## Facts

- Airflow Technology, Inc. imported “Sperifilt,” a multilayer nonwoven polyester filter medium, thermally bonded and impregnated with a tackifying substance.
- Sperifilt was used in industrial paint spray booths to remove dust and particles from circulating air, trapping progressively smaller particles through denser layers.
- Customs classified Sperifilt under HTSUS subheading 5911.40.00 as “straining cloth of a kind used in oil presses or the like.”
- Airflow protested, asserting Sperifilt should be classified under HTSUS heading 5603 (nonwovens), whose Explanatory Notes include sheets for filtering liquids or air.
- The Court of International Trade granted summary judgment to the United States, treating “straining cloth” as synonymous with “filter cloth,” finding both provisions applicable, and selecting 5911.40.00 as more specific.
- Airflow appealed to the Federal Circuit.

## Issues

1. Whether HTSUS subheading 5911.40.00 covers nonwoven media used exclusively for air filtration, or is limited by the phrase “of a kind used in oil presses or the like.”
2. Whether Explanatory Notes referencing “straining cloths for industrial dust-collecting systems” can expand the scope of subheading 5911.40.00 beyond the statutory text.
3. Whether the Court of International Trade properly applied the rule of relative specificity after concluding both heading 5603 and subheading 5911.40.00 described the merchandise.

## Decision

- The Federal Circuit reversed the Court of International Trade and remanded.
- The court held that the qualifier “of a kind used in oil presses or the like” is a limiting requirement tied to liquid-solid separation by pressing, not a broad reference to filtration generally.
- Because Sperifilt was engineered and used for air filtration rather than pressing-related liquid-solid separation, it did not fall within subheading 5911.40.00.
- The court ruled that Explanatory Notes may inform interpretation but cannot broaden a heading or subheading beyond the statute’s text.
- The court found the relative-specificity analysis inapplicable once subheading 5911.40.00 was correctly construed as not covering the goods.

## Legal Principles

- In tariff classification, qualifying statutory language (e.g., “of a kind used in …”) must be given effect as an independent limitation on scope.
- Explanatory Notes are persuasive interpretive aids but are not binding and cannot enlarge tariff language that is narrower on its face.
- The rule of relative specificity applies only after determining that competing provisions each, as properly interpreted, cover the merchandise.

## Conclusion

The Federal Circuit held that HTSUS subheading 5911.40.00 is limited to straining cloth used in oil presses or similar pressing operations that separate solids from liquids, and it does not reach nonwoven media used solely for air filtration; the judgment upholding Customs’ 5911.40.00 classification was reversed and the case remanded.


Airflow Tech., Inc. v. United States, 524 F.3d 1287 (Fed. Cir. 2008)