The NWCB has just recently completed an update of the NWCB 401 Document, Suspension Systems for Acoustical Lay-in Ceilings Seismic Design Categories D, E & F. The Document now references the current 2021 IBC, which references the 2016 ASCE-7. There were a number of minor changes, such as correctly illustrating the Seismic Separation Joint in Figure 7, and updated references to the document.
The Oregon State Building Codes, Pierce County Building Department and the City of Bellevue, have provided input on the revisions to the Document and have received a copy of the updated version. In your review, if you have any questions, please don’t hesitate to reach out to us and please, share the document with everyone in your office.
The NWCB first established this document in 2005 to provide clarification to its members and the larger construction, architectural community and municipalities with an easy-to-read document clarifying the intent of the code. This widely used document provides the various standards for the installation of suspension systems for acoustical lay-in ceiling. The latest revision of the document (March 2022) is available for download below.