Products Description of Fire Rated Duct

Fire Rated Duct is a key safety component in building HVAC systems, designed to prevent the spread of fire. Its core function is to maintain structural integrity during a fire, block the spread of flames and high-temperature smoke through ventilation ducts, and thus gain time for personnel evacuation and fire rescue operations.

Core Functions and Design Principles

Fire Resistance Integrity
Fire-rated ducts must remain structurally stable at high temperatures (over 800°C¹⁸) to prevent flame penetration. The dynamic temperature distribution of internal airflow directly affects fire resistance, requiring CFD simulation for optimized design⁸.

Smoke and Toxic Gas Blocking
Fire-resistant materials (e.g., rock wool) wrapped around ducts inhibit toxic smoke spread, reducing inhalation casualties¹.

Structural Support and Heat Transfer Control
Special insulation layers (such as UL 94-certified flame-retardant EPDM gaskets⁹) reduce heat transfer to avoid igniting surrounding combustibles while maintaining duct mechanical strength.

PIR PID Duct

PIR Insulation Panel

PIR Insulation Duct Foam Panels

Comparison of Fire Rated Ducts

Performance Indicator	Phenolic Duct Board	Polyurethane Duct Board	Glass Wool
Fire Rating	Generally reaches Class A2 (quasi - non - combustible). New bio - based phenolic is more environmentally friendly	Flame - retardant type can reach Class B1, forming a carbonized layer to isolate oxygen during combustion	Class A non - combustible, effectively preventing fire spread
Combustion Performance	When burning, the smoke density rating SDR < 5, with little smoke; Traditional process has free formaldehyde ( < 0.1mg/m³ when up to standard), new bio - based is better	B1 grade does not burn rapidly and violently when encountering fire. When the flame retardant effect weakens under a strong fire source, it can still delay the fire to a certain extent; May release toxic gases during combustion, and risks can be reduced with compliance use	It is non - combustible itself, and no harmful gases or smoke are released during fire
Safety	New bio - based is environmentally friendly, traditional has a small amount of formaldehyde risk	With proper use and good measures, the carbonized layer ensures certain safety; There is a risk of toxic gas release during combustion	Chemically stable, no toxic substances released, safe
Thermal Conductivity	Approximately 0.022 - 0.028W/(m·K)	0.018 - 0.024W/(m·K), excellent thermal insulation	0.035 - 0.045W/(m·K), relatively weak thermal insulation
Mechanical Strength	Has a certain strength, but relatively weaker than polyurethane	Compressive strength 150 - 300kPa, high mechanical strength	Low strength, easy to be damaged
Waterproof Performance	Has a certain waterproof property	High closed - cell rate, low water absorption, good waterproof performance	Relatively strong water absorption, thermal insulation and other properties decline after water absorption
Construction Convenience	Needs cutting and splicing, relatively troublesome	Can be foamed on - site, suitable for complex - shaped substrates, convenient	Needs cutting and fixing, has requirements for construction process