Voluntary Product Standard PS 20 -20 
Revision  1 
 
 
 
 
American  Softwood  Lumber Standard 
 
 
 
October 2021  
 
 
  
 
 
 
 
 
 
  
 
  
 
 
  
 
 
 
 
  
 
 
 
 
 
 
 
 
 
U.S. Department of Commerce 
Gina M. Raimondo, Secretary  
 
National Institute of Standards and Technology  
James K. Olth off, Performing the Non- Exclusive Functions and Duties of the Under Secretary of Commerce  
for Standards and Technology & Director, National Institute of Standards and Technology  
  2  
 
 
 
   
 
 
This page intentionally left blank.  
 
 
 
   
 
 
   
  3  
 
VOLUNTARY PRODUC T STANDARDS  
 
 
 
Development of Voluntary Product Stand ards  
 Voluntary P roduct Standards are developed 
unde r pro cedures published by the Department 
of Commerce in Title 15 Code of Federal Reg u-
lations Part 10, Procedures for the Development 
of Voluntary Prod uct Standards . The purpose of 
these standards is to establish nationall y rec-
ognized requirements for produ cts and provide 
all concerned interests with a basis for common 
understanding of the characteristics of the 
products. The National Institute of Standards and Technology (NIST) administer s the Volu n-
tary Pr oduct Standards P rogram on a reim-
bursable basis.  
 Role of NIST  
 The role of NIST in the establishment of Volu n-
tary Product Standards is to act as an unbiased 
coordinator in their development, provid e edito-
rial assistance in their preparation, supply such 
assistance  and rev iew as is required to assure 
their technical soundness, and to seek satisfa c-
tory resolution of valid points of disagreement. 
NIST also determines compliance with the cr i-
teria of the  Department’s procedures, provides 
secretarial functions f or each committee  ap-
pointed under the procedures, an d publishes 
the standards as public documents.  
 
Producers, distributors, users, consumers, and 
other interested groups contribute to the esta b-
lishment  of Voluntary Product Standards by i n-
itiating and participating  in thei r develo pment, providing technical or other counsel as appr o-
priate, promoting the use of and support for the 
standards, and assisting in keeping the stand-
ards current with respect t o advancing techno l-
ogy and marketing practices.  
 Use of Vo luntary Product S tandards  
 The use of Voluntary Product Standards is vo l-
untary. NIST has no regulatory power in the enforcement of their provisions: however, since the standards represent a consensus of  all in-
terested groups, their provisions are likely to  
become e stablished as trade customs. In add i-
tion, w hen a Voluntary Product Standard is 
made a part of a legal document, such as a sales contract or code, compliance with the standard 
is enforc eable . 
 
The benefits derived from Voluntary Product 
Standards are in dir ect proportion to their ge n-
eral recognition  and actual use. Producers and 
distributors whose products meet the requir e-
ments of a Voluntary Product Standard may re-fer to the standard in adve rtising and on labels 
to promote greater public understanding for confidenc e in their products. At times, purchas-
ers may order products conforming to the re-quirements of a Voluntary Product Standard.  
 For copies of the Voluntary Product Standards proce dure s or for more information concerning 
the development and use of the se stand ards, 
contact the Standards Coordin ation Office , Na-
tional Institute of Standards and Technology, Gaithersburg, MD 20899- 2100.   
 
 
      4  
  
 
 
    
 
This page intentionally left blank . 5  
 
 
   Voluntary Product Standard 
 PS 20 -20  Revision 1 
 (Supersedes Volunt ary Produ ct Standard PS 20 -20) 
   
 
 
AMERICAN SOFTWOOD LUMBER STANDARD  
  
PREFACE  
 
 
 The American Softwood Lumber Standard was d eveloped by the American Lumber  
Standard Committee (ALSC) i n accordance with the Pr ocedures for the Development of Voluntary 
Prod uct Sta ndards  of th e U.S. Department of Commerce. Th e ALSC membership is appointed by 
the Secretary of Commerce to constitute a proper balance among producers, distributors, and 
consumer s of softwood lumber. Pursuant to a U.S. District Court order, the ALS C and i ts Board 
of Review (Board) operate as indepen dent bodies with defined functions with regard to establis h-
ing, maintaining, implementing and enforcing this Standard. Through a conse nsus process, the 
ALSC maintains the Standard and establishes policies  and ad opts other s tandards by which the 
Board certi fies grading rules, approves design values, accredits agencies to grade and inspect u n-
der those rules and monitors the agencies' perfo rmance. The purpose of this standardization pro-
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 pro-
vides for the grading of structural lumber by both visual and mechanical means.   A separate con-
sensus body, the  National Grading Rule Committee (NGRC) is established to develop and main-
tain nomenclature and d escriptions of grades for dimension lumber that conform to this Stand-
ard. 
 
This Standard applies to domestic production consumed in and expo rted from the Un ited States, 
and for lumber imported into the United States.   6 ABSTRACT  
 
This Standard pertains to softwood lumber. It 
establishes standard sizes and requirements for 
development and coordination of the lumber 
grades of the various sp ecies , the assignment  of 
design values when called for, a nd the prepara-
tion of grading rules applicable to each species. It provides for implementation of the Standard 
through an accreditatio n and certification pr o-
gram to a ssure uniform industry -wide marking 
and in spection.  
 
It establishes principal trade classi fications 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 met hods in the grading, inspe c-
tion, measur ement and description of softwood 
lumber. It includes the organization and func-
tions of the Ame rican Lumber Standard Co m-
mittee, the Board of Review, and the Na tional  
Grading Rule Co mmittee. Commercial names of 
the pri ncipal softwood species, definitions of 
terms used in describing standard grades of lumber and commonly used industry abbrevi a-
tions ar e also provided.  
 
The Standard was developed by the American Lumber St anda rd Committee  in accordance 
with procedures of th e U. S. Department of 
Commerce.  
 KEY WORDS  
 
Accreditation ; ALSC Board of Review; certific a-
tion of grading rule; DOC PS 20 -20; lumber i n-
spection; lumber sizes; mois ture content of 
lumber; National Grading Ru le; softwood lu m-
ber standard  
  
 
 
  
 
 
 
  
  
 
 
 
  
 
 
 
  
 
 
 
  
 
 
 
   
 
    
 
    7 TABLE OF CONTENTS  
 
PREFACE  .................................................................................................................................  5 
1.  SCOPE  .................................................................................................................................  9 
2.  TERMINOLOGY  ................................................................................................................ 10 
3.  CLASS IFICATION  ............................................................................................................ 11 
4.  MEASU REMENT AND TALLY  ........................................................................................ 12 
5.  LUMBER SIZES  ................................................................................................................ 13 
6.  GRADING RULE REQUIREMENTS  ............................................................................... 18 
7.  GRADE MARKING (GRADE STAMPING)  ...................................................................... 21 
8.  INSPECTION AND REINSP ECTION  .............................................................................. 22 
9.  AMERICAN LUMBER STANDARD COMMITTEE......................................................... 24 
10.  BOARD OF REVIEW  ....................................................................................................... 26 
11.  NATIONAL GRADING RULE COMMITTEE ................................................................ 29 
12.  REFERENCES  ................................................................................................................. 30 
APPENDIX A  COMMERCIAL NAMES OF THE PRINCIPAL SOFTWOOD SPECIES  .... 31 
APPENDIX B  DEFINITIONS OF TERMS USED IN DESCRIBING  
STANDARD GRADES O F LUMBER ............................................................... 34 
APPENDIX C   LUMBER INDUSTRY ABBREVIATIONS  .................................................. 44 
APPENDIX D  IMPLEMENTATION AND MAINTENANCE OF STANDARD  .................. 47 
  8  
  
 
 
    
This page intentionally left blank .  9 AMERICAN SO FTWOOD LUMBER STANDARD  
 
 
 
Effective October 2021  
 
 
 
[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 Commerc e to supersede PS 20-20 Revision  1 “American Softwood Lumber Sta ndard.”]  
 
 
 
1.  SCOPE  
 
1.1 General  
 1.1.1 This Voluntary Product Standard estab-
lishes and maintains, through a consensus pr o-
cess and in the public interest, standard sizes (both in  metric
1 and conv entional units) and ge n-
eral requirements for developing  grades of sof t-
wood lumber . It is implemented through an i n-
ternationally recognized accreditation and certi-
fication program, the purpose of which is to pro-vide for uniform, industry -wide grade marking 
and i nspe ction of soft wood lumber.  
 
1.1.2 This Standard  also provides a basis for 
the coordination of the grades of the various sp e-
cies of softwood lumber, the assignment of design 
values to lumber when called for, and the prep a-
ration of g rading rules appl icable to each species . 
The provisions of this Standard  apply to stru c-
tural lumber manufactured from hardwood sp e-
cies or lumber manufactured from foreign species when the species is included in rules certified by 
the Board of Review. It is  not intended to be us ed 
either as grad ing rules or as purchase specifica-
tions. Italicized notes in this Standard are non-
mandatory.  
 
1 Metric units are provided initially follow ed by conventio n-
al units.   1.1.3  This Standard establishes the principal 
trade class ifications and sizes of softwood lumber 
for yard, structural, fac tory and shop use. It pro-
vides for th e classificati on, measurement, grad-
ing and grade marking of rough and dressed siz-es of va rious items of lumber including finish, 
boards, dimension and timbers. Terms and pro-
cedures are defined and discussed to provide a  
basis for the use of uniform methods  in the grad-
ing, inspection, measur ement and description of 
softwood lumber.  
 Note:  The provisions of this Standard do not a p-
ply to the myriad of products of remanufacture 
(for example: turned balusters, peeler cores, e tc.) 
or manufa ctured components (for  example: trus s-
es, lattice panels, I-joists, etc.) that use  “American 
Lumber Standard”  (ALS ) program lumber as a 
raw material.  
 1.1.4  This Standard applies to lumber that is 
to be iden tified as a manufactured product fro m 
a softwood l og in a  sawmill, or in  a sawmill and  
planing mill. Such lumber, when rough, shall show saw or other primary manufac turing marks 
in the wood on the four longitudinal surfaces of each piece for its over -all length and shall not 
have been furth er manufactured  other than by 
crosscu tting, ripping , resawing, joining b y fin-
gerjointing, face -gluing  and/or edge -gluing , sur- 10 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 pr ovisions 
herein  is des ignated “Americ an Lumber Stand-
ard” (ALS) program l umber 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 Stand ard 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-
ation s (Appendix C);  and 
(e) Infor mation on implementat ion, and 
maintenance  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 compe tent 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 a n 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 andar d Commi ttee, Inc., its 
Board of Review, and its National Grading Rule C om-
mittee disclaim any liability for damages, includi ng 
consequential damages, in connection with the use or 
performance in use of p roducts pr oduced.  2.3 Certification --Procedure by which a 
third party gives written assurance that a pro d-
uct, process or service conforms to specified re-
quirements.  
 
2.4 Characteris tics--Distinguishing  fea-
tures which by the ir extent, loc ation, and numbe r 
determine the quality of a piece of lumber. The 
limiting characteristics of any grade of lumber d e-
scribed in certified grading rules shall be ex-
pressed within the terms of the definit ions in A p-
pendix B.  
 
2.5 Cubic measurement --The term used t o 
indicate that a cubic meter is the metric unit of 
measurement of lumber. The number of cubic m e-
ters in a piece of lumber is obtained by multiply-
ing the dressed thickness in millimeters by the 
dresse d width in millimeters  by the length in m e-
ters and  dividing the product by 1,000,000. [see 
Appendix B1]  
 
2.6 Design values--  Strength and sti ffness 
property values  of structural  lumber products 
published for design use .  These values are de-
termined for spe cific grades and spec ies/species 
groups and reflect the fact that wood is an ortho-
tropic material.  
 
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 nomi nal 5-inch or greater thick-
ness (timbers) is often manufactured and sol d 
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 lumb er grading rules certified 
by the Board, which for some species defines  dry 
lumber as having a maximum moisture content higher than 19 percent  [see 6. 2.6].  
  11 2.8 Grade marked (g rade stamped) --
Lumber that displays the official grading mark of 
an agency that  is made by rubber st amps, 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 mark s used in con nection  
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 lum ber was dry or 
green when manufactured  (but, see 6.2.6) ; and 5) 
the ap propriate 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 in form ation. 
 2.9 Grade – A minimum s tandard s pecifying 
the permitted characteristics of lumber, having 
regard to the end use for which the lumber is in-
tended . 
 
2.10 Grading agency-- An organization a c-
credited by  the Board that engages in the grading 
of lumber or that licenses and supervises  facilities 
that empl oy graders to grade and/or to place gra de 
marks up on lumber pro ducts.  
 2.11 Grading rules-- Requirements and 
specifications for the manufactur e, inspection  and 
grading of desig nated species of lumber. Lumber 
manufactured and graded acc ording 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.  
 
2.12 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 . 
 2.13 Heat treated (HT) -- Lumber or other 
wood products that have been heat ed in a cham-
ber, with o r without moisture content redu ction, 
until it achieves a minimum core temper ature of 
56
  °C for a min imum of 30 m inutes.  
 
2.14 Kiln dr ied (KD) -- Lum ber that has 
been seasoned in a chamber to a predetermined 
mois ture content by appl ying heat.  
 
2.15 Lumber -- Lumber is defined as a manu-
factured product deri ved from a log  through sa w-
ing or planing .  [see 3.3]  
  
2.16 Nominal size -- The label designa tion for 
lumber size categor ies that does not reflect the 
dressed size. The nominal size is gr eater than the 
dress ed size i.e ., a dry 2 by 4 is surfaced to 38 .1 
mm by 88.9 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 the formulation  of lumber grading rules 
and in the terms of purcha se 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 no minal size.  
 
3.2 Use 
 3.2.1  Yard lumber -- Lumber of those grades, 
sizes, and patterns intended for ordinary  con-
struction and building purposes  [see 6.3.1] . 
 3.2.2  Structural lumber -- Lum ber for use 
where d esign values are required  [see 6.3.2] .  12  
3.2.3  Factory and shop lumber -- Lumber 
that is produced or selected for remanufacturing 
purposes and intended for non -structural applic a-
tions  [see 6.3.3].  
 
3.3 Extent- of-manufacture  
 
3.3.1  Rough lum ber-- Lumber which has not 
been dressed (surfaced) but which has been 
sawed, edged and trimmed at least to the extent of showing saw or other primary manufacturing 
marks in the w ood on the four longitudinal su r-
faces of each piece for its  over-all length. L umber 
surfaced on o ne 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 pla ned on t he faces, fo r 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  labeled 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 edge (S1E), 
two edges (S2E), or a combination of sides and 
edges (S1S1E, S1S2E, S2S1E, S4S). Lumber sur-
faced S1E, S2E, S1S, S2S, S1S1E, S1S2E, S2S1E, 
S4S is classified as dressed (surfaced) lumber in 
the sur faced width or thicknes s. 
 
3.3.3  Worked lu mber-- Dressed lumber that 
has also been matched, shiplapped or patter ned. 
 
3.3.3.1  Matched (tongue -and-grooved, ce n-
termatch) lumber -- Lumber worked with a 
tongue on one edge of ea ch piece and a groove on the opposite edge to provide a close tongue -and-
groove joint by fitting  two pieces together; when 
end-matched, the tongue  and groove are worked 
in the ends also.  
 
3.3.3.2  Shiplapped lumber -- Lumber worked 
or ra bbeted on both edges of each piece to provide 
a close- lapped joint by fitting two  pieces together . 
 
3.3.3.3  Patterned  lumber-- Lumber shaped to 
a pat tern or to a molde d form, in addition to being 
dressed, matched, or shiplapped, or any combin a-
tion of these workings.  
 3.4 Nominal  size  
 3.4.1  Boards -- Lumber of less than nominal 2-
inch thickness and of  nominal 2- inch or g reater  
width. Lumber of less than nominal 2- inch t hick-
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 no minal 2 -inch o r grea ter width.  D i-
mension is also designated as framin g, 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, 
girder s, or purlins.  
 
3.4.4 The dr essed sizes of all lumber dimen-
sions refer enced in this Standard in terms of 
"nominal" sizes are set -out in Tables 1 through 4. 
The use of "nominal" sizes in  the language of this 
Standard follows the practice of the industry. No  
inferences 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  13 sizes shall be used when lumber is measured by 
cubic measur e. 
Note: The i nvoic es for dressed  lumber of standard 
sizes should sho w 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 sha ll be tallied board 
measure as of e ither the rough or the nominal size  
that was used in its manufacture. Cubic measure 
of lumber shall also be permitted. Dressed sizes 
shall be used when lumber is mea sured by cubic 
measure.  
Note: The dressed th ickness and width of such 
lumber  should be shown on the invoice.  
 4.3 Board rule t ally— In lumber specified 
to be mea sured with a board rule on dressed 
widths, pieces measuring to the even half foot are 
alternately counted as of the next higher and low-
er foot count; f ractions below the half foot  are 
dropped, and fractions above the half  foot are 
counted as of the next higher foot.  
 4.4 Averages
3--length, width -- The aver-
age length in feet of a shipment of lumber is com-
puted by dividing the total length in feet by the 
total number of p ieces in the shipment. The aver-
age width in inches of a shipment of lumber of 
nominal 1 inch or less thickness is computed by 
dividing the total board feet by the total length in 
feet and multiplying the results by 12; but if the  
pieces are thicker than no minal 1 inch,  the total 
board foot tally is divided first by the nominal thickness as expressed in inches and fractions of an inch.  
 
5.  LUMBER SIZES  
 
5.1 Rough size -- The minimum rough 
thickness 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 
 
3 This computation applies to c onven tional units.  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 dressed thi ckness. 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 Table s 1, 2, 3 and 4 
pertain to thos e items as measured at time of 
manufact ure. Lumber will change in dimension 
(shrink or expand) in response to its equilib rium 
moisture content  [see 6.2.3.1 and 6.2.5.1] . [See al-
so 5.3.1 covering length and 7.3 for 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 purch ase, lumber shall be  trimmed 
for the removal of spur and splintered en ds, 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). 
 
Note:  The marketin g practice covering lengths of 
lumber should permit the buy er to o btain specified 
lengths or specif ied assortments of lengths.  
  14 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 a pply to all thickne sses except a s modified. Sizes are 
given in millim eters and inches. Metric units are based on dressed size. See B1, A ppendix B for rounding 
rule for metric units . 
 
Item  Thicknesses  Widths  
Nominal  
Inch  Minimum Dressed  Nominal  
Inch Minimum Dressed  
mm inch mm inch 
Finish  3/8 
1/2 
5/8 3/4 
1 
1-1/4 
1-1/2 
1-3/4 
2 
2-1/2 
3 
3-1/2 
4 8 
11 14 16 
19 
25 
32 
35 
38 
51 64 76 
89 5/16 
7/16 9/16 
5/8 
3/4 
1 
1-1/4 
1-3/8 
1-1/2 
2 
2-1/2 
3 
3-1/2 2 
3 
4 
5 
6 
7 
8 
9 
10 
11 12 14 
16 38 
64 89 
114 
140 
165 
184 
210 
235 
260 
286 337 
387 1-1/2 
2-1/2 
3-1/2 
4-1/2 
5-1/2 
6-1/2 
7-1/4 
8-1/4 
9-1/4 
10-1/4 
11-1/4 
13-1/4 
15-1/4 
Flooring a 3/8 
1/2 5/8 
1 
1-1/4 
1-1/2 8 
11 14 
19 
25 
32 5/16 
7/16 9/16 
3/4 
1 
1-1/4 2 
3 
4 
5 
6 29 
54 79 
105 130 1-1/8 
2-1/8 
3-1/8 
4-1/8 
5-1/8 
Ceiling a 3/8 
1/2 5/8 
3/4 8 
11 14 
17 5/16 
7/16 9/16 
11/16  3 
4 
5 
6 54 
79 
105 
130 2-1/8 
3-1/8 
4-1/8 
5-1/8 
Partition a 1 18 23/32 3 
4 
5 
6 54 
79 
105 
130 2-1/8 
3-1/8 
4-1/8 
5-1/8 
Stepping  1 
1-1/4 
1-1/2 
2 19 
25 32 
38 3/4 
1 
1-1/4 
1-1/2 8 
10 12 184 
235 286 7-1/4 
9-1/4 
11-1/4 
 
a In tongued -and-grooved flooring  and in tongued -and-grooved and shi plapped ceiling of 8 mm (5/16 inch), 11 mm (7/16 
inch), and 14 mm (9/16 inch)  dressed thicknesses, the tongue or lap shall be 5 mm (3/16 inch) wide, with the over- all 
widths 5 mm (3 /16 inch)  wider than the face widths 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 lumber,  and th e lap shall be 10 m m (3/8 inch)  wide or wider in shiplapped 
lumber, an d 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.   15 Table 2. Nominal and minimum -dressed dry sizes of sidi ng at 19 percent ma ximum-
moistu re content.  
 
The thicknesses apply to a ll 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 unit s. 
 
Item  Thicknesse s Widths  
Nominal  
Inch  Minimum Dressed  Nominal  
Inch Minimum Dressed  
mm inch mm inch  
Plain Bevel  1/2 
9/16 
5/8 
3/4 
1 
  11 butt, 5 tip  
12 butt, 5 tip  
14 butt, 5 tip  
17 butt, 5 tip  
19 butt, 5 tip  
 7/16 butt, 3/16 tip  
15/32 butt , 3/16 t ip 
9/16 butt, 3/16 tip 
11/16 b utt, 3 /16 tip  
3/4 butt, 3/16 tip  4 
5 
6 
8 
10 
12 89 
114 
140 
184 
235 
286 3-1/2 
4-1/2 
5-1/2 
7-1/4 
9-1/4 
11-1/4 
Rabbeted 
Bevel  1/2 
3/4 11 butt, 5 tip  
17 butt, 7 t ip 7/16 butt, 3/16 tip  
11/16 butt, 9/32 tip  4 
6 
8 
10 
12 89 
140 
184 
235 
286 3-1/2 
5-1/2 
7-1/4 
9-1/4 
11-1/4 
Bungalow  3/4 17 butt, 5 tip  11/16 butt, 3/16 tip  6 
8 
10 12 140 
184 
235 
286 5-1/2 
7-1/4 
9-1/4 
11-1/4 
Shiplap (10 
mm (3/8 in.) 
lap)b 5/8 
1 14 
18 a  9/16 
23/32 a  4 
5 
6 
8 
10 
12 76 
102 
127 
171 
222 
273 3 
4 
5 
6-3/4 
8-3/4 
10-3/4 
Shiplap   ( 13 
mm (1/2  in.) 
lap)b 5/8 
1 
2 14 
18 a 
38 9/16 
23/32 a  
1-1/2 4 
5 
6 
8 
10 
12 73 
98 
124 
168 
219 
270 2-7/8 
3-7/8 
4-7/8 
6-5/8 
8-5/8 
10-5/8 
Dressed and Matched (Tongue and 
Grooved, 6 
mm (1/4 in.) 
tongue)
b 5/8 
1 14 
18 a   9/16 
23/32 a  4 
5 
6 
8 
10 
12 79 
105 
130 
175 
225 
276 3-1/8 
4-1/8 
5-1/8 
6-7/8 
8-7/8 
10-7/8 
Dressed and 
Matched 
(Tongue and 
Grooved, 10 
mm (3/8 in.) 
tongue)b 1 18 a 23/32 a 4 
6 
8 
10 
12 76 
127 
171 
222 
273 3 
5 
6-3/4 
8-3/4 
10-3/4 
 
a Minimum dressed thickness for 1 -inch nom inal re dwood and western r ed cedar shi plap a nd tongue and groove siding 
patte rns 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 s hall 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.    16 Table 3. Nominal and minimum -dresse d sizes of boards, dimension, a nd timbers.  
 
The thicknesses apply to a ll 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 unit s. 
 
Item  Thicknesse s Widths  
Nominal  
Inch  Minimum Dressed  Nominal  
Inch Minimum Dres sed 
Dry a Green a,b Dry a Green a,b 
mm inch  mm Inch mm inch  mm inch  
Boards  3/8 
1/2 
5/8 
3/4 
1 
1-1/4 
1-1/2 8 
11 
14 
16 
19 25 
32 5/16 
7/16 
9/16 
5/8 
3/4 
1 
1-1/4 9 
12 
15 
17 
20 26 
33 11/32  
15/32  
19/32  
11/16  
25/32  
1-1/32 
1-9/32 2 
3 
4 
5 
6 
7 
8 
9 
10 
11 
12 
14 
16 38 64 
89 
114 
140 
165 
184 
210 
235 
260 
286 
337 
387 1-1/2 
2-1/2 
3-1/2 
4-1/2 
5-1/2 
6-1/2 
7-1/4 
8-1/4 
9-1/4 
10-1/4 
11-1/4 
13-1/4 
15-1/4 40 
65 90 
117 
143 
168 
190 
216 
241 
267 
292 
343 
394 1-9/16 
2-9/16 
3-9/16 
4-5/8 
5-5/8 
6-5/8 
7-1/2 
8-1/2 
9-1/2 
10-1/2 
11-1/2 
13-1/2 
15-1/2 
Dimension  2 
2-1/2 
3 
3-1/2 
4 
4-1/2 38 
51 
64 
76 89 
102 1-1/2 
2 
2-1/2 
3 
3-1/2 
4 40 
52 
65 
78 
90 
103 1-9/16 
2-1/16 
2-9/16 
3-1/16 
3-9/16 
4-1/16 2 
2 1/2  
3 
3 1/2  
4 
4 1/2 
5 
6 
8 
10 12 
14 16 38 
51 
64 76 89 
102 
114 
140 
184 
235 
286 
337 
387 1-1/2 
2 
2-1/2 
3 
3-1/2 
4 
4-1/2 
5-1/2 
7-1/4 
9-1/4 
11-1/4 
13-1/4 
15-1/4 40 
52 
65 
78 90 
103 
117 
143 
190 
241 
292 
343 
394 1-9/16 
2-1/16 
2-9/16 
3-1/16 
3-9/16 
4-1/16 
4-5/8 
5-5/8 
7-1/2 
9-1/2 
11-1/2 
13-1/2 
15-1/2 
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 gr een lumber. 
 
 b except for minimum dressed gree n sizes for Redwood, Western Red Cedar, and Northern Wh ite Cedar  [see section 6.2.5 ]. 
  17 Table 4. Nominal and minimum -dressed sizes of wo rked lumber.  
 
The thic knesses 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 D ressed  Nom inal 
Inch  Minimum Dressed  
Drya Greena,b Drya Greena,b 
mm inch  mm inch  mm inch  mm inch  
Shiplap,  
10 mm (3/8 inch)  
lapb 1 19d 3/4d 20 25/32 4 
6 
8 
10 12 14 
16 79 
130 175 
225 
276 327 
378 3-1/8 
5-1/8 
6-7/8 
8-7/8 
10-7/8 
12-7/8 
14-7/8 81 
133 181 
232 
283 333 
384 3-3/16 
5-1/4 
7-1/8 
9-1/8 
11-1/8 
13-1/8 
15-1/8 
Shiplap,  
13 mm (1/2 inch) 
lap c,d 1 
2 
2-1/2 
3 
3-1/2 
4 
4-1/2 19d 
38 51 64 
76 
89 
102 3/4d 
1-1/2 
2 
2-1/2 
3 
3-1/2 
4 20 
40 
52 65 
78 
90 
103 25/32  
1-9/16 
2-1/16 
2-9/16 
3-1/16 
3-9/16 
4-1/16 4 
6 
8 
10 
12 
14 
16 76 
127 
171 222 
273 
324 
375 3 
5 
6-3/4 
8-3/4 
10-3/4 
12-3/4 
14-3/4 78 
130 
178 229 
279 
330 
381 3-1/16 
5-1/8 
7 
9 
11 
13 
15 
Cent ermatch 
(Ton gue & 
Groove),  
6 mm (1/4 inch) 
tonguec 1 
1-1/4 
1-1/2 19d 
25 
32 3/4e 
1 
1-1/4 20 26 33 25/32 
1-1/32 
1-9/32 4 
5 
6 
8 
10 
12 79 
105 130 
175 
225 
276 3-1/8 
4-1/8 
5-1/8 
6-7/8 
8-7/8 
10-7/8 81 
108 133 
181 
232 
283 3-3/16 
4-1/4 
5-1/4 
7-1/8 
9-1/8 
11-1/8 
Centermatch 
(Tongue & 
Groove),  
10 mm (3/8 inch) 
tongue d 2 
2-1/2 
3 
3-1/2 
4 
4-1/2 38 
51 
64 
76 89 
102 1-1/2 
2 
2-1/2 
3 
3-1/2 
4 40 
52 
65 
78 90 
103 1-9/16 
2-1/16 
2-9/16 
3-1/16 
3-9/16 
4-1/16 4 
6 
8 
10 12 76 
127 
171 
222 273 3 
5 
6-3/4 
8-3/4 
10-3/4 78 
130 
178 
229 279 3-1/16 
5-1/8 
7 
9 
11 
Grooved -for-
Splines  2-1/2 
3 
3-1/2 
4 
4-1/2 51 
64 76 
89 
102 2 
2-1/2 
3 
3-1/2 
4 52 
65 
78 
90 
103 2-1/16 
2-9/16 
3-1/16 
3-9/16 
4-1/16 4 
6 
8 
10 
12 89 
140 
184 
235 
286 3-1/2 
5-1/2 
7-1/4 
9-1/4 
11-1/4 90 
143 
190 
241 
292 3-9/16 
5-5/8 
7-1/2 
9-1/2 
11-1/2 
 
a  See 2.7 and 2.11 for the definitions of dry and green lumber.  
b except for minimum dressed gree n sizes for Redwood, W estern Red Cedar, and Northern Wh ite Cedar  [see sec tion 6.2.5] . 
 
c  In worked lumber less than no minal 2 -inch thickness, the tongue shall be 6 mm (1/4 inch) wide in tongued and grooved lumber and 
the lap shall be 10 mm (3/8 inch) or 13 m m (1/2 inch)  wide i n shiplapped 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.  
 
dIn worked lumber of nominal 2 -inch and greater thick ness, the tong ue shall be 10 mm ( 3/8 inch) wide in tongued -and-grooved lu m-
ber and th e 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 tabl e.  Double tongued -and-grooved decking shall be manufa c-
tured with a 1 0 mm (3/8 inch) or 8 mm (5/16 inch) wide tongu e.  
 
e  Alternate minimum dressed dry thickness for 1- inch nominal center -match and shiplap is 18 mm (23/32 inch).   18 6.  GRADI NG RULE REQUIRE MENTS  
 
6.1 General concepts  
 
6.1.1  Grading parameters -- To the extent to 
which di fferences in the characteristics of species, 
in the quality of logs, in conditions  of manufacture 
and in the uses to which the product is put will 
permit, the ba sic provisions  for the gra ding of  
lumber shall be uniform. The grading of lumber cannot be considered an exact science because it is based on either a visual inspection of each piece 
and the judgm ent of the grader or on the results 
of a method of mechanica lly determinin g the 
streng th char acteristics 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 us e classifications, the grade 
provisions shall satis fy the r equirements for both 
classifications.  
 
6.1.2  Minimum grade requirements--  The 
method o f determining the extent 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 g rade 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 --  Characteris-
tics permi tted and limitations for  rough lumbe r 
shall be the  same as tho se prescribed in grading 
rules for dressed lumber of the same grade and, in 
addition, such others as will disappear in stand-
ard dressing sh all be allowed. If charac teristics 
other than those described in certified grading 
rules a re encountered,  they shall be evaluated in 
relation to the characteris tics permitted or limita-
tions pr escribed for the grade under consideration and shall be allowed if r egarded as equi valent or 
less damaging in effect on the strength, appear-
ance, or other  utility value of t he piece. In all 
grades, the size of allowable char acteristics shall 
not exceed that specified in the respec tive grading 
rules.  
 Note:  In many grades, the size of permitted char-
acteri stics varies in proportion to the size of a face 
or the area of a cross section of the piece.   
 
6.1.4  Special provisions -- When heartwood, 
sapwood, grain classifications, and other optional 
provisions are specified, and  the lumber conform s 
to the requirements of such special provisions as 
well as to the reg ular grade desig nated, it sh all be  
regarded as of standard quality.  
 
6.1.5 Mixed grades -- Mixed grades other 
than the two highest established grades for each 
grading ru le category shall n ot be included in cer-
tified grading rules.  
 
6.1.6  Nonstandar d grades -- When non-
stand ard grades, siz es, or patterns are specified, 
or when p articular provisions of a standard grade 
are waived or changed, inspection shall be made 
accordingl y, but all of the other 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 devel-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 ex-
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 S tandardization 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  19 appropriate . The restrictions on the moisture co n-
tent of seasoned lumber shall apply at the t ime of 
shipment, a t the time o f dressing (if dressed lu m-
ber is involv ed), and at the time of any reinspec-
tion (if moisture content is involved in the rein-
spection), as p rovided in the appl icable grading 
rules.   Any piece exceeding the allowable moisture 
content of the appli cable grade provisions shall be 
considered out of c ompliance.  
 6.2.2  Grading rules-- The grading rules for 
each species or region shall include clear defin i-
tions for dry lumber under nominal 5- inch thic k-
ness [see 2.7]. The definitions sh all 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 2.12 ]. 
 
6.2.3  Dry size  requirements-- The grading 
rules shal l 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 p ercent moisture content, or 
at such lower maximum -moisture content as may 
be applicable to the lumber at the time of dres s-
ing. The minimum -dressed dry si zes are shown in 
tables 1, 2, 3 and 4.  
 6.2.3.1   Shrinkage or expansion from dr y 
size– Shrinkage or exp ansion that o ccurs after 
dressing to standard dry s ize 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 m oisture content cha nge or 
0.7 pe rcent 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-pans ion of individual p ieces 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 mo isture 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 ickne ss and 
width, as se t forth in t ables 3 and 4.  
 6.2.5  Green size requir ements -- The mini-
mum dressed green sizes specifically stated in the rules shall be not less than the gr een sizes
5 shown 
in tables 3 and 4, except for Redwood, Western 
Red Cedar, and Nort hern White Cedar. F or these 
three species, the following minimum dress ed 
green thicknesses shall apply: 17 mm (21/32 inch) 
for corresponding nominal 3/4  inch dry, 20 mm 
(25/32 inch) for nominal 1- inch, 40 mm (1- 9/16 
inch) for nominal 2 -inch, 52 mm (2- 1/16 inch) for 
nominal 2-1/2 inch, 65 mm (2 -9/16 inch) for nom i-
nal 3- inch,  78 mm (3- 1/16 inch) for nominal 3- 1/2 
inch, 90 mm (3- 9/16 inch) for nominal 4 -inch, and 
103 mm (4- 1/16 inch) for nominal 4 -1/2 inch. The 
following minimum green dressed widths shall apply: 65 mm (2- 9/16 i nch) 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 charac-
teristics.   See Fores t Produ cts Laboratory Research 
Reports 15 and 30.  
5 The minimum green s izes 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 maxi-
mum moisture content with recognition  given to ma nu-
facturing practices and the differences  in shrinkage 
characterist ics between species of lumber or species 
groups o f lumber.   20 187 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 t olerance below  minimum 
standard green sizes on a ba sis of 1 percent 
shrinkage for each four percentage points of moisture content below 30 percent or 0.7  percent 
shrinkage for each four percentage points of 
moisture content below 30  percent for Redwood, 
Western Red Ceda r, and Northern White Cedar. 
Expansio n allowances are deter mined assuming 
a typical equilibrium moisture content or other 
suitable referenc e moisture content.  The shrink-
age or expansion percentages are average values. 
Shrink age 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 gree n 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 pe rcent 
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 af-
fect m easur ement a nd shrinkage of lumber are: density, 
species, grain orientation and allowable grade chara c-
teristics.  See Forest Products Laboratory Research R e-
ports 15 and 30.  6.3 Use classification provisions for vi s-
ual grad ing 
 
6.3.1  Yard lumber  
 
6.3.1.1  Grade classifications -- The grading of 
surfaced yard lumber is based upon the uses for 
which t he particular grade is designed and is a p-
plied to each kind with reference to its s ize and 
length when graded without consideration to  fur-
ther manufacture. On the basis of quality, the 
basic grade classifications of yard lumber shall be 
as follows:  
 (a)  S elect: Lumber for natural and paint fi n-
ishes.   
 (b)  Common: Lum ber for general con struc-
tion and utility purposes.  
 
6.3.1.2  Yard lumber sizes -- The dressed thick-
nesses and widths of yard lumber as specified in 
3.4, 5.1 and 5.2 shall be considered  as minimum 
standar ds for the corre sponding nominal sizes as 
shown.  
 
Note: Lumb er of standard size, rough  or dressed,  
may be described by its nominal di mension 
providing dressed sizes are shown on invoices and 
other documents.  
 
6.3.1.3  Bundled lumber -- Each  length of bun-
dled lumber, except end -matched lumber, beveled 
siding, and bungalow  siding shall be 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 the buyer, be rejected or be 
accepted as of the  next lower grade.  
 
6.3.1.5  Grading faces -- Yard lumber other 
than timbers and dimension [see 6.3.2.3] shal l be 
graded from th e face or best side only unless ot h-
erwise specified.  
  21 6.3.1.6  Fencin g – Sawn boards use d 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 ex-
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. Fore st 
Prod ucts Laborat ory, shall be the final authorit y 
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 cer-
tification, the Board shall obtain a report from the 
Laboratory evaluating whether  the procedures 
used in developing the claimed va lues are in a c-
cordance with the standards and criteria de-
scribed herein. Rules -writing  agencies 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-
sponsibility for writing grading rules for a given 
species, a group of  species, or a geog raphica l sub-
division of a species or of a group of species, a common set of strength and stiffness values shall 
be used by the agencies involved for that spec ies, 
subdivision, or group of species in the interest of 
uniformity and sta ndardization.  
 6.3.2.2  Grading --mechanical --The grading of 
structural lumb er by mechanical means is reco g-
nized as an acceptable method of grading.  When graded by mechanical means all such grading 
equipment and methods shall be subject to ap-
proval and certifica tion 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 formula te and 
publish grad ing rules and which have been ce rti-
fied by the Board.  
 
6.3.3.2  Grade characteristics --Factory and 
shop lumber shall be graded with referenc e to its 
use for doors and sashes, or on the basis of chara c-
teristics affecting  its use for genera l cutup  pur-
poses, or on the basis of size of cuttin g. 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 ba sed 
on the qual ity of both sides of each cutting.  
 
6.3.3.3  Grade sizes -- The ALS program grade 
sizes for factory and shop lumber shall be those promulgated by  the agencies which  formulate and 
publish grading rules and which have been cer ti-
fied by the Board . 
 6.3.3.4 Warped lumber --The cuttings in 
warped lu mber 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  accredited 
agency shall submit procedures with res pect to 
grade marking to the Board for approval.  
 
7.2 Agency symbol --Each accredited age n-
cy shall maintain a bona fide supervi sory inspec-
tion service under which each mill authorized to 
use the registered symbol of the accre dited age n-
cy
7 in conjunction wit h the grade mark will be in-
 
7 Facsimiles of the grade marks o f the grading and inspe c-
tion agencies that are acc redit ed by t he Board of the 
ALSC, Incorporated, are a vailable on the web at  22 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 gra de 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 
provisions of the rules under which it is graded. 
When green lumber o f 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 gr ading 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, purch asers a nd consumers .
8 
 7.3.3  All pieces and/or bund les 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 
pack age. 
 
 
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 the two highest 
recognized grades for each grading rule catego ry, 
shall not be gr ade 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 the species [see Appendix A] from which 
the lumber was produced. The identificati on of 
species shall not be  required wh en the agency 
symbol also indica tes 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 o f this section are  ob-
served.  
 
7.3.7  Remanufacture ( ripping , resawing or 
surfacing ) of graded or grade marked lumber n e-
gates the grade or grade mark and the design va l-
ues of the orig inal pro duct and the original grade 
mark shall be removed, by any appropriate 
means. 
 
7.3.7.1  When  grade marked dimen sion lumber is 
resawn or remanuf actured in such a way as to p o-
tentially alter the grade indicated by the grade 
mark, the original grade mark shall be oblitera t-
ed. 
 
8.  INSPECTION AND REINSPECTION  
 
8.1 Inspection  
 
8.1.1  Agency certificati on and superv i-
sion- -When ALS program lumber is grade  23 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 upervision.  
 
8.1.2  Delegation of grading authority--
Permission to grade mark shall be delegated only 
by an agency accre dited by the Board to operate a 
mill supervisory service to those mills which have 
demonstrated and proven their ability  to conform 
to and are cur rently in conformance 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 and 
grade and to submit its lumber to inspection by the superv isory agency both at the mill and upon 
complaint at destination.  
 8.1.3 Payment--certificate costs -- When an 
accredited agency issues a certificate on a shi p-
ment, the party reque sting the certifica te shall 
pay for the cost thereof.  
 
8.1.4  Service -- Inspecti on service shall b e re-
quire d for the in spection of grades not describ ed 
in the rules only when written detailed specific a-
tions accompany the re quest for such inspection. 
For the inspection of stand ard grades in no n-
standard sizes, inspection service shall b e re-
quired based o n 6.1.6 unless 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 A LS program grades of lumber shall be 
construed as involving agreement  to submit lu m-
ber to reinspection by an accredited inspection 
agency under published rules by which the lum-
ber was graded [see 8. 2.4]. Grading rules shall i n-
clude provisions for reinspec tion in case of com-
plaint, and reinspecti on shall be available to any-
one at reaso nable cost.   
8.2.2  Complaints -- Grade complaints on lu m-
ber shall be recognized only when the  lumber is in 
the form in w hich it was shipped. Any subs equent 
change in manufactur e, working, or through kiln -
drying shall r elieve the seller of respons ibility 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 mois-
ture co ntent specified an d shall hold  intact that  
portion which is disputed for inspection or rein-
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 n ot be construed as the acceptan ce 
of the en tire shipment. The buyer sh all hold the 
disputed lu mber intact, properly protected, for not 
more than 30 days after the date of the request  for 
inspection or reinspection. The buyer shall file a 
complaint with the  seller within the time 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 specificat ions of 
the grade, size,  or moisture con tent.  
 8.2.4 Seller's responsibilities- - Upon receipt 
of a co mplaint from the purchaser, the seller shall 
immediately reques t the agency under whose 
rules shipment has been made, or such other 
agen cy tha t was agreed upon, to prov ide inspec-
tion, reinspection or retally as required ac cording 
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 sha ll be 
borne in acco rdance with the inspection  provisions 
of the applic able grading rules, but the person 
calling for the reinspection shall be responsible to the agency for the costs thereof. The purchas er 
shall lend all reasonable assistance to facilitate 
the in spection, re inspection or retally.   24  
8.2.6 Tally, grade, and siz e complaints -- In 
case of a complaint involving tally, the entire item 
shall be held intact for retally. In case of  a com-
plaint regarding grade or size, but not involving 
tally, the buye r shall hold intact  that portion o f 
the item t hat is of the grade or s ize 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 compl aint invo lving mois ture content, 
the 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 com plaint o n moisture  con-
tent shall be 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 fr om any 
portion ex ceeding 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 
moist ure 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 a nd shall be 
the property of the seller unless otherwise agreed. 
These  provisions shall not apply in the case of 
specially worked lumber.  
 
9.  AMERICAN LUMBER STANDARD 
COMMITTEE  
 9.1 Func tions of ALSC -- The functions of 
the ALSC shall be:  
 9.1.1  To act as the St anding 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 U .S. Department of Commerce s hall be 
appli cable.  The Department of C ommerce shall 
provide the secre tariat 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 continu-
ously available basic standards for l umber 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 adequa-
cy of the facilities p rovided by agencies pu blishing 
grading rules for the purpose of lumber certifica-
tion, inspection, reinspection, and supervision of grade ma rking.  
 
9.1.3.3  The competency, reliability, an d adequa-
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 
interpre tation or application  of this Standard  and 
the detailed requirements  defined and establ ished 
by the ALSC.  
 9.1.5  To fix , after consultatio n 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 co ntingencies, of car rying out 
its functi ons, those o f the Board, and th e NGRC. 
Such charges and fees shall be assessed at a uni-form proportionate rate against the agencies pa r- 25 ticipating in th e use of the facilities of the ALSC. 
The accreditation of any agenc y 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 nci-
pal and alternate members s hall be appointed b y 
the Secretary of Commerce for terms of not less  
than two nor more than five years.  
 9.3 Composition of ALSC -- The following 
procedures shall apply in making appointments to 
the ALSC.  
 
9.3.1  A rules -writing agency is one that parti c-
ipate s in this program a nd that formulates, pu b-
lishes, and maintains grad ing 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  
 Allott ed 
Southern Pine Inspection Bureau  2 
Western Wood Products Association  2 
Pacific Lumber Inspection Bureau  2 
Redwood Inspection Service 1 
Northeastern Lumber Manuf acturers  
Association  2 
National Lumber Grad es Authority  1 
Each other agency qualifying under  
this category  1 
 
9.3.2  A non -rules writing agency ( NRWA) is 
an agency that participates in this program 
and that does not publish grading rules. In the 
event that there are three or more N RWAs 
participating in this program, each NRWA may nominate one principal and alternate member and three principal membe rs and 
their alternates shall be appointed from among the nominees so furnished. In the event that there are only two NRWAs participatin g in the 
program, each NRWA may nominate a princi-
pal and alternate member and, in addition, the 
two existing NRWAs may together nominate a 
third principal and alternate member, and three principal members and their alternates 
shall be appointed from among t he nominees 
so furnished. In the event that there is only one NRWA participating in the program, the 
single NRWA may no minate up to two princi-
pal members and two alternates, and two prin-
cipal members and their alternates shall be 
appointed from the nomine es so furnished.
 
 
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 
Enginee rs 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 submitte d to 
the Secretary of Commerce by the appropriate 
agency, firm, or organization upon req uest or 
whenever a vacancy occurs in the segment repr e-
sented. Ea ch nomination shall contai n the follo w-
ing: 
  26 9.3.5.1  A summary of the qualifications of the 
nominee. 
 
9.3.5.2  A statement of the method or procedure 
by whic h the nominee was selected and the pr oce-
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 ag encies or 
segments of the industry ot her 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 Secre-tary of Commerce from t he followin g Federal 
agencies:  
 
 Department of Defense  
 Department of Agriculture 
 Departm ent of Interior  
 General S ervices Administration  
 Department of Housing &  Urban Develop ment 
 National Institute of Standards &  Techno logy  
 9.3.7  Balance of represen tation  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 si ngle interest category. In such 
consi derations,  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 i n 10.3, shall serve 
as the Secretary of the ALSC.  
 9.5 Transaction of business  
9.5.1  Meetings --A majority of the members of 
the ALSC representing agencies which formulate, 
publish, and maintain grading rules and mainta in 
inspection facilities, together wit h 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  pre-
sent,  a majority of those present shall adjourn the 
meet ing or act on the subjects b efore it, subject to 
ratification in w riting by the respective m ajorities 
which constitute a quo rum.  
 
9.5.2  Correspondence -- Busin ess that has 
not been previously pres ented at a meeting of the 
ALSC shall be held until the next meeting or 
transacted by corre spondence 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 und er 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 me mbers, 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 three membe rship 
groups within the ALSC that shall eac h nominate 
one potential member of the Board. The s poke s-
person shall determine and repor t 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:  
  27 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 member s representing the accredited non -
rules -writing lum ber inspection agencies.  
 
10.2.1.3  One member  by majority decision of 
those remaining ALSC member s representing 
other inter ests. 
 
10.2.1.4  The name of the nominee  shall be sub-
mitted to the Department of Co mmerce prior to 
election and shall be accomp anied b y a summary 
of the qualifications of t he 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 desig-
nated under 10.2.1.1, 10.2.1. 2 or 10. 2.1.3 fails to 
receive a m ajority of the votes cast at any election, 
a new no minee shall be designated in  accordance 
with the procedure set forth in 10.2.1.1, 10.2.1.2  
or 10.2.1.3.  
 
10.2.3  Terms --The three membe rs of the Board 
shall be elected for t erms, 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 d eath, re signation, or r e-
moval shall be filled at any regular ly called com-
mittee meetin g subject to the provisions  of 10.2.1, 
10.2.2 and 9.5.2. Any person elected to fil l a va-
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 ex-
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 a ll 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 exec utive 
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 in spection agency while employed by the 
Board.  
 10.4 Certification functions--Upon applic a-
tion, th e Board shall examine and certify the fol-
lowing as c onforming to the requiremen ts of this 
Standard and to  additional detailed requirements 
established by the AL SC: Grade strength ratios, 
nomenclature, descriptio ns of grades published by 
the NGRC an d 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 fully and fairly avail a-
ble to all manufacturers, distri butors, and co n-
sumers of such lumber, on equal terms and condi-
tions without discrimination). Certification  shall 
be subject to these conditions : 
 
10.4.1 Rules conform to the basic requirements 
of this St andard.  
 
10.4.2  Published rules carry specific refer ences 
to such  certification.  
 10.4.3 The originating age ncy 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-
crimi natio n. 
  28 10.4.4 Subsequent revis ions made by  the pro m-
ulgating agency to grading rules t hat have been 
certified by the Board shall be acted  upon within 
90 days after sub mission  to the Board.  
 
10.4.5 Grading rules of an agency shall not be 
certified as conforming  to this Standard if the 
Board determin es the dimension lumber rules 
therein fail to conform to the provisions of the N a-
tional Gradin g Rule for dimension lumber esta b-
lished pursu ant to Section 11 of this Standard.  
 
10.5 Accreditation 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 o f this 
Standard and to additional req uirement s esta b-
lished by the ALSC. Accreditation shall be su bject 
to these conditions:  
 
10.5.1 The competency, re liability, a nd adequa-
cy of the facilities provided by a gencies participa t-
ing in this program for the purpo ses of lumber 
certification, inspecti on, 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 gr ading 
rules to this Standard.  
 10.5.4 The con tinuing competency and adequa-
cy of performance of ag encies.  
 
10.6 Withdrawal of  accreditation --If at 
any time the pra ctices of any accredited agency 
are found not in conformity with this Standard 
and other requi rements adopted by the ALSC, 
and if, a fter du e notice in writing to that effect, 
according to established procedures, those  prac-
tices shall not have b een brought into conformity 
with such standards and oth er requirements by 
the agency concerned, the Board is empowered to revoke all previous a ccredita tion granted that 
agency.  
 
10.7 Actions of Board --In all actions in rela-
tion t o the certification of grad ing rules, a ccredit a-
tion of agencies and inspection fac ilities, and 
grade marking practices, the Board sha ll proceed 
in a fair and nondiscrimina tory ma nner giving 
full and due consideration to the past e xperience 
and performance o f agencies seeking accredit a-
tion, and shall apply uniform standards of jud g-
ment i n 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 accreditati on from the Board. No inspe c-
tion agen cy 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 buy ers and users for i n-
spection of their own purchases  shall not be ac-
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 party. The Board's facilities 
shall also be av ailable to all lumber inspection 
agencies, without favor or discrimination and 
without an y 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 jurisdi ction of the Board.  
 10.9 Enforcement --The Bo ard shall adopt, 
subject to prior approval by the AL SC, and admi n-
ister rules, r egulations, and sanctions to ensure 
the continued competency, reliability, and in tegri-
ty of accredited agencies providing inspection  ser-
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  29 which suc h party may appear personally or be 
represe nted by counsel to present supporting ev i-
dence and argument of the party's position in a c-
cordance with procedures established by the 
Board.  
 10.11  Reports of action --The Boar d shall 
within 30 days foll owing an off icial action make 
such off icial action publ ic. 
 11.  NATIONAL GRADING RULE COMMITTEE  
 
11.1 Autonomy of NGRC --The National 
Grading R ule Comm ittee (NGRC) shall be an a u-
tonomous body functioning  under by -laws (provid-
ing, among other things, for th e appointmen t of 
subcommittees) approved by the ALSC. T he by-
laws shall be reviewed at least every 5 years and 
reaffirmed or revised, as appropri ate. 
 11.2 Functions of the NGRC --The NGRC 
shall establish,  maintain, and make fully a nd fai r-
ly available grade -strength ratios, nomencla ture, 
and descriptions of grades for dimension lumber conforming to this Standard. Grading rules of an agency shall no t 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 t his se c-
tion. 
 
11.3 Composition of NGR C--In the interest 
of obtaining balanced views, the NGRC shall be 
composed of persons r epresenting the following 
that desire to partici pate:  
 
 Organization  Number of  
  Mem bers 
 Southern Pine Inspection Bureau  2 
 Western  Wood Products Association  2 
 Pacific  Lumber Inspection Bureau  2 
 Redwood Inspection Ser vice 1 
 Northeastern Lumber  Manufacture rs Association, Inc.  2 
 
 International Code Council 1 
 National Fire Protection Association  1 
 National Association of Home Build ers 1 
 National Lumber Grades Authori ty  1 
 American  Society of C ivil Engineers  1 
 American Institute of Architects  1 
 Consumer s 1 
 Lumber Wholesalers  1 
 Lumber Retailers  1 
 U.S. Non -rules W riting Agencies  2 
 Ex officio, non -voting members shall be appoint ed 
from the following Federal agencies  that desire to 
participate:  
 
 Department of Housing and Urban 
  Develop ment  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 c om-
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 repre-sentation shall appoint a principal member and 
alternate for each me mber to whic h it is entitled. 
The ALS C 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 NGRC from among its 
members.  
 11.5 Transaction of business— A majority 
of members rep resenting rules -writing a gencies 
and a m ajority of the other members shall const i-
tute a quorum to co nduct business. Each member 
shall have one vote. The majority vote of those present and votin g at a meeting shall prevail.  
 
12.  REFERENCES   30  
 
12.1 ASTM Standards9 
 
D9-12 Standard Termin ology Relating  to Wood  
and Wood Based Products  
 D1165- 18 Standard Nomenclature of Commercial 
Hard woods and Softwoods  
 
D4444- 18 Standard Test Methods fo r Laboratory 
Stan dardization and  Calibration of Hand -
Held Moisture Meters 
 
D7438- 13 Standard Practice for  Field Calibration 
and Application of Hand -Held Moisture Me-
ters 
 SI10-16 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., Checklist of Unite d States Trees 
(Native and Naturalized) , Agriculture 
Handbook No. 541 , Forest Service, U.S. 
Department of A gricu lture, Was hington 
DC 20090- 6090, 1979.  
 
 
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.   31 APPENDIX A  COMMER CIAL NAMES OF THE PRINCIPAL SOFTWOOD SPECIES  
 
The c ommercial names listed b elow are i ntended 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 c ommercial name. For stre ss-graded 
lumber, the species to be associated with a commercial name will be d etermined in accordance wi th 
6.3.2.1. These  commercial names are to be used in grading rule descriptio ns and in specifications [see 
2.15]. The provisions  of this Standard also 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 Review.   The information contained herein is a partial list of comme rcial names of the principal 
softwo od sp ecies  and species groups. Additional species and species groups are provi ded in ASTM 
Standard D 1165 -18 and the rules  certified by the Board of Review.  
 
 Commercial  Official Common  
Species or Species Group Names10 Tree Names11 Botanical Names  
CEDAR:  
Alaska C edar Alaska -cedar  Chamaecyparis  
  nootkatensis  
Incense Cedar  incense -cedar Libocedrus decurrens  
Port Orford Cedar  Port-Orford -cedar  Chamaecyparis  
  lawsoniana  
Eastern Red  Cedar  eastern redcedar  Juniperus virginiana  
 southern redcedar  J. silicicola  
Western  Red Cedar  western redcedar  Thuja plicata  
Northern White Cedar  northern w hite-cedar  T. occidentalis  
Southern Whi te Ce dar Atlantic white -cedar  Chamaecyparis thyoides  
 
CYPRE SS12 
Baldcypress  baldcypress  Taxodium distichum  
Pond  cypress  pond cypress  T. dist ichum  var. nutans  
 DOUGLAS FIR  
Douglas Fir
13  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 common ly 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 names f or lumb er. In addition to the official common na mes for a 
species, the Han dbook 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 C ypress.  Red Cypress is frequently classified 
and sold separately from t he 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.  
  32  Commercial  Official Common  
Species or Species Group Names8 Tree Names9 Botanical N ames 
FIR (continued ) 
Fraser Fir  Fraser fir  A. fraseri  
Noble Fir  noble fir  A. 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  west ern hem lock T. heterophylla  
 
JUNIP ER: 
Western Juniper  alligator juniper  Juniperus deppeana  
 Rocky Mountain juniper  J. scopulorum  
 Utah juniper  J. osteosperma  
 western juniper  J. occidentalis  
 LARCH:  
Wester n 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 p ine P. jeffreyi  
Jack Pine jack pine  P. banksiana  
Limber  Pine limber pine  P. flexilis  
Lodgepole Pine  lodgepole pine P. contorta  
Norway Pine red pine  P. resinosa  
Pitch Pine  pitch pine  P. rigida  
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  
   
  33  Commercial  Official Common  
Species  or Species  Group Names8 Tree Names9 Botanical Names  
PINE (con tinued)  
Longleaf Pine15 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  
Sout hern 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 spruc e P. engelmannii  
Sitka Spruce  Sitka spruce  P. sitchensis  
Norway Spruce     Norway spruce   P. abies  
  YEW:  
Pacific Yew  Pacific yew  Taxus brevifolia  
 
 
 
15 The commercial requirements fo r 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 sum merwood. Longleaf Pine lumb er is sometimes designated as 
Pitch Pine in the ex port trade.  
  34  
APPENDIX B  DEF INITIONS OF TERMS U SED IN DESCRIBING  
STANDA RD GRADE S OF  LUMBER  
 
 
B1. SI 10-2016  was used as the authorit ative 
standard in developing the metric dimensions 
found in this Standard. Metric dimensions are 
calculated at 25.4 millimeters (mm) times the 
dressed dimension  in inches. The nearest mm is 
signif icant for dimensions greater than 1/8 inch,  
and the nearest 0.1 mm is signif icant for dimen-
sions equal to or less than 1/8 inch.  
 The rounding  rule for dimensions greater than 
1/8 inch: if the digit in the tenths of mm p osition 
(the digit after  the decimal  point ) is less than 5, 
drop all fractio nal mm digits; if greater than 5 or 
it is 5 followed by at least one non -zero digit, 
round one mm higher;  if 5 followed by only z e-
roes, retain the digit in the unit position (the 
digit before the decimal point) if it  is even or in-
crease it one mm if it is odd. 
 
The rounding rule for dimensions equal to or 
less than 1/8 inch: if the digit in the hundredths 
of mm position (the second digit after the deci-
mal point) is less tha n 5, drop  all digits to the 
right  of the tent hs pos ition; if greater than 5 or it 
is 5 followed by at least one non -zero digit, round 
one-tenth mm higher; if 5 followed by only zeros, 
retain the digit in the tenths position if it is even 
or increase it one- tenth mm if it is odd.  
 
CAUTION:  Use great c are wh en converting 
board feet, based on  NOMINAL cross -sectional 
dimensions, to cubic met ers of lumber, based on 
DRESSED cross -sectional dimen sions. This is 
explained on page 32 of the IEEE/ASTM SI 10 -
2002 by the followin g note: “(9) No con version is 
given  for “board foot” because “board foot” i s not 
a well- defined unit of volume. Calc ulation of the 
number of board feet in a piece of lumber is based on the nominal dimensions of the cross 
section.”  
 Unfortunately,  many old er handbooks and di c-
tionaries and so me current references still con-
tain erro neous or vague information about vo l-
ume conversions to SI metric. The amount of 
dressing can also affe ct the cross -sectional d i-
mensions. Therefore, use extra care when ma k-
ing conve rsions from NOMINAL boar d foot to 
actual c ubic meters.  
 
In case of a dispute  on size measurements, the 
conventional (inch) method of measurement 
shall take prec edence.  
 
B2. Defin itions of terms used in describ-
ing sta ndard grades of lumber:  
 
air dr ied-- seasoned by exposure to the atmo s-
phere, in the open or under cover, without 
artificial heat.  
 
all-heart -- of heartwood throughout; that is, 
free of sa pwood.  
 annual ring -- denotes the amo unt of growth for 
a tree in a single year.  
 bark pocket -- patch  of bark part ially or wholly 
enclosed  in the wood . Classified by size the 
same as pit ch pockets. 
 
bevel siding — a board that has been resawn 
diagonally to be used to clad the exterior of a 
building.  
rabbeted bevel siding —bevel siding 
with a rabbeted joint milled on the 
reverse of the thick edg e to facilit ate 
alignment of pieces.  
 
blemish -- anything marring the appearance of 
lumber.  
 
bow-- see WARP.   35  
boxed heart -- with the pith enclosed in the 
piece. 
 bright -- unstained.  
 burl -- a distortion of grain, usuall y caused by 
abnormal  growth due to injury o f the tree. 
The effect of burls is assessed i n relation to 
knots.  
 Ceiling —a piece of patterned, tongue and 
grooved lumber, used to cover the ceiling of a  
room, porch or other partially enclosed areas.  
 check -- a separation of the woo d normally oc-
curring ac ross or  through the annual rings 
and usually  as a result of seasoning.  
roller check -- a crack in the wood stru c-
ture caused by a piece of cupped lu m-
ber bein g flattened in passing b e-
tween the machine roll ers. 
surfa ce check — a separatio n that oc-
curs on a face of a p iece. 
small check -- not over 0.8 m m (1/32 
inch) wide or 102 mm (4 inch) long.  
medium check -- not over 0.8 mm (1/32 
inch) wide or 254 mm (10 inch) long . 
large check -- over 0.8 mm (1/32 inch) 
wide or longer than 254 mm (10 inch) or both.   
through check -- a separation that e x-
tends from one su rface of a piece to 
the opp osite or adjoining surface.  
 
chipped grain -- a barely perceptible irregular i-
ty in the surfac e of a piece caused when pa r-
ticles of wood are chipp ed or broken below 
the lin e of cut. It is too small  to be clas sed as 
torn grain and i s not considered unless in ex-
cess of 25  percent of the surface involved.  
 chip marks -- shallow depressions or indent a-
tions on or in the surface of dressed lumber 
caused by  shavings or chips getting e mbed-
ded in the surface during dres sing. 
very light chip mark s-- not over 0.4 
mm (1/64 inch) deep.  light chip marks — not over 0.8 mm 
(1/32 inch) deep.  
medium chip marks -- not over 1 .6 mm 
(1/16 inch) deep.  
heavy chip marks -- not o ver 3.2 mm 
(1/8 inch) deep.  
 
clear-- free or practi cally  free of all  blemishes, 
characte ristics, or defects.  
 
compression wood -- abnormal wood that forms 
on the underside of leaning and crooked c o-
niferous trees.  It is characterized, aside from 
its distingu ishing color, by being hard and 
brittle and by its relatively lifeles s appea r-
ance. Co mpres sion wood shall be limited in 
effect to other appearance or strength redu c-
ing characteri stics permitted in the grade.  
 
corner-- the intersection of two adjacent faces . 
 
crook -- see WARP.  
 
cross break -- separation of t he wood a cross the 
width. 
 
crosscu tting-- cutting with a saw across the 
width.  
 cup-- see WARP.  
 cutting -- resulting pieces after crosscutting 
and/or ri pping.  
 
decay (unsound wood) -- a disintegration of th e 
wood substance due to action of wood -
destroying f ungi, and is also known a s dote 
or rot. 
advanced decay -- an older stage of de-
cay in which disintegration is recog-nized because the wood has become punky, soft, spongy, stringy, shaky, 
pitted, or crumbly. D ecided discolora-
tion or bleaching of the r otted woo d is 
often app arent.  
heart  center decay -- a localized decay 
developing along the pith in some 
species and is detected by visual in- 36 spection. Heart center decay develops 
in the living tree and does not pr o-
gress further af ter the tree is cut.  
honeyco mb-- similar to white spe cks but 
the pocket s are larger. Where permit-
ted in the grading rules, it is so li m-
ited that it has no more effect on the 
intended use of the piece than ot her 
charac teristics permitted in th e same 
grade. Pieces containing honeycomb 
are no more subject to de cay than 
pieces wh ich do not contain it.  
incipient decay -- an early stage of decay 
in which disintegration of the wood fibers has not pr oceeded far enough to 
soften or otherwise change the har d-
ness of the wood perceptibly. It is 
usual ly acc ompanied by a sli ght di s-
color ation  or bleaching of the wood.  
peck -- channeled or pitted areas or poc k-
ets found in cedar and cypress. Wood 
tissue between pecky areas remains  
unaffected in appearance and strength. All further growth of the 
fungus caus ing pec kiness ceases afte r 
the trees are felled.  
pecky -- characterized by PECK  
pocket rot -- decay which appears in the 
form of a hole, pocket, or area of soft rot, usually sur rounde d by apparently 
sound wood.  
water soak or stain -- water -soaked ar-
ea in heartwoo d, usually interpreted 
as the incipie nt stage of certain wood 
rots. 
white specks -- small white or brown pits 
or spots in wood caused by the fungus 
Fomes pini .  It develops in the living 
tree and does not develop further in 
wood in service. Where permitted in  
grading rules, it is s o limited th at it 
has no more effect on the intended 
use of the pieces than other charac-
teristics permitted in the same grade. Pieces containing white speck are no 
more subject to decay than pieces which do not co ntain it.  
 degrades -- pieces which on reinsp ection prov e 
of lower quality than the grade in which they 
were shipped.  
 
diagonal grain -- a deviation in the slope of 
grain caused by sawing at an angle w ith the 
bark of the tree. See SLOPE OF GRAIN.  
 
dry-- lumber of less than nomina l 5-inch thic k-
ness whic h has been seasoned or dried to a 
maximum moisture content of 19 percent. 
Lumber of nominal 5- inch or greater in 
thickness (timbers) is often manufactured  
and sold without drying. W hen the max i-
mum moi sture content is specified for lu mber 
of nominal 5 -inch or greater  thickness, it 
shall be in accordance with the provisions of 
the applicable lumber grading rules cert ified 
by the Board, which for some species def ines 
dry lumber as having a maximum moisture 
content higher than 19 percent  [see 2.7].  
 
eased edge -- slightly  rounded surfacing on pie c-
es of lumber to remove sharp corners.  Note: 
Lumber nominal 4 inch or less in thickness is 
frequently shipped with eased  edges unless 
otherwise specified.  
 
edge -- either : 1) the narrow face of recta ngular -
shaped pieces, or  2) the corner of a piece at 
the intersection of two longitudinal faces, or 
3) in stress grades, that part of the wide face 
nearest the corner of the piec e. 
 edge grain (EG) [vert ical grain (VG)] [rift 
grain] -- a piece or pieces s awn at approx i-
mately right angles to the annual growth 
rings so that the rings form an angle of 45 
degrees or more with the surface of the piece.  
 
equilibrium moisture content – the moisture 
content at whic h wood neither gains nor los-
es moisture when surrou nded by air at a gi v-
en relative humid ity and temperature.  
 
Finish — a high- quality piece of lumber graded 
for appearance, often used for interior trim 
or cabinet work.   37  
firm red heart -- a stage of incipient  decay 
characterized by a reddish color in the 
heartwood  which does not render the wo od 
unfit for the majority of yard pu rposes.  
 flat grain (FG) [slash grain (SG)] -- a piece or 
pieces sawn approximately parallel to the annual growth rin gs so that all or s ome of 
the rings form an angle of less than 45 d e-
grees w ith the surface of the p iece. 
 
Flooring— a tongue and grooved piece of lum-
ber typically used as a finished floor.  
 
f.o.h.c. (free of heart centers) -- without pith 
(side cut). An oc casional piece, when  showing 
pith for not more than 1/4 the length on t he 
surface, shall be accepted.  
 free of wane-- without wane but with either 
eased or square edges. (see WANE)  
 grain -- the fibers in wood and their direction, 
size, a rrangement, appearanc e, or quality.  
 
Green— lumber of less than nominal 5 -inch 
thickness, which has  a moisture content in 
excess of 19 percent. For lumber of nominal 
5-inch or greater thickness (timbers), green 
shall be defined in accordance with the pr o-
visions of the applicab le lumber grading 
rules certified by the Board [See 2.11].  
 
gum pocke t-- an ope ning between growth ring s 
which cont ains or has contained resin, or 
bark, or both.  
 gum seam -- check or shake filled with gum.  
 
gum spot -- an accumulation of gumlike sub-
stance occu rring as a smal l patch. Often o c-
curs in conjunction with a bird -peck or other 
injury to the growing wo od. 
 gum str eak-- a well -defined accumulation of 
gum in more or less regular streak. Class i-
fied as pitch streaks.   
heart center--  the pith or center core of  the log.  
 
heart face -- face side free of sapwood.  
 
heart shake -- see SHAKE --PITH  SHAKE.  
 
heartwoo d-- the inner core of the tree trunk 
comprising the annual rings containing non-
living elements. In some species, heartwood 
has a prominent color different from sap-
wood. H eartwood and sapwood of equiv alent 
charac ter are co mpared as follows : 
with regard to str ength, heartwood  
and sapwood are equal. No requir e-
ment of heartwood is made when 
strength alone is the gover ning factor.  
with regard to durability , heartwood 
is more du rable than sapwood. When 
wood is to be exposed to d ecay-
producing co nditions without pre-
servative treatment, it is permissible 
to specify the minimum percentage of 
heartwood to be present in all pieces of lumber in a shipment.  
with regard to pres ervatives, sapwood 
takes preservative treatment more readily than hear twood.  
 hit-and- miss --a series  of skips not over 1.6 mm 
(1/16 inch) deep with surfaced areas be-tween.  
 
hit-or-miss -- lumber that is completely or partly 
surfaced or entirely rough with a max imum 
scantness of 1.6 mm (1/16 inch).  
 
holes -- openings t hat either extend pa rtially or 
wholly through a piece. An alternate desi g-
nation for holes which extend only partially 
through a piece is surface pits. Holes are 
class ified by size as follows:  
pin hole-- not over 1.6 mm (1/16 inch) in 
diameter.  
medium hole — (small hole) not ov er 6 
mm (1/4 inc h) in diameter.  
large hole -- not over 25 mm (1 inch) in 
diameter.   38 very large hole-- over 25 mm (1 inch) in 
diameter.  
 
kiln-dried — seasoned in a chamber by means 
of artificial heat.  
 
knife marks -- the imprints or marking s of the 
machine knives  on the sur face of dress ed 
lumber.  
very slight knife marks -- marks that 
are visible only from a favorable angle and are perfectly smooth to the touch.  
slight knife marks -- marks th at are 
readily visible but evidence no un e-
venness to the touch.  
 
knot -- a porti on of a bra nch or limb t hat has be-
come incorporated in a piece of lumber. In 
lumber, knots are classified as to form, size, 
quality, and occurrence.  
 
 knot form--  
oval knot -- produce d when the limb is 
cut at slightly more than a r ight angle 
to the long axis . 
round  knot-- produced w hen the limb  is 
cut at approximately right angles to its long axis.  
spike knot -- produced when the limb is 
cut either lengthwise or diagonally.  
 
 knot si ze-- 
pin knot -- not over 13 mm (1/2 inch) in 
diamet er. 
small knot -- not over 19 mm  (3/4 inch) 
in diameter.  
medium knot -- not over 38 mm (1- 1/2 
inch) in d iameter.  
large knot -- over 38 mm (1- 1/2 inch) in 
diameter.  
 
 knot quality -- 
black knot -- results from a  dead b ranch 
which the wood growth of the tree has 
surrounded.  
decayed knot -- softer than the sur-
round ing wood , and contai ning ad-
vanced decay.  encased knot -- not intergrown with the 
annual rings of the surrounding wood.  
firm knot —  solid across its face bu t con-
tains incipient decay.  
fixed knot -- retains it s place in dry lu m-
ber under ordina ry conditions but is 
movable under pressu re though not 
easily pushed out.  
hollow knot -- a sound knot containing a 
hole greater than 6 mm (1/4 inch) in diameter. The throug h opening of a 
hollow knot is limited to the size of 
other holes permitted.  
intergrow n knot— a knot whose annual 
rings are parti ally or completely in-
tergrown on one or more faces with the annual rings of the surrounding wood.  
loose knot -- not firmly fixed;  a knot not 
held tightly in place by growth, shape,  
or position.  
pith knot -- sound in all respects except it 
contains a pith hole not over 6 mm 
(1/4 inch) in diameter.  
red knot -- knot that results from a live 
branch grown in the tree and is inte r-
grown with  the su rrounding wood.  
sound knot — contains no decay.  
star-checked knot -- has radial  checks. 
tight knot -- so fixed by gr owth, shape,  or 
position that it retains its place in the piece.  
unsound knot — contains decay.  
water -tight knot -- has annual rings 
completely intergrown with those of 
the surrounding woo d on one surface 
of the piece, and  it is sound o n that 
surface.  
  knot occurrence -- 
branch knots -- two or more divergent 
knots sawed lengthwise and tapering 
toward the pith at a common point.  
corner knot -- located at the inters ection 
of adjacent faces.  
knot cluster — two or more knots 
group ed together as a  unit with the  39 fibers of the wood d eflected around 
the entire unit. A group of single 
knots is not a knot cluster.  
single knot -- occurs by itself. The fibers 
of the wood being deflected around it.  
 
loosened  grain -- a grain separation or loo sen-
ing between sp ringwood and summerwood 
without di splacement.  
very light loosened grain -- not over 0.4 
mm (1/64 inch) separation.  
light loosened grain -- not over 0.8 mm 
(1/32 inch) separation.  
medium loosened grain -- not over 1.6 
mm (1/16 inch) separation.  
heavy loosened gra in-- not over 3.2 mm 
(1/8 inch) separ ation.  
very heavy loosened grain -- over 3.2 
mm (1/8 inch) separation.  
 
lumber -- Lumber is defined as a manufacture d 
product derived from a log  through sawing or 
planing .   
 
machine bite -- a depressed cut of the machine 
knives at the end of a piece.  
very light  machine bite -- not over 0.4 
mm (1/64 inch) deep.  
light machine bite -- not over 0.8 mm 
(1/32 inch) deep.  
medium machine bite -- not over 1.6 
mm (1 /16 inch) deep.  
heavy machine bite -- not over 3.2 m m 
(1/8 inch) deep.  
very heav y machine bite — over 3.2  mm 
(1/8 inc h) deep.  
 
machine burn-- a darkening of the wood due to 
overheating by machine knives or rolls when 
pieces are stopped in the machine.  
 
machine  gouge-- a groo ve cut by the machine 
below the de sired line. 
very light machine  gouge -- not over 0.4 
mm (1/64 inch) deep.  
light machine gouge -- not over 0.8 mm 
(1/32 inch) deep.  medium machine gouge -- not over 1.6 
mm (1/ 16 inch) deep.  
heavy machine gouge -- not over 3.2 
mm (1/8 inch) deep.  
very heavy mach ine gouge -- over 3.2 
mm (1/8 inch) d eep. 
 
machine offset -- an abrupt dre ssing variation 
in the edge surface which usually occurs near 
the end of the piece without reducing  the 
width or without changing the plane of  the 
wide surface.  
very light machine offs et-- a variation 
not over 0.4 mm (1/64  inch).  
light machine offset -- a var iation not 
over 0.8 mm (1/32 inch).  
medium machine offset -- a variation 
not over 1.6 mm (1/16 inc h). 
heavy machine offset -- a variation not 
over 3.2 mm (1/8 inch).  
very heavy machine offset-- a variation 
over 3.2 mm (1/8 inc h). 
 
metric units — See B 1. 
 
mismanufacture -- includes all defects or blem-
ishes, produced in manufacturing.  See CHIPPED GRAIN, HI T-AND -MISS, HIT -
OR-MISS, LOOSENED GRAIN, MACHINE 
BURN, MACHINE GOUGE, MISMATCHED 
LUMB ER, RAISED GRAIN, SKIP, TORN 
GRAIN, and VARI ATION IN SAWING.  
 misma tch-- an unev en fit in worked lumber 
when ad joining pieces do not meet tightly at 
all points of contact or when the surfaces of adjoining pieces are not in  the same plane.  
slight mismatch -- a barely evident trace 
of mis match.  
very lig ht mismatch -- not over 0. 4 mm 
(1/64 i nch).  
light mismatch -- not over 0.8 mm (1/32 
inch).  
medium mismatch — not over 1.6 mm 
(1/16 inch).  
heavy mismatch -- not over 3.2 mm (1/8 
inch).  
  40 mixed grain (MG )— either verti cal or flat 
grained pieces or both.  
 
moisture con tent-- the weight of the water in a 
piece of lumber expressed in a percentage of 
the weight of the piece after being over dried.  
 
occasional pieces -- not more than 10% of t he 
pieces  in a parcel or shipment.  
 
partition — a tongue and grooved piece of lu m-
ber w ith the same pattern run  on both sid es. 
For use where both sides may be exposed.  
 pitch -- an accumulation of resinous material.  
light pitch -- the light but evident pre s-
ence of pitc h. 
medium pitch -- a somew hat more ev i-
dent presence of pitch than in the light p itch. 
heavy pitch — a ver y evident ac cumul a-
tion of pitch showing by its color and 
consi stency.  
massed pitch -- a clearl y defined accu-
mulation of solid pitch in a body by i t-
self. 
 
pitch seam -- a shake or c heck which contains 
pitch.  
 pitch streak -- a well- defined  accumulation of 
pitch i n the wood c ells in a streak.  Pitch 
streaks, with equivalent areas being permi s-
sible, are described as follows:  
very small pitch streak — 10mm (3/8 
inch) i n width and 381 mm ( 15 inch) 
in length.  
small pitch streak -- 1/12 the width and  
1/6 the length of the p iece. 
medium pitch streak -- 1/6 the width 
and 1/3 the length of the piece.  
large pitch s treak -- not over 1/4 the 
width by 1/2 the length of  the sur face. 
very large pitch str eak-- over 1/4 the 
width by 1/2 the length of the sur face. 
 pith-- the small soft core in the struc tural center 
of a log.  very small pith -- not over 3.2 mm (1/8 
inch) wide  and occupies on the face 
surface not over 161 square mm (1/4 
square inch)  [3.2 mm by  51 mm (1/8 
inch wide by 2 inch long), or 1.6 mm 
by 102 mm (1/16 inch by 4 inch)]  
small pith-- not ov er 484 square mm 
(3/4 square inch) on the face surface [6 mm by 76 mm (1/4 inch by 3 inch), 
5 mm by 102 mm (3/16 inch by 4 inch), 3.2 mm by 152 m m (1/8 inc h by 
6 inch), or 1.6 mm by 305 mm (1/16 
inch by 12 inch)]  
free of  pith-- the prohibition of pith on or  
within the body of the piece.  
boxed pith -- pith that is within the f our 
faces of an end of a piece.  
 
pocket -- a well -defined opening, between t he 
rings o f annual growth, which develops du r-
ing the growth of the tree. It us ually contains 
pitch or bark. Pocket s are described as fol-
lows with equivalent areas being permiss i-
ble: 
very small pocket — 1.6 mm (1/16 inch) 
in width and  76 mm (3 inch) in 
length , or 3.2 mm (1/8 inch) in width 
and 51 mm (2 inch) in length.  
small pocket — 1.6 mm (1/16 inch) in 
width  and 152 mm (6 inch) in length, 
or 3.2 mm (1/8 inch) in width and 102 mm (4 i nch) in length, or 6 mm (1/4 
inch) in width and 51 mm (2 inch) in length.  
medium pock et— 1.6 mm (1/16 inch) in 
width and 305 mm (12 inch) in 
length, or 3.2 m m (1/8 inch) in width 
and 203 mm (8  inch) in length, or 10 
mm (3/8 inch) in width and 102 mm 
(4 inc h) in length.  
large pocket — not over 2581 square 
mm (4 square inches) in area.  
very large pocket -- over 2581 square 
mm (4 square inches) in area.  
closed pock et-- an opening on one su r-
face only.  
open (through) pocket -- an opening on 
opposite surfaces. A thr ough opening  41 is considered the same as a through 
hole of equal size.  
 
raised grai n— a roughened condition of the 
surface of dressed lumber in which the hard 
summerwood is raised above the softer 
springwood, but not torn loose from it.  
very light raised gra in-- not over 0.4 
mm (1/64 inch).  
light raised gra in-- not over 0.8 mm 
(1/32 inch).  
medium raised grain -- not over 1.6 mm 
(1/16 inch).  
heavy raised grain -- not over  3.2 mm 
(1/8 inch).  
 resawn lumber -- the product of sawing any 
thickness of lumber to develop thinner lu m-
ber. 
 
ripped lumber -- the product of sawing any 
width of lumber to deve lop narrower lumber.  
 sapwood -- the outer layers of growth between 
the bark and he artwood that contain the  sap. 
bright  sapwood — sapwood that shows 
no stain and is not limi ted in any 
grade unless specifically stated in the grade description.  
sapwood restric tions waived-- a lifting 
of any restrictions in a rule on the 
amount of sapwood per mitted in piec-
es graded under that r ule. 
bright sapwood no defect (BSND) -- an 
indication  that bright sapwood is 
permitted in each piece in any 
amount.  
 
seasoning -- evaporati on or extraction of mois-
ture from green or partially dried wood.  
 
shake -- a lengthwise  separation of the wood 
which occurs  between or through the rings of 
annual growth.  
fine shake -- a barely perceptible open-
ing. 
light sha ke-- not over 0.8 mm (1/32 inch) 
wide. mediu m shake -- not over 3.2 mm (1/8 
inch) wide.  
open shake -- over 3.2 mm (1/8 inch) 
wide. 
ring shake -- occurs between the annual 
rings to partially or wholly encircle 
the pith.  
surface shake -- occurs on only one su r-
face of a piece.  
through shake -- extends from one s ur-
face of a piece to the opposite or to an 
adjoining surface.  
pith shake (hear t check or heart 
shake) -- extends through the annual 
rings from or through the  pith to-
wards the surface of a piece, and is 
distin guished from a seasoning check 
by the fact that it s greatest width is 
nearest the pith, whereas the greatest 
width of a season c heck in a pith -
centered piece is far thest from the 
pith.  
 side cut -- pith is not enclosed within the four 
sides of the piece.  
 
skip-- area on a piece that failed to surface 
clean. Skips are described as follows:  
very light skip --not over 0.4 mm (1/64 
inch) d eep. 
light skip --not over 0.8 mm (1/ 32 inch) 
deep.  
medium skip --not over 1. 6 mm (1/16 
inch) deep.  
heavy skip -- not over 3.2 mm  (1/8 inch) 
deep.  
 slope of grain -- the deviation of t he line of fi-
bers from a straight line parallel to the sides of the piece.  
 
Softwood — one of the group  of trees wh ich have 
needle- like or scale- like leaves. The term has 
no specific reference to the sof tness of the 
wood.  
 
sound -- free of d ecay. 
  42 spiral grai n-- a deviation in the slope of grain 
caused when the fibers in a tree take a s piral 
course around the trunk of the  tree instead of 
the normal vertica l course.  
 
split -- a separation of the wood through  the 
piece to the opposite surface  or to an adjoin-
ing su rface due to the tearing apart of the 
wood cells.  
very short split -- equal in le ngth to 1/2 
the width of  the piece.  
short split --equal in length to t he width 
of the piece and in no case exceeds 1/6 the length.  
medium split -- equal in len gth to twice 
the width  of the piece and in no case 
exceeds 1/6 the length.  
long split -- longer than a medium split.  
 springwo od-- the portion of the annual ring 
formed during the early part of the yearly 
growth period. It is lighter in color, less dense , and not as strong mechani cally as 
summe rwood.  
 
square corners -- without eased edges but has 
an allo wance for wane in certain grades.  
 
square  edged -- free from wane and w ithout 
eased edges.  
 
stained wood -- a discoloration  in wood.  
stained heartwood or fir m red heart --
heartwood that sh ows a marked var i-
ation from the natural color. In 
grades where it is permitted,  stained 
heartwood has no more effect on the 
intended use of a  piece than other 
characteristics permitted in the 
grade.  Note: Stained heartwood ran g-
es from pink to brown, and is  not to be 
confused with natural red heart. Nat-
ural color is usually uniformly  dis-
tributed through cer tain annual rings, 
whereas stains are u sually in irreg u-
lar patches.  
stained sapwood—  sapwo od with dis-
coloration. In grades w hen it is per-mitted, stained s apwood has no more 
effect on the intended use of a piece 
than other characteri stics permitted 
in the g rade but it does affect appea r-
ance in v arying d egrees:  
light stained sapwood —  a dis-
coloration so slight that it does 
not af fect natural fi nishes.  
medium s tained sapwood a 
pronounced difference in color-
ing. Note: Sometimes the use-
fulness for natural finish es but 
not for paint finishes is affect-
ed. 
heavy stained sapwood—  a so 
pronounced di fferen ce in color 
that the grain of the wood is 
obscured, but lumber c ontain-
ing it is acceptable for paint finishes.  
stained wood resulting from exp osure 
to the elements -- discolored wood 
that is permitted in al l grades of 
framing and sheathing lumber.  
 Stepping — lumber designed to be used for s tair 
treads. Customarily surface d three sides and 
bull-nosed on one edge.  
 stress grades -- lumber having assigne d work-
ing stresses and modulus of elasticity values 
in acco rdance with accepted basic principles 
of strength g rading, and the provisions of 
6.3.2.1 and 6.3.2.2 of this Standard.  
 summerwood -- the portion of the annual ring 
formed during the latter part of t he yearly 
growth. It is  darker in c olor, more dense, and 
stronger mechanically than spring wood.  
 torn grain -- an irregularity in the surface of  a 
piece where wood has been torn or b roken 
out by surfacing.  
very light torn grain -- not over 0.4 mm 
(1/64 inch) d eep. 
light torn grain -- not over 0.8 mm (1/32 
inch) deep .  43 medium torn grain -- not over 1.6 mm 
(1/16 inch) d eep. 
heavy torn grain -- not over 3 .2 mm (1/8 
inch) deep.  
very heavy torn gra in-- over 3.2 mm 
(1/8 inch) deep.  
 
trim -- to cross -cut a piece to a given len gth. 
double -end trimmed (DET) -- lumbe r 
trimmed square on both ends. Toler-
ances are found in certified g rading 
rules.  
precision -end trimmed (PET)-- lumber 
trimmed square on both en ds to un i-
form lengths with a manufacturing tolerance of 1.6 mm (1/16 inch) ove r 
or under in length in 20% of the p iec-
es. 
square -end trimmed -- lumber trimmed 
square and having a manufacturing 
tolerance of 0.4 mm (1 /64 inch) for 
each nominal 2 inch of thickne ss or 
width.  
 
Unsound — see DECAY.  
 
variation in sawing -- a deviation from the l ine 
of cut.  
slight var iation --not over 1.6 mm ( 1/16 
inch) scant in nominal 1- inch lumber, 
3.2 mm ( 1/8 inch) in nominal 2- inch, 5 
mm (3/16 inch) in nominal 3- inch to 7-
inch, and  6 mm (1/4 inch) in nominal 
8-inch and greater thickness or width.  
 wane -- bark  or lack of wood from an y cause, e x-
cept eased ed ges, on the edge or corner of a 
piece of lumber.  
 
warp-- any deviation from a true or  plane su r-
face, i ncluding bow, crook, cup, twi st, or any 
combination thereof. Warp restrictions are 
based on the average for m of warp as it oc-
curs n ormally, and  any variat ion from this 
average form, such as short kinks, sh all be 
appraised according to its equiv alent effect. 
Pieces containing two or more forms of warp 
shall be ap praised according to the combined effect in determ ining the amount permiss i-
ble. In grading rules,  warp is classified as 
very light, light, medium, a nd heavy, and 
applied to each widt h and  length as set forth 
in the various grade s in accordance with the 
following prov isions:  
bow-- a deviation flatwise from a  straight 
line drawn fr om end to en d of a pie ce. 
It is measured at the point of greatest 
distance from the straight line.  
crook -- a deviation edgewise from a 
straight line drawn  from end to end of 
a piece. It is measured at the point of greatest distance f rom the straight 
line. 
cup-- a devia tion in the face of a piece 
from a straight line drawn from  edge 
to edge of a piece. It is measure d at 
the point of greatest distance from the  
straight line.  
twist -- a deviation flatwise, or a combi-
nation of flatwise and e dgewise, in 
the form of  a curl or s piral, and the 
amount is the distance an edge of a 
piece a t one end is raised above a flat 
surface against which both edges at 
the opposite en d are res ting snugly.  
 wavy dressing -- an involvement of more une-
ven dressing t han knife marks.  
very li ght wavy dre ssing -- not over 0.4 
mm (1/64 inch) deep.  
light wavy dres sing-- not over 0.8 mm 
(1/32 inch)  deep. 
medium wavy dressing -- not over 1.6 
mm (1/16 inch)  deep.  
heavy wavy dressing -- not over 3.2 mm 
(1/8 inch) deep.  
very heavy wav y dressing -- over 3.2 
mm (1/8 inch) d eep.    44 APPENDIX C  LUMBER INDUSTRY ABBREVIATIONS  
 
 These abbreviations are commonly use d for softwood lumber, although all of them are not 
necessarily applicable to all species. Additional abbreviations which are applic able to a particular re gion 
or spec ies shall not be used unless included in certified g rading 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 n ot required.  
  AD Air-dried  
 ADF  After deducting f reight sides  
 ALS American Softwoo d 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   45  E&CB2S  Edge and center bead two sides  
 E&CV1S  Edge and c enter Vee one side  
 E&CV2S  Edge and  center Vee two sides  
 EE Eased edges  
 EG Edge (vert ical) 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 boa rd (named point)  
 FOHC  Free of heart center or cent ers 
 FOK  Free of knots  
 Frt Freigh t 
 Ft Foot or feet  
 GM Grade marked  
 G/R or G/Rfg  Grooved 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 measur e 
 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   46  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 len gths 
 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 s iding  
 SE & S  Square ed ge and sound  
 S/L or S/LAP Shiplap  
 SL&C  Shipper's load and coun t 
 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  Surfac ed 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 Weig ht  47 APPENDIX D  IMPLEMENTATION  AND MAINTENANCE OF STANDA RD 
 
D1. STANDING COMMITTEE  
 
The American Lumber Standard Committee (ALSC) ac ts as the Standing Commi ttee for this  
Standard for the purpose of its interpretation 
and for considering future proposals for  
amendments and revisions. Members of the 
ALSC and th eir alternates are appointed by the 
Secretary of Commerce in accordance with 
Section 9 of this Standar d. The names  of the 
members are available from the Committee's 
secretariat: Standards Services  Division , 
National Institute of Standards and Technology, 
Gaithersburg, Maryland 20899- 2100. Comments 
regarding the Standard and suggesti ons for its 
amendment or revision ma y also be sent to this 
address. No product shall be advertised or 
represented in any m anner  that would imply 
approval or endorsement of that prod uct by the 
National Institute of Standards and Technology 
and/or the Departm ent of Commerce.  
 
D2. EFFECTIVE DAT E 
 Voluntary Product Standard PS 20 -20 Revision 
1, American Sof twood Lumber Standard , a 
voluntary standard developed under the 
Department of Commerce proced ures, shall be 
effective October 2021 for products produced 
thereunder o n and after that date. The S tandard 
being superseded, American Softwood Lumber 
Standard PS 20- 20, is effective for  products 
produced thereunder through  October , 2021.  
 D3. HIST ORY OF THE STANDARD  
 
Early in 1922 Secretary of Commerce Herbert 
Hoover, respon ding to a request from the lumb er 
industry,  offered the cooperation of the 
Department in ac tivities directed towar d 
simplification, standardization, and development 
of adequate quality guarantees for the lumber -
consuming public. This cooperation led to th e 
development and publication in  1924 of 
Simplified Practice Recommendation R 16 under 
the g uidance of the Departme nt's Division of 
Simplified Practices, which was to become a pa rt 
of the National Bureau of Standards (now the National Institute of Standard s and 
Technology). The history of R 16's dev elopment 
and its subsequent revisions is summari zed in 
editions issued,  respectively, in 1924, 1925, 
1926, 1929, 1939, and 1953.  
 
R 16-53 was rev ised in 1969 and superseded by 
Voluntary Product Standard PS 20 -70 American 
Softwood Lumber Standar d. The signi ficant 
provisions added to PS 20 -70 were: 1) sep arate 
size standards fo r dry and green lumber, under 
nominal 5- inch thickness, were es tablished i n 
order to achieve greater uniformity in the 
dimensions of seasoned  and unseasoned lumber 
at the po int of use; 2 ) an independent National 
Grading Rule Committe e was created to 
establ ish and maintain a national grading rule 
for dimension lumber c onforming t o PS 20; 3) an 
independent Board of Review was formed to 
assure uni form approval of grading rules a nd of 
agenci es to grade under these rules, and to 
enhance enforcement of the accredita tion 
program ; 4) the composition of the American Lumber Sta ndard Commi ttee was expanded to 
reflect a broader representation of interests;  and 
5) uniform methods for assi gnment of de sign 
values were accepted. Non -substantive chang es 
were made to the Sta ndard in 1985, 1991, 1992,  
1999, 2005, 2010, and 2015.  The  Standard was 
reviewed  in 2019 to assure it reflected the needs 
of manufactur ers, distributors and consumers.  
 
D4. CURREN T EDI TION  
 
The current edition, PS 20 -20, has the sam e 
technical requirement s and administrative 
structure for implementing and enfo rcing the 
Standard as its  previous edition. This new 
edition was based on the r ecommendations 
resulting from an extensive technic al and 
editorial review of PS 20 -15 conducted by  the 
Standing Committee  with the assistance from 
the National Institute of St andards and 
Technology in 2 019.