What is a Thermal Barrier?
- Thermal barriers are made from resins that create a “thermal break” between the inner and outer surfaces of aluminum fenestrations.
- Thermal barriers reduce heat loss or heat gain through the aluminum.
- Thermal barriers improve the U-value characteristics of finished systems.
- Thermal barriers are about energy conservation, U-values and government codes
- 70 percent of aluminum fenestration systems produced in North America contain a thermal break
- Primarily used in colder climates to reduce heat loss
- Increasing use of thermal barriers to reduce heat gain and also reduce heat loss
- Developers, architects and designers are demanding better performance in terms of power usage
- Stricter government regulations to reduce power usage in buildings to combat environmental concerns
- Aluminum, if it is to retain its market superiority in terms of its structural integrity, will have to achieve better performance in terms of U-values
- The use of thermal barriers will assist manufacturers to achieve improved LEED performance
Currently, there are two principal types of thermal barriers used in North America: polyamide thermal barrier strip and pour & debridge (P&D).
Polyamide Thermal Barrier Strips
- Pre-extruded profiles made from polyamide with 25 percent glass-fiber
- Locked in place in “pockets” extruded into two separate (inner and outer) aluminum extrusions
- Enables finished assemblies with different finishes and colors on each surface
- Aluminum extrusion pockets need to be “knurled” prior to insertion of the polyamide profiles – and “rolled” to create a structurally-secure finished assembly
- The polyamide profiles can be supplied with ”sealing-wire” which give a reliable seal and enhanced shear strength when activated by heat e.g. – powder-coating
- The aluminum extrusions can be finished either before or after installation of the polyamide strips
Pour & Debridge
- P&D is the most widely used system for thermal barriers in North America
- It is a polyurethane-based system
- An Iso is mixed with a resin at the point of assembly and the mixture is poured into a barrier channel in the aluminum extrusion
- After pouring and curing, the barrier channel is “debridged”
- The debridging process creates the separation between the inner and outer surfaces
- A mechanical locking system on the extrusion is recommended to eliminate possible problems with dry shrinkage