PS20 American Softwood Lumber  


This Voluntary Product Standard establishes and maintains, through a consensus process and in the public interest, standard sizes (both in metric1 and conventional units) and general requirements for developing grades of softwood lumber. It is implemented through an internationally recognized accreditation and certification program, the purpose of which is to provide for uniform, industry-wide grade marking and inspection of softwood lumber.

This Standard also provides a basis for the coordination of the grades of the various species of softwood lumber, the assignment of design values to lumber when called for, and the preparation of grading rules applicable to each species. The provisions of this Standard apply to structural lumber manufactured from hardwood species or lumber manufactured from foreign species when the species is included in rules certified by the Board of Review. It is not intended to be used either as grading rules or as purchase specifications. Italicized notes in this Standard are non-mandatory.