ASTM D3939 Standard Test Method for Snagging Resistance of Fabrics

Core Test Methodology

1. Principle

2. Sample Preparation

• Specimen size: A circular sample (diameter: ~140 mm) is cut and clamped onto a rotating drum covered with a felt pad.

• Orientation: Test both the warp (lengthwise) and weft (crosswise) directions of the fabric to account for structural differences.

• Preconditioning: Samples are conditioned in standard atmospheric conditions (20±2°C, 65±4% RH) for at least 24 hours to ensure consistent results 7.

3. Test Setup

• Apparatus:

• A mace drum with 12–16 tungsten carbide spikes (31.75 mm diameter, 160±10g mass) that rotate against the fabric specimen.

• A counter to track rotations and a viewing cabinet for visual assessment.

• Procedure:

1. Secure the fabric specimen on the drum with the felt pad.

2. Run the mace for the specified number of cycles (e.g., 100 rotations).

3. After testing, evaluate snagging severity using a 1–5 visual rating scale (5 = no snags, 1 = severe snags) and/or count the number of visible loops 57.

4. Key Parameters

• Snagging resistance: Rated based on the number of yarn loops pulled out and their visibility.

• Visual assessment: Consider factors like color contrast (between snags and fabric), distortion (yarn displacement), and protrusion (loop length) 37.

Technical Requirements

• Test precision: The apparatus must maintain a rotation speed of 60 ± 2 RPM and ensure uniform contact between the mace and fabric.

• Environmental control: Testing should be conducted in standard atmospheric conditions to minimize variability 7.

• Data analysis: Report average values from 5+ specimens per direction, with coefficients of variation ≤5% for valid results 3.

Applications

1. Product Development:

• Optimizing fabric structures (e.g., tighter weaves) to reduce snagging risk.

• Assessing the impact of finishes (e.g., anti-pilling treatments) on snag resistance.

2. Quality Assurance:

• Ensuring compliance with industry standards (e.g., EN 13774 for protective clothing) and customer specifications.

• Detecting manufacturing defects (e.g., weak yarns) in mass-produced textiles.

3. Regulatory Compliance:

• Meeting REACH requirements for durable textile products sold in the EU.

• Certifying fabrics for use in high-performance applications (e.g., outdoor apparel)