Recently, steel framing members have enjoyed increasing popularity both because of their improving economic viability relative to wood and the advantages associated with their fire resistive characteristics. In spite of this, one of the significant problems, now widely recognized by the construction industry, continues to plague built assemblies that incorporate steel-framing members. In these built assemblies, the steel framing creates a “thermal bridge”. The transfer of heat across this “thermal bridge” manifests itself in the form of increased energy consumption, larger heating and cooling bills, and the occurrence of a phenomenon commonly referred to as “ghost marking.” A number of attempts to solve these problems have been proposed, yet all have had significant disadvantages that severely limit or entirely eliminate their practical application. As a result, the construction industry continues its search for steel framing members that possess superior thermal characteristics. ThermaChannel™ steel framing members answer this need.

“The bad news is that research studies show that steel framing can be a thermal disaster.”

  1. EXTERIOR SHEATHING (1/2´´ PLYWOOD)
  2. 1/4´´ AIRSPACE
  3. MECHANICAL FASTENER
  4. THERMALLY IMPROVED CHANNEL
  5. CAVITY INSULATION
  6. MECHANICAL FASTENER
  7. 1/4´´ AIRSPACE
  8. INTERIOR SHEATHING (1/2´´ GWB)
  1. EXTERIOR SHEATHING (1/2´´ PLYWOOD)
  2. 1/2´´ AIRSPACE
  3. MECHANICAL FASTENER
  4. THERMALLY IMPROVED CHANNEL
  5. CAVITY INSULATION
  6. MECHANICAL FASTENER
  7. 1/2´´ AIRSPACE
  8. INTERIOR SHEATHING (1/2´´ GWB)

WHY THERMACHANNEL™

ThermaChannel™ steel framing members significantly improve the cumulative R-value of walls.

  • ThermaChannel™ steel framing members virtually eliminate “ghost marking” by dramatically reducing stud/cavity temperature differentials.
  • ThermaChannel™ steel framing members present no obstruction to mechanical fasteners.
  • ThermaChannel™ steel framing members work within industry standardized framing systems.
  • ThermaChannel™ steel framing members possess structural characteristics similar to, or better than, standard members.
  • ThermaChannel™ steel framing members are designed for use in fire-rated assemblies.
  • ThermaChannel™ steel framing members require no use of “add on” insulate material such as coatings or weather-stripping. And most importantly...
  • ThermaChannel™ steel framing members require little or no cost increase.

ThermaChannel™ steel framing members are both energy efficient and cost effective: truly a winning combination.

Configurations for ThermaChannel™ steel framing members have been tested by Oak Ridge National Laboratory’s Buildings Technology Center. These tests, performed in accordance with ASTM C-236 Standard Test Method, were used to establish the thermal performance of three-8 ft wide test walls. The first wall incorporated standard C-Shaped steel framing members. The second wall utilized ThermaChannel™ steel framing members with a 1⁄4” indentation in each flange. The third wall used ThermaChannel™ steel framing members with a 1⁄2” indentation in each flange. In an effort to establish consistency between test samples, all components, with the exception of steel framing members, were re-used in each wall. In addition, all steel framing members, including standard C-shaped stud sections, were fabricated from identical galvanized steel stock.

TEST WALL COMPONENTS

  • 1⁄2” plywood sheathing [all joints shaped]
  • 6” steel framing members 0.035” thick, 1 3⁄4” flange [24” o.c.]
  • R-19 Kraft-faced fiberglass batt insulation [full width]
  • 1⁄2” gypsum wall board sheathing [all joints taped]

INCREASED R-VALUE

“The problem is that metal studs conduct heat many times faster than wood, serving as a sort of heat-loss superhighway.”

ThermaChannel™ steel framing members, configured with a 1⁄4 inch indentation in each flange, improved the over-all R-value of walls by a factor of 16%! An even greater improvement should be expected for walls incorporating 3-5/8” framing.

REDUCED GHOST MARKING

“A report from US Steel cited ‘ghost marks’ caused by steel studs as the “single-most significant unsolved technical problem that prevents the general acceptance of steel studs’.”

ThermaChannel™ steel framing members with a 1⁄4 inch indentation in each flange reduce interior surface-temperature differentials by a factor of 29%! Members with a 1⁄2” indentation in each flange reduce differentials by 43%; thereby virtually eliminating “ghost marking”! An even greater reduction should be expected for walls using 3-5/8” framing.

Thermographic imaging clearly illustrates the dramatic improvement made by ThermaChannel™ steel framing over standard steel framing. This close-up comparison reveals that areas of thermal transfer for both 1⁄4” and 1⁄2” indentations are concentrated around the location of fasteners. Standard steel framing allows a high level of thermal transfer along its entire length and width.

Thermo graphic imaging clearly illustrates the dramatic improvement made by ThermaChannel™ steel framing over standard steel framing. This close-up comparison reveals that areas of thermal transfer for both 1⁄4” and 1⁄2” indentations are concentrated around the location of fasteners. Standard steel framing allows a high level of thermal transfer along its entire length and width.

COMPARE THE ALTERNATIVES

Most attempts to overcome the “thermal disaster” created by steel framing members fall prey to the one fundamental factor that severely limits their practical application.

Cost Increase VS. Thermal Improvement

As a result, the desirability of steel framing, particularly with regard to residential construction, has been drastically reduced.

THERMACHANNEL™

A minimum 9% to 16% improvement to the cumulative R-value of walls.

A minimum 29% to 43% reduction in stud/cavity surface-temperature differentials.

Little or no cost increase.

Compare ThermaChannel™ steel framing members with any other system. You’ll find that they provide the most cost-effective solution for problems associated with “thermal bridging.” When used in conjunction with insulating sheathings, they create the most energy efficient steel-framed assemblies available.

  1. 1/2´´ GWB SHEATHING
  2. MECHANICAL FASTENER
  3. R-21 BATT INSULATION
  4. 6´ X 1 5/8´´ METAL STUDS @ 24´´ O.C.
  5. MECHANICAL FASTENER
  6. 1/2´´ PLYWOOD SHEATHING
Method of Improvement: Increase batt insulation from R-19 to R-21.
Improvement Realized: 4.4% in cumulative R-value of wall. No improvement in stud/cavity differential.
Cost Increase: Slight cost increase.
Other Disadvantages: Does not address issue of thermal bridging. “Ghost marking” still a problem.
  1. 1/2´´ GWB SHEATHING
  2. MECHANICAL FASTENER
  3. 3 5/8´´ X 1 5/8´´ METAL STUDS @ 24´´ O.C.
  4. R-1 BATT INSULATION
  5. MECHANICAL FASTENER
  6. 5/16´ FOAM WEATHER-STRIPPING
  7. 1/2´´ PLYWOOD SHEATHING
Method of Improvement: Attach 5/16” foam weather-stripping to one flange.
Improvement Realized:
6% in cumulative R-value of wall. 10% in stud/cavity differential.
Cost Increase:
Significant increase.
Other Disadvantages:
Weather-stripping can be damaged.
  1. 1/2´´ GWB SHEATHING
  2. MECHANICAL FASTENER
  3. 3 5/8´´ X 1 5/8´´ METAL STUDS @ 24´´ O.C.
  4. R-1 BATT INSULATION
  5. MECHANICAL FASTENER
  6. 7/8´´ HAT CHANNELS
  7. 1/2´´ PLYWOOD SHEATHING
Method of Improvement: Attach 7/8” steel hat-channels to one flange.
Improvement Realized:
18% in cumulative R-value of wall. 22% in stud/cavity differential.
Cost Increase:
Significant increase.
Other Disadvantages:
Changes wall thickness, increasing cost associated with trim at openings.
  1. 1/2´´ GWB SHEATHING
  2. MECHANICAL FASTENER
  3. 3 5/8´´ X 1 5/8´´ METALSTUDS @ 24´´ O.C.
  4. R-1 BATT INSULATION
  5. MECHANICAL FASTENER
  6. 1/2´ XPS SHEATHING
Method of Improvement: Substitute 1/2” XPS for plywood sheathing.
Improvement Realized:
44% in cumulative R-value of wall. 50% in stud/cavity differential.
Cost Increase:
Significant increase, especially if plywood still needed for shear.
Other Disadvantages: Foam is HCFC based.

Structural calculations for ThermaChannel™ steel framing members have been provided by several well established consulting engineering firms. Various configurations are calculated to allow a comparison of structural properties against material utilization and thermal-improvement characteristics. Calculations for ThermaChannel™ steel framing members demonstrate that a substantial improvement in thermal performance may be achieved without necessitating a significant change in either material usage or structural value.

[Calculated thickness: 0.0478”]

 

 

CONVENTIONAL STEEL FRAMING

Tested R-value of Wall: 9.58

Tested Stud/Cavity ΔT: 6.5°F

THERMACHANNEL™ STEEL FRAMING MEMBER

[1/4” Indentation]

Tested R-value of Wall: 10.44 [+9%]

Tested Stud/Cavity ΔT: 4.6°F [-29%]

THERMALCHANNEL™ STEEL FRAMING MEMBER

[1/2” Indentation]

Tested R-value of Wall: 11.12 [+16%]

Tested Stud/Cavity ΔT: 3.7°F [-43%]