Due to their differing fire-resistant structures and materials, different types of fire-resistant cable trays have significant differences in fire protection duration. The core reason lies in the composition of the fireproofing layer. Currently, the mainstream fire-resistant coated plate cable trays, composite fire-resistant cable trays, and inorganic fire-resistant cable trays each focus on their duration. Fire-resistant coated plate cable trays rely on thin or thick coatings applied to the surface of a steel base, typically providing a duration of 30-90 minutes. Composite fire-resistant cable trays utilize a steel base encased in fireproof panels and fire-resistant seals, achieving a duration of 60-120 minutes. Inorganic fire-resistant cable trays are constructed from pressed inorganic, non-combustible materials such as magnesium oxide and calcium silicate, offering a duration of 90-180 minutes.
The core reasons for these differences in duration can be attributed to two factors. First, the fire protection mechanisms differ: Fire-resistant coated cable trays rely on the expansion of the coating or physical insulation, and fail if the coating burns through. Composite fire-resistant cable trays use a multi-layered structure to block heat, and their sealing properties affect the upper limit of fire protection. Inorganic fire-resistant cable trays are inherently non-combustible, eliminating the risk of coating failure. Second, the materials have different heat resistance limits: thin coatings have a heat resistance of ≤600°C, while thicker coatings can reach 1000°C, while inorganic substrates generally have a heat resistance of ≥1200°C. This difference in heat resistance directly determines the fire protection rating.
Selection requires precise matching based on fire protection requirements. For non-fire protection cables in ordinary office buildings and residences, a 30-60 minute fire protection period is sufficient, so thin fire-resistant coated cable trays can be selected. Fire protection cables in shopping malls and hospitals require a 60-120 minute fire protection period, so thick fire-resistant coated cable trays or composite fire protection cable trays are recommended. For high-risk locations such as chemical workshops and data centers, where a fire protection period of more than 120 minutes is required, inorganic fire-resistant cable trays must be selected to meet the high fire resistance requirements.