ASTM D5034 and ISO 13934-2 Grab Test on Textiles
The grab test is an established test method for determining the breaking strength and elongation of textile fabrics. The ASTM D5034 and ISO 13934-2 standards describe the procedure for this tensile test, in which a central area of a textile specimen is stretched and loaded up to break. This method is particularly suitable for woven, nonwoven, and felted materials and provides practical characteristic values for evaluating the mechanical strength of textiles.
In contrast to the strip method according to ASTM D5035 and ISO 13934-1, in which the entire textile strip is clamped and uniformly loaded, the grab test focuses on a narrower area in the center of the specimen to examine the bonding behavior within the textile fabric. The method is therefore better suited for a practical assessment of material performance under real-world conditions.
ISO 1421, on the other hand, is specifically aimed at rubber or plastic-coated textiles. The grab test for geotextiles is standardized in ASTM D4632.
Application Differentiation from the other standards Grab test vs. Modified grab Characteristic values Test procedure & Test equipment Request a consultation Downloads
Application area of the grab test according to ASTM D5034 and ISO 13934-2
The grab test according to ASTM D5034 and ISO 13934-2 applies primarily to woven textiles, but can also be applied to other fabrics. It is suitable for quality control in production as well as for incoming goods or comparative testing in the laboratory. Examples of application areas include:
- Technical textiles (e.g. filter media, protective clothing)
- Home textiles (e.g. upholstery fabrics, curtains)
- Medical textiles (e.g. surgical drapes)
- Textiles for the automotive industry (e.g. testing of airbag fabric)
Typically, the grab test according to ASTM D5034 / ISO 13934-2 is not applicable to elastic woven fabrics, geotextiles, glass fiber fabrics, and textile fabrics made of carbon fibers or polyolefin fiber yarns.
Differentiation from other test methods
| Standard | Method | Typical application |
|---|---|---|
| ISO 1421 | Method 1: Strip tensile test Method 2: Grab test | Coated textiles (e.g. with plastic or rubber) |
| ISO 13934-1 ASTM D5035 | Maximum tensile strength and elongation Strip tensile test | Textile fabrics in general |
| ISO 13934-2 ASTM D5034 | Maximum tensile force Grab tensile test | Composite behavior within a tissue |
| ISO 13935-2 | Seam strength (maximum tensile force) Grab tensile test | Faster seam testing with less specimen preparation |
| ASTM D4632 | Maximum tensile strength and elongation Grab tensile test | Specifically for geotextiles |
| ISO 9073-18 | Maximum tensile strength and elongation Grab tensile test | Specifically for nonwovens |
Distinction between the grab test and modified grab test
The grab test methods according to ASTM D5034 (G) and ISO 13934-2 are technically almost identical in their implementation – differences mainly exist in regional distribution (ASTM: USA, ISO: international). The modified grab test (MG) is only defined in ASTM for high-strength, fraying fabrics.
| Criteria | Grab test | Grab test (G) | Modified grab test (MG) |
|---|---|---|---|
| Normative reference | ISO 13934-2 | ASTM D5034 | ASTM D5034 |
| Specimen width | 100 ± 2 mm | 100 ± 1 mm (4 ± 0.05 in) | 100 ± 1 mm (4 ± 0.05 in) |
| Specimen length | Grip-to-grip separation of >100 mm must be ensured | ≥ 150 mm (6 in) with an overhang of at least 10 mm above and below the gripping areas | ≥ 150 mm (for high-strength fabric: ≥ 400 mm) |
| Marking | 38 mm from the side edge | 37 ± 1 mm from the side edge | 37 ± 1 mm from the side edge |
| Side cuts | No | No | Yes, everything except 25 mm in the middle is cut |
| Gripping surfaces | 25 × 25 mm or 25 × 50 mm | 25 × 25 mm or 25 × 50 mm | Min. 25 × 50 mm (top), 50 × 50 mm (bottom) |
| Tensile speed | 50 mm/min | 300 mm/min ± 10 mm/min (12 ± 0.5 in/min) | 300 mm/min ± 10 mm/min (12 ± 0.5 in/min) |
| Application | Fabrics, nonwovens | Fabrics, nonwovens | High-strength or fraying fabric |
| Advantages / Special features | Practical, internationally recognized; support from adjacent threads contributes | Practical, mainly used in the USA; support from adjacent threads contributes | Reduced fraying, targeted stress limited to the central fabric area |
Important characteristic values according to ASTM D5034 and ISO 13934-2
The following characteristic values are determined in the grab test according to ISO 13934-2 and ASTM D5034:
- Breaking force: Maximum force that can be applied before the material fails. It is usually expressed in newtons (N).
- Elongation: Extension of the specimen until break, expressed as a percentage of the original length.
These values provide information about the mechanical strength of a material under realistic conditions.
How is the grab test performed and what test equipment is relevant?
The grab test to ASTM D5034 and ISO 13934-2 can be performed in both normal climate and in wet conditions.
Two textile specimens are always tested: once in the warp direction and once in the weft direction.
- According to ISO 13934-2, each specimen must be (100 ± 2) mm wide and long enough to ensure the grip-to-grip separation of 100 mm in the middle part of the specimen.
- ASTM D5034 specifies a specimen width of 100 ± 1 mm (4 ± 0.05 in) and a specimen length of at least 150 mm (6 in), with a projection of at least 10 mm above and below the specimen grips.
- A marking line of 37 ± 1 mm (ASTM) or 38 mm (ISO) from the edge of the specimen ensures correct positioning in the specimen grip.
The grab test is performed using a tensile testing machine with a constant test speed. ZwickRoell offers a wide selection of universal testing machines, such as the ZwickRoell zwickiLine single-column testing machine for low forces up to 5 kN, or our ProLine and AllroundLine series , depending on the required force range and desired level of automation.
Only the middle section of the specimen is secured in the specimen grip. As a result, adjacent threads also contribute to the test, which more closely approximates the actual behavior of the material. Due to the surface properties of the most commonly used fabrics, single-sided pneumatic grips with high clamping force are preferred to prevent slippage or damage during clamping.
The universal testing machine pulls the specimen apart at a constant test speed of 300 mm/min ± 10 mm/min (12 ± 0.5 in/min) according to ASTM or 50 mm/min (ISO) until it breaks.
Force and elongation are measured along the crosshead travel. For greater measurement accuracy, a video extensometer can be optionally integrated for precise elongation measurement.
The testXpert testing software automatically calculates breaking force, elongation, and other relevant parameters – in compliance with standards and fully documented.
ZwickRoell also offers automated solutions for textile testing with specimen feeding and intelligent specimen management for high test rates or use in quality assurance.
Would you like to perform the grab test according to ISO 13934-2 or ASTM D5034?
Our industry expert for textile applications will assist you in selecting the right testing machine and in implementing your testing tasks in accordance with the relevant standards. Benefit from our many years of expertise in textile testing technology.
Downloads
- Product information: zwickiLine Up to Fmax 5 kN PDF 820 KB
- Product Information: ProLine, Fmax 5-100 kN PDF 1 MB
- Product Information: AllroundLine, Fmax 5-100 kN PDF 1 MB
- Product Information: Pneumatic grips, Fmax 5 kN/10 kN/30 kN PDF 387 KB
- Product Information: videoXtens 1-120 P / HP PDF 1 MB
- Product Information: Robotic Testing System roboTest F (Non-Rigid) PDF 98 KB
- Industry Brochure: Textiles PDF 4 MB
