Preface 

This is the sixth edition of CSA O141, Canadian standard lumber . It supersedes the previous editions published in 2005, 1991, 1970, 1965, and 1959 previously known as Softwood lumber. The major change in this edition is that this Standard no longer applies to only Canadian-manufactured lumber. It now also applies to all manufactured lumber imported into and exported out of Canada. This Standard is intended to be consistent with NIST PS 20, American Softwood Lumber Standard, and ensures the Canadian and American grade marking systems are interchangeable. It does so by a) establishing standard sizes and requirements for development and coordination of the lumber grades of the various species; b) defining industry terms and procedures to provide a basis for the use of uniform methods in the grading, inspection, measurement, and description of softwood lumber; c) providing commercial names of the principal Canadian-grown species and species combinations, as well as definitions of terms used in describing standard grades of lumber and commonly used industry abbreviations; and d) providing for the implementation of the Standard through an accreditation and certification program to assure uniform industry-wide marking and inspection. In addition, this Standard specifies the organization, structure, and functions of the Canadian Lumber Standards Accreditation Board (CLSAB), which oversees the certification programs of Canadian standard lumber. This Standard also specifies that the CLSAB approves the grading rules for Canadian standard lumber. The National Lumber Grades Authority (NLGA) has established and maintains the approved grading rules. This Standard was prepared by the Subcommittee on Canadian Standard Lumber, under the jurisdiction of the Technical Committee on Solid and Engineered Wood Products and the Strategic Steering Committee on Forest Products, and has been formally approved by the Technical Committee. 

Scope 

1.1 Application

 This Standard specifies requirements pertaining to the quality and uniformity of lumber and establishes the designation “Canadian standard lumber” (see Clause 4) for lumber that meets those requirements. This Standard covers the following: a) accreditation board and agency responsibilities (see Clause 5); b) measurement (see Clause 6); c) standard sizes (see Clause 7); d) grading rule requirements (see Clause 8); e) identification (i.e., grade stamps and certificates) (see Clause 9); and f) determination of design properties (see Clause 10). This Standard applies to lumber produced and consumed in Canada, lumber exported from Canada, and lumber imported into Canada. This Standard provides for the grading of structural lumber by both visual and mechanical means. This Standard also includes detailed Annexes covering lumber terminology and lumber industry abbreviations. 

1.2 Exclusions

 This Standard does not cover trade practices, grades (other than grading rules and identification), the details of accreditation board and grading agency inspection procedures, or strength and related properties of lumber. 

1.3 Hardwood lumber

 The provisions of this Standard apply to species when the species is included in rules approved by the accreditation board. Although this Standard applies to softwood lumber, it may be applied to hardwood lumber used in applications that ordinarily use softwood lumber. 

1.4 Terminology

 In this Standard, “shall” is used to express a requirement, i.e., a provision that the user is obliged to satisfy in order to comply with the Standard; “should” is used to express a recommendation or that which is advised but not required; and “may” is used to express an option or that which is permissible within the limits of the Standard. Notes accompanying clauses do not include requirements or alternative requirements; the purpose of a note accompanying a clause is to separate from the text explanatory or informative material. Notes to tables and figures are considered part of the table or figure and may be written as requirements. Annexes are designated normative (mandatory) or informative (non-mandatory) to define their application. 

1.5 Units 

The values given in yard/pound units are the units of record for the purposes of this Standard. The values given in parentheses are for information and comparison only. In keeping with the practice of lumber manufacturers throughout North America, sizes in this Standard are given in board measure units, which are expressed in yard/pound units (see Clause 6.1). Equivalent SI (metric) sizes, rounded to the nearest millimeter, are given in parentheses for the sake of convenience in use and in commercial transactions. Note: See Annex E for more about how metric dimensions have been calculated for this Standard.