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CAN CGSB 4.2 No. 15-2003 (2013) – Breaking Strength of Yarns (Single Strand Method): Testing Requirements and Compliance
A comprehensive guide to the Canadian standard for determining the breaking force and elongation of single yarn strands using constant rate of extension (CRE) testing machines
1. Scope and Application
CAN CGSB 4.2 No. 15-2003 (2013), titled Textile Test Methods – Breaking Strength of Yarns – Single Strand Method, is a Canadian national standard issued by the Canadian General Standards Board (CGSB). It establishes a uniform procedure for determining the maximum breaking force (tensile strength) and the corresponding elongation at the moment of rupture of yarns taken from packages. The test is performed on a single strand of yarn using a constant rate of extension (CRE) testing machine.
The standard applies to most types of yarn—including spun yarns, continuous filament yarns, and textured yarns—provided they can be wound into packages and do not exceed the capacity of the testing equipment. It is widely used in the textile industry for quality control, product specification, and acceptance testing of yarns intended for woven or knitted fabrics.
Tip: For yarns that are too short or cannot be tested in a single strand (e.g., from fabric ravel), alternative methods such as the skein test (CAN CGSB 4.2 No. 14) may be more appropriate.
2. Technical Requirements and Test Methodology
2.1 Principle
A length of yarn is clamped at both ends and stretched at a constant rate of extension until it breaks. The breaking force and elongation are recorded. The test is performed on a conditioned specimen in a standard atmosphere.
2.2 Apparatus
- Constant rate of extension (CRE) testing machine – capable of measuring force with an accuracy of ±1% of full scale or better, with a constant speed of the moving clamp.
- Clamps – designed to avoid slippage or damage; typically manual or pneumatic flat-faced clamps lined with rubber or similar material.
- Conditioning chamber – maintaining the standard atmosphere of 20 ± 2 °C and 65 ± 4 % relative humidity.
2.3 Specimen Preparation
- Yarn is taken from the package without tension or disturbance of twist.
- Specimens must be conditioned for at least 4 hours in the standard atmosphere.
- The nominal gauge length is 250 mm for yarns with an elongation at break up to 20%, and 500 mm for yarns with higher elongation (e.g., elastomeric yarns).
- At least 10 tests are performed per package, with more required for statistical confidence.
2.4 Test Parameters
The following table summarizes the key test parameters specified in CAN CGSB 4.2 No. 15-2003 (2013).
| Parameter | Specification | Remarks |
|---|---|---|
| Gauge length | 250 mm or 500 mm | Use 500 mm for yarns with elongation > 20% |
| Rate of extension | 300 mm/min for 250 mm gauge length; 500 mm/min for 500 mm gauge length | Constant rate of extension (CRE) |
| Pre-tension | 0.5 ± 0.1 cN/tex (or as specified in the yarn standard) | Applies a small initial load to align the strand |
| Number of tests per package | At least 10 | Increase for high variability |
| Conditioning atmosphere | 20 ± 2 °C, 65 ± 4 % RH | Test in the same atmosphere, or within 5 minutes of removal |
| Application of pretension | 5 seconds before starting the test | Ensures the strand is straight |
2.5 Calculations
- Breaking force – the maximum force recorded, expressed in newton (N) or centinewton (cN).
- Breaking tenacity – breaking force per unit linear density (cN/tex or N/tex).
- Elongation at break – the increase in length at the moment of rupture, expressed as a percentage of the initial gauge length.
- All values are averaged and reported with appropriate statistical measures (mean, standard deviation).
Important: When testing yarns with high or low elongation, confirm that the chosen gauge length and extension rate comply with the standard. Using the incorrect gauge length can significantly affect the elongation results.
3. Implementation Highlights
3.1 Conditioning and Handling
Proper conditioning is critical. The standard requires that yarn specimens be exposed to the standard atmosphere for at least 4 hours prior to testing. The test itself should be conducted in the same atmosphere, or if this is not possible, each specimen must be tested within 5 minutes of removal from the conditioning environment. Hands and handling should be minimized to avoid transferring moisture or disturbing the yarn twist.
3.2 Mounting and Alignment
The yarn strand must be mounted without tension (except the specified pretension) and must be perpendicular to the clamp faces. Any off-axis mounting can cause complex stresses and reduce the measured breaking force. Pneumatic clamps are preferred for their reproducibility and reduced operator influence.
3.3 Equipment Calibration
The CRE machine must be calibrated regularly according to the manufacturer’s instructions and a recognized traceable standard (e.g., using certified weights). The extension measurement should also be verified (e.g., via a calibrated ruler or calibration certificate).
3.4 Relation to International Standards
CAN CGSB 4.2 No. 15-2003 (2013) is technically equivalent to ISO 2062:2009 (Textiles – Yarns from packages – Determination of single-end breaking force and elongation at break using constant rate of extension (CRE) testing machines). Laboratories that already operate to ISO 2062 will find the test procedure essentially identical. However, for compliance with Canadian regulations, the CGSB version is required when referencing Canadian standards.
Success: Compliance with CAN CGSB 4.2 No. 15-2003 (2013) is often requested by Canadian textile manufacturers and government procurement agencies. Using the standard ensures that yarn quality meets domestic performance expectations.
4. Compliance and Quality Assurance Notes
4.1 Statistical Quality Control
The standard recommends a minimum of 10 tests per package. For quality control charts, laboratories often test 20 or more specimens to achieve tighter control limits. Outliers must be investigated using statistical criteria such as the Grubbs test or IQR method, and any broken results due to slipping or jaw holding errors should be discarded.
4.2 Precision and Bias
The precision statement in the standard provides within-laboratory and between-laboratory variation data derived from inter-laboratory trials. For example, for a typical cotton yarn with a mean breaking force of 300 cN, the repeatability limit (within laboratory) is about 3% of the mean, and the reproducibility limit (between laboratories) is about 6%. Laboratories should use these values to assess the reliability of their results.
4.3 Reaffirmation Status
The standard was reaffirmed in 2013 (as indicated by the date 2013 in the title). This means that the technical content of the 2003 edition was reviewed and confirmed as still current. As of 2026, this standard remains the accepted CGSB method for single strand yarn breaking strength testing, though users are advised to check the CGSB website for any updates or proposed revisions.
4.4 Recording and Reporting
The test report must include the following information: complete reference to this standard (CAN CGSB 4.2 No. 15-2003 (2013)), the yarn identification, conditioning atmosphere, gauge length, extension rate, number of tests, individual and average breaking force, tenacity (if required), and elongation. Any deviations from the standard method must be noted.
Caution: If yarn breaks at the clamp edge (jaw break) more than 10% of the time, the test may be invalid. In such cases, consider using padding or adjusting the clamping pressure. Do not accept results where the break occurs within 5 mm of the clamp without a clear cause.
Frequently Asked Questions
Q: What gauge length is required for CAN CGSB 4.2 No. 15-2003 (2013)?
A: The standard specifies a nominal gauge length of 250 mm for yarns with an elongation at break up to 20 % and 500 mm for yarns with higher elongation (e.g., stretc, elastomeric yarns). Always refer to the individual yarn specification or product standard for any special requirements.
A: The standard specifies a nominal gauge length of 250 mm for yarns with an elongation at break up to 20 % and 500 mm for yarns with higher elongation (e.g., stretc, elastomeric yarns). Always refer to the individual yarn specification or product standard for any special requirements.
Q: How does this method differ from fabric tensile tests like CAN CGSB 4.2 No. 2?
A: Fabric tensile tests (e.g., strip or grab tests) measure the breaking strength of a fabric, which includes the contribution of weave, knit, and finishing. The single strand method evaluates the yarn alone, eliminating the fabric construction effects. This distinction is crucial for yarn quality control or when a problem is suspected in the yarn itself.
A: Fabric tensile tests (e.g., strip or grab tests) measure the breaking strength of a fabric, which includes the contribution of weave, knit, and finishing. The single strand method evaluates the yarn alone, eliminating the fabric construction effects. This distinction is crucial for yarn quality control or when a problem is suspected in the yarn itself.
Q: Is CAN CGSB 4.2 No. 15-2003 (2013) equivalent to ISO 2062?
A: Yes, for most practical purposes the two standards are technically equivalent. The test parameters (gauge length, extension rate, pretension, number of tests) are the same. However, the CGSB standard may include additional notes specific to Canadian industry practice. For Canadian regulatory acceptance, the CGSB designation is required.
A: Yes, for most practical purposes the two standards are technically equivalent. The test parameters (gauge length, extension rate, pretension, number of tests) are the same. However, the CGSB standard may include additional notes specific to Canadian industry practice. For Canadian regulatory acceptance, the CGSB designation is required.
Q: What is the typical time to complete a full test series?
A: With a modern CRE tester and pneumatic clamps, a single test takes about 30–60 seconds, including mounting and breaking. A series of 10 tests per package can be completed in approximately 10–15 minutes, excluding conditioning time (at least 4 hours). This makes the method suitable for routine quality control in production environments.
A: With a modern CRE tester and pneumatic clamps, a single test takes about 30–60 seconds, including mounting and breaking. A series of 10 tests per package can be completed in approximately 10–15 minutes, excluding conditioning time (at least 4 hours). This makes the method suitable for routine quality control in production environments.
This article is current as of 2026. Always verify the latest version of the standard with CGSB or authorized distributors.