The Spiral Duct Manufacturers Association, better known as SPIDA, is an organization focused on promoting the use of round ductwork and flat-oval duct. The organization is comprised of nearly 90 member companies throughout the United States and Canada.

The members of SPIDA represent some of the most experienced and knowledgeable members of the spiral duct community, including manufacturers and related suppliers. SPIDA’s continuous goal is to promote the use of spiral round and flat-oval duct in HVAC construction through research, testing and education.

SPIDA’s operations are administered by its president, board of directors and committees. Many of the board members have over 30 years of experience in the industry and bring a wide range of talents, experience and regional knowledge. These volunteers spend countless hours promoting the use of spiral duct and aiding its membership.

Each year, SPIDA hosts a general membership meeting in conjunction with the annual AHR Expo, including the 2018 expo in Chicago. The program usually consists of a speaker on an important industry or business topic as well as an update on SPIDA’s testing and research efforts. SPIDA invites everyone to attend and see how we can help grow the profitability of your business, whether you are a manufacturer or supplier to the spiral duct industry. Additionally, each year SPIDA hosts an annual conference at a unique venue. The 2017 annual meeting was in Minneapolis; the 2018 annual meeting will be in New Orleans. 

Minneapolis visit

In May, SPIDA members gathered for their annual meeting in Minneapolis. The meetings consisted of industry speakers, roundtable discussions and presentations from vendors. There was plenty of time to interact with fellow members at several social gatherings. The conference started with a group dinner in a relaxed atmosphere and ended with an outing to a Minnesota Twins ballgame. In between there were lunches and social hours. Along with the group discussions, these events were opportunities to share ideas, insights and forge relationship that span generations and across North America. These meetings provided the opportunity to network with some of the most experienced and creative minds in the spiral industry.


The core mission of SPIDA is displayed in its research and testing. It is almost universally understood that spiral round and flat-oval duct are the most efficient way to move air in an HVAC system. This is not only due to low total pressure losses, but also because of negligible leakage rates and strength. The testing that SPIDA conducts ensures that the data and research is available to backup these benefits. The most recent project completed by SPIDA’s technical committee was flat-oval testing — the results of which will appear in the next version of the Sheet Metal and Air-Conditioning Contractors’ National Association’s HVAC Duct Construction Standards manual. Testing on friction and acoustic insertion losses of dual-wall and internally lined spiral duct are currently being developed. 

A test report is available to SPIDA members at the Brad Thomas research contributor level in advance of the SMACNA publication and provides gauge/reinforcement charts based on pressures. These charts are based on maximum allowable deflection.

This deflection testing gives SPIDA the opportunity to promote flat-oval ducts in applications where space limitations do not allow the installation of spiral duct. Flat-oval ducts experience lower pressure losses at a given flow rate when compared with a rectangular duct of the same cross-sectional area. Upcoming insertion-loss testing will assist SPIDA to continue promoting spiral round and flat-oval duct.  

Become a member

SPIDA’s annual dues are structured to allow companies to choose the appropriate level of participation:

  • Companies who want to support research and testing efforts and have a leadership role in the organization join as a Brad Thomas research contributor and pay $1,100 per year.
  • Companies who are less involved but want access to the specialized information published by SPIDA and the opportunity to participate in meetings become industry supporters and pay $575 per year.
  • Vendors and suppliers may join for $350.

For more information on SPIDA, please visit and follow us on LinkedIn.

Scott Witherow is a vice president at California-based sealants and adhesives maker Design Polymerics. He is also on the Spiral Duct Manufacturers Association’s board of directors. Contact him at