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1 Translated English of Chinese Standard: GB/T NATIONAL STANDARD OF THE GB PEOPLE S REPUBLIC OF CHINA lcs W 04 Replacing GB/T Textiles - Bursting Properties of Fabrics - Part 1: Hydraulic Method for Determination of Bursting Strength and Bursting Distension 纺织品织物胀破性能第 1 部分 : 胀破强力和胀破扩张度的测定液压法 (ISO :1999, MOD) Issued on: November 4, 2005 Implemented on: May 1, 2006 Issued by: General Administration for Quality Supervision, Inspection and Quarantine (AQSIQ); Standardization Administration (SAC) of the People s Republic of China. Page 1 of 12

2 Table of Contents 1 Scope Normative References Terms and Definitions Principle Test Specimens Apparatus Conditioning Procedure Calculation and Expression of Results Test Report Appendix A (Informative) Selection of Test Areas Page 2 of 12

3 Foreword GB/T 7742 "Textiles - Bursting Properties of Fabrics" includes the following two parts: Part 1: Hydraulic Method for Determination of Bursting Strength and Bursting Distension; Part 2: Pneumatic Sealing Method for Determination of Bursting Strength and Bursting Distension. This Part is Part 1 of GB/T 7742; it is modified in relation to ISO :1999 "Textiles - Bursting Properties of Fabrics - Part 1: Hydraulic Method for Determination of Bursting Strength and Bursting Distension". This part is redrafted according to ISO :1999; its differences with ISO :1999 are as follows: The quoted GB 6529 "Textiles - Standard Atmospheres for Conditioning and Testing" in normative reference of this Part is established by reference to ISO 139 "Textiles - Standard Atmospheres for Conditioning and Testing"; the quoted GB/T is identical to ISO 10012:2003 and thereby replaces the normative reference ISO :1992 in ISO standard; 6.1.1~6.1.8 of ISO are adjusted as 6.1~6.8 according to the requirements of "Articles may be set only when there are two or above articles in the same level". This Part replaces GB/T "Textiles - Determination of Bursting Strength and Bursting Distension - Diaphragm Method". This Part has made the following technical modifications to GB/T : The standard name is changed to "Textiles - Bursting Properties of Fabrics - Part 1: Hydraulic Method for Determination of Bursting Strength and Bursting Distension"; a comparison description of using two kinds of apparatus is added in the Scope. 5 terms: test area, bursting pressure, diaphragm pressure, bursting height and bursting volume and their definitions are added; the definition of bursting distention is modified. Requirements for apparatus accuracy are added and modified. The bursting pressure is adjusted to ±2% of full scale from ±1%; the bursting height is adjusted to ±1mm from ±0.25mm. Bursting volume accuracy does not exceed ±2% is added; the volume increase rate accuracy is ±10%. Page 3 of 12

4 Textiles - Bursting Properties of Fabrics - Part 1: Hydraulic Method for Determination of Bursting Strength and Bursting Distension 1 Scope This part of GB/T 7742 specifies the hydraulic method of determining textile bursting strength and bursting distension, including two kinds of procedures of determining test specimen bursting property: conditioning and soaking. This Part uses constant rate pump device to apply hydraulic pressure. Pneumatic sealing method is specified in Part 2 of GB/T This Part is applicable to knitted fabric, woven fabrics, nonwovens, laminated fabric and various textiles manufactured from other process. The available data indicate: when the pressure does not exceed 80kPa, the bursting strength results obtained by adopting hydraulic and pneumatic sealing bursting apparatus have no obvious difference. This pressure range includes most of the property levels of ordinary garments. For special textiles with higher requirements for bursting pressure, hydraulic apparatus is more applicable. 2 Normative References The following standards contain the provisions which, through reference of this Part of GB/T 7742, constitute the provisions of this Part. For dated reference, the subsequent amendments (excluding correction) or revisions of these publications do not apply. However, the parties who enter into an agreement according to this Part are encouraged to study whether the latest editions of these documents are applicable. For undated references, the latest edition of the reference document is applicable to this Part. GB 6529 Textiles - Standard Atmospheres for Conditioning and Testing GB/T 6682 Water for Analytical Laboratory Use-Specification and Test Methods (GB/T , neq ISO 3696:1987) GB/T Measurement Management Systems - Requirements for Measurement Processes and Measuring Equipment (GB/T , ISO 10012:2003, IDT) Page 5 of 12

5 Liquid volume required for reaching bursting pressure. 3.8 Time to burst Time required for distending to test specimen breakage. 4 Principle Clamp the test specimen to extendible diaphragm; apply liquid pressure under the diaphragm and make the diaphragm and test specimen distend. Increase the liquid volume at constant speed till the test specimen breaks; measure the bursting strength and bursting distension. 5 Test Specimens Sampling shall be carried out according to product standard requirements or the agreement signed by parties concerned. If there are no requirements in product standard serving as examples, an appropriate method of selecting test area shall be given in Appendix A. The test area shall avoid wrinkles, selvage or area which is unable to represent textiles. Generally, the clamping system used may be subjected to test without cutting the specimen. 6 Apparatus Measurement confirmation of bursting apparatus shall comply with GB/T Bursting apparatus shall meet the following requirements: 6.1 Apparatus shall be possessed of constant volume increase rate in the range of 100cm 3 /min~500cm 3 /min; the accuracy is ±10%. If the apparatus is not equipped with a device adjusting liquid volume, time to burst 20s±5s may be adopted; such situation shall be indicated in the test report. 6.2 When the bursting pressure is larger than 20% of the full scale, its accuracy is ±2% of the full scale. 6.3 When the bursting height is less than 70mm, its accuracy is ±1mm. At the beginning of the test, the zero point of measurement separation shall be capable of being adjusted in order to adapt to test specimen thickness. 6.4 If the bursting volume may be displayed, its accuracy shall not exceed ±2% of the indicating value. Page 7 of 12

6 Note 1: For most textiles, especially knitted fabrics, test area 50cm 2 is applicable. For fabrics possessed of low extensibility (according to experience or trial test), such as industry use textiles, the recommended test area is at least 100cm 2. When conditions are not met or unsuitable, if both sides agree, test area in 6.5 may be used. Note 2: Comparison test shall be performed with the same test areas and the same rate of volume increase. 8.3 Set a constant rate of increase in volume of between 100cm 3 /min and 500cm 3 /min. Or adjust a time to distend a test specimen to burst of (20±5)s using preliminary trials. 8.4 Place the test specimen over the diaphragm so that it lies in a flat tensionless condition, avoiding distortion in its own plane. Clamp it securely in the clamping ring, avoiding damage, to prevent slippage during the test. Place the distension recording device into the measuring position and adjust it to the zero position. Fasten the safety cover in position according to machine requirements. Apply pressure to the test specimen until the fabric bursts. Immediately after burst, reverse the apparatus to starting position. Note bursting pressure and height at burst and/or bursting volume. If the test specimen bursts close to the edge of the clamping device, report this fact. Repeat the test at least four more times at different places on the fabric. The number of test specimens may be increased if agreed mutually. 8.5 Determination of diaphragm pressure With the same test area and rate of increase in volume or time to burst as that employed in the above tests, distend the diaphragm without the presence of a test specimen by an amount equal to the mean height at burst or the mean volume at burst of the test specimen. Note the pressure at this distension of the diaphragm as the "diaphragm pressure". 8.6 Wet test For tests in the wet condition, immerse the test specimen for a period of 1h in Grade 3 water in accordance with GB/T 6682 at a temperature of (20±2) C. For tropical regions, temperature according to GB 6529 may be used. An aqueous solution containing not more than 1g of a nonionic wetting agent per litre may be used instead of Grade 3 water. Immediately after removal of a test specimen from the liquid and briefly placing it on blotting paper to remove excess water, perform the test according to 8.2 to Calculation and Expression of Results Page 9 of 12

7 c) Mean volume at burst (if required); d) The coefficient of variation of the relevant values (if required); e) Relevant confidence interval (if required). Page 11 of 12