We manufacture the highest quality fiberglass reinforced products for clients throughout the world.

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FRP’s high strength characteristics
combine with its light weight nature to produce a strength-to-weight ratio that continually out performs other materials on the market.

Industrial Fiberglass Reinforced Duct


FRP products have tremendous corrosion resistance properties that result in a longer life expectancy with lower required maintenance than most other available material options.


The wide variety of manufacturing processes available combined with the numerous resin  and reinforcement combinations make FRP products extremely easy to tailor for your specific needs.

Spunstrand® Inc. has been manufacturing underslab HVAC ductwork for over fifty years in both insulated and non-insulated forms. Insulated and non-insulated ductwork is available in, but not limited to, standard sizes 2″ diameter through 144″ diameter.

Industrial Fiberglass Reinforced Duct
The standard guide specification we use is centered around the National Bureau of Standards PS 15-69 and/or the new SMACNA Thermoset FRP Duct construction manual.

Our mine and tunnel ventilation ducts maintain a MSHA approval as a Class 1 rated duct system, and have been used in mining and tunneling applications now for 54 years.

Spunstrand® Inc. manufactures both Zero-Leak (ZL) and Balancing Dampers (BA) for the corrosive fume handling industry for a variety of environments and applications.
Industrial Fiberglass Reinforced Duct
Spunstrand® Inc. manufactures a wide variety of FRP filament wound media vapor phase scrubbers. The vessels range from passive venting up to 46,000 CFM within a single vessel.
Spunstrand® Inc. has a dedicated facility for manufacturing chemical and water storage tanks, carbon scrubbers and custom FRP products that will serve our primary industrial and municipal customers as well as emerging markets.

For over 50 years, Spunstrand® Inc. has furnished miles of underslab HVAC duct, above ground industrial and municipal duct systems and various special applications. Installations are in every state and foreign countries. All these years and miles of duct have produced a multitude of reliable services available to engineers, contractors and architects.

Our services include:

  • Duct sizing and layout assistance
  • Trenching and backfill considerations
  • Full structural calculations for burial, pressure, vacuum, etc.
  • A unique system for underslab in boot buried dampers
  • Design assistance with flex connections and expansion boots
  • Field joint procedures and demonstrations
  • On-site factory training
  • Carbon vessel design, selection and sizing
  • Absorbtion media selections
  • Shop drawing reviews for factory manifolded considerations
  • Quality control procedures
  • Visual inspection criteria
  • CSI format specs as word or pdf files

Highlights, News, & Notices

Spunstrand Thermal Insulation Manufacturer License # T1494 [State of CA, Bureau of Electronic and Appliance Repair, Home Furnishings and Thermal
Ending the Thermal Distribution Efficiency Discussion LinkedIn: https://www.linkedin.com/company/professional-code-consulting-llc?trk=prof-following-company-logo Facebook: https://www.facebook.com/procodeconsulting/