Voluntary Product Standard  
 
PS 1 -xx19 
 
Structural Plywood  
 
 
 
Ballot Draft  March  2019  
 
(changes indicated by strikeout /underline ) 
 
With changes from St anding Committee Meeting June 19, 2019  
 
 
 
 i 
 Table of Contents  
1. SCOPE  ................................ ................................ ................................ ................................ . 
2. TERMINOLOGY  ................................ ................................ ................................ ...................  
2.1 Back  ................................ ................................ ................................ .............................  
2.2 Bond classifications  ................................ ................................ ................................ ...... 
2.3 Borer holes  ................................ ................................ ................................ ...................  
2.4 Broken grain  ................................ ................................ ................................ .................  
2.5 Butt joint  ................................ ................................ ................................ .......................  
2.6 Centers  ................................ ................................ ................................ .........................  
2.7 Center gap  ................................ ................................ ................................ ....................  
2.8 Characteristics, growth ................................ ................................ ................................ .. 
2.9 Characteristics, open  ................................ ................................ ................................ .... 
2.10  Check  ................................ ................................ ................................ ...........................  
2.11  Class I, II  ................................ ................................ ................................ ......................  
2.12  Construction (panel construction)  ................................ ................................ ..................  
2.13  Core  ................................ ................................ ................................ .............................  
2.14  Critical Section  ................................ ................................ ................................ ..............  
2.15  Crossband  ................................ ................................ ................................ ....................  
2.16  Crossband gap and center gap  ................................ ................................ .....................  
2.17  Delamination  ................................ ................................ ................................ .................  
2.17.1.  Knotholes, pitch pockets, splits and gaps  ................................ ..............................  
2.17.2.  Exposure 1  ................................ ................................ ................................ ...........  
2.17.3.  Exterior  ................................ ................................ ................................ .................  
2.18  Edge splits  ................................ ................................ ................................ ....................  
2.19  Exposure 1 bond classification  ................................ ................................ ......................  
2.20  Exterior bond classification  ................................ ................................ ............................  
2.21  Face  ................................ ................................ ................................ .............................  
2.22  Finger joint  ................................ ................................ ................................ ....................  
2.23  Group  ................................ ................................ ................................ ...........................  
2.24  Heartwood  ................................ ................................ ................................ ....................  
2.25  Inner plies  ................................ ................................ ................................ .....................  
2.26  Jointed inner plies  ................................ ................................ ................................ .........  
2.27  Knot ................................ ................................ ................................ ..............................  
2.28  Knotholes  ................................ ................................ ................................ .....................  
2.29  Lap ................................ ................................ ................................ ...............................  Formattedii 
 2.30  Layer  ................................ ................................ ................................ ............................  
2.31  Lot ................................ ................................ ................................ ................................  
2.32  Major panel axis  ................................ ................................ ................................ ............  
2.33  Mill specification  ................................ ................................ ................................ ............  
2.34  Moisture content  ................................ ................................ ................................ ...........  
2.35  Moisture resistant adhesive  ................................ ................................ ...........................  
2.36  Panel thickness ................................ ................................ ................................ .............  
2.37  Patches  ................................ ................................ ................................ ........................  
2.38  Performance Category                                                                                                     . 
2.39  Performance testing  ................................ ................................ ................................ ...... 
2.40  Pitch pocket  ................................ ................................ ................................ ..................  
2.41  Pitch streak  ................................ ................................ ................................ ...................  
2.42  Plugs  ................................ ................................ ................................ ............................  
2.43  Plugged inner plies (also referred to as solid inner plies.)  ................................ ..............  
2.44  Ply ................................ ................................ ................................ ................................  
2.45  Plywood  ................................ ................................ ................................ ........................  
2.46  Plywood classification  ................................ ................................ ................................ ... 
2.47  Prescriptive specification  ................................ ................................ ...............................  
2.48  Reference value  ................................ ................................ ................................ ............  
2.49  Repair  ................................ ................................ ................................ ...........................  
2.50  Rough grain  ................................ ................................ ................................ ..................  
2.51  Sapwood  ................................ ................................ ................................ ......................  
2.52  Scarfed joint  ................................ ................................ ................................ ..................  
2.53  Shim  ................................ ................................ ................................ .............................  
2.54  Shop -cutting panel  ................................ ................................ ................................ ........  
2.55  Span rating  ................................ ................................ ................................ ...................  
2.56  Split ................................ ................................ ................................ ..............................  
2.57  Sub-face (sub -back)  ................................ ................................ ................................ ...... 
2.58  Touch -sanding  ................................ ................................ ................................ ..............  
2.59  Veneer  ................................ ................................ ................................ ..........................  
2.60  Wane  ................................ ................................ ................................ ............................  
2.61  White pocket  ................................ ................................ ................................ .................  
2.61.1 Light white pocket  ................................ ................................ ................................ ...........  
2.61.2 Heavy white pocket  ................................ ................................ ................................ .........  
2.62  Wood failure (percent) ................................ ................................ ................................ ... 
2.63  Working Face  ................................ ................................ ................................ ...............  
3    REFERENCE PUBLICATIONS  ................................ ................................ ..............................  iii 
 4   PLYWOOD CLASSIFICATION  ................................ ................................ ................................ . 
4.1 General ................................ ................................ ................................ .........................  
4.2 Bond classification  ................................ ................................ ................................ ........  
4.2.1  Exposure 1 plywood  ................................ ................................ ................................ ...... 
4.2.2  Exterior plywood  ................................ ................................ ................................ ...........  
4.3 Grade  ................................ ................................ ................................ ...........................  
5    REQUIREMENTS  ................................ ................................ ................................ ....................  
5.1 General ................................ ................................ ................................ .........................  
5.2 Wood species  ................................ ................................ ................................ ...............  
5.2.1  Species groups  ................................ ................................ ................................ .............  
5.2.1.1  Species segregation  ................................ ................................ ................................ . 
5.2.2  Species for faces and backs  ................................ ................................ .........................  
5.2.3  Species for inner plies  ................................ ................................ ................................ ... 
5.2.4  Species classified by test ing ................................ ................................ .........................  
5.3 Synthetic repairs  ................................ ................................ ................................ ...........  
5.3.1  Synthetic fillers  ................................ ................................ ................................ .........  
5.3.2  Synthetic shims, patches, and plugs  ................................ ................................ .........  
5.4 Grade description of veneers  ................................ ................................ ........................  
5.4.1  Grade N veneer (intended for natural finish)  ................................ ..............................  
5.4.2  Grade A veneer (suitable for painting)  ................................ ................................ .......  
5.4.3  Grade B veneer  ................................ ................................ ................................ ........  
5.4.4  Grade C veneer  ................................ ................................ ................................ ........  
5.4.5  Grade C plugged veneer  ................................ ................................ ...........................  
5.4.6  Grade D veneer  ................................ ................................ ................................ ........  
5.5 Veneers and layers  ................................ ................................ ................................ .......  
5.5.1  Veneer thickness  ................................ ................................ ................................ ...... 
5.5.2  Parallel laminated layers  ................................ ................................ ...........................  
5.5.3  Scarfed veneers  ................................ ................................ ................................ .......  
5.6 Panel grades  ................................ ................................ ................................ ................  
5.6.1  Marine  ................................ ................................ ................................ ......................  
5.6.2  Decorative panels  ................................ ................................ ................................ ..... 
5.6.3  Underlayment  ................................ ................................ ................................ ...........  
5.6.4  Concrete form panels  ................................ ................................ ...............................  
5.6.5  Structural I panels  ................................ ................................ ................................ ..... 
5.6.6  Special Exterior  ................................ ................................ ................................ ........  
5.6.7  Overlays  ................................ ................................ ................................ ...................  
5.7 Adhesive bond requirements for a panel or a lot  ................................ ............................  
5.7.1  Exposure 1  ................................ ................................ ................................ ...............  
5.7.2  Exterior  ................................ ................................ ................................ .....................  
5.8 Panel constructions and workmanship  ................................ ................................ ..........  
5.8.1  Crossband gaps and center gaps ................................ ................................ ..............  
5.8.2  Veneer requirements  ................................ ................................ ................................  
5.8.3  Sanded panels ................................ ................................ ................................ ..........  
5.8.4  Unsanded and touch -sanded panels  ................................ ................................ .........  
5.8.5  Span ratings for unsanded and touch -sanded panels  ................................ ................  iv 
 5.8.6  Performance testing qualification requirements for span -rated panels  .......................  
5.8.7  Performance testing qualification requirements for other than span -rated panels  .......  
5.8.7.1  General  ................................ ................................ ................................ ................  
5.8.7.2  Performance testing  ................................ ................................ .............................  
5.8.7.3  Mill specification  ................................ ................................ ................................ ... 
5.9 Scarf and finger jointed panels  ................................ ................................ ......................  
5.9.1  Strength requirements for scarf and finger jointed panels  ................................ ..........  
5.9.2  Scarf joint bond performance for Exposure 1 and Exterior plywood  ...........................  
5.9.3  Finger joint bond performance for Exposure 1 and Exterior plywood  .........................  
5.10  Dimensiona l tolerances and squareness of panels  ................................ ........................  
5.10.1  Size tolerances  ................................ ................................ ................................ ..... 
5.10.2  Performance Category and Thickness tolerances  ................................ .................  
5.10.3  Squareness and straightness  ................................ ................................ ................  
5.11  Moisture content  ................................ ................................ ................................ ...........  
5.12  Loading or packing ................................ ................................ ................................ ........  
6   SPECIMEN PREPARATION AND TESTING  ................................ ................................ ............  
6.1 Bond classification  ................................ ................................ ................................ ........  
6.1.1  General  ................................ ................................ ................................ ....................  
6.1.2  Specimen preparation (see appendix B for sampling for reinspection)  .......................  
6.1.3  Tests for Exposure 1 and Exterior plywood.  ................................ ..............................  
6.1.4  Test for determination of moisture content (oven -drying method)  ..............................  
6.1.5  Scarf and finger -joint tests  ................................ ................................ ........................  
6.2 Structural performance ................................ ................................ ................................ .. 
6.2.1  Tests for performance under concentrated static and impact loads  ............................  
6.2.2  Test for performance under uniform loads  ................................ ................................ . 
6.2.2.1  General  ................................ ................................ ................................ ................  
6.2.2.2  Equipment  ................................ ................................ ................................ ............  
6.2.2.3  Specimen preparation  ................................ ................................ ...........................  
6.2.2.4  Test procedure  ................................ ................................ ................................ ..... 
6.2.3  Test for panel bending  ................................ ................................ ..............................  
6.2.4  Test for planar shear strength  ................................ ................................ ...................  
6.2.4.1  General  ................................ ................................ ................................ ................  
6.2.4.2  Specimen preparation  ................................ ................................ ...........................  
6.2.4.3  Test procedure  ................................ ................................ ................................ ..... 
6.2.5  Test for shear -through -the-thickness strength  ................................ ...........................  
6.2.5.1  General  ................................ ................................ ................................ ................  
6.2.5.2  Specimen preparation  ................................ ................................ ...........................  
6.2.5.3  Test procedure  ................................ ................................ ................................ ..... 
7 GRADEMARKING AND CERTIFICATION  ................................ ................................ ............  
7.1 Certification ................................ ................................ ................................ ...................  
7.2 Qualified inspection and testing agency  ................................ ................................ ........  
7.3 Panel marking  ................................ ................................ ................................ ...............  
7.4 Voiding marks  ................................ ................................ ................................ ...............  
8 EFFECTIVE DATE  ................................ ................................ ................................ ................  
9 STANDING COMMITTEE  ................................ ................................ ................................ ..... 
 v 
 APPENDIX  
 
A Species Grouping (mandatory)  ................................ ................................ ..........................  
A1 General  ................................ ................................ ................................ .............................  
A2 Grouping in practice  ................................ ................................ ................................ ..........  
A3 Species grouping  ................................ ................................ ................................ ..............  
A3.1 Assignment of a species group shall be as follows  ................................ ............................  
 
B Reinspection Practices (non mandatory)  ................................ ................................ ...........  
B1 General  ................................ ................................ ................................ .............................  
B2 Request for reinspection  ................................ ................................ ................................ ... 
B3 Responsibility of the buyer  ................................ ................................ ................................  
B4 Responsibility of the seller  ................................ ................................ ................................ . 
B5 Responsibility of the qualified inspection agency conducting the reinspection  ....................  
B6 Cost and assistance  ................................ ................................ ................................ ..........  
B7 Resinspection procedures and settlement  ................................ ................................ .........  
B7.1 Condition of plywood  ................................ ................................ ................................ .........  
B7.2 Sampling for panel grade, size, and thickness reinspections ................................ ..............  
B7.3 Plywood panel grade, size, and thickness reinspections  ................................ ....................  
B7.4 Sampling for adhesive bond quality reinspections ................................ ..............................  
B7.5 Plywood adhesive bond quality reinspections  ................................ ................................ .... 
 
C General Information and Co mments on Current Edition (non mandatory)  ..........................  
C1 Current edition, PS 1 -09 that became effective December 31, 2009  ................................ .. 
C1.1  Labeling of panel thickness  ................................ ................................ ...............................  
C1.2  Formaldehyde appendix  ................................ ................................ ................................ .... 
C1.3  Environmental attributes and green building rating systems  ................................ ...............  
C1.4  Technical re visions  ................................ ................................ ................................ ...........  
C2 History of the project  ................................ ................................ ................................ .........  
C2.1  PS 1 -74 Construction and Industrial Plywood  became effective August 1, 1974  .................  
C2.2  PS 1 -83 Construction and Industrial Plywood  became effective December 30, 1983  .........  
C2.3  PS 1 -95 Construction and Industrial Plywood  became effective September 7, 1995  ..........  
C2.4  PS 1 -07 Structural Plywood  became effective February 26, 2007  ................................ ...... 
 
D (non mandatory)  ................................ ................................ ................................ ................  
D1 Recommend thickness labels  (non-mandatory)  ................................ ................................ . 
D2 Regulations on labeling  ................................ ................................ ................................ ..... 
 
E Labeling Guidelines Based on the Uniform Packaging and Labeling Regulations of NIST  
 Handbook 130 v2009 and Handbook 133  (non mandatory)  ................................ ...............  
E1 Summary  ................................ ................................ ................................ ..........................  
E1.1  ................................ ................................ ................................ ................................ .........  
E2 Background  ................................ ................................ ................................ ......................  
E2.1  ................................ ................................ ................................ ................................ .........  
E2.2  ................................ ................................ ................................ ................................ .........  
E2.3  ................................ ................................ ................................ ................................ .........  
E3 Scope and definitions  ................................ ................................ ................................ ........  
E3.1  ................................ ................................ ................................ ................................ .........  
E3.1.1  Consumer package  ................................ ................................ ................................ ...........  
E3.1.2  Non-consumer package  ................................ ................................ ................................ .... 
E3.2  ................................ ................................ ................................ ................................ .........  
E3.2.1  Label ................................ ................................ ................................ ................................ . 
E3.2.2  Principal display panel  ................................ ................................ ................................ ...... 
E4 Declaration of identity and responsibility  ................................ ................................ ............  
E4.1  ................................ ................................ ................................ ................................ .........  
E4.2 Product identity  ................................ ................................ ................................ .................  vi 
 E4.3 Product responsibility  ................................ ................................ ................................ ........  
E4.3.1   ................................ ................................ ................................ ................................ .........  
E5 Declaration of q uantity  ................................ ................................ ................................ ...... 
E5.1  ................................ ................................ ................................ ................................ .........  
E5.2  ................................ ................................ ................................ ................................ .........  
E5.3 General rules  ................................ ................................ ................................ ....................  
E5.3.1   ................................ ................................ ................................ ................................ .........  
E5.3.2   Rules specific to bi -dimensional commodities (no comparative rules for  
 non-consumer)  ................................ ................................ ................................ ..................  
E5.3.3   ................................ ................................ ................................ ................................ .........  
E5.3.4   ................................ ................................ ................................ ................................ .........  
E6 Prominence and placement  ................................ ................................ ...............................  
E6.1 General  ................................ ................................ ................................ .............................  
E6.2 Location  ................................ ................................ ................................ ............................  
E6.3 Style of type and lettering  ................................ ................................ ................................ .. 
E6.4 Color contract  ................................ ................................ ................................ ...................  
E6.5  Free area  ................................ ................................ ................................ ..........................  
E6.6 Parallel quantity declaration  ................................ ................................ ..............................  
E6.7 Height and proportion of numbers and letters  ................................ ................................ .... 
 
F Wood Structural Panels as Green Building Materials (non mandatory)  ..............................  
F1 Overview  ................................ ................................ ................................ ...........................  
F2 Green attributes of wood  ................................ ................................ ................................ ... 
F3 Sustainable forest management programs  ................................ ................................ ........  
F4 Major green bui lding rating systems  ................................ ................................ ..................  
 
GF Formaldehyde (non mandatory)  ................................ ................................ ........................  
G1 General  ................................ ................................ ................................ .............................  
G2 Formaldehyde regulations  ................................ ................................ ................................ . 
G2.1   ................................ ................................ ................................ ................................ .........  
G2.2   ................................ ................................ ................................ ................................ .........  
G2.3  California Air Resource Board (CARB) Air Toxic Control Measure for Composite  
 Wood Products  ................................ ................................ ................................ .................  
G3 Formaldehyde emission from PS 1 Plywood  ................................ ................................ ...... 
G3.1   ................................ ................................ ................................ ................................ .........  
TABLES  
Table 1  Classification of species  ................................ ................................ ................................ .... 
Table 2  Exposure 1 plywood grades  ................................ ................................ ..............................  
Table 3  Exterior plywood grades  ................................ ................................ ................................ .... 
Table 4  Panel constructions (minimum number of plies and layers)  ................................ ................  
Table 5  Characteristics prohibited or restricted in certain panel grades  ................................ ..........  
Table 6  Span ratings for sheathing and single -floor panels based on prescriptive specifications  ..... 
Table 7  Concentrated static and impact test performance criteria for panel testing according  
 to Section  6.2.1  ................................ ................................ ................................ .................  
Table 8  Uniform load performance criteria for panels tested according to Section 6.2.2  ..................  
Table 9  Species group classification te st criteria for other than span -rated panels  ..........................  
Table 10 Plywood thickness requirements  ................................ ................................ .....................  
Table A1 Clear wood property assignments  ................................ ................................ ...................  
Table A2 Source of data used to classify foreign species in Plywood Product Standard PS 1  .........  
Table D1 Recommended thickness label ing for unsanded, touch sanded and overlaid panels  ....... 
Table D2 Recommended thickness labeling for sanded panels  ................................ ......................  
 vii 
 FIGURES  
 
Figure 1 Finger -joints – location of scarfed portion of joints  ................................ ............................  
Figure 2 Shear test specimens  ................................ ................................ ................................ ...... 
Figure 3 Apparatus for heat durability  ................................ ................................ ............................  
Figure 4 Tension specimen for scarfed jointed panels  ................................ ................................ .... 
Figure 5 Specimen preparation  ................................ ................................ ................................ ...... 
Figure 6 Cleavage test, typical test specimen  ................................ ................................ ................  
Figure 7 Wedge or chisel used for cleavage test  ................................ ................................ ............  
Figure 8 Vacuum chamber test equipment  ................................ ................................ .....................  
Figure 9 Uniform -load test specime ns ................................ ................................ ............................  
 
  
1 
  
 
VOLUNTARY PRODUCT STANDARD PS 1 -0919 
STRUCTURAL PLYWOOD  
 
Effective May 1, 2010 -TBD 
 
(This Standard, which was initiated by APA - The Engineered Wood Association [formerly the 
American Plywood Association], has been developed under the Procedures for the 
Development of Voluntary Product Standards  of the U.S. Department of Commerce as a 
revision of PS 1 -0709, Structural  Plywood .) 
1. SCOPE  
 
1.1  This Voluntary Product Standard establishes requirements for the principal types and 
grades of structural plywood and provides a basis for common understanding among producers, 
distributors, and users of  the product.  
 
1.2  This Standard covers the wood species, veneer grading, adhesive bonds, panel 
construction and workmanship, dimensions and tolerances, marking, moisture content, and 
packaging of structural plywood intended for construction and industria l uses.  
 
1.3  Included in this Standard are 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 identified a s complying with this Standard.  
Information on species grouping is provided in Appendix A.  Information on reinspecting 
practices is provided in Appendix B.  Information on the maintenance, history, and current 
edition of the Standard is provided in Appen dix C.  Recommended thickness labeling is provided 
in Appendix D.  Information on labeling regulations from NIST Handbook 130 and NIST 
Handbook 133 are provided in Appendix E.  Information on environmental attributes of structural 
plywood is provided in App endix F and i Information  on formaldehyde emissions i s provided in 
Appendix GF. 
 
1.4  This Voluntary Product Standard incorporates the International System of Units (SI) as well 
as U.S. customary units of measurement.  In conversion of U.S. customary units where exact 
placement is not an issue, such as nail spacing, approximate conversions to S I units are made 
to yield more easily recognizable numbers.  In critical matters, such as panel thickness, more 
precise conversions to SI units are made.  For nominal U.S. customary units, actual dimensions 
in SI units are given.  The values given in SI un its are the standard.  The values in parentheses 
are for information only.  
 
1.5  Advisory notes in this Standard and Appendices B through G F are informational and  shall 
not be considered mandatory.  
2. TERMINOLOGY  
2.1 Back  
Back of a plywood panel — The side of a panel that is of lower veneer quality on any panel 
whose outer plies (front and back) are of different veneer grades.  
Back ply of a plywood panel — The outer veneer on the back side of a panel.   
2 
 2.2 Bond classifications  
Plywood is rated as Exposure 1 or Exte rior bond classification.  (See Section s 2.20 and 2.2 1 
4.2.) 
2.3 Borer holes  
Voids made by wood -boring insects, such as grubs or worms.  
2.4 Broken grain  
A separation on veneer surface between annual rings, such as leafing or shelling.  
2.5 Butt joint  
A straight join t in which the interface is perpendicular to the panel face.  An end butt joint is 
perpendicular to the grain.  
2.6 Centers  
Inner layers whose grain direction runs parallel to that of the outer plies.  Some centers consist 
of parallel laminated plies.  
2.7 Center g ap  
See Section 2.16.  
2.8 Characteristics, growth  
Discolorations, pitch streaks and knots that naturally occur in wood.  
2.9 Characteristics, open  
Irregularities such as splits, open joints, knotholes, loose knots, or wane.  
2.10 Check  
A lengthwise separation of wood fi bers, usually extending across the rings of annual growth, 
caused chiefly by strains produced in seasoning.  
2.11 Class I, II  
Term used to identify different classifications of concrete form panels. (See Section 5.6.4.)  
2.12 Construction (panel construction)  
Term referring to detailed manner in which veneers are assembled and/or thickness of veneer 
used, e.g., "4 -ply 3 -layer construc tion," "2.5 mm (1/10 in) face and back," etc.  
2.13 Core  
See Section 2.15.  
2.14 Critical Section  
A rectangular area measuring 305 mm (12 in) along the grain by full panel width that contains a 
knot or knothole requiring additional consideration.  (See Sections 5.4. 4.3, 5.4.6.2 and 5.4.6.3)  
2.15 Crossband  
Inner, or core, plies whose grain direction runs perpendicular to that of the outer plies.  Some 
crossbands consist of parallel laminated plies.  
2.16 Crossband gap and center gap  
An open joint extending through or partially  through a panel, which results when crossband or 
center veneers are not tightly butted.   
3 
 2.17 Delamination  
A visible separation between plies that normally receive adhesive at their interface and are 
firmly contacted in the pressing operation.  Wood characteris tics such as checking, leafing, 
splitting and broken grain are not to be construed as delamination.  
2.17.1  Knotholes, pitch pockets, splits and gaps  
For purpose of evaluation of delamination, areas coinciding with open knotholes, pitch 
pockets, splits, and gaps a nd other voids or characteristics permitted in the panel grade 
are not considered in evaluating ply separation.  
2.17.2  Delamination of Exposure 1  Panels  
In evaluating Exposure 1 panels, delamination in any bond line is not to exceed 19.4 cm2 
(3 in2) except where directly attributable to characteristics permitted in the grade as 
follows:  
 
Delamination associated with:  
 
(a) Knots and knotholes — Not to exceed the size of the knot or knothole plus a 
surrounding band not wider than 19.1 mm (3/4 in).  
(b) All other forms of permissible characteristics — Not to exceed the size of the 
characteristic.  
2.17.3  Delamination of Exterior  Panels  
For purposes of evaluation of Exterior panels for ply separation, the area coinciding with 
the grade characteristics noted in Section 2.17.1 is cons idered, and a panel is considered 
delaminated if visible ply separation at a single bond line in such area exceeds 19.4 cm2 
(3 in2). 
 
2.18  Depression  
A minor disruption of the panel surface with a smooth boundary.  
2.182.19 Edge splits  
Wedge -shaped openings in the inner plies caused by splitting of the veneer before pressing.  
2.192.20 Exposure 1 bond classification  
Bond classification for panels Plywood  suitable for uses not permanently exposed to the 
weather.  Panels classified as Exposure 1 are intended to r esist the effects of moisture on 
structural performance as may occur due to during  construction  delays , or other conditions of 
similar severity.  See Section 4.2.1.  
2.202.21 Exterior bond classification  
Plywood Bond classification for panels  suitable for repeated wetting and redrying or long -term 
exposure to weather or other conditions of similar severity.  See Section 4.2.2.  
2.212.22 Face  
Face of the plywood panel — The side of a panel that is of higher veneer quality on any 
panel whose outer plies (front and back) are of different veneer grades; either side of a 
panel where the grading rules draw no distinction between outer plies.  
Face ply of a panel — The outer veneer on the face of a panel.  Formatted:  Indent:  Left:  -0.03",  Outline  numbered  + Level:
2 + Numbering  Style:  1, 2, 3, … + Start at: 1 + Alignment:
Left + Aligned  at:  0.44" + Tab after:   0.84" + Indent  at: 
0.84",  Tab stops:   0.31",  List tab +  0.56",  Left 
4 
 2.222.23 Finger joint  
Term indicating the method by which p anels or sections of panels have been joined to create 
longer lengths or widths by means of a well -bonded series of sloped scarf cuts resembling 
fingers.  
2.232.24 Group  
Term used to classify species or panels covered by this Standard.  Species covered by this 
Stand ard are classified as Groups 1, 2, 3, 4, and 5.  See Table 1 and Appendix A for listing of 
species in individual groups.   Section 5.8.7 provides procedures for grouping of panels with 
species not listed in Table 1.  
2.242.25 Heartwood  
Nonactive core of a log general ly distinguishable from the outer portion (sapwood) by its darker 
color.  
 
2.26  Indent  
A disruption of  the panel surface with sharp  or distinct  edges.  
2.252.27 Inner plies  
Plies other than face or back plies in a panel construction.  Sub -face, sub -back, crossband and 
center are classed as inner plies.  
2.262.28 Jointed inner plies  
Crossband and center veneers with edges machine -squared to permit tightest possible layup.  
2.272.29 Knot  
Natural characteristic of wood that occurs where a branch base is embedded in the trunk of a 
tree.  Generally the size of a knot is distinguishable by (1) a difference in color of limb wood and 
surrounding trunk wood; (2) an abrupt change in growth ring width between knot and bordering 
trunk wood; and (3) a diameter of circular or oval shape described by  points where checks on 
the face of a knot that extend radially from its center to its side experience an abrupt change in 
direction.  
2.282.30 Knotholes  
Voids produced by the dropping of knots from the wood in which they were originally embedded.  
2.292.31 Lap 
A condition wh ere the veneers in the same ply are so placed that one piece overlaps the other.  
2.302.32 Layer  
A single veneer ply or two or more plies laminated with grain direction parallel.  Two or more 
plies laminated with grain direction parallel is a "parallel laminated lay er." 
2.312.33 Lot 
Any number of panels considered as a single group for evaluating conformance to this 
Standard.  
2.322.34 Major panel axis  
The direction parallel to the grain of the face and back plies.  Formatted:  Font: Not Bold
Formatted:  Font: Not Bold
Formatted:  Font: Bold
Formatted:  Indent:  Left:  -0.03",  Outline  numbered  + Level:
2 + Numbering  Style:  1, 2, 3, … + Start at: 1 + Alignment:
Left + Aligned  at:  0.44" + Tab after:   0.84" + Indent  at: 
0.84",  Tab stops:   0.75",  List tab + Not at  0.84" 
5 
 2.332.35 Mill specification  
A manufacturing specification based on product evaluation to be used for quality assurance 
purposes by the manufacturer and the qualified testing agency as defined in Section 7.2.  (See 
Sections 5.8.6.5. and 5.8.7.3.)  
2.342.36 Moisture content  
The weight of the water in wood expressed as a percent of t he weight of the oven -dry wood.  
(See Section 6.1.4.)  
2.352.37 Moisture resistant adhesive  
Adhesive capable of bonding plywood in a manner to satisfy the bond classification 
requirements of this Standard.  
2.362.38 Panel thickness  
Designated thickness subject to tolerances s pecified in this standard.  See Section 5.10.2 for 
thickness tolerances.  See Section 2. 38 40 for definition of Performance Category.  
2.372.39 Patches  
Inserts of sound wood or synthetic material in veneers or panels for replacing characteristics 
(open or growth).  "Boat" patches are oval -shaped with sides tapering in each direction to a 
point or to a small rounded end.  “Compound Boat” patches have multi ple rounded or pointed 
ends. "Router" patches have parallel sides and rounded ends.  "Sled" patches are rectangular 
with feathered ends.  
2.382.40  Performance Category                                                                                                     
A panel designation related to the panel thickness range that is linked to the nominal panel 
thickness designations used in the International Building Code (IBC) and International 
Residential Code (IRC).  For purposes of labeling, as defined in Section 7. 3, abbreviations PERF 
CAT, CAT or Category are permitted.  
 
ADVISORY NOTE:  The IRC and IBC specify a minimum 3/8 Performance Category for wall sheathing.  
 
2.392.41 Performance testing  
Tests that evaluate panel attributes typically required in the end -use applicatio ns as defined in 
this Standard.  
2.402.42 Pitch pocket  
A well -defined opening between rings of annual growth, usually containing, or which has 
contained, pitch, either solid or liquid.  
2.412.43 Pitch streak  
A localized accumulation of resin in coniferous woods which permea tes the cells forming resin 
soaks, patches, or streaks.  
2.422.44 Plugs  
Sound wood of various shapes, including among others, circular and dog -bone, for replacing 
portions of veneers.  Also synthetic plugs used to fill openings and provide a smooth, level, 
durable surface.  Plugs usually are held in veneer by friction until veneers are bonded into 
plywood.  Formatted:  Indent:  Left:  0", Tab stops:   0", Left + Not at 
0.63" 
6 
 2.432.45 Plugged inner plies (also referred to as solid inner plies.)  
Refers to C Plugged crossband and centers and additional limitations, as given in Section 5.8 .1. 
2.442.46 Ply  
A single veneer lamina in a bonded plywood panel.  (See also 2. 3032.) 
2.452.47 Plywood  
Plywood is a panel built up of sheets of veneer called plies, united under pressure by a bonding 
agent to create a panel with an adhesive bond between plies as strong as  or stronger than, the 
wood.  Plywood is constructed of an odd number of layers with grain of adjacent layers 
perpendicular.  Layers consist of a single ply or two or more plies laminated with parallel grain 
direction.  Outer layers and all odd -numbered la yers generally have the grain direction oriented 
parallel to the long dimension of the panel.  The layers with alternating grain direction equalize 
strains, reduce splitting, and minimize dimensional change and warping of the panel.  
2.462.48 Plywood classification  
Plywood is classified by bond classification and grade.  (See Section 4.)  
2.472.49 Prescriptive specification  
A specification based upon manufacturing parameters that define the approved product.  
2.482.50 Reference value  
The numerical value established for the mill specifi cation for a given mechanical or physical 
property.  
2.492.51 Repair  
Any patch, plug or shim.  
2.502.52 Rough grain  
Grain characteristics which prevent sanding to a smooth surface.  
2.512.53 Sapwood  
The living wood of lighter color occurring in the outer portion of a log.  Sometimes r eferred to as 
"sap."  
2.522.54 Scarfed joint  
A term indicating the method by which panels or veneer, or sections of panels or veneer, have 
been joined to create longer lengths or widths by means of a well -bonded, sloped cut.  
2.532.55 Shim  
A long, narrow repair of wood or sui table synthetic not more than 4.8 mm (3/16 in) wide.  
2.542.56 Shop -cutting panel  
Panel which has been rejected as not conforming to a standard grade because of deficiencies, 
other than adhesive bond quality, which prevent it from meeting the requirements of this 
Standard.  Blistered panels are not permitted within the category of “shop -cutting panel.”  
Localized delamination occurring as a result of a deficiency is permitted.  Shop -cutting panels 
are suitable for cut -up use where cutting elimi nates the deficiency in the portion of the panel 
salvaged.  The salvageable area shall be at least 85% of the area of the panel.  Such a panel 
must be identified with a separate mark as specified in Section 7.4.  
 
2.57  Sized for Spacing   
7 
 An optional panel mark indicating  that the panel manufacturer has sized the panel to allow for 
industry recommended panel installation spacing.  
2.552.58 Span rating  
An index number, based on customary inch units, that identifies the recommended maximum 
center -to-center support spacing for the specified end use under normal use conditions.  Spans 
are defined for end uses such as roof, subfloor, and single floor.  As a matter of convention, 
spans are typically specified by a single index number for single floor (Floor  24 o.c.), while roof 
and subfloor are often combined in a fractional format.  For example, a span rating of 32/16 
designates a roof span of 32 inches and a subfloor span of 16 inches.  As a matter of 
convention, a span rating of 20 is designated for spans of 19.2 inch . 
2.562.59 Split  
Lengthwise separation of wood fibers completely through the veneer, caused chiefly by the 
manufacturing process or handling.  
2.572.60 Sub-face (sub -back)  
The ply adjacent to the exposed face (or back) of a parallel laminated outer layer.  
2.582.61 Touch -sanding  
A sizing operation consisting of a light surface sanding to thickness dimension in a sander.  
Sander skips to any degree are admissible.  
2.592.62 Veneer  
Thin sheets of wood of which plywood is made.  Also referred to as "plies" in the bonded panel.  
2.602.63 Wane  
Thin to open areas in veneer sheets that result from outer log surface irregularities.  Some wane 
areas contain bark inclusions.  For grading, wane is classed as an open characteristic.  
2.612.64 White pocket  
A form of fungal decay ( Fomes pini ) that attacks most conif ers but has never been known to 
develop in wood in service.  In plywood manufacture, routine drying of veneer effectively 
removes any possibility of the fungus surviving.  Also known as white speck.  
2.6164.1 Light white pocket  
Advanced beyond incipient or stain stage to a point where pockets are present and 
plainly visible, mostly  small and filled with white cellulose; generally distributed with no 
heavy concentrations; pockets for the most part separate and distinct; few to no holes 
through the veneer.  
2.6164.2 Heavy white pocket  
Contains a great number of pockets, in dense concentrations, running together and at 
times appearing continuous; holes extend through the veneer but wood between pockets 
appears firm.  At any cross section extending across the widt h of the affected area, 
sufficient wood fiber shall be present to develop not less than 40% of the strength of clear 
veneer.  Brown cubicle and similar forms of decay which have caused the wood to 
crumble are prohibited.  Formatted:  Indent:  Left:  0.04",  Outline  numbered  + Level:
2 + Numbering  Style:  1, 2, 3, … + Start at: 1 + Alignment:
Left + Aligned  at:  0.44" + Tab after:   0.84" + Indent  at: 
0.84",  Tab stops:   0.44",  List tab + Not at  0.84" 
8 
 2.622.65 Wood failure (percent)  
The area of wood fiber remaining at the bond line following completion of the specified shear 
test.  Determination is by means of visual examination and expressed as a percent of the test 
area.  
2.632.66 Working Face  
A face and/or back of a plywood panel that has an overlay system that meets a defined MDO or 
HDO grade (see section 5.6.7).  
3    REFERENCE PUBLICATIONS 1 
 
ASTM E  661-03 (2015)  Test Method for Performance of Wood and Wood -Based Floor and Roof 
Sheathing Under Concentrated Static and Impact Loads.  
 
ASTM D  2555 -06 17 Test Methods for Establishing Clear Wood Strength Values.  
 
ASTM D  2718 -00 18(2006)  Test Method for Structural Panels in Planar Shear (Rolling Shear).  
 
ASTM D  2719 -89 13(2007)  Test Methods for Structural Panels in Shear Through -the-Thickness.  
 
ASTM D  2915 -1703  Standard Practice for Evaluating Allowable Properties for Grades of 
Structural Lumber.  
 
ASTM D  3043 -1700 (2006)  Methods of Testing Structural Panels in Flexure.  
 
ASTM D  5266 -1399 (2005)  Standard Practice for Estimating the Percentage of Wood Failure in 
Adhesive Bonded Joints  
 
ASTM D906 -98 (2017 ) Standard Test Method for Strength Properties of Adhesives in Plywood 
Type Construction in Shear by Tension Loading  
 
International Building Code®  (IBC) . International Code Council. Country Club Hills, I L.  
 
International Residential Code® for One - and Two -Family Dwellings  (IRC) . International Code 
Council. Country Club Hills, IL.  
 
 
PS 2 -04 18  Performance Standard for Wood -Based  Structural -Use Panels.  
 
 
ISO/IEC 17020, Conformity Assessment – Requirements for the Operation of Various Types of Bodies 
Performing Inspection  
 
 
ISO/IEC 17025, General Requirements for the Competence of Testing and Calibration Laboratories  
 
 
ISO/IEC 17065, Conformity Assessment  – Requirements for bodies certifying products, processes and 
services  
                                                 
1 Copies of the ASTM publications are available from ASTM International, 100 Barr Harbor Drive, PO Box 
C700, West Conshohocken, PA  19428 -2959, www.astm.org.   
9 
  
4   PLYWOOD CLASSIFICATION  
4.1 General  
The plywood covered by this Standard is classified by bond classification and by grade.  
4.2 Bond classification  
The plywood covered by this Standard is classified as either Exposure 1 or Exterior.  Each 
classification is a function of veneer grade and adhesive performance. The bond classification is 
related to the moisture resistance of the adhesive bond under intended end -use conditions and 
does not rela te to the physical (erosion, ultraviolet, etc.) or biological (mold, fungal decay, 
insect, etc.) resistance of the panel.  
4.2.1  Exposure 1 plywood  
Plywood suitable for uses not permanently exposed to the weather.  Panels classified as 
Exposure 1 are intended to resist the effects of moisture on structural performance as may 
occur due to construction delays, or other conditions of similar severity.  Adhesive performance 
requirements for Exposure 1 plywood are provided in Section 5.7.1.  
 
Note:  Exposure 1 was formerly identified as Interior with Exterior Glue .  
4.2.2  Exterior plywood  
Plywood suitable for repeated wetting and redrying or long -term exposure to weather or other 
conditions of similar severity.  Adhesive performance requirements for Exterior plywood are 
provided in Section 5.7.2.  
4.3 Grade  
Within each bond classification, there  are a number of panel grades based on the grade of the 
veneers and the panel construction.  (See Table 2 for Exposure 1 grades and Table 3 for 
Exterior grades.)  
5    REQUIREMENTS  
5.1 General  
All plywood panels represented as conforming to this Standard shall meet or exceed all 
applicable requirements set forth herein.  Test methods are given in Section 6.  All terms shall 
be as defined in Section 2.  Requirements for trademarking and certification shall be as 
provided in Section 7.  
5.2 Wood species  
5.2.1  Species groups  
For the purpose of this Standard, species shall be any softwood or hardwood species or trade 
groups listed in Table 1 and other species meeting the requirements of Sections 5.2.3 or 5.2.4.  
For species grouping purposes, species listed in Table 1 but grow n in a different geographic 
region shall be evaluated in accordance with Appendix A.  For inclusion in Table 1, unlisted 
species shall be evaluated in accordance with Appendix A.  
5.2.1.1  Species segregation  
Species which cannot be distinguished in veneer form fro m similar species shall be classed as 
the largest numbered species group applicable (Group 4 is larger numbered than Group 1)  
10 
 unless the manufacturer provides valid evidence to the qualified inspection and testing agency 
that the species are properly segre gated.  Such segregation shall be in the form of separation 
prior to peeling, mechanical testing for performance capability, or other means approved by the 
qualified inspection and testing agency.  
5.2.2  Species for faces and backs  
Unless evaluated in accordance with Section 5.2.4, the species of face and back plies shall be 
from any group listed in Table 1.  When a face or back is made of more than one piece, the 
entire ply shall be of the same species.  When outer layers consist of two or more plies, the 
outer or exposed plies are classified as faces (face plies) or backs (back plies) and the 
unexposed plies (sub -faces and sub -backs) are classified as inner plies, in terms of species 
requirements as provided in Section 5.2.3.  Requirements for identifi cation of all panels are 
given in Section 7.3.  
   
11 
 TABLE 1.  CLASSIFICATION OF SPECIES(a) 
 
Group 1  Group 2  Group 3  Group 4  Group 5  
North American Species – Applicable to trees grown in North America   
Beech, American  Cedar, Port Orford  Pine Alder, Red  Aspen  Basswood  
Birch  Cypress   Pond  Birch, Paper   Bigtooth  Poplar, Balsam  
 Sweet  Douglas -fir (b)   Red Cedar, Alaska   Quaking   
 Yellow  Fir  Virginia  Fir, Subalpine  Cedar   
Douglas -fir (b)  Balsam   Western White  Hemlock, Eastern   Incense   
Larch, Western   California Red  Spruce  Maple, Bigleaf   Western Red   
Maple, Sugar   Grand   Black  Pine Cottonwood   
Pine, Southern   Noble   Red  Jack  Eastern   
 Loblolly   Pacific Silver   Sitka   Lodgepole   Black (W. Poplar)   
 Longleaf   White  Sweetgum   Ponderosa  Pine  
 Shortleaf  Hemlock, Western  Tamarack   Spruce   Eastern White   
 Slash  Maple, Black  Yellow Poplar  Redwood   Sugar   
Tanoak    Spruce    
    Engelmann    
    White    
Non North American Species   
Apitong(c)(d) Lauan  Mengkulang(c)   Cativo   
Kapur(c)  Almon  Meranti, Red(c)(e)     
Keruing(c)(d)  Bagtikan  Mersawa(c)    
Pine  Mayapis      
 Caribbean   Red Lauan      
 Ocote   Tangile      
  White Lauan      
(a) Table 1 species classified in accordance with ASTM D 2555 as discussed in Appendix A.  The species groupings are only 
valid for species grown in the regi ons referenced in Appendix A.  ( See Section 5.2.1 .) 
(b) Douglas -fir from trees grown in the states of Washington, Oregon, California, Idaho, Montana, Wyoming, and the 
Canadian Provinces of Alberta and British Columbia shall be  classed as Group 1 Douglas -fir.  Douglas -fir from trees 
grown in the states of Nevada, Utah, Colorado, Arizona and New Mexico shall be  classed as Group 2 Douglas -fir. 
(c) Each of  these names represents a trade group of woods consisting of a number of closely related species.  
(d) Species from the genus Dipterocarpus marketed collectively:  Apitong if originating in the Philippines, Keruing if 
originating in Malaysia or Indonesia.  
(e) Red Meranti shall be limited to species having a specific gravity of 0.41 or more based on green volume and oven dry 
weight.  
5.2.3  Species for inner plies  
5.2.3.1  Inner ply species group  
Unless otherwise permitted in Section 5.2.3.2 or 5.2.4, inner plies of Group s 1, 2, 3 or 4 panels 
shall be of any species listed in Groups 1, 2, 3 or 4 in Table 1.  Inner plies of Group 5 panels are 
permitted to be any species listed in Table 1.  
5.2.3.2  Inner ply specific gravity  
Inner plies of all panels shall also be permitted to be of any softwood species or any hardwood 
species having a published average specific gravity value of 0.41 or more based on green 
volume and oven dry weight.  The U.S. Forest Products Laboratory shall be considered as final 
evaluator of published specific g ravity data.  
5.2.4  Species classified by testing  
Species not listed in Table 1 or otherwise not covered by the provisions of Section 5.2 shall be 
qualified for use by panel performance testing in accordance with Section 5.8.6 for span -rated 
panels or with Secti on 5.8.7 for other panels except concrete form, Marine and Structural  I 
grades.  For panel marking purposes, re -classification of Group designation for species listed in 
Table 1 by panel performance testing in accordance with Section 5.8.7 is permitted.   
12 
 5.3 Synthetic repairs  
5.3.1  Synthetic fillers  
Use of synthetic fillers shall be limited to the repair of minor characteristics as specified.  
Synthetic fillers shall be approved by the qualified testing and inspection agency.  
5.3.2  Synthetic shims, patches, and plugs  
These repairs shall completely fill kerfs or voids; shall present a smooth, level surface; and shall 
not crack, shrink, or lose their bond.  Performance of synthetic shims, patches, and plugs under 
normal conditions of service shall be comparable to that of wood  repairs.  The equivalency shall 
be established by the qualified testing and inspection agency.  
5.4 Grade description of veneers  
All veneers in the finished plywood panel shall conform to one of the grade requirements listed 
in Sections 5.4.1 through 5.4.6.  Unless otherwise stated, these requirements apply to 1220  mm 
by 2440 mm (48 x 96 in) panels and are proportionate for other sizes.  Grade N is the highest 
classification.  For grading purposes, depressions (see Section 2. 18) shall be considered as 
rough gra in. 
5.4.1  Grade N veneer (intended for natural finish)  
5.4.1.1  General  
Grade N veneer shall be smoothly cut 100% heartwood or 100% sapwood, free from knots, 
knotholes, pitch pockets, open splits, other open characteristics, and stain.  The veneer shall 
consist of not mo re than two pieces in 1220 mm (48 in) widths and not more than three pieces 
in wider panels, and shall be well matched for color and grain.  When sanding is required (see 
Tables 2 and 3) p anels shall be sanded and shall permit no sander skips.  
 
Synthetic fillers shall be permitted to fill:  
 
(a) Small cracks or checks not more than 0.8 mm (1/32 in) wide.  
 
(b) Small splits or openings up to 1.6 mm (1/16 in) wide if not exceeding 50.8 mm 
(2 in) in length.  
 
(c) Small chipped areas or openings not more than 3.2 m m wide by 6.4 mm long 
(1/8 inch x 1/4  inch).  
5.4.1.2  Growth characteristics  
Where pitch streaks occur, each shall average not more than 9.5 mm (3/8 in) in width and shall 
blend with the color of the wood.  
5.4.1.3  Repairs  
Repairs shall be of wood, neatly made, and paralle l to grain.  They shall be limited to a total of 
six in number and be well matched for color and grain.  
 
Patches shall be limited to three "router" patches not exceeding 25.4 mm (1 in) in width and 
88.9 mm (3 -1/2 in) in length.  There shall be no overlappi ng. 
 
Shims shall not exceed 4.8 mm (3/16 in) in width or 305 mm (12 in) in length and shall occur 
only at the ends of the panel.   
13 
 5.4.2  Grade A veneer (suitable for painting)  
5.4.2.1  General  
Grade A veneer shall be firm, smoothly cut, and free of knots, pitch pockets, open splits, and 
other open characteristics and well joined when of more than one piece.  When sanding is 
required (see Tables 2 and 3) p anels shall be sanded and shall permit no sander skips.  
 
Synthetic fillers shall only be used to fill:  
 
(a)  In Exterior panels: small cracks or checks not more than 0.8 mm (1/32 in) wide; 
small splits or openings up to 1.6 mm (1/16 in) wide, if not exceeding 50.8 mm (2 
in) in length; small chipped areas or openings not more than 3.2 mm (1/8 in) wide 
by 6.4  mm (1/4  in) long.  
 
(b) In Exposure 1 panels: small cracks or checks not more than 4.8 mm (3/16 in) 
wide; openings or depressions up to 12.7 mm (1/2 in) wide by 50.8 mm (2 in) 
long or equivalent area.  
5.4.2.2  Growth characteristics  
Where pitch streaks occur, each shall av erage not more than 9.5 mm (3/8 in) in width and shall 
blend with the color of the wood.  Sapwood and discolorations to any degree shall be permitted.  
5.4.2.3  Repairs  
Repairs shall be of wood or synthetic patching material, neatly made, parallel to grain and 
limited to a total of 18 in number, excluding shims.  
5.4.2.4  Patches  
Patches, when of wood, shall be "boat,"  “compound boat,”  "router," or "sled" type.  The radius of 
ends of boat patches and compound boat patches shall not exceed 3.2 mm (1/8 in). 9.5 mm 
(3/8 in).  
 
A single wood patch shall be no larger than 57.2 mm x 114 mm (2 -1/4 in x 4 -1/2 in).  
 
Multiple wood repairs shall consist of not more than two patches, neither of which shall exceed 
178 mm (7 in) in length if either is wider than 25.4 mm (1 in), except that one multiple repair 
consisting of three die -cut veneer patches shall be permitted.  
 
For a multiple repair consisting of three patches across the width of the panel, the repaired area 
shall not exceed a width and length of 152 mm x 114 mm (6 in x 4-1/2 in)  
 
For a multiple repair consisting of three patches along the length of the panel, the repaired area 
shall not exceed a width and length of 57.2 mm x 267 mm (2 -1/4 in x 10 -1/2 in)  
 
Synthetic repairs are limited to the same repair areas as wood patches and shall be counted as 
one, two or three patches depending on the area repaired.  
 
The repair of a split having a width not greater than 31.8 mm (1 -1/4 in) and any length shall be 
cons idered one patch.  
 
Shims shall not be used over or around patches or as multiple repairs.   
14 
 5.4.3  Grade B veneer  
5.4.3.1  General  
Grade B veneer shall be solid and free from open characteristics and broken grain, except as 
permitted in Sections 5.4.3.1 through 5.4.3.4. Sli ghtly rough grain shall be permitted.  
 
Minor sanding and patching characteristics, including sander skips, shall not exceed 5% of 
panel area.  See Tables 2 and 3 for sanding requirements.  
 
Synthetic fillers shall only be used to fill:  
 
(a) In Exterior panel s:  small splits or openings up to 1.6 mm (1/16 in) wide if not 
exceeding 50.8 mm (2 in) in length; small chipped areas or openings not more 
than 3.2 mm wide by 6.4 mm long (1/8  in x 1/4 in).  
 
(b) In Exposure 1 panels:  small cracks or checks not more than  4.8 mm (3/16 in) 
wide; openings or depressions up to 12.7 mm wide by 50.8 mm long (1/2 in x 2 
in) or equivalent area.  
5.4.3.2  Growth characteristics  
Knots shall not exceed 25.4 mm (1 in) measured across the grain and shall be both sound and 
tight.  
 
Where pitch st reaks occur, they shall average not more than 25.4 mm (1 in) in width.  
 
Discolorations to any degree shall be permitted.  
5.4.3.3  Open characteristics  
Splits shall not be wider than 0.8 mm (1/32 in).  
 
Vertical borer holes shall not exceed 1.6 mm (1/16 in) in diameter and shall not exceed an 
average of one per 929 cm2 (1 ft2) in number.  
 
Horizontal or surface worm and borer holes shall be limited to 1.6 mm (1/16 in) across, 
25.4 mm (1 in) in length, and to 12 in number.  
5.4.3.4  Repairs  
Repairs shall be of wood or synth etic patching material and neatly made.  
 
Wood veneer repairs shall be die cut.  Wood panel repairs shall be "router" or "sled" type.  
 
Wood repairs shall not exceed 76.2 mm (3 in) in width where occurring in multiple repairs, or 
102 mm (4 in) in width where  occurring singly.  
Synthetic veneer repairs shall not exceed 102 mm (4 in) in width.  
 
Synthetic panel repairs shall not exceed 57.2 mm (2 -1/4 in) in width by any length, except that 
repaired areas not exceeding 152 mm in width by 114 mm in length (6 in x 4 -1/2 in) shall be 
allowed.  
 
Shims shall be permitted without limit.   
15 
 5.4.4  Grade C veneer  
5.4.4.1  General  
Sanding characteristics shall not impair the strength or serviceability of the panel.  See Tables 2 
and 3 for sanding requirements.  
5.4.4.2  Growth characteristics  
Knots shall be tight and not more than 38.1 mm (1 -1/2 in) across the grain.  
 
Discolorations to any degree shall be permitted.  
5.4.4.3   Open characteristics  
Any number of knotholes up to 25.4 mm ( 1 in) shall be permitted.  However, an occasional 
knothole more than 25.4 mm (1 in) but not more than 38.1 mm (1 -1/2 in) measured across the 
grain shall be permitted subject to the following provision:  
 
(a) Determine the Critical Section containing the knothol e.  (See Section 2.14.)  
 
(b) Determine the aggregate width of all knots and knotholes occurring wholly within 
the Critical Section.  Other open characteristics and growth characteristics are 
not included in this aggregate.  
 
(c) The knothole is permitted if  the aggregate width of all knots and knotholes in the 
Critical Section does not exceed 152 mm (6 in) in a 1220 mm (48 in) wide panel 
and proportionately for other panel widths.  
 
Splits measured at a point 203 mm (8 in) from the end of the panel shall not exceed 12.7  mm 
(1/2 in) in width by 1/2 panel length or 9.5 mm (3/8 in) in width by any panel length, provided 
separation at one end does not exceed 1.6 mm (1/16 in) where split runs full panel length; 
however, the maximum width within 203 mm (8 in) of the  end of the panel (open end of split) 
shall not exceed the maximum width of knotholes permitted within the grade.  
 
Splits on panel faces and backs shall not exceed 6.4 mm (1/4 in) where located within 
25.4 mm (1 in) of parallel panel edge.  
 
Voids due to mi ssing wood on panel faces and backs not otherwise specified above shall not 
exceed the maximum width of knotholes permitted in the grade and the length of such voids 
shall not exceed 152 mm (6 in).  
 
Wane not exceeding 203 mm (8 in) in length and the width permitted for open characteristics 
shall be allowed, providing that where wane occurs at edges of veneer sheets, panel ply 
separation due to wane shall not exceed the limit equivalent to that permitt ed for short and 
narrow inner plies in Section 5.8.3 for sanded panels, or Section 5.8.4 for unsanded or touch -
sanded panels.  
5.4.4.4  Repairs  
Repairs shall be wood or synthetic patching material, neatly made.  
 
Wood veneer repairs shall be die cut.  Wood panel repa irs shall be "router" or "sled" type.  
 
Wood repairs shall not exceed 76.2 mm (3 in) in width where occurring in multiple repairs, or 
102 mm (4 in) in width where occurring singly.   
16 
  
Synthetic veneer repairs shall not exceed 102 mm (4 in) in width.  
 
Syntheti c panel repairs shall not exceed 57.2 mm (2 -1/4 in) in width.  
 
Shims shall be permitted without limit.  
5.4.5  Grade C plugged veneer  
Knotholes, worm and borer holes, and other open characteristics not larger than 6.4 mm  (1/4 in) 
by 12.7 mm (1/2 in); sound and tig ht knots up to 38.1 mm (1 -1/2 in) measured across the grain; 
splits up to 3.2 mm (1/8 in) wide; broken grain; pitch pockets, if solid and tight; plugs; patches 
and shims shall be permitted.  Synthetic repairs in veneer shall not exceed 102 mm (4 in) in 
width.  Synthetic panel repairs shall not exceed 57.2 mm (2 -1/4 in) in width by any length, 
except that repaired areas not exceeding 152 mm (6 in) in width by 114 mm (4 -1/2 in) in length 
shall be allowed.  See Tables 2 and 3 for sanding requirements. Where gr ades having C 
Plugged face veneer are identified as fully sanded, sanding characteristics shall be the same as 
admitted under B grade.  Sander skips to any degree shall be admissible in touch -sanded C 
Plugged veneer.  
5.4.6  Grade D veneer  
5.4.6.1  General  
Except as otherw ise required in Sections 5.4.6.2 through 5.4.6.4, any number of plugs, patches, 
shims, worm or borer holes, sanding characteristics, and other characteristics shall be 
permitted, provided they do not seriously impair the strength or serviceability of the p anels.  
5.4.6.2  Growth characteristics  
Tight knots in inner plies shall be permitted.  
 
In D grade faces or backs, any number of tight knots not larger than 63.5 mm (2 -1/2 in) across 
the grain shall be permitted.  However, an occasional tight knot larger than 63.5 mm  (2-1/2 in) 
but not larger than 76.2 mm (3 in) measured across the grain, shall be permitted subject to the 
following provision:  
 
(a) Determine the Critical Section containing the knot.   (See Section 2.14.)  
 
(b) Determine the aggregate width of all kno ts and knotholes occurring wholly within 
the Critical Section.  Other open characteristics and growth characteristics are 
not included in this aggregate.  
 
(c) The knot is permitted if the aggregate width of all knots and knotholes in the 
Critical Section d oes not exceed 254 mm (10 in) in a 1220 mm (48 in) wide panel 
and proportionately for other panel widths.  
5.4.6.3  Open characteristics  
Any number of knotholes up to 63.5 mm (2 -1/2 in) across the grain shall be permitted. However, 
an occasional knothole larger than  63.5 mm (2 -1/2 in) but not larger than 76.2  mm (3 in) 
measured across the grain shall be permitted subject to the following provision:  
 
(a) Determine the Critical Section containing the knothole.   (See Section 2.14.)  
  
17 
 (b) Determine the aggregate width of all knots and knotholes occurring wholly within 
the Critical Section.  Other open characteristics and growth characteristics are 
not included in this aggregate.  
 
(c) The knothole is permitted if the aggregate width of all knots and knotholes in the 
Critical Se ction does not exceed 254 mm (10 in) in a 1220 mm (48 in) wide panel 
and proportionately for other panel widths.  
 
Knotholes in sanded panels shall not exceed 63.5 mm (2 -1/2 in) across the grain in veneer 
thicker than 3.2 mm (1/8 in).  
 
Knotholes shall not exceed 88.9 mm (3 -1/2 in) across the grain in veneers at least two plies 
removed from the face or back plies of C -D, D-D and C -D Plugged grades having five or more 
plies.  
 
Splits measured at a point 203 mm (8 in) from the end of the panel shall not exc eed 
25.4 mm (1 in) in width, tapering to not more than 1.6 mm (1/16 in) where split runs full panel 
length; however, the maximum width within 203 mm (8 in) of the end of the panel (open end of 
split) shall not exceed the maximum width of knotholes permitte d within the grade.  
 
Splits on panel faces and backs shall not exceed 6.4 mm (1/4 in) in width where located within 
25.4 mm (1 in) of parallel panel edge.  
 
Voids due to missing wood on panel backs not otherwise specified in Section 5.4.6.3 shall not 
exceed  the maximum width of knotholes permitted in the grade and the length of such voids 
shall not exceed 152 mm (6 in).  
 
Wane not exceeding 203 mm (8 in) in length and the width permitted for open characteristics is 
allowed, providing that where occurring at e dges of veneer sheets, panel ply separation due to 
wane shall not exceed the limit equivalent to that permitted for short and narrow inner plies in 
Section 5.8.3 for sanded panels, or Section 5.8.4 for unsanded or touch -sanded panels.  
5.4.6.4  White pocket  
Any area  610 mm (24 in) wide across the grain and 305 mm (12 in) long, in which light or heavy 
white pocket occurs, shall contain not more than three of the following characteristics, in any 
combination:  
 
(a) A 152 mm (6 in) width of heavy white pocket.  
 
(b) A 305  mm (12 in) width of light white pocket.  
 
(c) One knot or knothole, 38.1 mm (1 -1/2 in) to 63.5 mm (2 -1/2 in), or two knots or 
knotholes, 25.4 mm (1 in) to 38.1 mm (1 -1/2 in). Knots or knotholes less than 
25.4 mm (1  in) shall not be considered.  Sizes of an y knot or knothole shall be 
measured across the grain.  Any repair in a white pocket area shall be 
considered for grading purposes as a knothole.  
5.5 Veneers and layers  
5.5.1  Veneer thickness  
Except as provided for in the following paragraphs, veneer shall be 2.5 mm (1/10 in) or thicker in 
panels with Performance Category of 3/8 rough (unsanded) thickness or over; 2.1 mm (1/12 in)  
18 
 or thicker in panels with Performance Category of less than 3/8  rough (unsanded) thickness.  In 
no case shall veneers used in face or back layers be thicker than 6.4 mm (1/4 in), or veneers 
used in inner layers be thicker than 7.9 mm (5/16 in).  
 
Veneer of 2.1 mm (1/12 in) shall be permitted as crossbands in 5 -ply, 5 -layer panels with 
Performance Category of 15/32   and 1/2   and in parallel -laminated layers as provided for in 
5.5.2.  
 
Veneer of 1.6 mm (1/16 in) shall be permitted for any ply in 5 -ply Exterior type panels with 
Performance Category of less than 15/32 ; as t he center only in other 5 -ply panels; and in a 
parallel laminated layer as provided for in Section 5.5.2.  
 
Face and back veneers shall be a minimum thickness of 3.2 mm (1/8 in) for panels with 
Performance Category of 19/32  5/8 , 3, 4, and 5 -ply, 3 -layer pa nels of C -D, C-D Plugged, C -C, 
C-C Plugged and Underlayment grades.  
 
Further limitations on panel layup are provided in Section 5.8, Panel Constructions and 
Workmanship.  
 
The average veneer thickness shall conform to the limitations given in this Standard within a 
tolerance of  5% of the specified nominal thickness measured dry before layup.  
 
In lieu of veneer thickness requirements above, panels qualifying under workmanship provisions 
of Section 5.8 and performance testing in accord ance with Section 5.8.6 or 5.8.7 shall be 
permitted.  
5.5.2  Parallel laminated layers  
Parallel -laminated outer layers shall only be used in C -C, C-D, D-D and Structural I C -C and 
C-D grades.  Such layers shall consist of veneers 2.5 mm (1/10 in) or thicker in any  combination 
not exceeding 6.4 mm (1/4 in) total layer thickness.  The face and back plies or exposed plies of 
outer layers shall conform to the species group and grade requirements for faces and backs, 
respectively, of the panel grade.  The unexposed plie s of outer layers, or sub -face and sub -back 
plies, shall conform to the species group and grade requirements for inner plies of the panel 
grade as specified in Tables 2 and 3 and Section 5.6.5.  The maximum split or gap in sub -faces 
and sub -backs shall be 6.4 mm (1/4 in) under the faces of Structural I C -C and C -D panels; 
12.7 mm (1/2 in) under the faces of C -C, C-D and D -D grades, and 12.7 mm (1/2 in) under D 
backs.  
 
Parallel -laminated inner layers in any grade shall consist of veneers 1.6 mm (1/16 in) or thicker 
in any thickness combination not exceeding 11.1 mm (7/16 in) total layer thickness.  Individual 
plies in such layers shall conform to the species group and grade requirements for inner plies of 
the panel grade.  
In lieu of veneer thickness requireme nts above, panels qualifying under workmanship provisions 
of Section 5.8 and performance testing in accordance with Section 5.8.6 or Section 5.8.7 shall 
be permitted.  
 
   
19 
 TABLE 2.  EXPOSURE 1 PLYWOOD GRADES (PERMITS D GRADE VENEER)  
 
 Minimum Veneer Quality   
Panel Grade Designations  Face  Back  Inner Plies  Surface  
N-N N N C Sanded 2 sides  
N-A N A C Sanded 2 sides  
N-B N B C Sanded 2 sides  
N-D N D D Sanded 2 sides  
A-A A A D Sanded 2 sides  
A-B A B D Sanded 2 sides  
A-D A D D Sanded 2 sides  
B-B B B D Sanded 2 sides  
B-D B D D Sanded 2 sides  
Underlayment(a) C Plugged  D C & D  Touch -sanded  
C-D Plugged  C Plugged  D D Touch -sanded  
Structural I C -D  See 5.6.5   Unsanded(b) 
Structural I C -D Plugged, Underlayment   See 5.6.5   Touch -sanded  
C-D C D D Unsanded(b) 
D-D(c) D D D Unsanded(b) 
     
(a) See Section 5.6.3 and Table 5 for special limitations.  
(b) See Section 5.8.4 for requirements.  
(c) Applicable only to panels qualified through performance testing per Section 5.8.6 (plus Section 6.2.2.3 of PS 2 -
0418) or PS 2 -0418. 
5.5.3  Scarfed veneers  
Scarfed veneers shall be permitted for any face, back, or inner ply except as provided in 
Section  5.9.  Sca rfed joints shall not have a slope steeper than 1 to 8.  Veneer in the scarf area 
shall not contain characteristics which reduce its effective cross section by more than 20%.  
Veneer scarfed joints shall be bonded with a moisture resistant adhesive.  
5.6 Panel grades  
The standard combination of the veneers described in Section 5.4 assembled into the various 
panel grades shall be as provided in Tables 2 and 3, with the additional requirements provided 
in Sections 5.6.1 through 5.6.7.  The grain direction of the o uter layers shall be either parallel or 
perpendicular to the long dimension of the panel.  
   
20 
 TABLE 3.  EXTERIOR PLYWOOD GRADES(a) (DOES NOT PERMIT D GRADE VENEER)  
 
 Minimum Veneer Quality   
Panel Grade Designations  Face  Back  Inner 
Plies  Surface  
Marine (A -A, A-B, B-B, HDO, MDO)   See 5.6.1   See regular grades  
Special Exterior (A -A, A-B, B-B, HDO, MDO)   See 5.6.6   See regular grades  
A-A A A C Sanded 2 sides  
A-B A B C Sanded 2 sides  
A-C A C C Sanded 2 sides  
B-B (concrete form)  B B C See 5.6.4  
B-C (concrete form)  B C C See 5.6.4  
B-B B B C Sanded 2 sides  
B-C B C C Sanded 2 sides  
C-C Plugged(b) C Plugged  C C Touch -sanded  
C-C C C C Unsanded(c) 
HDO -Industrial A -A, B-B, B-C       C (d)  
HDO -Concrete Form(e)  A-A, B-B, B-C   C  
MDO -General B -B, B-C   C  
MDO -Concrete Form(e) B-B, B-C   C  
Special Overlays  C C C — 
(a) Available also in Structural I classification as provided in Section 5.6.5.  
(b) See Section 5.6.3 and Table 5 for special limitations.  
(c) See Section 5.8.4 for requirements.  
(d) C Plugged for HDO -Industrial when intended for sign applications  
(e) For more clarification on concrete form grades, see Section 5.6.4.  
5.6.1  Marine  
Marine gr ades shall meet the requirements of Exterior plywood and shall be of one of the 
following grades:  A -A, A-B, B-B, High Density Overlay, or Medium Density Overlay, all as 
modified in Sections 5.6.1.1 through 5.6.1.3.  
5.6.1.1  Species  
Only Group 1 Douglas -fir and Wes tern Larch veneers shall be used.  
5.6.1.2  Veneers  
Grade A faces shall be limited to a total of nine single wood repairs in a 1220 mm by 2440  mm 
(48 x 96 in) sheet, or to a proportionate number in any other size as manufactured.  
 
All inner plies shall be B grade o r better and shall be full length and width.  
 
All wood repairs shall be bonded with an adhesive meeting the Exterior performance 
requirements of Section 5.7.2 and, in addition, shall be set in the panel using a technique 
involving both heat and pressure.  
 
When the inner plies consist of two or more pieces of veneer, the edges shall be straight and 
square, and shall not overlap.  
5.6.1.3  Crossband gaps and edge splits  
Neither edge of a panel shall have any crossband gap or edge split in excess of 3.2  mm (1/8 in) 
wide.  Crossband gaps and edge splits per 2440 mm (96 in) of crossband ply shall not exceed 
four in number.  End splits and gaps on either end of a panel shall not exceed 3.2  mm (1/8 in) in 
aggregate width.  
 
There shall be no filling of crossband gaps and edge  splits.   
21 
 5.6.2  Decorative panels  
Specialty panels with decorative face and veneer treatments which, except for the special face 
treatment, meet all of the requirements of this Standard, including veneer qualities, adhesive 
bond performance and workmanship, shall  be considered as conforming to this Standard.  All 
grades in Tables 2 and 3 shall be permitted to be manufactured as decorative grades.  
 
An occasional butt joint used for decorative effect in veneer shall have a maximum width of 
152 mm (6 inches) and shal l be limited to one panel face.  Where butt joints occur, the 
aggregate width of all knots and knotholes and two -thirds the aggregate width of all repairs, 
including butt joints, shall not exceed 152 mm (6 in) in any area 305 mm (12 in) along the grain 
by 1220 mm (48 in) wide or proportionately for other widths.  
5.6.3  Underlayment  
Underlayment is plywood produced with touch sanded faces is appropriate for floor applications 
using carpet and pad. to the following requirements.  
 
5.6.3.1 Exposure 1 underlayment Underlayment .   
Face veneer shall be C -plugged grade 2.5 mm (1/10  in) or thicker before sanding.  The veneer 
immediately adjacent to the face ply shall be C grade or better with no open characteristics over 
25.4 mm (1 in) acr oss the grain; except that veneer immediately adjacent to the face ply shall be 
permitted to be D grade with open characteristics up to 63.5 mm (2 -1/2 in) across the grain 
provided the face veneer is of Group 1 or 2 species of 4.2 mm (1/6 in) minimum thick ness 
before sanding.  Also see Table 5 requirements.  
 
5.6.3.2 Exterior underlayment Underlayment (C-C plugged or better) .   
Face veneer shall be C -plugged grade or better 2.5 mm (1/10 in) or thicker before sanding.  The 
veneer immediately adjacent to the face ply shall be C grade or better with no open 
characteristics over 25.4 mm (1  in) across the grain except that veneer immediately adjacent to 
the face ply shall be permitted to be C grade with open characteristics up to 38.1 mm (1 -1/2 in) 
across the gra in, provided the face veneer is of Group 1 or 2 species of 4.2 mm (1/6 in) 
minimum thickness before sanding.  Also see Table 5 requirements.  
5.6.4  Concrete form panels  
Face veneers shall not be less than B grade and back veneers shall not be less than C grade.  
The face and back veneers shall be of the same species group.  The face and back veneers 
shall be designated in the trademark.  Inner plies shall be not less than "C" grade.  This grade of 
plywood is produced in two classes, and panels of each class shall  be identified accordingly.  
Non-overlaid panels shall be sanded two sides and have a mill -applied release agent unless 
otherwise agreed upon between buyer and seller.  For non -overlaid panels, Western Larch shall 
be excluded from use in the face plies of concrete form plywood due to the excessive wood 
sugars that prohibit proper curing of concrete.  Species shall be further limited as follows and 
are applicable also to High Density Overlaid Exterior and Medium Density Overlaid Exterior 
concrete form panels : 
 
(a) Class I — Faces of Group 1 species, crossband of Group 1 or Group 2 species, 
and centers of Group 1, 2, 3, or 4 species.  
 
(b) Class II — Faces of Group 1 or Group 2 species, and crossband and centers of 
Group  1, 2, 3, or 4 species; or, faces of Group 3 species of 3.2 mm (1/8 in) 
minimum thickness before sanding, crossband of Group 1, 2, or 3 species, and 
centers of Group 1, 2, 3, or 4 species.   
22 
 5.6.5  Structural I panels  
These panels are especially designed for engineered applications such as structural 
components where design properties, including tension, compression, shear, cross -panel 
flexural properties and nail bearing are of significant importance.  Structural I shall be produced 
as C-D, C-D Plugged, Underlayment  or any Exterior  grade (see Table 3) . In addition to the 
special species, grade and adhesive bond requirements set forth in the tabulation below, 
Structural  I panels shall meet all other requirements in this Standard for the applicable types 
and grades  and the additional requirements below: . 
 
a. All face, back and inner plies shall be Group 1 species as listed in Table 1  
b. Special limitations applying to Structural I (C -D, C-D Plugged, Underlayment) grade 
panels are:  
• In D grade veneers, white pocket in any area larger than the size of the largest 
knothole,  pitch pocket or split specifically permitted in D grade shall not be 
permitted in any ply  
• Sound tight knots in D grade shall not exceed 63.5 mm (2 -1/2 in) measured 
across the grain, except as provided in Table 5  
• Plugs, including multiple repairs, shall not exceed 102 mm (4 in) in width.  
  
 
 
Grade  Bond Performance  Species  
 
Structural I(a) 
 C-D 
 C-D Plugged  
 Underlayment   
Shall meet the requirements of  
5.7.1 for Exposure 1   
Face, back and all inner plies  
limited to Group 1 species  
Structural I  
 All Exterior grades  
 (See Table 3)  Shall meet the requirements of 5.7.2 
for Exterior  Face, back and all inner plies  
limited to Group 1 species  
(a) Special limitations applying to Structural I (C -D, C-D Plugged, Underlayment) grade panels are:  
 — In D grade veneers, white pocket in any area larger than the size of the largest knothole,  
  pitch pocket or split specifically permitted in D grade shall not be permitted in any ply.  
 — Sound tight knots in D grade shall not exceed 63.5 mm (2-1/2 in) measured across the  
  grain, except as provided in Table 5.  
 — Plugs, including multiple repairs, shall not exceed 102 mm (4 in) in width.  
 — Panel construction shall be as specified in Section 5.8.   
5.6.6  Special Exterior  
An Exterior panel that is produced from any species covered by this Standard.  Except in regard 
to species, it shall meet all of the requirements for Marine panels (see Section 5.6.1) and be 
produced in one of the following grades:  A -A, A-B, B-B, High Density Overlay, or Medium 
Density Overlay.  
5.6.7  Overlays  
For overlaid plywood, the grade designation for face and back, as given in Table 3, refers to the 
veneer directly beneath the overlay.  All overlaid plywood shall be overlaid on two sides unless  
identified as having one working face as specified in section 7.3.c .  When only one side is 
overlaid (or when a backer sheet is applied), the back shall be C or better.  The surface of 
overlaid plywood shall be smooth, or uniformly textured, although some evidence of underlying 
grain shall be permitted.  Formatted:  List Paragraph,  Numbered  + Level:  1 +
Numbering  Style:  a, b, c, … + Start at: 1 + Alignment:  Left +
Aligned  at:  0.25" + Indent  at:  0.5"
Formatted:  Font: 11 pt
Formatted:  Bulleted  + Level:  2 + Aligned  at:  0.75" +
Indent  at:  1"
Formatted:  Font: 11 pt
Formatted:  Font: 11 pt
Formatted:  Bulleted  + Level:  2 + Aligned  at:  0.75" +
Indent  at:  1"
Formatted:  List Paragraph,  Numbered  + Level:  1 +
Numbering  Style:  a, b, c, … + Start at: 1 + Alignment:  Left +
Aligned  at:  0.25" + Indent  at:  0.5" 
23 
 5.6.7.1  High Density Overlay - Concrete Form  
HDO Concrete Form plywood shall be manufactured with thermosetting phenolic resin 
impregnated cellulose -fiber sheet or sheets bonded to the working face.  The overlay layer shall 
consist of a she et or sheets, containing not less than 52% phenolic resin content, based on the 
volatile -free weight of fiber and resin.  The thickness of resin -impregnated materials for each 
working face shall be not less than 0.30 mm (0.012 in) thick before pressing and  shall weigh not 
less than 290 g per m2 (60 pounds per 1000 ft2) in the ready -to-use condition.  When the overlay 
layer is composed of MDO cushion sheet and HDO cap sheet (or sheets), the MDO sheet shall 
be not less than 34% phenolic resin content based on  the volatile -free weight of resin and fiber, 
exclusive of bond line.  
5.6.7.2  High Density Overlay - Industrial  
HDO Industrial plywood is typically used for highway signs or industrial applications.  HDO -
Industrial plywood shall be manufactured with thermosetting phenolic resin impregnated 
cellulose -fiber sheet or sheets bonded to the working face.  The overlay layer shall consist of a 
sheet or sheets, containing not less than 45% phenolic resin content based on the volatile -free 
weight of fiber and resin.  The thi ckness of resin -impregnated materials for each working face 
shall be not less than 0.30 mm (0.012 in) thick before pressing and shall weigh not less than 
290 g per m2 (60 pounds per 1000 ft2) in the ready -to-use condition.  When the overlay layer is 
compos ed of MDO cushion sheet and HDO cap sheet (or sheets), the MDO sheet shall be not 
less than 34% resin content based on the volatile -free weight of resin and fiber, exclusive of 
bond line.  
5.6.7.3  Medium Density Overlay - Concrete Form  
MDO Concrete Form plywood shall be manufactured with thermosetting phenolic resin 
impregnated cellulose -fiber sheet or sheets bonded to the working face.  The overlay layer shall 
consist of a sheet or sheets, containing not less than 34% phenolic resin content based on the 
volatile -free weight of fiber and resin, but exclusive of bond line.  The thickness of resin -
impregnated materials for each working face shall be not less than 0.30 mm (0.012 in) thick 
after pressing and shall weigh not less than 280 g per m2 (58 pounds pe r 1000 ft2) including both 
resin and fiber, but exclusive of bond line.  Unless otherwise agreed upon between buyer and 
seller, MDO Concrete Form plywood shall be treated with a release agent.  
5.6.7.4  Medium Density Overlay – General  
MDO General plywood shall be m anufactured with thermosetting phenolic resin impregnated 
cellulose -fiber sheet or sheets bonded to the working face.  The overlay layer shall consist of a 
sheet or sheets, containing not less than 27% phenolic resin content based on the volatile -free 
weight of fiber and resin, but exclusive of bond line.  The thickness of resin -impregnated 
materials for each working face shall be not less than 0.30 mm (0.012 in) thick after pressing 
and shall weigh not less than 280 g per m2 (58 pounds per 1000 ft2) includ ing both resin and 
fiber, but exclusive of bond line.  The resin -treated facing on the finished product s hall be 
suitable for painting.  
5.6.7.5  Special overlays  
These are surfacing materials having resin systems, resin -treated fiber materials, or special 
character istics that do not fit the particular description of High Density or Medium Density 
overlays as given in Sections 5.6.7.1, 5.6.7.2, 5.6.7.3, or 5.6.7.4.  Special Overlays shall meet 
the adhesive bond requirements for overlaid plywood.  (See 5.7.2.2.)  Alth ough designed for a 
wide variety of uses, this overlaid plywood shall be Exterior, including the base panel, bond of 
overlay to the panel, and the overlay itself.  Panels shall be identified as "Special Overlay."   
24 
 5.7 Adhesive bond requirements for a panel or a  lot 
The adhesive bond shall meet the requirements below.  
5.7.1  Exposure 1  
A panel shall be considered as meeting Exposure 1 adhesive bond requirements of this 
Standard if the test specimens taken from a panel average 80% wood failure or greater when 
tested in a ccordance with Section 6.1.3 .  For qualification purposes, specimens from at least 20 
panels shall be sampled . 
 
Lots represented by test panels shall be considered as meeting the requirements of this 
Standard if the requirements of (a) and (b) are met:  
 
(a) The average wood failure of all test specimens, regardless of the number of 
panels tested, shall be not less than 80% , 
 
(b) And: 
 
 (1)  When at least 10 panels are tested, a t least 90% of the panels represented 
by the test pieces shall have 60% wood failure or better, and  
 
 (2)  When at least 20 panels are tested, at least 95% of the panels represented 
by the test pieces shall have 30% wood failure or better.  
 
 (3)  When fewer than 10 panels are tested, all panels represented by the test 
pieces shall have 60% wood failure or better.  
 
The requirements of Section 5.7.1 are applicable separately and independently to the results 
obtained from the vacuum -pressure test (Sec tion 6.1.3.2) and the boiling test (Section 6.1.3.3).  
Specimens cut through localized characteristics permitted in the grade shall be discarded.  Test 
specimens showing delamination in excess of 3.2 mm (1/8 in) deep and 25.4 mm (1 in) long 
shall be rated as zero (0)% wood failure.  
5.7.1.1  Heat performance  
Panels shall meet the heat performance requirements for Exterior adhesives.  (See Section 
5.7.2.1.)  
5.7.2  Exterior  
When tested in accordance with Section 6.1.3, Exterior plywood shall be considered as meeting 
the adhes ive bond requirements of this Standard if the test specimens taken from a panel 
average 85% wood failure or greater.   For qualification purposes, specimens from at least 20 
panels shall be sampled.  
 
Lots represented by test panels shall be considered as me eting the requirements of this 
Standard if the minimum requirements of (a) and (b) are met:  
 
(a) The average wood failure of all test specimens, regardless of the number of 
panels tested, shall be not less than 85 %, 
 
(b) And: 
 
(1) When at least 4 panels  are tested, a t least 75% of the panels represented 
by the test pieces shall have 80% wood failure or better;  and  
25 
  
(2) When at least 10 panels are tested, a t least 90% of the panels 
represented by the test pieces shall have 60% wood failure or better; and  
 
(3) When at least 20 panels are tested, a t least 95% of the panels 
represented by the test pieces shall have 30% wood failure or better.  
 
(4) When fewer than 4 panels are tested, all panels represented by the test 
pieces shall have 80% wood failure or better.  
 
The r equirements of Section 5.7.2 are applicable separately and independently to the results 
obtained from the vacuum -pressure test (Section 6.1.3.2) and the boiling test (Section 6.1.3.3).  
Specimens cut through localized characteristics permitted in the grade  shall be discarded.  Test 
specimens showing delamination in excess of 3.2 mm (1/8 in) deep and 25.4 mm (1 in) long 
shall be rated as zero (0)% wood failure.  
5.7.2.1  Heat performance  
Exterior plywood shall be considered as meeting the requirements of this section if there is no 
delamination in any specimen, except when occurring at a localized characteristic permitted in 
the grade when tested in accordance with Section 6.1.3.4.  When t esting overlaid plywood, 
blisters or bubbles in the surface caused by combustion shall not be considered as 
delamination.  
5.7.2.2  Overlaid plywood  
The bond between veneers of overlaid plywood as well as the bond between the overlay and 
the base panel shall meet t he wood failure requirements described in Section 5.7.2 for Exterior 
plywood.  In evaluating specimens for separation of the resin -treated face from the plywood, 
fiber failure shall be considered the same as wood failure.  
5.8 Panel constructions and workmansh ip 
Constructions for all panels shall conform to the minimum number of plies and layers as set 
forth in Table 4.  The proportion of wood with grain perpendicular to panel face grain shall be 
not less than 33% nor more than 70% of the total panel thickness.   The combined thickness of 
inner layers in panels having 4 or more plies shall be not less than 45% of the total panel 
thickness.  For application of these requirements, the panel thickness shall be the actual 
finished panel thickness and the veneer thick ness shall be the dry veneer thickness before 
layup.   
 
The grain of all layers shall be perpendicular to the grain of adjacent layers and to the ends or 
edges of the panel.  The entire area of each contacting surface of the adjacent plies, including 
repai rs, shall be bonded with an adhesive in a manner to assure compliance with the 
performance requirements for its type as set forth in the test described in Section 6.   
 
For the purpose of veneer repairing or edge joining, strings, ribbons, or tapes up to 9 .5 mm 
(3/8 in) maximum width can occur in a bond line and shall be considered as allowable localized 
characteristics in the evaluation of bond line test specimens.  Wider strings, ribbons, or tapes 
shall not be used for veneer repairing or joining unless t hey are pre -qualified to show bonding 
equal to the required bonding for the panel.  Bond line test specimens cut to include the strings, 
ribbons, or tapes wider than 9.5 mm (3/8 in) shall not be discarded because of the presence of 
these materials.  
 
Veneer strips shall not be joined by string stitching.   
26 
  
Rough or unsanded plywood shall be permitted to have paper tape on either face or back, or 
both; except that, in C -C Exterior, no tape used for veneer splicing shall be permitted.  
 
Shims or strips o f veneer shall not be used to repair panel edge voids.  However, filling of 
permissible edge voids with synthetic fillers neatly applied shall be allowed, except as prohibited 
in Marine grades.  (See Section 5.6.1.)  Staples or pins of metal or synthetic m aterial shall be 
prohibited.  
 
Where face or back plies consist of more than one piece of edge joined veneer, gaps between 
adjacent pieces shall be graded as splits.  
 
End butt joints shall only be used under the following conditions:  
 
(a) Decorative grad es as provided in Section 5.6.2.  
 
(b) Butt joints having a total aggregate width not exceeding the width of the panel 
shall occur in the center ply of 5 -ply, 5 -layer panels.  The butt joints shall be 
perpendicular to the grain of the panel face and back pl ies.  The use of butt -
jointed centers shall be allowed in Exposure 1 sanded grades in panels with 
Performance Category up to and including 1/2, and in D-D, C-D and C -D 
Plugged panels with Performance Category up to and including 3/4 .  End butt 
joints shal l not be used in Structural I panels.  Panels with butt joints in center 
plies shall be marked "butt -jointed center" as specified in Section 7.3.  
 
Plywood shall be free from blisters, laps and other characteristics, except as expressly 
permitted in Section  5.8 and its subsections.  Panels shall have no continuous holes or through 
openings from face to back.  
5.8.1  Crossband gaps and center gaps  
Crossband gaps or center gaps, except as noted for plugged crossband and jointed crossband, 
shall not exceed 25.4 mm (1 in) in width for a depth of 203 mm (8 in) measured from panel 
edge.  The average of all gaps occurring in a panel shall not exceed 12.7 mm (1/2 in).  Where 
inner layers are thicker than 6.4 mm (1/4 in), gaps in the laminated plies shall be offset 
25.4 mm (1 in) if over 6.4 mm (1/4 in) wide.  
 
Where plugged inner plies are specified, inner plies shall be of C Plugged veneer, and gaps 
between adjacent pieces of inner plies shall not exceed 12.7 mm (1/2 in).  
 
Where jointed inner plies are specified, gaps betw een pieces of inner plies shall not exceed 
9.5 mm (3/8 in), and the average of all gaps occurring in a panel shall not exceed 4.8  mm 
(3/16  in).  
   
27 
 TABLE 4.  PANEL CONSTRUCTIONS (MINIMUM NUMBER OF PLIES AND LAYERS)  
 
 
 
Panel Grades  Finished Panel  
Performance Category Range  Minimum  
Number  
of Plies  Minimum  
Number  
of Layers  
 
Exterior  
 Marine  
 Special Exterior (See 5.6.6 )  
 B-B Concrete form  
 B-C Concrete form  
 HDO Industrial A -A, B-B, B-C 
 HDO Concrete Form A -A, B-B, B-C 
 MDO Concrete Form B -B, B-C 
  
 
 
 
Through 3/8  
Over 3/8 , through 3/4  
Over 3/4   
 
 
 
3 
5 
7  
 
 
 
3 
5 
7 
 
Exposure 1  
 N-N, N-A, N-B, N-D, A-A, A-B, 
  A-D, B-B, B-D 
 Structural I (C -D, C-D Plugged  
  and Underlayment)  
 
Exterior  
 A-A, A-B, A-C, B-B, B-C 
 Structural I (C -C and  
  C-C Plugged) (See 5.6.5)  
 MDO General B -B, B-C 
 Special Overlays  
  
 
 
 
 
Through 3/8  
Over 3/8 , through 1/2  
Over 1/2 , through 7/8  
Over 7/8   
 
 
 
 
3 
4 
5 
6  
 
 
 
 
3 
3 
5 
5 
 
Exposure 1  
 Underlayment  
  
Exterior  
 C-C Plugged  
 
  
 
Through 1/2  
Over 1/2 , through 3/4 
Over 3/4   
 
3 
4 
5  
 
3 
3 
5 
 
Exposure 1  
 C-D 
 C-D Plugged  
 D-D 
 
Exterior  
 C-C 
  
 
 
Through 5/8  
Over 5/8 , through 3/4  
Over 3/4   
 
 
3 
4 
5  
 
 
3 
3 
5 
5.8.2  Veneer requirements  
The veneers used in each ply of each panel and the completed panel shall conform with the 
applicable veneer grade and with the construction and workmanship requirements given herein.  
Additionally, in recognition of the requirements of selected end uses, the type and frequency of 
specific characteristics s hall be further limited for grades in Table 5.  
 
  Formatted  Table 
28 
  
TABLE 5.  CHARACTERISTICS PROHIBITED OR RESTRICTED IN CERTAIN PANEL GRADES  
 
Panel Grade 
Designation   
Description and Number of Characteristics Per Panel  
N-N, N-A No crossband laps adjacent to faces and backs  
N-B No crossband laps adjacent to N faces  
No more than 2 crossband laps adjacent to B grade side (Section 5.8.3)  
Laps are limited to 4.8 mm (3/16 in)  
N-D No crossband laps adjacent to faces  
No more than a total of 2 of any combination of the following:  
 — Knothole in D veneer over 63.5 mm (2 -1/2 in) but not over 76.2 mm (3 in)  
  — Split in D veneer over 12.7 mm (1/2 in) but not over 25.4 mm (1 in)  
 — Crossband lap adjacent to backs  
Underlayment 
and C -C 
Plugged  No knotholes in veneer adjacent to face over 25.4 mm (1 in) across the grain where C grade is required per 
Tables 2 and 3  
No knotholes in veneer adjacent to face over 63.5 mm (2 -1/2 in) where D grade is permitted or over 38.1 mm 
(1-1/2 in) where C grade is pe rmitted per 5.6.3  
No laps adjacent to face  
Structural I C -D No splits in faces over 6.4 mm (1/4 in)  
No splits in backs over 12.7 mm (1/2 in)  
No more than a total of 2 of any combination of the following:  
 — Knothole in C veneer over 25.4 mm (1 in) but not over 38.1 mm (1 -1/2 in)  
 — Knot in D backs over 63.5 mm (2 -1/2 in) but not over 76.2 mm (3 in)  
 — Knothole in D veneer over 63.5 mm (2 -1/2 in) but not over 76.2 mm (3 in)  
 — Crossband lap adjacent to faces (See Section 5.8.4)  
 — Crossband lap adjacent to backs (See Section 5.8.4)  
Structural I C -D 
Plugged  No splits in backs over 12.7 mm (1/2 in)  
No more than a total of 2 of any combination of the following:  
 — Knot in D backs over 63.5 mm (2 -1/2 in) but not over 76.2 mm (3 in)  
 — Knothole in D veneer ov er 63.5 mm (2 -1/2 in.) but not over 76.2 mm (3 in)  
 — Crossband lap adjacent to faces (See Section 5.8.4)  
 — Crossband lap adjacent to backs (See Section 5.8.4)  
Structural I 
Underlayment  No knotholes in core veneer next to face over 25.4 mm (1 in)  
No crossband laps adjacent to faces  
No splits in backs over 12.7 mm (1/2 in)  
No more than a total of 2 of any combination of the following:  
 — Knot in D backs over 63.5 mm (2 -1/2 in) but not over 76.2 mm (3 in)  
 — Knothole in D veneer over 63.5 mm (2 -1/2 in) but not over 76.2 mm (3 in)  
 — Crossband lap adjacent to backs (See Sections 5.8.3, 5.8.4)  
5.8.3  Sanded panels  
Unless otherwise specified, sanded plywood shall be sanded on two sides.  Sanding 
characteristics for N, A, B, and C Plugged faces shall be as given i n Section 5.4.  Exposed N, A, 
and B veneer surfaces of panels shall have the bark or tight surface out.  Plies directly under the 
surface of overlaid panels are not considered exposed veneers.  Faces and backs of panels 
shall be full width and full length;  except that C grade and D grade backs shall be permitted to 
be narrow on one edge or short on one end only, but by not more than 3.2 mm (1/8 in) for half 
the panel length or width.  Inner plies shall be full width and length; except that panels other 
than Marine shall be permitted to have one edge or end void not exceeding 3.2 mm (1/8 in) in 
depth and 203 mm (8 in) in length per panel.  Except as otherwise specified in Table  5 for 
specific panel grade designations, crossband veneers not exceeding 3.2 mm (1 /8 in) in 
thickness shall be permitted to be lapped but by not more than 4.8 mm (3/16 in) when adjacent 
to faces, or 12.7 mm (1/2 in) when adjacent to backs, and provided such laps create no 
adjacent visible openings.  Sanding characteristics resulting fro m crossband laps shall not be 
permitted in panel faces.   
29 
 5.8.4  Unsanded and touch -sanded panels  
Grade C or D veneers shall be permitted to be lapped by not more than 12.7 mm (1/2 in) 
provided such laps shall create no adjacent visible opening.  Additional limita tions on laps 
adjacent to panel faces and backs are included in Table 5. All plies of C -D and D -D panels shall 
be full length and full width except that no more than half the length of one edge nor half the 
width of one end shall be permitted to contain sh ort or narrow plies, provided:  
 
(a) Such plies shall not be short or narrow by more than 4.8 mm (3/16 in) except that 
crossbands shall be permitted to be short by 12.7 mm (1/2 in) and centers shall 
be permitted to be narrow by 12.7 mm (1/2 in) provided they taper to within 
4.8 mm (3/16  in) or less of the panel edge in 203 mm (8 in).  
 
(b) When short or narrow by more than 4.8 mm (3/16 in), the aggregate area in the 
plane of the plies of such edge characteristics shall not exceed 39 cm2 (6 in2) in 
the entire panel.  
 
(c) Such edge characteristics shall not occur in more than one ply at any panel cross 
section.  
 
In grades other than C -D and D -D, backs shall be permitted to be narrow on one edge or short 
on one end only, but by not more than 3.2 mm (1 /8 in) for half the panel length or width; inner 
plies shall be full width and length except that one edge or end void not exceeding 3.2  mm 
(1/8 in) in depth and 203 mm (8 in) in length per panel, shall be acceptable.  
 
Panels manufactured as C -C, C-D, D-D, Structural I C -C and Structural I C -D shall not be 
sanded, touch -sanded, surface textured ., or thickness sized by any mechanical means.   Panels 
manufactured as C -C, C-D, D-D, Structural I C -C and Structural I C -D However,  that are  sanded 
or touch -sanded panels which do not meet the grades for which they were intended shall not be 
reclassified and marked as C -C, C-D or D -D, unless the panels shall meet all applicable 
requirements for C -C, C-D or D -D and the finished face and back veneers after sanding shall 
each have a minimum net thickness equal to 90% of the applicable thickness in Table  6 or in 
the mill specification.  (See Section 5.8.7.3.)  
 
For touch sanded panels, indents (see Section 2. 26) shall be considered as an open 
characteristic.  
   
30 
 TABLE 6.  SPAN RATINGS FOR SHEATHING AND SINGLE -FLOOR PANELS BASED ON PRESCRIPTIVE 
SPECIFICATIONS (FOR SPECIAL PLY -LAYER AND SPECIES REQUIREMENTS APPLICABLE TO STRUCTURAL I 
PANELS, SEE SECTION 5.6.5 AND TABLE 4.  FOR CROSSBAND AND TOTAL INNER PLY THICKNESS PROPORTIO N 
REQUIREMENTS, SEE SECTION 5.8.)  
 
   Minimum Face & Back Veneer Thickness  
Before Pressing, for Species Group(b)  
Span  
Rating  
(a)  
 
Panel  
Performance Category  Minimum 
Number  
of Plies - 
Layers   
 
 
1  
 
 
2  
 
 
3  
 
 
4  
Inner Ply  
Species  
Group  
Sheathing Panels (C -D, C-C) 
12/0 5/16  3-3 2.1 mm (1/12 in)  2.1 mm (1/12 in)  2.1 mm (1/12 in)  2.1 mm (1/12 in)  1, 2, 3 or 4  
16/0 5/16 
11/32  3-3 
3-3 2.1 mm (1/12 in)  
2.1 mm (1/12 in)  2.1 mm (1/12 in)  
2.1 mm (1/12 in)  2.1 mm (1/12 in)  
2.1 mm (1/12 in)  (c) 
2.1 mm (1/12 in)  1, 2, 3 or 4  
1, 2, 3 or 4  
20/0(e) 5/16  
11/32  
3/8  3-3 
3-3 
3-3 2.1 mm (1/12 in)  
2.1 mm (1/12 in)  
2.5 mm(1/10 in)  (c) 
2.1 mm (1/12 in)  
2.5 mm (1/10 in)  (c) 
2.5 mm (1/10 in)  
2.5 mm (1/10 in)  (c) 
(c) 
2.5 mm (1/10 in)  1, 2, 3 or 4  
1, 2, 3 or 4  
1, 2, 3 or 4  
24/0 3/8 
13/32  
1/2  3-3 
3-3 
3-3 2.5 mm (1/10 in)  
2.5 mm (1/10 in)  
2.5 mm (1/10 in)  (c) 
2.5 mm (1/10 in)  
2.5 mm (1/10 in)  (c) 
(c) 
2.5 mm (1/10 in)  (c) 
(c) 
2.5 mm (1/10 in)  1, 2, 3 or 4  
1, 2, 3 or 4  
1, 2, 3 or 4  
32/16  1/2  
17/32  
5/8  3-3 
3-3 
3-3 2.5 mm (1/10 in)  
2.5 mm (1/10 in)  
(d) 4.2 mm (1/6 in)  
2.5 mm (1/10 in)  
(d) (c) 
4.2 mm (1/6 in)  
(d) (c) 
(c) 
(d) 1, 2, 3 or 4  
1, 2, 3 or 4  
1, 2, 3 or 4  
40/20(e) 5/8  
21/32  
3/4  
25/32  3-3 
3-3 
4-3 
4-3 (d) 
2.5 mm (1/10 in)  
2.5 mm (1/10 in)  
2.5 mm (1/10 in)  4.2 mm (1/6 in)  
3.2 mm (1/8 in)  
2.5 mm (1/10 in)  
2.5 mm (1/10 in)  (c) 
4.2 mm (1/6 in)  
2.5 mm (1/10 in)  
2.5 mm (1/10 in)  (c) 
(c) 
3.2 mm (1/8 in)  
2.5 mm (1/10 in)  1, 2, 3 or 4  
1, 2, 3 or 4  
1, 2, 3 or 4  
1, 2, 3 or 4  
48/24  3/4  
25/32  
7/8  
29/32  4-3 
4-3 
5-5 
5-5 2.5 mm (1/10 in)  
2.5 mm (1/10 in)  
2.5 mm (1/10 in)  
2.5 mm (1/10 in)  4.2 mm (1/6 in)  
3.2 mm (1/8 in)  
2.5 mm (1/10 in)  
2.5 mm (1/10 in)  (c) 
4.2 mm (1/6 in)  
2.5 mm (1/10 in)  
2.5 mm (1/10 in)  (c) 
(c) 
(c) 
3.2 mm (1/8 in)  1, 2, 3 or 4  
1, 2, 3 or 4  
1, 2, 3 or 4  
1, 2, 3 or 4  
Single -Floor Panels (UNDERLAYMENT, C -C Plugged)  
16 o.c.  1/2  
1519/32  
5/8  3-3 
4-3 
4-3 2.5 mm (1/10 in)  
(d) 
(d) (c) 
(d) 
(d) (c) 
(d) 
(d) (c) 
4.2 mm (1/6 in)  
(d) 1, 2, 3 or 4  
1, 2, 3 or 4  
1, 2, 3 or 4  
20 o.c.(e) 19/32  
5/8  
23/32  
 3/4 4-3 
4-3 
4-3 
4-3 (d) 
(d) 
2.5 mm (1/10 in)  
2.5 mm (1/10 in)  4.2 mm (1/6 in)  
3.2 mm (1/8 in)  
2.5 mm (1/10 in)  
2.5 mm (1/10 in)  (c) 
4.2 mm (1/6 in)  
2.5 mm (1/10 in)  
2.5 mm (1/10 in)  (c) 
(c) 
3.2 mm (1/8 in)  
2.5 mm (1/10 in)  1, 2, 3 or 4  
1, 2, 3 or 4  
1, 2, 3 or 4  
1, 2, 3 or 4  
24 o.c.  23/32  
3/4  
7/8  4-3 
4-3 
5-5 2.5 mm (1/10 in)  
2.5 mm (1/10 in)  
2.5 mm (1/10 in)  4.2 mm (1/6 in)  
3.2 mm (1/8 in)  
2.5 mm (1/10 in)  4.8 mm (3/16 in)  
4.2 mm (1/6 in)  
2.5 mm (1/10 in)  (c) 
(c) 
3.2 mm (1/8 in)  1, 2, 3 or 4  
1, 2, 3 or 4  
1, 2, 3 or 4  
48 o.c.  1-1/8  
1-1/8  
1-1/8 
1-1/8  7-5 
7-5 
7-7 
7-7 3.2 mm (1/8 in)  
3.6 mm (1/7 in)  
2.5 mm (1/10 in)  
3.2 mm (1/8 in)  4.2 mm (1/6 in)  
4.2 mm (1/6 in)  
4.2 mm (1/6 in)  
4.2 mm (1/6 in)  (c) 
(c) 
4.8 mm (3/16 in)  
4.8 mm (3/16 in)  (c) 
(c) 
(c) 
(c) 1 or 2  
1, 2 or 3  
1 
1, 2 or 3  
(a) See Section 5.8.5 for description.  
(b) Intermixing between species groups and/or thicknesses in the faces and backs of panels is permitted.  Use the lowest applicab le span rating 
to identify the panel.  Also see Section 5.5.1.  
(c) Not permitted.  
(d) A minimum of 3.2 mm (1/8 in) for 3, 4 and 5 -ply 3 -layer panels per 5.5.1. A minimum of 2.5 mm (1/10 in) for 5 -ply 5 -layer panels.  
(e) The “20” span  designation is intended for span s of 19.2  inch.  
5.8.5  Span ratings for unsanded and touch -sanded panels  
Grade -trademarking of C -C, C-D, D-D, Structural I C -C, Structural I C -D, and of C -C Plugged 
and Underlayment to be used as combination subfloor -underlayment (single floor) shall include 
a "span rating."  The numbers are presented as a fraction in the marki ng of sheathing grades of 
plywood, and as a single number for C -C Plugged and Underlayment.  They describe the 
maximum spans in inches under normal use conditions and are in accordance with commonly 
accepted criteria.  Panels for which there is no span rat ing shall be identified by largest species 
group number of the face and back, or by the span rating of the next thinner comparable panel.   
  
31 
 For sheathing, the left -hand number shall refer to spacing of roof framing, and the right -hand 
number shall relate to spacing of the floor framing. The single number for Underlayment and 
C-C Plugged refers to spacing of the floor framing in single floor applications.  Actual maximum 
spans are established by local building codes.  
 
When used as single floor, panels shall  also meet the grade requirements of Section 5.6.3.  
 
The span rating number is related to species and thickness of the panel face and back veneers, 
and panel Performance Category . It shall be established by either procedure (a) or (b):  
 
(a) By specificati on as detailed in Table 6, or  
 
(b) By performance testing to satisfy the strength, stiffness and bond criteria as 
detailed in Section 5.8.6.  Such performance testing shall be performed by a 
qualified testing agency, as described in Section 7.2.  
5.8.6  Performanc e testing qualification requirements for span -rated panels  
5.8.6.1  General  
Acceptance of performance tested plywood under this Standard is based upon testing of panel 
strength, stiffness and bond performance. Panels selected for testing shall be of near minimum 
grade and near minimum thickness. Panel average thickness shall be established in 
accordance with Section 5.10.2 .  All provisions of veneer grade and panel workmanship are 
applicable.  
5.8.6.2  Performance testing  
Panels qualified by performance testing sha ll satisfy the criteria called for in Section 5.8.6 when 
tested in accordance with Sections 5.8.6.3 and 5.8.6.4.  
5.8.6.3  Structural performance  
 
Concentrated loads  
Test a maximum of 20 specimens taken from at least 10 panels.  Ten specimens (taken from at 
least f ive panels) for each test exposure condition shall be evaluated for both concentrated 
static and impact loads according to Section 6.2.1.  Requirements are found in Table  7.  If 
additional tests are needed, they shall also consist of 10 specimens, and the results of the two 
10-specimen sets shall be combined.  Only one additional test set is allowed.  If the combined 
results meet or exceed the minimum passing rate, the sample passes.  
Deflection – The initial test set consists of 10 specimens.  
The average de flection shall not be greater than the appropriate requirement in Table  7. 
• If no more than one value is above the requirement, the sample passes.  
• If two or three values are above the requirement, test an additional set.  
• If four or more values are above the  requirement, the sample fails.  
• If ten additional specimens are tested, the combined passing rate shall be at least 85%.   
32 
 Ultimate load  – The initial test set consists of 10 specimens.  
The average load shall not be less than the appropriate requirement in Table 7.  
• If all of the values meet or exceed the requirement, the sample passes.  
• If one of the values is below the requirement, test an additional set.  
• If two or more values are below the requirement, the sample fails.  
• If ten additional specimens are test ed, the combined passing rate shall be at least 95%.  
Uniform loads  
Test a maximum of 20 specimens taken from at least 10 panels.  Ten specimens (taken from at 
least five panels) for each test exposure condition shall be evaluated for uniform load capacity 
according to Section 6.2.2.  Test requirements are found in Table 8.  If additional tests are 
needed, they shall also consist of 10 specimens, and the results of the two 10 -specimen sets 
shall be combined.  Only one additional test set is allowed.   If the combined results meet or 
exceed the minimum passing rate, the sample passes.  
Deflection  – The average deflection shall not be greater than that specified.  The initial test 
consists of 10 specimens.  
• If the average value is below the requirement, t he sample passes.  
• If the average value is above the requirement, test an additional set.  
• If the average value based on combined results is above the requirement, the sample 
fails. 
Ultimate load – The initial test consists of 10 specimens.  The average load  shall not be less 
than the appropriate requirement in Table 8.  
• If all of the values meet or exceed the requirement, the sample passes.  
• If one of the values is below the requirement, test an additional set.  
• If two or more values are below the requirement,  the sample fails.  
• If ten additional specimens are tested, the combined passing rate shall be at least 95%.  
 
 
 
   
33 
  
TABLE 7.  CONCENTRATED STATIC AND IMPACT TEST PERFORMANCE CRITERIA  
FOR PANELS TESTED ACCORDING TO SECTION 6.2.1 (SEE SECTION 5.8.6.3  
FOR PASS/FAIL CRITERIA)  
 
  Performance Criteria  
  Ultimate Load   
End Use – Span 
Rating  Test Exposure  
Conditions(a) Static  Following Impact(b) Deflection  
Under 0.89 kN (200 lbf) Load  
kN lbf kN lbf mm in 
Roof – 16 Dry 
Wet 1.78 400 1.33 300 11.1(c)(d)  0.438(c)(d) 
Roof – 20(f) Dry 
Wet 1.78 400 1.33 300 11.9(c)(d) 0.469(c)(d) 
Roof – 24 Dry 
Wet 1.78 400 1.33 300 12.7(c)(d) 0.500(c)(d) 
Roof – 32 Dry 
Wet 1.78 400 1.33 300 12.7(c)(d) 0.500(c)(d) 
Roof – 40 Dry 
Wet 1.78 400 1.33 300 12.7(c)(d) 0.500(c)(d) 
Roof – 48 Dry 
Wet 1.78 400 1.33 300 12.7(c)(d) 0.500(c)(d) 
Roof – 54 Dry 
Wet 1.78 400 1.33 300 12.7(c)(d) 0.500(c)(d) 
Roof – 60 Dry 
Wet 1.78 400 1.33 300 12.7(c)(d) 0.500(c)(d) 
Subfloor – 16 Dry 
Wet/Redry  1.78 400 1.78 400 4.8(c) 0.188(c) 
Subfloor – 20(f) Dry 
Wet/Redry  1.78 400 1.78 400 5.6(c) 0.219(c) 
Subfloor – 24 Dry 
Wet/Redry  1.78 400 1.78 400 6.4(c) 0.250(c) 
Subfloor – 32 Dry 
Wet/Redry  2.45 550 1.78 400 5.3(c) 0.207(c) 
Subfloor – 48 Dry 
Wet/Redry  2.45 550 1.78 400 8.0(c) 0.313(c) 
Single Floor - 16 Dry 
Wet/Redry  2.45 550 1.78 400 2.0(e) 0.078(e) 
Single Floor - 
20(f) Dry 
Wet/Redry  2.45 550 1.78 400 2.4(e) 0.094(e) 
Single Floor - 24 Dry 
Wet/Redry  2.45 550 1.78 400 2.7(e) 0.108(e) 
Single Floor - 32 Dry 
Wet/Redry  3.11 700 1.78 400 2.2(e) 0.088(e) 
Single Floor - 48 Dry 
Wet/Redry  3.11 700 1.78 400 3.4(e) 0.133(e) 
(a) Wet/redry  shall be exposure to three days of continuous wetting, followed by testing dry. Wet 
conditioning shall be exposure to three days of continuous wetting, then tested wet. Dry shall be  within 
+/- 3% of the as -shipped moisture content.  
(b) Impact shall be 102  N•m (75 lbf•ft) for span ratings up to 24, 122 N•m (90 lbf•ft) for 32, 163  N•m 
(120 lbf•ft) for 40, and 203 N•m (150 lbf•ft) for 48 and greater.  
(c) Criteria apply under static concentrated load. They do not apply following impact.  
(d) Deflection after wet conditioning not applicable.  
(e) Criteria apply under static concentrated load and following impact.  
(f) The “20” span  designation is intended for span s of 19.2 inch.  
 
   
34 
  
TABLE 8.  UNIFORM LOAD PERFORMANCE CRITERIA FOR PANELS TESTED  
ACCORDING TO SECTION 6.2.2  
(SEE SECTION 5.8.6.3 FOR PASS/FAIL CRITERIA)  
 
 Performance Criteria(b) 
 Ultimate  
Uniform Load  
End Use - 
Span Rating  Test Exposure  
Conditions(a) Average Deflection Under Load  
kPa  
lbf/ft2 
Roof - 16 Dry 1.7 mm at 1.68 kPa  (0.067 in. at 35 lbf/ft2) 7.2 150 
Roof - 20 (c) Dry 2.0 mm at 1.68 kPa  (0.080 in. at 35 lbf/ft2) 7.2 150 
Roof - 24 Dry 2.5 mm at 1.68 kPa  (0.100 in. at 35 lbf/ft2) 7.2 150 
Roof – 32 Dry 3.4 mm at 1.68 kPa  (0.133 in. at 35 lbf/ft2) 7.2 150 
Roof – 40 Dry 4.2 mm at 1.68 kPa  (0.167 in. at 35 lbf/ft2) 7.2 150 
Roof – 48 Dry 5.1 mm at 1.68 kPa  (0.200 in. at 35 lbf/ft2) 7.2 150 
Roof – 54 Dry 5.7 mm at 1.68 kPa  (0.225 in. at 35 lbf/ft2) 7.2 150 
Roof – 60 Dry 6.4 mm at 1.68 kPa  (0.250 in. at 35 lbf/ft2) 7.2 150 
Subfloor – 16 Dry 
Wet/Redry  1.1 mm at 4.79 kPa  (0.044 in. at 100 lbf/ft2) 15.8 330 
Subfloor – 20(d) Dry 
Wet/Redry  1.3 mm at 4.79 kPa  (0.053 in. at 100 lbf/ft2) 15.8 330 
Subfloor – 24 Dry 
Wet/Redry  1.7 mm at 4.79 kPa  (0.067 in. at 100 lbf/ft2) 15.8 330 
Subfloor – 32 Dry 
Wet/Redry  2.2 mm at 4.79 kPa  (0.088 in. at 100 lbf/ft2) 15.8 330 
Subfloor – 48 Dry 
Wet/Redry  3.4 mm at 3.83 kPa  (0.133 in. at 80 lbf/ft2) 10.8 225 
Single Floor – 16 Dry 
Wet/Redry  1.1 mm at 4.79 kPa  (0.044 in. at 100 lbf/ft2) 15.8 330 
Single Floor – 20(c) Dry 
Wet/Redry  1.3 mm at 4.79 kPa  (0.053 in. at 100 lbf/ft2) 15.8 330 
Single Floor – 24 Dry 
Wet/Redry  1.7 mm at 4.79 kPa  (0.067 in. at 100 lbf/ft2) 15.8 330 
Single Floor – 32 Dry 
Wet/Redry  2.2 mm at 4.79 kPa  (0.088 in. at 100 lbf/ft2) 15.8 330 
Single Floor – 48 Dry 
Wet/Redry  3.4 mm at 3.83 kPa  (0.133 in. at 80 lbf/ft2) 10.8 225 
(a) Wet/Redry  shall be exposure to three days of continuous wetting, followed by testing dry. Dry shall be as received or 
conditioned with ASTM E 661 within 3% of the as shipped moisture content . 
(b) The panel strength axis shall be placed along the supports for testing across supports , unless otherwise specified.  
(c) The “20” span designation is intended for spans of 19.2 inch.  
 
 
5.8.6.4  Bond performance  
Panels shall be classed as “Exposure 1” or “Exterior.”  
 
Exposure 1 — Panels rated as “Exposure 1” shall be so identified and shall satisfy the bond 
requirements as specified in Section 5.7.1.  
 
Exterior — Panels rated as “Exterior”' shall be so identified and shall satisfy the bond 
requirements specified in Section 5.7.2.  
5.8.6.5  Product evaluation  
  
35 
 Mill specification  — Upon conformance with the appropriate requirements of Sections 5.8.6.3 
and 5.8.6.4, a manufacturing specification unique to the product and mill shall be written based 
on product evaluation. This specification shall be used for quality assu rance purposes by the 
manufacturer and the qualified testing agency, according to Section 5.8.7.3.  Product evaluation 
will be accomplished on the same lot supplied by the manufacturer for qualification testing.  
Reference values shall be established durin g product evaluation or from applicable performance 
requirements in this Standard.  The mill specification shall contain the following information:  
 
Panel construction — Panels shall be defined as to veneer species and construction.  
 
Thickness — The refere nce value shall be the average panel thickness less 1.932 standard 
deviations (the 95% lower tolerance limit at 75% confidence) for twenty panels as sampled 
under Section 5.8.6.1.  
 
Mechanical properties   
 
Bending stiffness — Twenty tests (specimens taken f rom at least ten panels) shall be 
evaluated for bending stiffness both along and across the major panel axis according to the 
procedures of Section 6.2.3.  The reference value for each panel direction shall be the lower 
value of a 90% confidence interval e stablished on the mean.  
 
Bending strength — Ten tests (specimens taken from ten different panels) shall be tested for 
maximum bending moment both along and across the major panel axis according to the 
procedures of Section 6.2.3. The reference values for e ach panel direction will be the minimum 
observed value, or the sample mean less 1.8 times the sample standard deviation, whichever is 
the higher value.  
5.8.7  Performance testing qualification requirements for other than span -rated panels  
5.8.7.1  General  
Panels using spe cies as provided in Section 5.2.4 shall be qualified for use under this Standard 
based upon testing of panel strength and stiffness in accordance with Section 5.8.7.2.  Results 
of testing shall establish a Group classification for use as required in Sectio n 7.3 (a).  Group 
classification established by panel testing shall be determined by the largest Group number 
obtained from all performance tests.   
5.8.7.2  Performance testing  
 
Bending stiffness  — A minimum of twenty tests (specimens taken from at least ten panel s) 
shall be evaluated for bending stiffness both along and across the major panel axis according to 
the procedures of Section 6.2.3.  At least 90% of specimens tested along the major axis shall 
meet the minimum stiffness value along the major axis given in  Table 9 for the Performance 
Category tested.  
 
   
36 
 TABLE 9.  SPECIES GROUP CLASSIFICATION TEST CRITERIA FOR OTHER  
THAN SPAN -RATED PANELS  
 
  Shear Through  Stress Along (Parallel to Face)  
Performance 
Category   
Group  Thickness 
Strength   
Bending Stiffness   
Bending Strength  Planar Shear  
Strength 
  kN/m (lbf/in)  kN•m2/m (lbf•in2/ft) kN•m/m (lbf•in/ft)  kN/m (lbf/ft)  
 1/4 1 21.0 (120)  0.15 (  16 000)  0.087 (  235)  3.7 (  255)  
 2 15.8 (  90)  0.12 (  13 000)  0.063 (  170)  3.7 (  255)  
 3 15.8 (  90) 0.10 (  10 500)  0.063 (  170)  3.7 (  255)  
 4 14.5 (  83)  0.08 (    8 800)  0.057 (  155)  3.7 (  255)  
 11/32  1 22.8 (130)  0.35 (  37 500)  0.137 (  370)  5.1 (  350)  
 2 16.6 (  95)  0.30 (  31 500)  0.100 (  270)  5.1 (  350)  
 3 16.6 (  95)  0.24 (  25 000) 0.100 (  270)  5.1 (  350)  
 4 15.6 (  89)  0.20 (  21 000)  0.093 (  250)  5.1 (  350)  
 3/8 1 22.8 (130)  0.50 (  53 500)  0.183 (  495)  5.8 (  395)  
 2 17.0 (  97)  0.42 (  44 500)  0.133 (  360)  5.8 (  395)  
 3 17.0 (  97)  0.33 (  35 500)  0.133 (  360) 5.8 (  395)  
 4 15.8 (  90)  0.28 (  29 500)  0.124 (  335)  5.8 (  395)  
15/32  1 33.3 (190)  1.22 (130 000)  0.313 (  845)  7.7 (  525)  
 2 24.5 (140)  1.04 (110 000)  0.228 (  615)  7.7 (  525)  
 3 24.5 (140)  0.82 (  87 000)  0.228 (  615)  7.7 (  525)  
 4 22.8 (130)  0.68 (  72 500)  0.211 (  570)  7.7 (  525)  
 1/2 1 34.1 (195)  1.41 (150 000)  0.347 (  935)  8.3 (  570)  
 2 25.4 (145)  1.18 (125 000)  0.252 (  680)  8.3 (  570)  
 3 25.4 (145)  0.94 (100 000)  0.252 (  680)  8.3 (  570)  
 4 23.6 (135)  0.80 (  84 500) 0.234 (  630)  8.3 (  570)  
 19/32  1 43.8 (250)  2.17 (230 000)  0.463 (1250)  10.1 (  695)  
 2 32.4 (185)  1.79 (190 000)  0.335 (  905)  10.1 (  695)  
 3 32.4 (185)  1.41 (150 000)  0.335 (  905)  10.1 (  695)  
 4 29.8 (170)  1.18 (125 000)  0.311 (  840)  10.1 (  695)  
 5/8 1 43.8 (250)  2.40 (255 000)  0.500 (1350)  10.8 (  740)  
 2 32.4 (185)  2.02 (215 000)  0.361 (  975)  10.8 (  740)  
 3 32.4 (185)  1.60 (170 000)  0.361 (  975)  10.8 (  740)  
 4 29.8 (170)  1.32 (140 000)  0.335 (  905)  10.8 (  740)  
 23/32  1 44.7 (255)  3.34 (355 000)  0.575 (1550)  12.2 (  835)  
 2 33.3 (190)  2.78 (295 000)  0.408 (1100)  12.2 (  835)  
 3 33.3 (190)  2.21 (235 000)  0.408 (1100)  12.2 (  835)  
 4 30.6 (175)  1.84 (195 000)  0.389 (1050)  12.2 (  835)  
 3/4 1 45.5 (260)  3.67 (390 000)  0.612 (1650)  12.6 (  860)  
 2 33.3 (190)  3.06 (325 000)  0.445 (1200)  12.6 (  860)  
 3 33.3 (190)  2.45 (260 000)  0.445 (1200)  12.6 (  860)  
 4 30.6 (175)  2.02 (215 000)  0.408 (1100)  12.6 (  860)  
 7/8 1 46.4 (265)  5.18 (550 000)  0.760 (2050)  14.6 (1000)  
  2 34.1 (195)  4.33 (460 000)  0.556 (1500)  14.6 (1000)  
 3 34.1 (195)  3.44 (365 000)  0.556 (1500)  14.6 (1000)  
 4 32.4 (185)  2.87 (305 000)  0.500 (1350)  14.6 (1000)  
 1 1 65.7 (375)  7.91 (840 000)  0.982 (2650)  16.8 (1150)  
  2 48.2 (275)  6.59 (700 000)  0.704 (1900)  16.8 (1150)  
 3 48.2 (275)  5.27 (560 000)  0.704 (1900)  16.8 (1150)  
 4 44.7 (255)  4.38 (465 000)  0.649 (1750)  16.8 (1150)  
 1-1/8 1 66.5 (380)  10.36 (1 100 000)  1.205 (3250)  18.3 (1250)  
 2 49.0 (280)  8.52 (905 000)  0.871 (2350)  18.3 (1250)  
 3 49.0 (280)  6.83 (725 000)  0.871 (2350)  18.3 (1250)  
 4 45.5 (260)  5.70 (605 000)  0.816 (2200)  18.3 (1250)  
  
37 
 Bending strength  — A minimum of ten tests (specimens taken from ten different panels) shall 
be tested for bending strength both along and across the major panel axis according to the 
procedures of Section 6.2.3.  At least 95% of the specimens tested along the major axis 
direction shall meet the value given in Table 9 for the Performance Category tested.  
 
Planar shear strength  — A minimum of ten tests (specimens taken from ten different panels) 
shall be tested for planar shear strength along the major panel axis according t o the procedures 
of Section 6.2.4.  At least 95% of the tests shall meet the planar shear strength value along the 
major axis given in Table 9 for the Performance Category  tested.  
 
Shear -through -the-thickness strength — A minimum of ten tests (specimens ta ken from ten 
different panels) shall be tested for shear strength through the thickness according to the 
procedures of Section 6.2.5.  At least 95% of tests shall meet the shear -through -the-thickness 
strength value given in Table 9 for the Performance Cate gory tested.  
5.8.7.3  Mill specification  
Upon conformance with the requirements of Section 5.8.7.2, a manufacturing specification 
unique to the product and mill shall be written.  This specification shall be used for quality 
assurance purposes by the manufacturer a nd the qualified testing agency defined in 
Section  7.2.  The manufacturing specification shall define veneer species and panel 
construction and shall include the following reference values:  
 
Thickness  — The reference value shall be the average panel thickn ess less 1.932 standard 
deviations (the 95% lower tolerance limit at 75% confidence) for twenty panels tested under 
Section 5.8.7.2.  
 
Mechanical Properties  
 
Bending stiffness  — The reference values for each panel direction shall be the lower value of 
a 90% confidence interval (see ASTM D 2915) established on the mean for each panel 
direction.  
 
Bending strength — The reference values for each panel direction shall be the minimu m 
observed value, or the sample mean less 1.8 times the sample standard deviation, whichever is 
the higher value for each panel direction.  
 
Planar shear strength — The reference value shall be the minimum observed value, or the 
sample mean less 1.8 times t he sample standard deviation whichever is the higher value  
 
Shear -through -the-thickness strength  — The reference value shall be the minimum observed 
value, or the sample mean less 1.8 times the sample standard deviation, whichever is the 
higher value.  
 
As an alternative to the mechanical properties, the performance tests of Section 5.8.7.2 may 
also be used for quality assurance purposes.  
5.9 Scarf and finger jointed panels  
Neither panels with N faces, nor the faces of such panels, unless longer than 3 m (10 ft ), shall 
be scarf or finger jointed unless otherwise agreed to by buyer and seller.  Panels of other 
grades shall be permitted to be scarf or finger jointed unless otherwise agreed to by buyer and 
seller, and panels longer than 3.7 m (12 ft) are necessaril y scarf or finger -jointed.  Plain scarfed 
joints and the scarfed portion of finger -joints shall not have a slope greater than 1 to 8.  All plies  
38 
 with grain perpendicular to the finger joint shall be included in the scarfed portions of the joint, 
except tha t such plies shall be permitted to include up to 0.8 mm (1/32 in) of vertical shoulder in 
the scarf (see Figure 1).  Joints shall be bonded with a moisture resistant adhesive and shall 
meet the test requirements set forth in Sections 5.9.1, 5.9.2, and 5.9. 3 as applicable.  In 
addition, the adhesive shall not show creep or flow characteristics greater than unjointed wood 
when subject to load under any conditions of temperature and moisture.  
 
 
Figure 1.  Finger joints – Location of scarfed portion of joints.  
5.9.1  Strength requirements for scarf and finger jointed panels  
If the average ultimate stress of the three test specimens of any one panel is less than 
27.6 MPa (4000 psi) for panels of Group 1 species, or less than 19.3 MPa (2800 psi) for panels 
of Group 2 o r Group 3 species, or less than 16.5 MPa (2400 psi) for panels of Group 4 species, 
or less than 13.8 MPa (2000 psi) for panels of Group 5 species, when tested in accordance with 
Section 6.1.5.1, then that panel shall fail.  The jointed panels represented b y a sampling of ten 
panels shall be acceptable if not more than one of the panels fails and the average ultimate 
stress of the failing panel is at least 80% of that specified for the applicable species group.  If 
the average ultimate stress of the failing panel is at least 75% of that specified for the applicable 
species group, another series of ten panels shall be tested.  If none of the panels in this series 
fails, the jointed panels shall be accepted; otherwise they shall be rejected.  
 
39 
 5.9.2  Scarf joint bond pe rformance for Exposure 1 and Exterior plywood  
Panels shall be tested in accordance with Section 6.1.5.2.  The material represented by the 
sampling shall be evaluated in accordance with Sections 5.7.1, and 5.7.2, as applicable.  
5.9.3  Finger joint bond performance  for Exposure 1 and Exterior plywood  
Panels shall be tested in accordance with Section 6.1.5.3.  The joints shall meet all of the 
following minimum conditions:  
 
(a) The average wood failure rating of all specimens from each panel when tested in 
accordance with Section 6.1.5.3 shall be not less than 85%.  
 
(b) No single specimen from a panel (average of face and back bond lines) shall rate 
less than 60% wood failure.  
 
(c) No single face or back bond line in any specimen shall rate less than 30% woo d 
failure.  
5.10 Dimensional tolerances and squareness of panels  
Panel measurements shall be based on a moisture content of 9%.  
5.10.1  Size tolerances  
A length and a width measurement shall be made at a location 50 to 75 mm (2 to 3 in.) from the 
panel edge. A toleranc e of A tolerance of plus zero (0) mm, minus 1.6 mm (1/16 in) shall be 
allowed on the specified manufacturer’s stated  length and /or width.  
ADVISORY NOTE: For tongue and grooved and ship -lapped panels , the w idth and squareness 
measurements  should be made on the net panel face.   
5.10.2  Performance Category and thickness tolerances  
 
Panel thickness shall be measured with a micrometer having 19.1 mm (3/4 in) (minus 0, plus 
1.3 mm [0.050 in]) diameter anvils. Measurement s shall be taken at an applied anvil pressure of 
not less than 34 kPa (5 psi) or more than 69 kPa (10 psi). The location of the measurements shall 
be representative of panel thickness mid -length ,+/- 50 mm (2 in.) along each edge of the panel and the 
average of the four measurements shall be taken as the thickness of that panel. The location of the 
measurement s shall be representative of general panel thickness at approximate mid -length 
along each edge of the panel and the average of the four measurements shall be taken as the 
thickness of that panel.  If a measurement point contains a permissible grade characteristic that 
affects panel  thickness, then the measurement point shall be shifted from that point.  
 
The panel  thickness shall conform to Table 10. 
  Formatted:  Body1,  Tab stops:   0", Left + Not at  0.5" 
40 
 TABLE 10.  PLYWOOD THICKNESS REQUIREMENTS  
 
 Thickness Requirements for  
Unsanded, Touch Sanded and  
Overlaid Grades1 Thickness Requirements for  
Sanded Grades2 
PERFORMANCE 
CATEGORY3 Minimum 
Thickness, mm 
(in.) Maximum 
Thickness, mm 
(in.) Minimum 
Thickness, mm 
(in.) Maximum 
Thickness, mm  
(in.) 
1/4 PERF CAT  5.56 (0.219)  7.14 (0.281)  5.95 (0.234)  6.75 (0.266)  
11/32 PERF CAT  7.94 (0.313)  9.53 (0.375)  8.33 (0.328)  9.13 (0.359)  
3/8 PERF CAT  8.73 (0.344)  10.32 (0.406)  9.13 (0.359)  9.92 (0.391)  
 7/16 PERF CAT  10.32 (0.406)  11.91 (0.469)  10.72 (0.422)  11.51 (0.453)  
15/32 PERF CAT  11.11 (0.438)  12.70 (0.500)  11.51 (0.453)  12.30 (0.484)  
 1/2 PERF CAT  11.91 (0.469)  13.49 (0.531)  12.30 (0.484)  13.10 (0.516)  
9/16 PERF CAT  13.49 (0.531)  15.08 (0.594)  13.89 (0.5 47) 14.68 (0.578)  
19/32 PERF CAT  14.29 (0.563)  15.88 (0.625)  14.68 (0.578)  15.48 (0.609)  
5/8 PERF CAT  15.08 (0.594)  16.67 (0.656)  15.48 (0.609)  16.27 (0.641)  
23/32 PERF CAT  17.46 (0.688)  19.05 (0.750)  17.86 (0.703)  18.65 (0.734)  
3/4 PERF CAT  18.26 (0.719)  19.84 (0.781)  18.65 (0.734)  19.45 (0.766)  
13/16 PERF CAT  19.84 (0.781)  21.43 (0.844)  20.02 (0.788)  21.26 (0.8 37)  
7/8 PERF CAT  21.11 (0.831)  23.34 (0.916) 21.56 (0.849)  22.89 (0. 901)  
1 PERF CAT  24.13 (0.950)  26.67 (1.0 50) 24.64 (0.970)  26.16 (1.0 30)  
1-1/8 PERF CAT  27.15 (1.069)  30.00 (1.1 81) 27.72 (1.091)  29.43 (1.1 59)  
1-1/4 PERF CAT  30.16 (1.188)  33.34 (1. 313) 30.80 (1.213)  32.70 (1.2 88)  
1Thickness requirements for unsanded, touch sanded, and overlaid panels are based on a tolerance of ± 0.8 mm 
(1/32 in.) for panels with Performance Categories  of 13/16 and less and ± 5% for panels with Performance 
Categories greater than 13/16 unless a closer tolerance is determined through qualification testing.  
 
2Thickness requirements for sanded panels is based on a tolerance of ± 0.4 mm (1/64 in.) for panels with 
Performance Categories  of 3/4  and less and ± 3.0% for panels with Performance Categorie s greater than 3/4  unless 
a closer tolerance is determined through qualification testing.  
 
3 For labeling purposes, abbreviation of “Performance Category” by PERF CAT, CAT or Category is permitted.  
Performance Categories for other panel thicknesses are pe rmitted.  
5.10.3  Squareness and straightness  
Squareness and straightness - Panels shall be square within 1.3 mm per lineal meter of the 
longest edge (1/64 in per lineal foot) measured along the diagonals.  All panels shall be 
manufactured so that a straight line d rawn from one corner to the adjacent corner is within 
1.6 mm (1/16 in) of the panel edge.  
5.11 Moisture content  
Moisture content of panels at time of shipment shall not exceed 18% when tested in accordance 
with Section 6.1.4.  
5.12 Loading or packing  
The plywood sh all be securely loaded or packaged to ensure delivery to destination in a clean 
and serviceable condition.  
6  SPECIMEN PREPARATION AND TESTING  
6.1 Bond classification  
6.1.1  General  
The tests set forth in this section shall be used to determine the adhesive bond quality of 
plywood produced under this Standard.   
41 
 6.1.2  Specimen preparation (see appendix B for sampling for reinspection)  
Testing shall follow the principles of ASTM D906 and procedures herein. One test piece shall be 
cut from each panel selected.  Unless other wise specified by the qualified testing agency, 10 
test specimens shall be cut as described in Section 6.1.3.1 for panels bonded with moisture -
resistant adhesive.  Of the 10 specimens cut from each test piece for panels bonded with 
moisture resistant adhes ive, 5 shall be for the vacuum -pressure test and 5 shall be for the boil 
test.  In addition, from each panel selected, a specimen 140 mm by 203  mm (5 -1/2 x 8 in) shall 
be cut and tested as described in Section 6.1.3.4.  
6.1.3  Tests for Exposure 1 and Exterior ply wood.  
6.1.3.1  Preparation of test specimens  
Test specimens taken as described in Section 6.1.2 shall be cut 82.6 mm long by 25.4  mm wide 
(3-1/4 in x 1 in), and kerfed one -third of the length of the specimen from each end, as illustrated 
in Figure 2 to provide a 25 .4 mm (1 in) square test area in the center.  Specimens shall be 
oriented so that the grain direction of the ply under test runs at a 90° angle to the length of the 
specimen.  Kerfing shall extend two -thirds of the way through the ply under test, and shall  not 
penetrate the next bond line.  For overlaid plywood, the additional 10 specimens for testing of 
bond between veneers shall be cut as described in this section for Exterior specimens except 
that they shall be cut 25.4 mm (1 in) wide and 76.2 mm (3 in) long, and kerfed just through the 
overlay 25.4 mm (1 in) from the end, on each overlay face.  
 
 
Figure 2.  Shear test specimens.  
 
If the number of plies exceeds three, the cuts shall be made so as to test any two of the joints, 
but the additional plies nee d not be stripped except as demanded by the limitations of the width 
of the retaining jaws on the testing device.  When required to accommodate thicker plywood, 
special jaws shall be constructed.  If the number of plies exceeds three, the choice of joints to 
be tested shall be left to the discretion of the qualified inspection and testing agency, but at least 
one-half of the tests shall include the innermost joints.  
6.1.3.2  Vacuum -pressure test  
The test specimen shall be placed in a pressure vessel and submerged in  cold tap water.  A 
vacuum of 83.5 to 98.5 kPa or 24.7 to 29.0 inches of mercury shall be drawn and maintained for 
30 minutes, followed immediately with application of 450 kPa to 480 kPa (65 psi to 70 psi) of 
pressure for 30 minutes duration.  Specimens sh all then be removed from the vessel and tested 
while wet by tension loading to failure in a shear testing machine operated at a maximum head 
travel of 406 mm (16 in) 762 mm (30 in)  per minute.  The jaws of the machine shall securely grip 
the specimens so there is no slippage.  The percentage of wood failure of the specimens shall 
 
42 
 be determined in a dry condition in accordance with ASTM D5266 and evaluated as described 
in Sections 5. 7.1 and 5.7.2.  
 
The bond between veneers in overlaid plywood shall be tested in an identical manner and 
evaluated as described in Section 5.7.2.  Specimens for testing the bond between the overlay 
and the base panel shall be subjected to the same test cycle just described .  The bond between 
the overlay and the base panel shall be tested by inserting a sharp, thin blade of adequate 
stiffness into the corner of the 25.4 mm (1 in) test area at the overlay -veneer interface, taking 
care not to cut into the overlay, and attempti ng to peel the overlay off.  Reinsertion of the blade 
several times shall be permitted if necessary to remove the overlay from the 6.5 cm2 (1 in2) area.  
The percentage of wood and/or fiber failure shall then be estimated with specimens in a dry 
condition in accordance with ASTM D5266 and evaluated as described in Section 5.7.2.  The 
value for each specimen shall be the average of the test areas on each face.  
6.1.3.3  Boiling test  
Test specimens shall be boiled in water for 4 hours and then dried for 20 hours at a temperature 
of 63  3°C (145  5°F) with sufficient air circulation to lower moisture content of the specimens 
to a maximum of 8%.  The specimens shall be boiled again for a period of 4 hours, cooled in 
water, and tested while wet by tension loading to failure in a shear testing machine operated at 
a maximum head travel of 406 mm (16 in) per minute.  Jaws of the machine shall securely grip 
the specimens so there is no slippage.  The percentage of wood failure of  the specimens shall 
be determined with specimens in a dry condition  in accordance with ASTM D5266  and 
evaluated as described in Sections 5.7.1 and 5.7.2.  
 
The bond between veneers in overlaid plywood shall be tested in an identical manner and 
evaluated as  described in Section 5.7.2.  Specimens to test the bond between the overlay and 
the base panels shall be subjected to the same test cycle described in the previous paragraph.  
The bond between the overlay and the base panel shall be tested by inserting a sharp, thin 
blade of adequate stiffness into the corner of the 25.4 mm (1 in) test area at the overlay -veneer 
interface, taking care not to cut into the overlay, and attempting to peel the overlay off.  
Reinsertion of the blade several times shall be permi tted if necessary to remove the overlay 
from the 6.5 cm2 (1 in2) area.  The percentage of wood and/or fiber failure shall then be 
estimated with specimens in a dry condition in accordance with ASTM D5266 and evaluated as 
described in Section 5.7.2.  The va lue for each specimen shall be the average of the test areas 
on each face.  
6.1.3.4  Heat performance test  
A specimen cut as described in Section 6.1.2 shall be placed on a stand as illustrated in 
Figure  3.  A specimen shall then be subjected to a 800°C to 900°C (14 72°F to 1652°F) flame 
from a Bunsen -type burner for a period of 10 minutes, or until a brown charred area appears on 
the back side, whichever occurs first.  The burner shall be equipped with a wing top to envelop 
the entire width of the specimen in flame.  The top of the burner shall be 25.4 mm (1 in) from the 
specimen face and the flame 38.1 mm (1 -1/2 in) high.  The flame shall impinge on the face of 
the specimen 50.8 mm (2 in) from the bottom end.  After the test, the sample shall be removed 
from the stan d and the bond lines examined for delamination by separating the charred plies 
with a sharp, chisel -like instrument.  Specimens shall be evaluated in accordance with the 
requirements of Section 5.7.2.1.  
  
43 
  
Figure 3.  Apparatus for heat durability test.  
6.1.4  Test for determination of moisture content (oven -drying method)  
The moisture content of the plywood shall be determined as follows:  A small test specimen 
shall be cut from each sample panel; the test specimen shall measure not less than 58 cm2 
(9 in2) in are a and shall weigh not less than 20 grams (approximately 3/4 ounce).  All loose 
splinters shall be removed from the specimen.  The specimen shall be immediately weighed on 
a scale that is accurate to 0.5%, and the weight shall be rec orded as the “original” weight.  The 
specimen shall then be dried in an oven at 100°C to 105°C (212°F to 221°F) until constant 
weight is attained.  After drying, the specimen shall be reweighed immediately, and this weight 
shall be recorded as the “oven -dry” weight.  The moisture content shall be calculated as follows:  
 
(%) content Moisture  100  ) dry weight (Oven) dry weight (Oven  -   weight) (Original=
 
6.1.5  Scarf and finger -joint tests  
6.1.5.1  Scarf and finger -joint strength  
Three test specimens shall be cut at random along each joint from each panel selected.  Type, 
grade and species of the panels shall be recorded.  The specimens shall be cut so as to include 
the joint and shall be prepared as illustrated in Figure 4.  
 
44 
  
Figure 4.  Tension specimen for scarf jointed panels.  
 
Insofar as possible, the joint test area shall contain no localized natural characteristics permitted 
within the grade.  At the joint, the maximum thickness and width of plies parallel with the load 
shall be recorded.  Each specimen shall then be placed in the tension grips of a testing machine 
and loa ded continuously at a rate of cross -head travel of from 0.8 mm to 1.0 mm (0.030 in to 
0.040 in) per minute until failure, and the ultimate load shall be recorded.  The ultimate stress in 
MPa (psi) shall be computed using the ultimate load and area of those  plies whose grain is 
parallel with direction of load.  Moisture content of the specimens at the time of testing shall not 
exceed 16%.  
6.1.5.2  Scarf joint bond performance of Exterior and Exposure 1 plywood  
Ten test specimens shall be cut at random along each join t from each panel selected according 
to Section 6.1.2.  The specimens shall be prepared following the general procedure described in 
Section 6.1.3.1 and shall be cut so that the joint runs through the test specimens as shown in 
Figure 5.  
 
 
Figure 5.  Spec imen preparation.  
 
Five specimens shall be subjected to the vacuum -pressure test described in Section 6.1.3.2, 
and five to the boiling test of Section 6.1.3.3.  The panels shall be evaluated as described in 
Sections 5.7.1 and 5.7.2.  
6.1.5.3  Finger -joint bond perfo rmance of Exterior and Exposure 1  
Ten specimens shall be cut at random along the finger joint from each panel selected according 
to Section 6.1.2.  These specimens shall be cut so as to include the joint and shall be prepared 
as illustrated in Figure 6.  
 
 
45 
  
Figure 6.  Cleavage test, typical test specimen.  
 
Five of the specimens shall be subjected to the vacuum -pressure test of Section 6.1.3.2 and five 
to the boiling test of Section 6.1.3.3.  
 
Upon completion of the applicable moisture cycle(s), a wedge or chi sel (see Figure 7) shall be 
inserted in locations shown in Figure 6 in such a manner as to pry apart the scarfed portions of 
the joint without directly contacting the bonded area.  Test specimens shall be dried and percent 
wood failure in the test area est imated and applied separately for both the boil and vacuum -
pressure treatments.  The panels shall be evaluated as described in Section 5.9.3.  
 
 
Figure 7.  Wedge or chisel used for cleavage test.  
6.2 Structural performance  
6.2.1  Tests for performance under concentrated static and impact loads  
6.2.1.1  General  
The general provisions of ASTM E 661 shall be followed  except as modified in these  sections .  
 
The test span shall be 19.2 inch for the span rating of 20 .  
 
The dry test condition shall be within +/ - 3% of the a s-shipped moisture content. The wet test 
condition shall be exposure to three days of continuous wetting, then tested wet. The wet/redry 
condition shall be exposure to three days of continuous wetting, followed by testing within 3% of 
the as -shipped moistu re content . 
6.2.1.2  Specimen preparation  
Test specimens shall be prepared as specified in ASTM E 661. The number of specimens 
required is given in Section 5.8.6.3.  Specimens shall also be moisture cycled as required.  
  
 
46 
 6.2.1.3  Test procedure  
 
Concentrated static — Proced ures of ASTM E 661 shall be followed, except the test frame 
shall be constructed of lumber with nails or of steel using fasteners which simulate nails.  The 
loading rate shall be 445 N (100 lbf) per 30 seconds to yield failure within 5 minutes if a hand -
pumped hydraulic loading system is used.  
 
Concentrated impact  — Procedures of ASTM E 661 Method A shall be followed, except:  
 
(a) The test frame shall be constructed of lumber with nails or of steel using 
fasteners which simulate nails.  
 
(b) For span ratings greater than 24 o.c., the shot bag shall weigh 27 kg (60 
pounds).  
 
The width of individual pieces in assembling a test shall be 610 mm (24 in) or greater for span 
ratings up to 24 o.c., and 1220 mm (48 in) for greater span ratings.  
6.2.2  Test fo r performance under uniform loads  
6.2.2.1  General  
This method shall determine the performance of structural -use panels under uniform loads such 
as snow, wind and occupancy loads.  The uniform load is applied by atmospheric pressure as a 
vacuum is drawn under the t est specimen, which is mounted on fully -supported framing 
members in a vacuum chamber.  
6.2.2.2  Equipment  
 
Vacuum chamber  — The vacuum chamber (see Figure 8) shall consist of a sealed box with 
the panel to be tested forming the top.  A 0.15 mm (6 mil or 0.006 in) p olyethylene sheet or 
equivalent, the perimeter of which is attached securely with tape, shall seal the top surface of 
the vacuum chamber.  The chamber shall be strong and rigid to resist the applied load without 
failure or excessive deformation.  A vacuum pump shall be used to reduce the air pressure 
under the specimen.  The load shall be measured with absolute pressure gages for electronic 
data readout, but manometers or vacuum gages shall also be permitted.  
  
47 
  
Figure 8.  Vacuum chamber test equipment.  
 
Joist supports — The framing members shall be spaced at the intend ed span rating, except 
that 20 span rating shall have framing spaced 19.2 inch. Framing shall be supported so as to 
resist deflection or rotation under applied load.  
 
Deflection gages  — The de flection gages shall be mounted to rigid tripods whose legs rest 
above the joists.  Deflection shall be measured to the nearest 0.03 mm (0.001 in).  
6.2.2.3  Specimen preparation  
Samples shall be selected that are representative of the product being tested.  
 
Length — The specimen length perpendicular to the framing member shall be equal to twice 
the center -to-center spacing.  
 
Width  — The specimen width shall be at least 597 mm (23 -1/2 in).  
 
Thickness — The specimen thickness shall be measured after conditionin g and recorded.  
6.2.2.4  Test procedure  
After conditioning, the specimen to be tested shall be mounted on the framing members in the 
vacuum chamber in accordance with the anticipated joist spacing and the recommended nail 
size and spacing.  The top of the vacuum c hamber shall then be sealed with the polyethylene 
sheet, and the tripod holding the deflection gages set in its proper position with the gages 
positioned to read deflection at the point of maximum deflection2 of the two outer spans 
(Figure  9). 
 
                                                 
2 The point of maximum deflection for a uniformly loaded two -span system shall occur at 0.4215 (S) 
measured from the centerline of the outer joist, where S equals the center -to-center joist spacing.  
 
48 
  
Figure 9.   Uniform -load test specimens.  
 
The panel shall be loaded at a uniform rate of 2.4 kPa (50 lbf/ft2) per minute and deflections 
recorded at 1.2 kPa (25 lbf/ft2) increments until maximum load is achieved or until the desired 
proof load is achieved, as requir ed.  Deflection data shall be required only in sufficient numbers 
to develop the straight line portion of the load -deflection curve.  In no case shall the number of 
data points be less than six.  Deflection at a given load shall be determined by translatin g the 
slope to pass through the origin, thereby correcting for any settling of the system.  
6.2.3  Test for panel bending  
6.2.3.1  General  
This test procedure shall provide the basic data regarding full panel bending strength and 
stiffness.  The general provisions of ASTM  D 3043 Method C shall be followed.  
6.2.3.2  Specimen preparation  
Specimens shall be prepared according to ASTM D 3043 Method C.  
6.2.3.3  Test procedure  
The procedures of ASTM D 3043 Method C shall be followed except specimens shall be tested 
for stiffness both along and across the major panel axis, and the maximum bending moment 
shall be taken as required.  
6.2.4  Test for planar shear strength  
6.2.4.1  General  
This test procedure shall determine the shear strength of plywood panels associated with shear 
distortion of the planes paral lel to the edge planes of the panel.  The general provisions of 
ASTM D 2718 shall be followed.  
 
49 
 6.2.4.2  Specimen preparation  
Specimens shall be prepared in accordance with ASTM D 2718.  Specimens shall be prepared 
to evaluate planar shear with the face grain direct ion parallel to the long dimension  
6.2.4.3  Test procedure  
The procedures of ASTM D 2718 (Method A or Method B) shall be followed.  Lumber side 
plates may be used in lieu of steel plates in Method A.  The planar shear strength shall be 
measured parallel to the fac e grain direction.  
6.2.5  Test for shear -through -the-thickness strength  
6.2.5.1  General  
This test procedure shall determine the shear strength when loads are developed along 
opposite edges of panels.  The general provisions of ASTM D 2719 Method C shall be followed.  
6.2.5.2  Specimen preparation  
Specimens shall be prepared in accordance with ASTM D 2719 Method C - Two Rail Test.   
6.2.5.3  Test procedure  
The procedures of ASTM D 2719 Method C shall be followed.  The shear -through -the-thicknes s 
strength shall be measured and reported as a capacity, F vtv. 
7 GRADEMARKING AND CERTIFICATION  
7.1 Certification  
Plywood represented as being in conformance with this Standard shall bear the stamp mark of a 
qualified inspection and testing agency which (1) either inspects the manufacture (with 
adequate sampling, testing of bond line, and examination for quality of all veneers) or (2)  has 
tested a random sampling of the finished panels in the shipment being certified for conformance 
with this standard.  The mark shall maintain le gibility after weather exposure during construction.  
7.2 Qualified inspection and testing agency  
A qualified inspection and testing agency is defined to be one that:  
 
(a) has the facilities and trained technical personnel to verify that the grading, measuring , species, 
construction, sanding, bonding, workmanship, and other characteristics of the products as determined by 
inspection, sampling and testing conform to all of the applicable requirements specified herein;  
 
(b) has developed procedures to be followed  by agency personnel in performance of the inspection 
and testing;  
  
 
(c) has no financial interest in, or is not financially dependent upon, any single 
company manufacturing the product being inspected or tested; and  
 
(d) is not owned, operated or control led by any such company.  
 
(a) A qualified inspection agency is defined as one that is accredited to ISO/IEC 
17020, Conformity Assessment – Requirements for the Operation of Various 
Types of Bodies Performing Inspections. An agency accredited to ISO/17065, 
Conformity Assessment -Requirem ents for Bodies Certifying Processes and 
Services and meets the applicable requirements of ISO/IEC 17020 and has Formatted:  Font: 9 pt
Formatted:  Default,  Indent:  Left:  0.5", First line:  0"
Formatted:  Indent:  Left:  0.5"
Formatted:  Font: 11 pt
Formatted:  Indent:  Left:  0.44",  Hanging:   0.56",  Numbered
+ Level:  3 + Numbering  Style:  a, b, c, … + Start at: 1 +
Alignment:  Left + Aligned  at:  1.5" + Tab after:   1.75" +
Indent  at:  1.75",  Tab stops:  Not at  1.75" 
50 
 inspections included in its certification scheme meets the definition of qualified 
inspection agency.  
 
(b) A qualified testing agency is defined as one that is accredited to ISO/IEC 17025, 
General Requirements for the Competence of Testing and Calibration 
Laboratories. An agency accredited to ISO/17065, Conformity Assessment -
Requirements for Bodies Certifying P rocesses and Services and meets the 
applicable requirements of ISO/IEC 17025 and has testing included in its 
certification scheme meets the definition of qualified testing agency.  
 
7.3 Panel marking  
All panels represented as conforming to this Standard shall be identified with marks giving the 
following information:  
 
(a) Species group number, span rating and class — Unless otherwise provided, 
panels which are produced with face and back veneers of the same species 
group shall be identified as being of that spe cies group.  Touch -sanded panels 
without span ratings that are manufactured with face and back plies of different 
species groups shall be identified by the larger numbered species group (i.e., 
Group 4 is larger numbered than Group 1).  Sanded panels with P erformance 
Category of 3/8  or less, and Decorative panels of any Performance Category , 
that are manufactured with face and back plies of different species groups shall 
be identified by the face species group number.  Sanded panels with 
Performance Categor y greater than 3/8   that are manufactured with face and 
back plies of different species groups shall be identified by the larger numbered 
species group, except that sanded panels with C or D grade backs shall be 
permitted to be identified by the face speci es group number if backs are no more 
than one species group larger in number than the face and are 3.2 mm (1/8  inch) 
or thicker before sanding.  A class number as provided in Section 5.6.4 shall be 
used in lieu of a species group number to identify concret e form panels and a 
span rating shall be used for unsanded and touch -sanded grades as provided for 
in Section 5.8.5.  
 
(b) Either “Exposure 1” or “Exterior” Bond Classification  — Panels not fully 
satisfying Exterior requirements shall be identified as "Exposure 1." The panel 
mark shall include the Exterior or Exposure 1 bond classification.   Any further 
reference to adhesive bond, including those which imply premium performance 
or special warranty by the manufacturer, as well as manufacturer's proprietar y 
designations, shall be separated from the grademarks or trademarks of the 
testing agency by not less than 152 mm (6 in).  
 
(c) The grade name or the grade of face and back veneers or a mark of a qualified 
inspection and testing agency.  If identified by s uch a mark, the product 
specification shall be available from the qualified inspection and testing agency 
whose mark appears on the panel.  MDO and HDO panels with one working face 
shall include “One Working Face” or “1S” within the grade declaration. MDO a nd 
HDO panels with two working faces may include “Two Working Faces” or “2S” 
within the grade declaration.  
 
(d) The symbol “PS 1 -0919” signifying conformance with this Standard.  
 Formatted:  List Paragraph,  Indent:  Left:  0.56",  Hanging:  
0.44",  Numbered  + Level:  3 + Numbering  Style:  a, b, c, … +
Start at: 1 + Alignment:  Left + Aligned  at:  1.5" + Tab after:  
1.75" + Indent  at:  1.75",  Tab stops:  Not at  1.75" 
51 
 (e) The panel fractional Performance Category  (see section 5.10.2) and term 
“Performance Category” or abbreviation ( i.e., PERF CAT, CAT or Category)  shall 
be labeled on the panel. In addition, the thickness in 1000ths  of an  inch within the 
permitted tolerance for the Performance Category shall be labeled on the panel. 
See Appendix D for a table of re commended  Thickness  label s. 
 
(f) The designation “Butt -Jointed Center” for those panels manufactured with butt 
joints in center plies in accordance with Section 5.8.  
7.4 Voiding marks  
Panels originally marked as conforming to this Standard but subsequently rejected as not 
conforming thereto shall have any reference to the Standard obliterated or voided by the 
manufacturer as follows:  
 
Shop panels shall be plainly marked by means of a 102 mm by 127 mm (4 in x 5 in) minimum 
size mark carrying the legend "Shop -cutting panel — all other agency marks void."  (See 
Section 2. 535.4.) 
 
Other panels rejected as not conforming shall be plainly identified by a mark placed next to, and 
be no less prominent than the original mark, carrying the legend, “REJECT – All other agency 
marks void”.  
 
 
No reference shall be made to this Standard in th e certification or grade trademarking of panels 
not conforming to all of the applicable provisions of this Standard.  
8 EFFECTIVE DATE  
 
The effective date of this Standard is December 31, 2009 (TENTATIVE TBD).  As of the effective 
date, reference to PS 1 -09 19 shall be permitted in contracts, codes, advertising, invoices, 
product labels, and the like, but no product shall be advertised or represented in any manner 
which would imply or tend to imply approval or endorsement of that product by the National 
Institu te of Standards and Technology, the Department of Commerce, or by the Federal 
Government.  
9 STANDING COMMITTEE  
A Standing Committee for PS 1 -09 19 will be  appointed to be responsible for interpretation and 
for consideration of future proposals for amendments  and revisions to the Standard.  The 
names of the members are available from the Committee’s Secretariat:  Standards Coordination 
and Conformity Group, Standards Services Division, National Institute of Standards and 
Technology, 100 Bureau Drive, MS 2100, Gaithersburg, MD  20899 -2100.  Comments 
regarding the Standard and suggestions for its amendment or revision may also be sent to this 
address or contact NIST at http://ts.nist.gov/ssd.  
 
Issues regarding interpretation or implementation of the Standard and third-party quality 
assurance policies and procedures shall be considered by a Standard Implementation Review 
Subcommittee as appointed by the Standing Committee.  A request to consider such issues 
shall be made  in writing to the Secretariat of the Standin g Committee (NIST), who will bring it to 
the attention of  the Standing Committee.  Formal operating procedures developed for the Formatted:  Font: 11 pt 
52 
 Subcommittee shall be subject to approval by NIST.  Any recommended actions by the 
Subcommittee will be reported to the Standin g Committee for their consideration and action.  
 
   
53 
 Appendix A.  Species Grouping (mandatory)  
A1 General  
Product Standard PS 1  has included provisions for species grouping since the inception of PS  1 
in 1966.  Prior to PS 1 -66, U.S. plywood was manufactured in accordance with three regional 
plywood standards, Commercial Standard CS45 -60 for Douglas -fir Plywood, Commercial 
Standard  CS 122 -60 for Western Softwood Plywood and Commercial Standard CS 269 -63 for 
Southern Pine Plywood.  Grouping of wood species on the basis of similar mechanical 
properties in order to provide needed simplification in product manufacture, design and 
specif ication became possible with the advent of ASTM D 2555, Methods for Establishing Clear 
Wood Strength Values .  
A2 Grouping in practice  
Under the provisions of PS 1, it is possible to manufacture span rated plywood Sheathing and 
Single -Floor on the basis of the species group and plywood construction.  Similarly, the plywood 
group rating or plywood classification of non -span rated plywood may be determined by the 
species group and plywood construction.  PS 1 -83 introduced the provisions of determining 
span rat ings on the basis of performance testing.  PS 1 -95 included a performance -based 
method for evaluating new species not listed in Table 1, made desirable because of the 
changing available timber resource for plywood production.  
A3 Species grouping  
Wood speci es in Table 1 are grouped on the basis of mechanical properties.  Because bending 
stiffness and bending strength are the most important properties for many plywood uses, 
species groups were initially set up first on the basis of bending stiffness and secon d on the 
basis of bending strength.  Past practice of the PS 1 Standing Committee has been to add new 
species to the highest existing group so long as none of the existing group properties 
assignments provided in Table A1 are reduced by the addition.  
A3.1  Assignment of a species group shall be as follows:  
 
(a) Obtain average and standard deviation data of the five important mechanical 
properties of clear, straight -grained solid wood of all species in each group in the 
green and dry condition.  The five prop erties are bending modulus of elasticity 
(MOE), bending modulus of rupture, compression parallel to grain, shear parallel 
to grain and compression perpendicular to grain.  Property data for North 
American woods must be included in ASTM D 2555 or must be de veloped by the 
U.S. Forest Service or by a recognized Canadian government Laboratory.  In 
addition, new data must be obtained using recognized statistical sampling of the 
entire growth range of the species.  Foreign species are classified using data 
from t he government laboratory in the respective country.  Table A2 provides the 
source of data used to classify non -North American species listed in PS  1.  For 
each of the five properties, the limiting property value that can be assigned to any 
group that inclu des that species is determined at the dry (12% for MOE, 15% for 
all other properties) and green moisture content.  
 
(b) The maximum assignable MOE value is either the species average increased by 
10% if volume data is available in ASTM D2555 or the species average if no 
volume data exists or if it is a foreign species.  
 
(c) The strength properties are calculated in one of the following three methods:  
Method A species in ASTM D 2555  
Max. Assignable = (species average/variability index) – 1.18 x species stand ard 
deviation  
  
54 
 Method B species in ASTM D 2555  
Max. Assignable = species average – 1.48 x species standard deviation  
Domestic species with no volume data and foreign species  
Max. Assignable = species average – 1.645 x species standard deviation  
 
The maximu m assignable property must meet or exceed all property values listed 
in Table  C1 for the species group in order to be assigned that group.  
 
(c) Assignment of a species group to Table 1 shall be approved by the 
Standing Committee.   (See Section 5.2.)  
 
TABLE A1.  CLEAR WOOD PROPERTY ASSIGNMENTS  
 
 
Species  
Group  MOE  
(million psi)  Strength Property (psi)  
Bending  Comp Par  Shear  Comp Perp  
Wet Dry Wet Dry Wet Dry Wet Dry Wet Dry 
1 1.483  1.857  5300  8064  2425  4123  665 855 193 354 
2 1.249  1.588  3662  6297  1833  3163  532 692 124 221 
3 1.047  1.310  3681  5985  1548  2662  524 652 123 212 
4 0.924  1.146  3483  5389  1570  2630  476 633 97 152 
5 0.748  1.100  2843  4345  1190  2187  387 542 73 132 
 Formatted 
55 
 TABLE A2.  SOURCE OF DATA USED TO CLASSIFY FOREIGN SPECIES IN PLYWOOD  
PRODUCT STANDARD PS 1  
 
Common Name or  
Trade Group  Scientific Name  Source of Data  
Group 1    
Apitong  Dipterocarpus spp.  FPL 125  
FPL 2242 (bearing only)  
Kapur  Dryobalanops aromatica  
D. lanceolata  
D. oblongifolia  Malayan Forest Service Trade Leaflet #34  
FPL 125  
Malayan Forest Service Trade Leaflet #34  
Keruing  Dipterocarpus spp.  
D. baudii  
D. caudiferus  
D. cornutus  
D. crinitus  
D. lowii  FPL 2242  
Malayan Forest  Service Trade Leaflet #34  
FPL 2242  
Malayan Forest Service Trade Leaflet #34  
Malayan Forest Service Trade Leaflet #34  
Malayan Forest Service Trade Leaflet #34  
Caribbean Pine  Pinus caribaea  FPL 125  
Ocote Pine  Pinus oocarpa  FPL 125  
Group 2    
Red Lauan  Shorea negrosensis  FPL 125  
FPL 2242 (bearing only)  
Tangile  Shorea polysperma  FPL 125  
FPL 2242 (bearing only)  
White Lauan  Pentacme contorta  FPL 125  
FPL 2242 (bearing only)  
Almon  Shorea almon  FPL 125  
FPL 2242 (bearing only)  
Bagtikan  Parashorea plicata  FPL 125  
FPL 2242 (bearing only)  
Mersawa  Anisoptera laevis  
A. marginata  Malayan Forest Service Trade Leaflet #34  
Malayan Forest Service Trade Leaflet #34  
Mayapis  Shorea squamata  FPL 125  
Meranti  Parashorea lucida  
Shorea acuminata  
S. singkawang  
S. curtisii  
S. dasyphylla  Malayan Forest Service Trade Leaflet #5  
Malayan Forest Service Trade Leaflet #34  
Malayan Forest Service Trade Leaflet #34  
Malayan Forest Service Trade Leaflet #34  
FPL 125  
 S. hemslevana  Malayan Forest Service Trade Leaflet #34  
 S. leprosula  
S. macroptera  Malayan Forest Service Trade Leaflet #34  
Malayan Forest Service Trade Leaflet #34  
 S. pauciflora  
S. platyclados  Malayan Forest Service Trade Leaflet #34  
Malayan Forest Service Trade Leaflet #34  
 S. rugosa  Malayan Forest Service Trade Leaflet #34  
Group 4    
Cativo  Prioria copaifera  FPL 125  
Yale Bulletin #98 Tropical Woods (bearing only)  
 
   
56 
 Appendix B.  Reinspection Practices (non mandatory)  
B1 General  
Based on industry practice, the following information is offered plywood purchasers:  
B2 Request for reinspection  
Any request by the buyer for the reinspection of any item or lot of plywood certified as 
conforming to this Standard shall be directed to the seller.  Lacking agreement of th e buyer and 
seller as to the settlement of a complaint, the purchase, sale, or shipment of plywood certified 
as conforming to this Standard shall be construed as involving agreement to submit such 
plywood to reinspection by the qualified inspection agency whose grademark was used.  
B3 Responsibility of the buyer  
A request for reinspection shall be made to the seller:  
 
For panel grade — within 30 days after arrival at the first point of receipt from the mill, if the 
grade of any item, as invoiced, is in doubt;  
 
For adhesive bond quality of Exterior panels — when delamination is visibly evident;  
 
For adhesive bond quality of Exposure 1 — within 6 months after arrival at first point of receipt 
from the mill if delamination is visibly evident;  
 
All plywood o f disputed grade shall be kept intact and properly protected from damage, 
deterioration and from direct exposure to moisture which could interfere with a fair reinspection.  
All plywood in question shall be held for a period not to exceed 30 days after the  date of request 
for reinspection.  Use by the buyer of any or all of the disputed stock within the 30 -day period 
shall constitute an acceptance of the used portion.  
B4 Responsibility of the seller  
A request for reinspection shall be promptly acknowledged  by the seller following receipt of the 
request.  
B5 Responsibility of the qualified inspection agency conducting the reinspection  
Should either the buyer or the seller wish to have a representative present at the reinspection, 
the agency conducting the rei nspection will provide all reasonable accommodation to facilitate 
that request. Any party wishing to witness the reinspection shall inform the agency of that desire 
at the time of the initial request for reinspection, and shall be responsible for any costs  they 
incur in order to attend. Costs incurred by the agency performing the reinspection shall be 
assessed as noted in Section B6.  
B6 Cost and assistance  
The expense of reinspection shall be borne by the seller if the item, lot, or shipment in dispute 
fails to pass the reinspection as provided for in Section B7.  If the plywood passes the 
reinspection, said expenses shall be borne by the buyer.  The buyer shall lend all reasonable 
assistance to facilitate the reinspection.  
B7 Reinspection procedures and set tlement  
B7.1  Condition of plywood  
All plywood designated as complying with this Standard shall be subject to reinspection in the 
white (unfinished) only, except that concrete -form material is permitted to have a priming coat of 
a release agent.  This requi rement does not apply to Exposure 1 or Exterior plywood when 
tested for adhesive bond quality.   
57 
 B7.2  Sampling for panel grade, size and thickness reinspections  
At buyer's or seller's option, grade, size, and thickness reinspections shall include all panels of 
an item whose conformance to this Standard is in dispute; however, agreement between the 
buyer and seller on a reduced basis for sampling is permitted provided at least 20% or 300 
panels, whichever is smaller and which represents only those items as inv oiced which are in 
dispute, are reinspected for conformance.  For reduced sampling, the quantity of panels 
selected from each disputed item shall be prorated according to the number of panels included 
in each item as invoiced.  Panels found to be below gra de or out of tolerance for size and 
thickness shall have improper grademarks obliterated and shall be remarked with appropriate 
designation with a special inspection mark registered by the qualified agency conducting the 
reinspection and applied by that ag ency's authorized representative.  
B7.3  Plywood panel grade, size and thickness reinspections  
If reinspection establishes that a disputed item is more than 5% below grade or out of 
dimensional tolerance for the product description as invoiced, that product fails to pass the 
reinspection and the nonconforming panels need not be accepted.  If a disputed product is 5% 
or less below grade or out of dimensional tolerance, it shall pass the reinspection and the 
disposition of the nonconforming panels shall be as a greed upon between buyer and seller.  In 
addition to the above 5% grade and dimensional tolerance, a 5% tolerance shall apply 
separately to the inner ply gap limitations, including the limitations applicable to the plugged 
crossband and jointed crossband, as set forth in section 5.8.1.  
B7.4  Sampling for adhesive bond quality reinspections  
For test purposes, twenty panels, or 5% of the panels, whichever is less, shall be selected at 
random from the item, lot, or shipment which is in dispute.  The number of p anels required is 
calculated by applying the "percent panels" to the lot size and converting part panels to whole 
panels by using a rounding procedure where 0.01 to 0.49 parts are considered to be the smaller 
whole number, while 0.50 to 0.99 parts are cons idered to be the larger whole number.  These 
panels shall be selected from locations distributed as widely as practicable throughout the 
material being sampled.  When an item, lot, or shipment involves panels with different adhesive 
bond requirements as pr ovided for in 5.7, testing and evaluation shall apply separately to each 
category.  Sampling of Exposure 1 plywood or Exterior plywood shall be prorated on the basis 
of ratio of their volume to total volume (i.e., for shipment containing 50% Exterior, 10 E xterior 
panels shall be selected), but in no case shall less than 10 panels of each type or adhesive 
quality be selected.  Shipments of Exposure 1 plywood shall be sampled in the same manner as 
Exterior plywood.  
 
From each of five of the panels selected, a specimen 140 mm by 203 mm (5 -1/2 in x 8  in) shall 
be cut and tested as described in Section 6.1.3.4.  
B7.5  Plywood adhesive bond quality reinspections  
Reinspection of the unused panels in the disputed item, lot, or shipment shall be carried out 
following the procedures set forth in Section 6, "Specimen Preparation and Testing," and 
Section B7.4.  If the reinspection tests establish that the adhesive bond quality of the panels 
does not meet the requirements of Section 5.7, as applicable, the item,  lot, or shipment shall fail 
to pass the reinspection and is not required to be accepted by the buyer.  If the adhesive bond 
quality requirements are met, the item, lot, or shipment shall pass the reinspection and the 
buyer shall accept the item, lot, or s hipment as invoiced, except that the buyer is not required to 
accept any delaminated Exterior plywood or overlaid panels.  
  
58 
 Appendix C.  General Information and Comments On Current Edition (non mandatory)  
C1 Current edition, PS 1 -09 that became effective December 31, 2009  
The Standing Committee for PS 1 initiated a thorough review of PS 1 -07 in early 2009 due in 
part to consumer complaints  that indicated that  panels were out of compliance to provisions of 
NIST Handbook 130 and 133 dealing  with packaging and labeling.   
 
The consensus review process, which allowed for discussions and resolution of points of 
difference, moved at a steady pace.  This resulted in some noteworthy changes to the Standard 
some of which are highlighted as follows:  
 
C1.1  Labeling of panel thickness  
 
In response to consumer complaints regarding thickness labeling being out of compliance with 
NIST Handbook 130 and 133, the standard was re vised to create a Performance Category 
based on customary thickness notation s used in U.S. model building codes. In addition, p anel 
labeling requirements was changed to require the Performance Category and decimal thickness 
representation.  
C1.2  Formaldehyd e appendix  
 
In response to national and international regulations of formaldehyde emissions from some 
wood products, an appendix was added to review those regulations with respect to PS 1 
plywood.  
C1.3  Environmental attributes and green building  rating  systems  
 
An appendix was added to review environmental attributes of PS 1 plywood with respect to 
various  green building rating systems.  
C1.4  Technical revisions  
 
A review of technical provisions and termi nology led to various changes to reflect industry 
practice.  
C12 History of the project  
On October 1, 1965, the American Plywood Association (now APA - The Engineered Wood 
Association) submitted to the National Bureau of Standards (now the National Institute of 
Standards and Technology) a draft of a proposed Commercial Standard on softwood pl ywood, 
with a request that it be processed as a revision and consolidation of Commercial Standards 
CS 45-60 Douglas Fir Plywood , CS 122 -60 Western Softwood Plywood , and CS 259 -63 
Southern Pine Plywood . On November 1, 1966, Product Standard PS 1 -66 Softwood  Plywood, 
Construction and Industrial  became effective.  It was the first Voluntary Product Standard 
developed under new Department procedures, issued on November 16, 1965, for development 
of Voluntary Product Standards.  
 
Since 1966, there have been five six revisions to the Standard:  
C2.1  PS 1 -74 Construction and Industrial Plywood  became effective August 1, 1974   
Among other revisions, this version added over 20 species, primarily Southeast Asian 
hardwoods, to Table 1.  
  
59 
 C2.2  PS 1 -83 Construction and In dustrial Plywood became effective December 30, 1983   
This version added performance -based test methods and criteria for span rated applications.  
C2.3  PS 1 -95 Construction and Industrial Plywood  became effective September 7, 1995  
This version included the incorporation of a performance -based method for evaluating plywood 
manufactured with species not listed in Table 1, made desirable because of the changing 
available timber resource for plywood production.  The revisions included the elimination of 
Structur al II panel grades from the Standard because this product had rarely been 
manufactured since it was first introduced in PS 1 -66. 
C2.4  PS 1 -07 Structural Plywood  beca me effective February 26, 2007  
This version revised several sections of the standard to bet ter represent the production and 
trade specifications for the products. These included a change to the title of the standard, 
elimination of the interior and intermediate bond types, revisions to the overlaid plywood 
designations and addition  of an appendi x to detail the process for species grouping.  
 
C2.5 PS 1 -09 Structural Plywood  became effective  May 2010  
In response to consumer complaints regarding thickness labeling being out of compliance with 
NIST Handbook 130 and 133, the standard was revised to cr eate a Performance Category 
based on customary thickness notations used in U.S. model building codes. In addition, panel 
labeling requirements was changed to require the Performance Category and decimal thickness 
representation. Nonmandatory Appendices wer e added to provide recommended labeling and 
to provide guidance on quantity representations on bundles.  
 
In addition, nonmandatory Appendices were added to describe formaldehyde emission 
characteristics of PS 1 panels and how PS 1 panels align with various green building 
specifications.  
 
C2.6  Current edition, PS 1 -19 that became effective TBD  
 
After considerable technical review by members of the PS 1 Standing Committee, the standard 
was revised to address the following technical and informational a spects. Additional details were 
added regarding measurement of dimensions. The term “sized for spacing” was added to denote 
panels that are sized for compatibility to recommended application for construction uses.  
 
Other technical and editorial revisions were made to reflect industry practices, including:  
• Simplification of the Appendix on labeling  
• Deletion of the Appendix on Green Building Provisions  
• Revised definition of qualified testing and inspection agency  
• Added abbreviations commonly used for labeling  
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60 
 Appendix D .  (non mandatory ) 
D1 Recommend t hickness labels   
 
Section 5.10.2 specifies thickness tolerances and Performance  Categories for plywood grades . 
Secion  7.3.e specifies that the panels shall be labeled with a thickness label in 1000ths of an 
inch and that labeled quantity shall be within the minimum and ma ximum thickness specification 
for that Performance Category. Table D1 and Table D2 present recommende d thickness labels.  
D2 Regulations on labeling  
 
See Appendix E for discussion of regulations dealing with labeling.  
 
TABLE  D1.  RECOMMENDED THICKNESS LABELING FOR UNSANDED,  
TOUCH SANDED AND OVERLAID PANELS  
 
 Thickness Requirements for  
Unsanded, Touch Sanded and Overlaid Grades1 
Performance  
Category2 Minimum Thickness  
in. (mm)  Maximum Thickness  
in. (mm)  Recommended  
Thickness  Label(3) 
1/4 PERF CAT  0.219 (5.56)  0.281 (7.14)  Thickness .225 IN.  
11/32 PERF CAT  0.313 (7.94)  0.375 (9.53)  Thickness .322 IN. 
3/8 PERF CAT  0.344 (8.73)  0.406 (10.32)  Thickness .354 IN.  
 7/16 PERF CAT  0.406 (10.32)  0.469 (11.91)  Thickness .418 IN.  
15/32 PERF CAT  0.438 (11.11)  0.500 (12.70)  Thickness .451 IN.  
 1/2 PERF CAT  0.469 (11.91)  0.531 (13.49)  Thickness .483 IN.  
9/16 PERF CAT  0.531 (13.49)  0.594 (15.08)  Thickness . 547 IN.  
19/32 PERF CAT  0.563 (14.29)  0.625 (15.88)  Thickness .578 IN.  
5/8 PERF CAT  0.594 (15.08)  0.656 (16.67)  Thickness .609 IN.  
23/32 PERF CAT  0.688 (17.46)  0.750 (19.05)  Thickness .703 IN.  
3/4 PERF CAT  0.719 (18.26)  0.781 (19.84)  Thickness .734 IN.  
13/16 PERF CAT  0.781 (19.84)  0.844 (21.43)  Thickness .788 IN.  
7/8 PERF CAT  0.831 (21.11)  0.919 (23.34)  Thickness .849 IN.  
1 PERF CAT  0.950 (24.13)  1.050 (26.67)  Thickness .970 IN.  
1-1/8 PERF CAT 1.069 (27.15)  1.181 (30.00)  Thickness 1.091 IN.  
1-1/4 PERF CAT  1.188 (30.16)  1.313 (33.34)  Thickness 1.213 IN.  
1 1Thickness requirements for unsanded, touch sanded and overlaid panels are based on a tolerance of +/ - 0.8 
mm (1/32 in.) for panels with Performance Categories of 13/16 and less and +/ - 5% for panels with Performance 
Categories greater than 13/16 unless a closer tolerance is determined through qualification testing.  Inch units 
are presented as primary units due to customary practice i n the United States.  
Thickness requirements for sanded panels are based on a tolerance of 0.4 mm (1/64 in) for specified 
performance categories  of 3/4 and less and +/-3.0% for panels with a performance category greater  than 
3/4  unless a closer tolerance is determined through qualification testing.  Inch units are presented as primary 
units due to customary practice in the United States.   
2 Acceptable abbreviations are PERF CAT, CAT or Category.     
3 The recommended thickness label for categories less than 9/16 is 3% above the minimum.   The 
recommended thickness label for categories greater than or equal to 9/16 are the minimum values for 
sanded panels.    
 
 
   
61 
  
TABLE D2.  RECOMMENDED THICKNESS LABELING FOR SANDED PANELS  
 
 Thickness Requirements for  
Sanded Panels1 
Performance  
Category2 Minimum Thickness  
in. (mm)  Maximum Thickness  
in. (mm)  Recommended  
Thickness  Label3 
1/4 PERF CAT  0.234 (5.95)  0.266 (6.75)  Thickness .234 IN.  
11/32 PERF CAT  0.328 (8.33)  0.359 (9.139  Thickness .328 IN.  
3/8 PERF CAT  0.359 (9.13)  0.391 (9.92)  Thickness .359 IN.  
 7/16 PERF CAT  0.422 (10.72)  0.453 (11.51)  Thickness .422 IN.  
15/32 PERF CAT  0.453 (11.51)  0.484 (12.30)  Thickness .453 IN.  
 1/2 PERF CAT  0.484 (12.30)  0.516 (13.10)  Thickness .484 IN.  
9/16 PERF CAT  0.547 (13.8 9) 0.578 (14.68) Thickness . 547 IN.  
5/8 PERF CAT  0.609 (15.48)  0.641 (16.27)  Thickness .609 IN.  
23/32 PERF CAT  0.703 (17.86)  0.734 (18.65)  Thickness .703 IN.  
3/4 PERF CAT  0.734 (18.65)  0.766 (19.45)  Thickness .734 IN.  
13/16 PERF CAT  0.788 (20.02)  0.837 (21.26)  Thickness .788 IN.  
7/8 PERF CAT  0.849 (21.56)  0.901 (22.89)  Thickness .849 IN.  
1 PERF CAT  0.970 (24.64)  1.030 (26.16)  Thickness .970 IN.  
1-1/8 PERF CAT 1.091 (27.72)  1.159 (29.43)  Thickness 1.091 IN.  
1-1/4 PERF CAT  1.213 (30.80)  1.288 (32.70) Thickness 1.213 IN.  
1 Thickness requirements for sanded panels are based on a tolerance of +/- 0.4 mm (1/64 in) for specified 
performance categories of 3/ 4 and less and +/- 3.0% for panels with a perform ance category greater than 3/4  unless 
a closer tolerance is determined through qualification testing.  Inch units are presented as primary units due to 
customary practice in the United States.  
 
2 Acceptable ab breviations are PERF CAT, CAT or Category.  
 
3 Recommended thickness labels for performance categories are based on the minimum permissible thickness for 
that category . 
 
 
   
62 
  
Appendix E.  Labeling Guidelines Based on the Uniform Packaging and Labeling 
Regula tions of NIST Handbook 130 v2009 and  Handbook 133  (non mandatory ) 
E1 Summary  
E1.1 When intended for sale or distribution, the labeling of the panels should meet the 
requirements of the Uniform Packaging and Labeling Regulation. This section provides 
references to standards applicable to labeling and packaging.  
E2 Background  
E2.1 The Nat ional Institute of Standards and Technology of the U.S. Department of 
Commerce (“NIST”) promotes the development of standards to be applied across industry and 
supports the publishing of NIST Handbook 130, “Uniform Laws and Regulations in the areas of 
legal metrology and engine fuel quality .” NIST Handbook 130 is a compilation of the latest 
uniform laws and regulations regarding packaging and labeling requirements adopted by the 
National Conference on Weights and Measures, Inc. (“NCWM”) and is intended to r epresent 
standards to be adopted into law by the weights and measures jurisdictions of the United 
States.   
E2.2 Procedures used by Weights and Measures inspectors are included in NIST Handbook 
133, “Checking the Net Contents of Packaged Goods”  
E2.3 For information, a complete copy of the most recent version of NIST Handbook 130 and 
133 are  available at : 
 https://www.nist.gov/publications/  
 
E1.1 
When intended for sale or distribution, the labeling of the panels should meet the requirements 
of the Uniform Packaging and Labeling Regulation. This section provides guidance on the 
requirements applicable to wood panels.  
E2 Background  
E2.1  
The National Institute of Standards and Technology of the U.S. Department of Commerce 
(“NIST ”) promotes the development of standards to be applied across industry and supports the 
publishing of NIST Handbook 130, “ Uniform Laws and Regulations in the areas of legal 
metrology and engine fuel quality ”. NIST Handbook 130 is a compilation of the latest uniform 
laws and regulations regarding packaging and labeling requirements adopted by the National 
Conference on Weights and Measures, Inc. (“ NCWM ”) and is intended to represent standards to 
be adopted into law by the weights  and measures jurisdictions of the United States.   
E2.2  
Of the weights and measures jurisdictions of the United States (including, the 50 states, 
Washington DC, Puerto Rico and the Virgin Islands) with respect to the Uniform Packaging and 
Labeling Regula tion, (i) 19 have adopted the most current version of NIST Handbook 130, (ii) 29 
have adopted a prior version of NIST Handbook 130, (iii) four have laws and regulations in 
place that are not based on NIST Handbook 130 and (iv) one has no specific laws or r egulations 
in this regard.  Formatted:  Font: 11 pt
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63 
 E2.3  
This appendix provides a summary of NIST Handbook 130 provisions relevant to wood panels, 
with specific references to sections of the 2009 version.  This summary is not intended to be 
comprehensive, but is offered as guidan ce.  For additional information, a complete copy of the 
most recent version of NIST Handbook 130 is available at 
http://ts.nist.gov/WeightsAndMeasures/Publications.  
E3 Scope and d efinitions  
E3.1  
Except for packages intended for export, the Uniform Packaging and Labeling Regulation of 
NIST Handbook 130 applies to consumer and non -consumer packages.  
E3.1.1  Consumer package  
“[A] package that is customarily produced or distributed for sale through retail sales agencies or 
instrumentalities for consumpti on or use by individuals for the purposes of personal care or in 
the performance of services ordinarily rendered in or about the household or in connection with 
personal possessions .”  (See  Section 2.2 of the Uniform Packaging and Labeling Regulation).  
E3.1.2  Non-consumer p ackage  
“Any package other than a consumer package, and particularly a package intended solely for 
industrial or institutional use or for wholesale distribution .”  (See  Section 2.3 of the Uniform 
Packaging and Labeling Regulation).  
E3.2  
The requirements of the Uniform Packaging and Labeling Regulation set forth in NIST 
Handbook 130 are to be set forth generally on labels and/or principal display panels.  
E3.2.1  Label  
“Any written, printed, or graphic matter affixed to, applied to, attached to, blown into, formed, 
molded into, embossed on, or appearing upon or adjacent to a consumer commodity or a 
package containing any consumer commodity, for purposes of branding, identi fying, or giving 
any information with respect to the commodity or to the contents of the package, except that an 
inspector’s tag or other nonpromotional matter affixed to or appearing upon a consumer 
commodity shall not be considered a label requiring the repetition of label information required 
by this regulation.”  (See Section 2.5 of the Uniform Packaging and Labeling Regulation).  
 
Note: For the purpose of structural wood panels, the “label” encompasses information that is 
attached to or affixed to the p anel or to the panel bundle prior to shipping from the mill.  At the 
retail level, the label may encompass information that is adjacent to the panels.   
E3.2.2  Principal display panel  
“[t]hat part, or those parts, of a label that is, or are, so designed as  to most likely be displayed, 
presented, shown, or examined under normal and customary conditions of display and 
purchase.  Wherever a principal display panel appears more than once on a package, all 
requirements pertaining to the ‘principal display panel’  shall pertain to all such ‘principal display 
panels.”  (See Section 2.7 of the Uniform Packaging and Labeling Regulation).  
E4 Declaration of identity and r esponsibility  
E4.1  
The package of wood panels must be labeled with the product identity and with the panel 
producer.  
E4.2 Product identity  
The name of the panel product should be included on the principal display panel for consumer  
64 
 packages and on the outside of the package  for non -consumer packages.  ( See Sections 3.1 
(consumer) and 4 (non -consumer) of the Uniform Packaging and Labeling Regulation).  The 
product identity for consumer packages should be parallel to the base on which the package 
rests as it is designed to be displayed.  ( See Section 3.1.1 of the Uniform Packaging and 
Labeling Regulation).  
E4.3 Product responsibility  
The company name should be included on the label of the package. ( See Section 5 of the 
Uniform Packaging and Labeling Regulation).  
 
E4.3.1   
The c ompany identification on the label should include city, state and zip code of the company. 
(See Section 5 of the Uniform Packaging and Labeling Regulation).  
E5 Declaration of q uantity  
E5.1  
The following guidance on Declaration of Quantity is based on the requirements for “Consumer 
Packages”.  Deviations based on “Non -Consumer Packages” are provided in [brackets].  
E5.2  
Quantity should be expressed in terms of count combined with appropriate declarations of the 
weight, measure and/or size of the individ ual units unless a declaration of count alone is fully 
informative but, if there exists a firmly established general consumer usage and trade custom 
with respect to the terms used in expressing a declaration of quantity of a particular commodity, 
such decl aration of quantity may be expressed in its traditional terms if such traditional 
declaration gives accurate and adequate information as to the quantity of the commodity.  ( See 
Sections 6.4 and 6.4.1 of the Uniform Packaging and Labeling Regulation).  [There is n o stated 
requirement regarding additional measurements other than count for non -consumer packaging.  
In other words, count or established trade custom is the requirements for non -consumer 
packages.  (See Section 7.3 of the Uniform Packaging and Labe ling Regulation)].  
E5.3 General Rules  
 
E5.3.1   
The size quantity declaration must be expressed in metric system units (meter (m), centimeter 
(cm) or millimeter (mm)) and in inch -pound system units (yard (Yd), foot (ft), inch (in)).  ( See 
Sections 6.1 (Note 3), 6.5, 6.5.1, 6.7 and 6.7.1 of the Uniform P ackaging and Labeling 
Regulation).  [The same rules apply to non -consumer packages except that either or both the 
metric system units and the inch -pound system units may be used. (See Sections 7.1 (Note 6), 
7.4, 7.4.1, 7.5 and 7.5.1 of the Uniform Packagin g and Labeling Regulation).]  
 
X5.3.2 The size quantity should be expressed in terms of the largest whole unit.  ( See Section 
6.2 of the Uniform Packaging and Labeling Regulation).  [The same rules apply to non -
consumer packages.  See Section 7.2 of the Uniform Packaging and Labeling Regulation.]  
 
o Remainders for the metric system units should be expressed as decimals. ( See 
Section 6.2 of the Uniform Packaging and Labeling Regulation).  [The same rules 
apply to non -consumer packages.  See Section 7.2 of th e Uniform Packaging and 
Labeling Regulation.]  
o If less than 1 m, then length measure is expressed in terms of cm or mm.  See 
Section 6.6.1(a) of the Uniform Packaging and Labeling Regulation.  [No comparable 
rules for non -consumer.]  
o If greater than 1 m, the n length is expressed in m with decimal fractions.  See 
Section 6.6.2(a) of the Uniform Packaging and Labeling Regulation.  [No comparable  
65 
 rules for non -consumer.]  
o Metric system measurements should go 3 digits out except where the quantity is 
below 100 mm or cm, where it may be shown in 2 digits.  In any case, any final zero 
appearing to the right of the decimal point need not be shown.  See Section 6.5(g) of 
the Uniform Packaging and Labeling Regulation.  [Same rules for non -consumer 
packages.  See Section  7.4 of the Uniform Packaging and Labeling Regulation.]  
o Remainders for the inch -pound system units should be expressed in common 
fractions or decimal fractions of the largest whole unit or in the next smaller whole 
unit with any further remainder in terms of common or decimal fractions of the 
smallest unit present.  See Section 6.2 of the Uniform Packaging and Labeling 
Regulation.  [Same rules for non -consumer packages.  See Section 7.2 of the 
Uniform Packaging and Labeling Regulation.]  
o If less than 1 ft, t hen length is expressed in terms of in.  See Section 6.8.1(a) of the 
Uniform Packaging and Labeling Regulation.  [No comparable rules for non -
consumer.]  
o If greater than 1 ft, then length is expressed in terms of the largest whole unit (Yd or 
ft) with any r emainder expressed in inches and fractions of the inch or in fractions of 
the ft or Yd, except that it shall be optional to include a statement of length in terms 
of inches.   See Section 6.8.2(a) of the Uniform Packaging and Labeling Regulation.  
[No compa rable rules for non -consumer.]  
o A common fraction is reduced to its lowest term.  A decimal fraction shall not be 
carried out more than 3 decimal places.  See Section 6.11 of the Uniform Packaging 
and Labeling Regulation.  [No comparable rules for non -consu mer.]  
 
E5.3.2  Rules specific to bi -dimensional commodities [No comparable rules for non -
consumer.]  
 
o Must be expressed in both metric and inch -pound units. No declaration of area is 
required for commodities for which the length and width measurements are critical in 
terms of end use if such commodities clearly present the length and width 
measurements on the label.  ( See Section 6.9 of the Uniform Packaging and 
Labeling Regulation).   
o If the area is 37.1  dm2 (4 ft2) or more, in terms of th e length and width, in terms of the 
largest whole unit, provided bi -dimensional commodities with a width of 10  cm (4  in) 
or less, the inch -pound statement of width shall be expressed in terms of linear 
inches and fractions thereof, and length shall be expr essed in the largest whole unit 
(yard or foot) with any remainder in terms of fractions of the yard or foot, except that 
it shall be optional to express the length in the largest whole unit followed by a 
statement of length in inches or to express the leng th in inches followed by a 
statement of length in the largest whole unit.  An inch -pound dimension of less than 
2 ft may be stated in inches.  ( See Section 6.9(c) of the Uniform Packaging and 
Labeling Regulation).   
  Examples : 
5 cm x 9.14 m (2 in x 10 yd) , or 
5 cm x 9.14 m (2 in x 10 yd) (360 in), or  
5 cm x 9.14 m (2 in x 360 in) (10 yd),  
E5.3.3   
The required quantity declaration may be supplemented by one or more declarations of weight, 
measure, or count, such declaration appearing other than on a principal display panel.  Such 
supplemental statement of quantity of contents shall not include any term qualifying a unit of 
weight, measure, or count that tends to exaggerate the amount  of commodity contained in the 
package (e.g., “giant”  quart, “larger” liter, “full” gallon, “when packed,” “minimum,” or words of 
similar import).  ( See Section 6.12 of the Uniform Packaging and Labeling Regulation).  [No 
such provision applies to non -consumer packag es.]  
66 
  
E5.3.4    
In no event, may any declaration of quantity be qualified by the addition of the words “when 
packed,” “minimum,” or “not less than” or any words of similar import (e.g., “approximately”), nor 
shall any unit of weight, measure, or count be qu alified by any term (such as “jumbo,”, “giant,” 
“full,” or the like) that tends to exaggerate the amount of commodity.  ( See Section 6.14 of the 
Uniform Packaging and Labeling Regulation).  [No such provision applies to non -consumer 
packages.]  
E6 Prominenc e and p lacement  
 
E6.1 General  
All information required to appear on a consumer package shall appear thereon in the English 
language  and shall be prominent, definite, plain, and conspicuous as to size and style of letters  
and numbers  and as to color of letters and numbers in contrast to color of background.  Any 
required i nformation that is either in hand lettering  or hand script  shall be entirely clear and 
equal to printing in legibility.  ( See Section 8.11 of the Uniform Packaging and Labeling 
Regulation). [All information requir ed to appear on a non -consumer package shall be definitely 
and clearly stated thereon in the English language .  Any required information that is either in 
hand lettering  or hand script shall be ent irely clear and equal to printing in legibility.  ( See 
Section 9.1 of the Uniform Packaging and Labeling Regulation).]   
 
E6.2 Location  
The declaration or declarations of quantity of the contents of a package shall appear in the 
bottom 30  % of the principal display panel or panels.  ( See Section 8.1.1 of the Uniform 
Packaging and Labeling Regulation).   
 
E6.3 Style of type and l ettering  
The declaration or declarations of quantity shall be in such a style of type or lettering as to be 
boldly, clearly , and conspicuously presented with respect to other type, lettering, or graphic 
material on the package.  ( See Section 8.1.2 of the Uniform Packaging and Labeling 
Regulation).   
 
E6.4 Color c ontra st 
The declaration or declarations of quantity shall be in a  color that contrasts conspicuously with 
its background.  ( See Section 8.1.3 of the Uniform Packaging and Labeling Regulation).   
 
E6.5 Free a rea 
The area surrounding the quantity declaration shall be free of printed information:  (a) above 
and below, by a  space equal to at least the height of the lettering in the declaration, and (b) to 
the left and right, by a space equal to twice the width of the letter “N” of the style and size of 
type used in the declaration.  ( See Section 8.1.4 of the Uniform Packagin g and Labeling 
Regulation).  
 
E6.6 Parallel quantity d eclaration  
The quantity declaration shall be presented in such a manner as to be generally parallel to the 
declaration of identity and to the base on which the package rests as it is designed to be 
displayed.  ( See Section 8.1.5 of the Uniform Packaging and Labeling Regulation).   
 
E6.7 Height and p roportion of numbers and l etters  
A Table 1 sets forth minimum heights of numbers and letters based upon the area of the 
principal display panel. The minim um height of numbers and letters for an area of 400 in2 or 
greater is ½ in.  The height of each number of a common fraction must meet ½ the minimum 
height standard.  No number or letter may be more than 3X as high as it is wide.  ( See Sections 
8.2.1 and 8. 2.2 of the Uniform Packaging and Labeling Regulation).   
67 
  
 
   
68 
 Appendix F.  Wood Structural Panels as Green Building Materials  (non mandatory ) 
F1 Overview  
There is a growing emphasis in North America to recognize the importance of protecting the 
environment.  This is commonly referred to as being “green” and has resulted in a need to 
increase the awareness of wood as an environmentally friendly or green building material.  
Wood structural panels, as members of the broader wood products “family”, h ave numerous 
green attributes and are considered to be environmentally friendly.  
F2 Green attributes of w ood 
Solar energy:   powered by solar energy collected by the tree’s leaves, carbon dioxide extracted 
from the atmosphere is combined with water and nutrients absorbed through the tree’s roots to 
form a composite of hollow cellulose fibers bound in a matrix of lignin by phot osynthesis.  
Renewable:  as mature trees are harvested they are replaced by younger trees and the wood 
resource is renewed.  This natural renewal can continue indefinitely as long as there is an 
ample source of water, carbon dioxide and sunlight.  
Sustainabl e: through responsible forest management the forest resource can be sustained at 
levels far exceeding their harvesting.  Responsible forest management is the key to minimizing 
adverse environmental impacts associated with the extraction of timber from fore sts. (Society of 
American Foresters (SAF), www.safnet.org ) 
Embodied Energy:   studies have shown that wood has low embodied energy  compared to most 
other structural materials.  The energy consumed in managing forests, harvesting trees, milling 
timber into various end products and transporting the finished wood products to job sites is 
relatively small.  (CORRIM, www.corrim.org)  
Carbon Sequestration:  scientific evidence suggests that increasing levels of carbon dioxide in 
the atmosphere is one cause of accelerated climate change.  Trees absorb CO2 from the 
atmosphere through photosynthesis, storing it as carbon in their organic matter and 
releasing the remaining oxygen back into the atmosphere. On average a typical tree 
absorbs, through photosynthesis, t he equivalent of 56 pounds of carbon dioxide for 
every cubic foot of growth, while producing the equivalent of 45 pounds of oxygen. 
(adapted from Edinburgh Centre for Carbon Management ) 
 
Life Cycle Assessment:    Life Cycle Assessment (LCA) is important because it quantifies how a 
building product or system affects the environment during each phase of its life: extraction, 
production, installation, use and disposal or re -use.  (International Organization for 
Standar dization, ISO 14040, 14042 and 14043)   
Several CORRIM reports address many of these attributes and provide extensive scientific data 
supporting the relatively minimal impact that producing wood products has on the environment . 
F3 Sustainable forest m anagement programs  
There are four generally recognized sustainable forest management programs with the 
approximate amount of acres covered in North America for each shown in parentheses:   
The Forest Stewardship Council (FSC) , (82 million acres) www.fscus.org  
The Sustainable Forestry Initiative® (SFI),  (143 million acres)  www.sfiprogram.org   
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 The Canadian Standards Association (CAN/CSA -Z809) , (192 million acres)  www.csa -
international.org/product_areas/forest_products_marking   
The American Tree Farm System (ATFS)  (27 million acres)  www.treefarmsystem.org   
All of these sustainable forest management programs are intended to ensure that forestry is 
practiced in an environmentally responsible, socially beneficial, and economically viable way.  
The CSA, FSC, and SFI programs currently have criteria for on -product labeling of certified 
wood products.  Each has a system for manufacturing facilities to track the percentage of fiber 
that originates from certif ied forests.  
F4 Major green building r ating  systems  
To account for and quantify the effects of building construction on the environment, three major 
green building rating systems have evolved.  These are the:  
 
Green Building Initiative (GBI) Green Globes :  this is a rating system for new commercial 
building construction and has been approved as an ANSI Standard.  www.thegbi.org  
 
Green Building Standard : this is a program to rate residential construction and has been 
approved as an ANSI Standard with ICC and NAHB jointly sponsoring the standard.  
www.nahbgreen.org  
 
USGBC LEED™  which has four distinct rating programs including, LEED for New Construction; 
LEED™ for New Construction; L EED™ for Existing Buildings (Remodeling); LEED™ for 
Commercial Interiors and LEED™ for Homes.   www.usgbc.org/LEED  
 
Each of these programs considers the impact of various environmental considerations and 
assigns points accordingly to achieve a green rating threshold.   
 
While there are similarities in these rating systems there are also differences that can impact the 
wood products industry.  The GBI Green Globes and NAHB Green Building Standard both 
award points for wood being a renewable resource, for wood products harvested from any of the 
four forest certification programs and for using LCA to compare building materi als and systems. 
The USGBC  LEED™ program only awards points for products that are renewed within a 10 
year harvest cycle thus excluding most structural wood products, only awards points for wood 
products manufactured from FSC certified forests and does not  consider LCA as a science 
based evaluation tool.  
 
 
 
   
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 Appendix GF.  Formaldehyde ( non mandatory ) 
G1F1 General  
Formaldehyde is a simple naturally occurring chemical made of carbon, oxygen and hydrogen. 
It is produced by the human body and animals and plants. It is also formed by combustion and 
is an industrial chemical widely used in the manufacture of many consumer products.  
Background information on formaldehyde and health concerns related to elevated levels in 
indoor air can be found at www.epa.gov/ iaq/formalde.html.  
G2F2 Formaldehyde regulations  
G2F2.1  
There are no national or state regulations of formaldehyde emissions expressly stated for PS 1 
structural plywood. This is mainly due to the very low emission rates demonstrated by PS 1 
Structural P lywood.  
G2F2.2  
U.S. Department of Housing and Urban Development Rules and Regulations 24 CFR 3280 for 
manufactured housing includes § 3280.308 “Formaldehyde emission controls for certain wood 
products”, that deals with formaldehyde emissions from particl eboard and plywood. The 
regulations establish limits for formaldehyde emission levels and ongoing evaluation 
requirements as follows (underlined emphasis added):  
 
(b) Product certification and continuing qualification.   All plywood and particleboard materi als to 
be installed  in manufactured homes which are bonded with a resin system or coated with a 
surface finish containing formaldehyde, other than an exclusively  phenol -formaldehyde resin 
system  or finish, shall be certified by a nationally recognized testing laboratory as  complying 
with paragraph (a) of this section.  
 
PS 1 Structural Plywood is made  predominantly  with phenol -formaldehyde  adhesives . When 
made as such, it  is exempt  from the HUD re quirements.  
G2F2.3 California Air Resources Board (CARB) Air toxic Control Measure for 
Composite Wood Products (see: http://www.arb.ca.gov/research/indoor/formaldehyde.htm ) 
 
The CARB AT CM for Composite Wood was approved for implementation on January 1, 2009. 
The scope of the standard is particleboard, medium Density Fiberboard (MDF) and hardwood 
plywood. Section § 93120.1 “ Definitions” explicitly excludes PS 1 Structural Plywood and other 
structural wood products from the scope of the standard as follows (underlined emphasis 
added):  
 
(8) “Composite wood products” means hardwood plywood, particleboard,  and medium density 
fiberboard. “Composite wood products” does not  include hardboard,  structural plywood as 
specified in the “Voluntary  Product Standard - Structural Plywood” (PS 1 -07), structural panels 
as specified in the “Voluntary Product Standard – Performance Standard  for Wood -Based 
Structural -Use Panels” (PS 2 -04), structural  compos ite lumber as specified in “Standard 
Specification for  Evaluation of Structural Composite Lumber Products” (ASTM D 5456 -06), 
oriented strand board, glued laminated timber as specified in  “Structural Glued Laminated 
Timber” (ANSI A190.1 -2002),  prefabricated  wood I -joists as specified in “Standard Specification 
for Establishing and Monitoring Structural Capacities of Prefabricated  Wood I -Joists” (ASTM D 
5055 -05), finger -jointed lumber, or “composite  wood products” used inside of new vehicles as 
defined in sec tion 430  of the California Vehicle Code (excluding recreational vehicles), railcars, 
boats, aerospace craft, or aircraft.  
 
F2.4 National “Formaldehyde Standards for Composite Wood Act”  Formatted:  Indent:  Left:  0" 
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 The Formaldehyde Standards for Wood Composites Act was signed into law on July 7, 2010.   With respect 
to PS 1 panels, this law is identical to the CARB ATCM for Composite Wood (see Section F2.3). PS 1 
panels are exempt from the scope of the Formaldehyde Standards for Composite Wood Act. For further 
information see: https://www.epa.gov/  
 
G3F3 Formaldehyde emission from PS 1 Plywood  
G3F3.1  
Information on formaldehyde  emission from PS 1 panels is available from APA in Technical 
Note J330, “Formaldehyde and Engineered Wood Products” (see: www.apawood.org).  
Information on formaldehyde emission from PS 1 plywood is available from APA in report SPE -
1040, “ Structural Wood Panels and Formaldehyde .”