What materials are used for the fire-retardant coating on cable trays

Fire-retardant coatings for cable trays typically use water-based ablative, intumescent, or latex-based formulations containing heat-absorbing fillers and reactive compounds to prevent flame spread.

Common Types of Fire-Retardant Coatings

1. Water-Based Ablative Coatings These coatings, such as SikaSeal®-641, are applied directly to cable trays and grouped cables. They form a protective layer that chars and insulates the cables under fire exposure. The main materials include water as a carrier, intumescent additives, and inorganic fillers that help absorb heat and slow flame propagation. The effectiveness depends on the applied film thickness, typically around 1.6 mm dry film thickness for cable trays, and they are easy to clean and environmentally friendly . 2. Intumescent Coatings Intumescent coatings, like ALTIC 007, are reactive paints that expand when exposed to heat, forming an insulating char layer. Key materials include polymers that swell under heat, halogen-free flame retardants, and fillers that enhance thermal insulation. These coatings are water-based, flexible, and eco-friendly, providing up to 4 hours of circuit integrity. They also resist water, oil, UV radiation, and chemicals, making them suitable for indoor and outdoor applications . 3. Latex-Based Coatings with Endothermic Fillers Products such as MCC cable coating use latex as a binder combined with endothermic fillers that absorb heat and release water to limit flame spread. These coatings adhere well to various cable jacketing materials, provide high coverage, and are easy to clean with water. The fillers act as a heat sink, reducing the temperature and slowing fire propagation along the cable tray .

Functional Additives and Properties

• Intumescent agents: Expand under heat to form a protective char.
• Endothermic fillers: Absorb heat and release water to reduce flame intensity.
• Polymers and binders: Provide adhesion and flexibility.
• Inorganic fillers: Enhance thermal insulation and structural integrity.
• Halogen-free compounds: Reduce toxic gas release during fire.

Application Considerations

• Coating performance is thickness-dependent; proper film thickness ensures fire protection.
• Water-based coatings are environmentally friendly and easy to clean.
• Intumescent coatings are often factory-applied for consistent quality, while wraps or multilayer systems may be used for retrofits.
• Coatings can be designed to withstand UV, moisture, oil, and chemical exposure, ensuring durability in industrial and outdoor environments . In summary, fire-retardant coatings for cable trays rely on water-based, intumescent, or latex formulations with heat-absorbing fillers, polymers, and reactive additives to prevent flame spread, maintain circuit integrity, and provide environmental resistance.