COT-330-FR is the heavy-duty version of our bestselling 100% cotton FR twill — engineered for welding, shipbuilding, steel fabrication, and metallurgy applications where fabric must withstand greater thermal exposure and mechanical abrasion than standard 300gsm FR grades can deliver.
The 330 GSM weight provides a measurable thermal barrier advantage over lighter FR fabrics. In EN ISO 11611 welding tests, the additional 30gsm reduces backside temperature rise during molten metal spatter exposure — a critical safety margin for professional welders working in confined spaces or overhead positions.
The Twill 3/1 weave at this weight creates a dense, tight fabric structure with excellent spark and spatter shedding. The heavier yarn count (Ne 12 × Ne 10) delivers tensile strength exceeding 1200N warp and tear strength above 30N — approximately 20% higher than the 300gsm grade, translating to measurably longer garment life in heavy industrial environments.
FR efficacy retained after 50+ industrial washes (ISO 15797)
Afterflame Time
≤2 seconds (EN ISO 15025 / GB/T 14644)
Afterglow Time
≤2 seconds
Char Length
≤100 mm
Shrinkage
≤3% after 50 washes (ISO 6330)
Colorfastness to Washing
Grade 4 (ISO 105-C06)
Colorfastness to Light
Grade 4 (ISO 105-B02)
Tensile Strength (Warp)
≥1200 N (ISO 13934-1)
Tear Strength (Weft)
≥30 N (ISO 13937-2)
Abrasion Resistance
≥30,000 Martindale cycles
Finishing
Pre-washed, heat-set, FR treated
Standards & Certifications
Standard
Status
GB 8965.1-2020
✅ Class B — China FR mandatory
EN ISO 11612 (A1, B1)
✅ Heat & flame — EU general industrial
EN ISO 11611 (Class 1 & 2)
✅ Welding — molten metal spatter
NFPA 2112
✅ Flash fire — North America
EN 1149 (AS variant)
✅ Anti-static (when ordered with 1% conductive fiber)
OEKO-TEX Standard 100
✅ Available upon request
330gsm vs. 300gsm — When to Upgrade
Factor
COT-300-FR (300gsm)
COT-330-FR (330gsm)
Fabric weight
300 GSM
330 GSM
Tensile strength
≥1000 N
≥1200 N
Tear strength
≥25 N
≥30 N
Abrasion resistance
≥25,000 cycles
≥30,000 cycles
Thermal barrier
Standard
Enhanced — longer protection window
Best for
General industrial, light welding
Heavy welding, shipbuilding, foundry
Cost per meter
Baseline
+8–12%
For general industrial workwear programs, COT-300-FR is sufficient. For dedicated welding programs, shipyard contracts, and heavy metallurgy environments, COT-330-FR is the correct specification.
Applications
Application
Why This Weight
Heavy welding (structural steel, pipeline, shipbuilding)
330gsm provides additional thermal barrier — critical for overhead welding and confined spaces
Steel fabrication and foundry work
Higher abrasion resistance withstands contact with hot metal edges
Shipyard welding and fitting
Durable through the harshest marine industrial environment
Heavy mining and metallurgy
Tear strength ≥30N withstands snagging on equipment
Forging and heat treatment
Extra weight delays heat penetration during brief contact
Oil & gas — heavy maintenance
Welding + heavy equipment access requires maximum fabric durability
Machine wash 60°C, normal cycle — industrial wash compatible
Bleaching
Do not bleach — chlorine degrades FR treatment
Drying
Tumble dry medium, or hang dry
Ironing
High iron (200°C), steam
Industrial laundry
Compatible — 75°C max, alkaline detergents OK
FAQ
Q: Does the extra 30gsm really make a difference in welding? A: Yes. In EN ISO 11611 testing, 330gsm consistently shows lower backside temperature rise during molten metal spatter exposure compared to 300gsm. For professional welders working production welding 8+ hours daily, this additional thermal barrier is a meaningful safety improvement.
Q: Is this fabric comfortable in hot environments? A: 330gsm is noticeably heavier than standard workwear fabrics. It is designed for safety-critical roles where protection takes priority over comfort. For warm-weather welding with lower hazard exposure, consider COT-300-FR. For extreme heat, the inherent FR modacrylic range (IFR-240-MC) offers better breathability at equivalent protection.
Q: Does this fabric meet EN ISO 11611 Class 2? A: Yes. 330gsm meets the requirements for both Class 1 (lower spatter) and Class 2 (higher spatter) welding protection. Most lighter FR fabrics (245–280gsm) only achieve Class 1 certification.
Q: What is the most common color for shipyard welding programs? A: Navy is the standard for most shipyard contracts. Grey follows for welding supervision and inspection roles. Orange is typically specified only when hi-visibility is also required.
Q: Can I combine FR with anti-static on this weight? A: Yes. Same process as the 300gsm grade — add 1% conductive carbon fiber. Product code COT-330-FR-AS. EN 1149 certified.
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