We Keep the World Flowing



Flow-liner® hvac equipment

During research and development of alternative uses for CIPP, Flow-Liner® discovered that their Sewer and Drain systems could be multi-functional when paired with the proper materials. 

Flow-Liner® cip-duct materials

Flow-Liner® newest specialty liner and resin - CIP-DUCT®. This system expands the benefits of Cured-in-Place lining to include HVAC applications, specifically underground duct lining. CIP-Duct® eliminates infiltration inside of pipes, conduits and ducts. The CIP-Duct® liner has an impregnable membrane that stops liquid and gas infiltration

Cip-duct® testing & certification

Flow-Liner's CIP-Duct® Systems has been evaluated by IAMPO and found to be in accordance with Uniform Evaluation Service (IAPMO ER #484). For more information, please contact a Flow-Liner® representative to attain access to Flow-Liner's technical page.  CIP-Duct® is Engineer Tested to a minimum life expectancy of 50+ years and helps protect against dangerous asbestos materials and mold growth

Meets or exceeds the following standards:

  • ASTM F1216 for Rehabilitation of Existing Pipes, Conduits and Ventilation Systems
  • ASTM D648-16 Method B Deflection Temperature of Plastics Under Flexural Load
  • ASTM G21-15 Determining Resistance of Synthetic Polymeric Materials to Fungi
  • ASTM B117 Salt Spray (Fog) Test

HVAC Lining Projects by our Certified Installers


The Moo Moo Car Wash, serving nine Ohio locations, boasts as “the greenest, cleanest around.”With recycled water, high efficiency equipment, and biodegradable soaps, Moo Moo insures the lowest environmental impact in the car wash industry. Moo Moo discovered one of their underground vacuum lines had a separation at a 90-degree fitting. The separation was causing a loss of vacuum power. Excavation was undesirable as the line spanned under the driveway and equipment.

A certified Flow-Liner® installer cleaned the vacuum line and installed Flow-Liner® Cured-In-Place Duct (CIP-Duct®) Liner. The liner covered and sealed the separation at the 90° fitting, resolving the issue with no excavation necessary.


In 1989, the Coshocton Fire Department moved to a new facility capable of providing housing for the firefighters and accommodating new technology and community needs. Many years later, the new facility was found to have deteriorating underground exhaust vents and in need of a trenchless technology solution. 

A certified Flow-Liner® Installer effectively lined the deteriorating underground exhaust ducts by means of Flow-Liner® HVAC Cured-in-Place-Duct (CIP-Duct®) lining. Despite a dramatic transition in the duct from 7” to 12” and a 45-degree bend, the installer completed the duct lining in only two days and with NO EXCAVATION or disruption of the fire department’s daily functions.