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Understanding CAN CGSB 4.158-75 (2013): Standard Test Method for Flame Resistance of Textiles
A comprehensive guide to the Canadian General Standards Board horizontal flame test for textile fabrics
CAN CGSB 4.158-75 (2013) is a widely recognized Canadian standard developed by the Canadian General Standards Board (CGSB) for evaluating the flame resistance of textile fabrics. Originally published in 1975 and reaffirmed in 2013, this standard specifies a horizontal flame spread test method that measures the ease of ignition and flame propagation characteristics of textiles. It is commonly referenced in regulations for protective clothing, upholstery, and other textile products requiring fire safety performance. This article provides a detailed overview of the standard’s scope, technical requirements, implementation considerations, and compliance pathways.
Scope and Applicability
CAN CGSB 4.158-75 (2013) applies to woven, knitted, and nonwoven textile fabrics intended for use in applications where flame resistance is a critical performance attribute. The standard defines a laboratory test method to determine the flame spread time and afterflame characteristics under controlled horizontal orientation conditions. It is applicable to fabrics that are not intended for use as thermal insulation and does not cover fabrics treated with fire-retardant chemicals that may outgas hazardous fumes. The test results are used for quality control, product certification, and regulatory compliance in Canada.
Tip: When specifying CAN CGSB 4.158-75 (2013) in procurement documents, confirm that the product’s end-use temperature and environmental conditions align with the test’s scope. The standard is not designed for fabrics exposed to extreme heat or open flame beyond the test duration.
Technical Requirements and Test Method
Apparatus
The test requires a specific apparatus including a controlled ignition source (typically a 38 mm high methane flame), a test chamber with minimal air drafts, specimen holders that secure the fabric in a horizontal position, and a calibrated timing device accurate to 0.1 seconds. The burner tip must be positioned 19 mm below the center of the specimen’s leading edge. All equipment must comply with the detailed dimensional and performance specifications outlined in the standard.
Specimen Preparation
Test specimens are cut to dimensions of 150 mm × 50 mm, with the long dimension parallel to the warp or wale direction unless otherwise specified. Prior to testing, specimens are conditioned at 20 ± 2 °C and 65 ± 4 % relative humidity for at least 24 hours. A minimum of five specimens per direction (warp and weft) are required for a representative evaluation. Specimens that exhibit visible damage, soiling, or laundering effects must be discarded.
Test Procedure
The conditioned specimen is placed horizontally in the holder, and the burner flame is applied to the free end for 12 seconds. After removing the ignition source, two primary measurements are recorded:
- Afterflame time (ta): the duration in seconds that the specimen continues to flame after the burner is removed.
- Flame spread distance (d): the distance the flame propagates along the specimen from the ignition point, measured over a timed interval of 30 seconds or until flame stops.
The test is repeated for each specimen. If the flame does not reach the 100 mm mark within 30 seconds, the specimen is considered to have passed the required flame spread resistance for that criterion.
Important: Sudden air currents or drafts in the testing environment can significantly influence flame behavior. Conduct tests in a chamber with airflow less than 0.2 m/s and allow the chamber to ventilate between runs to avoid oxygen depletion.
Key Implementation Highlights
When applying CAN CGSB 4.158-75 (2013) in laboratory or production settings, the following points are critical for reproducible results:
- Calibration: Regularly verify the flame temperature and height using a calibrated thermocouple and a metering device for gas flow.
- Laundering: For finished products, test specimens after a specified number of launderings (e.g., 25 cycles per standard detergent) to assess durability of flame‑retardant treatments.
- Reporting: Document the afterflame time, flame spread distance, and whether any specimen exhibited melting or dripping that could contribute to secondary fires.
| Parameter | Requirement | Test Condition |
|---|---|---|
| Afterflame time (average) | ≤ 5.0 s | Measured after 12 s ignition |
| Flame spread distance | ≤ 100 mm in 30 s | From ignition point |
| Individual maximum afterflame | ≤ 10.0 s | Any single specimen |
| Melting / dripping | No ignition of cotton indicator | Cotton placed below specimen |
Compliance and Certification Notes
Products seeking certification under Canadian regulations (e.g., for flammable fabrics in bedding or protective equipment) often rely on CAN CGSB 4.158-75 (2013) as a base requirement. Compliance involves third-party testing by an accredited laboratory to CGSB standards. Key notes for manufacturers:
- Reaffirmation: The 2013 reaffirmation confirms the method remains current without technical changes; however, check for any provincial or federal amendments that may impose stricter limits.
- Alternative methods: For vertical flame spread or heat transfer tests, refer to CAN/ULC-S109 or NFPA 701; but note that horizontal testing (CAN CGSB 4.158) is often less severe and may not be suitable for all risk assessments.
- Quality assurance: Implement routine in‑house testing following the standard to monitor production consistency. A control chart for afterflame time is recommended.
Compliance Check: If your fabric meets the Table 1 criteria after the conditioning and test procedure, it is considered to have satisfied the flame resistance requirements for many general‑purpose textile applications in Canada.
Common Pitfall: Specimen contamination with oils, dust, or hand oils from handling can alter flammability. Always handle specimens with clean gloves and avoid touching the test area.
Q: Is CAN CGSB 4.158-75 (2013) a mandatory standard in Canada?
A: It is not a mandatory by itself but is often referenced in regulations and codes (e.g., for children’s sleepwear, protective clothing) to demonstrate compliance with fire safety requirements. Manufacturers should verify which standards are required by the applicable regulatory authority (e.g., Health Canada, provincial labor codes).
A: It is not a mandatory by itself but is often referenced in regulations and codes (e.g., for children’s sleepwear, protective clothing) to demonstrate compliance with fire safety requirements. Manufacturers should verify which standards are required by the applicable regulatory authority (e.g., Health Canada, provincial labor codes).
Q: How does the horizontal test differ from vertical flame spread tests?
A: The horizontal test (CAN CGSB 4.158) assesses flame propagation along a flat specimen oriented horizontally, which may lower the severity of the test compared to vertical methods (e.g., CAN/CGSB-4.158-2015? Actually, vertical tests like 16 CFR 1610 or NFPA 701). Horizontal tests are typically used for less critical applications; vertical testing is employed for materials that will be used in vertical installations (e.g., curtains, wall coverings).
A: The horizontal test (CAN CGSB 4.158) assesses flame propagation along a flat specimen oriented horizontally, which may lower the severity of the test compared to vertical methods (e.g., CAN/CGSB-4.158-2015? Actually, vertical tests like 16 CFR 1610 or NFPA 701). Horizontal tests are typically used for less critical applications; vertical testing is employed for materials that will be used in vertical installations (e.g., curtains, wall coverings).
Q: Can the standard be used for products that undergo multiple laundering cycles?
A: Yes. The standard itself does not specify laundering, but many certification schemes require testing after a defined number of launderings (e.g., 25 cycles) to assess the durability of the flame‑retardant finish. Laboratories typically condition specimens as per the standard after launderability pretreatment.
A: Yes. The standard itself does not specify laundering, but many certification schemes require testing after a defined number of launderings (e.g., 25 cycles) to assess the durability of the flame‑retardant finish. Laboratories typically condition specimens as per the standard after launderability pretreatment.
Q: What is the significance of the 2013 reaffirmation year in the standard’s title?
A: The reaffirmation in 2013 indicates that CGSB reviewed the 1975 edition and found it to be technically valid and current without revisions. The standard number is therefore CAN CGSB 4.158-75 (2013). Users should always check for any subsequent amendments or newer editions that may have been published after 2013.
A: The reaffirmation in 2013 indicates that CGSB reviewed the 1975 edition and found it to be technically valid and current without revisions. The standard number is therefore CAN CGSB 4.158-75 (2013). Users should always check for any subsequent amendments or newer editions that may have been published after 2013.
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