Double Wall Spiral Duct – SIDCO Spiral Duct Inc.

HVAC Solutions — Premium Grade

Double Wall Spiral Duct

Three-Layer Insulated Performance

Engineered for superior thermal control, acoustic attenuation, and structural integrity. Our double wall spiral duct system delivers unmatched efficiency for demanding commercial and industrial HVAC environments.

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Layer Construction

90GSM

Zinc Coating

4–36"

Diameter Range

✦ Premium Galvanized Steel

✦ Custom Fabrication Available

✦ Fast & Reliable Shipping

✦ Memphis, TN — 24/7 Support

✦ Industry-Grade Quality

Engineering Detail

Three-Layer Construction

Every section is precision-engineered with three distinct layers working in unison — optimized for thermal insulation, sound dampening, and structural rigidity.

Outer Shell

Solid galvanized or paint-grip steel exterior provides structural integrity, weather resistance, and corrosion protection with 90 GSM zinc coating.

Insulation Core

High-density thermal insulation layer minimizes heat gain and loss, reducing energy consumption and maintaining precise climate control throughout the duct run.

Perforated Inner Liner

Precision-perforated inner metal liner absorbs sound waves generated by airflow and mechanical equipment, significantly reducing operational noise levels.

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Smooth Airflow Core

The clean interior bore ensures laminar airflow with minimal turbulence, maximizing system efficiency and reducing pressure drop across long duct runs.

Performance Benefits

Built for Excellence

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Thermal Insulation

Advanced insulation core maintains system temperatures precisely, slashing energy loss and delivering measurable utility savings across every installation.

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Acoustic Performance

Perforated inner liner captures and dampens airflow noise at the source, creating quieter environments in offices, hospitals, schools, and studios.

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Structural Strength

Spiral-wound construction increases radial stiffness by up to 20% over longitudinal duct of equivalent gauge, eliminating the need for external reinforcement.

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Corrosion Resistance

90 GSM zinc galvanization on steel components delivers long-term corrosion resistance even in high-humidity or chemically active environments.

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Custom Fabrication

Available in multiple insulation thicknesses, diameters, and material grades. Every unit is precision-manufactured to your exact project specifications.

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Low Pressure Drop

Smooth bore interior and tightly locked seams reduce air leakage and turbulence, maintaining optimal pressure levels throughout the system.

Technical Specifications

Specs & Standards

Specification	Detail
Available Gauges	20, 22, 24, 26 gauge
Diameter Range	4″ – 36″ standard
Standard Lengths	5 ft & 10 ft
Zinc Coating	90 GSM
Outer Material	Galvanized / Paint Grip Steel
Inner Liner	Perforated Metal
Insulation Type	Fiberglass / Mineral Wool
Ready to Ship (4–14″)	In Stock
Lead Time (16–22″)	1–2 Business Days
Custom Sizes	Available on Request

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Ready Stock Available

Sizes 4″ through 14″ are in stock and ready to ship same or next business day from our Memphis, TN facility.

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Precision Manufacturing

Produced on automated spiral-forming machinery ensuring consistent seam quality, dimensional accuracy, and repeatable performance.

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SMACNA Compliant

Manufactured in accordance with SMACNA standards for commercial HVAC ductwork systems, ensuring code compliance for all project types.

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Nationwide Shipping

We ship to contractors and distributors across the United States. Large-volume orders welcome — contact us for freight pricing.

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Custom Insulation Thickness

Select from multiple insulation R-values and thicknesses to meet project-specific thermal and acoustic performance requirements.

Where It's Used

Ideal Applications

Commercial HVAC

High-performance insulated ductwork for office complexes, retail centers, and multi-tenant commercial buildings where efficiency and aesthetics matter.

Hospitals & Healthcare

Noise-sensitive critical care environments benefit from superior acoustic performance and clean, hygienic airflow pathways.

Schools & Universities

Quiet classrooms, lecture halls, and auditoriums demand low-noise HVAC — double wall construction delivers exactly that.

Industrial Facilities

Warehouses, manufacturing plants, and processing facilities with extreme temperature differentials require maximum thermal insulation performance.

Refrigeration Systems

Cold storage and refrigerated distribution centers rely on double wall duct to prevent condensation and maintain precise temperature control.

High-Temp Applications

Process heating systems, commercial kitchens, and industrial exhaust where elevated temperatures require superior insulated ductwork.

Our Commitment

Why SIDCO

Memphis's trusted manufacturer of premium spiral duct systems — delivering precision, quality, and service since day one.

10+

Years Experience

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Expert Fabrication

Every piece of double wall duct is manufactured using precision spiral-forming machinery by skilled technicians who understand the demands of real HVAC projects.

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Premium Materials Only

We never compromise on raw material quality. Our steel is sourced from certified mills and meets all relevant ASTM and SMACNA specifications.

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Custom Project Support

Whether you need a single diameter or a complete system with multiple sizes, our team works closely with you to fabricate exactly what your project demands.

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Fast Turnaround

Standard sizes ship immediately from our Memphis facility. Custom orders are produced and dispatched within 1–3 business days so your project stays on schedule.

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Dedicated Customer Service

From quote to delivery, our knowledgeable team is available to assist with product selection, sizing, shipping coordination, and any technical questions.