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ZEN Industries eNewsletter:
May 2021

Advantages of Double Wall Spiral Duct

Energy Efficiency, Less Noise, Saves Space

Double Wall Spiral in Commercial Ceiling InstallationAs an experienced fabricator of HVAC duct, ZEN Industries has supplied traditional rectangular duct, industrial and specialty duct, spiral duct, and double wall spiral duct.

Based on decades of service in supplying large commercial projects and working with project managers and architects, we know that double wall spiral duct offers some simple but powerful advantages.

What is double wall spiral? As the name suggests, double wall consists of two concentric spiral ducts, with a smaller diameter duct fitted inside a larger one and both separated by a layer of insulation.

While spiral duct is itself more efficient than traditional rectangular duct, double wall spiral takes that efficiency a step further. Double wall provides for a more consistent airflow, much less leakage, and it helps maintain consistent air temperature throughout the system. This in turn means less work for the HVAC system and significantly less energy usage.

Noise, or the lack thereof, is another outstanding feature of double wall spiral duct. The double wall structure and insulation contribute to much quieter airflow. In commercial and government applications like help desk operations and emergency call centers, this can be a critically important feature. Even in an average retail location, double wall spiral helps businesses maintain a welcoming atmosphere, which can be disrupted by noisy AC systems.

Double wall spiral saves space, as does basic spiral duct. Rectangular ductwork can use up to 3 inches of extra space, especially at connection and reinforcement points. And, spiral duct looks good, so good that architecturally exposed duct is now often used as an integral part of interior design.

Double Wall Spiral from ZEN Industries

Spiral Duct on Construction SiteAt ZEN, we offer a complete line of double wall spiral and fittings.

Each piece is fabricated with an inner metal liner surrounded by insulation and covered by a solid metal outer shell. All of ZEN Industries' spiral double wall and fittings meet or exceed 3rd Edition 2005 SMACNA standards.

Spiral Double Wall HVAC available with:

  • 1", 2", or 3" insulation
  • Galvanized steel
  • Stainless steel
  • Galvanneal (paint grip)
  • Aluminum
  • PCD (Polyvinyl Coated Ductwork)

The sheet metal liner protects the insulation from airflow while it stops fiberglass erosion. The insulation in our double wall spiral and fittings has both acoustical and thermal benefits. It can reduce radiated noise by 25 dB or more, compared to fiberglass duct board. ZEN's 1-inch insulation has a thermal conductance of 0.27 Btu/hr x sq. ft. x degree Fahrenheit.

Double wall spiral available with insulation thicknesses of 2-inches (0.13 Btu/hr xsq. ft. x degree Fahrenheit) and 3-inches (0.09 Btu/hr x sq. ft. x degree F).
Dual-wall pipe and fittings are joined by slip connectors and fitting collars. The inner liner connectors are extended to mate the inner liners before the outer shells are mated.
You can learn more by visiting the ZEN Industries website, especially our HVAC Double Wall Spiral page.

A Closer Look

Architectural Ductwork, Double SpiralDouble Wall Spiral saves money in other ways too, by mitigating the four most common issues with duct installation projects.

These are: damage on the job site, errors in duct insulation wrap, erosion over time (due to high pressure and turbulent airflow), and condensation which can cause mold, reduce air quality, and even damage ceiling tiles with water stains.

Double wall spiral is simply a more robust product. It’s concentric pipe construction with an insulated layer makes it far less susceptible to damage in transport and during installation.

Insulating traditional rectangular duct often takes place on the job site using insulating wraps. With efficient, double wall spiral, labor time in insulation is eliminated. Modern HVAC systems don’t struggle to put warm air through cold ducts in winter or vice versa in summer. The insulated ducts maintain the temperature of the air within.

The double wall structure, by its nature, provides a barrier that prevents the insulation from being worn and degraded overtime by the airflow itself. This same design feature, with its highly efficient insulation, prevents condensation and the problems that flow from introducing moisture into heating and ventilation systems.

Altogether, the investment of incorporating double wall spiral duct into your commercial or community construction project represents both long-term savings and a higher comfort level, including a completed project with a reputation satisfies tenants and maintains its value over time. 

ZEN’s Comprehensive Array
of HVAC Duct and Products

In addition to Spiral Ductwork, ZEN features Double Wall Spiral, Rectangular Ductwork, PCD Ductwork, and Specialty Ductwork.

At ZEN, we can assist your project from estimating and take-offs through techniques that eliminate field measuring and optimize field labor.

When you take all of the savings ZEN can deliver, we have proven we can save 25% to 35% off of traditional duct acquisition methods.

Interested in learning more about how ZEN Industries can fulfill your proejct needs for HVAC ducts and fittings? Call us at 877-600-0274, or visit our Contact Us page today!


Success is All About Great Service

Founded in 1999 on a set of unbreakable core principles, ZEN strives to provide top-quality fabrication, advice, and planning for our customers.

The quality of our HVAC duct work is of the highest caliber and our price is competitive with the best in the industry. Of course, ZEN Industries Inc. gains its edge with unbeatable service, and service means people - it's about our experienced personnel and the relationships we build with each and every customer.

At ZEN Industries, we believe success is all about great service. Our affordable HVAC shop drawings, estimating services, and duct fabriction can be reached att 877-600-0274, or visit our Contact Us page today!

Learn more at www.ZENindustries.com

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