Voluntary Product Standard PS 20 -1520 
American Sof twood Lumber Standard 
Supersedes Voluntary Product Standard PS 20 -1015 
April 20152020 
U.S. Department of Commerce 
Penny Pritzker , Secretary 
National Institute of Standar ds and T echnology 
Willie E. May , Acting Under Secretary of Commerce for Standards and Technology and Director   
 
 
 
 
 
  
 
 
 
 
 
 
 
 
 
 
 
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 VOLUNTARY PRODUCT STANDARDS 
providing technical or other counsel as appr o-
Development of Voluntary Product priate, promoting the use of and support for the 
Standards standards, and assisting in keeping the stan d-
ards current with respect to advancing techno l-
Voluntary P roduct Standards are developed ogy and marketing practices. 
under pr ocedures published by the Department 
of Commerce in Title 15 Code of Federal Reg u- Use of Voluntary P roduct S tandards 
lations Part 10, Procedures for the Development 
of Voluntary Product Standards . The purpose of The use of Voluntary Product Standards is vo l-
these standards is to establish n ationall y rec- untary. NIST has no regulatory power in the 
ognized requirements for products and provide enforcement of their provisions: however, since 
all concerned interests with a basis for common the standards represent a consensus of all i n-
understanding of the characteristics of the terested groups, their provisions are likely to 
products. The National Institute of Standards become e stablish ed as trade customs. In add i-
and Technology (NIST) administer s the Volu n- tion, when a Voluntary Product Standard is 
tary Product Sta ndards P rogram on a rei m- made a part of a legal document, such as a sales 
bursable basis. contract or code, compliance with the standard 
is enforc eable. 
Role of NIST 
The benefits derived from Voluntary Product 
The role of NIST in the establishment of Volu n- Standards are in dir ect prop ortion to their ge n-
tary Product Standards is to act as an unbiased eral recognition and actual use. Producers and 
coordinator in their development, provide edit o- distributors whose products meet the requir e-
rial assistance in their preparation, supply such ments of a Voluntary Product Standard may r e-
assistance and rev iew as is required to assure fer to the standard in advertising and on labels 
their technical soundness, and to seek satisfa c- to promote greater public understanding for 
tory resolution of valid points of disagre ement. confidenc e in their products. At times, purcha s-
NIST also determines compliance with the cr i- ers may order products conforming to the r e-
teria of the Department’s procedures, provides quirements of a Voluntary Product Standard. 
secretarial functions for each c ommittee ap-
pointed under the procedures, and publishes For copies of the Voluntary Product Standards 
the standards as public documents. procedures or for more information concerning 
the development and use of the se stand ards, 
Producers, distributors, users, consumers, and contact the Standards Services Division , Na-
other interested groups contribute to the esta b- tional Institute of Standards and Technology, 
lishment of Voluntary Product Standards by i n- Gaithersburg, MD 20899 -2100. 
itiating and participating in thei r develo pment, 
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      Voluntary Product Standard 
PS 20 -1520 
(Supersedes Voluntary Produ ct Standar d PS 20 -1015) 
AMERICAN SOFTWOOD LUMBER STANDARD 
PREFACE 
The American Softwood Lumber Standard was d eveloped by the American Lumber 
Standard Committee (ALSC) in accordance with the Procedures 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 i ts 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 ad opts 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 pr o-
gram for manufacturers, distri butors, 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 pr o-
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. 
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 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, th e 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 in spection. 
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 defin ed 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 fun c-
tions of the American Lumber Standard Co m-
mittee, the Board of Review, and the N ational 
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 Standa rd 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 -1520; lumber 
inspection; lumber sizes; mois ture content of 
lumber; National Grading Ru le; softwood l um-
ber standard 
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 TABLE OF CONTENTS 
PREFACE ................................ ................................ ................................ ................................ . 5 
1. SCOPE ................................ ................................ ................................ ................................ . 9 
2. TERMINOLOGY ................................ ................................ ................................ ................ 10 
3. CLASSIF ICATION ................................ ................................ ................................ ............ 11 
4. MEASUREMENT AND TALLY ................................ ................................ .................... 1312 
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 
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  AMERICAN SO FTWOOD LUMBER STANDARD 
Effective April , 20152020 
[This Standard , which was initiated by the American Lumber Standard Committee, has been devel -
oped under the Procedures for the Development of Voluntary Product Standards of the U.S. Depart -
ment of Comme rce to supersede PS 20-10 15 “American Softwood Lumber Sta ndard.”] 
1. SCOPE 
1.1.3 It This Standard establishes the princi -
1.1 General pal trade class ifications and sizes of softwood 
lumber for yard, structural, factory and shop u se. 
1.1.1 This Voluntary Product Standard esta b- It provides for th e classificati on, measurement, 
lishes and maintains, through a consensus pr o- grading and grade marking of rough and dressed 
cess and in the public interest, standard sizes sizes of va rious items of lumber including finish, 
(both in metric1 and conv entional units) and ge n- boards, dimension and timbers. Terms and pro -
eral requirements for developing grades of sof t- cedures are defined and discussed to provide a 
wood lumber . It is implemented through an i n- basis for the use of uniform methods in the grad -
ternationally recognized accreditation and certi- ing, inspection, measurement and description of 
fication program, the purpose of which is to pro- softwood lumber. 
vide for uniform, industry -wide grade marking 
and inspe ction of soft wood lumber. Note: The provisions of this Standard do not a p-
ply to the myriad of products of remanufacture 
1.1.2 This Standard also provides a basis for (for example: turned balusters, peeler cores, etc.) 
the coordination of the grades of the various sp e- or manufa ctured components (for example: trus s-
cies of softwood lumber, the assignment of design es, lattice panels, I -joists, etc.) that use “American 
values to lumber when called for, and the prep a- Lumber Standard” (ALS ) program lumber as a 
ration of grading rules appl icable to each species . raw material. 
The provisions of this Standard apply to stru c-
tural lumber manufactured from hardwood sp e- 1.1.4 This Standard applies to lumber that is 
cies or lumber manufactured from foreign species to be ide ntified as a manufactured product from 
when the species is included in rules certified by a softwood l og in a sawmill, or in a sawmill and 
the Board of Review. It is not intended to be used planing mill. Such lumber, when rough, shall 
either as grad ing rules or as purchase specific a- show saw or other primary manufa cturing marks 
tions. Italicized notes in this Standard are no n- in the wood on the four longitudinal surfaces of 
mandatory. each piece for its over -all length and shall not 
have been further manufactured other than by 
crosscu tting, ripping , resawing, joining by fin- 1 Metric units are provided initially follow ed by conventio n-
al units. gerjointing, face -gluing and/or edge -gluing , sur-
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   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 “Americ an 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 abbre vi-
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 s pecific 
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 
nomi nal width in feet by t he length in f eet. For 
metric measur ement, [see 2.5] 
2 The American Lumber St andard Commi ttee, Inc., its 
Board of Review, and its National Grading Rule Co m-
mittee disclaim any liability for damages, includi ng 
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 r e-
quirements. 
2.4 Characteristics --Distinguishing fea-
tures which by the ir 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 e x-
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 multipl y-
ing the dressed thickness in millimeters by the 
dressed width in millimete rs 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 . Strength and sti ffness property val -
ues of structural lumber products published for 
design use . These values are de termined for spe-
cific grades and species/species groups and re -
flect the fact that wood is an orthotropic materi -
al. 
2.7 Dry lumber --Lumber of less than nom i-
nal 5 -inch thi ckness which has been seas oned or 
dried to a maximum moisture content of 19 pe r-
cent. 
Note: Lumber of nominal 5 -inch or greater thic k-
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 
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 lumber as having a maximum moisture content 
higher than 19 percen t.[see 6. 2.6] 
2.8 Grade marked (g rade stamped) --
Lumber that displays the official grading mark of 
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 grad ing agenc y and is appl ied 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) t he agency 
symbol; 3) the species or combination of species of 
the lumber; 4) whether the lumber was dry or 
green when manufactured (but, see 6.2.6) ; and 5) 
the a ppropriate grade. Where required by the 
grading rules, grade marks shall also denote rule 
parag raph s under w hich the lumber was graded 
or other similar i nform ation. 
2.9 Grade – A minimum standard s pecifying 
the permitted characteristics of lumber, having 
regard to the end use for which the lumber is in-
tended . 
2.109 Grading ag ency --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. 
2.110 Grading rules --Requirements and spe c-
ificati ons for the manufactur e, inspection and 
grading of desi gnated 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. 
2.121 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 g rading rules ce r-
tified by the Board . 
2.132 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 m inutes. 
2.143 Kiln dr ied (KD) --Lum ber that has been 
seasoned in a chamber to a predetermined moi s-
ture content by appl ying heat. 
2.154 Lumber --Lumber is defined as a man u-
factured product derived from a log through sa w-
ing or planing . [see 3.3] 
2.15 Lumbe r grades --Manufacturin g 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 greate r than the 
dressed size i.e ., a dry “2 by 4 ” is surfaced to 38 .1 
mm by 8 8.99 mm (1 1/2 by 3 1/2 inches) [see 
3.4.4] . 
2.17 Species --The commercial names co n-
tained in Appendix A for lumber cut from the 
principal botanical species of s oftwood shall be 
used in th e formulation of lumber 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 Genera l—ALS program lumber shall be 
classified according to the use, extent -of-
manufacture and nominal size. 
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          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] 
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-manufact ure 
3.3.1 Rough lumber --Lumber which ha s 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 t he 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 o ne or more fa ces. When sized lumber is 
grade marked it shall be l abeled 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 (S 1S), two sides (S2S), one e dge (S1E), 
two edges (S2E), or a combination of sides and 
edges (S1S1E, S1S2E, S2S1E, S4S). Lumber su r-
faced S1E, S2E, S1S, S2S, S1S1E, S1S2E, S2S1E, S4S is classified as dressed (surfaced) lumber in 
the su rfaced width or thicknes s. 
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 clo se tongue -and-
groove joint by fitting tw o 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 o f each piece to provide 
a close -lapped joint by fitting two pieces together. 
3.3.3.3 Patterned lum ber--Lumber shaped to 
a pattern 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 th ickness 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 o r greater wid th. 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, s ills, 
girders, or purlins. 
3.4.4 The dr essed sizes of all lumber dime n-
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 
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 Standard follows the practice of the industry. No 
inferences sha ll be drawn t hat 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. 
Note: The i nvoices 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 nonstandar d sizes shall be tallied board 
measure a s 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 th ickness 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 foo t 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 Averages3--length, width --The average 
length in feet of a shipme nt of lumber is computed 
by dividing the total length in fe et by the total 
number of p ieces 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 divi d-
ing the total board feet by the total l ength in feet 
and multiplying the results by 12; but if the pieces 
are thicker than no minal 1 inch, the total board 
3 This computation applies to c onventional units. 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 m ore inches 
in nominal thick ness shall be not less than 3.2 
mm (1/8 inch) thicker than the corresponding 
minimum dressed thickness, except that up to 20 
percent of a shipment shall be not less than 2.4 
mm (3/32 inch) thicker than the corresponding 
minimum d ressed thickness. The minim um 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 thos e items as measured at time of 
manufacture. Lumber will change in dimension 
(shrink or expand) in response to its equili brium 
moisture content. [see 6.2.3.1 and 6.2.5.1] [see a l-
so 5.3.1 covering length and 7.3 for gr ade mar king 
nonstandard siz es.] 
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 o f 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 nomin al 
length. Th e 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). 
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      Note: The marketin g practice covering lengths of lengths or specif ied assortments of lengths. 
lumber should permit the buy er to obtain specified 
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 thickne sses except a s 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 
3/8 8 5/16 2 38 1-1/2 
1/2 11 7/16 3 64 2-1/2 
5/8 14 9/16 4 89 3-1/2 
3/4 16 5/8 5 114 4-1/2 
1 19 3/4 6 140 5-1/2 
1-1/4 25 1 7 165 6-1/2 
Finish 1-1/2 32 1-1/4 8 184 7-1/4 
1-3/4 35 1-3/8 9 210 8-1/4 
2 38 1-1/2 10 235 9-1/4 
2-1/2 51 2 11 260 10-1/4 
3 64 2-1/2 12 286 11-1/4 
3-1/2 76 3 14 337 13-1/4 
4 89 3-1/2 16 387 15-1/4 
3/8 8 5/16 2 29 1-1/8 
1/2 11 7/16 3 54 2-1/8 
Flooring a 5/8 14 9/16 4 79 3-1/8 
1 19 3/4 5 105 4-1/8 
1-1/4 25 1 6 130 5-1/8 
1-1/2 32 1-1/4 
3/8 8 5/16 3 54 2-1/8 
Ceiling a 1/2 11 7/16 4 79 3-1/8 
5/8 14 9/16 5 105 4-1/8 
3/4 17 11/16 6 130 5-1/8 
3 54 2-1/8 
4 79 3-1/8Partition a 1 18 23/32 5 105 4-1/8 
6 130 5-1/8 
Stepping 1 19 3/4 8 184 7-1/4 
1-1/4 25 1 10 235 9-1/4 
1-1/2 32 1-1/4 12 286 11-1/4 
2 38 1-1/2 
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 fac e widths sho wn 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 lumbe r, and the lap shall be 10 m m (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 ma ximum -
moistu re conte nt. 
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 metr ic units. 
Item Thicknesse s Widths 
Nominal 
Inch Minimum Dressed Nominal 
Inch Minimum Dressed 
mm Inch mm inch 
1/2 11 butt, 5 tip 7/16 butt, 3/16 tip 4 89 3-1/2 
9/16 12 butt, 5 tip 15/32 butt , 3/16 tip 5 114 4-1/2 
Plain Bevel 5/8 14 butt, 5 tip 9/16 butt, 3/16 tip 6 140 5-1/2 
3/4 17 butt, 5 tip 11/16 b utt, 3 /16 tip 8 184 7-1/4 
1 19 butt, 5 tip 3/4 butt, 3/16 tip 10 235 9-1/4 
12 286 11-1/4 
4 89 3-1/2 
6 140 5-1/2 
Rabbeted 1/2 11 butt, 5 tip 7/16 butt, 3/16 tip 
Bevel 3/4 17 butt, 7 t ip 11/16 butt, 9/32 tip 8 184 7-1/4 
10 235 9-1/4 
12 286 11-1/4 
6 140 5-1/2 
Bungalow 3/4 17 butt, 5 tip 11/16 butt, 3/16 tip 8 184 7-1/4 
10 235 9-1/4 
12 286 11-1/4 
4 76 3 
5 102 4 
Shiplap (10 5/8 14 9/16 6 127 5 
mm (3/8 in.) 
lap)b 1 18 a 23/32 a 8 171 6-3/4 
10 222 8-3/4 
12 273 10-3/4 
4 73 2-7/8 
Shiplap ( 13 5/8 14 9/16 5 98 3-7/8 
mm (1/2 in.) 1 18 a 23/32 a 6 124 4-7/8 
lap)b 2 38 1-1/2 8 168 6-5/8 
10 219 8-5/8 
12 270 10-5/8 
Dressed and 4 79 3-1/8 
Matched 5 105 4-1/8 
(Tongue and 5/8 14 9/16 6 130 5-1/8 
Grooved, 6 1 18 a 23/32 a 8 175 6-7/8 
mm (1/4 in.) 10 225 8-7/8 
tongue)b 12 276 10-7/8 
Dressed and 4 76 3 
Matched 6 127 5 
(Tongue and 1 18 a 23/32 a 8 171 6-3/4Grooved, 10 
mm (3/8 in.) 10 222 8-3/4 
tongue)b 12 273 10-3/4 
a Minimum dressed thickness for 1 -inch nom inal redwood and western r ed cedar shi plap a nd 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 th e 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. 
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          Table 3. Nominal and minimum -dressed sizes of boards, dimension, a nd 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 metr ic units. 
Item Thicknesse s Widths 
Nominal 
Inch Minimum Dressed Nominal 
Inch Minimum Dres sed 
Dry a Green a Dry a Green a 
mm inch mm Inch mm inch mm inch 
2 38 1-1/2 40 1-9/16 
3 64 2-1/2 65 2-9/16 
4 89 3-1/2 90 3-9/16 
3/8 8 5/16 9 11/32 5 114 4-1/2 117 4-5/8 
1/2 11 7/16 12 15/32 6 140 5-1/2 143 5-5/8 
5/8 14 9/16 15 19/32 7 165 6-1/2 168 6-5/8 
Boards 3/4 16 5/8 17 11/16 8 184 7-1/4 190 7-1/2 
1 19 3/4 20 25/32 9 210 8-1/4 216 8-1/2 
1-1/4 25 1 26 1-1/32 10 235 9-1/4 241 9-1/2 
1-1/2 32 1-1/4 33 1-9/32 11 260 10-1/4 267 10-1/2 
12 286 11-1/4 292 11-1/2 
14 337 13-1/4 343 13-1/2 
16 387 15-1/4 394 15-1/2 
2 38 1-1/2 40 1-9/16 
2 1/2 51 2 52 2-1/16 
3 64 2-1/2 65 2-9/16 
2 38 1-1/2 40 1-9/16 3 1/2 76 3 78 3-1/16 
2-1/2 51 2 52 2-1/16 4 89 3-1/2 90 3-9/16 
3 64 2-1/2 65 2-9/16 4 1/2 102 4 103 4-1/16 
Dimension 3-1/2 76 3 78 3-1/16 5 114 4-1/2 117 4-5/8 
4 89 3-1/2 90 3-9/16 6 140 5-1/2 143 5-5/8 
4-1/2 102 4 103 4-1/16 8 184 7-1/4 190 7-1/2 
10 235 9-1/4 241 9-1/2 
12 286 11-1/4 292 11-1/2 
14 337 13-1/4 343 13-1/2 
16 387 15-1/4 394 15-1/2 
Timbe rs 5 & 6 
thick 13 off 1/2 off 13 off 1/2 off 5 & 6 
wide 13 of f 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 2.1 1 for the definitions of dry and green lumber. 
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 Table 4. Nominal and minimum -dressed sizes of wo rked lumber. 
The thicknesses apply to all widths and all widt hs apply to all thicknesses. Sizes are given in millimeters and inches. 
Metric units a re 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 
4 79 3-1/8 81 3-3/16 
6 130 5-1/8 133 5-1/4 
Shiplap, 8 175 6-7/8 181 7-1/8 
10 mm (3/8 inch) 1 19d 3/4d 20 25/32 10 225 8-7/8 232 9-1/8 
lapb 12 276 10-7/8 283 11-1/8 
14 327 12-7/8 333 13-1/8 
16 378 14-7/8 384 15-1/8 
1 19d 3/4d 20 25/32 4 76 3 78 3-1/16 
2 38 1-1/2 40 1-9/16 6 127 5 130 5-1/8 
Shiplap, 2-1/2 51 2 52 2-1/16 8 171 6-3/4 178 7 
13 mm (1/2 inch) 3 64 2-1/2 65 2-9/16 10 222 8-3/4 229 9 
lap b,c 3-1/2 76 3 78 3-1/16 12 273 10-3/4 279 11 
4 89 3-1/2 90 3-9/16 14 324 12-3/4 330 13 
4-1/2 102 4 103 4-1/16 16 375 14-3/4 381 15 
Cent ermatch 4 79 3-1/8 81 3-3/16 
(Ton gue & 1 19d 3/4d 20 25/32 5 105 4-1/8 108 4-1/4 
6 130 5-1/8 133 5-1/4Groove), 1-1/4 25 1 26 1-1/32 8 175 6-7/8 181 7-1/86 mm (1/4 inch) 1-1/2 32 1-1/4 33 1-9/32 
tongueb 10 225 8-7/8 232 9-1/8 
12 276 10-7/8 283 11-1/8 
Centermatch 2 38 1-1/2 40 1-9/16 4 76 3 78 3-1/16 
(Tongue & 2-1/2 51 2 52 2-1/16 6 127 5 130 5-1/8 
Groove), 3 64 2-1/2 65 2-9/16 8 171 6-3/4 178 7 
10 mm (3/8 inch) 3-1/2 76 3 78 3-1/16 10 222 8-3/4 229 9 
tongue c 4 89 3-1/2 90 3-9/16 12 273 10-3/4 279 11 
4-1/2 102 4 103 4-1/16 
2-1/2 51 2 52 2-1/16 4 89 3-1/2 90 3-9/16 
Grooved -for-3 64 2-1/2 65 2-9/16 6 140 5-1/2 143 5-5/8 
Splines 3-1/2 76 3 78 3-1/16 8 184 7-1/4 190 7-1/2 
4 89 3-1/2 90 3-9/16 10 235 9-1/4 241 9-1/2 
4-1/2 102 4 103 4-1/16 12 286 11-1/4 292 11-1/2 
a See 2.7 and 2.11 for the definitions of dry and green lumber. 
b In worked lumber less than no minal 2 -inch thickness, the tongue shall be 6 mm (1/4 inch) wide i n tongued and grooved lumber and 
the lap shall be 10 mm (3/8 inch) or 13 mm (1/2 inch) wide in shi plapped lumber, with the over -all widths 6 mm (1/4 inch), 10 
mm (3/8 inch) and 13 mm (1/2 in ch) wider, respectively, than the face widths shown in the above t able. 
cIn worked lumber of nominal 2 -inch and greater thick ness, the tongue shall be 10 mm (3/8 i nch) wide in tongued -and-grooved lu m-
ber and the lap shall be 13 mm (1/2 inch) wide in shipla pped 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 tongu e. 
d Alternate minimum dressed dry thickness for 1 -inch nominal center -match and shiplap is 18 mm (23/32 inch). 
17        
 
   
 
      
       
         
          
        
        
         
         
          
       
      
      
        
      
         
       
       
 
 
    
       
       
         
         
       
     
         
       
          
      
        
 
    
       
         
         
        
       
        
        
     
                
        
         
       
       
 
         
          
            
 
    
      
      
        
          
     
 
     
       
         
  
 
   
        
       
        
         
     
 
   
 
     
      
      
        
        
          
       
       
        
       
     
       
       
       
      6. GRADI NG RULE REQUIREMENTS 
6.1 General conc epts 
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 ba sic provisions for the gra ding of 
lumb er 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 mechanica lly determining the 
streng th character istics 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 th at a grade 
qualifies under two use cla ssifications, the grade 
provisions shall satisfy the r equirements for both 
classifications. 
6.1.2 Minimum grade requirements --The 
method o f determining the e xtent and limitations 
of the characteristics permitted in th e poorest 
pieces admissibl e in each gr ade of lumber shall be 
stated in a certified rule, except in the lowest 
grade of each classification. Since lumber grades 
are broad manufac turing categories, grades ove r-
lap and pieces are selected from a grade to co m-
prise another grade outside of that grad e 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 t he grade. 
6.1.3 Grade ch aracteristics -Characteristics 
permi tted and limitations for rough lumber shall 
be the same as tho se prescribed in grading rules 
for dressed lumber of the same grade and, in add i-
tion, such others as will disappear in standard 
dressing sh all be allowed. If chara cteristics other 
than those described in certified grad ing rules are 
encountered, they shall be evaluated in relation to 
the characteristics permitted or limitations pr e-
scribed for the grade under consideration and shall be allowed if regarded as equi valent or less 
damaging in effect on the strength, appearanc e, 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 gra des, the size of pe rmitted cha r-
acteri stics varies in proportion to the size of a face 
or the area of a cr oss 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 desig nated, 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 ru le category shall n ot be included in certified 
grading rules. 
6.1.6 Nonstandar d grades --When nonstan d-
ard grades, siz es, or patterns are specified, or 
when particular provisions of a standard grade 
are waived or changed, inspection shall be made 
accordingl y, but all of the o ther provisions of the 
certified grading rules shall apply. 
6.2 Seasoning provisions 
6.2.1 Gener al—The grading rules shall i n-
clude prov isions regulating lumber seasoning and 
moisture content. The provisions shall be deve l-
oped by each g eographical region for each species 
based on its own conditions and the require ments 
of the users of its products sub ject to the other 
provisions of Section 6. Provisions shall be e x-
pressed in terms of maximum moisture content 
allowed in each piece of lumb er and determined i n 
accordance with ASTM D 4444 Standard Test 
Method for Labor atory Standardization and Cali-
bration of Hand -Held Moisture Meters and ASTM 
D 7438 Standard Practice for Field Calibration 
and Application of Hand -Held Moisture Meters as 
approp riate . The restrict ions on the moisture co n-
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  tent of seasoned lumber shall apply at the time of 
shipment, a t the time o f dressing (if dressed lu m-
ber is involved), and at the time of any reinspe c-
tion (if moisture content is involved in the rei n-
spection), as p rovided in the appl icable grading 
rules. Any piece exceeding the allowable moi sture 
content of the appli cable grade provisions shall be 
considered out of compliance. 
6.2.2 Grading rules --The grading rules for 
each species or region shall include clear de fini-
tions for dry l umber under nominal 5 -inch thic k-
ness [see 2.7]. The definiti ons shall be based on a 
maximum moistu re 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 condition s [see 
2.7, 2.11, and 2.1 3]. 
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 conte nt at the time of d ressing, and to be 
not less than ALS minimum dry dressed thi ck-
ness and width at 19 per cent moistur e 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 si zes are shown in 
tables 1, 2, 3 and 4. 
6.2.3.1 Shrinkage or expansion from dr y 
size – Shrinkage or expa nsion that o ccurs after 
dressing to standard dry size shall be recognized 
through the allowance of a tolerance below or 
above minimum standard dry size s on a basis of 
1 percent shrinkage or expansion for each four 
percentage point s of moisture content chan ge 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 ex-pansion of individual pi eces may var y.4 Shrin k-
age allowances are determined assuming max i-
mum allowable moisture content at the time of 
surfa cing. Expansion allowances are dete rmined 
assuming a t ypical equilibrium moisture content 
or other suitable refere nce moisture content. 
6.2.4 Size diff erentials --When the grading 
rules in any region permit lumber less than nom i-
nal 5 -inch thickness to be dressed green, the rules 
shall requi re that the lumber be dressed to sizes 
specifically stated a ccording to both th ickness and 
width, as set forth in t ables 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 gr een sizes5 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 nomin al 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 orien tation and allowable grade chara c-
teristics. See Forest Produ cts 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 ma nu-
facturing practices and the differences in shrinkage 
characteristics between species of lumber or species 
groups o f lumber. 
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 187 mm (7 -3/8 inch), 238 mm (9 -3/8 inch), 289 mm 
(11-3/8 inch) f or 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 – Shrin kage that occurs af ter dressing to 
standard green size shall be recognized thro ugh 
the allowance of a tol erance 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, 
West ern Red Ceda r, and Northern White Cedar. 
Expansion allowances are dete rmined assuming 
a typical equilibrium moisture content or other 
suitable referenc e moisture content. The shrin k-
age or expansion percentages are average values. 
Shrinkage or expansion of individual p ieces may 
vary.6 
6.2.6 Grade marking (grade stamping) --
Grading rules that provide for grade marking of 
lumber less than nominal 5 -inch thi ckness shall 
contai n a provision for standardized marking so 
as to indicate whe ther the lumber was green or 
dry at ti me 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 co ntent of 19 percent at time of surfacing. 
Moisture -content limits of less than 19 percent 
maximum moistur e-content fo r 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 cer tified 
by the Board. 
6 The range of shri nkage of individual pieces from exper i-
mental obse rvation is from 2% to 7%. Variables that a f-
fect m easurement a nd shrinkage of lumber are: density, 
species, grain orientation and allowable grade chara c-
teristics. See Forest Pro ducts Laboratory Research R e-
ports 15 and 30. 6.3 Use classifi cation provisions for vi s-
ual gra ding 
6.3.1 Yard lumber 
6.3.1.1 Grade classifications --The grading of 
surfaced yard lumber is based upon t he 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) Select: Lumber for natural and paint fi n-
ishes. 
(b) Common: Lumber for general constr uc-
tion and u tility 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 corr esponding nominal sizes as 
shown. 
Note: Lumb er 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 bu n-
dled lumber, except end -matched lumber, beveled 
siding, and bunga low siding shall be bundle d sep-
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 greate r than the nominal inch-unit thic k-
ness, such as are produced by uneven sawing, 
shall, at the option of th e 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] shal l be gra d-
ed from th e face or best side only unless ot herwise 
specified. 
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        6.3.1.6 Fencin g – Sawn boards used in th e 
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 e x-
ceed 1.6 mm (1/16 inch) over o r 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 couns el of the U.S. Forest 
Prod ucts Laborat ory, 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 rule s and, in the 
case of each set of grad ing rules submitted for ce r-
tification, the Board shall obtain a report from the 
Laboratory evaluating whether the procedures 
used in develo ping the claimed va lues are in a c-
cordance with the standards and criteria d e-
scribed herein. Rules -writing agencies sh all make 
available upon request an explanation of the 
means by which the claimed values were d erived. 
When more than one rules -writing agen cy has r e-
sponsibili ty for writing grading rules for a given 
species, a group of species, or a geographica l sub-
divisio n 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 spec ies, 
subdivision, o r 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 a ll such grading 
equipment and methods shall be subject to a p-
proval and certific ation by the Board. 
6.3.2 .3 Grading f aces --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 c lassi-
fications of f actory and shop lumber shall be those 
promu lgated by the age ncies which formulate and 
publish grad ing 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 referenc e to its 
use for do ors and sashes, or on the basis of chara c-
teristics affecting its use for general cutup pur-
poses, o r 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 fr om the poor face based 
on the qua lity 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 cer ti-
fied by the Board. 
6.3.3.4 Warped l umber --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 Agen cy procedures --Each accred ited 
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 inspe c-
tion service under which each mill authorized to 
use the registered symbol of the accre dited age n-
cy7 in conjunction with the grade mark will be i n-
7 Facsimiles of the grade marks o f the grading and inspe c-
tion agencies that are acc redited by t he Board of the 
ALSC, Incorporated, are available on the web at 
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      spected regularly as to grading efficiency and co n-
formity to all the agency esta blished rules for 
grade marking. 
7.3 The Grade mark (grade stamp) --
When ALS pr ogram lumber is grade mark ed, 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 
provisio ns 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 i n Tables 1 -4 or 
below the minimum size s 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 wheth er the lumber was d ry or green when 
dressed. 
7.3.2 A distinguishable mark or i nsignia, re g-
istered and sy mbolizing gr ading 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 t o 
specifiers, purchasers a nd 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 strip s 
bound by some met hod, such as shrink wrap, 
string or similar binding, so as t o form a small 
package. 
www.alsc.org or from the ALSC, I ncorporated, P.O. Box 
210, Germantown, MD 20875 -0210. Telepho ne (301) 
972-1700, Fax (301) 540 -8004. 
8 Ibid. 7.3.3.1 Excep t 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 gr ades, other than th e two highest 
recognized grades for each grading rule catego ry, 
shall not be grade mar ked with a c ombination 
grade designation. 
7.3.5 The grade mark for lumber shall include 
an ident ification or designation of the commercial 
name of th e species [see Appe ndix A] from which 
the lumber was produced. The identificati on of 
species shall not be required wh en 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 o b-
served. 
7.3.7 Remanu facture ( 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 orig inal pro duct and th e original grade 
mark shall be removed, by any appropriate 
means. 
7.3.7.1 When grade marked dimen sion 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 mar k shall be oblitera t-
ed. 
8. INSPECTION AND REINSPECTION 
8.1 Inspection 
8.1.1 Agency certification and superv i-
sion--When ALS program lumber is grade 
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     marked, the grade marking shall be under the d i-
rection, including regular gra ding supervision at 
mills, o f an agency accredi ted by the Board as b e-
ing competent and having adequate faci lities for 
such s upervisio n. 
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 supe rvisory service to those mills which have 
demonstrated and proven their ability to conform 
to and are cur rently in co nformance with the 
grading rules for the species and grades which 
they manufacture. The mill shall also agree to 
maintain the established s tandards of size an d 
grade and to submit its lumber to inspection by 
the superv isory agency both at the m ill 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 reque sting the certifica te shall 
pay for the cost thereof. 
8.1.4 Service --Inspectio n service shall be r e-
quire d for the in spection of grades not described 
in the rules only when written detailed specific a-
tions accompany the r equest for such inspection. 
For the inspection of stand ard grades in no n-
standard sizes, inspection service shall be re-
quired based on 6.1.6 u nless otherw ise 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 se ller 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 lu m-
ber was graded [see 8. 2.4]. Grading rules shall i n-
clude provisions for reinspectio n in case of co m-
plaint, an d reinspecti on shall be available to an y-
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, w orking, or through kiln -
drying shall r elieve the seller of responsibility for 
any grade complaints. 
8.2.3 Buyer's responsibilities --In case of a 
complaint, the buyer shall acce pt that portion of 
the shipment that is of the grade, size, and moi s-
ture conten t 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 s hipment 
that is of the grade, size, and moisture content 
specified shall not be construed as the acceptan ce 
of the en tire 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 sell er within the time specifi ed 
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 co ntent. 
8.2.4 Seller's responsibilities --Upon receipt 
of a co mplaint from the purchaser, the seller shall 
immediately reques t the agency under whose 
rules shipment has been made, or such other 
agency tha t was agreed upon, to prov ide 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 th e inspection provisions 
of the applicable grading rules, but the person 
calling for the reinspection shall be responsible to 
the agency for the costs t hereof. The purchas er 
shall lend all reasonable assistance to facilitate 
the in spection, rei nspection or retally. 
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      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 regard ing grade or size, but not involving 
tally, the buyer shall hold intact that portion o f 
the item t hat 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 o f 
the shipment. 
8.2.7 Moisture content complaints --In case 
of a complaint invo lving moisture content, th e 
buyer shal l 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 o n moisture co n-
tent shall b e made in ac cordance 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 e xceeding such maxim um. 
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 und er which the lumber was graded and 
sold, 95 percent or more thereof is found to be of 
said grade or bette r. When degr ades 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 grad e lower than the gr ade invoice, 
such degrades shall be kept separate and shall be 
the property of the sel ler unless o therwise agreed. 
These provisions shall not apply in the case of 
specially worked lumber. 
9. AMERICAN LUMBER STANDARD 
COMMITTEE 
9.1 Func tions of ALSC --The functions of 
the ALSC shall be: 9.1.1 To act as the Standing Comm ittee for the 
purpose of c onsidering p roposals 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 
appli cable. The Department of C ommerce shal l 
provide the secretariat and appoint a chairman 
for the Standing Committee. 
9.1.2 To cooperate with the U.S. Department 
of Commerce in es tablishing and maki ng contin u-
ously available basic standards for lumber size, 
pattern, quality, inspectio n, and reins pection 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, a nd adequ a-
cy of the facilities provided by agencies pu blishing 
grading rules for the purpose of lumber certific a-
tion, inspection, reinspection, and supe rvision of 
grade ma rking. 
9.1.3.3 The competency, reliability, and adequ a-
cy of the facilities provided b y 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 
interpr etation or application of this Standard and 
the detailed requirements defined and established 
by the ALSC. 
9.1.5 To fix , after consultation with the age n-
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 functi ons, those o f the Board, and the NGRC. 
Such charges and fees shall be assessed at a un i-
form proportionate rate against the agencies pa r-
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       ticipating in th e use of the facili ties of the ALSC . 
The accreditation of any agency not paying its as-
sessment within 60 days after n otification by the 
Secretary of the ALSC shall be revoked by the 
Board. 
9.2 Appointment of members -The pri n-
cipal and alternate members s hall be appointed 
by the Secretary of Commerce for terms of not less 
than two n or more than five years. 
9.3 Composit ion 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-
ipate s in this program a nd that formulates, pu b-
lishes, and maintains grading rules a nd mai n-
tains inspection fa cilities cov ering 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 fu rnished by each agency as follows: 
Agency Members 
Allotted 
Southern Pine Inspection Bureau 2 
Western Wood Products Association 2 
Pacific Lumber Inspection Bureau West Coast 
Lum ber Inspection Bureau 
2 
Redwood Inspection Service 1 
Northeastern Lumber Manuf acturers 
Association 21 
Northern Softwo od 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 rul es. Each non -rules writing 
agency may n ominate a principal and alternate 
member. Three principal members and their a l-ternates shall be appointed from among the no m-
inees so furnis hed. 
9.3.3 Firms or organizations within lumber 
specifying, distributing, and consuming groups, at 
the r equest of th e Secretary of Commerce, may 
nominate a principal and an alternate for each 
member allotted. Principal members and their a l-
ternates shall b e appointed from those groups as 
follows: 
Groups Members 
Allotted 
Lumber D istributors & Wholesalers 2 
Lumber Reta ilers 2 
Wood Using Industries 2 
General Contractors 1 
Home Builders 1 
Architects 1 
Engineers 1 
Wood Treating Industry 1 
9.3.4 The Secretar y of Commerce may appoint 
consumer -at-large principa l members and their 
altern ates to represent the gener al public. 
9.3.5 Each nomination shall be submitted to 
the Secretary of Commerce by the appropriate 
agency, firm, or organization upon request or 
when ever a vacancy occurs in the segment repr e-
sented. Ea ch nomination shall contai n 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 und er which the nominee will exercise the 
responsibilit y of membership for the ag ency or i n-
dustry segment re presented. 
9.3.5.3 A statement of any interests, financial or 
otherwise, which the nominee has in agencies or 
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  segments of the industry other than the one the 
nominee represents. 
9.3.5.4 For agencies s ubmitting more than one 
nominee, a listing in the ord er of priori ty for a p-
pointment. 
9.3.6 Ex officio, non -voting principal and a l-
ternate members may be appointed by the Secr e-
tary of Commerce from the followin g Federal 
agencies: 
Department of Defense 
Departm ent of Agriculture 
Depart ment of Interior 
General S ervices Admi nistration 
Department of Housing & Urban Develo pment 
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 consti tution of the ALSC 
or makin g 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 de termined. 
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, sh all serve 
as the Secretary of the ALSC. 
9.5 Transac tion of business 
9.5.1 Meetings --A majority of the m embers of 
the ALSC representing agencies which formulate, 
publish, and maintain grading rules and maintain 
inspection facilities, together with a major ity of 
the other members, shall constitute a quorum for 
the transaction of bus iness. A vote of the majori ty 
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 meeting or act on the subjects before it, subject to 
ratification in w riting by the respective m ajorities 
which constitute a qu orum. 
9.5.2 Correspondence --Business that has 
not been previously presented at a meeting of the 
ALSC shall be held until the next mee ting or 
transacted by corr espondence in accordance wi th 
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, electi on, terms, co m-
pensation, an d 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 memb er of an accredited 
agency. 
10.2.1 The chairman of the ALSC shall appoint 
a spokesperson for each of the three membe rship 
groups within the ALSC that shall each nominate 
one potential member of the Board. The spoke s-
person shall determine and report the de cision 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 inte rests. 
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 10.2.1.4 The name of the nominee shall be su b-
mitted to the Department of Commerce prior to 
election and shall be accomp anied by a summary 
of the qualifications of the nomi nee and an atte s-
tation that the requirements of 10.2 and 10.2.1 
have been met. 
10.2.2 Election --Board me mbers shall be elec t-
ed by the members of the ALSC by a majority of 
those voting. In the event that a nominee desi g-
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, r espectively, of three 
years, two years, and one year , or until their su c-
cessor s are duly elected. Annuall y 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, re signation, or r e-
moval shall be filled at any regular ly called co m-
mittee meetin g 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 sh all fix and 
pay compensation to the members of the B oard 
and shall reimburse t hem for all reasonable e x-
penses incurre d 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 s hall select 
and e mploy a salaried manager or other executive 
officer, subject to the approval of the ALSC, who 
shall assume the responsibilities and pe rform the 
duties delegated by the ALSC or the Board. Such 
manager or executive officer shall not be in th e employment of any lumber organization, comp a-
ny, or inspection agency while employed by the 
Board. 
10.4 Certification functions --Upon applic a-
tion, th e Board shall examine and certify the fo l-
lowing as c onforming to the requireme nts of this 
Standard and to additional detailed requirements 
established by the ALSC: Grade strength ratios, 
nomenclature, descriptions of grades published by 
the NGRC and gradin g rules published by accre d-
ited, competent and relia ble agencies having ad e-
quate facilities for mill insp ection and f or rei n-
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 se rvice applicable thereto 
are adequate and already fu lly and fairly avail a-
ble to all manufacturers, distri butors, and con-
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 refe rences 
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, a nd consumers of lumber 
on equal terms and conditions and without di s-
criminatio n. 
10.4.4 Subsequent revis ions 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 su bmission to the Board. 
10.4.5 Grading rules of an agency shall not be 
certified as conforming to this Standard if the 
Board determin es the dimension lumber rules 
therein fail to conform to the provisions of the N a-
tional Grading Rule for dimension lumber esta b-
lished pursu ant to Section 11 of this Standard. 
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 10.5 Accreditat ion functions --Upon appl i-
cation, the Board shall exam ine and accr edit 
rules -writing agencies and non -rules -writing 
agencies as conforming to the r equirements of this 
Standard and to additional requirement s esta b-
lished by the ALSC. Accreditation shall be su bject 
to these conditions: 
10.5.1 The competency, re liability, a nd adequ a-
cy of the facilities provided by agencies participa t-
ing in this program for the purposes of lumber 
certification, inspection, rein spection, or superv i-
sion of grade marking. 
10.5.2 The adequacy of the procedu re followed 
in authorizing mills to gra de mark when provi d-
ing adequate supervisory service. 
10.5.3 The continuing conformance of grading 
rules to this Standard. 
10.5.4 The con tinuing competency and adequ a-
cy of performance of ag encies. 
10.6 Withdrawal o f accreditation --If at 
any time the pra ctices of any accredited agency 
are found not in conformity with this Standard 
and other requirements adopted by the ALSC, 
and if, after du e notice in writing to that effect, 
according to est ablished procedures, those prac-
tices shall not have b een brought into conformity 
with such standards and other requirements by 
the agency concerned, the Board is empowered to 
revoke all previous accredita tion granted that 
agency. 
10.7 Actions of Board --In all actions in rel a-
tion t o the certification of grad ing rules, a ccredit a-
tion of agencies and inspection facilities, and 
grade marking practices, the Board shall proceed 
in a fair and nondiscriminatory ma nner giving 
full and due consideration to the past e xperience 
and performance of agencies seeking accredi ta-
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 f acilities shall be 
establis hed, 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 insp ec-
tion and certification sh all be accre dited. Inspe c-
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 t imes on equal 
terms to any affected par ty. The Board's facilities 
shall also be available to all lumber inspection 
agencies, without favor or discrimination and 
without any requi rement for joining or otherwise 
subscribing to any t rade association or su pporting 
any service or activit y other than those of gra ding, 
standardization, grade marking, and inspection 
that fall within the jurisdiction of the Board. 
10.9 Enforcement --The Bo ard 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 a ffected by 
a decision or action of the Board shall have the 
right to require t he Board to hold a hearing at 
which suc h 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-
cordanc e with procedures established by the 
Board. 
10.11 Reports of action --The Boar d shall 
within 30 days foll owing an off icial action make 
such off icial action public. 
11. NATIONAL GRADING RULE 
COMMITTEE 
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    2 11.1 Autonomy of NGRC --The National 
Grading Rule Comm ittee (NGRC) shall be an a u-
tonomous body functioning under by -laws (provi d-
ing, among other things, for th e appointmen t 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 rat ios, nomencl ature, 
and descriptions of grades for dimension lumber 
conforming to this Standard. Grading rules of an 
agency shall not be cer tified as co nforming to this 
Standard if the Board d etermines that the dime n-
sion lumber rules therein fai l 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 th e interest 
of obtaining balanced views, the NGRC sha ll be 
composed of persons representing the following 
that desire to partic ipate: 
Organization Number of 
Members 
Southern Pine Inspection Bureau 2 
Western Wood Products Association 2 
Pacific Lumber Inspection Bureau West Coast 
Lumber Inspection Bureau 2 
Redwood Inspection Ser vice 1 
Northeastern Lumber Manufacture rs 
Association, Inc. 21 
Northern Softwood Lumber Bureau 1 
International Code Council 1 
National Fire Protection Association 1 
National Association of Home Builders 1 
National Lumber Grades Authority Canadian 
Inspection Agencies 1 
American Society of Civil Engineers 1 
American Institute of Architects 1 
Consumer Organization s 1 
Lumber Wholesalers 1 
Lumber Retailers 1 U.S. Non-rules W riting Agencies 
Ex officio, non -voting members shall be appointed 
from the following Federal agencies that desire to 
participate: 
Department of Housing and Urban 
Develo pment 1 
Defense Logistics Agency 1 
Forest Products Laboratory 1 
National Insti tute of Standards and 
Technology 1 
11.4 Appointment of members and 
chairman --Memb ers of the NGRC shall be co m-
petent in t he field of lumber technology. Every 
five years each organization or group of organiz a-
tions desiring to participate and entitled to repr e-
sentation shall appoint a principal member and 
alternate for each member to whic h it is entitled. 
The ALSC shall appoin t 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 N GRC from among its 
members. 
11.5 Transaction of business —A majority 
of members rep resenting rules -writing age ncies 
and a majority 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 Standard s9 
D9-12 Standard Terminol ogy Relating to Wood 
and Wood Based Products 
9 ASTM Standard s are available from ASTM International, 
100 Barr Harbor Drive, West Conshohocken, PA 19248 -
2959; tel ephone (610) 83 2-9500; www.astm.org . 
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 D1165 -183 Standard Nomenclature of Commer -
cial Hardwoods and Softwoods 
D4444 -183 Standard Test Methods fo r Laborato -
ry Standardization and Calibration of 
Hand -Held Moisture 
Meters 
SI10-1602 IEEE/ASTM SI 10 American Nation al 
Standard for Use of the International 
System of Units (SI): The Modern Metric 
System 
12.2 Other publications 
Little, Elbert, Jr., Checklis t of United States Trees 
(Native and Naturalized) , Agriculture 
Handbook No. 54 1, Forest Service, U.S. 
Department of A gricu lture, Was hington 
DC 20090 -6090, 1979. 
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   APPENDIX A COMMERCIAL NAMES OF THE PRINCIPAL SOFTWOOD SPECIES 
The commercial names listed b elow 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 stre ss-graded 
lumber, the species to be associated with a commercial name will be determined in accordance wi th 
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 lu mber manufactured from hardwood species or lumber 
manufactured from forei gn species when the species is included in rules certified by the Board of R e-
view. The information contained herein is a partial list of comme rcial names of the principal softwo od 
species and species groups. Additional species and species groups are provi ded 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 Ced ar 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 w hite-cedar T. occidentalis 
Southern Whi te Ce dar Atlantic white -cedar Chamaecyparis thyoides 
CYPRESS12 
Baldcypress baldcypress Taxodium distichum 
Pond cypress pond cypress T. dist ichum var. nutans 
DOUGLAS FIR Formatted: Font: Bold 
Douglas Fir13 Douglas -fir Pseudotsuga menziesii 
Bigcone Douglas fir Bigco ne Douglas f ir P. macrocarpa 
FIR: 
Balsam Fir14 balsam fir Abies balsamea 
10 The c ommercial names for species represent those commo nly accepted. Some grading rules certified by the Board provid e 
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 na mes for lumb er. 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 a re sometimes designated. 
12Cypress includes types designated as Red Cypress, White Cypress, and Yel low Cypress. Red Cypress is frequently classified 
and sold separately from the other types. 
13 Douglas fir from Arizona, Colorad o, Nevada, New Mexico and Utah is recognized as Douglas fir -South. 
14 Balsam f ir lumber is sometimes designated either as Easter n fir or as Balsam. 
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               Fraser Fir Fraser fir A. fraseri 
Douglas Fir15 Douglas -fir Pseudotsuga menzies ii 
Commercial Official Common 
Species or Species Group Names8 Tree Names9 Botanical Names 
FIR (continued ) 
Fraser Fir Fraser fir A. fraseri 
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. grand is 
Pacific G rand Fir Pacific silver fir A. amabilis 
White Fir white fir A. concolor 
HEMLOCK: 
Carolina Hemlock Carolina hemlock Tsuga caroliniana 
Easte rn Hemlock eastern hemlock T. canadensis 
Mountain Hemlock mountain hemlock T. mertensiana 
Western Hemlock western hem lock 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 lar ch Larix occidentalis 
Tamar ack tamarack L. laricina 
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. bank siana 
Limber Pine limber pine P. flexilis 
Lodgepole Pine lodgepole pine P. contorta 
Norway Pine red pine P. resinosa 
Pitch Pine pitch pine P. rigida 
Ponde rosa Pine ponderosa pine P. ponderosa 
Radiata /Monterey Pine Monterey pine P. radiata 
Sugar Pine sugar pine P. lamb ertiana 
Whitebark Pine whitebark pine P. albicaulis 
Idaho White Pine western white pine P. monticola 
Northern White Pine eastern white pine P. strobus 
15 Douglas fir from Arizona, Colorado, Nevada, New Mexico and Utah is recognized as Douglas fir -South. 
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 Commercial Official Common 
Spec ies or Species Group Names8 Tree Names9 Botanical Names 
PINE (continu ed) 
Longleaf Pine16 longleaf pine P. palustris 
slash pine P. elliottii 
Southern Pine (Major) loblolly pine P. taeda 
longleaf pine P. palustri s 
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. gla uca 
Blue Spruce blue spr uce P. punge ns 
Engelmann Spruce Engelmann spruce P. engelmannii 
Sitka Spruce Sitka spruce P. sitchensis 
Norway Spruce Norway spruce P. abies 
YEW: 
Pacific Yew Pacific yew Taxus brevifolia 
16 The commercial requirements for Longleaf Pine lumber are that not only must it b e produced from trees of the botanical 
species of Pinu s elliot tii and Pinus palustris , but each piece in addition must average either on one end or the other not less 
than six an nual rings per inch and not less than one -third summerwood. Longleaf Pine lumb er is sometimes designated as 
Pitch Pine in the ex port trade. 
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 APPENDIX B DEFINITIONS OF TERMS U SED IN DESCRIBING 
STANDA RD GRADES OF LUMBER 
B1. IEEE/ASTM SI 10-2002 was used as the Unfortunately, many old er handbooks and di c-
authorit ative standard in developing the metric tionaries and so me current references still co n-
dimensions found in this Standard. Metric di- tain erroneous or vague information about vo l-
mensions are calculated at 25.4 millimeters ume conversions to SI metric. The amount of 
(mm) times the dressed dimension in inches. The dressing can also affe ct the cross -sectional d i-
nearest mm is signif icant for dimensions greater mensions. Therefore, use extra care when ma k-
than 1/8 inch, and the nearest 0.1 mm is signif i- ing conve rsions from NOMINAL boar d foot to 
cant for dimensions equal to or less than 1/8 actual cubic meters. 
inch. 
In case of a dispute on size measurements, the 
The rounding rule for dimensions greater than conventional (inch) method of measurement 
1/8 inch: if the digit in the tenths of mm p osition shall take prec edence. 
(the digit after the decimal point) is less than 5, 
drop all fractional mm digits; if greater than 5 or B2. Defin itions of terms used in descri b-
it is 5 followed by at least one non -zero digit, ing sta ndard grades of lumber: 
round one mm high er; if 5 followed by only z e-
roes, retain the digit in the unit position (the air dried --seasoned by exposure to the atmo s-
digit before the decimal point) if it is even or i n- phere, in the open or under cover, without 
crease it one mm if it is odd. artificial heat. 
The rounding rule for dimensions equal to or all-heart --of heartwood throughout; that is, free 
less than 1/8 inch: if the digit in the hundredths of sapwood. 
of mm position (the second digit after the dec i-
mal point) is less than 5, drop all digits to the annual ring --denotes the amount of growth for 
right of the tent hs position; if greater than 5 or it a tree in a single year. 
is 5 followed by at least one non -zero digit, round 
one-tenth mm higher; if 5 followed by only zeros, bark pocket --patch of bark part ially or wholly 
retain the digit in the tenths position if it is even enclosed in the wood . Classified by size the 
or increase it one -tenth mm if it is odd. same as pitch poc kets. 
CAUTION: Use great c are when converting bevel siding —a board that has been resawn d i-
board feet, based on NOMINAL cross -sectional agonally to be used to clad the exterior of a 
dimensions, to cubic met ers of lumber, based on building. 
DRESSED cross -sectional dimen sions. This is rabbeted bevel siding —bevel siding 
explained on page 32 of the IEEE/ASTM SI 10 - with a rabbeted joint milled on the 
2002 by the followi ng note: “(9) No conversion is reverse of the thick edg e to facilit ate 
given for “board foot” because “board foot” is not alignment of pieces. 
a well -defined unit of volume. Calc ulation of the 
number of board feet in a piece of lumber is blemish --anything marring the appearance of 
based on the nominal dimensions of the cross lumber. 
section.” 
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 bow--see WARP. very light chip marks --not over 0.4 mm 
(1/64 inch) deep. 
boxed heart --with the pith enclosed in the light chip marks -not over 0.8 mm (1/32 
piece. inch) deep. 
medium chip marks --not over 1 .6 mm 
bright --unstained. (1/16 inch) deep. 
heavy chip marks --not over 3.2 mm (1/8 
burl --a distortion of grain, usually caused by inch) deep. 
abnorma l growth due to injury o f the tree. 
The effect of burls is assessed in relation to clear--free or practically free of all blemishes, 
knots. characte ristics, or defects. 
ceiling -a piece of patterned, tongue and grooved compression wood --abnormal wood that forms 
lumber, used to cover the ceiling of a room, on the underside of leaning and crooked c o-
porch or other partially enclosed areas. niferous trees. It is characterized, aside from 
its distinguishing color, by being hard and 
check --a separation of the wo od normally occu r- brittle and by its relati vely lifeles s appea r-
ring ac ross or thro ugh the annual rings and ance. Compression wood shall be limited in 
usually as a result of seasoning. effect to other appearance or strength redu c-
roller check --a crack in the wood stru c- ing characteri stics permitted in the grade. 
ture caused by a piece of cupped lu m-
ber bein g flattened in passing b e- corner--the intersection of two adjacent faces. 
tween the machine rol lers. 
surface check --a separatio n that occurs crook --see WARP. 
on a face of a piece. 
small check --not over 0.8 mm (1/32 cross break --separation of the wood a cross the 
inch) wide or 102 mm (4 inch) long. width. 
medium check --not over 0.8 mm (1/32 
inch) wide or 254 mm (10 inch) long . crosscutting --cutting with a saw across the 
large check --over 0.8 mm (1/32 inch) width. 
wide or longer than 254 mm (10 inch) 
or both. cup--see WARP. 
through check --a separation that e x-
tends from one surface of a piece to cutting --resulting pieces after crosscutting 
the opp osite or adjoining surface. and/or ri pping. 
chipped grain --a barely perceptible irregular i- decay (unsound wood) --a disintegration of the 
ty in the surfac e of a piece caused when pa r- wood substance due to action of wood -
ticles of wood are chipped or broken below destroying fungi, and is also known a s dote 
the lin e of cut. It is too smal l to be clas sed as or rot. 
torn grain and is not considered unless in e x- advanced decay --an older stage of decay 
cess of 25 percent of the surface involved. in which disintegration is recognized 
because the wood has become punky, 
chip marks --shallow depressions or indent a- soft, spongy, stringy, shaky, pi tted, or 
tions on or in the surface of dressed lumber crumbly. Decided discoloration or 
caused by shavings or chips getting embed- bleaching of the rotted wood is often 
ded in the surface during dres sing. apparent. 
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 heart center decay --a localized decay more subject to decay than pieces 
developing along the pith in some which do not co ntain it. 
species and is detected by visual i n-
spection. Heart center decay develops degrades --pieces which on reinsp ection prove of 
in the living tree and does not pr o- lower quality than the grade in which they 
gress further a fter the tree is cut. were shipped. 
honeyco mb--similar to white spe cks but 
the pockets are larger. Where permi t- diagonal grain --a deviation in the slope of 
ted in the grading rules, it is so li m- grain caused by sawing at an angle w ith the 
ited that it has no more effect on the bark of the tree. See SLOPE OF GRAIN. 
intended use of the piece than ot her 
chara cteristics permitted in the same dry--lumber of less than nomin al 5-inch thic k-
grade. Pieces containing honeycomb ness whic h has been s easoned or dried to a 
are no more subject to de cay than maximum moisture content of 19 percent. 
pieces which do not contain it. Lumber of nominal 5 -inch or greater in 
incipient decay --an early stage of decay thickness (timbers) is often manufactured 
in which disintegration of the wood and sold without drying. When the max i-
fibers has not pr oceeded far enough to mum moi sture content is specified for l umber 
soften or otherwise change the har d- of nominal 5 -inch or greater t hickness, it 
ness of the wood perceptibly. It is shall be in accordance with the provisions of 
usua lly accompanied by a sli ght di s- the applicable lumber grading rules cert ified 
color ation or bleaching of the wood. by the Board, which for some species defines 
peck --channeled or pitted areas or poc k- dry lumber as having a maximum moisture 
ets found in cedar and cypress. Wood content higher than 19 percent [see 2.7]. 
tissue between pecky areas remains 
unaffected in appearance and eased edge --slightly ro unded surfacing on pie c-
strength. All further growth of the es of lumber to remove sharp corners. Note: 
fungus cau sing peckiness ceases afte r Lumber nominal 4 inch or less in thickness is 
the trees are felled. frequently shipped with eased edges unless 
pecky --characterized by PECK otherwise specified. 
pocket rot --decay which appears in the 
form of a hole, pocket, or area of soft edge --either : 1) the narrow face of recta ngular -
rot, usually su rrounde d by apparently shaped pieces, or 2) the corn er of a piece at 
sound wood. the intersection of two longitudinal faces, or 
water soak or stain --water -soaked area 3) in stress grades, that part of the wide face 
in heartwoo d, usually interpreted a s nearest the corner of the piec e. 
the incipi ent stage of certain wood 
rots. edge grain (EG) [vertical grain (VG)] [rift 
white specks --small white or brown pits grain] --a piece or pieces sawn at approx i-
or spots in wood caused by the fungus mately right angles to th e annual growth 
Fomes pini . It develops in the living rings so that the rings form an angle of 45 
tree and does not develop further in degrees or more with the surface of the piece. 
wood in service. Where permitted i n 
grading rules, it is s o limited th at it equilibrium moisture content – the moisture 
has no more effect on the intended content at which wood neither gains nor lo s-
use of the pieces than other chara c- es moisture when surround ed by air at a gi v-
teristics permitted in the same grade. en rel ative humidi ty and temperature. 
Pieces containing white spe ck are no 
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 finish -a high -quality piece of lumber graded for gum str eak--a well -defined accumulation of 
appearance, often used for interior trim or gum in more or less regular streak. Class i-
cabinet work. fied as pitch streaks. 
firm red hear t--a stage of incipient decay cha r- heart center --the pith or center core of the log. 
acterized by a reddish color in the heartwoo d 
which does not render the wood unf it for the heart face --face side free of sapwood. 
majority of yard pu rposes. 
heart shake --see SHAKE --PITH SHAKE. 
flat grain (FG) [slash grain (SG)] --a piece or 
pieces sawn approximately parallel to the heartwood --the inner core of the tree trunk 
annual growth rings so that all or some of comprising the annual rings containing non -
the rings form an angle of less than 45 d e- living elements. In some species, heartwood 
grees w ith the surface of the p iece. has a prominent color different from sap-
wood. Heartwood and sapwood of equiv alent 
flooring-a tongue and grooved piece of lumber chara cter are compared as follows : 
typically used as a finished floor. with regard to strengt h, heartwood 
and sapwood are equal. No requir e-
f.o.h.c. (free of heart centers) --without pith ment of heartwood is made when 
(side cut). An oc casional piece, when showing strength alone is the gover ning factor. 
pith for not more than 1/4 the length on the with regard to durability , heartwood 
surface, shall be accepted. is more d urable than sapwood. When 
wood is to be exposed to decay -
free of wan e--without wane but with either producing co nditions without pr e-
eased or square edges. (see WANE) servative treatm ent, it is permissible 
to specify the minimum percentage of 
grain --the fibers in wood and their direction, heartwood to be present in all pieces 
size, a rrangement, appearanc e, or quality. of lumber in a shipment. 
with regard to pres ervatives, sapwood 
green --lumber of less than nominal 5 -inch takes preservative treatment more 
thickness, which has a moisture content in readily than hear twood. 
excess of 19 percent. For lumber of nominal 
5-inch or greater thickness (timbers), green hit-and-miss --a series o f skips not over 1.6 mm 
shall be defined in accordance with the pr o- (1/16 inch) deep with surfaced areas b e-
visions of the applicab le lumber grading tween. 
rules certified by the Board [See 2.11]. 
hit-or-miss --lumber that is completely or partly 
gum pocket --an ope ning between growth ring s surfaced or entirely rough with a maximum 
which cont ains or has contained resin, or scantness of 1.6 mm (1/16 inch). 
bark, or both. 
holes --openings that either extend p artially or 
gum seam --check or shake filled with gum. wholly throu gh a piece. An alternate desi g-
nation for holes which extend only partially 
gum spot --an accumulation of gumlike su b- through a piece is surface pits. Holes are 
stance occu rring as a small patch. Often o c- class ified by size as follows: 
curs in conjunction with a bird -peck or other pin hole--not over 1.6 mm (1/16 inch) in 
injury to the growing wo od. diameter. 
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   medium hole --(small hole) not o ver 6 black knot --results from a dead b ranch 
mm (1/4 inch) in d iameter. which the wood growth of the tree has 
large hole --not over 25 mm (1 inch) in surrounded. 
diameter. decayed knot --softer t han the surroun d-
very large hole --over 25 mm (1 inch) in ing wood , and contai ning advanced 
diameter. decay. 
encased knot --not intergrown with the 
kiln-dried --seasoned in a chamber by means of annual rings of the surrounding 
artificial heat. wood. 
firm knot -solid across its face but co n-
knife marks --the imprints or markings of the tains incipient decay. 
machine knives on the surface of dress ed fixed knot --retains its place in dry lu m-
lumber. ber under ordinary co nditions but is 
very slight knife marks --marks that movable under pressu re though not 
are visible only from a favorable angle easily pushed out. 
and are perfectly smooth to the touch. hollow knot --a sound knot containing a 
slight knife marks --marks th at are hole greater than 6 mm (1/4 inch) in 
readily visible but evidence no un e- diameter. The through opening of a 
venness to the touch. hollow knot is limited to the size of 
other holes permitted. 
knot --a porti on of a branch or limb t hat has b e- intergrown knot —a knot whose annual 
come incorporated in a piece of lumber. In rings are parti ally or completely i n-
lumber, knots are classified as to form, size, tergrown on one or more faces with 
quality, and occurrence. the annual rings of the surrounding 
wood. 
knot form -- loose knot --not firmly fixed; a knot not 
oval knot --produced when the limb is held tightly in place by growth, shape, 
cut at slightly more than a right angle or position. 
to the long axis . pith knot --sound in all resp ects except it 
round knot --produced w hen the limb is contains a pith hole not over 6 mm 
cut at approximately right angles to (1/4 inch) in diameter. 
its long axis. red knot --knot that results from a live 
spike knot --produced when the limb is branch grown in the tree and is inte r-
cut either lengthwise or diagonally. grown with the su rrounding wood. 
sound knot --contains no decay. 
knot size -- star-checked knot --has radial checks. 
pin knot --not over 13 mm (1/2 inch) in tight knot --so fixed by gr owth, shape, or 
diameter. position that it retains its place in the 
small knot --not over 19 mm (3/4 inch) in piece. 
diameter. unsound knot --contains decay. 
medium knot --not over 38 mm (1 -1/2 water -tight knot --has annual rings 
inch) in d iameter. completely intergrown wi th those of 
large knot --over 38 mm (1 -1/2 inch) in the surrounding wood on one surface 
diameter. of the piece, and it is sound on that 
surface. 
knot quality --
knot occurrence --
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  branch knots --two or more divergent machine gouge--a groove cut by the machine 
knots sawed lengthwise and tapering below the desired line. 
toward the pith at a common point. very light machine gouge --not over 0.4 
corner knot --located at the inters ection mm (1/64 inch) deep. 
of adjacent faces. light machine gouge --not over 0.8 mm 
knot cluster --two or more knots grouped (1/32 inch) deep. 
together as a unit with the fibers o f medium machine gouge --not over 1.6 
the wood d eflected around the entire mm (1/16 inch) deep. 
unit. A group of single knots is not a heavy machine gouge --not over 3.2 mm 
knot cluster. (1/8 inch) deep. 
single knot --occurs by itself. The fibers very heavy machine gouge --over 3.2 
of the wood being de flected around it. mm (1/8 inch) deep. 
loosened grain --a grain separation or loosening machine offset --an abrupt dre ssing variation in 
between sp ringwood and summerwood with- the edge surface which usually occurs near 
out di splacement. the end of the piece without reducing the 
very light loosened grain --not over 0.4 width or without changing the plane of the 
mm (1/64 inch) separation. wide surface. 
light loosened grain --not over 0.8 mm very light machine offset --a variation 
(1/32 inch) separation. not over 0.4 mm (1/6 4 inch). 
medium loosened grain --not over 1.6 light machine o ffset--a var iation not 
mm (1/16 inch) separation. over 0.8 mm (1/32 inch). 
heavy loosened gra in--not over 3.2 mm medium machine offset --a variation 
(1/8 inch) separ ation. not over 1.6 mm (1/16 inch). 
very heavy loosened grain --over 3.2 heavy machine offset --a variation not 
mm (1/8 inch) separation. over 3.2 mm (1/8 inch). 
very heavy machine offset --a variation 
lumber --Lumber is defined as a manufactured over 3.2 mm (1/8 in ch). 
product derived from a log through sawing or 
planing . metric units —See B 1. 
machine bite --a depressed cut of the machine mismanuf acture --includes all defects or ble m-
knives at the end of a piece . ishes, produced in manufacturing. See 
very light machine bite --not over 0.4 CHIPPED GRAIN, HIT -AND -MISS, HIT -
mm (1/64 inch) deep. OR-MISS, LOOSENED GRAIN, MACHINE 
light machine bite --not over 0.8 mm BURN , MACHINE GOUGE, MISMATCHED 
(1/32 inch) deep. LUMBER, RAISED GRAIN, SKIP, TORN 
medium machine bite --not over 1.6 mm GRAIN, and VAR IATION IN SAWING. 
(1/16 inch) deep. 
heavy machine bite --not over 3.2 mm misma tch--an unev en fit in worked lumber 
(1/8 inch) deep. when a djoining pieces do not meet tightly at 
very heav y machine bite --over 3.2 mm all points of contact or when the surfaces of 
(1/8 inc h) deep. adjoining pieces are not in the same plane. 
slight mismatch --a barely evident trace 
machine burn --a darkening of the wood due to of mi smatch. 
overheating by machine knives or rolls when very lig ht mismatch --not over 0. 4 mm 
pieces are stopped in the machine. (1/64 i nch). 
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    light mismatch --not over 0.8 mm (1/32 large pitch streak --not over 1/4 the 
inch). width by 1/2 the length of the su rface. 
medium mismatch --not over 1.6 mm very large pitch streak --over 1/4 the 
(1/16 inch). width by 1/2 the length of the su rface. 
heavy mismatch --not over 3.2 mm (1/8 
inch). pith--the small soft core in the struc tural center 
of a log. 
mixed grain (MG )--either vertical or flat very small pith --not over 3.2 mm (1/8 
grained pieces or both. inch) wide and occupies on the face 
surface not over 161 square mm (1/4 
moisture co ntent--the weight of the water in a square in ch) [3.2 mm by 51 mm (1/8 
piece of lumber expressed in a percentage of inch wide by 2 inch long), or 1.6 mm 
the weight of the piece after being over dried. by 102 mm (1/16 inch by 4 inch)] 
small pith--not ov er 484 square mm (3/4 
occasional pieces --not more than 10% of the square inch) on the face surface [6 
pieces in a parcel or shipment. mm by 76 mm (1/4 inch by 3 inch), 5 
mm by 102 mm (3/16 inch by 4 inch), 
partition —a tongue and grooved piece of lu m- 3.2 mm by 15 2 mm (1/8 inch by 6 
ber w ith the same pattern run on both sid es. inch), or 1.6 mm by 305 mm (1/16 
For use where both sides may be exposed. inch by 12 inch)] 
free of pith--the prohibition o f pith on or 
pitch --an accumulation of resinous material. within the body of the piece. 
light pitch --the light but evident pre s- boxed pith --pith that is within the four 
ence of pitc h. faces of an end of a piece. 
medium pitch --a somewhat more ev i-
dent presence of pitch than in the pocket --a well -defined opening, between t he 
light p itch. rings of annual growth, which develops du r-
heavy pitch --a ver y evident ac cumul a- ing the growth of the tree. It us ually contains 
tion of pitch showing by its color and pitch or bark. Pocket s are described as fo l-
consi stency. lows with equivalent areas being permiss i-
massed pitch --a clearly defined accum u- ble: 
lation of solid pitch in a body by i tself. very small pocket —1.6 mm (1/16 inch) 
in width and 76 mm (3 inch) in 
pitch seam --a shake or check which contains length , or 3.2 mm (1/8 inch) in width 
pitch. and 51 mm (2 inch) in length. 
small pocket —1.6 mm (1/16 inch) in 
pitch streak --a well -defined accumulation of width and 152 mm (6 inch) in length, 
pitch i n the wood c ells in a streak. Pitch or 3.2 mm (1/8 inch) in width and 102 
streaks, with equivalent areas being permi s- mm (4 inch) in length, or 6 mm (1/4 
sible, are described as follows: inch) in width and 51 mm (2 inch) in 
very small pitch streak —10mm (3/8 length. 
inch) i n width and 381 mm (15 inch) medium pocket—1.6 mm (1/16 inch) in 
in length. width and 305 mm (12 inch) in 
small pitch streak --1/12 the width and length, or 3.2 mm (1/8 inch) in width 
1/6 the length of the p iece. and 203 mm (8 inch) in length, or 10 
medium pitch streak --1/6 the width mm (3/8 inch) in width and 102 mm 
and 1/3 the length of the piece. (4 inch) in length. 
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 large pocket --not over 2581 square mm 
(4 square inches) in area. shake --a lengthwise separation of the wood 
very large pocket --over 2581 square which occurs between or through the rings of 
mm (4 square inches) in area. annual growth. 
closed pock et--an opening on one su r- fine shake --a barely perceptible ope ning. 
face only. light shake --not over 0.8 mm (1/32 inch) 
open (through) pocket --an opening on wide. 
opposite surfaces. A through opening mediu m shake --not over 3.2 mm (1/8 
is considered the same as a through inch) wide. 
hole of equal size. open shake --over 3.2 mm (1/8 inch) 
wide. 
raised grai n-a roughened condition of the su r- ring shake --occurs between the annual 
face of dressed lumber in which the hard rings to partially or wholly encircle 
summerwood is raised above the softer the pith. 
springwood, but not torn loose from it. surface shake --occurs on only one su r-
very light raised grain --not over 0.4 face of a piece. 
mm (1/64 inch). through shake --extends from one s ur-
light raised grain --not over 0.8 mm face of a piece to the opposite or to an 
(1/32 inch). adjoining surface. 
medium raised grain --not over 1.6 mm pith shake (hear t check or heart 
(1/16 inch). shake) --extends thr ough the annual 
heavy raised grain --not ove r 3.2 mm rings from or through the pith t o-
(1/8 inch). wards the surface of a piece, and is 
distinguished from a seasoning check 
resawn lumber --the product of sawing any by the fact that it s greatest width is 
thickness of lumber to develop thinner lu m- nearest the pith, whereas the greatest 
ber. width of a season c heck in a pith -
centered piece is far thest from the 
ripped lumber --the product of sawing any pith. 
width of lumber to develop narrower lumber. 
side cut --pith is not enclosed within the four 
sapwood --the outer layers of growth between sides of the piece. 
the bark and he artwood that contain the sap. 
bright sapwood --sapwood that shows no skip--area on a piece that failed to surface clean. 
stain and is not limited in any grade Skips are described as follows: 
unless specifically stated in the grade very light skip --not over 0.4 mm (1/64 
description. inch) d eep. 
sapwood restriction s waived --a lifting light skip --not ove r 0.8 mm (1/ 32 inch) 
of any restrictions in a rule on the deep. 
amount of sapwood per mitted in pie c- medium skip --not over 1.6 mm (1/16 
es graded under that r ule. inch) deep. 
bright sapwood no defect (BSND) --an heavy skip --not over 3.2 mm (1/8 inch) 
indication that bright sapwood is deep. 
permitted in each piece in any 
amount. slope of grain --the deviation of t he line of fibers 
from a straight line parallel to the sides of 
seasoning --evaporation or e xtraction of moi s- the piece. 
ture from green or partially dried wood. 
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 softwood --one of the group of trees wh ich have confused with natural red heart. Na t-
needle -like or scale -like leaves. The term has ural color is usually uniformly dis-
no specific reference to the softness of the tributed through cer tain annual rings, 
wood. whereas stains are usually in irreg u-
lar patches. 
sound --free of decay. stained sapwood --sapwood with disco l-
oration. In grades when it is permi t-
spiral grai n--a deviation in the slope of grain ted, stained s apwood has no more e f-
caused when the fibers in a tree take a s piral fect on the intended use of a piece 
course around the trunk of the tree instead of than other characteri stics permitted 
the normal vertical course. in the g rade but it does affect appea r-
ance in varying d egrees: 
split --a separation of the wood through the piece light stained sapwood --a disco l-
to the opposite surface or to an adjoining su r- oration so slight that it does 
face due to the tearing apart of the wood not affect natural fi nishes. 
cells. medium s tained sapwood --a 
very short split --equal in le ngth to 1/2 pronounced difference in colo r-
the width of the piece. ing. Note: Sometimes the us e-
short split --equal in length to the width fulness for natural finish es but 
of the piece and in no case exceeds 1/6 not for paint finishes is affec t-
the length. ed. 
medium split --equal in length to twice heavy stained sapwood --a so 
the width of the piece and in no case pronounced di fference in color 
exceeds 1/6 the length. that the grain of the wood is 
long split --longer than a medium split. obscured, but lumber c ontain-
ing it is acceptable for paint 
springwo od--the port ion of the annual ring finishes. 
formed during the early part of the yearly stained wood resulting from exp osure 
growth period. It is lighter in color, less to the elements --discolored wo od 
dense, and not as strong mechani cally as that is permitted in all grades of 
summe rwood. framing and sheathing lumber. 
square corners --without eased edges but has stepping -lumber designed to be used for stair 
an allo wance for wane in certain gra des. treads. Customarily surface d three sides and 
bull-nosed on one edge. 
square edged --free from wane and without 
eased edges. stress grades --lumber having assign ed working 
stresses and modulus of e lasticity values in 
stained wood --a discoloration in wood. accordance with accepted basic principles of 
stained heartwood or firm red heart -- strength grading, and the provisions of 
heartwood that sh ows a marked var i- 6.3.2.1 and 6.3.2.2 of this Standard. 
ation from the natural color. In 
grades where it is permitted , stained summerwood --the portion of the annual ring 
heartwood has no more effe ct on the formed during the latter part of the yearly 
intended use of a piece than other growth. It is darker in c olor, more dense, and 
characteristics permitted in the stronger mechanically than sprin gwood. 
grade. Note: Stained heartwood ran g-
es from pink to brown, and is not to be 
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     torn grain --an irregularity in the surface of a combination thereof. Warp restrictions are 
piece where wood has been torn o r broken based on the average for m of warp as it o c-
out by surfacing. curs n ormally, and any variation from this 
very light torn grain --not over 0.4 mm average form, such as short kinks, shall be 
(1/64 inch) deep. appraised according to its equivalent effect. 
light torn grain --not over 0.8 mm (1/32 Pieces containing two or mo re forms of warp 
inch) deep. shall be a ppraised according to the combined 
medium torn grain --not over 1.6 mm effect in determ ining the amount permiss i-
(1/16 inch) deep. ble. In gra ding rules, warp is classified as 
heavy torn grain --not over 3.2 mm (1/8 very light, light, medium, and heavy, and 
inch) deep. applied to each width and length as set forth 
very heavy torn grain--over 3.2 mm in the various grade s in accordance with the 
(1/8 inch) deep. following prov isions: 
bow--a deviation flatwise from a straight 
trim --to cross -cut a piece to a given len gth. line drawn fr om end to en d of a piece. 
double -end trimmed (DET) --lumbe r It is measured at the point of greatest 
trimmed square on both ends. Tole r- distance from the straight line. 
ances are found in certified grading crook --a deviation edgewise from a 
rules. straight line drawn from end to end of 
precision -end trimmed (PET) --lumber a piece. It is measured at the point of 
trimmed square on both en ds to un i- greatest distance from the straight 
form lengths with a manufacturing line. 
tolerance of 1.6 mm (1/16 inch) ove r cup--a devia tion in the face of a piece 
or under in length in 20% of the p iec- from a straight line drawn from edge 
es. to edge of a piece. It is measured at 
square -end trimmed --lumber trimmed the point of greatest distance from the 
square and having a manufacturing straight line. 
tolerance of 0.4 mm (1/64 inch) for twist --a deviation flatwise, or a combin a-
each nominal 2 inch of thickne ss or tion of flatwise and edgewise, in the 
width. form of a curl or s piral, and the 
amount is the distance an edge of a 
unsound -see DECAY. piece at one end is raised above a flat 
surface against which both edges at 
variation in sawing --a deviation from the line the opposite en d are res ting snugly. 
of cut. 
slight var iation --not over 1.6 mm (1/16 wavy dressing --an involvement of more uneven 
inch) scant in nominal 1 -inch lumber, dressing t han knife marks. 
3.2 mm (1/8 inch) in nominal 2 -inch, 5 very li ght wavy dre ssing --not over 0.4 
mm (3/16 inch) in nominal 3 -inch to 7 - mm (1/64 inch) deep. 
inch, and 6 mm (1/4 inch) in nominal light wavy dressing --not over 0.8 mm 
8-inch and greater thickness or width. (1/32 inch) deep. 
medium wavy dressing --not over 1.6 
wane --bark or lack of wood from an y cause, e x- mm (1/16 in ch) deep. 
cept eased edges, on the edge or corner of a heavy wavy dressing --not over 3.2 mm 
piece of lumber. (1/8 inch) deep. 
very heavy wav y dressing --over 3.2 mm 
warp --any deviation from a true or plane su r- (1/8 inch) d eep. 
face, i ncluding bow, crook, cup, twi st, or any 
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        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 appli cable to a particular re gion 
or spec ies shall not be used unless included in certified grading rules. 
Abbreviations are commonly used in the forms indicated, but variations suc h as the use of upper -
and lower -case type, and the use or omission of periods and other forms of punc tuation 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 Measur e 
Btr Better 
B&B or B& Btr B and be tter 
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 matche d 
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 he aded 
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 center bead one side 
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   E&CB2S Edge and center bead two sides 
E&CV1S Edge and center Vee one side 
E&C V2S 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 bo ard (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 Groove d roofing 
HB Hollow back 
H&M hit-and-miss 
H or M hit-or-miss 
Hrt Heart 
Hrt CC Heart cubical conte nt 
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 Thous and 
MBM Thousand (feet) board measu re 
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 
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   Pat Pattern 
Pc Piece 
Pcs Pieces 
PE Plain end 
PO Purchase order 
P&T Post a nd 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 ed ge 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 Surface d one side and one edge 
S1S2E Surfa ced 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 a nd center matched 
S2S&SM Surfaced two sides and standard matched 
S4S Surface d four sides 
S4S&CS Surfaced four s ides and caulking seam 
T&G Tongued and grooved 
VG Vertical grain 
Wdr Wider 
Wt Weight 
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   APPENDIX D IMPLEMENTATION AND MAINTENANCE OF STANDA RD 
D1. STANDING COMMITTEE National Institute of Standard s and 
Technology). The history o f R 16's dev elopment 
The American Lumber Standard Committee and its subsequent revisions is summarized in 
(ALSC) ac ts as the Standing Commi ttee for thi s editions issued, respectively, in 1924, 1925, 
Standard for the purpose of its interpretation 1926, 1929, 1939, and 1953. 
and for considering future proposals for 
amendments and revisions. Members of the R 16-53 was rev ised in 1969 and superseded by 
ALSC and th eir alternates are appointed by the Voluntary Product Standard PS 20 -70 American 
Secretary of Commerce in accordance with Softwood Lumber Standar d. The signi ficant 
Section 9 of this Standar d. The names of the provisions added to PS 20 -70 were: 1) separate 
members are available from the Committee's size standards for dry and green lumber, under 
secretariat: Standards Services Division , nominal 5 -inch thickness, were es tablished i n 
National Institute of Standards and Technology, order to achieve greater uniformity in the 
Gaithersburg, Maryland 20899 -2100. Comments dimensions of seasoned and unseasoned lumber 
regarding the Standard and suggesti ons for its at the po int of use; 2) an independent National 
amendment or revision ma y also be sent to this Grading Rule Committee was created to 
address. No product shall be advertised or establish and maintain a national grading rule 
represented in any manner that would imply for dimension lumber c onforming t o PS 20; 3) an 
approval or endorsement of that p roduct by the independent Board of Review was formed to 
National Institute of Standards and Technology assure uni form approval of grading rules a nd of 
and/or the Depart ment of Commerce. agenci es to grade under these rules, and to 
enhance enforcement of the accreditation 
D2. EFFECTIVE DAT E program ; 4) the composition of the American 
Lumber Sta ndard Commi ttee was expanded to 
Voluntary Product Standard PS 20 -2015, reflect a broader representation of interests; and 
American Softwood Lumber Standard , a 5) uniform methods for assi gnment of de sign 
voluntary standard developed under the values were accepted. Non -substantive changes 
Department of Commerce p roced ures, shall be were made to the Standard in 1985, 1991, 1992, 
effective April, 202015 for products produced 1999 , 2005 , and 2010, and 2015 . The Standard 
thereunder o n and after that date. The S tandard was reviewed in 20194 to assure it reflected the 
being superseded, American Softwood Lumber needs of manufactur ers, distributors and 
Standard PS 20 -1510, is effective for products consumers. 
produced thereunder through March , 202015. 
D4. CURREN T EDITION 
D3. HIST ORY OF THE STANDARD 
The current edition, PS 20 -2015, has the same 
Early in 1922 Secretary of Commerce Herbert technical requirements and administrative 
Hoover, respo nding to a request from the lumb er structure for implementing and enfo rcing the 
industry, offered the cooperation of the Standard as its previous edition. This new 
Department in activities directed toward edition was based on the recommendations 
simplification, standardization, and development resulting from an extensive te chnical and 
of adequate quality gua rantees for the lumber - editorial review of PS 20 -1510 conducted by the 
consuming public. This cooperation led to th e Standing Committee with the assistance from 
development and publication in 1924 of the National Institute of St andards and 
Simplified Practice Recommendation R 16 under Technology in 201914. 
the guidance of the Department's Division of 
Simplified Practices, which was to become a pa rt 
of the N ational Bureau of Standards (now the 
47