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Tuesday, February 20, 2024

TWDB Application Guidelines

 TWDB Installation Guidelines

     TWDB is a Covalence (formerly Raychem) product that has been around for many years.   TWDB stands for Thermofit Wraparound Duct Bands and these would be used to seal up the joints on high velocity industrial duct work to eradicate air leaks at those joints.  Available in 3" and 4" widths, TWDB is sold in rolls that are 165 feet long.  Installers would cut their own strips of material from those rolls (cut lengths are explained on the box) and the installation is simple, easy -- and maybe most importantly:  NOT MESSY!

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Join duct sections that you will be sealing with TWDB using internal couplers or crimped end male/female type connections.  Apply sheet metal screws.  Two screws 180 degrees apart are usually sufficient.

Wipe the joint area to remove foreign materials.  Preheat joint to remove moisture and burn off any surface oil that may be present.  

Cut the TWDB (thermofit wraparound duct band) to the appropriate length.  Center the TWDB and wrap it around the duct joint (TWDB was once called TDAB)

Using the included supplied high temperature sealing tape (which holds the duct band in place during the shrink process), secure the loose TWDB end by taping in place.  TWDB should overlap onto itself. 

Using a standard propane torch, heat TWDB on all sides until it has shrunk uniformly and adhesive is showing at each end.  

Smooth down the overlap area with a gloved hand to ensure proper contact to the duct.  

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