Plywood Grading Rules :Part 4 Hardwood Plywood Grading Guide from Columbia Forest

Plywood Grading Rules :Part 4 Hardwood Plywood Grading Guide from Columbia Forest

Decemver 27th,2018

PLYWOOD GRADING INFORMATION

Timber is a natural product and has an infinitely varying range of characteristics and appearances. The Hardwood Plywood and Veneer Association of America (HPVA) have created a set of rules called the Voluntary Standard for Hardwood and Decorative Panels commonly known as grading codes, which define allowable ranges of appearances and behavior for different species of hardwood plywood.

PLYWOOD GRADING STANDARDS

HARDWOOD PLYWOOD (DOMESTIC)

ANSI Plywood Grading Standards & Descriptions

FACE GRADE Applications BACK GRADE Description
A – Where excellent appearance is very important as in cabinets and furniture. 1 – 2 – Provide sound surfaces with all openings in the veneer repaired except for vertical worm holes not larger than 1/16″.
B – Where the natural characteristics and appearance of the species are desirable.
3 – Some open defects.
Repaired splits, joints, bark pockets, laps and knotholes can achieve a sound surface if specified by the buyer.
C – D – Provide sound surfaces but allow unlimited color variation. Repairs in increasing size ranges allowed respectively from C to D. Applications – where surface will be hidden or a more natural appearance is desired.
4 – Some open defects.
Knotholes up to 4″ in diameter are permitted. open splits, and joints limited by width and length.

PLYWOOD FACE GRADES

Red and White Oak – (Rotary-Cut) – (Plain-Sliced) – (Quarter-Cut)
Pin Knots & Small Burls Comb. Average Sound & Repaired Knots in Combination Repaired Knots Mineral Streaks Sap Blended Repaired Tapering Hairline Splits
A Max 12 (4 up to 1/4″) NO NO Slight 5% (1) Two 1/16″ x 6″
B Max 24 (16 up to 1/4″) 4 4 to 1/8″ Few to 8″ Up to 20% (2) Four 1/8″ x 8″
C No Limit 8 4 to 1/2″ Yes to 12″ Yes Four 3/16″ x 8″
(1) No sap allowed in Rift, Comb, and P/S; Allowed in Rotary White Oak.
(2) Rotary Red Oak; 10% Sap allowed in Rift, Comb, and P/S; Any Sap allowed in Rotary White Oak.

PLYWOOD FACE GRADES

Red and White Oak – (Rotary-Cut) – (Plain-Sliced) – (Quarter-Cut)
Pin Knots & Small Burls Comb. Average Sound & Repaired Knots in Combination Repaired Knots Mineral Streaks Sap Blended Repaired Tapering Hairline Splits
A Max 12 (4 up to 1/4″) NO NO Slight 5% (1) Two 1/16″ x 6″
B Max 24 (16 up to 1/4″) 4 4 to 1/8″ Few to 8″ Up to 20% (2) Four 1/8″ x 8″
C No Limit 8 4 to 1/2″ Yes to 12″ Yes Four 3/16″ x 8″
(1) No sap allowed in Rift, Comb, and P/S; Allowed in Rotary White Oak.
(2) Rotary Red Oak; 10% Sap allowed in Rift, Comb, and P/S; Any Sap allowed in Rotary White Oak.

PLYWOOD BACK GRADES

Sound Tight Knots Knotholes Repaired Knots Sound Tight Burls Mineral Sap Rough Cut Splits or Joints
1 Max 16 (Up to 1/4″) NO NO Yes Yes/Yes Two 8″ Dia. Areas NO
2 Max 16 (Up to 1/4″) All Repaired 8 to 1/2″ Yes Yes/Yes Yes Slight
3 Max 16 (1/2″ Up to 1-1/2″) All 3/8″ to 1″ No (1) Yes Yes/Yes Yes Two 8″ Areas
4 Yes Up to 4″ NO Yes Yes/Yes Yes 5% of Panel
LOP=Length of Panel
(1) May be Obtained Repaired, If specified

HARDWOOD PLYWOOD (IMPORTED)

Imported Plywood is graded with a face and back grade designation.

B/BB: Single piece face and back veneer. Face veneers are considered clear and free of defects with a light-uniform color. Back allows 3-6 color matched patches, which are oval in shape and egg sized. Inner cores are solid birch single piece veneers.

BB/BB: Single piece face and back. Both face and back veneers allow 3-6 small color-matched patches on average and some light mineral streaks. Tight pin knots may be present. Inner cores are solid single piece veneers.

BB/CP: Single piece face and back. The “CP” back veneers are downgraded from “BB” grade veneers, which allow for unlimited patches and sound knots, but does not allow for open defects. Inner cores are solid birch single piece veneers.

CP/CP: Single piece face and back. Face and back grade veneers allow unlimited sound knots and repaired splits and unlimited patches. The panel is sound both sides and designed for laminating.

C/C: Patches, open knots, and small veneer splits allowed. Veneer lap and small core voids permitted. This panel is not sanded and would be used for structural purposes.

SHOP GRADES: Shop panels are offered in the full 60” X 60” format in all of the grades listed above. Panels allow for 1-3 splits on the face veneer along one edge of the panel in lengths no longer than 10” and no wider than ¼”. Shop grades offered at a substantial discount to the “on grade” prices.

The explanation of grades listed above is a general overview.

An introduction from Ang Schramm

Trees are amazing. They provide us with shelter, warm our hearths, and shade us from the heat of the summer sun. But they also give us far more as they offer up their inner distinctiveness to serve us as one of the most functional and attractive of all materials for quality kitchen and bath cabinetry, fine furniture, architectural millwork, store fixtures, and wall furnishings, to name just a few.

Wood is a unique material for decorative applications in that by its very nature no two pieces can ever be exactly alike. Its appearance may be consistent for a given species within a broad and generalized range, but even wood from the same tree can vary in aesthetics and physical properties. Growth conditions such as geography and climate, availability of water and nutrients, adverse weather, genetics, pestilence, injury, competition for space, bacterial or viral infection, the presence of extraneous compounds contributing to the color of heartwood, the lighter color of sapwood, and the presence of limbs and their relationship to figure and knots, are but a few of the factors contributing to this phenomenon.

It is the purpose of this publication to help us give some order to this assortment of characteristics in a practical manner with an overview of the industry standard grading tables and other content, including veneer production, core options, and plywood manufacture. With a sound understanding of the inherent individuality of trees, we have the rare opportunity to make every project or job a signature work of art!

Our goal is to provide this information in a way that is easy to understand and that will give us a valuable tool to help enhance communication and ensure that all your expectations are met when you choose Columbia Forest Products’ PureBond® Hardwood Plywood.

Ang Schramm, Grading Guide, plywood

Ang Schramm

Director of Technical Services
Author of A Complete Guide to Hardwood Plywood and Face Veneer

Past Panel Products Director HPVA

Past Chair HPVA Technical Committee

Director and Instructor Columbia Forest Products University

 

Special thanks to   the following resource :

1.https://www.columbiaforestproducts.com/library/reference-guides/grading-guide/

2.http://www.hardwoodweb.com/pdf/catalogue_plywoodVeneers.pdf

3.www.ucfp.com/resources/hardwood_plywood/…/Columbia_Grading_Guide.pdf

4.https://www.andersonplywood.com/plywood-grading-information/

5.https://www.decorativehardwoods.org/

 

 

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