1.1 This test method covers the determination of the breaking strength of yarn in skein form. The observed breaking strength is expressed in units of force, and equations are provided to convert breaking strength to skein breaking tenacity and to skein break factor.

Note 1—For the determination of the breaking strength and elongation of yarn by the single strand method, refer to Test Method D2256.

1.2 This test method is applicable to spun yarns, either single or plied, composed of any fiber or blend of fibers, but is not suitable for yarns which stretch more than 5% when the tension is increased from 2.5 to 7.5 mN/tex or 0.03 to 0.08 gf/denier.

1.3 This test method provides three options based on the perimeter of the reel, the number of wraps in the skein, and the machine speed or time-to-break.

1.3.1 Option 1—Eighty, forty, or twenty turns on a 1.50-m or 1.5-yd reel, broken at 300 mm/min or 12 in./min.

1.3.2 Option 2—Fifty turns on a 1.00-m or 1-yd reel, broken at 300 mm/min or 12 in./min.

1.3.3 Option 3—Fifty turns on a 1-m reel, broken in 20 s.

Note 2—Option 1 is in general use in the United States, Option 2 is used for woolen yarns, and Option 3 has been proposed in the International Standards Organization (ISO) for international use.

Note 3—Metric reels are available with 1 and 1.125-m circumferences. Data from the two reels will be about 1% different (see 5.6). ISO uses a 1-m circumference reel.

1.4 This test method is frequently combined with the determination of linear density carried out on the same skeins. Special precautions for reeling such skeins are noted.

1.5 Where appropriate, this test method states all requirements in SI units. The traditional units are inch-pound and are exact values.

1.6 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use