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Understanding CAN CGSB 4.155-M88 (2013): The Canadian Standard for Colourfastness to Light Testing in Textiles
A comprehensive guide to the scope, technical requirements, and compliance framework of Canada’s primary standard for assessing textile colourfastness to light.
CAN CGSB 4.155-M88 (2013) is the definitive Canadian standard for evaluating the colourfastness of textiles to light. Developed by the Canadian General Standards Board (CGSB) and reaffirmed in 2013, this test method provides a consistent and reliable procedure to determine how well textile colours resist fading when exposed to both natural and artificial light sources. The standard is widely referenced by Canadian manufacturers, retailers, and regulatory bodies to ensure textile products meet the durability expectations of consumers. This article explores the scope, technical requirements, implementation considerations, and compliance framework of CAN CGSB 4.155-M88 (2013).
Scope and Purpose
CAN CGSB 4.155-M88 (2013) specifies a method for determining the resistance of the colour of textiles to the action of light. The method is intended for all kinds of textiles — including woven, knitted, nonwoven, and coated fabrics — used in apparel, home furnishings, automotive interiors, and outdoor applications. The purpose of the standard is to simulate the fading effect of daylight, including its ultraviolet (UV) component, under controlled conditions that allow reproducible and comparable results.
The test method is based on the simultaneous exposure of test specimens and a series of eight blue wool reference standards to a specified light source. After exposure, the colour change of the specimen is assessed visually or instrumentally against the reference standards. The outcome is a lightfastness rating on a scale of 1 (poor) to 8 (excellent). This rating enables manufacturers to classify textiles according to their expected performance in end-use environments, from low light exposure (e.g., indoor apparel) to high UV exposure (e.g., outdoor furniture).
Tip: The eight blue wool reference standards are produced according to a strict specification; they should be purchased from an approved supplier and stored in a dark, cool, and dry environment to maintain their integrity.
Technical Requirements and Test Method
Principle of the Test
Specimens of the textile being tested are mounted on a specimen holder together with the eight blue wool reference standards. The assembly is exposed under controlled conditions to a light source that simulates daylight. The exposure is continued until the colour change of one of the reference standards reaches the specified contrast (typically visual change equal to Step 4 on the Grey Scale). The colour change of the test specimen is then compared to that of the reference standards, and the lightfastness rating is assigned equal to the number of the reference standard that shows a similar colour change.
Light Source and Exposure Conditions
The standard requires a xenon-arc lamp as the artificial light source, fitted with daylight filters to reproduce the spectral energy distribution of average daylight (with UV component). The apparatus must conform to the specifications of CGSB 4.GP-28M, which details the geometry, temperature control, and irradiance measurement. The following exposure conditions are prescribed:
- Black standard temperature: 47 ± 2 °C
- Relative humidity: 30 ± 5 %
- Irradiance: 1.10 ± 0.03 W/(m²·nm) at 420 nm
- Exposure cycle: Continuous light with periodic dark cycles if humidity control is disrupted
Evaluation and Rating
After exposure, the specimens are compared to the reference standards and the grey scale. The rating is recorded as the number of the reference standard that exhibits the same degree of colour change. If the colour change falls between two standards, an intermediate rating (e.g., 3-4) may be reported. The table below summarizes the lightfastness ratings and their typical applications.
| Rating | Blue Wool Standard No. | Typical Application Examples |
|---|---|---|
| 1 | 1 | Very low lightfastness – fugitive colours, decorative items not exposed to light |
| 2 | 2 | Low lightfastness – interior textiles with minimal light exposure |
| 3 | 3 | Moderate lightfastness – basic apparel, accessories |
| 4 | 4 | Average lightfastness – general apparel, curtains (limited UV) |
| 5 | 5 | Good lightfastness – window treatments, upholstery |
| 6 | 6 | Very good lightfastness – automotive interior textiles |
| 7 | 7 | Excellent lightfastness – outdoor textiles, marine fabrics |
| 8 | 8 | Outstanding lightfastness – extreme UV environments, long-life products |
Warning: The test results are highly sensitive to humidity control. Do not deviate from the specified relative humidity; otherwise, the fading rate may change and produce non-comparable ratings.
Implementation and Equipment Considerations
To successfully implement the CAN CGSB 4.155-M88 (2013) method, laboratories must invest in precise equipment and maintain rigorous calibration procedures. Key considerations include:
- Xenon-arc apparatus: The instrument must be equipped with daylight filters and comply with CGSB 4.GP-28M. Regular lamp replacement and spectral output verification are essential.
- Humidity and temperature control: Use of a chilled mirror hygrometer or equivalent sensor is recommended. The apparatus should be calibrated at least annually.
- Reference materials: The blue wool standards (SDC or equivalent) have a limited shelf life; replace them according to manufacturer instructions.
- Specimen preparation: Test specimens must be preconditioned at standard atmosphere (21 ± 1 °C, 65 ± 4 % RH) for at least 4 hours before testing. Multiple specimens per sample are recommended to ensure statistical validity.
The standard also permits the use of natural daylight as an alternative light source, but the xenon-arc method is more commonly used due to its reproducibility and shorter test duration. Laboratories that choose natural daylight must adhere to specific geographic and seasonal requirements outlined in the standard.
Note: CAN CGSB 4.155-M88 (2013) is harmonized with ISO 105-B02:2014 for the xenon-arc method, but it includes additional exposure duration options that reflect Canadian climatic conditions (e.g., northern UV intensity).
Critical: Never expose specimens that have not been preconditioned. Moisture variations in unconditioned samples can dramatically alter fading rates and invalidate the test.
Compliance and Certification Notes
While CAN CGSB 4.155-M88 (2013) is a voluntary standard in Canada, it is frequently incorporated by reference in commercial contracts, retailer specifications, and procurement documents. Many Canadian government departments and large retailers (e.g., for uniforms, military textiles, or public transit seating) require compliance with this standard as part of their quality assurance.
Testing must be performed by laboratories accredited to ISO/IEC 17025 with specific scope for CGSB test methods. The accreditation bodies in Canada include the Standards Council of Canada (SCC) and the Canadian Association for Laboratory Accreditation (CALA). The test report must include the following elements:
- The designation CAN CGSB 4.155-M88 (2013)
- The light source used (xenon-arc or daylight)
- The exposure cycle and conditions (temperature, humidity, irradiance)
- The rating for each specimen, with any intermediate values
- A statement of compliance or non-compliance with a specified rating
Manufacturers are advised to set internal lightfastness targets based on product end-use. For example, indoor curtains may require a minimum rating of 5, while outdoor furniture fabrics should achieve at least 6. The reaffirmation of the standard in 2013 confirms its continued relevance and acceptance within the industry. It is recommended that users verify with the CGSB whether any amendments or corrigenda have been issued since 2013.
Frequently Asked Questions
Q: What is the difference between CAN CGSB 4.155-M88 (2013) and ISO 105-B02?
A: Both standards use a xenon-arc lamp and blue wool references for lightfastness testing. The CGSB method includes specific exposure durations and conditions tailored to Canadian climate considerations (e.g., higher UV flux at northern latitudes). While the general test principle is similar, the rated performance levels may differ slightly, so the applicable standard must be referenced in specifications.
A: Both standards use a xenon-arc lamp and blue wool references for lightfastness testing. The CGSB method includes specific exposure durations and conditions tailored to Canadian climate considerations (e.g., higher UV flux at northern latitudes). While the general test principle is similar, the rated performance levels may differ slightly, so the applicable standard must be referenced in specifications.
Q: How is the lightfastness rating determined if the specimen fades unevenly?
A: If uneven fading occurs, the specimen should be evaluated at the area of greatest colour change. If the fading is associated with specimen construction (e.g., yarn dyeing variations), multiple specimens should be tested, and the lowest rating reported. The test report should note any anomalies.
A: If uneven fading occurs, the specimen should be evaluated at the area of greatest colour change. If the fading is associated with specimen construction (e.g., yarn dyeing variations), multiple specimens should be tested, and the lowest rating reported. The test report should note any anomalies.
Q: Is CAN CGSB 4.155-M88 (2013) mandatory for all textile products in Canada?
A: No, it is a voluntary standard. However, it is often required by contract or regulation for specific products (e.g., government procurement, children’s sleepwear, firefighter uniforms). Check with your buyer or relevant regulatory body for mandatory requirements.
A: No, it is a voluntary standard. However, it is often required by contract or regulation for specific products (e.g., government procurement, children’s sleepwear, firefighter uniforms). Check with your buyer or relevant regulatory body for mandatory requirements.
Q: Can this test be performed using a carbon-arc lamp?
A: The standard specifies a xenon-arc lamp with daylight filters as the primary artificial light source. Carbon-arc lamps, which have a different spectral distribution, are not recommended and would not produce results comparable to those obtained under the CGSB method. If carbon-arc is used, it must be noted, and the report cannot claim compliance with CAN CGSB 4.155-M88 (2013).
A: The standard specifies a xenon-arc lamp with daylight filters as the primary artificial light source. Carbon-arc lamps, which have a different spectral distribution, are not recommended and would not produce results comparable to those obtained under the CGSB method. If carbon-arc is used, it must be noted, and the report cannot claim compliance with CAN CGSB 4.155-M88 (2013).
© 2026 — Technical Reference Guide for CAN CGSB 4.155-M88 (2013). This article is for informational purposes and does not replace the official standard. For authoritative implementation, consult the current version published by the Canadian General Standards Board.