PS20-20, Revision 1 American Softwood Lumber Standard  


This Standard pertains to softwood lumber. It establishes standard sizes and requirements for development and coordination of the lumber grades of the various species, the assignment of design values when called for, and the preparation of grading rules applicable to each species. It provides for implementation of the Standard through an accreditation and certification program to assure uniform industry-wide marking and inspection.

It establishes principal trade classifications and lumber sizes for yard, structural, factory and shop use and provides for the classification, measurement, grade marking of rough and dressed sizes of lumber items. Terms and procedures are defined to provide a basis for the use of uniform methods in the grading, inspection, measurement and description of softwood lumber. It includes the organization and functions of the American Lumber Standard Committee, the Board of Review, and the National Grading Rule Committee. Commercial names of the principal softwood species, definitions of terms used in describing standard grades of lumber and commonly used industry abbreviations are also provided.