On March 14, there was a lamination bond failure in a cross-laminated timber floor panel being used in the construction at Oregon State University's new Oregon Forest Science Complex. No one was injured and the panel was removed.
The manufacturer of the CLT panel, DR Johnson, located in Riddle, Oregon, is a member of APA-The Engineered Wood Association and APA is working with the manufacturer to review the incident and implement corrective actions. APA-trademarked cross-laminated timber is manufactured to meet the requirements of the ANSI/APA PRG 320 Standard for Performance-Rated Cross-Laminated Timber (CLT). As the trademarking agency, APA audits the mill for compliance to the PRG 320 standard and reviews quality management systems in place at the mill on a regular basis.
Early investigations indicate that a process change in the manufacturing introduced temperature variations in the laminations that inadvertently caused premature curing of the adhesive, resulting in dry glue lines and poor bonding. This could result in localized areas where the CLT lamination bond performance did not meet the requirements of the CLT standard, and therefore did not perform as expected.
The manufacturer has addressed this manufacturing anomaly and implemented additional manufacturing and quality control measures. APA is auditing these process changes for effectiveness and to ensure continual compliance with the PRG 320 Standard.
APA is working with both the manufacturer and the investigation team formed to evaluate the CLT panel that failed, as well as all other CLT product on the jobsite. All CLT involved will be evaluated against the criteria stipulated in the PRG 320 Standard.
APA is confident that cross-laminated timber manufactured in conformance with the ANSI/APA PRG 320 Standard for Performance-Rated Cross-Laminated Timber will meet the structural performance requirements for the intended applications in construction. The PRG 320 Standard builds on a foundation of strong CLT performance in Europe and around the world, and details rigorous processes and requirements for the North American industry.
About ANSI/APA PRG 320
ANSI/APA PRG 320 provides requirements and test methods for qualification and quality assurance for performance-rated CLT, which is manufactured from solid-sawn lumber or structural composite lumber. The bi-national standard is a first for the U.S. and Canada. The first version of the standard was approved by ANSI for publication on December 20, 2011. Since then, three new versions have been published in 2012, 2017, and 2018.
APA is a national standards developer accredited by ANSI and the Secretariat of ANSI/APA PRG 320. APA is also a product certification agency for CLT accredited under ISO/IEC 17065, Conformity Assessment - Requirements for Bodies Certifying Products, Processes, and Services.