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CAN CGSB 4.2 No. 49-99 (2013): Standard Test Method for Colourfastness to Light of Textiles Using Xenon Arc Lamp
A comprehensive technical overview of the Canadian standard for evaluating textile colourfastness under controlled artificial light exposure
CAN CGSB 4.2 No. 49-99 (2013) is a Canadian national standard developed by the Canadian General Standards Board (CGSB) that specifies a test method for determining the colourfastness of textile materials to the action of artificial light. This standard is part of the CGSB 4.2 series of textile test methods and is technically equivalent to ISO 105-B02, with modifications to reflect Canadian practice and environmental conditions. It provides a reliable and reproducible procedure for assessing how textile colours resist fading when exposed to a xenon arc light source that simulates natural daylight. The standard applies to textiles of all kinds, including fibres, yarns, fabrics, and finished articles, and is widely used by manufacturers, testing laboratories, and regulatory bodies in Canada and internationally.
Scope of CAN CGSB 4.2 No. 49-99 (2013)
The standard outlines a test method that exposes textile specimens to artificial light from a xenon arc lamp under controlled temperature, humidity, and irradiance conditions. The primary objective is to evaluate the colourfastness of the material by comparing the change in colour of the exposed specimen to that of a set of blue wool reference standards (grades 1 to 8) exposed simultaneously. The method is intended for textiles that will be used in conditions where exposure to light (including daylight and artificial sources) may cause colour fading or change.
Tip: CAN CGSB 4.2 No. 49-99 (2013) is part of a comprehensive suite of textile test methods within the CGSB 4.2 series. Users should also refer to CGSB 4.2 No. 48 for guidance on blue wool standards and colourfastness rating scales.
Technical Requirements and Test Procedure
Test Apparatus: Xenon Arc Lamp
The core equipment required is a xenon arc lamp test chamber capable of providing a spectral distribution of irradiance close to that of natural daylight (including UV components). The apparatus must maintain controlled environmental conditions throughout the exposure cycle, including black standard temperature (BPT or BST), relative humidity, and chamber temperature. The standard specifies two primary exposure conditions: the standard dry bulb temperature of 40 °C ± 1 °C and a wet bulb temperature corresponding to a relative humidity of 40 % ± 3 % for the normal test; a higher humidity condition (60 % ± 3 %) may also be specified for end-use environments.
| Parameter | Condition A (Standard) | Condition B (High Humidity) |
|---|---|---|
| Black Standard Temperature | 47 °C ± 1 °C | 47 °C ± 1 °C |
| Relative Humidity | 40 % ± 3 % | 60 % ± 3 % |
| Chamber Temperature (dry bulb) | 40 °C ± 1 °C | 40 °C ± 1 °C |
| Irradiance (at specimen plane) | 1.10 W/(m²·nm) at 420 nm | 1.10 W/(m²·nm) at 420 nm |
| Exposure duration | 20 to 100 h (depending on grade) | As agreed |
Test Specimens and Exposure Cycle
Test specimens are prepared by mounting the textile material on opaque non-fluorescent backing cards. At least two specimens per sample are typically tested. The blue wool reference standards (grades 1 to 8) are mounted in a similar manner and placed alongside the specimens in the exposure unit. The exposure is continued until the contrast between the exposed and unexposed portions of the first blue wool reference (grade 1) reaches a specified colour difference (grey scale rating 3–4). The exposure is considered complete when a defined change in the specimen or the reference is achieved, typically after a prescribed number of hours or after the specimen reaches a predetermined fading endpoint.
Important: The standard requires that the xenon arc lamp be filtered to provide a spectral distribution meeting the requirements of CGSB 4.2 No. 49. Regular calibration of the irradiance and temperature sensors is essential for reproducible results. Use a reference material check to verify the performance of the apparatus.
Implementation Highlights
Sample Preparation and Mounting
Specimens must be representative of the textile material being tested. For yarns, they may be wound on a card; for fabrics, they should be taken from the fabric sample without creases or distortions. The standard recommends that each specimen be large enough to allow assessment of colour change over an area of at least 20 mm × 20 mm. The blue wool references are typically supplied as standards and should be stored in light-tight conditions prior to use.
Assessment of Colour Change
After exposure, the change in colour of the specimen is assessed visually using a grey scale for assessing change in colour (CGSB 4.2 No. 44 or ISO 105-A02). The colourfastness rating is the number of the blue wool standard that shows the same visual contrast between exposed and unexposed portions, or the rating computed from the grey scale. The standard allows the use of spectrophotometric evaluation as an alternative, provided the correlation to visual assessment is documented.
Best Practice: For critical colour assessments, always use a light booth with a standard daylight source (D65) and a viewing angle of 45° to the specimen. Multiple observers should be used to minimize subjectivity.
Caution: Some textiles may exhibit photochromism (colour change during exposure that reverses in the dark). CAN CGSB 4.2 No. 49-99 (2013) requires that such materials be assessed after conditioning in the dark for at least 2 hours before final evaluation.
Compliance Notes
Accreditation and Training
Testing performed according to CAN CGSB 4.2 No. 49-99 (2013) should be conducted by laboratories accredited under a recognized framework, such as ISO/IEC 17025. Personnel must be trained in the operation of xenon arc equipment, preparation of reference materials, and visual or instrumental assessment of colour change. Regular interlaboratory proficiency testing is recommended to ensure consistency across testing facilities.
Reporting Results
The test report must include the following elements: identification of the material tested, reference to this standard, the exposure condition used (normal or high humidity), the duration of exposure, the rating obtained (e.g., colourfastness grade 5), and any observed anomalies (e.g., photochromism, staining of adjacent fabrics). The report should also note the specific blue wool standards used and the type of grey scale employed for assessment.
Compliance with the standard is verified by comparing the reported colourfastness grade against product specifications or performance requirements established by the buyer, regulatory body, or industry standard. Typical pass/fail criteria may specify a minimum grade of 4 for apparel textiles, 5 for automotive interior fabrics, or 6 for outdoor and high-exposure textiles.
Regulatory Note: CAN CGSB 4.2 No. 49-99 (2013) is referenced in some Canadian consumer goods safety regulations for textile products. Manufacturers should verify current regulatory requirements with the applicable government agency.
Frequently Asked Questions
Q: What is the difference between CAN CGSB 4.2 No. 49-99 (2013) and ISO 105-B02?
A: CAN CGSB 4.2 No. 49-99 (2013) is the Canadian adoption that includes modifications to better reflect Canadian environmental exposure conditions, including optional high-humidity test cycles. The test method and equipment are essentially identical, but the Canadian standard provides specific guidance for local textile products and includes references to other CGSB test methods in the same series.
A: CAN CGSB 4.2 No. 49-99 (2013) is the Canadian adoption that includes modifications to better reflect Canadian environmental exposure conditions, including optional high-humidity test cycles. The test method and equipment are essentially identical, but the Canadian standard provides specific guidance for local textile products and includes references to other CGSB test methods in the same series.
Q: How do I interpret the colourfastness grade (e.g., grade 4 vs. grade 6)?
A: The colourfastness grade corresponds to the number of the blue wool reference that shows an equal change in colour after exposure. A higher grade indicates better colourfastness. Grade 4 is often considered minimum for general textile products, while grade 6 or higher is required for exterior applications or items requiring extended durability.
A: The colourfastness grade corresponds to the number of the blue wool reference that shows an equal change in colour after exposure. A higher grade indicates better colourfastness. Grade 4 is often considered minimum for general textile products, while grade 6 or higher is required for exterior applications or items requiring extended durability.
Q: Can I use a carbon arc lamp instead of a xenon arc lamp for this test?
A: No. CAN CGSB 4.2 No. 49-99 (2013) specifies the use of a xenon arc lamp filtered to simulate daylight. Carbon arc lamps are not approved for this method because their spectral output differs significantly from natural daylight, especially in the ultraviolet region, leading to different fading results.
A: No. CAN CGSB 4.2 No. 49-99 (2013) specifies the use of a xenon arc lamp filtered to simulate daylight. Carbon arc lamps are not approved for this method because their spectral output differs significantly from natural daylight, especially in the ultraviolet region, leading to different fading results.
Q: Is the standard still current after the year 2013?
A: Yes, as of 2025, CAN CGSB 4.2 No. 49-99 (2013) remains the current version. CGSB standards are reviewed periodically, and users should check for any amendments or reaffirmations. The standard number includes the original approval year (1999) and the reaffirmation or update year (2013).
A: Yes, as of 2025, CAN CGSB 4.2 No. 49-99 (2013) remains the current version. CGSB standards are reviewed periodically, and users should check for any amendments or reaffirmations. The standard number includes the original approval year (1999) and the reaffirmation or update year (2013).
Article prepared for technical reference purposes. Always consult the latest official version of the standard from the Canadian General Standards Board for authoritative requirements. References to other standards such as ISO 105-B02, CGSB 4.2 No. 44, and CGSB 4.2 No. 48 should be cross-checked for current editions. | Last updated: 2026