This is a plywood grading rule governed by "Hardwood Plywood and Veneer Association (HPVA)". It is used as a plywood grading standard in the USA.
- A Grade Face - The face on hardwood plywood should be matched for both grain and color. All veneer splices should be book-matched for a visually pleasing appearance. There should not be any abrupt changes in color or grain between the splices and will not permit sound knots, repaired knots or rough-cut veneer. It may allow slight mineral streak and/or vine marks. The number of defects such as pin knots or small burls varies according to the specie of veneer. This is the best face grade on plywood normally stocked and is often used for upper-end cabinetry, architectural millwork, and quality furniture.
- B Grade Face - The face on hardwood plywood should be matched for a pleasing color, but not necessarily for grain. B grade faces are generally very similar to A faces, but do allow some sound or repaired knots and some slight rough cut veneer. B grade faces will also allow slight mineral streak and vine marks and are often used by customers wishing to save a little money on plywood.
- C Grade Face - The face on hardwood plywood allows for unlimited pin knots and small burls. It also can contain repaired knots and sound knots, allow unlimited mineral and vine marks, and face should be a sound smooth face. A C face is used primarily on paint grade type panels, in lower-end case work, and for cabinet interiors in upper-end cabinetry.
- D Grade Face - The face on hardwood plywood is similar to C grade face, but will allow some rough cut veneer and a few more repaired and sound knots.
- 1 Back - It can contain up to 16 sound tight knots not exceeding 3/8" in diameter and is allowed to contain unlimited mineral streaks. A 1 back will not contain any repaired knots.
- 2 Back - It can contain up to 16 sound tight knots not exceeding 3/4" in diameter and can also contain repaired knots, rough cut veneer, and unlimited mineral streak. There is no open defects.
- 4 Back - This is generally referred to as a reject back and is to be used in concealed areas where appearance is of no concern. Most commonly used on 1/4" plywood.
