The Structural Insulated Panel Association announced that it will sponsor aspect ratio testing on shear walls built with SIPs. Funded by both SIPA and the USDAForest Products Laboratory, the testing aims to determine the allowable wall height to width ratio (aspect ratio) for SIP shear walls in high wind or seismic regions.

Currently, design professionals and engineers working with SIP shear walls in commercial buildings are limited to the testing data available from individual SIP manufacturers. Although SIP walls are given structural equivalency to wood frame walls for residential buildings in the International Residential Code, there is no mention of SIP shear walls in the International Building Code for nonresidential buildings.

According to Tom Williamson, who is representing SIPA on the testing advisory committee, the testing will likely demonstrate that SIP shear walls can be designed with an aspect ratio of up to 3.5:1, the same ratio used for conventional wood frame wall systems.

“Our goal is to provide design professionals with the tools they need to engineer shear walls with SIPs,” said Williamson. “When completed, the goal is to have the test results incorporated into the American Wood Council's Special Design Provisions for Wind and Seismic standard, which is referenced in the International Building Code.”

Providing a code-reference aspect ratio that is equivalent with conventional wood framing will make SIPs more cost competitive for commercial projects in high wind and seismic areas.  

“This testing will benefit the entire SIP industry by making it easier for architects and engineers to specify SIPs in nonresidential buildings,” said SIPA Executive Director Bill Wachtler. “These segments are crucial to the growth of the SIP industry and we want to compete on a level playing field with other types of construction.”

 The testing is scheduled to begin in July at the NAHB Research Center in Upper Marlboro, Md. A special NAHB Research Center advisory committee has been formed to oversee the testing that includes representatives from the NAHB Research Center, the American Wood Council, the International Code Council Evaluation Service, the Forest Products Laboratory, and representatives of SIPA.