O437 SERIES-93 (R2011)

Preface

The O437 Series on OSB and Waferboard comprises the second editions of CSA Standards O437.0, OSB and Waferboard, O437.1, Test Methods for OSB and Waferboard, and O437.2, Evaluation of Binder Systems for OSB and Waferboard. These Standards supersede the first editions, CAN3-O437.0 and CAN3-O437.1, published under a single cover in 1985, and CAN3-O437.2 published separately in 1986. It also supersedes an earlier CSA Standard, CAN3-O188.2-M78, Waferboard, which wa limited to that single product.

In addition to the change in name from Strandboard and Waferboard to OB and Waferboard, the major changes from the first edition include the addition of reference to the binder evaluation Standard, and reductions in the maximum permitted thickness swell. All clauses were also reviewed and modified where needed to improve clarity.

CSA Standard O437.1 was reviewed and minor changes were made for improved clarity and consistency of use. The tests have been grouped under four categories, specifically under dimensional, bond and bond durability, physical, and mechanical properties, and renumbered accordingly. The basic test methods described remain virtually unmodified, however.

CSA Standard O437.2 was also reviewed and some minor changes were made. Again, its basic provisions did not require modification.

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O437.0-93 - OSB and Waferboard

Scope

1.1

This Standard pertains specifically to a class of mat-formed structural panelboards made predominantly of wood strands or wafers of a minimum and controlled length, a controlled thickness, and a variable or predetermined width, bonded together with a waterproof and boilproof binder.

1.2

These panelboards are intended, and used extensively, for construction applications requiring durability, load-carrying capacities (strength and stiffness), and dimensional stability. Uses, however, are not limited to such applications.

1.3

This Standard covers two panelboard types identified as OSB (oriented strandboard) and waferboard, and establishes three grades for their manufacture.

1.4

Grade requirements are prescribed in terms of dimensional, physical, and mechanical property limits appropriate for characterizing a mat-formed, structural panel product intended primarily for common construction applications. Binder durability is specified in terms of bond strength after a two-hour boil test.

1.5

This Standard specifies grade and other marks for OSB and waferboard.

1.6

This Standard does not preclude the manufacture of OSB or waferboard with specified properties in addition to or in excess of those for grades in this Standard.

1.7

This Standard does not identify specific construction applications for the different grades and thicknesses. Tests and criteria required to characterize the product for special construction uses, or other applications, are not specified.

Note: Methods and criteria for the determination of the structural capabilities of panel products vary from country to country, and approval for the use of a product for a specific structural application is the responsibility of the governing code or regulatory authority.

Appendix A of CSA Standard O437.1 lists a number of test methods that have been used to evaluate the structural performance capabilities of OSB and waferboards for specific end uses.

1.8

This Standard does not apply to exterior bonded panelboards made wholly or in part of particles, flakes, fibres, or strands other than as defined herein.

Note: This is not intended to imply that such other panels are not suitable for similar construction end uses. The limitation in this Standard to a specific type of particle is based on a history of proven performance in building construction of boards made of wafers.

1.9

This Standard does not apply to OSB and waferboard products that are evaluated and marked solely in accordance with CSA Standard CAN/CSA-O325.0.

Note: OSB and waferboard may be evaluated and marked as complying with more than one Standard. Such panels are required to comply with all applicable requirements for each Standard identified on the panel.

1.10

The values given in SI (metric) units are the standard. The values in parentheses are for information only.

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O437.1-93 - Test Methods for OSB and Waferboard

Scope

1.1

This Standard provides sampling, measurement, and test procedures for the verification of compliance of OSB and waferboard with the requirements of CSA Standard O437.

1.2

The properties required to be assessed for verification of compliance with O437.0 are identified in Table 1. Test procedures for additional properties that are required for certain markets or uses are identified in Table 2. Both Tables summarize, for each property, the units, test method, size of specimen(s), number of specimens per panel, and the conditioning

requirements.

1.3

This Standard does not provide test methods for the assessment of end-use performance or for the determination of engineering properties.

Note: Some test methods for panel products that have been or may be used for these purposes are identified in Appendix A and Appendix B.

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O437.2-93 - Evaluation of Binder Systems for OSB and Waferboard

Scope

1.1

This Standard provides test procedures and performance criteria for the evaluation of binder systems for bonding strands or wafers in the manufacture of OSB and waferboard conforming to the requirements of CSA Standard O437.0.

1.2

CSA Standard O437.0 specifies that the agent used for binding the wood furnish may be any adhesive or process that meets or exceeds the criteria of this Standard for resistance to moisture, heat, fungi, acid, alkali, and creep.

This Standard establishes test procedures and performance criteria selected to demonstrate that under prescribed laboratory conditions

(a) the binder will provide the product properties specified in CSA Standard O437.0;

(b) the binder will not contribute to a greater level of creep than that found representative of OSB or waferboard made with phenol-formaldehyde binders;

(c) the loss of strength and stiffness of the OSB or waferboard made with the binder, on exposure to selected environments and treatments, will not exceed that found representative of the OSB or waferboard furnish;

(d) the amount of acidic material present in the binder will not reduce the pH level of the test panel product below that found representative of the OSB or waferboard furnish.

Note: The intent of this Standard is to establish that the binder, in addition to producing a board conforming to the requirements of CSA Standard O437.0, will also perform at a level at least equivalent to phenol-formaldehyde binders when tested under controlled laboratory conditions.

1.3

This Standard specifies performance criteria based upon the properties of laboratory-made test boards manufactured, in accordance with the prescribed conditions, with phenol-formaldehyde binders commercially in use in 1984 for the manufacture of OSB and waferboard.

1.4

This Standard applies to new phenol-formaldehyde binders as well as to non-phenol-formaldehyde binders.

1.5

Use of a binder conforming to the criteria of this Standard does not reduce the responsibility of the panelboard manufacturer to manufacture a product meeting all the requirements of CSA Standard O437.0.

1.6

The performance criteria in this Standard do not apply to commercially produced board. They have been established on the basis of, and for, the comparison of performance of boards manufactured under prescribed laboratory conditions.

1.7

This Standard does not provide test methods or criteria for the assessment of end-use performance or for the determination of engineering properties.

1.8

This Standard does not address toxicity of the binder or board or of products of degradation in fire.

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