American Softwood 
Lumber StandardVoluntary Product Standard PS 20-15
April 2015
Supersedes Voluntary Product Standard PS 20-10 
 
 
Voluntary Product Standard PS 20 -15 
   
 
 
 
American Sof twood Lumber Standard  
 
 
 
 
 
Supersedes Voluntary Product Standard PS 20 -10 
 
 
 
 
 
April  2015 
 
 
 
 
  
 
 
  
 
 
  
 
U.S. Department of Commerce  
Penny Pritzker, Secretary  
 
National Institute of Standards and T echnology  
Willie E. May , Acting Under Secretary of Commerce for Standards and  Technology and Director  
 
 
 
 
   
  
 
 
 
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 2  
 
VOLUNTARY PRODUCT STANDARDS  
 
 
 
 
Development of Voluntary Product 
Standards  
 
Voluntary P roduct Standards are developed 
under pro cedures published by the Department 
of Commerce in Title 15 Code of Federal Reg u-
lations  Part 10, Procedures for the Development 
of Voluntary Product Standards . The purpose of 
these standards is to establish nationall y rec-
ognized requirements for products and provide 
all concerned interests with a basis for common 
understanding of the characteristics of the 
products. The National Institute of Standards 
and Technology (NIST) administer s the Volu n-
tary Product Standards P rogram on a reim-
bursable basis.  
 
Role of NIST  
 
The role of NIST in the establishment of Volu n-
tary Product Standards is to act as an unbiased coordinator in their development, provide edit o-
rial assistance in their preparation, supply such assistance and rev iew as is required to assure 
their technical soundness, and to seek satisfa c-
tory resolution of valid points of disagreement. 
NIST also determines compliance with the cr i-
teria of the Department’s procedures, provides secretarial functions for each committee  ap-
pointed under the procedures, and publishes 
the standards as public documents.  
 
Producers, distributors, users, consumers, and other interested groups contribute to the esta b-
lishment of Voluntary Product Standards by i n-
itiating and participating in thei r develo pment, providing technical or other counsel as appr o-
priate, promoting the use of and support for the 
standards, and assisting in keeping the stand-
ards current with respect to advancing techno l-
ogy and marketing practices.  
 Use of Voluntary Product S tandards  
 The use of Voluntary Product Standards is vo l-
untary. NIST has no regulatory power in the 
enforcement of their provisions: however, since 
the standards represent a consensus of all i n-
terested groups, their provisions are likely to become establish ed as trade customs. In add i-
tion, when a Voluntary Product Standard is 
made a part of a legal document, such as a sales 
contract or code, compliance with the standard 
is enforc eable.  
 
The benefits derived from Voluntary Product 
Standards are in direct proportion to their ge n-
eral recognition and actual use. Producers and 
distributors whose products meet the requir e-
ments of a Voluntary Product Standard may re-
fer to the standard in advertising and on labels 
to promote greater public understanding for confidenc e in their products. At times, purcha s-
ers may order products conforming to the re-quirements of a Voluntary Product Standard.  
 For copies of the Voluntary Product Standards proce dures or for more information concerning 
the development and use of these stand ards, 
contact the Standards Services  Division , Na-
tional Institute of Standards and Technology, Gaithersburg, MD 20899- 2100. 
 
 
   
 
 
 
3  
  
 
 
 
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 4  
 
 
  
  Voluntary Product Standard 
 PS 20 -15 
 (Supersedes Voluntary Product Standard PS 20 -10) 
 
 
 
  
AMERICAN SOFTWOOD LUMBER STANDARD  
  
PREFACE  
   The American Softwood Lumber Standard was d eveloped by the American Lumber  
Standard Committee (ALSC) in accordance with the Pr ocedures for the Development of Voluntary 
Product Sta ndards  of th e U.S. Department of Commerce. The ALSC membership is appointed by 
the Secretary of Commerce to constitute a proper balance among producers, distributors, and consumers of softwood lumber. Pursuant to a U.S. District Court order, the ALSC and its Board of Review (Board) operate as independent bodies with defined functions with regard to establis h-
ing, maintaining, implementing and enforcing this Standard. Through a consensus process, the ALSC maintains the Standard and establishes policies and adopts other s tandards by which the 
Board certifies grading rules, approves design values, accredits agencies to grade and inspect u n-
der those rules and monitors the agencies' performance. The purpose of this standardization pro-gram for manufacturers, distributors, user s and consumers is to provide for the correct grade 
mark labeling of lumber by mills using the service of an accredited agency. This Standard pro-vides for the grading of structural lumber by both visual and mechanical means.   A separate con-
sensus body, the  National Grading Rule Committee (NGRC) is established to develop and main-
tain nomenclature and d escriptions of grades for dimension lumber that conform to this Stand-
ard. 
 This Standard is applies to  domestic production consumed in and exported from the Un ited 
States, and for lumber imported into the United States.  
 5 ABSTRACT  
 
This Standard pertains to softwood lumber. It 
establishes standard sizes and requirements for 
development and coordination of the lumber 
grades of the various sp ecies, the assignment  of 
design values when called for, and the prepar a-
tion of grading rules applicable to each species. 
It provides for implementation of the Standard 
through an accreditation and certification pr o-
gram to a ssure uniform industry -wide marking 
and inspection.  
 
It establishes principal trade classifications and 
lumber sizes for yard, structural, factory and shop use and provides for the classification, measurement, grade marking of rough and 
dressed sizes of lumber items. Terms and pr o-
cedures are defined to provid e a basis for the 
use of uniform methods in the grading, inspe c-
tion, measur ement and description of softwood 
lumber. It includes the organization and func-tions of the American Lumber Standard Co m-
mittee, the Board of Review, and the Na tional 
Grading Rule Co mmittee. Commercial names of 
the principal softwood species, definitions of 
terms used in describing standard grades of 
lumber and commonly used industry abbrevi a-
tions are also provided.  
 
The Standard was developed by the American Lumber Standard Committee  in accordance 
with procedures of the U. S. Department of 
Commerce.  
 
KEY WORDS  
 
Accreditation ; ALSC Board of Review; certific a-
tion of grading rule; DOC PS 20 -15; lumber i n-
spection; lumber sizes; mois ture content of 
lumber; National Grading Rule; softwood lu m-
ber standard   
 
 
  
 
 
 
  
  
 
   
 
 
   
 
 
   
 
 
  
 
  
 
 
 
  
 
 
 
 
 6 TABLE OF CONTENTS  
 
PREFACE  .................................................................................................................................  5 
1.  SCOPE  .................................................................................................................................  9 
2.  TERMINOLOGY  ................................................................................................................ 10 
3.  CLASSIFICATION  ............................................................................................................ 11 
4.  MEASUREMENT AND TALLY  ........................................................................................ 12 
5.  LUMBER SIZES  ................................................................................................................ 13 
6.  GRADING RULE REQUIREMENTS  ............................................................................... 18 
7.  GRADE MARKING (GRADE STAMPING)  ...................................................................... 21 
8.  INSPECTION AND REINSPECTION  .............................................................................. 22 
9.  AMERICAN LUMBER STANDARD COMMITTEE ......................................................... 24 
10.  BOARD OF REVIEW  ....................................................................................................... 26 
11.  NATIONAL GRADING RULE COMMITTEE ................................................................ 28 
12.  REFERENCES  ................................................................................................................. 29 
APPENDIX A  COMMERCIAL NAMES OF THE PRINCIPAL SOFTWOOD SPECIES  .... 31 
APPENDIX B  DEFINITIONS OF TERMS USED IN DESCRIBING  
STANDARD GRADES OF LUMBER ............................................................... 34 
APPENDIX C   LUMBER INDUSTRY ABBREVIATIONS  .................................................. 44 
APPENDIX D  IMPLEMENTATION AND MAINTENANCE OF STANDARD  .................. 47 
 
 7  
  
 
 
    
 
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 8 AMERICAN SOFTWOOD LUMBER STANDARD  
 
 
 
Effective April , 2015  
 
 
 
[This Standard which was initiated by the American Lumber Standard Committee, has been developed under the Procedures for the Development of Voluntary Product Standards  of the U.S. Department of 
Commerce to supersede PS 20-10 “American Softwood Lumber Sta ndard.”]  
 
 
 
1.  SCOPE 
 
1.1 General  
 
1.1.1 This Voluntary Product Standard estab-
lishes and maintains, through a consensus pr o-
cess and in the public interest, standard sizes 
(both in metric
1 and conventional units) and ge n-
eral requirements for developing grades of sof t-
wood lumber . It is implemented through an i n-
ternationally recognized accreditation and certi-
fication program, the purpose of which is to pro-
vide for uniform, industry -wide grade marking 
and inspe ction of soft wood lumber.  
 
1.1.2 This Standard also provides a basis for 
the coordination of the grades of the various sp e-
cies of softwood lumber, the assignment of design 
values to lumber when called for, and the prep a-
ration of grading rules applic able to each species . 
The provisions of this Standard apply to stru c-
tural lumber manufactured from hardwood sp e-
cies or lumber manufactured from foreign species 
when the species is included in rules certified by 
the Board of Review. It is not intended to be used either as grad ing rules or as purchase specifica-
tions. Italicized notes in this Standard are non-mandatory.  
1 Metric units are provided initially followed by conventio n-
al units.   1.1.3 It establishes the principal trade class i-
fications and sizes of softwood lumber for yard, 
structural, factory and shop use. It provides for 
the classificati on, measurement, grading and 
grade marking of rough and dressed sizes of va r-
ious items of lumber including finish, boards, dimension and timbers. Terms and procedures 
are defined and discussed to provide a basis for 
the use of uniform methods in the gradin g, in-
spection, measurement and description of sof t-
wood lumber.  
 
Note:  The provisions of this Standard do not a p-
ply to the myriad of products of remanufacture 
(for example: turned balusters, peeler cores, etc.) or manufactured components (for example: trus s-
es, lattice panels, I -joists, etc.) that use  “American 
Lumber Standard”  (ALS ) program lumber as a 
raw material.  
 1.1.4  This Standard applies to lumber that is 
to be iden tified as a manufactured product from 
a softwood log in a  sawmill, or in a sawmill and  
planing mill. Such lumber, when rough, shall show saw or other primary manufac turing marks 
in the wood on the four longitudinal surfaces of each piece for its over -all length and shall not 
have been further manufactured other than by crosscutting, ripping , resawing, joining by fi n-
gerjointing, face -gluing  and/or edge -gluing , sur-
 9                                                            facing with or without end matching, and wor k-
ing. 
 
1.1.5 In this Standard, lumber conforming to 
the basic minimum size and grade provisions 
herein is designated “American Lumber Stan d-
ard” (ALS) program lumber only when graded 
under rules certified by the Board of Review 
(Board).  
 
1.2 This Standard also includes the fo l-
lowing:  
(a) Organization and functions of the Amer i-
can Lumber Standard Committee (ALSC), the Board, and the National G rading Rule 
Committee (NGRC) 
2; 
(b) Commercial names of the principal sof t-
wood species (Appendix A);  
(c) Definitions of terms used in describing standard grades of lumber (Appendix B);  
(d) Commonly used lumber industry abbrev i-
ations (Appendix C); and  
(e) Infor mation on implementation, and hi s-
tory of the Standard (Appendix D).  
 2.  TERMINOLOGY  
 
2.1 Accreditation --Procedure by which an 
authorit ative body gives formal recognition that a 
body or person is competent to carry out specific 
tasks. 
 
2.2 Board measure --The term used to ind i-
cate that a board foot is the unit of measurement of lumber. The number of board feet in a piece of lumber is obtained by multiplying the nominal 
thickness in inches  or fraction of an inch by the 
nominal width in feet by the length in f eet.  For 
metric measure ment, [see 2.5]  
 
2 The American Lumber Standard Committee, Inc., its 
Board of Review, and its National Grading Rule Co m-
mittee disclaim any liability for damages, including 
consequential damages, in connection with the use or performance in use of products pr oduced.  2.3 Certification --Procedure by which a 
third party gives written assurance that a pro d-
uct, process or service conforms to specified re-
quirements.  
 
2.4 Characteristics --Distinguishing fe a-
tures which by their extent, loc ation, and number 
determine the quality of a piece of lumber. The 
limiting characteristics of any grade of lumber d e-
scribed in certified grading rules shall be ex-
pressed within the terms of the definitions in A p-
pendix B.  
 
2.5 Cubic measurement --The term used t o 
indicate that a cubic meter is the metric unit of 
measurement of lumber. The number of cubic m e-
ters in a piece of lumber is obtained by multiply-ing the dressed thickness in millimeters by the 
dressed width in millimeters by the length in m e-
ters, and divi ding the product by 1,000,000. [see 
Appendix B1]  
 
2.6 Design values--
 Published design data 
that are representative of the strength and stif f-
ness of specific grades and species/species groups of lumber .   
 2.7 Dry lumber --Lumber of less than nom i-
nal 5- inch thi ckness which has been seasoned or 
dried to a maximum moisture content of 19 pe r-
cent.  
 
Note: Lumber of nominal 5 -inch or greater thick-
ness (timbers) is often manufactured and sold 
without drying.  
 
When the maximum moisture content is specified 
for lumber of  nominal 5 -inch or greater thick-
ness, it shall be in accordance with the provisions 
of the applicable lumber grading rules certified by the Board, which for some species defines dry lumber as having a maximum moisture content 
higher than 19 percent.[see 6. 2.6]  
 
2.8 Grade marked (grade stamped) --
Lumber that displays the official grading mark of 
 10                                                            an agency that is made by rubber stamps, ink jet 
sprayers, tags and/or other methods when found 
acceptable by that agency. A grade mark is owned 
by the grading agenc y and is applied to lumber 
that conforms to the requirements of a designated 
grading rule. Except for marks used in co nnection 
with Certificates of Inspection or Reinspection, all 
grade marks shall indicate the following: 1) the 
mill number, name, or abbre viation; 2) the agency 
symbol; 3) the species or combination of species of 
the lumber; 4) whether the lumber was dry or green when manufactured ; and 5) the ap propriate 
grade. Where required by the grading rules, grade 
marks shall also denote rule paragraphs under 
which the lumber was graded or other similar in-form ation. 
 2.9 Grading agency--An organization ac-
credited by the Board that engages in the grading of lumber or that licenses and supervises facilities that employ graders to grade and/or to place gra de 
marks upon lumber pro ducts.  
 
2.10 Grading rules--Requirements and spe c-
ifications for the manufacture, inspection and 
grading of desig nated species of lumber. Lumber 
manufactured and graded according to the prov i-
sions of this Standard and the grading rul es for 
the species in question shall be regarded as ALS program lumber.  
 2.11 Green lumber --Lumber of less than 
nominal 5- inch thickness which has a moisture 
content in excess of 19 percent. For lumber of nominal 5- inch or greater thickness (timbers), 
green shall be defined in accordance with the pr o-
visions of the applicable lumber grading rules ce r-
tified by the Board.  
 2.12 Heat treated (HT) --lumber or other 
wood products that have been heat ed in a closed 
chamber, with or without moisture content redu c-
tion, until it achieves a minimum core temper a-
ture of 56
  °C for a min imum of 30 minutes.  
 2.13 Kiln dried (KD) --Lumber that has been 
seasoned in a chamber to a predetermined moi s-
ture content by appl ying heat.  
 
2.14 Lumber --Lumber is defined as a manu-
factured product derived from a log  through sa w-
ing or planing .  [see 3.3]  
 
2.15 Lumber grades --Manufacturing cat e-
gories of lumber that provide the extent and lim i-
tations of the characteristics permitted in the pa r-
ticular grade.  
 2.16 Nominal size --The label  designa tion for 
lumber size categor ies that does not reflect the 
dressed size. The nominal size is greater than the 
dressed size i.e ., a dry “2 by 4” is surfaced to 38 
mm by 89 mm (1 1/2 by 3 1/2 inches).  
 
2.17 Species --The commercial names co n-
tained in Appendix  A for lumber cut from the 
principal botanical species of softwood shall be 
used in the formulation of lu mber grading rules 
and in the terms of purchase and sale of ALS 
program lumber.  
 
2.18 Worked lumber (working) --Dressed 
lumber that has also been matche d, shiplapped or 
patterned.  
 3.  CLASSIFICATION  
 
3.1 General —ALS program lumber shall be 
classified according to the use, extent -of-
manufacture and nominal size.  
 
3.2 Use 
 
3.2.1  Yard lumber --Lumber of those grades, 
sizes, and patterns intended for ordinary  con-
struction and building purposes. [see 6.3.1]  
 
3.2.2  Structural lumber --Lumber for use 
where d esign values are required. [see 6.3.2]  
 
 11 3.2.3  Factory and shop lumber --Lumber 
that is produced or selected for remanufacturing 
purposes and intended for non -structural applic a-
tions. [see 6.3.3]. 
 3.3 Extent- of-manufacture  
 
3.3.1  Rough lumber --Lumber which has not 
been dressed (surfaced) but which has been 
sawed, edged and trimmed at least to the extent of showing saw or other primary manufacturing marks in the w ood on the four longitudinal su r-
faces of each piece for its over -all length. Lumber 
surfaced on one edge (S1E), two edges (S2E), one side (S1S), or two sides (S2S) is classified as rough lumber in the unsurfaced width or thickness.  
 3.3.1.1  Saw -sized lumbe r – Lumber uniformly 
sawn to the dressed size for surfaced lumber, and not planed on the faces, for uses requiring a rough texture. When saw sized lumber is grade marked it shall be labeled as such.  
 
3.3.1.2  Sized lumber – Lumber uniformly 
manufactured to dressed surfaced sizes. Sized 
lumber may be rough, surfaced or partially su r-
faced on one or more faces. When sized lumber is grade marked it shall be la beled as such.  
 3.3.2  Dressed (surfaced) lumber --Lumber 
that has been surfaced by a machine (to attain smoothness of surface and uniformity of size) on 
one side (S1S), two sides (S2S), one edge (S1E), 
two edges (S2E), or a combination of sides and 
edges (S1S1E, S1S2E, S2S1E, S4S). Lumber sur-faced S1E, S2E, S1S, S2S, S1S1E, S1S2E, S2S1E, S4S is classified as dressed (surfaced) lumber in 
the sur faced width or thickness.  
 
3.3.3  Worked lumber --Dressed lumber that 
has also been matched, shiplapped or patterned.  
 
3.3.3.1  Matched (tongue -and-grooved, ce n-
termatch) lumber --Lumber worked with a 
tongue on one edge of ea ch piece and a groove on 
the opposite edge to provide a close tongue- and-groove joint by fitting two pieces together; when 
end-matched, the tongue and groove are worked 
in the ends also.  
 3.3.3.2  Shiplapped lumber --Lumber worked 
or ra bbeted on both edges of each piece to provide 
a close- lapped joint by fitting two pieces together.  
 
3.3.3.3  Patterned lumber --Lumber shaped to 
a pat tern or to a molded form, in addition to being 
dressed, matched, or shiplapped, or any combin a-
tion of these workings.  
 3.4 Nominal  size  
 
3.4.1  Boards --Lumber of less than nominal 2-
inch thickness and of nominal 2- inch or greater 
width. Lumber of less than nominal 2- inch thic k-
ness and of less than nominal 6- inch width is de s-
ignated as strips or boards.  
 3.4.2  Dimension-- Lumber from n ominal 2 -
inch to, but not including, nominal 5- inch thic k-
ness, and of nominal 2 -inch or greater width.  D i-
mension is also designated as framing, joists, 
planks, rafters, or studs.  
 
3.4.3  Timbers --Lumber of nominal 5- inch or 
greater in least dimension. Timb ers are also de s-
ignated as beams, stringers, posts, caps, sills, 
girders, or purlins.  
 
3.4.4  The dressed sizes of all lumber dimen-
sions referenced in this Standard in terms of 
"nominal" sizes are set -out in Tables 1 through 4. 
The use of "nominal" sizes in  the language of this 
Standard follows the practice of the industry. No inferences shall be drawn that the "nominal" sizes 
are dressed sizes.  [see 2.16]  
 4.  MEASUREMENT AND TALLY  
 
4.1 Tally, standard sizes --Lumber shall be 
tallied board measure or cubic measu re. Dressed 
sizes shall be used when lumber is measured by 
cubic measure.  
 12  
Note: The invoices for dressed  lumber of standard 
sizes should show the number of pieces of each 
nominal size and length as well as the actual 
thickness and width of such lumber.   
 4.2 Tally, nonstandard sizes --Lumber fi n-
ished to nonstandard sizes shall be tallied board 
measure as of e ither the rough or the nominal size 
that was used in its manufacture. Cubic measure 
of lumber shall also be permitted. Dressed sizes shall be used when lumber is mea sured by cubic 
measure.  
 Note: The dressed thickness and width of such lumber should be shown on the invoice.  
 4.3 Board rule tally - In lumber specified to 
be mea sured with a board rule on dressed widths, 
pieces measuring to the even half foot are alte r-
nately counted as of the next higher and lower foot count; fractions below the half foot are dropped, and fractions above the half foot are 
counted as of the next higher foot.  
 
4.4 Averages
3--length, width --The average 
length in feet of a shipment of lumber is computed 
by dividing the total length in feet by the total 
number of pieces in the shipment. The average 
width in inches of a shipment of lumber of nom i-
nal 1 inch or less thickness is computed by divid-
ing the total board feet by the total length in feet 
and multiplying the results by 12; but if the pieces 
are thicker than nominal 1 inch, the total board 
foot tally is divided first by the nominal thickness as expressed in inches and fractions of an inch.  
 5.  LUMBER SIZES  
 5.1 Rough size --The  minimum rough thic k-
ness of dry or unseasoned lumber 1 or more inches 
in nominal thickness shall be not less than 3.2 
mm (1/8 inch) thicker than the corresponding 
minimum dressed thickness, except that up to 20 
3 This computation applies to conventional units.  percent of a shipment shall be not less than 2.4 
mm (3/32 inch) thicker than the corresponding 
minimum dressed thickness. The minimum rough 
widths shall not be less than 3.2 mm (1/8 inch) 
wider than the corresponding minimum dressed width.  
 
5.2 Dressed sizes--Dressed sizes of lumber 
shall equal or ex ceed the minimum sizes shown in 
Tables 1, 2, 3 and 4. Sizes in Tables 1, 2, 3 and 4 
pertain to those items as measured at time of manufacture. Lumber will change in dimension 
(shrink or expand) in response to its equilib rium 
moisture content. [see 6.2.3.1 and 6.2.5.1] [see al-
so 5.3.1 covering length and 7.3 for grade mar king 
nonstandard sizes.]  
 5.3 Lengths  
 5.3.1  Standard --Standard lengths of lumber 
shall be in multiples of 0.3048 m (1 foot) or 0.6096 m (2 feet) as specified in the certified grading rules.  
 
 5.3.2  Trimmed --Unless otherwise stated in 
the contract of purchase, lumber shall be trimmed for the removal of spur and splintered ends, and if 2 inches or less in nom inal thickness (except lath), 
shall be double -end-trimmed to a length that is 
not less  than the nominal length and that is not 
more than 76 mm (3 inches) in excess of nominal length. The overlength tolerance in nominal 2  
inch dimension over 305 mm (12 inches) wide or 
over 6.1 m (20 feet) in length is 305 mm (12 inch-
es). 
 Note:  The marketin g practice covering lengths of 
lumber should permit the buyer to obtain specified 
lengths or specified assortments of lengths.  
 
 13                                                            Table 1. Nominal and minimum -dressed dry sizes of finish, flooring, ceiling, partition, and 
stepping at 19 percent maximum -mois ture content.  
 
The thicknesses apply to all widths and all widths apply to all thicknesses except as modified. Sizes are 
given in millimeters and inches. Metric units are based on dressed size. See B1, A ppendix B for rounding 
rule for metric units.  
 
Item  Thicknesses  Widths  
Nominal  
Inch  Minimum Dressed  Nominal  
Inch  Minimum Dressed  
mm inch  mm inch  
Finish  3/8 
1/2 5/8 3/4 
1 
1-1/4 
1-1/2 
1-3/4 
2 
2-1/2 
3 
3-1/2 
4 8 
11 14 16 
19 
25 
32 
35 
38 51 64 76 
89 5/16 
7/16 9/16 
5/8 
3/4 
1 
1-1/4 
1-3/8 
1-1/2 
2 
2-1/2 
3 
3-1/2 2 
3 
4 
5 
6 
7 
8 
9 
10 
11 12 14 
16 38 
64 89 
114 
140 
165 
184 
210 
235 260 286 337 
387 1-1/2 
2-1/2 
3-1/2 
4-1/2 
5-1/2 
6-1/2 
7-1/4 
8-1/4 
9-1/4 
10-1/4 
11-1/4 
13-1/4 
15-1/4 
Flooring a 3/8 
1/2 5/8 
1 
1-1/4 
1-1/2 8 
11 14 
19 
25 
32 5/16 
7/16 9/16 
3/4 
1 
1-1/4 2 
3 
4 
5 
6 29 
54 79 
105 130 1-1/8 
2-1/8 
3-1/8 
4-1/8 
5-1/8 
Ceiling a 3/8 
1/2 5/8 
3/4 8 
11 14 
17 5/16 
7/16 9/16 
11/16  3 
4 
5 
6 54 
79 
105 
130 2-1/8 
3-1/8 
4-1/8 
5-1/8 
Partition a 1 18 23/32 3 
4 
5 
6 54 
79 
105 
130 2-1/8 
3-1/8 
4-1/8 
5-1/8 
Stepping  1 
1-1/4 
1-1/2 
2 19 
25 32 
38 3/4 
1 
1-1/4 
1-1/2 8 
10 12 184 
235 286 7-1/4 
9-1/4 
11-1/4 
 
 
a In tongued -and-grooved flooring and in tongued -and-grooved and shi plapped ceiling of 8 mm (5/16 inch), 11 mm (7/16 
inch), and 14 mm (9/16 inch)  dressed thicknesses, the tongue or lap shall be 5 mm (3/16 inch) wide, with the over -all 
widths 5 mm (3/16 inch) wider than the face widths shown in the above table. In all other worked lumber shown in 
this table of dressed thicknesses of 16 mm (5/8 inch) to 32 mm (1 -1/4 inches), the tongue shall be 6 mm (1/4 inch) 
wide or wider in tongued -and-grooved lumber, and the lap shall be 10 mm (3/8 inch) wide or wider in shiplapped 
lumber, and the over- all widths shall be not less than the dressed face widths shown in the above table plus the 
width of the ton gue or lap.  
 14 Table 2. Nominal and minimum -dressed dry sizes of siding at 19 percent maximum -
moisture content.  
 
The thicknesses apply to all widths and all widths apply to all thicknesses. Sizes are given in millimeters 
and inches. Metric units are based on  dressed size. See B1, Appendix B for roun ding rule for metric units.  
 
Item  Thicknesses  Widths  
Nominal  
Inch  Minimum Dressed  Nominal  
Inch  Minimum Dressed  
mm inch  mm inch  
Plain Bevel  1/2 
9/16 
5/8 
3/4 
1 
  11 butt, 5 tip  
12 butt, 5 tip  
14 butt, 5 tip  
17 butt, 5 tip  
19 butt, 5 tip  
 7/16 butt, 3/16 tip  
15/32 butt, 3/16 tip  
9/16 butt, 3/16 tip  
11/16 butt, 3/16 tip  
3/4 butt, 3/16 tip  4 
5 
6 
8 
10 
12 89 
114 
140 
184 
235 
286 3-1/2 
4-1/2 
5-1/2 
7-1/4 
9-1/4 
11-1/4 
Rabbeted 
Bevel  1/2 
3/4 11 butt, 5 tip  
17 butt, 7 t ip 7/16 butt, 3/16 tip  
11/16 butt, 9/32 tip  4 
6 
8 
10 
12 89 
140 
184 
235 
286 3-1/2 
5-1/2 
7-1/4 
9-1/4 
11-1/4 
Bungalow  3/4 17 butt, 5 tip  11/16 butt, 3/16 tip  6 
8 
10 12 140 
184 
235 
286 5-1/2 
7-1/4 
9-1/4 
11-1/4 
Shiplap (10 
mm (3/8 in.) 
lap)b 5/8 
1 14 
18 a  9/16 
23/32 a  4 
5 
6 
8 
10 
12 76 
102 
127 
171 
222 
273 3 
4 
5 
6-3/4 
8-3/4 
10-3/4 
Shiplap   ( 13 
mm (1/2 in.) 
lap)b 5/8 
1 
2 14 
18 a 
38 9/16 
23/32 a  
1-1/2 4 
5 
6 
8 
10 
12 73 
98 
124 
168 
219 
270 2-7/8 
3-7/8 
4-7/8 
6-5/8 
8-5/8 
10-5/8 
Dressed and 
Matched 
(Tongue and 
Grooved, 6 
mm (1/4 in.) 
tongue)b 5/8 
1 14 
18 a   9/16 
23/32 a  4 
5 
6 
8 
10 
12 79 
105 
130 
175 
225 
276 3-1/8 
4-1/8 
5-1/8 
6-7/8 
8-7/8 
10-7/8 
Dressed and 
Matched 
(Tongue and 
Grooved, 10 
mm (3/8 in.) 
tongue)b 1 18 a 23/32 a 4 
6 
8 
10 
12 76 
127 
171 
222 
273 3 
5 
6-3/4 
8-3/4 
10-3/4 
 
a Minimum dressed thickness for 1 -inch nominal redwood and western red cedar shiplap and tongue and groove siding 
patterns is 17 mm (11/16 inch).  
b In siding lumber less than nominal 2 -inch thickness, the tongue shall be 6 mm (1/4 inch) o r 10 mm (3/8 inch) wide in 
tongued and grooved lumber and the lap shall be 10 mm (3/8 inch) or 13 mm (1/2 inch) wide in shiplapped lumber 
with the over -all widths 6 mm (1/4 inch), 10 mm (3/8 inch) and 13 mm (1/2 inch) wider, respectively, than the face 
widths shown in the above table.  
 15 Table 3. Nominal and minimum -dressed sizes of boards, dimension, and timbers.  
 
The thicknesses apply to all widths and all widths apply to all thicknesses. Sizes are given in millimeters and inches. 
Metric units are based on  dressed size. See B1, Appendix B for roun ding rule for metric units.  
 
Item  Thicknesses  Widths  
Nominal  
Inch  Minimum Dressed  Nominal  
Inch  Minimum Dressed  
Dry a Green a Dry a Green a 
mm inch  mm inch  mm inch  mm inch  
Boards  3/8 
1/2 
5/8 
3/4 
1 
1-1/4 
1-1/2 8 
11 
14 16 
19 
25 
32 5/16 
7/16 
9/16 
5/8 
3/4 
1 
1-1/4 9 
12 15 17 
20 
26 
33 11/32  
15/32  
19/32  
11/16  
25/32  
1-1/32 
1-9/32 2 
3 
4 
5 
6 
7 
8 
9 
10 
11 
12 
14 
16 38 
64 
89 
114 
140 
165 
184 
210 
235 
260 
286 
337 
387 1-1/2 
2-1/2 
3-1/2 
4-1/2 
5-1/2 
6-1/2 
7-1/4 
8-1/4 
9-1/4 
10-1/4 
11-1/4 
13-1/4 
15-1/4 40 
65 
90 
117 
143 
168 
190 
216 
241 
267 
292 
343 
394 1-9/16 
2-9/16 
3-9/16 
4-5/8 
5-5/8 
6-5/8 
7-1/2 
8-1/2 
9-1/2 
10-1/2 
11-1/2 
13-1/2 
15-1/2 
Dimension  2 
2-1/2 
3 
3-1/2 
4 
4-1/2 38 
51 
64 
76 
89 
102 1-1/2 
2 
2-1/2 
3 
3-1/2 
4 40 
52 
65 
78 
90 
103 1-9/16 
2-1/16 
2-9/16 
3-1/16 
3-9/16 
4-1/16 2 
2 1/2  
3 
3 1/2  
4 
4 1/2  
5 
6 
8 
10 12 
14 
16 38 
51 
64 
76 
89 
102 
114 
140 
184 
235 
286 
337 
387 1-1/2 
2 
2-1/2 
3 
3-1/2 
4 
4-1/2 
5-1/2 
7-1/4 
9-1/4 
11-1/4 
13-1/4 
15-1/4 40 
52 
65 
78 
90 
103 
117 
143 
190 
241 
292 
343 
394 1-9/16 
2-1/16 
2-9/16 
3-1/16 
3-9/16 
4-1/16 
4-5/8 
5-5/8 
7-1/2 
9-1/2 
11-1/2 
13-1/2 
15-1/2 
Timbers  5 & 6 
thick  13 off  1/2 off  13 off  1/2 off  5 & 6 
wide  13 off  1/2 off  13 off  1/2 off  
7-15 thick  19 off  3/4 off  13 off  1/2 off  7-15 wide  19 off  3/4 off  13 off  1/2 off  
>=16 
thick  25 off  1 off 13 off  1/2 off  >= 16 
wide  25 off  1 off 13 off  1/2 off  
 
a See 2.7 and 2.11 for the definitions of dry and green lumber.  
 16 Table 4. Nominal and minimum -dressed sizes of worked lumber.  
 
The thicknesses apply to all widths and all widt hs apply to all thicknesses. Sizes are given in millimeters and inches. 
Metric units are based on dressed size. See B1, Appendix B for roun ding rule for metric units.  
 
Item  Thicknesses  Widths  
Nom inal 
Inch  Minimum Dressed  Nom inal 
Inch  Minimum Dressed  
Drya Greena Drya Greena 
mm inch  mm inch  mm inch  mm inch  
Shiplap,  
10 mm (3/8 inch) 
lapb 1 19d 3/4d 20 25/32 4 
6 
8 
10 12 14 
16 79 
130 175 
225 
276 327 
378 3-1/8 
5-1/8 
6-7/8 
8-7/8 
10-7/8 
12-7/8 
14-7/8 81 
133 181 
232 
283 333 
384 3-3/16 
5-1/4 
7-1/8 
9-1/8 
11-1/8 
13-1/8 
15-1/8 
Shiplap,  
13 mm (1/2 inch) 
lap b,c 1 
2 
2-1/2 
3 
3-1/2 
4 
4-1/2 19d 
38 51 64 76 
89 
102 3/4d 
1-1/2 
2 
2-1/2 
3 
3-1/2 
4 20 
40 
52 65 78 
90 
103 25/32  
1-9/16 
2-1/16 
2-9/16 
3-1/16 
3-9/16 
4-1/16 4 
6 
8 
10 
12 
14 
16 76 
127 
171 222 273 
324 
375 3 
5 
6-3/4 
8-3/4 
10-3/4 
12-3/4 
14-3/4 78 
130 
178 229 279 
330 
381 3-1/16 
5-1/8 
7 
9 
11 13 
15 
Cente rmatch 
(Tongue & 
Groove),  
6 mm (1/4 inch) 
tongueb 1 
1-1/4 
1-1/2 19d 
25 
32 3/4d 
1 
1-1/4 20 26 33 25/32 
1-1/32 
1-9/32 4 
5 
6 
8 
10 
12 79 
105 130 
175 
225 
276 3-1/8 
4-1/8 
5-1/8 
6-7/8 
8-7/8 
10-7/8 81 
108 133 
181 
232 
283 3-3/16 
4-1/4 
5-1/4 
7-1/8 
9-1/8 
11-1/8 
Cente rmatch 
(Tongue & 
Groove),  
10 mm (3/8 inch) 
tongue c 2 
2-1/2 
3 
3-1/2 
4 
4-1/2 38 
51 
64 
76 89 
102 1-1/2 
2 
2-1/2 
3 
3-1/2 
4 40 
52 
65 
78 90 
103 1-9/16 
2-1/16 
2-9/16 
3-1/16 
3-9/16 
4-1/16 4 
6 
8 
10 12 76 
127 
171 
222 273 3 
5 
6-3/4 
8-3/4 
10-3/4 78 
130 
178 
229 279 3-1/16 
5-1/8 
7 
9 
11 
Grooved -for-
Splines  2-1/2 
3 
3-1/2 
4 
4-1/2 51 
64 76 
89 
102 2 
2-1/2 
3 
3-1/2 
4 52 
65 
78 
90 
103 2-1/16 
2-9/16 
3-1/16 
3-9/16 
4-1/16 4 
6 
8 
10 
12 89 
140 
184 
235 
286 3-1/2 
5-1/2 
7-1/4 
9-1/4 
11-1/4 90 
143 
190 
241 
292 3-9/16 
5-5/8 
7-1/2 
9-1/2 
11-1/2 
 
a  See 2.7 and 2.11 for the definitions of dry and green lumber.  
 
b  In worked lumber less than nominal 2 -inch thickness, the tongue shall be 6 mm (1/4 inch) wide in tongued and grooved lumber and 
the lap shall be 10 mm (3/8 inch) or 13 mm (1/2 inch) wide in shiplapped lumber, with the over -all widths 6 mm (1/4 inch), 10 
mm (3/8 inch) and 13 mm (1/2 inch) wider, respectively, than the face widths shown in the above t able.  
 
cIn worked lumber of nominal 2 -inch and greater thickness, the tongue shall be 10 mm (3/8 inch) wide in tongued -and-grooved lu m-
ber and the lap shall be 13 mm (1/2 inch) wide in shiplapped lumber, with the over -all widths 10 mm (3/8 inch) and 13 mm ( 1/2 
inch) wider, respectively, than the face widths shown in the above table.  Double tongued -and-grooved decking shall be manufa c-
tured with a 10 mm (3/8 inch) or 8 mm (5/16 inch) wide tongue.  
 
d  Alternate minimum dressed dry thickness for 1 -inch nominal center- match and shiplap is 18 mm (23/32 inch).  
 
 17 6.  GRADING RULE REQUIREMENTS  
 
6.1 General concepts  
 
6.1.1  Grading parameters --To the extent to 
which di fferences in the characteristics of species, 
in the quality of logs, in conditions of manufacture 
and in the uses to which the product is put will 
permit, the basic provisions for the grading of 
lumber shall be uniform. The grading of lumber cannot be considered an exact science because it is based on either a visual inspection of each piece 
and the judgm ent of the grader or on the results 
of a method of mechanically determining the 
strength characteristics of structural lumber [see 6.3.2.2]. Grading rule provisions shall be suff i-
ciently explicit to establish 5 pe rcent below grade 
as an allowable variation between qualified grad-
ers. If any grading rules indicate that a grade qualifies under two use classifications, the grade provisions shall satisfy the r equirements for both 
classifications.  
 
6.1.2  Minimum grade requirements-- The 
method of determining the extent and limitations 
of the characteristics permitted in the poorest pieces admissible in each grade of lumber shall be stated in a certified rule, except in the lowest 
grade of each classification. Since lumber grades 
are broad manufacturing categories, grades ove r-
lap and pieces are selected from a grade to co m-
prise another grade outside of that grade categ o-
ry. A specific shipment shall not be made up of o n-
ly pieces containing characteristics of the max i-
mum number or size permi tted in the grade.  
 6.1.3  Grade ch aracteristics  -Characteristics 
permi tted and limitations for rough lumber shall 
be the same as those prescribed in grading rules for dressed lumber of the same grade and, in add i-
tion, such others as will disappear in standard 
dressing shall be allowed. If charac teristics other 
than those described in certified grading rules are 
encountered, they shall be evaluated in relation to 
the characteristics permitted or limitations pre-scribed for the grade under consideration and shall be allowed if r egarded as equi valent or less 
damaging in effect on the strength, appearance, or other utility value of the piece. In all grades, the 
size of allowable characteristics shall not exceed 
that specified in the respe ctive grading rules.  
 Note:  In many grades, the size of permitted char-acteri stics varies in proportion to the size of a face 
or the area of a cross section of the piece.   
 
6.1.4  Special provisions --When heartwood, 
sapwood, grain classifications, and other optional 
provisions are specified, and the lumber conform s 
to the requirements of such special provisions as 
well as to the regular grade designated, it shall be  
regarded as of standard quality.  
 
6.1.5  Mixed grades --Mixed grades other than 
the two highest established grades for each gra d-
ing rule category shall n ot be included in certified 
grading rules.  
 6.1.6  Nonstandard grades --When nonstand-
ard grades, sizes, or patterns are specified, or when particular provisions of a standard grade 
are waived or changed, inspection shall be made 
accordingly, but all of the other provisions of the certified grading rules shall apply.  
 6.2 Seasoning provisions  
 6.2.1  General —The grading rules shall i n-
clude prov isions regulating lumber seasoning and 
moisture content. The provisions shall be devel-
oped by each geographical region for each species based on its own conditions and the requirements of the users of its products subject to the other provisions of Section 6. Provisions shall be ex-
pressed in terms of maximum moisture content 
allowed in each piece of lumber and determined in 
accordance with ASTM D 4444 Standard Test Method for Laboratory Standardization and Cal i-
bration of Hand- Held Moisture Meters and ASTM 
D 7438 Standard Practice for Field Calibration 
and Application of Hand -Held Moisture Meters as 
appropriate . The restrictions on the moisture co n-
 18 tent of seasoned lumber shall apply at the time of 
shipment, at the time of dressing (if dressed lu m-
ber is involved), and at the time of any reinspec-
tion (if moisture content is involved in the rein-
spection), as provided in the appl icable grading 
rules.   Any piece exceeding the allowable moisture 
content of the applicable grade provisions shall be 
considered out of compliance.  
 
6.2.2  Grading rules--The grading rules for 
each species or region shall include clear defin i-
tions for dry lumber under nominal 5- inch thic k-
ness [see 2.7]. The definitions shall be based on a 
maximum moisture content of 19 percent or less.  
The choice to grade and grade mark any item as green ALS program lumber or dry ALS program lumber shall be determined by ea ch rules writing 
agency in accordance with its own conditions [see 
2.7, 2.11, and 2.13 ]. 
 
6.2.3  Dry size requirements--The grading 
rules shall require lumber under nominal 5 -inch 
thickness sold as dry to be 19 percent or less in 
moisture content at the time of d ressing, and to be 
not less than ALS minimum dry dressed thick-
ness and width at 19 percent moisture content, or at such lower maximum -moisture content as may 
be applicable to the lumber at the time of dres s-
ing. The minimum -dressed dry sizes are shown in 
tables 1, 2, 3 and 4.  
 6.2.3.1   Shrinkage or expansion from dry 
size – Shrinkage or expansion that occurs after 
dressing to standard dry size shall be recognized 
through the allowance of a tolerance below or above minimum standard dry sizes on a basis of 1 percent shrinkage or expansion for each four 
percentage points of moisture content change or 
0.7 percent shrinkage or expansion for each four 
percentage points of moisture content change for Redwood, Western Red Cedar, and Northern 
White Cedar. The shrinkag e or expansion pe r-
centages are average values. Shrinkage or e x-pansion of individual pieces may vary.
4 Shrin k-
age allowances are determined assuming max i-
mum allowable moisture content at the time of 
surfa cing. Expansion allowances are determined 
assuming a t ypical equilibrium moisture content 
or other suitable reference moisture content.  
 
6.2.4  Size differentials --When the grading 
rules in any region permit lumber less than nom i-
nal 5- inch thickness to be dressed green, the rules 
shall require that the lumber be dressed to sizes 
specifically stated a ccording to both thickness and 
width, as set forth in ta bles 3 and 4.  
 6.2.5  Green size requirements--The mini-
mum dressed green sizes specifically stated in the 
rules shall be not less than the green sizes
5 shown 
in tables 3 and 4, except for Redwood, Western 
Red Cedar, and Northern White Cedar. For these three species, the following minimum dressed green thicknesses shall apply: 17 mm (21/32 inch) 
for corresponding nominal 3/4  inch dry, 20 mm 
(25/32 inch) for nominal 1- inch, 40 mm (1- 9/16 
inch) for nominal 2 -inch, 52 mm (2- 1/16 inch) for 
nominal 2- 1/2 inch, 65 mm (2- 9/16 inch) for nom i-
nal 3- inch, 78 mm (3- 1/16 inch) for nominal 3- 1/2 
inch, 90 mm (3- 9/16 inch) for nominal 4 -inch, and 
103 mm (4- 1/16 inch) for nominal 4 -1/2 inch. The 
following minimum green dressed widths shall apply: 65 mm (2- 9/16 inch) and 90 mm (3- 9/16 
inch) for nominal 3 -inch and 4- inch, 116 mm (4-
9/16 inch), 141 mm (5- 9/16 inch), and 167 mm (6 -
9/16 inch) for nominal 5- inch, 6- inch, and 7 -inch, 
4 The range of shrinkage of individual pieces from exper i-
mental observation is from 2% to 7%.  Variables that af-
fect measurement and shrin kage of lumber are: density, 
species, grain orientation and allowable grade charac-
teristics.   See Forest Products Laboratory Research 
Reports 15 and 30.  
5 The minimum green sizes are based on shrinkage factors 
of 2.35 percent in thickness and 2.80 percent  in width 
from the fiber saturation point to a 19 percent max i-
mum moisture content with recognition given to man u-
facturing practices and the differences in shrinkage characteristics between species of lumber or species groups of lumber.  
 19                                                            187 mm (7 -3/8 inch), 238 mm (9- 3/8 inch), 289 mm 
(11-3/8 inch) for nominal 8- inch, 10- inch, and 12-
inch, 341 mm (13- 7/16 inch) and 392 mm (15- 7/16 
inch) for nominal 14- inch and 16- inch.  
 
6.2.5.1  Shrinkage or expansion from green 
size – Shrinkage that occurs af ter dressing to 
standard green size shall be recognized through 
the allowance of a tolerance below minimum 
standard green sizes on a basis of 1 percent shrinkage for each four percentage points of moisture content below 30 percent or 0.7 percent 
shrinkage for each four percentage points of 
moisture content below 30 percent for Redwood, 
Western Red Cedar, and Northern White Cedar. Expansion allowances are deter mined assuming 
a typical equilibrium moisture content or other suitable reference moisture content.  The shrink-
age or expansion percentages are average values. Shrinkage or expansion of individual pieces may vary.
6 
 6.2.6  Grade marking (grade stamping) --
Grading rules that provide for grade marking of lumber less than nominal 5- inch thickness shall 
contai n a provision for standardized marking so 
as to indicate whether the lumber was green or dry at time of dressing. The standardized mark 
shall be S -GRN if surfaced green, S- DRY if su r-
faced dry, or KD if kiln dried to a maximum moi s-
ture content of 19 percent at time of surfacing. 
Moisture -content limits of less than 19 percent 
maximum moisture -content for dry or kiln dried 
shall only be specified if included in rules certified 
by the Board. For lumber of nominal 5- inch or 
greater thickness, other moisture -content limits 
shall be specified only if included in rules certified 
by the Board.  
 
6 The range of shri nkage of individual pieces from exper i-
mental observation is from 2% to 7%.  Variables that af-
fect measurement and shrinkage of lumber are: density, 
species, grain orientation and allowable grade charac-
teristics.  See Forest Products Laboratory Research R e-
ports 15 and 30.  6.3 Use classification provisions for vis-
ual grad ing 
 
6.3.1  Yard lumber  
 
6.3.1.1  Grade classifications --The grading of 
surfaced yard lumber is based upon the uses for 
which t he particular grade is designed and is a p-
plied to each kind with reference to its size and 
length when graded without consideration to fu r-
ther manufacture. On the basis of quality, the basic grade classifications of yard lumber shall be 
as follows:  
 (a)  S elect: Lumber for natural and paint fi n-
ishes.   
 (b)  Common: Lumber for general constru c-
tion and utility purposes.  
 
6.3.1.2  Yard lumber sizes --The dressed thic k-
nesses and widths of yard lumber as specified in 
3.4, 5.1 and 5.2 shall be considered as minimum standar ds for the corre sponding nominal sizes as 
shown.  
 
Note: Lumber of standard size, rough or dressed, may be described by its nominal dimension providing dressed sizes are shown on invoices and other documents.  
 6.3.1.3  Bundled lumber --Each length of bun-
dled lumber, except end -matched lumber, beveled 
siding, and bungalow siding shall be bundled se p-
arately unless ot herwise specified.  
 6.3.1.4  Finish and boards--In shipments of 
rough finish/selects and boards, pieces 13 mm (1/2 inch) or greater than the nominal inch- unit thic k-
ness, such as are produced by uneven sawing, shall, at the option of the buyer, be rejected or be accepted as of the next lower grade.  
 
6.3.1.5  Grading faces --Yard lumber other than 
timbers and dimension [see 6.3.2.3] shall be grad-
ed from th e face or best side only unless ot herwise 
specified.  
 
 20                                                            6.3.1.6  Fencing – Sawn boards used in the 
constru ction of fences may be square -top, dog -
eared, square -edge or tongue and groove. The 
tolerance in sawing of such boards shall not ex-
ceed 1.6 mm (1/16 inch) over or under the invoice thickness.  
 
6.3.2  Structural lumber  
 
6.3.2.1  Development of design values --
Design va lues contained in grading rules shall be 
developed in a ccordance with appropriate ASTM 
standards and other technically sound criteria. 
The National Inst itute of Standards and Techno l-
ogy, with the advice and counsel of the U.S. Forest 
Products Laboratory, shall be the final authority as to the appropriateness of such standards or cr i-
teria. The Board shall seek the assistance of the 
U.S. Forest Products Lab oratory in reviewing d e-
sign values set forth in grading rules and, in the 
case of each set of grading rules submitted for cer-tification, the Board shall obtain a report from the Laboratory evaluating whether  the procedures 
used in developing the claimed va lues are in a c-
cordance with the standards and criteria de-scribed herein. Rules -writing agencies shall make 
available upon request an explanation of the means by which the claimed values were d erived. 
When more than one rules -writing agency has r e-
sponsibility for writing grading rules for a given species, a group of species, or a geographical su b-
division of a species or of a group of species, a common set of strength and stiffness values shall 
be used by the agencies involved for that species, 
subdivision, or group of species in the interest of uniformity and sta ndardization.  
 
6.3.2.2  Grading --mechanical --The grading of 
structural lumber by mechanical means is reco g-
nized as an acceptable method of grading.  When 
graded by mechanical means all such grading 
equipment and methods shall be subject to ap-
proval and certification by the Board.  
 6.3.2.3  Grading faces --Timbers and dimension 
shall be graded from all four faces.   6.3.3  Factory and shop lumber  
 
6.3.3.1  Grade classification  - The grade class i-
fications of f actory and shop lumber shall be those 
promu lgated by the agencies which formulate and 
publish grading rules and which have been cert i-
fied by the Board.  
 
6.3.3.2  Grade characteristics --Factory and 
shop lumber shall be graded with reference to its use for doors and sashes, or on the basis of chara c-
teristics affecting its use for general cutup pu r-
poses, or on the basis of size of cutting. Its grade 
shall be determined by the percentage of the area 
of each board or plank available in cuttings of specified or of  given minimum size and qualities 
and shall be determined from the poor face based 
on the qual ity of both sides of each cutting.  
 
6.3.3.3  Grade sizes -- The ALS program grade 
sizes for factory and shop lumber shall be those 
promulgated by the agencies which  formulate and 
publish grading rules and which have been cert i-
fied by the Board.  
 6.3.3.4  Warped lumber --The cuttings in 
warped lumber shall be so laid out as to surface 
two sides to standard thickness and have straight 
edges parallel to the edges of the b oard or plank.  
 7.  GRADE MARKING (GRADE STAMPING)  
7.1 Agency procedures --Each accredited 
agency shall submit procedures with respect to 
grade marking to the Board for approval.  
 
7.2 Agency symbol --Each accredited age n-
cy shall maintain a bona fide supervi sory inspec-
tion service under which each mill authorized to 
use the registered symbol of the accredited agen-cy
7 in conjunction with the grade mark will be i n-
7 Facsimiles of the grade marks of the grading and inspe c-
tion agencies that are accredited by the Board of the 
ALSC, Incorporated, are available on the web at 
 21                                                            spected regularly as to grading efficiency and co n-
formity to all the agency established rules for 
grade marking.  
 
7.3 The Grade mark (grade stamp) --
When ALS program lumber is grade marked, the grade marking shall be subject to the following 
provisions:  
 
7.3.1  The grade mark shall signify that the 
lumber co nforms to the size, grade and seasoning 
provisions of the rules under which it is graded. 
When green lumber of less than nominal 5- inch 
thickness is graded and grade marked under the 
applicable grading rules [see also 6.2.6], it shall comply with the green size requirements of such rules. If lumber is d ressed to a size below the mi n-
imum size requirements shown in Tables 1- 4 or 
below the minimum sizes set forth in the applic a-
ble grading rules, the mark shall show that size, and if less than of nominal 5- inch thic kness, shall 
state whether the lumber was d ry or green when 
dressed.  
 
7.3.2  A distinguishable mark or insignia, re g-
istered and symbolizing grading supervision by an accredited agency, shall be used in conjunction with the grade mark for each agency. Facsimiles 
of the grade marks of the grading and inspection 
agencies that are accredited shall be available to specifiers, purchasers and consumers.
8 
 7.3.3  All pieces and/or bundles of a given grade 
shall be grade marked.   Bundled lumber is d e-
fined as a small number of boards or strips bound by some met hod, such as shrink wrap, 
string or similar binding, so as to form a small package.  
 
www.alsc.org  or from the ALSC, I ncorporated,  P.O. Box 
210, Germantown, MD 20875 -0210. Telephone (301) 
972-1700, Fax (301) 540- 8004.  
8 Ibid.  7.3.3.1  Except for bundled lumber, the mixing of 
grade marked and non- grade marked lumber in 
the same package shall not be permitted.     
 7.3.4  Mixed grades, other than th e two highest 
recognized grades for each grading rule category, 
shall not be grade marked with a combination 
grade designation.  
 
7.3.5  The grade mark for lumber shall include 
an ident ification or designation of the commercial 
name of the species [see Appendix A] from which 
the lumber was produced. The identification of 
species shall not be required when the agency 
symbol also indicates the species from which the lumber was produced. Where grading rules co n-
tain provisions for the grouping of species, each individual species included in a group shall be 
identified in the rules, and the grade mark  shall 
include the designation a ssigned to the group.  
 7.3.6  These provisions are not intended to pr e-
clude the inclusion of additional regulations by an 
agency regard ing the use of its grade mark pr o-
vided the basic provisions of this section are ob-
served.  
 7.3.7  Remanufacture ( ripping , resawing or 
surfacing ) of graded or grade marked lumber n e-
gates the grade or grade mark and the design va l-
ues of the original prod uct and the original grade 
mark shall be removed, by any appropriate 
means . 
 
7.3.7.1  When grade marked dimension lumber is 
resawn or remanufactured in such a way as to p o-
tentially alter the grade indicated by the grade 
mark, the original grade mark shall be oblitera t-
ed. 
 
8.  INSPECTION AND REINSPECTION  
 
8.1 Inspection  
 
8.1.1  Agency certification and supervi-
sion--When ALS program lumber is grade 
 22                                                                                                      marked, the grade marking shall be under the d i-
rection, including regular gra ding supervision at 
mills, of an agency accredi ted by the Board as b e-
ing competent and having adequate facilities for 
such s upervision.  
 8.1.2  Delegation of grading authority--
Permission to grade mark shall be delegated only 
by an agency accre dited by the Board to operate a 
mill supervisory service to those mills which have 
demonstrated and proven their ability to conform 
to and are currently in conformance with the 
grading rules for the species and grades which 
they manufacture. The mill shall also agree to 
maintain the established standards of size and grade and to submit its lumber to inspection by the supervisory agency both at the mill and upon complaint at destination.  
 8.1.3  Payment--certificate costs --When an 
accredited agency issues a certificate on a shi p-
ment, the party requesting the certifica te shall 
pay for the cost thereof.  
 
8.1.4  Service --Inspection service shall be r e-
quired for the inspection of grades not described in the rules only when written detailed specific a-
tions accompany the re quest for such inspection. 
For the inspection of stand ard grades in no n-
standard sizes, inspection service shall be r e-
quired based on 6.1.6 unless otherwise prescribed in the contract of pu rchase and sale.  
 
8.2 Reinspection 
 
8.2.1  General --Subject to freedom of agre e-
ment between buyer and seller as to the sett le-
ment of complaints, the purchase, sale, or shi p-
ment of ALS program grades of lumber shall be construed as involving agreement to submit lu m-
ber to reinspection by an accredited inspection 
agency under published rules by which the lum-
ber was graded [see 8. 2.4]. Grading rules shall i n-
clude provisions for reinspection in case of com-plaint, and reinspection shall be available to any-one at reaso nable cost.   8.2.2  Complaints --Grade complaints on lu m-
ber shall be recognized only when the  lumber is in 
the form in w hich it was shipped. Any subs equent 
change in manufacture, working, or through kiln -
drying shall relieve the seller of responsibility for any grade complaints.  
 
8.2.3  Buyer's responsibilities--In case of a 
complaint, the buyer shall accept that portion of 
the shipment that is of the grade, size, and mois-
ture content specified and shall hold intact that portion which is disputed for inspection or rei n-
spection. Any action on the part of the buyer in 
accepting and using such portion of the shi pment 
that is of the grade, size, and moisture content 
specified shall not be construed as the acceptance of the entire shipment. The buyer shall hold the 
disputed lu mber intact, properly protected, for not 
more than 30 days after the date of the request for 
inspection or reinspection. The buyer shall file a 
complaint with the seller within the time specified 
in 8.2.6 and 8.2.7. The buyer shall pay in accor d-
ance with the terms of the sale for that portion a c-
cepted, but acceptance of a part of a shipment 
does not prejudice t he buyer’s just claims that any 
unused lumber does not meet the specifications of 
the grade, size, or moisture con tent.  
 8.2.4  Seller's responsibilities--Upon receipt 
of a co mplaint from the purchaser, the seller shall 
immediately request the agency under whose rules shipment has been made, or such other 
agency that was agreed upon, to provide inspe c-
tion, reinspection or retally as required a ccording 
to the grading rules in effect at the time of exec u-
tion of the contract.  
 8.2.5  Cost and assistance --The exp ense of 
such inspection, reinspection, or retally shall be 
borne in acco rdance with the inspection provisions 
of the applicable grading rules, but the person calling for the reinspection shall be responsible to 
the agency for the costs thereof. The purchas er 
shall lend all reasonable assistance to facilitate 
the inspection, rein spection or retally.  
 23  
8.2.6  Tally, grade, and size complaints --In 
case of a complaint involving tally, the entire item 
shall be held intact for retally. In case of a com-
plaint regarding grade or size, but not involving tally, the buyer shall hold intact that portion of the item that is of the grade or size which is in 
dispute for inspection and shall file complaint 
with the seller within 10 days of date of receipt of 
the shipment.  
 8.2.7 Moisture content complaints --In case 
of a complaint involving moisture content, the 
buyer shall inform the seller of the complaint 
within 72 hours after the lumber is unloaded. In such cases, the seller shall answer such complaint within 72 hours from receipt of complaint. A rei n-
spection involving a complaint on moisture con-
tent shall be made in accordance with the prov i-
sions of the applicable grading rules. Each piece 
shall be tested for moisture content, and separ a-
tion shall be made of all pieces conf orming to the 
maximum allowable moisture content from any 
portion ex ceeding such maximum.  
 
8.2.8  Reinspection results--Each item of a 
shipment shall be considered as of the grade i n-
voiced if, upon reinspection under the grading 
rules under which the lumber  was graded and 
sold, 95 percent or more thereof is found to be of 
said grade or better. When degrades in grade or moisture content or both are in excess of 5 percent of the board footage of each item, or when they are 
more than one grade lower than the gr ade invoice, 
such degrades shall be kept separate and shall be 
the property of the seller unless otherwise agreed. These provisions shall not apply in the case of 
specially worked lumber.  
 
9.  AMERICAN LUMBER STANDARD COMMITTEE  
 9.1 Functions of ALSC --The functions of 
the ALSC shall be:  
 9.1.1  To act as the Standing Committee for the 
purpose of considering proposals for future rev i-
sions of or amendments to this Standard. When 
acting as the Standing Committee, the procedures 
for the development of Voluntary Produc ts Stan d-
ards of the US D epartment of Commerce shall be 
applicable. The Department of Commerce shall provide the secretariat and appoint a chairman 
for the Standing Committee.  
 
9.1.2  To cooperate with the U.S. Department 
of Commerce in establishing and maki ng continu-
ously available basic standards for lumber size, 
pattern, quality, inspection, and reinspection for 
use by i ndustry and trade.  
 
9.1.3  To determine the criteria by which the 
Board shall  adjudge and approve the following as 
being in conformance wit h this Standard:  
 
9.1.3.1  Any published rules.  
 
9.1.3.2  The competency, reliability, and adequ a-
cy of the facilities provided by agencies pu blishing 
grading rules for the purpose of lumber certifica-
tion, inspection, reinspection, and supervision of 
grade ma rking.  
 9.1.3.3  The competency, reliability, and adequ a-
cy of the facilities provided by non -rules writing 
agencies  participating in this program that do not 
publish grading rules.  
 9.1.4  To advise the Board with respect to the 
interpre tation or application  of this Standard  and 
the detailed requirements defined and established by the ALSC.  
 9.1.5  To fix, after consultation with the agen-
cies participating in the use of its facilities, such charges and fees as the ALSC finds to be nece s-
sary to cover the actual  cost, including reserves 
and provisions for contingencies, of carrying out its functions, those of the Board, and the NGRC. 
Such charges and fees shall be assessed at a uni-
form proportionate rate against the agencies pa r-
 24 ticipating in the use of the facilities of the ALSC. 
The accreditation of any agency not paying its as-
sessment within 60 days after notification by the 
Secretary of the ALSC shall be revoked by the 
Board.  
 9.2 Appointment of members  - The pri n-
cipal and alternate members shall be appointed 
by the Secretary of Commerce for terms of not less 
than two nor more than five years.  
 
9.3 Composition of ALSC --The following 
procedures shall apply in making appointments to 
the ALSC.  
 
9.3.1  A rules -writing agency is one that parti c-
ipates in this program a nd that formulates, pu b-
lishes, and maintains grading rules and mai n-
tains inspection facilities covering the various lumber species. Each rules -writing agency may 
nominate a principal and alternate for each me m-
ber allotted to that agency. Principal members and their alternates shall be appointed from the 
nominees furnished by each agency as follows:  
 
Agency  Members  
 Allotted  
Southern Pine Inspection Bureau  2 
Western Wood Products Association  2 
West Coast Lumber Inspection Bureau  2 
Redwood Inspection Service 1 
Northeastern Lumber Manufacturers  
Association  1 
Northern Softwood Lumber Bureau  1 
National Lumber Grades Authority  1 
Each other agency qualifying under  
this category  1 
 
9.3.2  A non -rules writing agency is one that 
participates in this program and that do es not 
publish grading rules. Each non- rules writing 
agency may nominate a principal and alternate member. Three principal members and their a l-
ternates shall be appointed from among the nom-
inees so furnished.   
9.3.3  Firms or organizations within lumber 
specifying, distributing, and consuming groups, at 
the request of the Secretary of Commerce, may nominate a principal and an alternate for each member allotted. Principal members and their a l-
ternates shall be appointed from those groups as 
follows:  
 
 Groups  Members  
  Allotted 
Lumber Distributors & Wholesalers  2 
Lumber Retailers  2 
Wood Using Industries  2 
General Contractors  1 
Home Builders  1 
Architects  1 
Engineers  1 
Wood Treating Industry  1 
 
9.3.4  The Secretary of Commerce may appoint 
consumer -at-large principa l members and their 
alternates to represent the general public.  
 
9.3.5  Each nomination shall be submitted to 
the Secretary of Commerce by the appropriate 
agency, firm, or organization upon request or whenever a vacancy occurs in the segment repr e-
sented. Ea ch nomination shall contain the follo w-
ing: 
 9.3.5.1  A summary of the qualifications of the 
nominee. 
 9.3.5.2  A statement of the method or procedure 
by which the nominee was selected and the proc e-
dures under which the nominee will exercise the responsibilit y of membership for the agency or i n-
dustry segment repre sented.  
 9.3.5.3  A statement of any interests, financial or 
otherwise, which the nominee has in agencies or segments of the industry other than the one the 
nominee represents.  
 
 25 9.3.5.4  For agencies s ubmitting more than one 
nominee, a listing in the order of priority for a p-
pointment.  
 
9.3.6  Ex officio, non -voting principal and a l-
ternate members may be appointed by the Secre-tary of Commerce from the following Federal 
agencies:  
 
 Department of Defense  
 Department of Agriculture 
 Department of Interior  
 General Services Administration  
 Department of Housing &  Urban Develop ment 
 National Institute of Standards &  Techno logy  
 
9.3.7  Balance of representation  - Upon re-
quest, the Secretary of Commerce may consider 
making changes in the constitution of the ALSC 
or making additional appointments to ensure that 
the ALSC has a balance of interest and is not 
dominated by a single interest category. In such considerations, the Secretary of Commerce shall 
consult the ALSC for advice regarding balance 
and the criteria by which it may be dete rmined.  
 
9.4 ALSC secretary--Except as provided in 
9.1.1, the manager or executive officer of the 
Board, employed as provided in 10.5, shall serve 
as the Secretary of the ALSC.  
 9.5 Transaction of business 
 
9.5.1  Meetings --A majority of the members of 
the ALSC representing agencies which formulate, 
publish, and maintain grading rules and maintain 
inspection facilities, together with a majority of 
the other members, shall constitute a quorum for 
the transaction of business. A vote of the majority 
of those present shall decide any question that 
comes before a meeting; but if at any meeting of 
the ALSC there shall be less than a quorum pr e-
sent, a majority of those present shall adjourn the 
meet ing or act on the subjects before it, subject to 
ratification in writing by the respective m ajorities 
which constitute a quo rum.   
9.5.2  Correspondence --Business that has 
not been previously presented at a meeting of the ALSC shall be held until the next meeting or 
transacted by corre spondence in accordance with 
rules to be established by the ALSC . 
 
10.  BOARD OF REVIEW  
 10.1 Autonomy of Board --The Board shall 
be an autonomous body functioning under by -laws 
approved by the ALSC and consistent with Se c-
tion 10.  
 
10.2 Composition, election, terms, com-
pensation, and removal  - The Board shall be 
composed of three members, none of whom shall 
be members of the ALSC or affiliated with an a c-
credited agency or any member of an accredited agency.  
 10.2.1  The chairman of the ALSC shall appoint 
a spokesperson for each of the three membership groups within the ALSC that shall each nominate 
one potential member of the Board. The spoke s-
person shall determine and report the deci sion of 
the group to the Chairman along with a sum mary 
of the qualifications of the nominee and a stat e-
ment of any interests, financial or otherwise, which the nominee has in the lumber industry. 
Board members shall be nominated as fo llows:  
 
10.2.1.1  One member by majority decision of 
those ALSC members r epresenting the accredited 
rules -writing agencies.  
 10.2.1.2  One member by majority decision of 
those members representing the accredited non -
rules -writing lumber inspection agencies.  
 10.2.1.3  One member by majority decision of 
those remaining ALSC member s representing 
other inter ests. 
 
10.2.1.4  The name of the nominee shall be sub-
mitted to the Department of Commerce prior to 
 26 election and shall be accomp anied by a summary 
of the qualifications of the nominee and an atte s-
tation that the requirements of 10.2  and 10.2.1 
have been met.  
 
10.2.2  Election --Board members shall be elec t-
ed by the members of the ALSC by a majority of 
those voting. In the event that a nominee desig-
nated under 10.2.1.1, 10.2.1.2 or 10.2.1.3 fails to 
receive a m ajority of the votes cast at any election, 
a new no minee shall be designated in accordance 
with the procedure set forth in 10.2.1.1, 10.2.1.2  
or 10.2.1.3.  
 
10.2.3  Terms --The three members of the Board 
shall be elected for terms, respectively, of three years, two years, and one year , or until their su c-
cessors are duly elected. Annually thereafter, one 
member shall be elected for a term of three years 
or until a successor is duly elected. Vacancies on the Board by reason of death, resignation, or r e-
moval shall be filled at any regular ly called com-
mittee meeting subject to the provisions of 10.2.1, 
10.2.2 and 9.5.2. Any person elected to fill a v a-
cancy shall serve the unexpired term of the pred e-
cessor.  
 
10.2.4  Compensation --The ALSC shall fix and 
pay compensation to the members of the B oard 
and shall reimburse them for all reasonable e x-
penses incurred in fu lfilling their duties.  
 10.2.5  Removal --The removal of any Board 
member shall require a vote of not less than two -
thirds of all the members of the ALSC, with the concurrence of the D epartment of Commerce.  
 
10.3 Board manager --The Board shall select 
and e mploy a salaried manager or other executive 
officer, subject to the approval of the ALSC, who 
shall assume the responsibilities and perform the 
duties delegated by the ALSC or the Board.  Such 
manager or executive officer shall not be in the 
employment of any lumber organization, comp a-
ny, or inspection agency while employed by the 
Board.   10.4 Certification functions--Upon applic a-
tion, the Board shall examine and certify the fol-
lowing as c onforming to the requirements of this 
Standard and to a dditional detailed requirements 
established by the ALSC: Grade strength ratios, 
nomenclature, descriptions of grades published by the NGRC and grading rules published by accre d-
ited, competent and relia ble agencies having ad e-
quate facilities for mill inspection and for rein-
spection of lumber (provided that no such rules for 
any species in any region shall be certified if cert i-
fied pu blished rules and service applicable thereto 
are adequate and already fully and fairly avail a-
ble to all manufacturers, distributors, and co n-
sumers of such lumber, on equal terms and cond i-
tions without discrimination). Certification shall be subject to these conditions:  
 10.4.1 Rules conform to the basic requirements 
of this St andard.  
 10.4.2  Published rules carry specific refer ences 
to such certification.  
 
10.4.3 The originating agency shall make the 
rules fully and fairly available to all manufactu r-
ers, distrib utors, users, and consumers of lumber 
on equal terms and conditions  and without di s-
crimi nation.  
 
10.4.4 Subsequent revisions made by the pro m-
ulgating agency to grading rules that have been certified by the Board shall be acted upon within 
90 days after sub mission to the Board.  
 10.4.5 Grading rules of an agency shall not be 
certified as conforming to this Standard if the Board determines the dimension lumber rules 
therein fail to conform to the provisions of the N a-
tional Grading Rule for dimension lumber esta b-
lished pursuant to Section 11 of this Standard.  
 
10.5 Accreditation functions--Upon appl i-
cation, the Board shall examine and accredit rules -writing agencies and non -rules -writing 
 27 agencies as conforming to the r equirements of this 
Standard and to additional requirements esta b-
lished by the ALSC. Accreditation shall be su bject 
to these conditions:  
 
10.5.1 The competency, reliability, and adequ a-
cy of the facilities provided by agencies participa t-
ing in this program for the purposes of lumber 
certification, inspection, reinspection, or superv i-
sion of grade marking.  
 
10.5.2 The adequacy of the procedure followed 
in authorizing mills to grade mark when provid-
ing adequate supervisory service.  
 
10.5.3 The continuing conformance of grading 
rules to this Standard.  
 
10.5.4 The continuing competency and adequa-
cy of performance of ag encies.  
 
10.6 Withdrawal of accreditation --If at 
any time the practices of any accredited agency 
are found not in conformity with this Standard 
and other requirements adopted by the ALSC, 
and if, after due notice in writing to that effect, according to established procedures, those pra c-
tices shall not have been brought into conformity 
with such standards and other requirements by 
the agency concerned, the Board is empowered to revoke all previous accreditation granted that agency.  
 
10.7 Actions of Board --In all actions in rela-
tion to the certification of grading rules, accredit a-
tion of agencies and inspection facilities, and 
grade marking practices, the Board shall proceed 
in a fair and nondiscriminatory manner giving 
full and due consideration to the past e xperience 
and performance of agencies seeking accredita-tion, and shall apply uniform standards of jud g-
ment in making all determinations. In the matter 
of inspection agencies, definite requirements as to 
the integrity, competency and adequacy of the agency,  and the adequacy of its facilities shall be 
established, but all such requirements shall be uniformly applied with respect to all agencies seeking accreditation from the Board. No inspe c-
tion agency that is controlled by any person or 
firm whose own produc ts are subject to its inspe c-
tion and certification shall be accredited. Inspec-
tion services furnished by buyers and users for i n-
spection of their own purchases shall not be a c-
credited by the Board.  
 
10.8 Availability of Board --The facilities of 
the Board s hall be available at all times on equal 
terms to any a ffected party. The Board's facilities 
shall also be available to all lumber inspection 
agencies, without favor or discrimination and 
without any requirement for joining or otherwise 
subscribing to any t rade association or su pporting 
any service or activity other than those of gra ding, 
standardization, grade marking, and inspection 
that fall within the jurisdiction of the Board.  
 
10.9 Enforcement --The Board shall adopt, 
subject to prior approval by the AL SC, and admi n-
ister rules, regulations, and sanctions to ensure 
the continued competency, reliability, and integr i-
ty of accredited agencies providing inspection se r-
vices.  
 
10.10  Board hearings --Any party affected by 
a decision or action of the Board shall  have the 
right to require the Board to hold a hearing at 
which such party may appear personally or be 
represented by counsel to present supporting ev i-
dence and argument of the party's position in a c-
cordance with procedures established by the 
Board.  
 10.11  Reports of action --The Board shall 
within 30 days following an official action make 
such off icial action public.  
 
11.  NATIONAL GRADING RULE COMMITTEE  
 
11.1 Autonomy of NGRC --The National 
Grading Rule Committee (NGRC) shall be an a u-
tonomous body functioning  under by -laws (provid-
 28 ing, among other things, for the appointment of 
subcommittees) approved by the ALSC. The b y-
laws shall be reviewed at least every 5 years and 
reaffirmed or revised, as appropriate.  
 
11.2 Functions of the NGRC --The NGRC 
shall establish,  maintain, and make fully and fai r-
ly available grade -strength ratios, nomencl ature, 
and descriptions of grades for dimension lumber conforming to this Standard. Grading rules of an agency shall not be certified as con forming to this 
Standard if the Board d etermines that the dime n-
sion lumber rules therein fail to conform to the 
provisions of the National Grading Rule for d i-
mension lumber established pursuant to this se c-
tion. 
 
11.3 Composition of NGRC --In the interest 
of obtaining balanced views, the NGRC shall be composed of persons representing the following that desire to partici pate:  
 
 Organization  Number of  
  Mem bers 
 Southern Pine Inspection Bureau  2 
 Western Wood Products Association  2 
 West Coast Lumber Inspection Bureau  2 
 Redwood Inspection Service 1 
 Northeastern Lumber Manufacturers  
Association, Inc.  1 
 Northern Softwood Lumber Bureau  1 
 International Code Council 1 
 National Fire Protection Association  1 
 National Association of Home Builders  1 
 Canadian Inspection Agencies  1 
 American Society of C ivil Engineers  1 
 American Institute of Architects  1 
 Consumer Organizations  1 
 Lumber Wholesalers  1 
 Lumber Retailers  1 
 U.S. Non -rules Writing Agencies  2 
 Ex officio, non -voting members shall be appointed 
from the following Federal agencies that desire t o 
participate:   
 Department of Housing and Urban 
  Develop ment  1 
 Defense Logistics Agency  1 
 Forest Products Laboratory  1 
 National Institute of Standards and  
Technology  1 
 11.4 Appointment of members and 
chairman --Members of the NGRC shall be co m-
petent in th e field of lumber technology. Every 
five years each organization or group of organiz a-
tions desiring to participate and entitled to repre-sentation shall appoint a principal member and alternate for each member to which it is entitled. The ALSC shall appoint  the principal member 
and alternate representing consumer organiz a-
tions.   The Chairman of the NGRC shall be elec t-
ed every 5 years by the NGRC from among its members.  
 
11.5 Transaction of business— A majority 
of members representing rules -writing agencies 
and a m ajority of the other members shall const i-
tute a quorum to co nduct business. Each member 
shall have one vote. The majority vote of those present and voting at a meeting shall prevail.  
 
 12.  REFERENCES  
 
 
12.1 ASTM Standards
9 
 D9-12 Standard Terminology Relating to Wood  
and Wood Based Products  
 
D1165- 13 Standard Nomenclature of Commercial 
Hard woods and Softwoods  
 
9 ASTM Standards are available from ASTM International, 
100 Barr Harbor Drive, West Conshohocken, PA 19248-
2959; tel ephone (610) 832-9500; www.astm.org.  
 29                                                            D4444- 13 Standard Test Methods for Laboratory 
Standardization and  Calibration of Hand -
Held Moisture  
Meters 
 
SI10-02 IEEE/ASTM SI 10 American National 
Standard for Use of the International  
System of Units (SI): The Modern Metric 
System  
 
12.2 Other publications  
 
Little, Elbert, Jr., Checklist of United States Trees 
(Native and Naturalized) , Agriculture 
Handbook No. 541, Forest Service, U.S. 
Department of Agricu lture, Was hington 
DC 20090- 6090, 1979.  
 
 30 APPENDIX A  COMMERCIAL NAMES OF THE PRINCIPAL SOFTWOOD SPECIES  
 
The commercial names listed below are intended to provide a correlation between commercial names 
for lumber and the botanical names of the species from which the lumber is to be manufactured. In 
some instances more than one species is associated with a single commercial name. For stress -graded 
lumber, the species to be associated with a commercial name will be determined in accordance with 
6.3.2.1. These  commercial names are to be used in grading rule descriptions and in specifications [see 
2.15]. The provisions of this Standard apply to lum ber manufactured from hardwood species or lumber 
manufactured from foreign species when the species is included in r ules certified by the Board of R e-
view.   The information contained herein is a partial list of commer cial names of the principal softwood 
species and species groups. Additional species and species groups are provided in ASTM Standard D 1165- 13 and the rules  certified by the Board of Review.  
 
 Commercial  Official Common  
Species or Species Group Names10 Tree Names11 Botanical Names  
CEDAR:  
Alaska Cedar  Alaska -cedar  Chamaecyparis  
  nootkatensis  
Incense Cedar  incense -cedar  Libocedrus decurrens  
Port Orford Cedar  Port-Orford -cedar  Chamaecyparis  
  lawsoniana  
Eastern Red Cedar eastern redcedar  Juniperus virginiana  
 southern redcedar  J. silicicola  
Western Red Cedar  western redcedar  Thuja plicata  
Northern White Cedar  northern white -cedar  T. occidentalis  
Southern White Ce dar Atlantic white -cedar  Chamaecyparis thyoides  
 
CYPRESS12 
Baldcypress  baldcypress  Taxodium distichum  
Pond cypress  pond cypress  T. distichum var. nutans  
 FIR:  
Balsam Fir
13 balsam fir  Abies balsamea  
Fraser Fir  Fraser fir  A. fraseri  
Douglas Fir14  Douglas -fir Pseudotsuga menziesii  
10 The c ommercial names for species represent those commonly accepted. Some grading rules certified by the Board provide 
for the inclusion of additional species under the established names.  
 
11 The official common tree names conform to the Checklist of United State s Trees (Native and Naturalized) , Agriculture 
Handbook No. 541 (1979), and are sometimes used as names for lumber. In addition to the official common names for a 
species, the Handbook lists other names by which the species and the lumber produced from it are sometimes designated.  
 
12Cypress includes types designated as Red Cypress, White Cypress, and Yellow Cypress. Red Cypress is frequently classified 
and sold separately from the other types.  
 
13 Balsam fir lumber is sometimes designated either as Eastern fi r or as Balsam.  
 
14 Douglas fir from Arizona, Colorado, Nevada, New Mexico and Utah is recognized as Douglas fir-South.  
 31                                                             Commercial  Official Common  
Species or Species Group Names8 Tree Names9 Botanical Names  
FIR (continued)  
Bigcone Douglas fir  Bigcone Douglas fir  P. macrocarpa  
Noble Fir  noble fir  Abies procera  
Alpine Fir  subalpine fir (alpine fir)  A. lasiocarpa  
California Red Fir  California red fir  A. magnifica  
Grand Fir  grand fir  A. grandis  
Pacific Grand Fir  Pacific silver fir  A. amabilis  
White Fir  white fir  A. concolor  
 
HEMLOCK:  
Carolina Hemlock  Carolina hemlock  Tsuga caroliniana  
Eastern Hemlock  eastern hemlock  T. canadensis  
Mountain Hemlock  mountain hemlock  T. mertensiana  
Western Hemlock  western hemlock  T. heterophylla  
 JUNIPER:  
Western Juniper  alligator juniper  Juniperus deppeana  
 Rocky Mountain juniper  J. scopulorum  
 Utah juniper  J. osteosperma  
 western juniper  J. occidentalis  
 
LARCH:  
Western Larch  western larch  Larix occidentalis  
 
PINE:  
Bishop Pine Bishop pine Pinus muricata  
Digger Pine  Digger pine P. sabiniana  
Knobcone Pine  knobcone pine  P. attenuata  
Coulter Pine Coulter pine P. coulteri  
Jeffrey P ine  Jeffrey pine  P. jeffreyi  
Jack Pine  jack pine  P. banksiana  
Limber Pine limber pine  P. flexilis  
Lodgepole Pine  lodgepole pine P. contorta  
Norway Pine red pine  P. resinosa  
Pitch Pine  pitch pine  P. rigida  
Ponderosa Pine ponderosa pine  P. ponderosa  
Radiata/Monterey Pine Monterey pine P. radiata  
Sugar Pine  sugar pine  P. lambertiana  
Whitebark Pine  whitebark pine  P. albicaulis  
Idaho White Pine  western white pine  P. monticola  
Northern White Pine eastern white pine  P. strobus  
  
 
 
 32  Commercial  Official Common  
Species  or Species Group Names8 Tree Names9 Botanical Names  
PINE (continued) 
Longleaf Pine15 longleaf pine P. palustris  
 slash pine  P. elliottii  
Southern Pine (Major)  loblolly pine P. taeda  
 longleaf pine P. palustris  
 shortleaf pine  P. echinata  
 slash pine  P. elliottii  
Southern Pine (Minor)  pond pine  P. serotina   
 Virginia pine  P. virginiana  
 sand pine  P. clausa  
 spruce pine  P. glabra  
 
REDWOOD:  
Redwood  redwood  Sequoia sempervirens  
 
SPRUCE:  
black spruce  black spruce  Picea mariana  
red spruce  red spruce  P. rubens  
white spruce  white spruce  P. glauca  
Blue Spruce  blue spruce  P. pungens  
Engelmann Spruce  Engelmann spruce  P. engelmannii  
Sitka Spruce  Sitka spruce  P. sitchensis  
Norway Spruce     Norway spruce   P. abies  
 TAMARACK:  
Tamarack  tamarack  Larix laricina  
 
YEW:  
Pacif ic Yew  Pacific yew  Taxus brevifolia  
 
 
15 The commercial requirements for Longleaf Pine lumber are that not only must it be produced from trees of the botanical 
species of Pinu s elliottii  and Pinus palustris , but each piece in addition must average either on one end or the other not less 
than six annual rings per inch and not less than one -third summerwood. Longleaf Pine lumber is sometimes designated as 
Pitch Pine in the export  trade.  
 
 33                                                             
APPENDIX B  DEFINITIONS OF TERMS USED IN DESCRIBING  
STANDARD GRADES OF LUMBER  
 
 
B1. IEEE/ASTM SI 10-2002 was used as the 
authorit ative standard in developing the metric 
dimensions found in this Standard. Metric di-
mensions are calculated at 25.4 millimeters 
(mm) times the dressed dimension in inches. The 
nearest mm is significant for dimensions greater 
than 1/8 inch, and the nearest 0.1 mm is signif i-
cant for dimensions equal to or less than 1/8 inch.  
 
The rounding rule for dimensions greater than 
1/8 inch: if the digit in the tenths of mm position (the digit after the decimal point) is less than 5, 
drop all fractional mm digits; if greater than 5 or 
it is 5 followed by at least one non -zero digit, 
round one mm higher;  if 5 followed by only z e-
roes, retain the digit in the unit position (the 
digit before the decimal point) if it is even or in-
crease it one mm if it is odd.  
 
The rounding rule for dimensions equal to or 
less than 1/8 inch: if the digit in the hundredths of mm position (the second digit after the deci-
mal point) is less than 5, drop all digits to the right of the tenths position; if greater than 5 or it 
is 5 followed by at least one non -zero digit, round 
one-tenth mm higher; if 5 followed by only zeros, 
retain  the digit in the tenths position if it is even 
or increase it one- tenth mm if it is odd.  
 CAUTION: Use great care when converting 
board feet, based on NOMINAL cross -sectional 
dimensions, to cubic met ers of lumber, based on 
DRESSED cross -sectional dimensions. This is 
explained on page 32 of the IEEE/ASTM SI 10 -
2002 by the following note: “(9) No con version is 
given for “board foot” because “board foot” is not 
a well- defined unit of volume. Calc ulation of the 
number of board feet in a piece of lumber is based on the nominal dimensions of the cross 
section.”   
Unfortunately, many older handbooks and di c-
tionaries and some current references still con-
tain erroneous or vague information about vo l-
ume conversions to SI metric. The amount of 
dressing can also affect the cross -sectional d i-
mensions. Therefore, use extra care when ma k-
ing conversions from NOMINAL board foot to 
actual cubic meters.  
 In case of a dispute on size measurements, the 
conventional (inch) method of measurement 
shall take prec edence.  
 B2. Definitions of terms used in describ-
ing sta ndard grades of lumber:  
 
air dried --seasoned by exposure to the atmos-
phere, in the open or under cover, without 
artificial heat.  
 
all-heart --of heartwood throughout; that is, free 
of sa pwood.  
 
annual ring --denotes the amount of growth for 
a tree in a single year.  
 bark pocket --patch of bark partially or wholly 
enclosed in the wood. Classified by size the 
same as pitch pock ets. 
 
bevel siding —a board that has been resawn d i-
agonally to be used to clad the exterior of a 
buildi ng. 
rabbeted bevel siding —bevel siding 
with a rabbeted joint milled on the reverse of the thick edge to facilitate alignment of pieces.  
 
blemish --anything marring the appearance of 
lumber.  
 
 34 bow--see WARP.  
 
boxed heart --with the pith enclosed in the 
piece.  
 
bright --unstained.  
 
burl --a distortion of grain, usually caused by 
abnormal growth due to injury of the tree. 
The effect of burls is assessed in relation to knots.  
 
ceiling -a piece of patterned, tongue and grooved 
lumber, used to cover the ceiling of a room, 
porch or other partially enclosed areas.  
 check --a separation of the wood normally occu r-
ring across or through the annual rings and 
usually as a result of seasoning.  
roller check --a crack in the wood stru c-
ture caused by a piece of cupped lu m-
ber being f lattened in passing b e-
tween the machine roll ers. 
surface check --a separation that occurs 
on a face of a piece.  
small check --not over 0.8 mm (1/32 
inch) wide or 102 mm (4 inch) long.  
medium check --not over 0.8 mm (1/32 
inch) wide or 254 mm (10 inch) long.  
large check --over 0.8 mm (1/32 inch) 
wide or longer than 254 mm (10 inch) 
or both.   
through check --a separation that e x-
tends from one surface of a piece to 
the opp osite or adjoining surface.  
 
chipped grain --a barely perceptible irregular i-
ty in the surface o f a piece caused when pa r-
ticles of wood are chipped or broken below 
the line of cut. It is too small to be classed as torn grain and is not considered unless in ex-cess of 25  percent of the surface involved.  
 chip marks --shallow depressions or indent a-
tions on or in the surface of dressed lumber 
caused by shavings or chips getting embe d-
ded in the surface during dres sing. very light chip marks --not over 0.4 mm 
(1/64 inch) deep.  
light chip marks -not over 0.8 mm (1/32 
inch) deep.  
medium chip marks --not over 1.6 mm 
(1/16 inch) deep.  
heavy chip marks --not over 3.2 mm (1/8 
inch) deep.  
 
clear --free or practically free of all blemishes, 
characte ristics, or defects.  
 compression wood --abnormal wood that forms 
on the underside of leaning and crooked c o-
niferous trees. It  is characterized, aside from 
its distinguishing color, by being hard and 
brittle and by its relatively lifeless appea r-
ance. Compression wood shall be limited in 
effect to other appearance or strength redu c-
ing characteri stics permitted in the grade.  
 corne r--the intersection of two adjacent faces.  
 
crook --see WARP.  
 
cross break --separation of the wood across the 
width.  
 
crosscutting --cutting with a saw across the 
width.  
 
cup--see WARP.  
 
cutting --resulting pieces after crosscutting 
and/or ri pping.  
 decay (un sound wood) --a disintegration of the 
wood substance due to action of wood -
destroying fungi, and is also known as dote 
or rot.  
advanced decay --an older stage of decay 
in which disintegration is recognized 
because the wood has become punky, 
soft, spongy, str ingy, shaky, pi tted, or 
crumbly. Decided discoloration or 
bleaching of the rotted wood is often 
apparent.  
 35 heart center decay--a localized decay 
developing along the pith in some 
species and is detected by visual in-
spection. Heart center decay develops 
in the living tree and does not pr o-
gress further a fter the tree is cut.  
honeycomb --similar to white specks but 
the pockets are larger. Where permit-
ted in the grading rules, it is so li m-
ited that it has no more effect on the 
intended use of the piece than other  
charac teristics permitted in the same 
grade. Pieces containing honeycomb 
are no more subject to decay than 
pieces which do not contain it.  
incipient decay --an early stage of decay 
in which disintegration of the wood 
fibers has not pr oceeded far enough to 
soften or otherwise change the har d-
ness of the wood perceptibly. It is 
usually accompanied by a slight di s-
coloration or bleaching of the wood.  
peck --channeled or pitted areas or poc k-
ets found in cedar and cypress. Wood tissue between pecky areas remains unaffected in appearance and strength. All further growth of the 
fungus caus ing peckiness ceases after 
the trees are felled.  
pecky --characterized by PECK  
pocket rot --decay which appears in the 
form of a hole, pocket, or area of soft 
rot, usually sur rounded by apparently 
sound wood.  
water soak or stain --water -soaked area 
in heartwood, usually interpreted as the incipient stage of certain wood 
rots. 
white specks --small white or brown pits 
or spots in wood caused by the fungus 
Fomes pini .  It develops in the liv ing 
tree and does not develop further in 
wood in service. Where permitted in 
grading rules, it is so limited that it has no more effect on the intended 
use of the pieces than other charac-
teristics permitted in the same grade. 
Pieces containing white speck are no more subject to decay than pieces which do not co ntain it.  
 degrades --pieces which on reinspection prove of 
lower quality than the grade in which they were shipped.  
 
diagonal grain --a deviation in the slope of 
grain caused by sawing at an angle with the 
bark of the tree. See SLOPE OF GRAIN.  
 dry-- lumber of less than nominal 5- inch thic k-
ness which has been seasoned or dried to a 
maximum moisture content of 19 percent. 
Lumber of nominal 5- inch or greater in 
thickness (timbers) is often manufactured 
and sold without drying. When the max i-
mum moi sture content is specified for lumber 
of nominal 5 -inch or greater thickness, it 
shall be in accordance with the provisions of 
the applicable lumber grading rules cert ified 
by the Board, which for some species def ines 
dry lumber as having a maximum moisture 
content higher than 19 percent [see 2.7].  
 
eased edge --slightly rounded surfacing on piec-
es of lumber to remove sharp corners.  Note: 
Lumber nominal 4 inch or less in thickness is 
frequently shipped with eased ed ges unless 
otherwise specified.  
 edge --either : 1) the narrow face of rectangular -
shaped pieces, or 2) the corner of a piece at the intersection of two longitudinal faces, or 
3) in stress grades, that part of the wide face 
nearest the corner of the piece.  
 
edge grain (EG) [vertical grain (VG)] [rift 
grain] --a piece or pieces sawn at approx i-
mately right angles to the annual growth 
rings so that the rings form an angle of 45 
degrees or more with the surface of the piece.  
 
equilibrium moisture content  – the mo isture 
content at which wood neither gains nor los-
es moisture when surrounded by air at a gi v-
en relative humidity and temperature.  
 
 36 finish -a high- quality piece of lumber graded for 
appearance, often used for interior trim or 
cabinet work.  
 
firm red heart --a stage of incipient decay cha r-
acterized by a reddish color in the heartwood 
which does not render the wood unfit for the 
majority of yard pu rposes.  
 
flat grain (FG) [slash grain (SG)] --a piece or 
pieces sawn approximately parallel to the 
annual growth rings so that all or some of 
the rings form an angle of less than 45 d e-
grees with the surface of the piece.  
 
flooring -a tongue and grooved piece of lumber 
typically used as a finished floor.  
 f.o.h.c. (free of heart centers) --without pith 
(side cut). An occas ional piece, when showing 
pith for not more than 1/4 the length on the 
surface, shall be accepted.  
 
free of wane --without wane but with either 
eased or square edges. (see WANE)  
 
grain --the fibers in wood and their direction, 
size, a rrangement, appearance, or quality.  
 
green --lumber of less than nominal 5- inch 
thickness, which has a moisture content in 
excess of 19 percent. For lumber of nominal 
5-inch or greater thickness (timbers), green 
shall be defined in accordance with the pr o-
visions of the applicable lumber grading 
rules certified by the Board [See 2.11].  
 
gum pocket --an opening between growth rings 
which contains or has contained resin, or 
bark, or both.  
 
gum seam --check or shake filled with gum.  
 gum spot --an accumulation of gumlike sub-
stance occurri ng as a small patch. Often o c-
curs in conjunction with a bird -peck or other 
injury to the growing wood.  
 gum streak --a well- defined accumulation of 
gum in more or less regular streak. Class i-
fied as pitch streaks.  
 heart center--the pith or center core of th e log.  
 
heart face --face side free of sapwood.  
 
heart shake --see SHAKE --PITH SHAKE.  
 
heartwood --the inner core of the tree trunk 
comprising the annual rings containing non-
living elements. In some species, heartwood has a prominent color different from sa p-
wood. Heartwood and sapwood of equiv alent 
charac ter are compared as follows:  
with regard to strength , heartwood 
and sapwood are equal. No requir e-
ment of heartwood is made when strength alone is the gover ning factor.  
with regard to durability , heartwood 
is more du rable than sapwood. When 
wood is to be exposed to decay -
producing conditions without pre-servative treatment, it is permissible 
to specify the minimum percentage of 
heartwood to be present in all pieces 
of lumber in a shipment.  
with regard to preserv atives,  sapwood 
takes preservative treatment more 
readily than hear twood.  
 
hit-and- miss --a series of skips not over 1.6 mm 
(1/16 inch) deep with surfaced areas be-
tween.  
 hit-or-miss --lumber that is completely or partly 
surfaced or entirely rough with a max imum 
scantness of 1.6 mm (1/16 inch).  
 
holes --openings that either extend partially or 
wholly through a piece. An alternate desig-nation for holes which extend only partially through a piece is surface pits. Holes are 
class ified by size as follows:  
pin hol e--not over 1.6 mm (1/16 inch) in 
diameter.  
 37 medium hole --(small hole) not over 6 
mm (1/4 inch) in diameter.  
large hole --not over 25 mm (1 inch) in 
diameter.  
very large hole--over 25 mm (1 inch) in 
diameter.  
 
kiln-dried --seasoned in a chamber by means of 
artificial heat.  
 
knife marks --the imprints or markings of the 
machine knives on the surface of dressed 
lumber.  
very slight knife marks --marks that 
are visible only from a favorable angle 
and are perfectly smooth to the touch.  
slight knife marks --marks that are 
readily visible but evidence no un e-
venness to the touch.  
 
knot --a portion of a branch or limb that has be-
come incorporated in a piece of lumber. In 
lumber, knots are classified as to form, size, 
quality, and occurrence.  
 
 knot form-- 
oval knot --produce d when the limb is 
cut at slightly more than a right angle 
to the long axis.  
round knot --produced when the limb is 
cut at approximately right angles to 
its long axis.  
spike knot --produced when the limb is 
cut either lengthwise or diagonally.  
 
 knot size -- 
pin knot --not over 13 mm (1/2 inch) in 
diameter.  
small knot --not over 19 mm (3/4 inch) in 
diameter.  
medium knot --not over 38 mm (1- 1/2 
inch) in d iameter.  
large knot --over 38 mm (1- 1/2 inch) in 
diameter.  
 
 knot quality -- black knot --results from a dead bran ch 
which the wood growth of the tree has 
surrounded.  
decayed knot --softer than the surroun d-
ing wood, and containing advanced decay.  
encased knot --not intergrown with the 
annual rings of the surrounding wood.  
firm knot -solid across its face but co n-
tains inc ipient decay.  
fixed knot --retains its place in dry lu m-
ber under ordinary conditions but is movable under pressure though not 
easily pushed out.  
hollow knot --a sound knot containing a 
hole greater than 6 mm (1/4 inch) in diameter. The through opening of a 
hollow knot is limited to the size of 
other holes permitted.  
intergrown knot —a knot whose annual 
rings are partially or completely in-tergrown on one or more faces with the annual rings of the surrounding wood.  
loose knot --not firmly fixed; a knot not 
held t ightly in place by growth, shape, 
or position.  
pith knot --sound in all respects except it 
contains a pith hole not over 6 mm 
(1/4 inch) in diameter.  
red knot --knot that results from a live 
branch grown in the tree and is inte r-
grown with the sur rounding wood.  
sound knot --contains no decay.  
star-checked knot --has radial checks.  
tight knot--so fixed by growth, shape, or 
position that it retains its place in the piece.  
unsound knot --contains decay.  
water -tight knot--has annual rings 
completely intergrown with those of 
the surrounding wood on one surface of the piece, and it is sound on that 
surface.  
 
 knot occurrence -- 
 38 branch knots --two or more divergent 
knots sawed lengthwise and tapering 
toward the pith at a common point.  
corner knot --located at the intersect ion 
of adjacent faces.  
knot cluster --two or more knots grouped 
together as a unit with the fibers of 
the wood deflected around the entire 
unit. A group of single knots is not a 
knot cluster.  
single knot --occurs by itself. The fibers 
of the wood being deflected around it.  
 
loosened grain --a grain separation or loosening 
between springwood and summerwood wit h-
out di splacement.  
very light loosened grain --not over 0.4 
mm (1/64 inch) separation.  
light loosened grain --not over 0.8 mm 
(1/32 inch) separation.  
medium loosened grain --not over 1.6 
mm (1/16 inch) separation.  
heavy loosened grain --not over 3.2 mm 
(1/8 inch) separation.  
very heavy loosened grain --over 3.2 
mm (1/8 inch) separation.  
 lumber --Lumber is defined as a manufactured 
product derived from a log  through sawing or 
planing .   
 machine bite --a depressed cut of the machine 
knives at the end of a piece.  
very light machine bite --not over 0.4 
mm (1/64 inch) deep.  
light machine bite --not over 0.8 mm 
(1/32 inch) deep.  
medium machine bite --not over 1.6 mm 
(1/16 inch) deep.  
heavy machine bite --not over 3.2 mm 
(1/8 inch) deep.  
very heavy machine bite--over 3.2 mm 
(1/8 inch) deep.  
 machine burn--a darkening of the wood due to 
overheating by machine knives or rolls when 
pieces are stopped in the machine.  
 machine go uge--a groove cut by the machine 
below the desired line.  
very light machine gouge --not over 0.4 
mm (1/64 inch) deep.  
light machine gouge --not over 0.8 mm 
(1/32 inch) deep.  
medium machine gouge --not over 1.6 
mm (1/16 inch) deep.  
heavy machine gouge --not over 3.2 mm 
(1/8 inch) deep.  
very heavy machine gouge--over 3.2 
mm (1/8 inch) deep.  
 
machine offset --an abrupt dressing variation in 
the edge surface which usually occurs near 
the end of the piece without reducing the 
width or without changing the plane of the 
wide surface.  
very light machine offset --a variation 
not over 0.4 mm (1/64 inch).  
light machine offset --a variation not 
over 0.8 mm (1/32 inch).  
medium machine offset --a variation 
not over 1.6 mm (1/16 inch).  
heavy machine offset --a variation not 
over 3. 2 mm (1/8 inch).  
very heavy machine offset --a variation 
over 3.2 mm (1/8 inch).  
 
metric units —See B1.  
 mismanufacture --includes all defects or blem-
ishes, produced in manufacturing.  See 
CHIPPED GRAIN, HIT -AND -MISS, HIT -
OR-MISS, LOOSENED GRAIN, MACHINE 
BURN , MACHINE GOUGE, MISMATCHED 
LUMBER, RAISED GRAIN, SKIP, TORN 
GRAIN, and VARIATION IN SAWING.  
 
mismatch --an uneven fit in worked lumber 
when ad joining pieces do not meet tightly at 
all points of contact or when the surfaces of 
adjoining pieces are not in th e same plane.  
slight mismatch --a barely evident trace 
of mis match.  
very light mismatch --not over 0.4 mm 
(1/64 inch).  
 39 light mismatch --not over 0.8 mm (1/32 
inch).  
medium mismatch --not over 1.6 mm 
(1/16 inch).  
heavy mismatch --not over 3.2 mm (1/8 
inch).  
 
mixed grain (MG )--either vertical or flat 
grained pieces or both.  
 
moisture content --the weight of the water in a 
piece of lumber expressed in a percentage of 
the weight of the piece after being over dried.  
 
occasional pieces --not more than 10% of the 
pieces  in a parcel or shipment.  
 partition —a tongue and grooved piece of lu m-
ber with the same pattern run on both sides. 
For use where both sides may be exposed.  
 
pitch --an accumulation of resinous material.  
light pitch --the light but evident pre s-
ence of pitch.  
medium pitch --a somewhat more ev i-
dent presence of pitch than in the light pitch.  
heavy pitch --a very evident accumul a-
tion of pitch showing by its color and 
consi stency.  
massed pitch --a clearly defined accum u-
lation of solid pitch in a body by it self. 
 
pitch  seam --a shake or check which contains 
pitch.  
 
pitch streak --a well -defined accumulation of 
pitch in the wood cells in a streak.  Pitch 
streaks, with equivalent areas being permi s-
sible, are described as follows:  
very small pitch streak —10mm (3/8 
inch) in w idth and 381 mm (15 inch) 
in length.  
small pitch streak --1/12 the width and 
1/6 the length of the piece.  
medium pitch streak --1/6 the width 
and 1/3 the length of the piece.  large pitch streak --not over 1/4 the 
width by 1/2 the length of the sur face. 
very l arge pitch streak --over 1/4 the 
width by 1/2 the length of the sur face. 
 
pith--the small soft core in the structural center 
of a log.  
very small pith --not over 3.2 mm (1/8 
inch) wide and occupies on the face 
surface not over 161 square mm (1/4 square inch)  [3.2 mm by 51 mm (1/8 
inch wide by 2 inch long), or 1.6 mm by 102 mm (1/16 inch by 4 inch)]  
small pith --not over 484 square mm (3/4 
square inch) on the face surface [6 
mm by 76 mm (1/4 inch by 3 inch), 5 
mm by 102 mm (3/16 inch by 4 inch), 
3.2 mm by 152 m m (1/8 inch by 6 
inch), or 1.6 mm by 305 mm (1/16 
inch by 12 inch)]  
free of pith --the prohibition of pith on or 
within the body of the piece.  
boxed pith --pith that is within the four 
faces of an end of a piece.  
 
pocket --a well- defined opening, between the 
rings of annual growth, which develops dur-
ing the growth of the tree. It usually contains pitch or bark. Pockets are described as fol-lows with equivalent areas being permiss i-
ble: 
very small pocket —1.6 mm (1/16 inch) 
in width and 76 mm (3 inch) in 
length, o r 3.2 mm (1/8 inch) in width 
and 51 mm (2 inch) in length.  
small pocket —1.6 mm (1/16 inch) in 
width and 152 mm (6 inch) in length, or 3.2 mm (1/8 inch) in width and 102 mm (4 inch) in length, or 6 mm (1/4 
inch) in width and 51 mm (2 inch) in 
length.  
medium pocket —1.6 mm (1/16 inch) in 
width and 305 mm (12 inch) in length, or 3.2 mm (1/8 inch) in width 
and 203 mm (8 inch) in length, or 10 
mm (3/8 inch) in width and 102 mm (4 inch) in length.  
 40 large pocket --not over 2581 square mm 
(4 square inches) in area.  
very large pocket --over 2581 square 
mm (4 square inches) in area.  
closed pocket --an opening on one sur-
face only.  
open (through) pocket --an opening on 
opposite surfaces. A through opening 
is considered the same as a through 
hole of equal size.  
 
raised grain -a roughened condition of the su r-
face of dressed lumber in which the hard 
summerwood is raised above the softer springwood, but not torn loose from it.  
very light raised grain --not over 0.4 
mm (1/64 inch).  
light raised grain --not over 0.8 mm 
(1/32 inch).  
medium raised grain --not over 1.6 mm 
(1/16 inch).  
heavy raised grain --not over 3.2 mm 
(1/8 inch).  
 
resawn lumber-- the product of sawing any 
thickness of lumber to develop thinner lu m-
ber. 
 
ripped lumber --the product of sawing any 
width of lumber to develop na rrower lumber.  
 
sapwood --the outer layers of growth between 
the bark and heartwood that contain the sap.  
bright sapwood --sapwood that shows no 
stain and is not limited in any grade 
unless specifically stated in the grade description.  
sapwood restrictions w aived--a lifting 
of any restrictions in a rule on the amount of sapwood permitted in piec-es graded under that rule.  
bright sapwood no defect (BSND) --an 
indication that bright sapwood is 
permitted in each piece in any 
amount.  
 
seasoning --evaporation or extr action of mois-
ture from green or partially dried wood.   
shake --a lengthwise separation of the wood 
which occurs between or through the rings of 
annual growth.  
fine shake --a barely perceptible open ing. 
light shake --not over 0.8 mm (1/32 inch) 
wide.  
medium s hake --not over 3.2 mm (1/8 
inch) wide.  
open shake --over 3.2 mm (1/8 inch) 
wide.  
ring shake --occurs between the annual 
rings to partially or wholly encircle 
the pith.  
surface shake --occurs on only one su r-
face of a piece.  
through shake --extends from one su r-
face of a piece to the opposite or to an 
adjoining surface.  
pith shake (heart check or heart 
shake) --extends through the annual 
rings from or through the pith to-wards the surface of a piece, and is distinguished from a seasoning check 
by the fact that its g reatest width is 
nearest the pith, whereas the greatest 
width of a season check in a pith -
centered piece is farthest from the 
pith.  
 
side cut --pith is not enclosed within the four 
sides of the piece.  
 
skip--area on a piece that failed to surface clean. 
Skips are described as follows:  
very light skip --not over 0.4 mm (1/64 
inch) deep.  
light skip --not over 0.8 mm (1/32 inch) 
deep.  
medium skip --not over 1.6 mm (1/16 
inch) deep.  
heavy skip --not over 3.2 mm (1/8 inch) 
deep.  
 
slope of grain --the deviation of the line of fibers 
from a straight line parallel to the sides of 
the piece.  
 
 41 softwood --one of the group of trees which have 
needle- like or scale- like leaves. The term has 
no specific reference to the softness of the 
wood.  
 
sound --free of decay.  
 
spiral grain --a deviation in the slope of grain 
caused when the fibers in a tree take a spiral 
course around the trunk of the tree instead of the normal vertical course.  
 
split --a separation of the wood through the piece 
to the opposite surface or to an adjoining su r-
face due to the tearing apart of the wood 
cells.  
very short split --equal in length to 1/2 
the width of the piece.  
short split --equal in length to the width 
of the piece and in no case exceeds 1/6 
the length.  
medium split --equal in length to twice 
the width of  the piece and in no case 
exceeds 1/6 the length.  
long split --longer than a medium split.  
 
springwood --the portion of the annual ring 
formed during the early part of the yearly 
growth period. It is lighter in color, less 
dense, and not as strong mechanical ly as 
summe rwood.  
 
square corners --without eased edges but has 
an allo wance for wane in certain grades.  
 square edged --free from wane and without 
eased edges.  
 stained wood --a discoloration in wood.  
stained heartwood or firm red heart --
heartwood that shows  a marked var i-
ation from the natural color. In 
grades where it is permitted, stained 
heartwood has no more effect on the 
intended use of a piece than other characteristics permitted in the grade.  Note: Stained heartwood ran g-
es from pink to brown, and is no t to be confused with natural red heart. Nat-
ural color is usually uniformly di s-
tributed through certain annual rings, 
whereas stains are usually in irreg u-
lar patches.  
stained sapwood--sapwood with discol-
oration. In grades when it is permi t-
ted, stained sapw ood has no more ef-
fect on the intended use of a piece 
than other characteristics permitted in the grade but it does affect appea r-
ance in varying d egrees:  
light stained sapwood --a disco l-
oration so slight that it does 
not affect natural fi nishes.  
medium stained sapwood--a 
pronounced difference in color-ing. Note: Sometimes the use-
fulness for natural finishes but 
not for paint finishes is affect-ed. 
heavy stained sapwood--a so 
pronounced di fference in color 
that the grain of the wood is obscured, but lumber cont ain-
ing it is acceptable for paint finishes.  
stained wood resulting from exposure 
to the elements --discolored wood 
that is permitted in all grades of framing and sheathing lumber.  
 stepping -lumber designed to be used for stair 
treads. Customarily surfaced three sides and 
bull-nosed on one edge.  
 
stress grades --lumber having assigned working 
stresses and modulus of elasticity values in 
accordance with accepted basic principles of strength grading, and the provisions of 
6.3.2.1 and 6.3.2.2 of this Standard.  
 
summerwood --the portion of the annual ring 
formed during the latter part of the yearly 
growth. It is darker in color, more dense, and 
stronger mechanically than spring wood.  
 
 42 torn grain --an irregularity in the surface of a 
piece where wood has been torn or b roken 
out by surfacing.  
very light torn grain --not over 0.4 mm 
(1/64 inch) deep.  
light torn grain --not over 0.8 mm (1/32 
inch) deep.  
medium torn grain --not over 1.6 mm 
(1/16 inch) deep.  
heavy torn grain --not over 3.2 mm (1/8 
inch) deep.  
very heavy torn gra in--over 3.2 mm 
(1/8 inch) deep.  
 
trim --to cross -cut a piece to a given length.  
double -end trimmed (DET) --lumber 
trimmed square on both ends. Toler-
ances are found in certified grading rules.  
precision -end trimmed (PET)--lumber 
trimmed square on both ends to un i-
form lengths with a manufacturing tolerance of 1.6 mm (1/16 inch) over 
or under in length in 20% of the piec-
es. 
square -end trimmed --lumber trimmed 
square and having a manufacturing 
tolerance of 0.4 mm (1/64 inch) for 
each nominal 2 inch of thickness or 
width.  
 
unsound  - see DECAY.  
 
variation in sawing --a deviation from the line 
of cut.  
slight variation --not over 1.6 mm (1/16 
inch) scant in nominal 1- inch lumber, 
3.2 mm (1/8 inch) in nominal 2- inch, 5 
mm (3/16 inch) in nominal 3- inch to 7-
inch, and 6 mm (1/4 inch) in nominal 
8-inch and greater thickness or width.  
 
wane --bark or lack of wood from any cause, e x-
cept eased edges, on the edge or corner of a 
piece of lumber.  
 
warp --any deviation from a true or plane sur-
face, i ncluding bow, crook, cup, twist, or any combination thereof. Warp restrictions are 
based on the average form of warp as it oc-
curs normally, and any variation from this 
average form, such as short kinks, shall be 
appraised according to its equivalent effect. Pieces containing two or more forms of warp 
shall be ap praised according to the combined 
effect in determining the amount permiss i-
ble. In grading rules, warp is classified as 
very light, light, medium, and heavy, and applied to each width and length as set forth 
in the various grades i n accordance with the 
following prov isions:  
bow--a deviation flatwise from a straight 
line drawn from end to end of a piece. 
It is measured at the point of greatest 
distance from the straight line.  
crook --a deviation edgewise from a 
straight line drawn from end to end of a piece. It is measured at the point of greatest distance from the straight line. 
cup--a deviation in the face of a piece 
from a straight line drawn from edge to edge of a piece. It is measured at the point of greatest distance from the straight line.  
twist--a deviation flatwise, or a combin a-
tion of flatwise and edgewise, in the form of a curl or spiral, and the amount is the distance an edge of a 
piece at one end is raised above a flat 
surface against which both edges at 
the opposite end a re res ting snugly.  
 
wavy dressing --an involvement of more uneven 
dressing than knife marks.  
very light wavy dressing --not over 0.4 
mm (1/64 inch) deep.  
light wavy dressing --not over 0.8 mm 
(1/32 inch) deep.  
medium wavy dressing --not over 1.6 
mm (1/16 inch)  deep.  
heavy wavy dressing --not over 3.2 mm 
(1/8 inch) deep.  
very heavy wavy dressing --over 3.2 mm 
(1/8 inch) deep.   
 43 APPENDIX C  LUMBER INDUSTRY ABBREVIATIONS  
 
 These abbreviations are commonly used for softwood lumber, although all of them are not 
necessarily applicable to all species. Additional abbreviations which are applicable to a particular region 
or species shall not be used unless included in certified grading rules.  
 
 Abbreviations are commonly used in the forms indicated, but variations such as the use of upper - 
and lower -case type, and the use or omission of periods and other forms of punctuation are not required.  
  AD Air-dried  
 ADF  After deducting freight sides  
 ALS American Softwood Lumber Standard  
 AV or AVG  Average  
 Bd Board  
 Bd ft  Board  foot or feet  
 Bdl Bundle  
 Bev Beveled  
 B/L Bill of lading  
 BM Board Measure  
 Btr Better  
 B&B or B&Btr  B and better  
 B&S  Beams and stringers  
 CB1S  Center bead one side  
 CB2S  Center bead two sides  
 CF Cost and freight  
 CG2E Center groove two edges  
 CIF Cost, insurance, and freight  
 CIFE  Cost, insurance, freight, and exchange  
 Clg Ceiling  
 Clr Clear  
 CM Center matched  
 Com Common  
 CS Caulking seam  
 Csg Casing  
 Cu Ft  Cubic foot or feet  
 CV1S  Center Vee one side  
 CV2S  Center Vee two sides  
 D&H  Dressed and heade d 
 D&M  Dressed and matched  
 DB Clg  Double -beaded ceiling (E&CB1S)  
 DB Part  Double -beaded partition (E&CB2S)  
 DET  Double end trimmed  
 Dim Dimension  
 Dkg Decking  
 D/S or D/Sdg  Drop siding  
 EB1S  Edge bead one side  
 EB2S  Edge bead two sides  
 E&CB1S  Edge and ce nter bead one side  
 44  E&CB2S  Edge and center bead two sides  
 E&CV1S  Edge and center Vee one side  
 E&CV2S  Edge and center Vee two sides  
 EE Eased edges  
 EG Edge (vertical) grain  
 EM End matched  
 EV1S  Edge Vee one side  
 EV2S  Edge Vee two sides  
 Fac Factory  
 FAS Free alongside (named vessel)  
 FBM  Foot or board measure  
 FG Flat (slash) grain  
 Flg Flooring  
 FOB  Free on board (named point)  
 FOHC  Free of heart center or centers  
 FOK  Free of knots  
 Frt Freight  
 Ft Foot or feet  
 GM Grade marked  
 G/R or G/Rfg  Grooved r oofing  
 HB Hollow back  
 H&M  hit-and-miss 
 H or M  hit-or-miss 
 Hrt Heart  
 Hrt CC  Heart cubical content  
 Hrt FA  Heart facial area  
 Hrt G  Heart girth  
 IN Inch or inches  
 J&P Joists and planks  
 KD Kiln-dried  
 Lbr Lumber  
 LCL Less than carload  
 LFT or Lin Ft  Linear foot or feet  
 Lgr Longer  
 Lgth  Length  
 Lin Linear  
 Lng Lining  
 M Thousand  
 MBM  Thousand (feet) board measure  
 MC Moisture content  
 Merch  Merchantable  
 Mldg  Moulding  
 mm Millimeter  
 No Number  
 N1E Nosed one edge  
 N2E Nosed two edges  
 Og Ogee  
 Ord Order  
 Par Paragraph  
 Part Partition  
 45  Pat Pattern  
 Pc Piece 
 Pcs Pieces  
 PE Plain end  
 PO Purchase order  
 P&T Post and timbers  
 Reg Regular  
 Res Resawed or resawn  
 Rfg Roofing  
 Rgh Rough  
 R/L Random lengths  
 R/W Random widths  
 R/W&L  Random widths and lengths  
 Sdg Siding  
 Sel Select  
 S&E  Side and Edge (surfaced on)  
 SE Sdg  Square edge siding  
 SE & S  Square edge and sound  
 S/L or S/LAP Shiplap  
 SL&C  Shipper's load and count  
 SM or Std M  Standard matched  
 Specs  Specifications  
 Std Standard  
 Stpg  Stepping  
 Str or Struc  Structural  
 S1E Surfaced one edge  
 S1S Surfaced one side  
 S1S1E  Surfaced one side and one edge 
 S1S2E  Surfaced one side and two edges  
 S2E Surfaced two edges  
 S2S Surfaced two sides  
 S2S1E  Surfaced two sides and one edge 
 S2S&CM  Surfaced two sides and center matched  
 S2S&SM  Surfaced two sides and standard matched  
 S4S Surfaced four sides  
 S4S&CS Surfaced four sides and caulking seam  
 T&G  Tongued and grooved  
 VG Vertical grain  
 Wdr Wider  
 Wt Weight  
 46 APPENDIX D  IMPLEMENTATION  AND MAINTENANCE OF STANDARD  
 
D1. STANDING COMMITTEE  
 
The American Lumber Standard Committee (ALSC) acts as the Standing Committee for this Standard for the purpose of its interpretation 
and for considering future proposals for 
amendments and revisions. Members of the 
ALSC and their  alternates are appointed by the 
Secretary of Commerce in accordance with Section 9 of this Standard. The names of the 
members are available from the Committee's 
secretariat: Standards Services  Division , 
National Institute of Standards and Technology, 
Gaithersburg, Maryland 20899- 2100. Comments 
regarding the Standard and suggestions for its 
amendment or revision may also be sent to this 
address. No product shall be advertised or 
represented in any manner that would imply approval or endorsement of that product by the National Institute of Standards and Technology 
and/or the Department of Commerce.  
 
D2. EFFECTIVE DATE  
 Voluntary Product Standard PS 20 -15, American 
Softwood Lumber Standard , a voluntary 
standard developed under the Department of Commerce procedures, shall be effective April,  
2015 for products produced thereunder on and 
after that date. The Standard being superseded, 
American Softwood Lumber Standard PS 20 -10, 
is effective for products produced thereunder 
through March , 2015 . 
 
D3. HISTORY OF THE STANDARD  
 
Early in 1922 Secretary of Commerce Herbert 
Hoover, responding to a request from the lumber industry, offered the cooperation of the 
Department in activities directed toward simplification, standardization, and development 
of adequate quality guarantees for the lumber -
consuming public. This cooperation led to the 
development and publication in 1924 of 
Simplified Practice Recommendation R 16 under 
the guidance of the Department's Division of 
Simplified Practices, which was to become a part 
of the National Bureau of Standards (now the National Institute of Standards and 
Technology). The history of R 16's development 
and its subsequent revisions is summarized  in 
editions issued, respectively, in 1924, 1925, 
1926, 1929, 1939, and 1953.  
 
R 16-53 was rev ised in 1969 and superseded by 
Voluntary Product Standard PS 20 -70 American 
Softwood Lumber Standard. The significant 
provisions added to PS 20 -70 were: 1) separate 
size standards for dry and green lumber, under 
nominal 5- inch thickness, were established in 
order to achieve greater uniformity in the 
dimensions of seasoned and unseasoned lumber at the point of use; 2) an independent National Grading Rule Committee was created to 
establish and maintain a national grading rule 
for dimension lumber conforming t o PS 20; 3) an 
independent Board of Review was formed to assure uniform approval of grading rules and of agencies to grade under these rules, and to 
enhance enforcement of the accreditation 
program ; 4) the composition of the American 
Lumber Standard Commi ttee was expanded to 
reflect a broader representation of interests;  and 
5) uniform methods for assignment of design 
values were accepted. Non -substantive changes 
were made to the Standard in 1985, 1991, 1992,  
1999, 2005 and 2010.  The Standard was 
reviewed  in 2014 to assure it reflected the needs 
of manufacturers, distributors and consumers.  
 
D4. CURRENT EDITION  
 
The current edition, PS 20 -15, has the same 
technical requirements and administrative 
structure for implementing and enforcing the 
Standard as its  previous edition. This new 
edition was based on the recommendations 
resulting from an extensive technical and editorial review of PS 20 -10 conducted by the 
Standing Committee with the assistance from 
the National Institute of Standards and 
Technology in 2 014. 
 47 American Softwood 
Lumber StandardVoluntary Product Standard PS 20-15
April 2015
Supersedes Voluntary Product Standard PS 20-10