Spiral ductwork is the most efficient mode to transport air in HVAC systems. Spiral pipe is gaining popularity due to its contemporary aesthetic appeal and efficiency. Architects often leave this pipe exposed due to its attractive, clean appearance. It is often painted to blend into the ceiling but can be highlighted against the surrounding background. Spiral ductwork is made on a special machine that feeds slit metal into an interlocking seam, forming a spiral pattern pipe. 


Spiral pipe made its debut in 1956, after founders Erling Jensen and Leif Andresen spent years inventing "a more economical mode of transporting air." Although the technology was new, it quickly gained traction worldwide. By 1970, the demand was so high Spiro International opened a location in the United States originally intended to only be a sales office. The demand only exponentially increased, soon they were building the machines here in the United States. 

Advantages of Spiral Ductwork

If space is not an issue and efficiency and aesthetics are a priority, then spiral ductwork could be your solution.


  • Lower fabrication cost - according to SMACNA duct design manual, spiral is 60% the cost of rectangular duct.


  • Superior aesthetics - architects typically prefer round duct in exposed ceiling applications for a couple of reasons. (1) the spiral ductwork paints and finishes very clean (2) spiral pipe/flat oval is easier to paint and finish then the alternative square duct. 


  • Options - countless options for size, style, gauge, double-wall (which consists of an inner perforated metal surrounded first by insulation and then finished by sleeving it into a typical spiral pipe jacketing), material type and finish are available for spiral duct.


  • Application - not only does round duct excel in a commercial HVAC application but for many other applications as well. Consider using round duct for dust collection, particulate ventilation, industrial, mining projects.


  • More efficient HVAC system - the surface area of spiral is much less than rectangular, which translates to less air friction and a more efficient system. (ie a 12" X 12" duct has a stretch-out of 48" which equates to a 13.1" round duct or a 41" stretch - a savings of nearly 15%).


  • Faster installation - traditionally rectangular ductwork is built and assembled in 5' sections, spiral, however, is typically built and installed in 10' sections.


  • Lower installation cost - spiral requires fewer connections than rectangular ductwork, which lowers the margin for errors on properly sealing the joints - not to mention the time and energy savings.


  • Less air loss - not only does spiral ductwork require less transverse duct connections, but spiral has no longitudinal connections. At best, it has been difficult to achieve less than a 5% airflow loss with rectangular. Spiral averages a 1-2% air loss. As building efficiency has become an important goal - spiral pipe can reduce waste drastically.


  • Less noise pollution - spiral ductwork absorbs the noise of the equipment far better than rectangular ductwork. Rectangular ductwork tends to reverberate sound throughout the system.

Our HVAC Spiral Ductwork

Our spiral ductwork is held together either by an interlocking standard lateral seam, spaced on 5" centers. The regular spiral duct does not have the corrugated stiffening beads, but for heavier applications we do have the capability to add these corrugation beads. We offer a variety of options to meet whatever your needs might be, including double-wall.

Spiral Ductwork Standard Lateral Seam

Standard 5" Lateral Seam

Spiral Ductwork | Corrugated Lateral Seam

Corrugated 5" Lateral Seam

Choose from the following options:

Pipe Diameter

  • 4" - 24" in every nominal increment 

  • 24" - 56" in 2" increments

  • 60" 

Metal Type

  • Galvanized Steel (G-90)

  • Aluminum .032 & .040

  • Paint Lock* (24 ga & 22 ga)

  • Stainless Steel* (24 ga)

  • PVS*

Pipe Length

  • Any size from 12" - 240" (standard length is 120")

Metal Gauge

  • 18

  • 20

  • 22

  • 24

  • 26

Only select gauges are available with this type of metal.


United Team Mechanical products are manufactured in accordance with the latest SMACNA, ASHRAE and SPIDA standards. In an on-going effort to improve our products, United Team Mechanical reserves the right to revise the design and/or specifications of its products as technology advances or applicable standards change.