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CAN CGSB 4.2 No. 66-M91 (2013): Standard Test Method for Resistance of Textile Fabrics to Surface Wetting (Spray Test)
A comprehensive guide to the Canadian standard for evaluating the water repellency of textile fabrics using the spray test method.
1. Scope and Application
CAN CGSB 4.2 No. 66-M91 (2013), issued by the Canadian General Standards Board (CGSB), describes a spray test method for evaluating the resistance of textile fabrics to surface wetting (water repellency). This standard applies to woven, knit, and nonwoven fabrics, regardless of fiber content or finish, and is commonly used for apparel, upholstery, and technical textiles where initial repellency is critical. The test simulates a light rain or spray to assess how well a fabric repels water from its surface, providing a rating that correlates to the degree of wetting.
The standard is identical in technical content to AATCC 22 and is harmonized with ISO 4920, ensuring global consistency. It is referenced in product specifications, quality control programs, and certification schemes for water‑repellent finishes. The test is intended for fabrics that are not expected to be waterproof but must resist wetting during use.
2. Technical Requirements and Test Procedure
2.1 Apparatus and Materials
The test requires a standardized spray tester (also called a spray rating apparatus), consisting of a metal funnel (150 mm diameter), a ring stand to hold the fabric specimen at a 45° angle, and a spray nozzle that delivers 250 mL of distilled or deionized water at 27±1 °C over a period of 25–30 seconds. The water is poured into the funnel through the orifice to strike the fabric surface. Other apparatus include a beaker (250 mL), a graduated cylinder, and a conditioning room controlled at 21±1 °C and 65±2% relative humidity.
2.2 Specimen Preparation and Conditioning
Four test specimens, each 180 × 180 mm, are cut from the fabric sample, avoiding creases and selvages. Specimens are conditioned for at least 24 hours in the standard atmosphere (21±1 °C, 65±2% RH). The fabric is placed taut in the embroidery hoop (the holding frame) with the face side up, ensuring there are no wrinkles.
2.3 Test Procedure
The conditioned specimen is placed on the ring stand at 45°. The funnel is filled with 250 mL of distilled water at 27±1 °C, which is then poured into the spray nozzle. The water stream strikes the fabric’s centre, and the spray is completed in 25–30 seconds. Immediately after spraying, the hoop is removed, and the fabric is gently tapped twice against a solid object to remove excess water. The wetting pattern is compared to the photographic rating standards or a written description.
2.4 Spray Test Rating Scale
Ratings are assigned on a scale from 0 to 100, corresponding to the degree of wetting. A rating of 100 indicates no wetting; 90 indicates slight random wetting; 80 indicates wetting at the spray points; 70 indicates wetting of half the surface; 50 indicates complete wetting of the entire surface; 0 indicates complete wetting through the entire specimen. The intermediate ratings may be used (e.g., 85). The reported result is the median of four individual readings.
| Rating | Appearance After Spray | Interpretation |
|---|---|---|
| 100 | No sticking or wetting of the specimen face | Excellent repellency |
| 90 | Slight random sticking or wetting at a few points | Very good repellency |
| 80 | Wetting at the spray points on the face | Good repellency |
| 70 | Partial wetting of the entire face (half the surface) | Moderate repellency |
| 50 | Complete wetting of the entire face | Poor repellency |
| 0 | Complete wetting of both face and back | No repellency |
Tip: Condition specimens for at least 24 hours at standard conditions. Even small variations in humidity or temperature can affect the wetting characteristics and lead to inconsistent ratings.
Warning: Use only distilled or deionized water (conductivity ≤ 1 µS/cm). Tap water containing dissolved salts or surfactants will significantly alter surface tension and produce erroneous results.
3. Implementation Highlights
To achieve reliable and reproducible results, laboratories must strictly control the water temperature (27±1 °C) and the spray duration (25–30 seconds). The funnel height and angle are fixed; any deviation will affect impact pressure and wetting pattern. The rating should be assigned under consistent lighting (diffuse daylight or standardized artificial light) and by experienced operators to minimize subjectivity.
This standard is often used in conjunction with performance specifications (e.g., CAN/CGSB 4.2 No. 34) to define acceptable levels of repellency for finished goods. Manufacturers apply the test for quality control of water‑repellent finishes, process optimization, and product development. When evaluating fabrics containing durable water repellents (DWR), multiple laundering cycles may be required to assess durability; the standard itself does not include washing procedures, but complementary standards (e.g., CAN/CGSB 4.2 No. 58) can be used.
Compliance tip: Testing under this standard is accepted by major retailers and regulatory bodies in Canada. A rating of 80 or higher is typically required for garments sold as “water repellent”. Ensure your lab is accredited to ISO/IEC 17025 for recognition of competence in performing this test.
Misuse risk: The spray test does not measure resistance to water penetration under pressure (hydrostatic head) or fabric breathability. Applying the test to fabrics with a low surface tension (e.g., silicone‑coated or heavily oil‑finished textiles) may give misleadingly low ratings. Always refer to the specific product standard or contract for the correct test method.
4. Compliance and Record Keeping
When this standard is specified in a regulation or contract, testing shall be performed exactly as written. Deviations (e.g., using different water volume, temperature, or specimen orientation) must be documented as non‑standard conditions and may invalidate results. Test reports should include: reference to CAN CGSB 4.2 No. 66-M91 (2013), specimen identification, conditioning details, individual ratings, the median rating, and any observed anomalies (e.g., delamination or pilling).
Records of test results should be retained for at least three years or as required by the contracting authority. Proficiency testing programs (e.g., from CGSB or ASTM) are recommended to verify inter‑laboratory consistency. The standard was reaffirmed in 2013 and remains current; always verify the latest edition before testing.
FAQs
Q: Is CAN CGSB 4.2 No. 66-M91 (2013) identical to AATCC 22?
A: Yes. Both standards are technically equivalent and produce identical ratings. CGSB 4.2 No. 66-M91 is the Canadian adoption, while AATCC 22 is the American version. ISO 4920 also follows the same procedure, though minor differences in wording exist. Laboratories can use any of these standards interchangeably if the contract does not specify one exclusively.
A: Yes. Both standards are technically equivalent and produce identical ratings. CGSB 4.2 No. 66-M91 is the Canadian adoption, while AATCC 22 is the American version. ISO 4920 also follows the same procedure, though minor differences in wording exist. Laboratories can use any of these standards interchangeably if the contract does not specify one exclusively.
Q: What is the difference between the spray test and the rain test (e.g., AATCC 35)?
A: The spray test (CGSB 4.2 No. 66) evaluates surface wetting using a simulated light spray, while the rain test measures water penetration through the fabric under impact, typically using a more intense spray and a wicking material behind the specimen. The spray test is quicker and used for quality control of DWR finishes; the rain test is used for garment performance evaluation under simulated rainfall.
A: The spray test (CGSB 4.2 No. 66) evaluates surface wetting using a simulated light spray, while the rain test measures water penetration through the fabric under impact, typically using a more intense spray and a wicking material behind the specimen. The spray test is quicker and used for quality control of DWR finishes; the rain test is used for garment performance evaluation under simulated rainfall.
Q: Can the test be performed on fabrics with a pile or textured surface?
A: Yes, but caution is needed. Pile fabrics (e.g., fleece, velvet) may trap water and lead to lower ratings that do not reflect their actual performance in use. For such materials, special mounting techniques or alternative methods (e.g., the drop test, Moire method) may be more appropriate. Always check the applicable product specification.
A: Yes, but caution is needed. Pile fabrics (e.g., fleece, velvet) may trap water and lead to lower ratings that do not reflect their actual performance in use. For such materials, special mounting techniques or alternative methods (e.g., the drop test, Moire method) may be more appropriate. Always check the applicable product specification.