Pre Insulated Ducts
UL181 Certified
WT provides full-service solutions for the design and production of pre-insulated duct systems and panels, certified to UL 181 Class 1 Air Duct standards for superior fire resistance. Its pre-insulated metal ductwork features a closed-cell phenolic foam core that minimizes flame spread, resists microbial growth, and prevents moisture penetration, ensuring clean airflow and long-term insulation integrity.
The phenolic duct system achieves industry-leading thermal performance with high R-values, delivering exceptional energy efficiency while meeting strict energy codes. pre insulated ducts are up to 72% lighter than traditional sheet metal, enabling faster installation, reduced structural loads, and significant weight savings. Designed for both indoor and outdoor use, it resists UV exposure, weather extremes, and chemical degradation.
WT’s duct solutions, including the Pro R Indoor, are engineered to achieve SMACNA Phenolic Duct Construction Standards, with low air leakage (Class 1–3 leakage ratings) that optimize HVAC performance and reduce runtime, ensuring significant energy savings. Pre Insulated Ducts Systems combine durability, safety, and efficiency, making them ideal for critical applications that demand high performance and reliability.
Pre Insulated Ducts Highlights
- The first rigid phenolic ductwork system in the world to be UL 181 listed as a Class 1 Air Duct, offering high performance and reliability.
- A fiber-free, rigid insulation core minimizes the risk of loose fibers entering the airstream through the duct systems, ensuring clean and safe air distribution.
- Low air leakage – easily achieves SMACNA Phenolic Duct Construction Standards, providing efficient and effective airflow management.
- Weighs up to 72% less than metal ductwork constructed from sheet metal and insulated with mineral fiber insulation, offering significant weight savings and ease of installation.
Advanced and Innovative Pre–insulated HVAC Ductwork System
An advanced and premium performance Pre Insulated Ducts system which offers benefits such as reduced installation time, low weight, and more!
| Category | Specification | Technical Indicators |
| Standard thickness | 20mm(0.7874 inches), 25mm(0.9843 inches), 30mm(1.1811 inches) (customizable) | Thermal conductivity: 0.019-0.02W/(m/k) |
| Length/width | 2000mm x 1200mm(78.7402 inches x 47.2441 inches), 3000mm x 1200mm(118.1102 inches x 47.2441 inches), 4000mm × 1200mm(157.4803 inches x 47.2441inches) (customizable) | Water absorption: ≤3.7% |
| Foam thickness | 0.025mm(0.0009843 inches), 0.04mm(0.0015748 inches), 0.06mm(0.0023622 inches), 0.08mm(0.0031496 inches) | Fire resistance: B1 level flame retardant |
| Settlement density | 50-65 Kg/m³ | Tensile strength: ≥1.1MPa |
| Temperature resistance | -150℃~150℃(-300℉~300℉) | Thermal resistance: 0.86m2K/W |
| Compressive strength | ≥0.18MPa | Dimensional stability: ≤2% (70±2℃, 48h) |
| Water absorption | ≤1.2% | Impact rigidity: >1.5h |
| Combustibility | ≤9, No spontaneous combustion, No smoke toxicity | Fire rating: A |
| Thermal conductivity | ≥45 | |
| Daily evaporation | ≤0.5mg/L |
What Are The Main Advantages Of Wt Ductwork Over Insulated Sheet Metal?
- Approximately 80% lighter weight than insulated sheet metal
- Installation speed approximately three times faster
- Thickness integrity of insulation maintained across all ductwork systems
- Space saving and time saving with single-fix installation
- Can provide highly airtight ductwork – ensuring reduced air leakage and lower running costs
- Reduced installed and life cycle costs
- Clean air capability – airflow contacts only aluminum surfaces, with no loose fibers
- Reduced risk of moisture penetration compromising insulation performance
UL 181 Listed Safety
Some phenolic duct systems have undergone extensive UL testing to achieve a UL 181 Listed status. Starting with Kingspan KoolDuct in 2004, these tests cover multiple safety and durability aspects, including structural testing, pressure testing, mold and bacteria resistance, static load, and flame and smoke spread. This certification guarantees high standards of safety and reliability.
Weight Savings
Pre insulated ducts made from rigid phenolic foam can deliver significant weight savings for your project. Indoor systems, in particular, offer the highest savings, with rectangular, round, and flat oval designs achieving over a 70% reduction in weight compared with metal duct wrapped in fiberglass.
High R-Values
Phenolic foam has excellent thermal performance, offering some of the best R-values per inch of insulation on the market. This superior insulating efficiency allows thinner insulation to achieve the desired R-value. As energy codes demand higher insulation levels, phenolic duct systems meet and exceed today’s requirements while preparing for future regulations.
Space Saving
Phenolic ductwork is pre-insulated, which means pre insulated ducts do not require additional insulation wrapping. This feature minimizes space requirements and allows ducts to be installed in tighter spaces, including flush to ceilings and walls. Fewer hangers may also be needed, depending on the size of the ductwork systems, further contributing to space saving benefits.
Lower Air Leakage
Phenolic ductwork assembled and installed according to SMACNA Phenolic Duct Construction Standards easily achieves leakage ratings between SMACNA Class 1 and Class 3. This lower air leakage reduces HVAC equipment runtime over the life of the pre-insulated ducts system, resulting in significant energy savings, improved indoor air quality from phenolic’s smooth aluminum interior, and enhanced comfort levels.
Phenolic is a high-performance alternative duct material that offers HVAC contractors a 2-in-1 solution—combining ductwork and insulation into a single system. Phenolic duct systems provide superior thermal performance, reduce air leakage, and eliminate the need for additional insulation. Suitable for both interior and exterior applications, these systems are the ideal choice for modern HVAC installations, delivering reliability, energy efficiency, and long-term cost savings.
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Address： No. 5, Outer Ring North Road, Huangtang Industrial Concentration Zone, Xuxiake Town, Jiangyin City, Jiangsu Province
Email: sales@wtinsulation.com