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CAN CGSB 4.2 No. 11.1-94 (2013): Standard Test Method for Breaking Strength of Textile Fabrics – Grab Method
A Comprehensive Overview of the Canadian Standard for Determining Breaking Strength in Woven and Nonwoven Textiles
Scope and Applicability
CAN CGSB 4.2 No. 11.1-94 (2013) — Textile Test Methods: Breaking Strength of Textile Fabrics — Grab Method — is a longstanding Canadian General Standards Board (CGSB) standard that specifies a procedure for determining the breaking strength and elongation of woven and nonwoven textile fabrics. The method is applicable to most textile fabrics, including those that are highly extensible or exhibit a pronounced slip or crimp interchange. It is widely used in quality control, material specification, and product development to ensure fabric performance meets end-use requirements.
The grab method differs from the strip method by clamping the specimen across its entire width in the centre only, allowing the fabric to contract laterally during the test. This approach better simulates the stress conditions experienced by fabrics in many practical applications, such as seams or points of concentrated loads.
Tip: Although the standard was originally published in 1994, the 2013 reaffirmation confirms its continued relevance and alignment with modern industry practices. Always refer to the latest reaffirmation for any amendments or editorial corrections.
Technical Requirements
Specimen Preparation
Each specimen shall be cut to a width of 100 ± 1 mm and a length of at least 200 mm, with the longer dimension parallel to the direction of testing (warp or weft). The central portion is reduced to a width of 75 ± 1 mm by carefully raveling the same number of yarns from each side. The specimen ends must be cleanly cut and free of flaws. A minimum of five specimens per direction is required; additional specimens may be needed for fabrics exhibiting high variability.
Conditioning and Atmosphere
Prior to testing, specimens must be conditioned in a standard atmosphere of 21 ± 1 °C and 65 ± 2% relative humidity for at least 24 hours. The standard mandates that the entire testing process be conducted under the same controlled conditions to minimize moisture-induced dimensional changes and strength variation.
Testing Apparatus
A constant-rate-of-extension (CRE) tensile testing machine equipped with flat-faced, smooth-jawed clamps is required. The jaw faces must be at least 25 mm wide and 50 mm long to securely grip the raveled portion of the specimen. A gauge length of 75 ± 1 mm is specified, and the rate of traverse shall be 300 ± 10 mm/min. The force-measuring system must be capable of recording peak load with an accuracy of ± 1% of the indicated value.
Procedure
The specimen is centered and clamped in the jaws with the raveled width lying between the jaw faces. The machine is started, and the specimen is pulled to rupture. The maximum force (in newtons) and elongation at break (in millimetres) are recorded. If a specimen slips in the jaws, breaks at the jaw edge, or exhibits abnormal yarn breakage, the result is discarded and a replacement specimen is tested.
Warning: For anisotropic fabrics (e.g., those with different strengths in warp and weft), test both directions separately. Do not average results across different directions, as this may obscure directional performance deficiencies.
Key Parameters Summary
| Parameter | Requirement |
|---|---|
| Specimen original width | 100 ± 1 mm |
| Raveled width (gripped) | 75 ± 1 mm |
| Specimen length | ≥ 200 mm |
| Gauge length | 75 ± 1 mm |
| Rate of extension | 300 ± 10 mm/min |
| Number of specimens per direction | 5 (minimum) |
| Conditioning atmosphere | 21 ± 1 °C, 65 ± 2% RH |
| Force measurement accuracy | ± 1% of indicated value |
Implementation Highlights
When integrating CAN CGSB 4.2 No. 11.1-94 (2013) into a laboratory quality management system, several practical aspects merit attention:
- Operator training: Consistent raveling technique and proper specimen alignment are essential for repeatable results. Operators should undergo periodic competency assessments.
- Machine verification: Regular calibration of the load cell and verification of jaw speed (using a suitable tachometer or ruler) should be performed according to ISO 7500-1 or equivalent guidelines.
- Data interpretation: Report both the mean and coefficient of variation for each test direction. For materials that exhibit a yield point prior to rupture, note this characteristic in the test report.
- Moisture sensitivity: Certain fibres (e.g., cotton, rayon) are highly hygroscopic. Even short exposure to ambient conditions after conditioning can alter strength; therefore, test specimens as rapidly as possible.
Best Practice: For fabrics that tend to slip or break at the jaw face, consider using jaw-face liners (e.g., rubber or grit-embedded) or increasing the clamping pressure, provided these modifications are noted in the test report.
Compliance and Reaffirmation Notes
CAN CGSB 4.2 No. 11.1-94 was reaffirmed in 2013 without technical changes, indicating that the method remains valid and widely accepted. Users should be aware that the standard includes an appendix with guidance on alternative jaw-face configurations and on testing fabrics that are too narrow for standard specimen dimensions.
Compliance with this standard is a common requirement for textile products procured by Canadian government agencies and is frequently referenced in procurement specifications for uniforms, protective clothing, and industrial textiles. Laboratories seeking accreditation for textile testing should include this method in their scope of accreditation under ISO/IEC 17025.
Important: This standard does not address all safety concerns, if any, associated with its use. It is the responsibility of the user to establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to use.
Frequently Asked Questions
Q: What is the difference between the grab method and the strip method for breaking strength?
A: In the strip method, the entire specimen width (e.g., 50 mm) is clamped, preventing lateral contraction. The grab method clamps only a central 75 mm portion, allowing the fabric to contract and better simulate real-world stress distributions, especially for woven fabrics with high crimp interchange.
A: In the strip method, the entire specimen width (e.g., 50 mm) is clamped, preventing lateral contraction. The grab method clamps only a central 75 mm portion, allowing the fabric to contract and better simulate real-world stress distributions, especially for woven fabrics with high crimp interchange.
Q: Is this standard equivalent to ASTM D5034?
A: While closely aligned in principle, CAN CGSB 4.2 No. 11.1-94 (2013) contains specific Canadian requirements for conditioning atmosphere (21 °C / 65% RH) and specimen dimensions. Users should compare the full documents if equivalency is required for cross-border specifications.
A: While closely aligned in principle, CAN CGSB 4.2 No. 11.1-94 (2013) contains specific Canadian requirements for conditioning atmosphere (21 °C / 65% RH) and specimen dimensions. Users should compare the full documents if equivalency is required for cross-border specifications.
Q: How do I handle fabrics that cannot be raveled (e.g., nonwovens, coated fabrics)?
A: For such materials, the standard permits testing the as-cut width of 100 mm without raveling, provided this deviation is reported. Some nonwovens may require increased specimen width to ensure adequate grip.
A: For such materials, the standard permits testing the as-cut width of 100 mm without raveling, provided this deviation is reported. Some nonwovens may require increased specimen width to ensure adequate grip.
Last updated: 2026