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CAN CGSB 4.159-75 (2013) — Standard Test Method for Resistance to Slippage of Yarns in Woven Fabrics
A Comprehensive Guide to Seam Slippage Testing for Canadian Textile Quality Assurance
CAN CGSB 4.159-75 (2013), titled “Resistance to Slippage of Yarns in Woven Fabrics”, is a Canadian national standard developed by the Canadian General Standards Board (CGSB). Originally published in 1975 and reaffirmed in 2013, this standard provides a uniform test method for measuring the resistance to yarn slippage at seams in woven textiles. It is widely referenced in quality assurance protocols for apparel, upholstery, industrial fabrics, and military specifications that require consistent seam performance.
Scope and Purpose
The standard defines a procedure for determining the force required to cause a specified amount of yarn slippage (typically 3 mm or 6 mm) when a seam is subjected to a transverse tensile force. It applies to most woven fabrics made from natural, synthetic, or blended fibres. The test is designed to simulate the stresses that seams experience during use, such as those at the shoulders, seat, or armhole of a garment, or in industrial fabric constructions.
Important: This standard is not intended for non‑woven fabrics, knitted structures, or fabrics incorporating elastomeric yarns (e.g., spandex) without prior validation. Coated or heavily treated fabrics may require modified specimen preparation to avoid unrealistic results.
The primary purpose of the test is to assess the likelihood of seam slippage, which can lead to seam failure or an unacceptable change in fabric appearance. By establishing a standardized measurement, CAN CGSB 4.159-75 (2013) enables manufacturers, specifiers, and regulatory bodies to compare the performance of different fabric constructions under consistent conditions.
Technical Requirements and Test Procedure
Test Apparatus
The test is performed using a constant‑rate‑of‑extension (CRE) tensile testing machine capable of recording force to an accuracy of ±1 % of the indicated value. Key components include:
- Jaws – Two sets of flat, serrated or rubber‑faced clamps that grip the specimen across its full width without slippage.
- Template – A cutting template to ensure reproducible specimen dimensions (typically 100 mm × 350 mm for the seam slip assembly).
- Seaming equipment – A sewing machine capable of producing a consistent seam using the stitch type and thread specified in the standard.
- Conditioning chamber – For bringing specimens to moisture equilibrium at 20 ± 2 °C and 65 ± 4 % relative humidity.
| Parameter | Requirement |
|---|---|
| Nominal gauge length | 75 mm (distance between jaws) |
| Rate of extension | 300 mm/min (constant) |
| Specimen width | 100 mm (cut); 50 mm effective test width after folding |
| Seam type | Single‐lockstitch (ISO 4915 class 301) or double‐lockstitch (class 401) |
| Stitch density | 4 ± 0.5 stitches per centimeter |
| Seam allowance | 12 mm |
| Number of specimens | 5 warp (lengthwise) and 5 weft (crosswise) specimens |
| Conditioning time | Minimum 24 hours at standard atmosphere |
Tip: Always condition specimens for at least 24 hours at 20 °C and 65 % RH before testing. Rapid changes in ambient conditions can affect yarn recovery and lead to inconsistent slippage readings.
Specimen Preparation
From each fabric sample, five warp‑direction and five weft‑direction specimens are cut. Each specimen is folded in half, and a seam is sewn parallel to the fold at the specified allowance using the required stitch type and density. The seam construction must be representative of the intended end use or as agreed between parties. The sewn specimen is then trimmed to a final width of 100 mm, with the seam centered. Care must be taken to avoid distortion or stretching during cutting and sewing.
Common mistake: Using a seam allowance different from 12 mm, or a stitch density outside the specified tolerance, can shift the slippage force by more than 15 %, especially in tightly woven fabrics. Always verify seam parameters before testing.
Test Procedure
- Mount the prepared specimen in the CRE machine with the seam positioned centrally between the jaws. The seam line should be exactly perpendicular to the direction of pull.
- Apply a pre‑tension of 2 N to remove any slack (or as specified in the standard’s procedure).
- Commence the extension at 300 mm/min and record the force–extension curve.
- Note the force at which a yarn slippage of 3 mm and/or 6 mm occurs. Slippage is defined as the visible displacement of warp or weft yarns relative to the seam line.
- Continue until specimen rupture or until a predetermined extension limit is reached.
- Repeat for the remaining nine specimens.
Calculation and Reporting
For each set of five specimens (warp and weft separately), calculate the arithmetic mean slippage force at the required displacement. Also report the standard deviation and coefficient of variation. The report must include:
- Fabric identification (construction, fibre content, mass per unit area);
- Seam and stitch details;
- Conditioning parameters;
- Individual and mean slippage forces (in newtons) with the corresponding displacement;
- Mode of failure (yarn slippage, yarn rupture, seam rupture, etc.).
Implementation Highlights
CAN CGSB 4.159-75 (2013) is a cornerstone test for textile quality control in Canada. It is routinely used by:
- Apparel manufacturers – To evaluate seam integrity in shirts, trousers, and outerwear.
- Industrial textile producers – For conveyor belts, tents, and geotextiles where seam loading is critical.
- Government procurement agencies – As part of specifications for uniform fabrics and other defense‑related textiles.
- Third‑party testing laboratories – To certify that products meet Canadian regulatory or customer requirements.
Compliance advantage: Conformance with CAN CGSB 4.159-75 (2013) demonstrates due diligence in quality assurance and facilitates acceptance by major Canadian retailers and specifiers.
The 2013 reaffirmation by the CGSB Technical Committee confirmed that the test method remains technically valid and aligned with current industry practices. While no changes were made to the technical content, the reaffirmation certifies that the standard has been reviewed and is still suitable for its intended purpose. Users should confirm the exact reaffirmation date and any editorial modifications in the latest edition published by the CGSB.
Compliance and Reaffirmation Notes
CAN CGSB 4.159-75 (2013) is harmonized in principle with ASTM D434 “Standard Test Method for Resistance to Slippage of Yarns in Woven Fabrics (Using a Seam)” and ISO 13936‑1 “Textiles — Determination of the slippage resistance of yarns at a seam in woven fabrics — Part 1: Fixed seam opening method.” However, differences in specimen dimensions, gauge length, and interpretation criteria exist. Laboratories that are accredited to multiple standards must verify that the specific requirements of CAN CGSB 4.159-75 (2013) are met when declaring compliance to that standard.
Tip: When converting test results between CAN CGSB 4.159‑75 (2013) and ASTM D434, or between ISO 13936‑1, always compare the failure criteria and seam construction parameters. Correlation factors should be established using a representative set of fabrics rather than relying on general rules.
Key compliance considerations include:
- Calibration of the tensile testing machine must be traceable to national standards and performed at least annually.
- Seam sewing must be performed using a machine capable of maintaining the specified stitch density within tolerance.
- Test results are only valid for the fabric orientation tested; both warp and weft directions must be reported separately.
- The standard does not define acceptance levels; pass/fail criteria must be agreed upon between the supplier and the purchaser or be based on product specifications.
Caution: Using a gauge length or extension rate different from those specified in the standard will invalidate the test. Always verify the settings on the CRE machine before each test session.
Given its age, some users question whether CAN CGSB 4.159-75 (2013) remains current. The 2013 reaffirmation confirms that the Technical Committee found no technical obsolescence. Nevertheless, for modern fabrics with finishes or construction types not available in 1975, supplementary testing or method modifications should be documented and agreed upon in advance.
Frequently Asked Questions
Q: What is the difference between CAN CGSB 4.159‑75 (2013) and ASTM D434?
A: Both standards measure yarn slippage resistance at a seam, but they differ in specimen size (100 mm vs. 150 mm), gauge length (75 mm vs. 25 mm), and rate of extension (300 mm/min vs. 50 mm/min). The seam construction and the definition of “slippage” also have subtle variations. Therefore, direct conversion of results without correlation is not recommended.
A: Both standards measure yarn slippage resistance at a seam, but they differ in specimen size (100 mm vs. 150 mm), gauge length (75 mm vs. 25 mm), and rate of extension (300 mm/min vs. 50 mm/min). The seam construction and the definition of “slippage” also have subtle variations. Therefore, direct conversion of results without correlation is not recommended.
Q: Is this standard applicable to all woven fabrics?
A: It is applicable to the majority of conventional woven fabrics. However, fabrics with a high degree of stretch (due to elastomeric yarns), those with lubricant finishes, or heavily coated fabrics may not produce repeatable results without modifications. In such cases, an alternative method such as the grip‑slippage test (e.g., ASTM D4034) might be more appropriate.
A: It is applicable to the majority of conventional woven fabrics. However, fabrics with a high degree of stretch (due to elastomeric yarns), those with lubricant finishes, or heavily coated fabrics may not produce repeatable results without modifications. In such cases, an alternative method such as the grip‑slippage test (e.g., ASTM D4034) might be more appropriate.
Q: What does the “2013 reaffirmation” mean practically?
A: A reaffirmation means the standard was reviewed by the CGSB Technical Committee and found to still meet the needs of the industry. No technical changes were made; the 2013 edition is identical in content to the 1975 edition. The reaffirmation symbol (2013) indicates that the standard is current and should be referenced as CAN CGSB 4.159‑75 (2013).
A: A reaffirmation means the standard was reviewed by the CGSB Technical Committee and found to still meet the needs of the industry. No technical changes were made; the 2013 edition is identical in content to the 1975 edition. The reaffirmation symbol (2013) indicates that the standard is current and should be referenced as CAN CGSB 4.159‑75 (2013).
Q: How many specimens are required, and how are results interpreted?
A: The standard requires five specimens in the warp direction and five in the weft direction, each tested individually. The mean slippage force (e.g., at 3 mm or 6 mm displacement) is reported for each orientation. The standard does not provide acceptance limits; these are set by the customer or product specification.
A: The standard requires five specimens in the warp direction and five in the weft direction, each tested individually. The mean slippage force (e.g., at 3 mm or 6 mm displacement) is reported for each orientation. The standard does not provide acceptance limits; these are set by the customer or product specification.
Article last reviewed: 2026. The information provided is for general informational purposes and should be confirmed with the official standard document published by the Canadian General Standards Board.