Fireproof sealing only applies to the inside of the cable tray

Fireproof sealing is not limited to the inside of the cable tray; it also applies to penetrations, surrounding structures, and external surfaces to ensure complete fire containment.Internal and External FireproofingWhile the interior of a cable tray may be treated with fireproof coatings or filled with fire-resistant materials, fireproofing extends beyond the tray itself. Openings where cable trays pass through walls, floors, or slabs must be sealed with firestopping materials such as firestop packs, intumescent pillows, or fire-resistant mineral wool to prevent fire and smoke spread . All gaps inside and around metal trunking or trays must be tightly sealed both internally and externally .Fireproof Coatings and Tray AcceptanceFireproof cable trays often have specialized coatings that enhance resistance to heat, corrosion, and wear. These coatings are applied to the tray surfaces and are critical for compliance with fire safety standards. Proper inspection ensures that the coating is uniform, adheres securely, and meets the required fireproof grade . This demonstrates that fireproofing is not confined to the tray interior but includes the external surfaces as well.Penetration SealingFor cable trays passing through walls or floors, fireproof pillows or cable boxes are used to seal the penetration. Products like AF BAGS or System Cable Tube provide fire resistance up to EI 120–240 and are designed to be installed inside the penetration, creating a complete barrier around the cables . These systems ensure that fire cannot propagate through openings, highlighting the importance of external sealing.Maintenance and InspectionFireproof sealing requires periodic inspection to check for cracks, corrosion, or coating degradation. Both internal and external fireproofing measures must be maintained to ensure long-term effectiveness . This includes verifying that firestop materials remain intact and that tray coatings continue to meet fire resistance standards. Conclusion: Fireproof sealing for cable trays is a comprehensive process that includes internal tray protection, external coatings, and sealing of penetrations. Limiting fireproofing to the inside of the tray alone is insufficient for fire safety compliance and effective containment .