Flame Resistant (FR) clothing is designed to protect workers from flash fire, arc flash, and heat hazards-but its performance over time depends heavily on how it is laundered. Industrial washing subjects garments to far more severe conditions than domestic laundering, and incorrect processes can compromise protection long before the end of the garments expected life. For this reason, the maximum allowable number of wash cycles is specified on garment labels.
Choose FR Wisely: Fabric Build and Chemistry
FR fabrics are broadly classified into two categories. Inherent FR fabrics and treated FR fabrics. Flame-resistant (FR) performance depends fundamentally on how flame resistance is achieved either through inherent fibre chemistry or chemical treatment. Understanding this distinction is critical for safety, durability, and lifecycle cost.
Inherent FR fabrics derive flame resistance from the molecular structure of the fibre itself. The polymer backbone is non-flammable, meaning protection is permanent and cannot be removed by wear, laundering, or chemical exposure. When exposed to intense heat or flame, aramid fibres undergo a controlled thermal response in which the fibre structure expands (swell) and increases in bulk. This expansion promotes the formation of a stable, insulating char layer that limits heat transfer from the flame to the skin. The resulting barrier remains flexible during thermal exposure and only stiffens upon cooling, allowing the wearer valuable additional time to move away from the hazard and reduce injury risk. Common examples include aramids, mod acrylic fibres, and PBI blends.
Treated FR fabrics are typically made from cotton or cotton-blend textiles like cotton-polyester that rely on applied flame-retardant chemistries bonded to or embedded within the fabric. Flame resistance is activated through a heat-driven chemical reaction that suppresses combustion. While effective when properly maintained, performance is dependent on chemical integrity, which can be degraded by aggressive laundering, oxidizing agents, or workplace contaminants. Common examples like cotton, Cotton / polyester, cotton / viscose.
While both fabric types are designed to meet recognized safety standards, inherent FR fabrics generally offer higher durability under harsh conditions, whereas treated FR fabrics rely more heavily on correct laundering and maintenance to retain their protective performance.
Selecting the correct FR technology ensures consistent protection, regulatory compliance, and predictable service life, especially in high-risk or high-laundering environments. Fabric choice directly affects worker safety, garment reliability, and long-term cost control.
Industrial Laundering: A Critical Factor in FR Safety
FR garments are personal protective equipment (PPE), not ordinary work wear. Their protective function relies on clean fabric surfaces and intact flame-resistant chemistry. While FR properties do not “wash off,” incorrect industrial laundering can chemically damage the FR finish or leave flammable contaminants on the garment surface. These contaminants can ignite during a fire or arc event, preventing the fabric from self-extinguishing and increasing heat transfer to the wearer.
Oxidizing agents such as chlorine bleach or peroxide can degrade flame-retardant finishes. Fabric softeners, starch, soap residues, lint, oils, and grease can become thermally fixed to the fabric during high-temperature drying, creating a flammable surface layer. Additionally, shrinkage or seam degradation can expose skin and compromise compliance with heat and flame protection standards such as EN ISO 11612 or NFPA 2112.
Inherent FR fabrics retain flame resistance at the polymer level, so performance is not affected by laundering or typical workplace chemicals. Treated FR fabrics depend on applied chemistries that can degrade under oxidizing conditions such as chlorine bleach, peroxide systems, hard water, or chemical exposure, leading to rapid loss of protection. This makes inherent FR garments more stable, reliable, and longer-lasting over repeated industrial wash cycles.
Factors Affecting FR Fabric
| Factors | The Danger | The Solution |
| Bleach | Breaks down FR molecular bonds | Use mild liquid detergent only (Avoid bleach detergents) |
| Fabric Softener | Coats fibres in flammable wax | Use dryer balls for softness |
| Regular Laundry (Mixed Loads) | Contaminates material with flammable lint | Wash FR loads separately |
| Hard Water | Leaves flammable mineral deposits | Use water softeners |
| Hot Water (>140°F / 60°C) | Damage fabric in repeated washing (use only when Sanitizes, removes tough grease/oil stains) | Wash warm (120–140°F) |
| Starch / DEET | Adds fuel to the fabric | Avoid completely |
Maintaining FR Performance & ISO 15797:2017 Standards
ISO 15797:2017 simulates severe industrial laundry conditions, including wash temperatures of 75–85 °C, high mechanical action, alkaline detergents, and drying temperatures up to 155 °C, these conditions evaluate fabric degradation, dimensional stability, and retention of protective performance over repeated cycles.
To preserve FR performance over time, garments must be laundered using controlled industrial processes. This includes washing FR clothing separately, using mild, non-bleach, liquid detergents, avoiding fabric softeners and starch, and ensuring thorough removal of oil and grease contaminants. Garments intended for industrial use should be designed and tested to ISO 15797 and regularly inspected for damage, shrinkage, or improper repairs. Maintaining FR protection is a shared responsibility between the manufacturer, employer, industrial laundry, and wearer.
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