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CAN CGSB 4.2 No. 52.2-2013: Textile Test Methods — Colourfastness to Light: Xenon Arc Lamp
Standardized Procedure for Evaluating Lightfastness of Textiles Using Xenon Arc Exposure
CAN CGSB 4.2 No. 52.2-2013 is a test method developed by the Canadian General Standards Board as part of the CGSB 4.2 series of textile test methods. This standard specifically addresses the determination of colourfastness of textile materials of all kinds and in all forms to the action of artificial light, using a xenon arc lamp apparatus. It is widely referenced in Canadian textile specifications and procurement requirements, and it aligns closely with international methods such as ISO 105-B02 and AATCC TM 16.3. The 2013 edition incorporates updates to exposure conditions, reference materials, and instrument calibration to improve reproducibility and correlation with natural daylight exposure.
Scope and Application
The standard applies to textiles including fibres, yarns, fabrics, and finished articles. It is designed to simulate the colour change that may occur when materials are exposed to sunlight or other light sources under controlled conditions. The test is performed using a xenon arc lamp equipped with suitable filters to simulate the spectral distribution of natural daylight, typically D65. The method covers both intermittent light–dark cycles and continuous exposure, depending on the intended end-use environment.
CAN CGSB 4.2 No. 52.2-2013 is used for:
- Quality control during textile production
- Verification of supplier compliance with colourfastness specifications
- Product development and material selection
- Certification programs requiring lightfastness data
The method is applicable to all textiles, including those that have been dyed, printed, or otherwise treated. For materials that are sensitive to heat or moisture, the standard provides alternative exposure conditions.
Technical Requirements and Test Procedure
Specimen Preparation
Specimens are prepared by cutting representative samples from the textile material. Where possible, multiple test specimens are mounted on a backing card. The standard recommends using a specimen size of at least 45 mm × 125 mm, though alternative dimensions are permitted if necessary to accommodate the sample holder. The specimen should be kept flat and taut, and if the textile is a yarn, it is wound uniformly on a suitable holder.
For comparison and rating, two sets of blue wool reference standards (grades 1 to 8) are exposed alongside the test specimens. These references provide a calibrated scale of fading against which the colour change of the specimen can be assessed.
Exposure Conditions
The xenon arc lamp is operated under defined irradiance, temperature, and relative humidity conditions. The standard specifies two main exposure cycles:
| Parameter | Cycle A (Standard) | Cycle B (High Humidity) |
|---|---|---|
| Irradiance (at 420 nm) | 1.10 ± 0.03 W/m²·nm | 1.10 ± 0.03 W/m²·nm |
| Black standard temperature | 50 ± 3°C | 40 ± 3°C |
| Relative humidity in chamber | 40 ± 5% | 80 ± 5% |
| Light/dark cycle | Continuous light | 18 h light / 6 h dark |
| Duration | Until specified contrast or reference fade | Until specified contrast or reference fade |
The xenon arc lamp is filtered using a combination of soda lime glass and borosilicate glass (or a single filter with equivalent spectral cut‑off) to approximate the UV portion of natural daylight. A calibrated reference detector monitors irradiance and triggers automatic lamp control.
Assessment of Colour Change
After exposure, the specimen is removed and conditioned at standard atmospheric conditions (21 ± 1°C, 65 ± 4% RH) for at least 2 hours. The colour change is assessed visually by comparing the exposed area of the specimen with the unexposed original, using the grey scale for colour change (as per CGSB 4.2 No. 41). Alternatively, instrumental colour measurement (spectrophotometer) may be used, provided the measurement conditions (illuminant, observer, geometry) are reported.
The test result is reported as a rating from 1 (very poor colourfastness) to 5 (excellent colourfastness) based on the grey scale, or as the blue wool grade at which the specimen shows a just noticeable colour change. The standard requires that the blue wool reference used for each test be recorded, along with the exposure cycle and any deviations from standard conditions.
Tip: When using instrumental assessment, ensure that the spectrophotometer is set to D65 illuminant and 10° observer to match the conditions of visual assessment. Regular calibration with a white tile and a UV filter is essential for accurate readings.
Implementation Highlights
Implementing CAN CGSB 4.2 No. 52.2-2013 in a testing laboratory requires careful attention to equipment specification and maintenance. The xenon arc exposure apparatus must be equipped with:
- A quartz or borosilicate inner filter and a soda lime glass outer filter (or equivalent combination) to achieve the required spectral distribution.
- An irradiance control system that maintains the set point within ±5%.
- A black standard thermometer to monitor specimen temperature.
- A humidity sensor and control system for wet and dry bulb conditions.
Blue wool references should be purchased from a certified supplier and stored in the dark at a temperature below 30°C. Each batch of references should be validated against a master set to confirm that the fading behavior matches the nominal grade.
Warning: Failure to replace the UV filters after the manufacturer’s recommended operating hours (typically 2000 h) can lead to a shift in the spectral output, causing erroneous fading rates. Keep a log of filter usage and calibration dates.
For production environments, it is common to conduct periodic interlaboratory comparisons to confirm consistency across different testing facilities. The standard encourages participation in proficiency testing programmes.
Success: Laboratories that follow the calibration and maintenance schedule closely report lower variability and a higher correlation between artificial and natural exposure tests. This builds confidence in product certification.
Compliance and Reporting
When reporting results in accordance with CAN CGSB 4.2 No. 52.2-2013, the test report must include the following information:
- Reference to the standard (CAN CGSB 4.2 No. 52.2-2013)
- Description of the textile material tested
- Exposure cycle used (A or B)
- Irradiance level, temperature, and relative humidity
- Duration of exposure or the number of hours until the reference faded
- Blue wool grade(s) used
- Assessment method (visual grey scale or instrument) and the rating obtained
- Any deviations from the standard procedure
The standard requires that if a specific blue wool grade is required by a product specification (e.g., minimum grade 4), the test must be conducted until that reference fades to a specified contrast. In such cases, the result is reported as “pass” if the specimen shows less colour change than the reference, or “fail” if it shows more.
Important: Only test results that strictly follow the exposure and assessment criteria of the standard should bear the claim “tested according to CAN CGSB 4.2 No. 52.2-2013.” Modifications, such as using a different filter combination or omitting humidity control, invalidate the compliance statement.
For textile products intended for outdoor applications (e.g., automotive interiors, awnings, marine fabrics), a more stringent requirement may be imposed, such as a minimum blue wool grade of 6 after 100 hours of exposure. The standard does not set pass/fail criteria; these are defined by the contracting parties or by reference in provincial or federal regulations.
Frequently Asked Questions
Q: Is CAN CGSB 4.2 No. 52.2-2013 identical to ISO 105-B02?
A: They are technically equivalent in most respects, but some differences exist in the specification of filter types and the definition of humidity control. Laboratories certified to ISO standards often find it straightforward to extend their scope to cover this Canadian standard.
A: They are technically equivalent in most respects, but some differences exist in the specification of filter types and the definition of humidity control. Laboratories certified to ISO standards often find it straightforward to extend their scope to cover this Canadian standard.
Q: Can I use a carbon arc lamp instead of a xenon arc lamp?
A: No. This standard specifically requires a xenon arc lamp with daylight filters. Carbon arc lamps produce a different spectral distribution and are covered by other methods (e.g., CGSB 4.2 No. 52.1).
A: No. This standard specifically requires a xenon arc lamp with daylight filters. Carbon arc lamps produce a different spectral distribution and are covered by other methods (e.g., CGSB 4.2 No. 52.1).
Q: How often should the blue wool references be replaced?
A: Blue wool references should be replaced once opened after six months, or earlier if stored improperly. Unopened sets stored in a cool, dark place can be used until the expiry date indicated by the manufacturer.
A: Blue wool references should be replaced once opened after six months, or earlier if stored improperly. Unopened sets stored in a cool, dark place can be used until the expiry date indicated by the manufacturer.
Q: What is the recommended number of specimens per test?
A: The standard recommends a minimum of two specimens. For critical evaluations or when the material shows high variability, three or more specimens should be tested, and the average rating reported.
A: The standard recommends a minimum of two specimens. For critical evaluations or when the material shows high variability, three or more specimens should be tested, and the average rating reported.
CAN CGSB 4.2 No. 52.2-2013 remains an essential standard for the Canadian textile industry, providing a reliable basis for lightfastness evaluation. Its close alignment with international methods facilitates trade while accommodating specific Canadian climatic considerations. Laboratories that adopt this standard benefit from clear guidance on equipment, procedures, and reporting, ensuring consistent and comparable results across the supply chain.
Update: 2026