Analysis of Standard for Fuzzing and Pilling Propensity of Fabrics: Random Rolling Method

On June 19, 2009, the National Technical Committee on Textiles of Standardization Administration of China issued GB/T 4802.4—2009, *Textiles—Determination of fabric propensity to surface fuzzing and to pilling—Part 4: Random tumble method* (hereinafter referred to as “this Standard”), which came into effect on February 1, 2010. This Standard was formulated in response to the requirement by the Standardization Division of the General Administration of Quality Supervision, Inspection and Quarantine (AQSIQ) to earnestly incorporate international standards and improve domestic ones; it adopts relevant content from ASTM D 3512-07, *Standard Test Method for Pilling Resistance and Other Related Surface Changes of Textile Fabrics: Random Tumble Pilling Tester*. The testing principle involves using a random tumble pilling tester to cause fabric specimens to tumble and rub randomly within a cylindrical chamber lined with cork and containing a small amount of short gray cotton fibers; the fabric’s fuzzing and pilling performance is then assessed and described under specified lighting conditions. This Standard represents the fourth method for determining the fuzzing and pilling performance of textiles. Compared to the other three methods, this approach simulates fabric performance in harsher environments—such as areas with strong winds or workplaces characterized by dust, impurities, and frequent contact or friction with external objects.

In the more than six months since the Standard’s implementation, testing personnel have identified certain issues and shortcomings in its practical application. This paper analyzes these issues through experimental testing, aiming to draw the attention of others using the Standard and hoping that relevant experts will further verify the findings and propose improvements.

Regarding the grey short-staple cotton

This standard lacks explicit requirements regarding the grey short cotton fibers, leaving testing personnel without clear guidance during the procedure. The quality of these fibers affects both their adhesion to the fabric and the resulting pilling appearance; furthermore, their purpose is not to alter the specimen’s actual pilling propensity, but rather to enhance the visual clarity of the pilling, thereby facilitating accurate rating. In contrast, ASTM D 3512-07 specifies precise requirements for these fibers: a linear density of 4301 tex and the use of Upland cotton (or an equivalent type).

As for the Preparation of Test Specimens

This standard does not explicitly specify the method for preparing test specimens; sampling may be performed with one edge parallel to the warp (wale) or weft (course) direction, at a 45° angle to these directions, or via other methods. Conventional practice often leads testers to cut specimens with an edge parallel to the warp or weft; however, with loosely structured woven fabrics, this approach can cause the edges to unravel during testing, thereby interfering with the procedure. Sampling at a 45° angle to the warp or weft directions avoids this issue. ASTM D 3512-07 explicitly mandates this 45° sampling orientation.

About Test Methods

Regarding the test procedure, this standard specifies that specimens from the same sample must be tested in separate test chambers; specifically, three specimens taken from the same laboratory sample are placed into test chambers—one specimen per chamber—along with approximately 25 mg of gray cotton sliver (6 mm in length). When testing is conducted according to this requirement, it is observed that specimens frequently become entangled with the impeller (preventing tumbling) or get stuck at the bottom or on the sides of the chamber. In contrast, when the ASTM D 3512-07 method is used—placing three specimens from the same laboratory sample into a single chamber simultaneously—such issues rarely occur (typically arising no more than two or three times per test run). Furthermore, normal operation can usually be resumed simply by nudging the chamber lid or stopping and restarting the machine. The test performance is satisfactory, and the process proceeds smoothly even when testing four laboratory samples simultaneously (using the four-chamber equipment manufactured by FYI, currently considered the industry standard).

To compare the two test methods, the following experiment was designed: three types of samples—combed wool woven fabric, semi-combed wool woven fabric, and 60/40 polyester-cotton knitted fabric—were selected and tested for 30 minutes using two different configurations: one specimen per chamber versus three specimens per chamber.

The results showed that when a single specimen was placed in a chamber (with three specimens tested in parallel across separate chambers), the specimens frequently became entangled with the impeller or stuck to the chamber walls or bottom, often within less than one minute of testing. Conversely, when three specimens were placed together in a single chamber, the testing process proceeded smoothly for all three fabric types. This is because placing three specimens in one chamber facilitates interaction between the samples and utilizes the available space more effectively; the resulting fuzzing and pilling process generates increased friction, better simulating actual wear conditions. This approach yields superior test results and aligns with the ASTM D 3512-07 method. Test results are presented in Table 1. Additionally, the same three specimens were tested using the circular locus method (780 cN pressure, 600 cycles), and all yielded a rating of Grade 3. Thus, it is evident that the second testing configuration produces better results.

Table 1 Pilling grades of three fabrics tested by different methods

	One specimen per test chamber: Pilling grade	Three specimens per test chamber: Pilling grade
Combed wool woven fabric	4	3.5
Semi-worsted wool woven fabric	4	3
60/40 Polyester/Cotton knitted fabric	4	3.5

Recommendations

In summary, the following modifications to this standard are recommended: (1) clearly specify the requirements for “grey short cotton” based on further analysis and confirmation by relevant experts; (2) explicitly specify a sampling method oriented at a 45° angle to the warp (longitudinal) or weft (transverse) direction; and (3) revise the testing procedure so that three specimens from the same laboratory sample are tested simultaneously in a single test chamber, rather than testing specimens from the same sample in separate test chambers.

Reference: China Fiber Inspection (2011.04)— “Analysis of Standard for Fuzzing and Pilling Propensity of Fabrics: Random Rolling Method” .If any copyright infringement is detected, please contact us.