Flame-resistant (FR) clothing is a critical component of personal protective equipment (PPE) for workers in industries such as oil and gas, electrical utilities, welding, and chemical processing. However, improper laundering can significantly degrade its protective properties. Understanding how washing affects flame resistance is essential for maintaining both safety and garment longevity.
The primary function of FR clothing is to self-extinguish when exposed to flames or intense heat, minimizing burn injuries. This performance relies on either the fabric's inherent fiber chemistry (e.g., Nomex, Kevlar) or a chemical flame-retardant treatment applied to the fabric (e.g., cotton treated with Proban or Pyrovatex). Both types are vulnerable to common washing mistakes.
Key factors that affect FR properties during laundering include:
1. Contamination by Flammable Residues: This is the most serious threat. When FR clothing is washed with non-FR fabrics, lint from polyester, nylon, or cotton blends can transfer and stick. Additionally, oils, greases, solvents, or waxes from the work environment can remain embedded if not properly removed. These contaminants are highly flammable and can ignite, causing the FR fabric to burn and melt against the skin. Always wash FR items separately and pre-treat heavy oil or grease stains with approved products.
2. Use of Improper Detergents and Additives: Standard household detergents often contain non-FR fabric softeners, bleaches, or optical brighteners. Fabric softeners coat fibers with a waxy, flammable film that can ignite and reduce breathability. Chlorine bleach damages both treated and inherent FR fibers, causing chemical degradation and loss of strength or flame resistance. Optical brighteners (often listed as "fluorescent whitening agents") can also reduce the effectiveness of flame retardant treatments. Use only non-ionic detergents labeled "safe for FR clothing" and avoid any additives.
3. Accumulation of Mineral Deposits (Hard Water): Hard water contains calcium and magnesium ions. Over time, repeated washing in hard water without proper water softeners can leave mineral deposits on the fabric. These deposits can act as a solid fuel source, causing the fabric to burn more readily. Periodic treatment with a chelating agent (like Calgon) or a specialized FR detergent can prevent this.
4. Mechanical Wear and Tear: The washing process itself—agitation, spinning, and drying at high heat—gradually wears down fibers. For inherently FR fabrics, this mechanical damage leads to pilling, thinning, and reduced thermal protection. For chemically treated fabrics, the flame-retardant chemical bonds can be physically abraded away. Always follow the manufacturer's care label: washing in gentle cycles and tumble drying on low heat extends garment life. Avoid overloading the machine to ensure thorough rinsing.
5. Improper Drying and Ironing: Drying at excessively high temperatures can shrink the garment and degrade fibers. Ironing at too high a heat can melt chemical finishes or weaken inherent fibers. Furthermore, starch or other stiffening agents used during ironing can create a flammable coating.
To ensure FR clothing remains effective, establish a strict care routine: wash separately, use mild FR-specific detergent, avoid fabric softener and bleach, dry on low heat, and inspect the garment regularly for damage. If a garment becomes stained with oil, heavily worn, or loses its shape, discard and replace it. Proper laundering is not just about cleanliness—it is an act of safety.