Which part of the NDS focuses on sawn lumber?

The correct answer is that Part 4 of the National Design Specification (NDS) is dedicated specifically to sawn lumber. This section provides the necessary guidelines for the design and application of sawn wood products, including structural properties, allowable stresses, and adjustment factors for various uses. The inclusion of this information is crucial for engineers and designers working with sawn lumber, as it ensures that they can safely and effectively select the appropriate materials based on the specific requirements of their projects.

Parts of the NDS address different aspects of wood design. For instance, the other parts cover areas such as design values for wood-based materials, engineered wood products, and connections. Understanding where sawn lumber fits into the overall context of wood design helps professionals locate the relevant information needed for their specific applications, ensuring compliance with best practices and safety standards in structural engineering.