CSA Preface This is the second edition of CSA O325, Construction sheathing, which is an adoption, with Canadian deviations, of the NIST (National Institute of Standards and Technology) Voluntary Product Standard PS 2-10, Performance Standard for Wood-Based Structural-Use Panels (June 2011). It supersedes the previous edition published in 2007 as CSA O325 (adopted NIST PS 2-04). The CSA Technical Committee on Wood-Based Panel Products believes that this adoption provides a suitable standard for Canadian manufacturers, engineers, building officials, and consumers. This CSA Group Standard provides requirements for Canadian applications in its Canadian deviations. In addition, by adopting NIST PS 2, with clearly identified Canadian deviations, the Committee has moved to eliminate market confusion regarding a number of subtle differences between the documents. This Standard is a performance-based Standard. It was prepared to provide an alternative means of specifying wood-based panel products for selected applications in wood-frame construction. Rather than prescribing panel makeup, this Standard establishes the minimum physical, bond durability, and structural performance criteria appropriate for floor, wall, and roof sheathing in light frame construction. Minimum load-carrying capacity and maximum deflection levels at specified loads are established at standard framing member spacings of 400, 500, and 600 mm (16, 20, and 24 in), and for some applications at spacings of 800, 1000, and 1200 mm (32, 40, and 48 in). The marking system used in this Standard identifies the recommended uses of products and the maximum framing member spacing at standard loads. The span mark corresponds to the recommended maximum spacing expressed in inches. Technical differences between this Standard and NIST PS 2 are clearly listed as Canadian deviations. Unless otherwise specified in the Canadian deviations, the requirements of NIST PS 2 apply. In the opinion of the Technical Committee, these differences reflect considerations necessary to satisfy building code assumptions and do not represent discrepancies in required characteristics. This Standard does not include engineering design values for construction sheathing, nor does it suggest methods for calculating such values. For information about design values for construction sheathing, consult CSA O86, Engineering design in wood. Scope 1.1 This Voluntary Product Standard primarily establishes structural criteria for assessing the acceptability of wood-based structural-use panels for construction sheathing and single-floor applications and provides a basis for common understanding among the producers, distributors, and the users of these products. The standard does not address non-structural issues such as resistance to biological agents. Applications other than construction sheathing and single-floor sheathing may require additional engineering considerations that are not covered by this document. 1.2 This Standard covers the performance requirements, adhesive bond performance, panel construction and workmanship, dimensions and tolerances, marking and moisture content of structural-use panels. 1.3 This Standard includes test methods to determine compliance and a glossary of trade terms and definitions. A quality certification program is provided whereby qualified testing agencies inspect, sample, and test products for qualification under this Standard. Information regarding industry practices for reinspection is provided in Appendix A. A flowchart depicting the qualification process is provided in Appendix B. Information on the maintenance, history, and current edition of the Standard is provided in Appendix C. Recommended thickness labeling is provided in Appendix D. Information on labeling regulations from NIST Handbook 130 is provided in Appendix E. Information on environmental attributes of structural panels are provided in Appendix F and information on formaldehyde emissions is provided in Appendix G. 1.4 This Standard incorporates the International System of Units (SI) as well as customary units of measurement. The values given in SI units are the standard. The values given in parentheses are for information only. In conversion of customary units where exact placement is not an issue, such as nail spacing, approximate conversions to SI units are made to yield more easily recognizable numbers. In critical matters, such as panel thickness, exact conversions to SI units are made. For nominal customary units, actual dimensions in SI units are given. 1.5 Advisory notes in this Standard shall not be considered mandatory.