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 © 2009 By the Hardwood Plywood and Veneer Association
|
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 Knots
Average Number
Max. Size: Dark Part
Max. Size: Total
|
1 per 8 sq ft
4 per 4 x 8' panel
1/8"
1/4"
|
1 per 4 sq ft
8 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
|
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
|
|
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 Knots
Average Number
Max. Size: Dark Part
Max. Size: Total
|
No
|
1 per 8 sq ft
4 per 4 x 8' panel
1/8"
1/4"
|
1 per 4 sq ft
8 per 4 x 8' panel
1/8"
1/4"
|
Scattered Sound and Repaired Knots
Comb. Average Number
Max. Size - Sound
Max. Size - Repaired
Avg. Number - Repaired
|
No
|
No
|
1 per 8 sq ft
4 per 4 x 8' panel
3/8"
1/8"
1 per 8 sq ft
|
|
Mineral Streaks
|
No
|
Slight
|
Occasional
|
|
Bark Pockets
|
No
|
No
|
Few to 1/8" x 1"
|
|
Worm Tracks
|
No
|
No
|
Slight
|
|
Vine Marks
|
Slight
|
Slight
|
Yes
|
|
Cross Bars
|
Occasional
|
Occasional
|
Yes
|
|
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 Knots
Average Number
Max. Size: Dark Part
Max. Size: Total
|
1 per 3 sq ft
10 per 4 x 8' panel
1/8"
1/4"
|
1 per 2 sq ft
16 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, 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
|
|
Small Conspicuous Burls & Pin Knots - Comb. Avg. Number
|
64 per 4 x 8' panel
|
No Limit
|
As agreed
upon between
buyer and seller
|
|
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
|
|
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 1 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
|
|
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
|
|
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"
|
|
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 Plies Adjacent to Faces*
|
K
|
K under AA, A or B
L under C, D or E
|
|
Grade of Other Inner Plies
|
M or better
|
M or better
|
NOTE: If the buyer requires a specific inner ply grade among those as listed in
Table 7, it must be specified.