Collapse to view only § 28.426 - Strict Good Ordinary Spotted Color.

Official Cotton Standards of the United States for Length of Staple

§ 28.301 - Measurement: humidity; temperature.

The length of staple of any cotton shall be the normal length by measurement, without regard to quality or value, of a typical portion of its fibers under a relative humidity of the atmosphere of 65 percent and a temperature of 70 °F.

§ 28.302 - Terms of designation.

The length of staple of any cotton shall be designated by that one of the following terms which expresses its measurement in inches and fractions of an inch in accordance with § 28.301:

“Below 13/16; 7/8; 29/32; 15/16; 31/32; 1; 1 1/32; 1 1/16; 1 3/32; 1 1/8; 1 5/32; 1 3/16; 1 7/32; 1 1/4; 1 9/32; 1 5/16; 1 11/32; 1 3/8; 1 13/32; 1 7/16; 1 15/32; 1 1/2; 1 17/32; 1 9/16; 1 19/32; 1 5/8; 1 21/32; 1 11/16; 1 23/32; 1 3/4; and upward in like manner in gradations of thirty-seconds, disregarding any fraction less than a thirty-second.”

§ 28.303 - Standards for length of staple for American upland cotton.

(a) Effective July 12, 1985, standards for the lengths of staple of American upland cotton shall be measurements as determined by the Suter-Webb Duplex Cotton Fiber Sorter in accordance with the test method prescribed in paragraph (c) of this section. Ranges for each official staple length are shown in the table below. Staple standards exceeding 1 1/4 inches, in graduations of thirty-second inches, will be expressed in increments of .041 inches.

[In inches]

Staple length Upper quartile length range 13/16.827-.847 7/8.909-.929 29/32.950-.970 15/16.990-1.010 31/321.031-1.051 11.072-1.092 1 1/321.113-1.133 1 1/161.154-1.174 1 3/321.195-1.215 1 1/81.236-1.256 1 5/321.277-1.297 1 3/161.318-1.338 1 7/321.359-1.379 1 1/41.400-1.420

(b) Cotton selected for the preparation of practical forms of staple standards shall, to the extent practicable, measure at the mid-point of the appropriate staple range indicated in paragraph (a) of this section.

(c) Length measurements shall be performed in accordance with the “Standard Test Method for Length and Length Distribution of Cotton Fibers (Array Method), ANSI/ASTM D 1440-77 (1982), which is incorporated by reference pursuant to the provisions of 5 U.S.C. 552(a). This standard test method has been adopted by the American Society for Testing and Materials (ASTM) and approved as an American National Standard by the American National Standards Institute. It is published in the “Annual Book of ASTM Standards,” Part 33, volume 07.02. Copies of the ASTM book and copies of ASTM standard D 1440-77 as a separate publication may be obtained from ASTM, Customer Service, 1916 Race Street, Philadelphia, PA 19103. A copy of the ASTM standard test method is also on file at the Office of the Federal Register. A notice of any change in the ASTM standard test method cited herein will be published in the Federal Register.

[49 span 28391, July 12, 1984]

§ 28.304 - Original representation of American Pima cotton staple lengths.

The following lengths of American Pima staple are represented by a quantity of cotton in the custody of the United States Department of Agriculture suitably contained and marked “Original Representation of Official Cotton Standards of the United States” followed in each instance by the name of growth, appropriate designation for staple length, and the effective date.

Staple length (inches) Effective date 1 5/16Aug. 1, 1961. 1 3/8Aug. 10, 1943. 1 7/16Aug. 10, 1943. 1 1/2Aug. 1, 1929.
[49 FR 28391, July 12, 1984]

§ 28.306 - Over 13/16 inch staple.

Cotton which is more than thirteen-sixteenths of an inch in length of staple but is not exactly one of the measurements specified in § 28.302, shall be designated by that one of such measurements which comes nearest under its true measurement.

[22 FR 10930, Dec. 28, 1957. Redesignated at 49 FR 28391, July 12, 1984]

§ 28.307 - Bale of different staple lengths.

Whenever the length of staple of cotton taken from one part of a bale is different from that taken from another part of the same bale, the length of staple of the cotton in such bale shall be that of the part which is the shorter.

[22 FR 10930, Dec. 28, 1957. Redesignated at 49 FR 28391, July 12, 1984]

Official Cotton Standards of the United States for the Color Grade of American Upland Cotton

white cotton

§ 28.401 - Good Middling Color.

Good Middling Color is color which is within the range represented by a set of samples in the custody of the United States Department of Agriculture in a container marked “Original Official Cotton Standards of the United States, American Upland, Good Middling, effective July 1, 1987.”

§ 28.402 - Strict Middling Color.

Strict Middling Color is color which is within the range represented by a set of samples in the custody of the United States Department of Agriculture in a container marked “Original Official Cotton Standards of the United States, American Upland, Strict Middling, effective July 1, 1987.”

§ 28.403 - Middling Color.

Middling Color is color which is within the range represented by a set of samples in the custody of the United States Department of Agriculture in a container marked “Original Official Cotton Standards of the United States, American Upland, Middling, effective July 1, 1987.”

§ 28.404 - Strict Low Middling Color.

Strict Low Middling Color is color which is within the range represented by a set of samples in the custody of the United States Department of Agriculture in a container marked “Original Official Cotton Standards of the United States, American Upland, Strict Low Middling, effective July 1, 1987.”

§ 28.405 - Low Middling Color.

Low Middling Color is color which is within the range represented by a set of samples in the custody of the United States Department of Agriculture in a container marked “Original Official Cotton Standards of the United States, American Upland, Low Middling, effective July 1, 1987.”

§ 28.406 - Strict Good Ordinary Color.

Strict Good Ordinary Color is color which is within the range represented by a set of samples in the custody of the United States Department of Agriculture in a container marked “Original Official Cotton Standards of the United States, American Upland, Strict Good Ordinary, effective July 1, 1987.”

§ 28.407 - Good Ordinary Color.

Good Ordinary Color is color which is within the range represented by a set of samples in the custody of the United States Department of Agriculture in a container marked “Original Official Cotton Standards of the United States, American Upland, Good Ordinary, effective July 1, 1987.”

Light Spotted Cotton

§ 28.411 - Good Middling Light Spotted Color.

Good Middling Light Spotted Color is color which in spot or color, or both, is between Good Middling Color and Good Middling Spotted Color.

§ 28.412 - Strict Middling Light Spotted Color.

Strict Middling Light Spotted Color is color which in spot or color, or both, is between Strict Middling Color and Strict Middling Spotted Color.

§ 28.413 - Middling Light Spotted Color.

Middling Light Spotted Color is color which in spot or color, or both, is between Middling Color and Middling Spotted Color.

§ 28.414 - Strict Low Middling Light Spotted Color.

Strict Low Middling Light Spotted Color is color which in spot or color, or both, is between Strict Low Middling Color and Strict Low Middling Spotted Color.

§ 28.415 - Low Middling Light Spotted Color.

Low Middling Light Spotted Color is color which in spot or color, or both, is between Low Middling Color and Low Middling Spotted Color.

§ 28.416 - Strict Good Ordinary Light Spotted Color.

Strict Good Ordinary Light Spotted Color is color which in spot or color, or both, is between Strict Good Ordinary Color and Strict Good Ordinary Spotted Color.

Spotted Cotton

§ 28.421 - Good Middling Spotted Color.

Good Middling Spotted Color is color which is better than Strict Middling Spotted Color.

§ 28.422 - Strict Middling Spotted Color.

Strict Middling Spotted Color is color which is within the range represented by a set of samples in the custody of the United States Department of Agriculture in a container marked “Original Official Cotton Standards of the United States, American Upland, Strict Middling Spotted, effective July 1, 1987.”

§ 28.423 - Middling Spotted Color.

Middling Spotted Color is color which is within the range represented by a set of samples in the custody of the United States Department of Agriculture in a container marked “Original Official Cotton Standards of the United States, American Upland, Middling Spotted, effective July 1, 1987.”

§ 28.424 - Strict Low Middling Spotted Color.

Strict Low Middling Spotted Color is color which is within the range represented by a set of samples in the custody of the United States Department of Agriculture in a container marked “Original Official Cotton Standards of the United States, American Upland, Strict Low Middling Spotted, effective July 1, 1987.”

§ 28.425 - Low Middling Spotted Color.

Low Middling Spotted Color is color which is within the range represented by a set of samples in the custody of the United States Department of Agriculture in a container marked “Original Official Cotton Standards of the United States, American Upland, Low Middling Spotted, effective July 1, 1987.”

§ 28.426 - Strict Good Ordinary Spotted Color.

Strict Good Ordinary Spotted Color is color which is within the range represented by a set of samples in the custody of the United States Department of Agriculture in a container marked “Original Official Cotton Standards of the United States, American Upland, Strict Good Ordinary Spotted, effective July 1, 1987.”

tinged cotton

§ 28.431 - Strict Middling Tinged Color.

Strict Middling Tinged Color is color which is better than Middling Tinged Color.

§ 28.432 - Middling Tinged Color.

Middling Tinged Color is color which is within the range represented by a set of samples in the custody of the United States Department of Agriculture in a container marked “Original Official Cotton Standards of the United States, American Upland, Middling Tinged, effective July 1, 1987.”

§ 28.433 - Strict Low Middling Tinged Color.

Strict Low Middling Tinged Color is color which is within the range represented by a set of samples in the custody of the United States Department of Agriculture in a container marked “Original Official Cotton Standards of the United States, American Upland, Strict Low Middling Tinged, effective July 1, 1987.”

§ 28.434 - Low Middling Tinged Color.

Low Middling Tinged Color is color which is within the range represented by a set of samples in the custody of the United States Department of Agriculture in a container marked “Original Official Cotton Standards of the United States, American Upland, Low Middling Tinged, effective July 1, 1987.”

yellow stained cotton

§ 28.441 - Strict Middling Yellow Stained Color.

Strict Middling Yellow Stained Color is color which is deeper than that of Strict Middling Tinged Color.

[57 FR 34498, Aug. 5, 1992]

§ 28.442 - Middling Yellow Stained Color.

Middling Yellow Stained Color is American Upland cotton which in color is deeper than Middling Tinged Color.

[57 FR 34498, Aug. 5, 1992]

below color grade cotton

§ 28.451 - Below Color Grade Cotton.

Below color grade cotton is American Upland cotton which is lower in color grade than Good Ordinary, or Strict Good Ordinary Light Spotted, or Strict Good Ordinary Spotted, or Low Middling Tinged, or Middling Yellow Stained. In cotton classification, the official designation for such cotton is Below Color Grade. The term Below Good Ordinary Color, or Below Strict Good Ordinary Light Spotted Color, or Below Strict Good Ordinary Spotted Color, or Below Low Middling Tinged Color, or Below Middling Yellow Stained Color and other additional explanatory terms considered necessary to describe adequately the condition of the cotton may be entered on classification memorandums or certificates.

[57 FR 34498, Aug. 5, 1992]

Official Cotton Standards of the United States for the Leaf Grade of American Upland Cotton

leaf grades

§ 28.461 - Leaf Grade 1.

Leaf Grade 1 is leaf which is within the range represented by a set of samples in the custody of the United States Department of Agriculture in a container marked “Original Official Cotton Standards of the United States, American Upland, Good Middling, effective July 1, 1987.”

§ 28.462 - Leaf Grade 2.

Leaf Grade 2 is leaf which is within the range represented by a set of samples in the custody of the United States Department of Agriculture in a container marked “Original Official Cotton Standards of the United States, American Upland, Strict Middling, effective July 1, 1987.”

§ 28.463 - Leaf Grade 3.

Leaf Grade 3 is leaf which is within the range represented by a set of samples in the custody of the United States Department of Agriculture in a container marked “Original Official Cotton Standards of the United States, American Upland, Middling, effective July 1, 1987.”

§ 28.464 - Leaf Grade 4.

Leaf Grade 4 is leaf which is within the range represented by a set of samples in the custody of the United States Department of Agriculture in a container marked “Original Official Cotton Standards of the United States, American Upland, Strict Low Middling, effective July 1, 1987.”

§ 28.465 - Leaf Grade 5.

Leaf Grade 5 is leaf which is within the range represented by a set of samples in the custody of the United States Department of Agriculture in a container marked “Original Official Cotton Standards of the United States, American Upland, Low Middling, effective July 1, 1987.”

§ 28.466 - Leaf Grade 6.

Leaf Grade 6 is leaf which is within the range represented by a set of samples in the custody of the United States Department of Agriculture in a container marked “Original Official Cotton Standards of the United States, American Upland, Strict Good Ordinary, effective July 1, 1987.”

§ 28.467 - Leaf Grade 7.

Leaf Grade 7 is leaf which is within the range represented by a set of samples in the custody of the United States Department of Agriculture in a container marked “Original Official Cotton Standards of the United States, American Upland, Good Ordinary, effective July 1, 1987.”

below leaf grade cotton

§ 28.471 - Below Leaf Grade Cotton.

Below leaf grade cotton is American Upland cotton which is lower in leaf grade than Leaf Grade 7. In cotton classification, the official designation for such cotton is Below Leaf Grade. Other additional explanatory terms considered necessary to describe adequately the condition of the cotton may be entered on classification memorandums or certificates.

[57 FR 34499, Aug. 5, 1992]

general

§ 28.480 - General.

(a) American Upland cotton which in color is within the range of the color standards established in this part shall be designated according to the color standard irrespective of the leaf content. American Upland cotton which in leaf is within the leaf standards established in this part shall be designated according to the leaf standard irrespective of the color.

(b) The term preparation is used to describe the degree of smoothness or roughness with which cotton is ginned and the relative neppiness or nappiness of the ginned lint. Normal preparation for any color grade of American Upland cotton for which there is a physical color standard shall be that found in the physical color standard. Normal preparation for any color grade of American Upland cotton for which there is a descriptive color standard shall be that found in the physical standards for color used to define the descriptive color grade. Explanatory terms considered necessary to adequately describe the preparation of cotton may be entered on classification memorandums or certificates.

[57 FR 34499, Aug. 5, 1992]

§ 28.481 - Alternate title for standards.

Since these standards have been agreed upon and accepted by the leading European cotton associations and exchanges, they may also be termed and referred to as the “Universal Standards for American Cotton.”

[24 FR 5171, June 25, 1959]

§ 28.482 - United States Cotton Futures Act.

The cotton standards contained in § 28.301 through § 28.603 of this part shall be effective for purposes of the United States Cotton Futures Act (7 U.S.C. 15b) and the regulations thereunder (7 CFR part 27).

[45 FR 46783, July 11, 1980]

Official Cotton Standards of the United States for the ColorGrade of American Pima Cotton

§ 28.501 - Color Grade No. 1.

Color grade No. 1 shall be American Pima cotton which in color is within the range represented by a set of samples in the custody of the U.S. Department of Agriculture in a container marked “Original Official Cotton Standards of the United States, American Pima, Color Grade No. 1, effective July 1, 1986.”

[65 FR 36600, June 9, 2000]

§ 28.502 - Color Grade No. 2.

Color grade No. 2 shall be American Pima cotton which in color is within the range represented by a set of samples in the custody of the U.S. Department of Agriculture in a container marked “Original Official Cotton Standards of the United States, American Pima, Color Grade No. 2, effective July 1, 1986.”

[65 FR 36600, June 9, 2000]

§ 28.503 - Color Grade No. 3.

Color grade No. 3 shall be American Pima cotton which in color is within the range represented by a set of samples in the custody of the U.S. Department of Agriculture in a container marked “Original Official Cotton Standards of the United States, American Pima, Color Grade No. 3, effective July 1, 1986.”

[65 FR 36600, June 9, 2000]

§ 28.504 - Color Grade No. 4.

Color grade No. 4 shall be American Pima cotton which in color is within the range represented by a set of samples in the custody of the U.S. Department of Agriculture in a container marked “Original Official Cotton Standards of the United States, American Pima, Color Grade No. 4, effective July 1, 1986.”

[65 FR 36600, June 9, 2000]

§ 28.505 - Color Grade No. 5.

Color grade No. 5 shall be American Pima cotton which in color is within the range represented by a set of samples in the custody of the U.S. Department of Agriculture in a container marked “Original Official Cotton Standards of the United States, American Pima, Color Grade No. 5, effective July 1, 1986.”

[65 FR 36600, June 9, 2000]

§ 28.506 - Color Grade No. 6.

Color grade No. 6 shall be American Pima cotton which in color is within the range represented by a set of samples in the custody of the U.S. Department of Agriculture in a container marked “Original Official Cotton Standards of the United States, American Pima, Color Grade No. 6, effective July 1, 1986.”

[65 FR 36600, June 9, 2000]

§ 28.507 - Color Grade No. 7.

American Pima cotton which in color is inferior to Color Grade No. 6 shall be designated as “Color Grade No. 7.”

[65 FR 36600, June 9, 2000]

§§ 28.508-28.510 - §[Reserved]

Official Cotton Standards of the United States for the Leaf Grade of American Pima Cotton

§ 28.511 - Leaf Grade No. 1.

Leaf grade No. 1 shall be American Pima cotton which in leaf is within the range represented by a set of samples in the custody of the U.S. Department of Agriculture in a container marked “Original Official Cotton Standards of the United States, American Pima, Leaf Grade No. 1, effective July 1, 1986.”

[65 FR 36601, June 9, 2000]

§ 28.512 - Leaf Grade No. 2.

Leaf grade No. 2 shall be American Pima cotton which in leaf is within the range represented by a set of samples in the custody of the U.S. Department of Agriculture in a container marked “Original Official Cotton Standards of the United States, American Pima, Leaf Grade No. 2, effective July 1, 1986.”

[65 FR 36601, June 9, 2000]

§ 28.513 - Leaf Grade No. 3.

Leaf grade No. 3 shall be American Pima cotton which in leaf is within the range represented by a set of samples in the custody of the U.S. Department of Agriculture in a container marked “Original Official Cotton Standards of the United States, American Pima, Leaf Grade No. 3, effective July 1, 1986.”

[65 FR 36601, June 9, 2000]

§ 28.514 - Leaf Grade No. 4.

Leaf grade No. 4 shall be American Pima cotton which in leaf is within the range represented by a set of samples in the custody of the U.S. Department of Agriculture in a container marked “Original Official Cotton Standards of the United States, American Pima, Leaf Grade No. 4, effective July 1, 2001.”

[65 FR 36601, June 9, 2000]

§ 28.515 - Leaf Grade No. 5.

Leaf grade No. 5 shall be American Pima cotton which in leaf is within the range represented by a set of samples in the custody of the U.S. Department of Agriculture in a container marked “Original Official Cotton Standards of the United States, American Pima, Leaf Grade No. 5, effective July 1, 2001.”

[65 FR 36601, June 9, 2000]

§ 28.516 - Leaf Grade No. 6.

Leaf grade No. 6 shall be American Pima cotton which in leaf is within the range represented by a set of samples in the custody of the U.S. Department of Agriculture in a container marked “Original Official Cotton Standards of the United States, American Pima, Leaf Grade No. 6, effective July 1, 2001.”

[65 FR 36601, June 9, 2000]

§ 28.517 - Leaf Grade No. 7.

American Pima cotton which in leaf is inferior to Leaf Grade No. 6 shall be designated as “Leaf Grade No. 7.”

[65 FR 36601, June 9, 2000]

Application of Standards and Explanatory Terms

§ 28.521 - Application of color and leaf grade standards.

American Pima cotton which in color is within the range of the color standards established in this part shall be designated according to the color standard irrespective of the leaf content. American Pima cotton which in leaf is within the range of the leaf standards established in this part shall be designated according to the leaf standard irrespective of the color content.

[65 FR 36601, June 9, 2000]

§ 28.522 - Explanatory terms.

(a) The term preparation is used to describe the degree of smoothness or roughness of the ginned lint. Normal preparation for any color grade of American Pima cotton for which there is a physical color standard shall be that found in the physical color standard. If the preparation is other than normal, it shall be entered on the classification record.

(b) Explanatory terms considered necessary to adequately describe the presence of preparation, spindle twist, and extraneous matter such as bark, grass, seed coat fragments, oil, etc. in the sample, shall be part of the classification record.

[65 FR 36601, June 9, 2000]

Symbols and Code Numbers Used in Recording Cotton Classification

§ 28.525 - Symbols and code numbers.

For administrative convenience, the symbols and code numbers prescribed in this section may be used in lieu of cotton grade names and staple length designations in inches.

(a) Symbols and Code numbers used for Color Grades of American Upland Cotton.

Color grade Symbol Code No. Good MiddlingGM11 Strict MiddlingSM21 MiddlingMid31 Strict Low MiddlingSLM41 Low MiddlingLM51 Strict Good OrdinarySGO61 Good OrdinaryGO71 Good Middling Light SpottedGM Lt SP12 Strict Middling Light SpottedSM Lt Sp22 Middling Light SpottedMid Lt Sp32 Strict Low Middling Light SpottedSLM Lt Sp42 Low Middling Light SpottedLM Lt Sp52 Stict Good Ordinary Light SpottedSGO Lt Sp62 Good Middling SpottedGM Sp13 Strict Middling SpottedSM Sp23 Middling SpottedMid Sp33 Strict Low Middling SpottedSLM Sp43 Low Middling SpottedLM Sp53 Strict Good Ordinary SpottedSGO Sp63 Strict Middling TingedSM Tg24 Middling TingedMid Tg34 Strict Low Middling TingedSLM Tg44 Low Middling TingedLM Tg54 Strict Middling Yellow StainedSM YS25 Middling Yellow StainedMid YS35 Below Grade—(Below Good Ordinary)BG81 Below Grade—(Below Strict Good Ordinary Light Spotted)BG82 Below Grade—(Below Strict Good Ordinary Spotted)BG83 Below Grade—(Below Low Middling Tinged)BG84 Below Grade—(Below Middling Yellow Stained)BG85

(b) Symbols and Code Numbers used for Leaf Grades of American Upland Cotton.

Leaf grade Symbol Code No. Leaf Grade 1LG11 Leaf Grade 2LG22 Leaf Grade 3LG33 Leaf Grade 4LG44 Leaf Grade 5LG55 Leaf Grade 6LG66 Leaf Grade 7LG77 Below Leaf GradeBLG8

(c) Symbols and Code Numbers for Color Grades of American Pima Cotton.

Full grade name Symbol Code No. Color Grade No. 1AP C101 Color Grade No. 2AP C202 Color Grade No. 3AP C303 Color Grade No. 4AP C404 Color Grade No. 5AP C505 Color Grade No. 6AP C606 Color Grade No. 7AP C707

(d) Symbols and Code Numbers for Leaf Grades of American Pima Cotton.

Full grade name Symbol Code No. Leaf Grade No. 1AP L11 Leaf Grade No. 2AP L22 Leaf Grade No. 3AP L33 Leaf Grade No. 4AP L44 Leaf Grade No. 5AP L55 Leaf Grade No. 6AP L66 Leaf Grade No. 7AP L77

(e) Code numbers for Length of Staple Designations.

Length of staple—inches Code No. Below 13/1624 13/1626 7/828 29/3229 15/1630 31/3231 132 1 1/3233 1 1/1634 1 3/3235 1 1/836 1 5/3237 1 3/1638 1 7/3239 1 1/440 1 9/3241 1 5/1642 1 11/3243 1 3/844 1 13/3245 1 7/1646 1 15/3247 1 1/248 1 17/3249 1 9/1650 1 19/3251 1 5/852 1 21/3253 1 11/1654 1 23/3255 1 3/456
[32 FR 8760, June 20, 1967, as amended at 50 FR 25198, June 18, 1985; 51 FR 23039, June 25, 1986; 57 FR 34499, Aug. 5, 1992; 65 FR 36601, June 9, 2000]

Official Cotton Standards of the United States for Fiber Fineness and Maturity

§ 28.601 - Official cotton standards for fiber fineness and maturity.

The official cotton standards of the United States for fiber fineness and maturity shall be the measure of such qualities, in combination, provided by air flow instrument tests in terms of micronaire readings in accordance with the procedure specified in § 28.603.

§ 28.602 - Terms of designations.

The fiber fineness and maturity of any cotton shall be designated by the micronaire reading obtained from an air flow instrument test for a specimen of the cotton as determined under § 28.603, e.g., 4.1, 4.2, 4.3, etc. To simplify recording, the decimal point may be omitted, and the micronaire reading recorded as 41, 42, 43, etc.

§ 28.603 - Procedures for air flow tests of micronaire reading.

In determining in terms of micronaire readings, the fiber fineness and maturity, in combination, of cotton, the following procedures shall apply:

(a) Facilities and equipment shall include:

(1) Air flow instrument complete with accessories to measure the fineness and maturity, in combination, of cotton in terms of micronaire reading on the curvilinear scale adopted in September 1950 by the Department of Agriculture, or its equivalent.

(2) A suitable supply of compressed air filtered to remove moisture and other impurities.

(3) Balance or scales suitable for accurately weighing the specimens required for the particular instrument.

(4) International Calibration Cotton Standards with established micronaire reading values for calibration of the air flow instrument.

(b) The instrument shall be calibrated each day before routine testing begins, as follows:

(1) The air shall be allowed to flow through the instrument until the indicator stabilizes.

(2) Specimens from at least two of the calibration cottons shall be tested to insure proper calibration of the instrument. The instrument shall be considered in calibration if the values obtained on the test specimens agree with the established values of the calibration cottons within 0.1 micronaire reading.

(c) Testing of the cotton specimen shall be performed as follows:

(1) Approximately the same amount of cotton shall be taken from each side of the sample for a test specimen. The weight of the test specimen shall be that weight prescribed for the air flow instrument being used.

(2) The weighed specimen shall be tested in a properly calibrated instrument.

(3) The specimen shall be inserted into the specimen holder of the instrument so that the mass of fibers is well distributed within the specimen holder.

(4) The air shall then be allowed to flow through the specimen in accordance with the method of operation of the instrument.

(5) The position of the instrument indicator shall be determined to the nearest 0.1 micronaire reading when it becomes stable.

(d) The accuracy of the instrument shall be checked at least every 2 hours during operation by testing appropriate calibration cottons. If the value obtained on a specimen from the calibration cotton is outside the established limits of 0.1 micronaire reading, or when successive readings show the results to be within the established limits, but consistently high or low, the instrument and technique shall be thoroughly checked to remedy the discrepancies. Additional tests using calibration cottons shall be made until acceptable results are obtained before routine testing is resumed.