Thanks to its excellent products and quality services, UNT Duct is one of the leading fire rated pir pre-insulated duct manufacturers and suppliers in China. Welcome to buy the high quality and customized products from our factory. We will offer you the best service and fast delivery.

What is Fire Rated PIR Pre-insulated Duct?

Fire Rated PIR Pre-insulated Duct is a factory-engineered HVAC air distribution system where the structural core, thermal insulation, and fire resistance are integrated into a single composite panel. The core is made of Polyisocyanurate (PIR) foam-a thermoset plastic known for its superior fire performance and low smoke emission-sandwiched between two outer layers, typically aluminum foil, coated steel, or other fire-resistant facings.

Unlike traditional sheet metal ducts that require separate external insulation (e.g., fiberglass wrap), this product serves as both the air-conveying conduit and the insulation layer in one assembly.

Key Fire-Related Properties

The "Fire Rated" designation means the duct system has passed rigorous international or regional fire safety standards:

Fire Resistance Class: Typically meets standards like BS 476 Part 6&7, ASTM E84 or GB 8624 (China). Common ratings include Class B-s1, d0 (low flammability, very low smoke, no flaming droplets) or even Class A.

Reaction to Fire: PIR has a limited oxygen index and is self-extinguishing. It chars rather than melts, reducing fire spread.

Smoke Development: Low smoke emission compared to other polymers (e.g., EPS), crucial for life safety in escape routes.

Temperature Endurance: Can withstand service air temperatures from -50°C to +80°C (-58°F to +176°F), with intermittent resistance up to +120°C (248°F).

Advantages of Fire Rated PIR Pre-insulated Duct Over Traditional Ducts

Feature	Traditional Metal Duct + Wrap	Fire Rated PIR Duct
Installation	Two-step (metal + onsite insulation)	One-step, prefabricated
Weight	Heavy	Extremely lightweight (~1/10th of metal)
Thermal bridging	Present at supports & joints	Minimal – continuous insulation
Air leakage	Higher (sheet metal joints)	Very low (tongue-and-groove joints sealed with special adhesive)
Condensation	Risk if vapor barrier damaged	Intact vapor barrier on both sides
Corrosion	Possible at internal welds/edges	Inert aluminum interior
Fire safety	Dependent on separate wrap (easily damaged)	Inherent, robust, tested as system

Fire Rated PIR Pre-insulated Duct is a modern, high-performance alternative to traditional insulated metal ducts. It offers excellent fire resistance, low smoke toxicity, light weight, fast installation, and superior thermal efficiency. However, it must be designed and installed strictly according to manufacturer guidelines and local fire regulations – particularly regarding joint sealing, support spacing, and use in extreme pressure/temperature environments. When correctly applied, it significantly reduces HVAC system energy losses and installation time without compromising fire safety.