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CAN/CGSB-4.2 No. 6‑2013: Colourfastness to Washing and Bleaching — Technical Overview and Compliance Considerations
Comprehensive analysis of the Canadian standard for evaluating textile colourfastness under domestic and commercial laundering conditions
The standard CAN/CGSB‑4.2 No. 6‑2013, titled Textile Test Methods – Colourfastness to Washing and Bleaching, is a cornerstone document in the Canadian textile testing framework developed by the Canadian General Standards Board (CGSB). It specifies a laboratory method for determining the resistance of the colour of textiles to the combined action of washing and bleaching agents under conditions that simulate domestic and commercial laundering. The method is widely cited in quality control protocols, product certification schemes, and procurement specifications throughout Canada and is harmonized with international practice.
Scope and Application
This standard is applicable to all textile materials in any form (fibre, yarn, fabric, or finished article). Its primary purpose is to evaluate colourfastness to washing and bleaching, including the effect of mechanical action, detergent solutions, and oxidizing bleach (chlorine‑based or perborate/peracetic acid systems). The test covers a range of temperature and time combinations that correspond to typical laundering cycles. The standard does not address the assessment of dimensional change or other physical properties; it is strictly a colourfastness method.
The method is often used as a pass/fail criterion in product specifications, for colour consistency checks between production lots, and as a tool in dye and chemical selection during product development. It is particularly relevant for garments, household textiles, and industrial fabrics that are subjected to repeated laundering with bleach.
Harmonization note: CAN/CGSB‑4.2 No. 6‑2013 is technically equivalent to ISO 105‑C06:2010, facilitating mutual recognition of test results between Canada and international trading partners.
Technical Requirements and Test Conditions
Principle of the Method
A specimen of the textile, in contact with specified adjacent fabrics, is washed in a rotating container under controlled conditions of temperature, time, detergent concentration, and, optionally, bleach. After washing, rinsing, and drying, the colour change of the specimen and the staining of the adjacent fabrics are assessed using grey scales.
Apparatus and Reagents
- Washing machine: A rotating‑container apparatus (e.g., Launder‑Ometer or equivalent) capable of maintaining the specified temperature ±2 °C and rotating at 40 ± 2 rpm.
- Steel cans: Stainless steel or glass containers of 500 mL or 1000 mL capacity with tight‑sealing lids.
- Reference detergent: A non‑phosphate reference detergent defined in the standard (similar to ECE reference detergent 01).
- Bleach systems: Active chlorine (sodium hypochlorite) or sodium perborate tetrahydrate with tetraacetylethylenediamine (TAED) activator.
- Adjacent fabrics: Multifibre test fabric (e.g., DW type) or single‑fibre fabrics to evaluate staining.
- Grey scales: Grey scale for colour change (ISO 105‑A02) and grey scale for staining (ISO 105‑A03).
Test Procedures
The standard defines a series of washing procedures covering a range of severity. Each procedure is designated by a code (e.g., A1, A2, B1, B2, C1, D1). The table below summarizes the key parameters of the most commonly used procedures:
| Procedure | Temperature (°C) | Time (min) | Bleach Type | Bleach Concentration* | Liquor Ratio |
|---|---|---|---|---|---|
| A1 | 40 | 30 | None | — | 50 :1 |
| A2 | 40 | 30 | Active Cl | 0.1 % active Cl | 50 :1 |
| B1 | 60 | 30 | None | — | 50 :1 |
| B2 | 60 | 55 | Perborate/TAED | 0.2 % H2O2 equiv. | 50 :1 |
| C1 | 95 | 30 | None | — | 50 :1 |
| D1 | 95 | 55 | Active Cl | 0.15 % active Cl | 50 :1 |
* Concentration based on liquor volume. Users may adjust levels per specification.
Specimen Preparation and Test Execution
Specimens are cut to 100 mm × 40 mm, with the long dimension parallel to the warp or length direction. Adjacent fabrics are attached by sewing. The combined assembly is placed in a steel can with the required volume of washing solution (containing detergent and, if applicable, bleach) along with steel balls for mechanical action. The can is sealed and rotated in the preheated apparatus for the prescribed time.
Tip: Always use the specified number of steel balls (e.g., 10 balls per 500 mL can) to ensure consistent mechanical action. Variation in ball quantity can significantly alter results.
Implementation and Interpretation of Results
Evaluation of Colour Change and Staining
After washing, the specimen is rinsed in cold water, gently squeezed, and dried at a temperature not exceeding 60 °C. Assessment is performed in a standard viewing cabinet (D65 illuminant). The colour change of the specimen is rated against the grey scale for colour change, where class 5 indicates no change and class 1 indicates severe change. The staining on each adjacent fabric is rated using the grey scale for staining. The reported result typically includes the colour change class and the staining class for each adjacent fibre type.
Choosing the Appropriate Procedure
The choice of procedure depends on the expected laundering severity and the type of product. For example:
- A1 — Gentle wash, suitable for delicate fabrics.
- A2 — Similar to A1 but with chlorine bleach.
- B1 — Moderate wash, typical for durable fabrics.
- B2 — Moderate wash with perborate bleach, common in European formulations.
- C1/D1 — Severe commercial laundering conditions.
Many procurement specifications require a minimum rating (e.g., colour change ≥ 4 and staining ≥ 3‑4) for a given procedure.
Safety caution: When handling bleach solutions (especially active chlorine), always work in a well‑ventilated area and use appropriate personal protective equipment. Bleach solutions should be prepared fresh before each test to maintain consistent concentration.
Compliance Notes and Quality Assurance
Accredited testing laboratories (e.g., SCC‑accredited) follow this standard as part of textile certification programs. Key compliance points include:
- Verification of reagents: The reference detergent and bleach must be from approved sources or analysed to confirm composition. Variation in detergent activity can cause offsets in results.
- Calibration of equipment: The washing apparatus temperature and rotation speed must be calibrated regularly, with records maintained.
- Proficiency testing: Laboratories are encouraged to participate in periodic interlaboratory comparisons, such as those organised by CGSB or ASTM, to ensure reproducibility.
- Sample conditioning: Specimens should be conditioned in a standard atmosphere (20 ± 2 °C, 65 ± 4 % RH) before testing, though colourfastness is generally not sensitive to humidity.
Important limitation: This test method simulates accelerated laundering. It may not perfectly replicate real‑life, multi‑cycle wear and wash exposure, especially for reactive dyes on cellulosic fibres or for finishes that degrade over time. Therefore, results should be interpreted in conjunction with other performance criteria.
As of 2026, CAN/CGSB‑4.2 No. 6‑2013 remains the current version of the standard and is referenced in numerous Canadian federal procurement requirements, notably for uniforms and institutional textiles. It is also recognized by the Canadian General Standards Board as part of the broader Textile Test Methods series (CGSB‑4.2). Users should always verify the latest edition when updating internal specifications or regulatory submissions.
Frequently Asked Questions
Q: How does CAN/CGSB‑4.2 No. 6‑2013 relate to ISO 105‑C06?
A: The two standards are technically identical in terms of test procedures, apparatus, and rating scales. The Canadian standard includes minor editorial differences and references CGSB‑specific documents. For most practical purposes, results obtained by either method are directly comparable, provided the same procedure code (e.g., A1, B2) is used.
A: The two standards are technically identical in terms of test procedures, apparatus, and rating scales. The Canadian standard includes minor editorial differences and references CGSB‑specific documents. For most practical purposes, results obtained by either method are directly comparable, provided the same procedure code (e.g., A1, B2) is used.
Q: Which procedure should I use for “heavy‑duty” household laundry?
A: Procedure B1 (60 °C, 30 min) is generally considered representative of typical heavy‑duty home washing. If bleach is used, B2 (with perborate/TAED system) is appropriate. For bleach‑containing detergents, A2 or D1 might be specified depending on the wash temperature.
A: Procedure B1 (60 °C, 30 min) is generally considered representative of typical heavy‑duty home washing. If bleach is used, B2 (with perborate/TAED system) is appropriate. For bleach‑containing detergents, A2 or D1 might be specified depending on the wash temperature.
Q: Can I reuse the washing solution or steel balls between tests?
A: No. The washing solution must be freshly prepared for each test to ensure consistent active chemical concentration. Steel balls should be thoroughly cleaned (rinsed, dried) between tests and discarded if they show signs of corrosion or pitting.
A: No. The washing solution must be freshly prepared for each test to ensure consistent active chemical concentration. Steel balls should be thoroughly cleaned (rinsed, dried) between tests and discarded if they show signs of corrosion or pitting.
Q: Is the test suitable for evaluating the effect of pre‑treatment stain removers?
A: The standard method focuses on a single combined washing/bleaching step. It does not model pre‑treatment or multiple‑wash cycles. For such evaluations, supplementary test procedures (e.g., CGSB 4.2 No. 36 or custom protocols) may be necessary.
A: The standard method focuses on a single combined washing/bleaching step. It does not model pre‑treatment or multiple‑wash cycles. For such evaluations, supplementary test procedures (e.g., CGSB 4.2 No. 36 or custom protocols) may be necessary.
© 2026 – This article is intended for informational purposes. For official compliance, refer to the current edition of CAN/CGSB‑4.2 No. 6‑2013 from the Canadian General Standards Board.