Regarding fire-resistant cable trays

It’s just that flame-retardant fireproof material is applied outside the cable tray; there’s nothing special about it

Of course, there are specialized fire-resistant cable trays, which come in types with an inner fire-resistant layer and an outer fire-resistant layer.

Galvanizing is divided into hot-dip galvanizing and cold galvanizing: Hot-dip galvanizing involves reacting molten metal with the iron substrate to form an alloy layer, thereby bonding the substrate and the coating together. Hot-dip galvanizing offers advantages such as a uniform coating, strong adhesion, and a long service life. Cold galvanizing is the same as electro-galvanizing, and its corrosion resistance is much lower than that of hot galvanizing. The price is also relatively low. Differences in galvanized finished products: The surface of hot-dip galvanizing is not as smooth and shiny as that of cold galvanizing, but the thickness of the zinc layer in hot-dip galvanizing is several dozen times that of cold galvanizing. Its corrosion resistance is also dozens of times that of electro-galvanizing. Uses and classifications of fire-resistant and flame-retardant cable trays: Flame-retardant and fire-resistant cable trays are suitable for the installation of power cables with voltages below 10 KV, as well as control cables and lighting wiring, in both indoor and outdoor cable trenches and tunnels. Flame-retardant cable trays are divided into internally flame-retardant, externally flame-retardant, and fully flame-retardant types. The internal flame-retardant type features flame-retardant materials coated on or embedded in the inner surface of trough or tray cable trays, and is commonly used for flame-retardant partitions; that is, when a cable catches fire, the flame-retardant layer helps to limit the extent to which the fire spreads along the cable. The externally flame-retardant type features a layer of flame-retardant material applied to its outer surface to prevent external flames from compromising the mechanical strength of the steel cable tray, making it suitable for areas prone to frequent fires. The fully flame-retardant type features flame-retardant materials coated on the inner and outer surfaces or flame-retardant panels embedded therein, which not only preserves the mechanical strength of the steel cable tray but also limits the spread of fire from ignited cables. Process materials, structure, and performance of flame-retardant and fire-resistant cable trays: The steel framework is primarily made from high-quality cold-rolled sheets through mechanical processing, offering high load-bearing capacity and a long service life. The cross-section of the steel frame is neat, free of burrs and sharp corners, with the grooves being smooth and flat without any sharp protrusions. ①After processing and shaping, the cross-sectional shape is uniform, free from defects such as bending, warping, cracks, or edges. ②Fireproof boards are made from siliceous materials and calcareous materials as the main raw materials, mixed with a certain proportion of fiber materials, lightweight aggregates, binders, and chemical additives, and then produced using advanced autoclaving techniques. ③Fireproof coating is an efficient protective product for steel structures. It is formulated using high-performance synthetic resins as the film-forming substance, along with flame retardants, foaming agents, carbonizing agents, and high-temperature fire-resistant materials. Under high-temperature conditions, the coating undergoes continuous foaming and expansion, forming a flexible, sponge-like carbonized insulation layer that prevents the steel structure it supports from softening or deforming rapidly due to the effects of high temperatures and flames, thus avoiding a sharp decline in its strength. The applied fire-resistant coating layer should be even, smooth, with no noticeable color differences. Powder coating, also known as electrostatic powder spraying, involves using an electrostatic generator to charge plastic powder, which then adheres to the surface of iron sheets. Subsequent baking at 180–220°C causes the powder to melt and stick to the metal surface. Products coated in this way are often used for indoor cabinets, with a paint finish that is either smooth or matte. Spray painting powders mainly include acrylic powder, polyester powder, etc.