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CAN CGSB 4.175-M87 Part 1: Standard Test Method for Colourfastness to Washing of Textiles
Technical Overview of the Canadian General Standards Board Method for Determining Dye Stability Under Controlled Laundering Conditions
The CAN CGSB 4.175-M87 Part 1 standard, published by the Canadian General Standards Board, specifies a test method for determining the colourfastness of textiles to washing. This method simulates the effects of a single domestic or commercial laundering cycle and evaluates both colour change in the specimen and staining of adjacent fabrics. It is widely referenced for quality control within the Canadian textile industry and aligns with international principles for reproducibility and accuracy.
1. Scope and Purpose
CAN CGSB 4.175-M87 Part 1 applies to all textile materials and their colourants, including dyes and pigments, in any form (fibre, yarn, fabric, or finished product). The test is intended to assess resistance to washing under defined conditions of temperature, mechanical action, detergent concentration, and time. It does not cover dry-cleaning or spot-cleaning procedures. The standard is part of a multi-part series; Part 1 specifically focuses on the single-cycle wash test that replicates typical home laundry conditions.
The purpose of the method is to provide a reliable, reproducible basis for comparing the colourfastness of different textiles. Results guide product development, specification compliance, and consumer information. The standard is also used in conjunction with assessment scales that quantify colour change and staining, such as the grey scale for colour change (ISO 105-A02) and the grey scale for staining (ISO 105-A03), although these are referenced externally.
TIP: Always condition test specimens in a standard atmosphere (20 ± 2 °C, 65 ± 4 % RH) for at least 4 hours before testing to minimize the influence of ambient humidity on dye behaviour.
2. Technical Requirements
2.1 Apparatus and Materials
The following major equipment is required:
- A wash container with rotating shaft and bath capable of maintaining the specified test temperature within ± 2 °C .
- Stainless steel balls of specified diameter (6 mm) to simulate mechanical agitation.
- Multi-fibre adjacent fabric strip (as per ISO 105-F10) or single-fibre fabrics for staining assessment.
- Laboratory balance accurate to ± 0.01 g, pH meter, and thermometer with ± 0.5 °C accuracy.
2.2 Reagents and Detergent
The standard detergent composition is specified, typically a reference detergent without optical brighteners. The concentration depends on the test condition selected. Water used must be distilled or deionized with conductivity not exceeding 0.5 mS/m at 25 °C.
2.3 Test Specimen Preparation
A specimen of 100 mm × 40 mm is cut from the textile. A multi-fibre adjacent fabric of the same size is attached along one long side. The combined specimen is then placed in a stainless steel container with the required volume of detergent solution and steel balls, if specified.
2.4 Test Procedure and Conditions
The test involves washing the specimen in a rotating bath under one of several standard conditions. The table below lists the conditions commonly adopted in Part 1:
| Condition | Temperature (°C) | Duration (min) | Steel Balls (quantity) | Detergent Conc. (g/L) |
|---|---|---|---|---|
| A1 | 40 ± 2 | 30 | 0 | 4 |
| A2 | 40 ± 2 | 30 | 10 | 4 |
| B1 | 50 ± 2 | 45 | 0 | 5 |
| B2 | 50 ± 2 | 45 | 10 | 5 |
| C2 | 60 ± 2 | 30 | 10 | 5 |
| D2 | 70 ± 2 | 30 | 10 | 5 |
| E2 | 95 ± 2 | 30 | 10 | 5 |
After the wash cycle, the specimen is removed, rinsed, dried, and conditioned before assessment.
2.5 Assessment of Colour Change and Staining
The colour change of the specimen is assessed using a grey scale (e.g., ISO 105-A02) under standard daylight. The staining on each adjacent fabric is evaluated using the grey scale for staining (e.g., ISO 105-A03). Results are reported as numerical ratings (1 = severe change/staining, 5 = no change/staining). All assessments must be conducted by trained observers under controlled lighting conditions (e.g., D65 illuminant).
WARNING: The selection of a test condition should reflect the intended end-use of the textile. Conditions A1 or A2 are suitable for delicate fabrics, while E2 represents severe home laundering. Using a condition too severe may yield misleadingly poor ratings for products that will only experience mild washing.
3. Implementation Considerations
Laboratories implementing CAN CGSB 4.175-M87 Part 1 must ensure that the wash bath has uniform temperature control and that rotational speed is within the specified range (typically 40 ± 2 rpm). The use of steel balls must be consistent, as they affect the mechanical action. Pre-wetting the specimen in distilled water at room temperature for 5 minutes improves wetting uniformity. The detergent solution must be preheated to test temperature before adding the specimen-composite to ensure the entire test duration occurs at the designated temperature.
Inter-laboratory reproducibility depends on strict adherence to the defined parameters. Any deviation in detergent composition, water hardness, or drying method significantly affects results. Therefore, it is recommended that participating laboratories run regular proficiency tests and calibrate equipment at defined intervals.
The standard also notes that if the textile contains finishes that may be removed or altered by the wash (e.g., temporary stiffeners), these should be recorded and considered when interpreting results.
GOOD PRACTICE: Maintain a detailed log of test conditions, equipment calibration dates, and observer training records. This supports traceability and strengthens compliance with quality management systems such as ISO 17025.
4. Compliance and Certification Notes
CAN CGSB 4.175-M87 Part 1 is often referenced in Canadian government procurement contracts and by consumer protection agencies. Products that meet specified colourfastness criteria based on this standard may be labelled accordingly, provided that the testing is performed by an accredited laboratory. The standard does not itself define pass/fail limits; instead, these are set by the product specification or regulatory authority. Common acceptable ratings are typically ≥ 3.5 for colour change and ≥ 3 for staining.
It is important to note that the standard is periodically reviewed; while the current edition remains at 1987, users should verify whether a more recent part exists for the specific test needed (e.g., Part 2 for multiple washes or Part 3 for chlorinated water). Compliance documents should state the standard reference exactly as CAN CGSB 4.175-M87 Part 1, along with the specific test condition (e.g., B2) and the rating obtained.
CAUTION: Mixing conditions or scaling procedures from other standards (e.g., ISO 105-C06) without cross-validation may result in non-compliant data. Always follow the exact specifications of CAN CGSB 4.175-M87 Part 1 for certification purposes.
Frequently Asked Questions
Q: What is the main difference between Part 1 and other parts of CAN CGSB 4.175-M87?
A: Part 1 covers a single wash cycle under defined conditions, while later parts address multiple cycles (Part 2) or special treatments such as chlorinated water and peroxide bleaching (Parts 3 and 4). The choice depends on the expected end-use of the textile.
A: Part 1 covers a single wash cycle under defined conditions, while later parts address multiple cycles (Part 2) or special treatments such as chlorinated water and peroxide bleaching (Parts 3 and 4). The choice depends on the expected end-use of the textile.
Q: Can I substitute a different adjacent fabric if the specified one is not available?
A: No. The standard requires the use of a multi-fibre adjacent fabric (e.g., ISO 105-F10) or specific single-fibre fabrics to ensure consistent staining assessment. Any substitution would void the method’s validity and comparability.
A: No. The standard requires the use of a multi-fibre adjacent fabric (e.g., ISO 105-F10) or specific single-fibre fabrics to ensure consistent staining assessment. Any substitution would void the method’s validity and comparability.
Q: How does water hardness affect test results?
A: Water hardness can significantly alter detergent effectiveness and dye solubility. The standard mandates the use of distilled or deionized water to avoid such effects. If hard water is used unintentionally, results may show greater staining or reduced colour change ratings.
A: Water hardness can significantly alter detergent effectiveness and dye solubility. The standard mandates the use of distilled or deionized water to avoid such effects. If hard water is used unintentionally, results may show greater staining or reduced colour change ratings.
Q: Is CAN CGSB 4.175-M87 Part 1 still current even though it was published in 1987?
A: Yes, the standard remains active and is maintained by the Canadian General Standards Board. However, users should check for any amendments or companion parts that might supersede specific sections. Many Canadian specifications still reference this edition for single‑wash colourfastness testing.
A: Yes, the standard remains active and is maintained by the Canadian General Standards Board. However, users should check for any amendments or companion parts that might supersede specific sections. Many Canadian specifications still reference this edition for single‑wash colourfastness testing.
Article prepared in 2026. This information is for educational purposes and does not replace the official text of CAN CGSB 4.175-M87 Part 1.