Double-layer fireproof cable trays should be installed using approved materials, proper layout, and firestopping measures to ensure safety, reliability, and compliance with technical standards.

Planning and Layout

Proper planning is essential for double-layer cable tray systems. The trays should follow the shortest and straightest path to minimize cable loss and simplify maintenance, while avoiding unnecessary crossings with other pipelines or building structures ( ). Power and signal cables must be segregated using separate trays to reduce electromagnetic interference ( ). Review approved shop drawings to confirm tray layout, length, and positioning before installation ( ).

Material Selection

• Indoor environments: Painted steel or galvanized steel trays are recommended.
• Outdoor or high-humidity areas: Hot-dip galvanized steel, stainless steel, aluminum alloy, or fiberglass-reinforced plastic trays provide corrosion resistance ( ).
• Fireproofing: Use fire-resistant coatings or tapes such as FLAMMOTECT-A or DG-CR 0.7 to protect cables from flame propagation and environmental damage ( ). Tray width and thickness should be selected based on the number and weight of cables, ensuring mechanical strength to prevent deformation under full load ( ).

Installation Requirements

• Supports and alignment: Trays must be level, plumb, and securely mounted. Horizontal deviation should not exceed 2 mm per meter, and vertical deviation should not exceed 3 mm per meter ( ).
• Storage and handling: Store trays horizontally on flat surfaces with timber supports at 1-meter intervals, protected from moisture and sunlight ( ).
• Double-layer configuration: Ensure proper spacing between layers to allow heat dissipation and maintenance access. Use appropriate fittings and accessories to secure the upper and lower layers.

Firestopping and Penetrations

When cable trays pass through walls, slabs, or shafts, firestopping is critical:

• Seal openings with fire-rated boards, firestop packs, mastic, or mineral wool.
• Maintain a gap area ≤1 cm² between firestop packs and cables, with packing thickness ≥24 cm ( ).
• For large openings, install a fire-resistant backing plate before sealing.
• At slab penetrations, provide 20–30 mm of firestopping and a fire-support plate at the top.
• Ensure all gaps are sealed tightly, both internally and externally, and cover plates are square and evenly painted ( ).

Environmental and Safety Considerations

• Ensure trays and fireproofing materials are resistant to UV radiation, moisture, chemicals, and temperature variations ( ).
• Follow local electrical codes and safety regulations in Paraguay, and coordinate with building and fire safety authorities.
• Conduct inspections for material compliance, damage, and proper installation before energizing the system ( ).

Maintenance

• Regularly inspect trays for corrosion, mechanical damage, and fireproofing integrity.
• Maintain clear access for cable replacement or upgrades.
• Document all inspections and maintenance activities to ensure long-term reliability. By following these guidelines, double-layer fireproof cable trays in Paraguay can be installed safely, ensuring fire protection, structural integrity, and compliance with international standards.