Thickness of Fire-Retardant Coating for Metal Cable Trays

Metal cable trays typically have a base thickness of 1.5–3 mm, with fire-retardant coatings applied according to product specifications, often ranging from 0.7 mm for specialized fire-protective layers.Metal Tray ThicknessThe sheet metal thickness of cable trays generally ranges from 1.5 mm to 3 mm for side plates and base plates, depending on the load and structural requirements. Heavier components, such as brackets and supports, may exceed 3 mm to ensure mechanical strength and stability . The metal is often galvanized for corrosion resistance, with hot-dip galvanization providing a zinc layer of at least 45 µm for standard trays and ≥55 µm for heavier components . Electro-galvanized trays have thinner coatings, typically ≥12 µm, suitable for indoor, dry environments .Fire-Retardant Coating ThicknessFire-retardant coatings, such as FLAMMOTECT-A or DG-CR 0.7, are applied to cable trays to prevent flame propagation and maintain cable functionality during a fire . The thickness of these coatings varies by product and application, but DG-CR 0.7 indicates a nominal coating thickness of 0.7 mm, forming a robust protective layer around the cables and tray. These coatings are designed to resist environmental factors like UV radiation, moisture, and chemicals, and are suitable for both indoor and outdoor installations .Firestopping ConsiderationsWhen cable trays penetrate walls or slabs, additional firestopping measures are required. Firestop packs, boards, or mastic are used to seal gaps, with packing thicknesses typically not less than 24 cm for large openings, ensuring a continuous fire barrier around the tray . The combination of metal tray thickness, galvanization, and fire-retardant coating ensures compliance with safety standards and reliable performance in fire scenarios.SummaryTray metal thickness: 1.5–3 mm (side/base plates), heavier supports >3 mmZinc coating (galvanized): 45–55 µm for hot-dip, ≥12 µm for electro-galvanizedFire-retardant coating: ~0.7 mm for specialized products like DG-CR 0.7Firestopping at penetrations: minimum 24 cm packing thickness for large openings This combination of metal thickness, protective coating, and firestopping ensures both structural integrity and fire safety for cable tray installations in industrial, commercial, and critical infrastructure environments .