Phenolic Ductwork
Thermatuff® Phenolic Pre-Insulated Ductwork
Thermatuff® is designed for commercial HVAC applications that require insulated ductwork with a smooth, fiber-free interior surface. Available in R-6, R-8, and R-12 insulation values, Thermatuff® combines the duct and insulation into one pre-insulated assembly, reducing the need for separate duct liner or field-applied insulation. Its durable aluminum facing provides a clean interior surface while sealed panel seams and engineered connection methods support low-leakage air distribution.
Thermatuff® ductwork can be fabricated in long sections to reduce joints, hangers, and field assembly. Its lightweight construction can make completed sections easier to transport, lift, and position than comparable insulated sheet metal assemblies. For contractors, that means fewer installation steps, less trade coordination, and a practical way to provide high-performance insulated ductwork for indoor commercial HVAC applications.
Thermatuff® Pre-Insulated Ductwork vs. Traditional Insulated Ductwork
Fiber Free Insulation
Thermatuff® uses closed-cell phenolic insulation with a smooth, fiber-free aluminum interior surface. Unlike fibrous duct liner, the insulation core is contained behind a zero-perforation facing, providing a clean surface for the airstream and supporting improved air and vapor control when the completed system is properly sealed. Thermatuff® is available in R-6, R-8, and R-12 insulation values for a wide range of commercial HVAC applications.
Reduced Space Requirements
Because Thermatuff® combines duct construction and insulation into one pre-insulated assembly, contractors do not need to allow for a separate layer of external insulation around the installed duct. This can reduce the overall space required for insulated ductwork and provide greater flexibility above ceilings, around structural members, and in other congested areas.
Low Air Leakage
Thermatuff® systems easily achieve a SMACNA Class 3 leakage rating when fabricated and installed by Thermaduct® or SMACNA Phenolic Duct Construction Standard requirements. This phenolic system can reduce energy costs and can solve leakage rates commonly associated with longer duct runs.
Weight Savings
Thermatuff® pre-insulated ductwork is lighter than comparable insulated sheet metal assemblies. The reduced weight can make fabricated sections easier to transport, lift, position, and install while also reducing loads placed on hangers and supporting structures. For field crews, that can mean more manageable duct sections and a more efficient installation process.
Fire and Smoke Performance
Thermatuff® phenolic insulation meets ASTM E84 requirements with flame-spread and smoke-developed ratings of 25/50. This provides the documented fire and smoke performance required for commercial HVAC insulation while maintaining the high thermal performance associated with phenolic materials.
Interior Phenolic Healthcare Ductwork
Focused on Air Quality - Smooth and Fiber-Free Interior
Thermatuff® pre-insulated ductwork provides a smooth aluminum interior surface without exposed fibrous insulation in the airstream. For commercial HVAC applications where cleanliness, maintenance, and indoor air quality are important considerations, the zero-perforation facing keeps the closed-cell phenolic insulation contained behind a durable surface.
Compared with traditional fibrous duct liner, the smooth interior can also reduce surface roughness and provide a more consistent path for airflow. Combined with low-leakage construction and lightweight pre-insulated assemblies, Thermatuff® offers contractors and engineers a practical alternative for schools, healthcare facilities, offices, and other projects requiring insulated ductwork with a clean interior surface.
Additional Information
Low Leakage Insulated Ductwork - Helping to Reduce Heating, Cooling and Fan Energy
Thermatuff® pre-insulated duct systems use sealed panel seams and engineered connection methods designed to support low-leakage construction. When properly fabricated and installed, Thermatuff® ductwork can achieve SMACNA Class 3 leakage performance, helping keep conditioned air inside the duct system and reducing the corrective sealing work that may be required in the field.
The accompanying graph shows the maximum allowable air leakage for each SMACNA leakage class across operating pressures from 0.1 to 4 in. w.g. Lower duct leakage can reduce unnecessary fan operation and limit the heating or cooling energy lost before conditioned air reaches the occupied space.
For contractors, engineers, and building owners, Thermatuff® provides insulated ductwork that combines dependable thermal performance with low-leakage construction for efficient commercial HVAC air distribution.
Moisture-Resistant Closed-Cell Phenolic Insulation with Zero-Perforation Facings for Improved Vapor Control
Thermatuff® features a phenolic insulation core with greater than 90% closed-cell content, helping limit moisture absorption within the panel. Unlike insulation panels manufactured with perforated facings, Thermatuff® uses factory-applied aluminum facings with zero perforations, providing a continuous surface over the insulation core on both sides of the panel.
The non-perforated facings help keep the insulation fully encapsulated and provide a strong foundation for air and vapor control. When panel seams, joints, edges, and penetrations are properly sealed with approved Thermaduct® closure materials, the completed assembly helps protect the insulation from moisture migration throughout the life of the duct system.
Unmatched Thermal Performance
Thermatuff® phenolic panels provide high insulating performance in a relatively thin, rigid panel construction. Available in R-6, R-8, and R-12 values, Thermatuff® allows contractors and engineers to meet a wide range of commercial HVAC insulation requirements without adding a separate layer of external insulation to the completed duct system.
This compact construction can be especially valuable above ceilings, around structural members, and in other congested areas where space for insulated ductwork is limited. Because the insulation is incorporated directly into the duct system, or mechanically retained within sheet metal ductwork, Thermatuff® can help reduce the overall installed profile and simplify coordination with piping, electrical systems, ceilings, and other building components.
Lightweight, Pre-Insulated Construction to Help Reduce Handling and Installation Labor
Thermatuff® pre-insulated ductwork is lighter than comparable insulated sheet metal assemblies, making fabricated sections easier to transport, stage, lift, position, and install. Because the insulation is built directly into the duct system, contractors can also eliminate the separate field step of wrapping or insulating the duct after installation.
The reduced weight and one-pass construction can help crews handle larger sections, reduce material handling, and complete more insulated ductwork with fewer installation steps. Support spacing and installation requirements are determined by the Thermaduct® construction tables for the specific duct size, pressure, and application.
Resistant to Fire and Smoke
Thermatuff® phenolic panels have been tested in accordance with ASTM E84 for surface-burning characteristics, achieving a flame spread index of 25 or less and a smoke-developed index of 50 or less. These results meet the 25/50 surface-burning criteria referenced by NFPA 90A and NFPA 90B for applicable materials used in air-distribution systems.
Insulated Ductwork Built to SMACNA Phenolic Standards
Thermatuff® panels are engineered for the fabrication of commercial pre-insulated ductwork in accordance with the SMACNA Phenolic Duct Construction Standards, 2015 Edition. These standards provide established requirements for the fabrication, reinforcement, joint construction, sealing, and installation of phenolic insulated duct systems.
Completed insulated ductwork must be fabricated and installed for the specified duct size, pressure class, insulation value, and application. Thermatuff panels are available in multiple thicknesses and R-values, allowing contractors and engineers to select an insulated duct system based on project specifications and locally adopted energy-code requirements. Our team at Delta Air Systems can help guide you in this selection to better develop
Fiber-Free Interior for Commercial Insulated Ductwork
Thermatuff® insulated ductwork provides a smooth, sealed aluminum interior surface with no exposed fibrous insulation in the airstream. This helps reduce the risk of loose insulation fibers entering the air-distribution system while providing an interior surface suitable for commercial HVAC applications.
The closed-cell phenolic insulation core is non-fibrous, odorless and non-tainting. Because the insulation is enclosed behind the aluminum facing, the completed pre-insulated duct system provides a clean, durable air surface for applications where interior duct cleanliness and material containment are important considerations.