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HQ 963016

April 3, 2001

CLA-2 RR:CR:GC 963016 BJB


TARIFF NO.: 8544.70.00

David Moser
Corning Cable Systems LLC
800 17th Street, NW
P.O. Box 489
Hickory, NC 28603

RE: Optical Fiber Cable, Individually sheathed fibers.

Dear Mr. Moser:

This is in response to your letter of June 18, 1999, requesting the issuance of a ruling on the tariff classification of “tight buffered” and “loose tube” optical fiber cables, under the Harmonized Tariff Schedule of the United States (HTSUS). Your letter was referred to this office for reply. Corning Cable Systems LLC (formerly Siecor Operations LLC) submitted two sample lengths of optical fiber cable, as well as, explanatory materials. Additional information was obtained from Corning and Siecor internet websites. In preparing this ruling, we also gave consideration to your January 1, and February 8, 2001 responses, to our December 28, 2000 request for further information.


An optical fiber cable is composed of many strands of coated glass optical fibers. Optical fibers are extremely thin strands of ultra-pure glass designed to transmit light signals from a transmitter to a receiver. These light signals represent encoded electrical signals that include video, audio, or data information in any combination.

An optical fiber consists of three main regions. 1) The center region of the fiber is the glass core. This region actually carries the light. The optic core ranges in diameter from 8 microns to 100 microns in the most commonly used fibers. 2) Surrounding the optical fiber core is a region called the cladding. The cladding, typically, is also made of glass and has a diameter of 125 microns or 140 microns. 3) The third region of the optical fiber, includes the acrylate coating that provides protection to the individual optical fibers against microbending and abrasion.

Once light enters a glass fiber, the cladding layer prevents light loss as the beam of light zigzags along, inside, the glass core. Glass fibers can transmit messages or images by having beams of light directed through their cores over very short or very long distances, without significant distortion. The pattern of light waves forms a code that carries a message. At the receiving end, the light beams are converted back into electric current, and decoded. Since light beams are immune to electrical noise and can be carried greater distances before fading, this technology is used heavily in telecommunications.

As the glass fiber comes out of the furnace, it has a highly polished pristine surface with a theoretical strength in the range of 12-20 Giga-Pascals (GPa). To preserve this high strength, polymeric coatings are applied immediately after the drawing. Usually two layers of acrylate coatings are applied to the cladded core: (1) a soft inner acrylate coating adjacent to the fiber to avoid microbending loss, and (2) a hard outer acrylate coating to resist abrasion. The coatings may be ultraviolet (UV) curable acrylates, UV-curable silicones, hot melts, heat-curable silicones or nylons. When dual coatings are applied, the coated fiber diameter is typically within a range of 235 – 250 microns.

Corning provides that it manufactures optical fiber with a core, cladding and a “protective acrylate coating.” Combined, the core, cladding and protective UV dual curable acrylate are approximately 245 microns in diameter. Depending upon the type of optical fiber cable, a varied number of individual optical fibers are grouped in a broad range of buffered tubes, or similar coverings, including different types of insulation, all contained within the cable’s outermost layer or jacket. Corning states that it has “pioneered the development of dual layer acrylate coatings for nearly three decades” with its “CPC” optical fiber coatings. Corning also states that its dual acrylate coatings can “withstand harsh environments,” has “improved handeability” in the field, and “is compatible with all cable designs.” To validate the performance of its dual acrylate coatings, since 1977 to the present, Corning has conducted extensive laboratory and performance testing in field applications. Corning’s dual layer acrylate coating is applied to optical fiber capable of use in all of its loose tube and tight buffer optical fiber cable designs.

The dual acrylate coating provides important protection and structural integrity to the bare glass fibers, and is responsible for each optical fiber’s tensile strength, to the extent that bare glass fibers could not be used without it. Further, the application of dual acrylate coatings/sheathing provides significant protection against abrasion of the optical fibers, enhances tensile strength, and reduces the effects of long-term stress, in particular, exposure to humid environments which can lead to failure due to a phenomenon called “static fatigue.” The dual acrylate coating helps protect the glass fibers against optical loss due to microbending, is resistant to aging and harsh environmental conditions.


Whether Corning’s “loose tube” and “tight buffered” optical fiber cables using dual acrylate coatings and an additional color coating, are classifiable under heading 8544, HTSUS, as “optical fiber cables, made up of individually sheathed fibers,” or under heading 9001, HTSUS, as “[o]ptical fibers and optical fiber bundles; optical fiber cables other than those of heading 8544; . . . [o]ptical fibers, optical fiber bundles and cables . . .”


Classification of merchandise under the HTSUS is in accordance with the General Rules of Interpretation (GRIs). Under GRI 1, HTSUS, goods are to be classified according to the terms of the headings and any relative section or chapter notes, and provided the headings or notes do not require otherwise, according to GRIs 2 through 6.

In understanding the language of the HTSUS, the Harmonized Commodity Description and Coding System Explanatory Notes may be utilized. The Explanatory Notes (ENs), although not dispositive or legally binding, provide a commentary on the scope of each heading of the HTSUS, and are generally indicative of the proper interpretation of these headings. Customs believes the ENs should always be consulted. See T.D. 98-80, 54 Fed. Reg. 35127, 35128 (Aug. 23, 1989).

The HTSUS provisions under consideration are as follows (emphasis added):

8544 Insulated (including enameled or anodized) wire, cable (including coaxial cable) and other insulated electric conductors, whether or not fitted with connectors; optical fiber cables, made up of individually sheathed fibers, whether or not assembled with electric conductors or fitted with connectors:

9001 Optical fibers and optical fiber bundles; optical fiber cables other than those of heading 8544; sheets and plates of polarizing material; lenses (including contact lenses), prisms, mirrors and other optical elements, of any material, unmounted, other than such elements of glass not optically worked:

EN 85.44 states that the heading also covers:

“optical fibre cables, made up of individually sheathed fibres, whether or not assembled with electric conductors or fitted with connectors. The sheaths are usually of different colours to permit identification of the fibres at both ends of the cable. Optical fibre cables are used mainly in telecommunications because their capacity for transmission of data is greater than that of electrical conductors.”

Heading 9001, HTSUS, covers inter alia, “optical fibers and optical fiber bundles: optical fiber cables other than those of heading 8544.” Section XVIII, Chapter 90, Note 1(h), states that “optical fiber cables of heading 8544” are not covered in Chapter 90. Optical fiber cables composed of optical fibers that are not “individually sheathed” would be classifiable under heading 9001. Therefore, the issue to resolve is, whether the instant cables are individually sheathed.

The legal notes and heading texts, as well as the ENs, do not provide a definition of the term: “individually sheathed.” In the absence of such guidance, tariff terms may be construed in accordance with their common and commercial meanings. Nippon Kogasku (USA), Inc., v. United States, 69 CCPA 89, 673 F.2d 380 (1982). Common and commercial meaning may be determined by consulting dictionaries, lexicons, scientific authorities and other reliable resource materials. C.J. Tower & Sons v. United States, 69 CCPA 128, 673 F.2d 1268 (1982).

As a result of technological advances, optical fiber cables may not always be comprised of optical fibers that are covered with the traditional, thick, protective, removable plastic. However, the application of a thin primary inking or coating applied primarily for color-coding, would not constitute a “sheath” for purposes of heading 8544, HTSUS. A “buffered fiber” is the general term used in the optical fiber cable industry to describe “[a]n optical fiber that has a coating over the cladding for protection, increased visibility, and ease of handling.” Communications Standard Dictionary, 3rd Ed., p.98.

Corning asserts that the optical fibers of its “loose tube” optical fiber cable are not “individually sheathed,” but that the optical fibers in its “tight buffered” optical fiber cable, with a thermoplastic buffer of 900 microns in diameter, are “individually sheathed.” Insofar as an individual optical fiber composed of a glass core, cladding, dual acrylate coating, and color coating, which is further individually placed in a thermoplastic buffer, it would be considered “individually sheathed” under heading 8544, HTSUS. We will, however, examine whether only optical fiber individually encased in a thermoplastic covering, measuring 900 microns in diameter, is classifiable as “individually sheathed.”

The strength of an optical fiber is of such fundamental importance that it is subjected to a process called “proof testing.” This testing subjects an optical fiber to levels of controlled “proof stress” reflecting those stresses that it will encounter during manufacture, storage, installation, and service. As a result, an optical fiber’s strength can be quantified. To meet industry standards optical fiber is “proof tested” during its manufacturing process, once the glass core and cladding are drawn, and the dual acrylate is applied. In some cases “proof testing” is performed after an additional color coating is applied. All of the optical fibers used in Corning’s “loose tube” and “tight buffered” optical fiber cables are coated with dual acrylate protective coating (245 microns in diameter), are “proof tested,” and meet or exceed industry standards.

Proof testing not only guarantees that an optical fiber possesses the strength to survive short-term stresses, but it also guarantees that an optical fiber will survive lower residual stress that it may be subjected to during its long service life (sometimes as long as 20-40 years). Proof testing can be performed in-line immediately after the glass optic fiber core and cladding are drawn and coated, or off-line, before the optical fiber is stored. This is significant, because only optical fibers that survive proof testing are used and/or stored, for further packaging into cables.

Corning’s dual acrylate layers are applied to each individual optical fiber. Then a color coating is applied. The initial layer of acrylate is a soft, low-modulus, UV curable acrylate. It provides a cushion-like protection against small bends and external forces that an optical fiber may experience over its active lifetime. The second layer of UV acrylate is a high-modulus, abrasion resistant coating. This layer provides stronger mechanical protection of the glass fiber during handling, cable manufacturing and installation.

The amount of dual acrylate coating applied to Corning’s optical fiber is 62.5 microns thick, and reflects “an industry standard.” Corning has established that its incorporation and application of dual acrylate coatings protect the individual optical fibers from abrasions to the glass core and cladding that could cause short or long-term failures.

All of the optical fibers used in Corning’s “loose tube” and “tight buffered” optical fiber cables are coated with its dual acrylate protective coating. Insofar as the subject optical fiber is individually coated with 62.5 microns of protective dual acrylate (245 microns in diameter), which enhances microbending resistance, improves the ability of an individual optical fiber to be stripped for repairs, and improves the individual optical fiber’s environmental stability, it is our opinion that optical fiber cable composed of this optical fiber and coated with Corning’s combination of dual acrylate and additional thin layer of color coating, would be classifiable as “individually sheathed” under heading 8544, HTSUS. We believe that 62.5 microns of dual acrylate and color coatings do substantially add to the overall protection, security, and reliability of each individual optical fiber, is sufficient and should be considered sheathing.

Heading 9001, HTSUS, provides for optical fibers and optical fiber bundles; optical fiber cables other than those of heading 8544. EN 90.01 states, that this heading covers inter alia, optical fibres and optical fibre bundles, as well as optical fibre cables other than those of heading 8544. Thus, if the subject optical fiber cable is classifiable at heading 8544, it would not be classifiable at heading 9001. EN 90.01(A) describes “Optical fibre cables” classifiable at this heading. They “consist of a sheath containing one or more optical fibre bundles, the fibres of which are not individually sheathed.” Insofar as we have determined that the optical fibers used in Corning’s “loose tube” and “tight buffered” optical fiber cables are, in fact “individually sheathed,” these cables are not classifiable under heading 9001. Further, EN 90.01(A) also states that, “Optical fibres” classifiable under heading 9001, consist of “concentric layers of glass or plastics of different refractive indices[.]” “[T]hose drawn from glass have a very thin coating of plastics, invisible to the naked eye, which renders the fibres less prone to fracture.” The dual acrylate coating and color coating are clearly visible to the naked eye, and are not proportionately “very thin” with respect to the diameter of the core and cladding. Fundamentally, however, Corning’s coating/sheathing protects the individual optical fiber more than by rendering it “less prone to fracture.”

It is not our view, that every coating, buffering, jacket, covering, or sheathing, merely because it is called a “sheathing,” or has some of the qualities exhibited by Corning’s dual protective coating, affords an optical fiber sufficient protection for it to be classifiable under heading 8544, as “individually sheathed.” However, in this case, Corning has adequately demonstrated that its combination of approximately 62.5 microns of dual acrylate coating and additional layer of coloring does provide substantial sheathing protection to the individual optical fibers in its optical fiber cable. Therefore, at GRI 1, we find that the merchandise is classifiable under heading 8544, HTSUS. See HQ Rulings 962322, 962445, 963213, 963256, and 964632 of this date for similar rulings.


The subject Corning “loose tube” and “tight buffered” optical fiber cable with individually sheathed fibers are classifiable under subheading 8544.70.00, HTSUS, which provides for: “[i]nsulated (including enameled or anodized) wire, cable (including coaxial cable) and other insulated electric conductors, whether or not fitted with connectors; optical fiber cables, made up of individually sheathed fibers, whether or not assembled with electric conductors or fitted with connectors: Optical fiber cables.”


John Durant, Director

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