the primary purpose of the imported equipment was to refrigerate the air, the exclusion from Heading 84.17 applied and the respondent's reliance on the air-drying aspect did not alter the proper classification.

Conclusion: The machinery was classifiable under Heading 84.15 and not under Heading 84.17(1); the appeal succeeded and the restoration of the Assistant Collector's order followed.

Ratio Decidendi: For tariff classification, the decisive factor is the principal function of the goods as understood from their construction and working, and not the purchaser's intended use; where cooling is the primary function, the goods are excluded from a heading meant for simple temperature change.

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