AltusGroup (Bethlehem, Pa., USA) reported on Nov. 15 that its CarbonCast High Performance Insulated Wall Panels have received International Code Council Evaluation Service (ICC-ES) acceptance criteria for the C-GRID carbon fiber grid truss system used to connect the inner and outer wythes of the precast concrete wall panels. The official criteria is called AC422 - Proposed Acceptance Criteria For Semicontinuous Fiber-Reinforced Grid Connectors Used In Combination With Rigid Insulation In Concrete Sandwich Panel Construction.
The acceptance criteria means the ICC-ES has approved a method for evaluating product samples from each AltusGroup precaster licensed to fabricate the system. Successful completion of the tests, such as load capacity and freeze-thaw cycling will result in ICC-ES issuing an Evaluation Service Report (ICC-ESR) number certifying that the manufacturer is producing the CarbonCast precast sandwich wall panel system using C-GRID according to established standards. Many municipalities and building jurisdictions require an ICC-ESR certification before allowing use of a structural building product.
It is expected that continual product testing success by the 13 AltusGroup precasters will result in ICC broadening the AC422 acceptance criteria to include the entire precast assembly, not just the carbon fiber grid connector. The CarbonCast High Performance Insulated Wall Panel would be the only structural precast sandwich wall panel of similar nature and use on the market to earn that level of acceptance criteria.
"This is a definitive third-party validation for our technology for the dozens of independent research and engineering studies we've already conducted," said Larbi Sennour, Ph.D. P.E. S.E., chairman of AltusGroup's Technical Committee.
The ICC approval follows an evaluation of the system by an impartial ICC-ES board during several public comment review periods and sessions. AltusGroup engineers provided data and calculations to demonstrate the performance of the product and the intent of the criterion.
CarbonCast High Performance Insulated Wall Panels feature a C-GRID carbon fiber grid shear connector. The high strength of carbon fiber grid enables full composite action within the panel, while its relatively low thermal conductivity results in negligible thermal transfer throughout the panel. As a result, CarbonCast High Performance Insulated Wall Panels provide continuous insulation (c.i.) to meet the ASHRAE 90.1 standards and can be used to significantly reduce energy consumption related to heating or cooling a structure.
Members of the AltusGroup Technical Committee involved with the ICC certification were Jason Lien (Encon United), Harry Gleich (Metromont), Steve Brock (Gate Precast), Larbi Sennour, Dr. Thomas Harmon (Washington University of St. Louis), Sami Rizkalla (North Carolina State University), Pat Hynes (Knife River Prestress Division) and Ken Baur (High Concrete Group LLC).