ANSI/HPVA HP-1-2009 Standards

Reproduced with permission from Hardwood Plywood and Veneer Association (HPVA)

ANSI/HPVA HP-1-2009 Standards©

The Hardwood Plywood and Veneer Association (HPVA) is an ANSI-accredited standards developer that works through its participating membership and other interested outside parties to develop a voluntary standard for hardwood and decorative plywood under due process guidelines set forth by the American National Standards Institute (ANSI). The resulting national consensus standard bears the name, “American National Standard for Hardwood and Decorative Plywood, ANSI/HPVA HP-1- Current Year,” often shortened to ANSI/HPVA HP-1. Any other reference is not appropriate. It is often erroneously called the ANSI Standard, but there are hundreds of ANSI standards, only one of which covers our industry. ANSI does not write the standard or bear any responsibility for its content. The sole involvement by ANSI is to provide a protocol for the development of a standard that includes participation and sign-off by all interested parties in the process, and a format to use so that the resulting standard conforms to due process requirements to qualify for the ANSI designation.

The history of the standard is rich, beginning in 1931 as Commercial Standard CS 35-31, evolving through the National Bureau of Standards as PS 51-71, to its final version today. As mentioned above, it is a voluntary consensus standard, meaning compliance is voluntary, and the contents are a result of a consensus of those involved in its development. While this may seem to be a simple process, today’s version of the standard is the result of an arduous and tumultuous process. It is intended to provide a baseline by which a panel or lot of panels may be judged to ensure what is delivered is what is specified. Once a panel provider agrees to or professes to conform to the standard, it becomes mandatory.

It is important to understand that because of the natural differences in how the look of wood will vary from piece to piece, even from the same tree, every grade will include a range of appearance from the low end of the grade to the high end. The tables in the ANSI/HPVA HP-1 standard and abbreviated here for simplification purposes establish a minimum appearance for each grade. In other words, the tables essentially say that if a given attribute such as a small burl is present, it can’t exceed the size and quantity restrictions listed in the table. What the tables do not say and should not be interpreted to say is that for any grade, every face in that particular grade must have every attribute listed in the amount and size listed in the applicable table. The truth is that not every panel will have every characteristic. Some will have virtually none, but others will have a combination of them, often making the final determination of the grade status of a given piece of veneer quite perplexing. Sometimes a panel face with a faint characteristic that objectively is outside the permitted size for a given grade will look much more desirable than another that has several characteristics that are within the permitted limit, but which are actually quite ugly, yet objectively meet the grade. The resulting inclination is to select the better looking face and reject the ugly one. In fact, quoting from the current industry standard, ANSI/ HPVA HP-1-2009, Section 3.3.1, “NOTE: Because of the inherent individuality of trees, consideration should be given to the overall appearance of the veneer face to determine the appropriate grade for that veneer.”

Regardless of the fact that every effort has been invested to ensure that the standard is as objective as possible, there will always be some level of subjectivity involved when making the final decision as to the grade of a given sheet of veneer. For this reason, there is almost always some degree of overlap in appearance between the bottom end of one grade and the top end of the next grade down, as illustrated in Diagram 1 below.

As can be seen in this diagram, as we go from one grade to the next, not only does the variation in appearance get wider for each, but the amount of overlap between the low end of one grade and the high end of the next grade down gets wider as well.

While the standard consists of numerous sections and complete tables for every grade of face and back by species category, it also includes sections and tables relating to core requirements, glue performance, formaldehyde emissions, dimensions and tolerances, and testing methodology. The following tables are offered as a condensed version of the grade tables in the ANSI/HPVA HP-1 standard for a few select species categories showing a small number of limiting criteria for illustration purposes only. Please check the current ANSI/HPVA HP-1 standard for the full tables and narrative for more complete information.

Note: Some exotic species such as Amaranth/Purpleheart (Peltogyne paniculata) or Zebrano (Microberlinia brazzavillensis), or unusual matchings such as diamond or sunburst do not fit into the grading tables described here or in the industry standard. These and even certain domestic woods such as birds’ eye maple (Acer saccharum) or wormy chestnut (Castanea dentata) must be carefully specified to include expected appearance. They will not be applicable to any particular grade, and therefore should be considered as agreed upon between buyer and seller for appearance purposes. Even so, other requirements of ANSI/HPVA HP-1, including dimensional tolerances, glue performance, and formaldehyde emissions, among others, shall apply.

Diagram 1

ANSI/HPVA HP-1-2009 Standards

ANSI/HPVA HP-1-2009 © 2009 By the Hardwood Plywood and Veneer Association

ASH, BIRCH, MAPLE AND POPLAR: ROTARY-CUT, QUARTER CUT, PLAIN SLICED (From Table 3.1©)
Natural Characteristics A Grade B Grade C Grade
Small Conspicuous Burls & Pin Knots – Comb. Avg. Number 10 per 4 x 8′ panel 16 per 4 x 8′ panel No limit
Conspicuous Burls – Max. Size 3/8″ 1/2″ No limit
Conspicuous Pin KnotsAverage NumberMax. Size: Dark PartMax. Size: Total 1 per 8 sq ft4 per 4 x 8′ panel1/8″1/4″ 1 per 4 sq ft8 per 4 x 8′ panel1/8″1/4″ No limit
Scattered Sound and Repaired KnotsComb. Average NumberMax. Size – SoundMax. Size – Repaired

Avg. Number – Repaired

No 1 per 8 sq ft4 per 4 x 8′ panel3/8″1/8″

1 per 8 sq ft

1 per 4 sq ft8 per 4 x 8′ panel1/2″1/2″

1 per 8 sq ft

Mineral Streaks Slight Slight Yes
Bark Pockets No Few to 1/8″ x 1″ Few to 1/4″ x 2″
Worm Tracks Slight Slight; Ash Yes Yes
Vine Marks Slight Slight Yes
Cross Bars Slight Yes Yes
MAHOGANY, ANIGRE AND SAPELE: ROTARY-CUT, QUARTER CUT, PLAIN SLICED (From Table 3.2©)
Natural Characteristics AA Grade A Grade B Grade
Small Conspicuous Burls & Pin Knots – Comb. Avg. Number 6 per 4 x 8′ panel 10 per 4 x 8′ panel 16 per 4 x 8′ panel
Conspicuous Burls – Max. Size 1/4: 3/8″ 1/2″
Conspicuous Pin KnotsAverage NumberMax. Size: Dark Part

Max. Size: Total

No 1 per 8 sq ft4 per 4 x 8′ panel1/8″

1/4″

1 per 4 sq ft8 per 4 x 8′ panel1/8″

1/4″

Scattered Sound and Repaired KnotsComb. Average NumberMax. Size – Sound

Max. Size – Repaired

Avg. Number – Repaired

No No 1 per 8 sq ft4 per 4 x 8′ panel3/8″

1/8″

1 per 8 sq ft

Mineral Streaks No Slight Occasional
Bark Pockets No No Few to 1/8″
Worm Tracks No No Slight
Vine Marks Slight Slight Yes
Cross Bars Occasional Occasional Yes
RED AND WHITE OAK: ROTARY-CUT, QUARTER CUT, PLAIN SLICED (From Table 3.3©)
Natural Characteristics A Grade B Grade  
Small Conspicuous Burls & Pin Knots – Comb. Avg. Number 12 per 4 x 8′ panel 24 per 4 x 8′ panel No limit
Conspicuous Burls – Max. Size 3/8″ 1/2″ No limit
Conspicuous Pin KnotsAverage Number

Max. Size: Dark Part

Max. Size: Total

1 per 3 sq ft10 per 4 x 8′ panel

1/8″

1/4″

1 per 2 sq ft16 per 4 x8′ panel

1/8″

1/4″

No limit
Scattered Sound and Repaired KnotsComb. Average Number

Max. Size – Sound

Max. Size – Repaired

Avg. Number – Repaired

No 1 per 8 sq ft4 per 4 x 8′ panel

3/8″

1/8″

1 per 8 sq ft

1 per 4 sq ft8 per 4 x 8′ panel

1/2″

1/2″

1 per 8 sq ft

Mineral Streaks Slight, Blending Few to 12″ Yes
Bark Pockets No Few to 1/8″ x 1″ Few to 1/4″ x 2″
Worm Tracks No Slight Few
Vine Marks Slight Yes Yes
Cross Bars Slight Yes Yes
HICKORY: ROTARY-CUT, QUARTER CUT, PLAIN SLICED (From Table 3.4©)
Natural Characteristics A Grade B Grade As agreed upon between buyer and seller 

 

 

 

 

 

Small Conspicuous Burls & Pin Knots – Comb. Avg. Number 64 per 4 x 8′ panel No Limit
Conspicuous Burls – Max. Size 3/8″ 1/2″
Conspicuous Pin Knots

Average Number

Max. Size: Dark Part

Max. Size: Total

2 per 1 sq ft

64 per 4 x 8′ panel

1/8″

1/4″

No Limit

1/8″

1/4″

Scattered Sound and Repaired Knots

Comb. Average Number

Max. Size – Sound

Max. Size – Repaired

Avg. Number – Repaired

No 1 per 8 sq ft

4 per 4 x 8′ panel

3/8″

1/8″

1 per 8 sq ft

Mineral Streaks Slight Yes
Bark Pockets Small, Occasional Few to 1/4″ x 2″
Worm Tracks Slight Few
Vine Marks Occasional Yes
Cross Bars Occasional Yes
Bird Peck Slight Yes
Knife Marks Knife marks may occur in these high density species
WALNUT AND CHERRY: PLAIN SLICED, QUARTER CUT, ROTARY CUT (From Table 3.5©)
Natural Characteristics A Grade B Grade C Grade
Small Conspicuous Burls & Pin Knots – Comb. Avg. Number 24 per 4 x 8′ panel 64 per 4 x 8′ panel No Limit
Conspicuous Burls – Max. Size 3/8″ 1/2″ No Limit
Conspicuous Pin Knots

Average Number

Max. Size: Dark Part

Max. Size: Total

1 per 2 sq ft

16 per 4 x 8′ panel

1/8″

1/4″

1 per 2 sq ft

32 per 4 x 8′ panel

1/8″

1/4″

No Limit
Scattered Sound and Repaired Knots

Comb. Average Number

Max. Size – Sound

Max. Size – Repaired

Avg. Number – Repaired

No 1 per 8 sq ft

4 per 4 x 8′ panel

3/8″

1/8″

1 per 8 sq ft

1 per 4 sq ft

8 per 4 x 8′ panel

1/2″

1/2″

1 per 8 sq ft

Mineral Streaks Slight Yes Yes
Bark Pockets No Few to 1/8″ x 1″ Few to 1/4″ x 2″
Worm Tracks No Slight Few
Vine Marks Occasional Yes Yes
Cross Bars Occasional Yes Yes
Gum Spots Occasional gum spots in Cherry Gum spots and gum streaks in Cherry
BACK GRADES (From Table 6©)
Grade Description 1 Back 2 Back 3 Back 4 Back
Sapwood Yes Yes Yes Yes
Discoloration & Stain Yes Yes Yes Yes
Mineral Streaks Yes Yes Yes Yes
Sound Tight Burls Yes Yes Yes Yes
Sound Tight Knots Max. diameter 3/8″ Max. diameter 3/4″ Max. diameter 1 1/2″ Yes
Max. Number of Tight Knots 16 16 Unlimited to 1/2″;

No more than 16 from 1/2″ to 1 1/2″

Unlimited
Knotholes No 1/2″ repaired 1″ 4″
Max. Combined Number of Knotholes and Repaired Knots None All repaired;

Unlimited to 3/8″;

No more than 8 from 3/8″ to 1/2″

Unlimited to 3/8″;

No more than 10 from 3/8″ to 1″

Unlimited
Wormholes Filled Filled Yes Yes
Splits or Open Joints Six 1/8″ x 12″ repaired Six 3/16″ x 12″ repaired Yes, 3/8″ x 1/4″

Length of Panel (LOP)

1″ to 1/4 LOP

1/2″ to 1/2 LOP

1/4″ to Full LOP

Doze & Decay Firm areas of doze Firm areas of doze Firm areas of doze Areas of doze and decay provided serviceability of panel is not impaired
Rough Cut/Ruptured Grain Two 8″ diameter areas 5% of panel Yes Yes
Bark Pockets 1/8″ wide repaired 1/4″ wide repaired Yes Yes
Laps No Repaired Yes Yes
CORE GRADES (From Table 7©)
Grade Description J Grade K Grade L Grade M Grade
Thickness of Crossband Adjacent to Faces Any Thickness Thicker than 1/10″ 1/10″ and thinner Any thickness Any thickness
Knotholes and Other Round Elliptical Openings (Max. Diameter) None 3/8″ 3/4″ 1″ 2 1/2″
Splits, Gaps, and Other Elongated End or Edge Openings – Visible on only one end or edge of panel (Max. Width) 1/8″ 1/4″ 1/2″ 1″
LIMITING CRITERIA FOR PLYWOOD (From Table 8©)
Limiting Factors TYPE 1 (EXTERIOR) TYPE 2 (INTERIOR)
Bond Line Requirements Fully waterproof Water resistant
Bond Line (glue bond) Test Performance Dry and cyclic-boil shear Three-cycle soak and dry
Grade and Limitations of Inner Piles Adjacent to Faces* K K under AA, A or B

L under C, D or E

Grade of Other Inner Piles M or better M or better