Voluntary Product Standard

PS 20-10

American

Softwood

Lumber

Standard

American

Softwood

Lumber

Standard

National Institute of Standards and Technology

U.S. Department of Commerce
Voluntary Product Standard PS 20-10

American Softwood Lumber Standard

Supersedes Voluntary Product Standard PS 20-05

June 2010

U.S. Department of Commerce

Gary Locke, Secretary

National Institute of Standards and Technology

Patrick D. Gallagher, Director
National Institute of Standards & Technology Voluntary Product Standard PS 20-10

Natl. Inst. Stand. Technol. Prod. Stand. PS 20-10, 50 pages (June 2010)

CODEN: NSPUE2

U.S. Government Printing Office

Washington: 2010

For sale by Superintendent of Documents, U.S. Government Printing Office

Internet: bookstore.gpo.gov – Phone: (202) 512-1800; Fax: (202) 512-2250

Mail: Stop SSOP, Washington, DC 20402-0001
iii

VOLUNTARY PRODUCT STANDARDS

Development of Voluntary Product 

Standards

Voluntary Product Standards are developed 

under procedures published by the Department 

of Commerce in Title 15 Code of Federal 

Regulations Part 10, Procedures for the 

Development of Voluntary Product Standards. 

The purpose of these standards is to establish 

nationally recognized requirements for products 

and provide all concerned interests with a basis 

for common understanding of the 

characteristics of the products. The National 

Institute of Standards and Technology (NIST) 

administers the Voluntary Product Standards 

Program on a reimbursable basis.

Role of NIST

The role of NIST in the establishment of 

Voluntary Product Standards is to act as an 

unbiased coordinator in their development, 

provide editorial assistance in their 

preparation, supply such assistance and review 

as is required to assure their technical 

soundness, and to seek satisfactory adjustment 

of valid points of disagreement. NIST also 

determines compliance with the criteria of the 

Department’s procedures, provides secretarial 

functions for each committee appointed under 

the procedures, and publishes the standards as 

public documents.

Producers, distributors, users, consumers, and 

other interested groups contribute to the 

establishment of Voluntary Product Standards 

by initiating and participating in their 

development, providing technical or other 

counsel as appropriate, promoting the use of 

and support for the standards, and assisting in 

keeping the standards current with respect to 

advancing technology and marketing practices.

Use of Voluntary Product Standards

The use of Voluntary Product Standards is 

voluntary. NIST has no regulatory power in the 

enforcement of their provisions; however, since 

the standards represent a consensus of all 

interested groups, their provisions are likely to 

become established as trade customs. In 

addition, when a Voluntary Product Standard 

is made a part of a legal document, such as a 

sales contract or code, compliance with the 

standard is enforceable.

The benefits derived from Voluntary Product 

Standards are in direct proportion to their 

general recognition and actual use. Producers 

and distributors whose products meet the 

requirements of a Voluntary Product Standard 

may refer to the standard in advertising and on 

labels to promote greater public understanding 

for confidence in their products. At times, 

purchasers may order products conforming to 

the requirements of a Voluntary Product 

Standard.

For copies of the Voluntary Product Standards 

procedures or for more information concerning 

the development and use of these standards, 

contact the Standards Services Division, 

National Institute of Standards and 

Technology, Gaithersburg, MD 20899-2150.
iv

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v

Voluntary Product Standard

PS 20-10

(Supersedes Product Standard PS 20-05)

AMERICAN SOFTWOOD LUMBER STANDARD

PREFACE

The American Softwood Lumber Standard was developed by the American Lumber 

Standard Committee (ALSC) in accordance with the Procedures for the Development of Voluntary 

Product Standards of the U.S. Department of Commerce. The ALSC membership is appointed by 

the Secretary of Commerce to constitute a proper balance among producers, distributors, and 

consumers of softwood lumber. Pursuant to a U.S. District Court order, the ALSC and its Board 

of Review (Board) operate as independent bodies with defined functions with regard to 

establishing, maintaining, implementing and enforcing this Standard. Through a consensus 

process, the ALSC maintains the Standard and establishes policies and adopts other standards 

by which the Board certifies grading rules, approves design values, accredits agencies to grade 

and inspect under those rules and monitors the agencies' performance. The purpose of this 

standardization program for manufacturers, distributors, users and consumers is to provide for 

the correct grade mark labeling of lumber by mills using the service of an accredited agency. This 

Standard provides for the grading of structural lumber by both visual and mechanical means. 

Any design values assigned to lumber are required to be in accordance with the criteria 

determined appropriate by the National Institute of Standards and Technology. A separate 

consensus body, the National Grading Rule Committee (NGRC) is established to develop and 

maintain nomenclature and descriptions of grades for dimension lumber that conform to this 

Standard.

This Standard is used for domestic production consumed in and exported from the United States, 

and for lumber imported into the United States. 
vi

ABSTRACT

This Standard pertains to softwood lumber. It 

establishes standard sizes and requirements for 

development and coordination of the lumber 

grades of the various species, the assignment of 

design values when called for, and the 

preparation of grading rules applicable to each 

species. It provides for implementation of the 

Standard through an accreditation and 

certification program to assure uniform 

industry-wide marking and inspection.

It establishes principal trade classifications and 

lumber sizes for yard, structural, factory and 

shop use and provides for the classification, 

measurement, grade marking of rough and 

dressed sizes of lumber items. Terms and 

procedures are defined to provide a basis for the 

use of uniform methods in the grading, 

inspection, measurement and description of 

softwood lumber. It includes the organization 

and functions of the American Lumber 

Standard Committee, the Board of Review, and 

the National Grading Rule Committee. 

Commercial names of the principal softwood 

species, definitions of terms used in describing 

standard grades of lumber and commonly used 

industry abbreviations are also provided.

The Standard was developed by the American 

Lumber Standard Committee in accordance 

with procedures of the U. S. Department of 

Commerce.

KEY WORDS

Accreditation; ALSC Board of Review; 

certification of grading rule; DOC PS 20-10; 

lumber inspection; lumber sizes; moisture 

content of lumber; National Grading Rule; 

softwood lumber standard.
vii

TABLE OF CONTENTS

PREFACE............................................................................................................................. v

1. SCOPE............................................................................................................................. 1

2. TERMINOLOGY.............................................................................................................. 2

3. CLASSIFICATION .......................................................................................................... 3

4. MEASUREMENT AND TALLY....................................................................................... 4

5. LUMBER SIZES.............................................................................................................. 5

6. GRADING RULE REQUIREMENTS ............................................................................ 10

7. GRADE MARKING (GRADE STAMPING).................................................................... 13

8. INSPECTION AND REINSPECTION........................................................................... 14

9. AMERICAN LUMBER STANDARD COMMITTEE ...................................................... 16

10. BOARD OF REVIEW................................................................................................... 18

11. NATIONAL GRADING RULE COMMITTEE.............................................................. 21

12. REFERENCES ............................................................................................................ 21

APPENDIX A COMMERCIAL NAMES OF THE PRINCIPAL SOFTWOOD SPECIES.... 23

APPENDIX B DEFINITIONS OF TERMS USED IN DESCRIBING

STANDARD GRADES OF LUMBER............................................................. 26

APPENDIX C LUMBER INDUSTRY ABBREVIATIONS ................................................ 37

APPENDIX D IMPLEMENTATION AND MAINTENANCE OF STANDARD.................. 40
viii

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1

AMERICAN SOFTWOOD LUMBER STANDARD

Effective June 1, 2010

[This Standard which was initiated by the American Lumber Standard Committee has been developed 

under the Procedures for the Development of Voluntary Product Standards of the U.S. Department of

Commerce to supersede PS 20-05 “American Softwood Lumber Standard.”]

1. SCOPE

1.1 General

1.1.1 This Voluntary Product Standard 

establishes and maintains, through a consensus 

process and in the public interest, standard sizes 

(both in metric1 and conventional units) and 

general requirements for developing grades of 

softwood lumber. It is implemented through an 

internationally recognized consensus 

accreditation and certification program, the 

purpose of which is to provide for uniform, 

industry-wide grade marking and inspection of 

softwood lumber.

1.1.2 This Standard also provides a basis for 

the coordination of the grades of the various 

species of softwood lumber, the assignment of 

design values to lumber when called for, and the 

preparation of grading rules applicable to each 

species. The provisions of this Standard apply to 

structural lumber manufactured from hardwood 

species or lumber manufactured from foreign 

species when the species is included in rules 

certified by the Board of Review. It is not

intended to be used either as grading rules or as 

purchase specifications. Italicized notes in this 

Standard are nonmandatory.

 1 Metric units are provided initially followed by 

conventional units.

1.1.3 It establishes the principal trade 

classifications and sizes of softwood lumber for 

yard, structural, factory and shop use. It 

provides for the classification, measurement, 

grading and grade marking of rough and dressed 

sizes of various items of lumber including finish, 

boards, dimension and timbers. Terms and 

procedures are defined and discussed to provide 

a basis for the use of uniform methods in the 

grading, inspection, measurement and 

description of softwood lumber.

Note: The provisions of this Standard do not 

apply to the myriad of products of remanufacture 

(for example: turned balusters, peeler cores, etc.) 

or manufactured components (for example: 

trusses, 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 identified as a manufactured product from 

a softwood log in a sawmill, or in a sawmill and 

planing mill. Such lumber, when rough, shall 

show saw or other primary manufacturing marks 

in the wood on the four longitudinal surfaces of 

each piece for its over-all length and shall not 

have been further manufactured other than by 

crosscutting, ripping, resawing, joining by 

fingerjointing, face-gluing and/or edge-gluing, 
2

surfacing with or without end matching, and 

working.

1.1.5 In this Standard, lumber conforming to 

the basic minimum size and grade provisions 

herein is designated “American Lumber 

Standard” (ALS) program lumber only when 

graded under rules certified by the Board of 

Review (Board).

1.2 This Standard also includes the 

following:

(a) Organization and functions of the 

American Lumber Standard Committee 

(ALSC), the Board, and the National 

Grading Rule Committee (NGRC) 2

(b) Commercial names of the principal 

softwood species (Appendix A);

;

(c) Definitions of terms used in describing 

standard grades of lumber (Appendix B);

(d) Commonly used lumber industry 

abbreviations (Appendix C); and

(e) Information on implementation, and 

history of the Standard (Appendix D).

2. TERMINOLOGY

2.1 Accreditation-Procedure by which an 

authoritative body gives formal recognition that a 

body or person is competent to carry out specific 

tasks.

2.2 Board measure-The term used to 

indicate that a board foot is the unit of 

measurement of lumber. The number of board feet 

in a piece of lumber is obtained by multiplying the 

nominal thickness in inches or fraction of an inch 

by the nominal width in feet by the length in feet. 

For metric measurement, [see 2.5]

 2 The American Lumber Standard Committee, Inc., its 

Board of Review, and its National Grading Rule 

Committee disclaim any liability for damages, including 

consequential damages, in connection with the use or 

performance in use of products produced.

2.3 Certification-Procedure by which a 

third party gives written assurance that a 

product, process or service conforms to specified 

requirements.

2.4 Characteristics-Distinguishing 

features which by their extent, location, and 

number determine the quality of a piece of 

lumber. The limiting characteristics of any grade 

of lumber described in certified grading rules shall 

be expressed within the terms of the definitions in 

Appendix B.

2.5 Cubic measurement-The term used to 

indicate that a cubic meter is the metric unit of 

measurement of lumber. The number of cubic 

meters in a piece of lumber is obtained by 

multiplying the dressed thickness in millimeters 

by the dressed width in millimeters by the length 

in meters, and dividing the product by 1,000,000. 

[see Appendix B1]

2.6 Design values-Mechanical properties of 

wood as prepared for design use. Allowable 

properties of wood are identified with stress-grade 

descriptions and reflect the orthotropic structure 

of wood.

2.7 Dry lumber-Lumber of less than 

nominal 5-inch thickness which has been 

seasoned or dried to a maximum moisture content 

of 19 percent.

Note: Lumber of nominal 5-inch or greater 

thickness (timbers) is often manufactured and sold 

without drying.

When the maximum moisture content is specified 

for lumber of nominal 5-inch or greater 

thickness, it shall be in accordance with the 

provisions of the applicable lumber grading rules 

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] 
3

2.8 Grade marked (grade stamped)-

Lumber that displays the official grading mark of 

an agency that is made by rubber stamps, ink jet 

sprayers, tags and/or other methods when found 

acceptable by that agency. A grade mark is owned 

by the grading agency and is applied to lumber 

that conforms to the requirements of a designated 

grading rule. Except for marks used in connection 

with Certificates of Inspection or Reinspection, all 

grade marks shall indicate the following: 1) the 

mill number, name, or abbreviation; 2) the agency 

symbol; 3) the species or combination of species of 

the lumber; 4) for lumber of less than nominal 5-

inch thickness, whether the lumber was dry or 

green when dressed; and 5) the appropriate grade. 

Where required by the grading rules, grade marks 

shall also denote rule paragraphs under which the 

lumber was graded or other similar information.

2.9 Grading agency-An organization 

accredited by the Board that engages in the 

grading of lumber or that licenses and supervises 

facilities that employ graders to grade and/or to 

place grade marks upon lumber products.

2.10 Grading rules-Requirements and 

specifications for the manufacture, inspection and 

grading of designated species of lumber. Lumber 

manufactured and graded according to the 

provisions of this Standard and the grading rules 

for the species in question shall be regarded as 

ALS program lumber.

2.11 Green lumber-Lumber of less than 

nominal 5-inch thickness which has a moisture 

content in excess of 19 percent. For lumber of 

nominal 5-inch or greater thickness (timbers), 

green shall be defined in accordance with the 

provisions of the applicable lumber grading rules 

certified by the Board.

2.12 Heat treated (HT)-lumber or other 

wood products that have been heated in a closed 

chamber, with or without moisture content 

reduction, until it achieves a minimum core 

temperature of 56 °

C for a minimum of 30 

minutes.

2.13 Kiln dried (KD)-Lumber that has been 

seasoned in a chamber to a predetermined 

moisture content by applying heat.

2.14 Lumber-Lumber is defined as a 

manufactured product derived from a log through 

sawing or planing. [see 3.3]

2.15 Lumber grades-Manufacturing 

categories of lumber that provide the extent and 

limitations of the characteristics permitted in the 

particular grade.

2.16 Nominal size-The label designation for 

lumber size categories that does not reflect the 

dressed size. The nominal size is greater than the 

dressed size, i.e. a dry “2 by 4” is surfaced to 38 

mm by 89 mm (1 1/2 by 3 1/2 inches). 

2.17 Species-The commercial names 

contained in Appendix A for lumber cut from the 

principal botanical species of softwood shall be 

used in the formulation of lumber grading rules 

and in the terms of purchase and sale of ALS 

program lumber.

2.18 Worked lumber (working)-Dressed 

lumber that has also been matched, shiplapped or 

patterned.

3. CLASSIFICATION

3.1 General-ALS program lumber shall be 

classified according to the use, extent-ofmanufacture and nominal size.

3.2 Use

3.2.1 Yard lumber-Lumber of those grades, 

sizes, and patterns intended for ordinary 

construction and building purposes. [see 6.3.1]
4

3.2.2 Structural lumber-Lumber for use 

where design values are required. [see 6.3.2]

3.2.3 Factory and shop lumber-Lumber 

that is produced or selected for remanufacturing 

purposes and intended for non-structural 

applications. [see 6.3.3].

3.3 Extent-of-manufacture

3.3.1 Rough lumber-Lumber which has not 

been dressed (surfaced) but which has been 

sawed, edged and trimmed at least to the extent 

of showing saw or other primary manufacturing 

marks in the wood on the four longitudinal 

surfaces of each piece for its over-all length. 

Lumber surfaced on one edge (S1E), two edges 

(S2E), one side (S1S), or two sides (S2S) is 

classified as rough lumber in the unsurfaced 

width or thickness.

3.3.1.1 Saw-sized lumber-Lumber uniformly 

sawn to the dressed size for surfaced lumber, and 

not planed on the faces, for uses requiring a 

rough texture. When saw sized lumber is grade 

marked it shall be labeled as such.

3.3.1.2 Sized lumber-Lumber uniformly 

manufactured to dressed surfaced sizes. Sized 

lumber may be rough, surfaced or partially 

surfaced on one or more faces. 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 (S1S), two sides (S2S), one edge (S1E), 

two edges (S2E), or a combination of sides and 

edges (S1S1E, S1S2E, S2S1E, S4S). Lumber 

surfaced S1E, S2E, S1S, S2S, S1S1E, S1S2E, 

S2S1E, S4S is classified as dressed (surfaced) 

lumber in the surfaced width or thickness.

3.3.3 Worked lumber-Dressed lumber that 

has also been matched, shiplapped or patterned.

3.3.3.1 Matched (tongue-and-grooved, 

centermatch) lumber-Lumber worked with a 

tongue on one edge of each piece and a groove on 

the opposite edge to provide a close tongue-andgroove 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 

rabbeted 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 

pattern or to a molded form, in addition to being 

dressed, matched, or shiplapped, or any 

combination of these workings.

3.4 Nominal size 

3.4.1 Boards-Lumber of less than nominal 2-

inch thickness and of nominal 2-inch or greater 

width. Lumber of less than nominal 2-inch 

thickness and of less than nominal 6-inch width is 

designated as strips or boards.

3.4.2 Dimension-Lumber from nominal 2-

inch to, but not including, nominal 5-inch 

thickness, and of nominal 2-inch or greater width. 

Dimension is also designated as framing, joists, 

planks, rafters, or studs.

3.4.3 Timbers-Lumber of nominal 5-inch or 

greater in least dimension. Timbers are also 

designated as beams, stringers, posts, caps, sills, 

girders, or purlins.

3.4.4 The dressed sizes of all lumber 

dimensions referenced in this Standard in terms 

of "nominal" sizes are set-out in Tables 1 through 

4. The use of "nominal" sizes in the language of 

this Standard follows the practice of the industry. 

No inferences shall be drawn that the "nominal" 

sizes are dressed sizes. [see 2.16]

4. MEASUREMENT AND TALLY
5

4.1 Tally, standard sizes-Lumber shall be 

tallied board measure or cubic measure. Dressed 

sizes shall be used when lumber is measured by 

cubic measure.

Note: The invoices for dressed lumber of standard 

sizes should show the number of pieces of each 

nominal size and length as well as the actual 

thickness and width of such lumber.

4.2 Tally, nonstandard sizes-Lumber 

finished to nonstandard sizes shall be tallied 

board measure as of either 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 

measured by cubic measure.

Note: The dressed thickness and width of such 

lumber should be shown on the invoice.

4.3 Board rule tally-In lumber specified to 

be measured with a board rule on dressed widths, 

pieces measuring to the even half foot are 

alternately counted as of the next higher and 

lower foot count; fractions below the half foot are 

dropped, and fractions above the half foot are 

counted as of the next higher foot.

4.4 Averages3-length, width-The average 

length in feet of a shipment of lumber is computed 

by dividing the total length in feet by the total 

number of pieces in the shipment. The average 

width in inches of a shipment of lumber of 

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 nominal 1 inch, the total 

board foot tally is divided first by the nominal 

thickness as expressed in inches and fractions of 

an inch.

5. LUMBER SIZES

 3 This computation applies to conventional units.

5.1 Rough size-The minimum rough 

thickness of dry or unseasoned lumber 1 or more 

inches in nominal thickness shall be not less than 

3.2 mm (1/8 inch) thicker than the corresponding 

minimum dressed thickness, except that up to 20 

percent of a shipment shall be not less than 2.4 

mm (3/32 inch) thicker than the corresponding 

minimum dressed thickness. The minimum rough 

widths shall not be less than 3.2 mm (1/8 inch) 

wider than the corresponding minimum dressed 

width.

5.2 Dressed sizes-Dressed sizes of lumber 

shall equal or exceed the minimum sizes shown in 

Tables 1, 2, 3 and 4. Sizes in Tables 1, 2, 3 and 4 

pertain to those items as measured at time of 

manufacture. Lumber will change in dimension 

(shrink or expand) in response to its equilibrium 

moisture content. [see 6.2.3.1 and 6.2.5.1] [see 

also 5.3.1 covering length and 7.3 for grade 

marking nonstandard sizes.]

5.3 Lengths

5.3.1 Standard-Standard lengths of lumber 

shall be in multiples of 0.3048 m (1 foot) or 0.6096 

m (2 feet) as specified in the certified grading 

rules.

5.3.2 Trimmed-Unless otherwise stated in 

the contract of purchase, lumber shall be trimmed 

for the removal of spur and splintered ends, and if 

2 inches or less in nominal thickness (except lath), 

shall be double-end-trimmed to a length that is 

not less than the nominal length and that is not 

more than 76 mm (3 inches) in excess of nominal 

length. The overlength tolerance in nominal 2 

inch dimension over 305 mm (12 inches) wide or 

over 6.1 m (20 feet) in length is 305 mm (12 

inches).

Note: The marketing practice covering lengths of 

lumber should permit the buyer to obtain specified 

lengths or specified assortments of lengths.
6

Table 1. Nominal and minimum-dressed dry sizes of finish, flooring, ceiling, partition, and 

stepping at 19 percent maximum-moisture content.

The thicknesses apply to all widths and all widths apply to all thicknesses except as modified. Sizes are 

given in millimeters and inches. Metric units are based on dressed size. See B1, Appendix 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 shiplapped ceiling of 8 mm (5/16 inch), 11 mm (7/16 

inch), and 14 mm (9/16 inch) dressed thicknesses, the tongue or lap shall be 5 mm (3/16 inch) wide, with the over-all 

widths 5 mm (3/16 inch) wider than the face widths shown in the above table. In all other worked lumber shown in 

this table of dressed thicknesses of 16 mm (5/8 inch) to 32 mm (1-1/4 inches), the tongue shall be 6 mm (1/4 inch) 

wide or wider in tongued-and-grooved lumber, and the lap shall be 10 mm (3/8 inch) wide or wider in shiplapped 

lumber, and the over-all widths shall be not less than the dressed face widths shown in the above table plus the 

width of the tongue or lap.
7

Table 2. Nominal and minimum-dressed dry sizes of siding at 19 percent maximummoisture content.

The thicknesses apply to all widths and all widths apply to all thicknesses. Sizes are given in millimeters 

and inches. Metric units are based on dressed size. See B1, Appendix B for rounding rule for metric units.

Item

Thicknesses Widths

Nominal 

Inch

Minimum Dressed Nominal

Inch

Minimum Dressed

mm inch mm inch

Plain Bevel

1/2

9/16

5/8

3/4

1

11 butt, 5 tip

12 butt, 5 tip

14 butt, 5 tip

17 butt, 5 tip

19 butt, 5 tip

7/16 butt, 3/16 tip

15/32 butt, 3/16 tip

9/16 butt, 3/16 tip

11/16 butt, 3/16 tip

3/4 butt, 3/16 tip

4

5

6

8

10

12

89

114

140

184

235

286

3-1/2

4-1/2

5-1/2

7-1/4

9-1/4

11-1/4

Rabbeted 

Bevel

1/2

3/4

11 butt, 5 tip

17 butt, 7 tip

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)

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)

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)

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)

1 18 a 23/32 a

4

6

8

10

12

76

127

171

222

273

3

5

6-3/4

8-3/4

10-3/4

a Minimum dressed thickness for 1-inch nominal redwood and western red cedar shiplap and tongue and groove siding 

patterns is 17 mm (11/16 inch).
8

Table 3. Nominal and minimum-dressed sizes of boards, dimension, and timbers.

The thicknesses apply to all widths and all widths apply to all thicknesses. Sizes are given in millimeters and inches. 

Metric units are based on dressed size. See B1, Appendix B for rounding rule for metric units.

Item

Thicknesses Widths

Nominal

Inch

Minimum Dressed Nominal

Inch

Minimum Dressed

Dry a Green a Dry a Green a

mm inch mm inch mm inch mm inch

Boards 

3/8

1/2

5/8

3/4

1

1-1/4

1-1/2

8

11

14

16

19

25

32

5/16

7/16

9/16

5/8

3/4

1

1-1/4

9

12

15

17

20

26

33

11/32

15/32

19/32

11/16

25/32

1-1/32

1-9/32

2

3

4

5

6

7

8

9

10

11

12

14

16

38

64

89

114

140

165

184

210

235

260

286

337

387

1-1/2

2-1/2

3-1/2

4-1/2

5-1/2

6-1/2

7-1/4

8-1/4

9-1/4

10-1/4

11-1/4

13-1/4

15-1/4

40

65

90

117

143

168

190

216

241

267

292

343

394

1-9/16

2-9/16

3-9/16

4-5/8

5-5/8

6-5/8

7-1/2

8-1/2

9-1/2

10-1/2

11-1/2

13-1/2

15-1/2

Dimension

2

2-1/2

3

3-1/2

4

4-1/2

38

51

64

76

89

102

1-1/2

2

2-1/2

3

3-1/2

4

40

52

65

78

90

103

1-9/16

2-1/16

2-9/16

3-1/16

3-9/16

4-1/16

2

2 1/2

3

3 1/2

4

4 1/2

5

6

8

10

12

14

16

38

51

64

76

89

102

114

140

184

235

286

337

387

1-1/2

2

2-1/2

3

3-1/2

4

4-1/2

5-1/2

7-1/4

9-1/4

11-1/4

13-1/4

15-1/4

40

52

65

78

90

103

117

143

190

241

292

343

394

1-9/16

2-1/16

2-9/16

3-1/16

3-9/16

4-1/16

4-5/8

5-5/8

7-1/2

9-1/2

11-1/2

13-1/2

15-1/2

Timbers

5 & 6 

thick 13 off 1/2 off 13 off 1/2 off 5 & 6 wide 13 off 1/2 off 13 off 1/2 off

7-15 thick 19 off 3/4 off 13 off 1/2 off 7-15 wide 19 off 3/4 off 13 off 1/2 off

>=16 

thick 25 off 1 off 13 off 1/2 off >= 16 wide 25 off 1 off 13 off 1/2 off

a See 2.7 and 2.11 for the definitions of dry and green lumber.
9

Table 4. Nominal and minimum-dressed sizes of worked lumber.

The thicknesses apply to all widths and all widths apply to all thicknesses. Sizes are given in millimeters and inches. 

Metric units are based on dressed size. See B1, Appendix B for rounding rule for metric units.

Item

Thicknesses Widths

Nominal

Inch

Minimum Dressed Nominal 

Inch

Minimum Dressed

Drya Greena Drya Greena

mm inch mm inch mm inch mm inch

Shiplap,

10 mm (3/8 inch) 

lap

1 19c 3/4c 20 25/32

4

6

8

10

12

14

16

79

130

175

225

276

327

378

3-1/8

5-1/8

6-7/8

8-7/8

10-7/8

12-7/8

14-7/8

81

133

181

232

283

333

384

3-3/16

5-1/4

7-1/8

9-1/8

11-1/8

13-1/8

15-1/8

Shiplap,

13 mm (1/2 inch)

lap b

1

2

2-1/2

3

3-1/2

4

4-1/2

19c

38

51

64

76

89

102

3/4c

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

Centermatch

(Tongue & 

Groove),

6 mm (1/4 inch) 

tongue

1

1-1/4

1-1/2

19c

25

32

3/4c

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 b

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-forSplines

2-1/2

3

3-1/2

4

4-1/2

51

64

76

89

102

2

2-1/2

3

3-1/2

4

52

65

78

90

103

2-1/16

2-9/16

3-1/16

3-9/16

4-1/16

4

6

8

10

12

89

140

184

235

286

3-1/2

5-1/2

7-1/4

9-1/4

11-1/4

90

143

190

241

292

3-9/16

5-5/8

7-1/2

9-1/2

11-1/2

a See 2.7 and 2.11 for the definitions of dry and green lumber.

b In worked lumber of nominal 2-inch and greater thickness, the tongue shall be 10 mm (3/8 inch) wide in tongued-and-grooved 

lumber and the lap shall be 13 mm (1/2 inch) wide in shiplapped lumber, with the over-all widths 10 mm (3/8 inch) and 13 mm 

(1/2 inch) wider, respectively, than the face widths shown in the above table. Double tongued-and-grooved decking shall be 

manufactured with a 10 mm (3/8 inch) or 8 mm (5/16 inch) wide tongue. 

c Alternate minimum dressed dry thickness for 1-inch nominal center-match and shiplap is 18 mm (23/32 inch).
10

6. GRADING RULE REQUIREMENTS

6.1 General concepts

6.1.1 Grading parameters-To the extent to 

which differences in the characteristics of species, 

in the quality of logs, in conditions of manufacture 

and in the uses to which the product is put will 

permit, the basic provisions for the grading of 

lumber shall be uniform. The grading of lumber 

cannot be considered an exact science because it is 

based on either a visual inspection of each piece 

and the judgment of the grader or on the results 

of a method of mechanically determining the 

strength characteristics of structural lumber [see 

6.3.2.2]. Grading rules shall establish a maximum 

of 5 percent below grade as an allowable variation 

between agency qualified graders. If any grading 

rules indicate that a grade qualifies under two use 

classifications, the grade provisions shall satisfy 

the requirements for both classifications.

6.1.2 Minimum grade requirements-The 

method of determining the extent and limitations 

of the characteristics permitted in the poorest 

pieces admissible in each grade of lumber shall be 

stated in a certified rule, except in the lowest 

grade of each classification. Since lumber grades 

are broad manufacturing categories, grades 

overlap and pieces are selected from a grade to 

comprise another grade outside of that grade 

category. A specific shipment shall not be made 

up of only pieces containing characteristics of the 

maximum number or size permitted in the grade.

6.1.3 Grade characteristics-Characteristics 

permitted and limitations for rough lumber shall 

be the same as those prescribed in grading rules 

for dressed lumber of the same grade and, in 

addition, such others as will disappear in 

standard dressing shall be allowed. If 

characteristics other than those described in 

certified grading rules are encountered, they shall 

be evaluated in relation to the characteristics 

permitted or limitations prescribed for the grade 

under consideration and shall be allowed if 

regarded as equivalent or less damaging in effect 

on the strength, appearance, or other utility value 

of the piece. In all grades, the size of allowable 

characteristics shall not exceed that specified in 

the respective grading rules.

Note: In many grades, the size of permitted 

characteristics 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 conforms 

to the requirements of such special provisions as 

well as to the regular grade designated, it shall 

be regarded as of standard quality.

6.1.5 Mixed grades-Mixed grades other than 

the two highest established grades for each 

grading rule category shall not be included in 

certified grading rules.

6.1.6 Nonstandard grades-When 

nonstandard grades, sizes, or patterns are 

specified, or when particular provisions of a 

standard grade are waived or changed, inspection 

shall be made accordingly, but all of the other 

provisions of the certified grading rules shall 

apply.

6.2 Seasoning provisions

6.2.1 General-The grading rules shall include 

provisions regulating lumber seasoning and 

moisture content. The provisions shall be 

developed by each geographical region for each 

species based on its own conditions and the 

requirements of the users of its products subject 

to the other provisions of Section 6. Provisions 

shall be expressed in terms of maximum moisture 

content allowed in each piece of lumber and 

determined in accordance with ASTM D 4444 

Standard Test Method for Laboratory 

Standardization and Calibration of Hand-Held 

Moisture Meters and ASTM D 7438 Standard 

Practice for Field Calibration and Application of 
11

Hand-Held Moisture Meters as appropriate. The 

restrictions on the moisture content of seasoned 

lumber shall apply at the time of shipment, at the 

time of dressing (if dressed lumber is involved), 

and at the time of any reinspection (if moisture 

content is involved in the reinspection), as 

provided in the applicable grading rules.

6.2.2 Grading rules-The grading rules for 

each species or region shall include clear 

definitions for dry lumber under nominal 5-inch 

thickness [see 2.7]. The definitions shall be based 

on a maximum moisture content of 19 percent or 

less. The choice to grade and grade mark any 

item as green ALS program lumber or dry ALS 

program lumber shall be determined by each 

rules writing agency in accordance with its own 

conditions [see 2.7, 2.11, and 2.13].

6.2.3 Dry size requirements-The grading 

rules shall require lumber under nominal 5-inch 

thickness sold as dry to be 19 percent or less in 

moisture content at the time of dressing, and to be 

not less than ALS minimum dry dressed 

thickness and width at 19 percent moisture 

content, or at such lower maximum-moisture 

content as may be applicable to the lumber at the 

time of dressing. The minimum-dressed dry sizes 

are shown in tables 1, 2, 3 and 4.

6.2.3.1 Shrinkage or expansion from dry 

size-Shrinkage or expansion that occurs after 

dressing to standard dry size shall be recognized 

through the allowance of a tolerance below or 

above minimum standard dry sizes on a basis of 

1 percent shrinkage or expansion for each four 

percentage points of moisture content change or 

0.7 percent shrinkage or expansion for each four 

percentage points of moisture content change for 

Redwood, Western Red Cedar, and Northern 

White Cedar. The shrinkage or expansion 

percentages are average values. Shrinkage or 

expansion of individual pieces may vary.4

Shrinkage allowances are determined assuming 

maximum allowable moisture content at the time 

of surfacing. Expansion allowances are 

determined assuming a typical equilibrium 

moisture content or other suitable reference 

moisture content.

6.2.4 Size differentials-When the grading 

rules in any region permit lumber less than 

nominal 5-inch thickness to be dressed green, the 

rules shall require that the lumber be dressed to 

sizes specifically stated according to both 

thickness and width, as set forth in tables 3 and 4.

6.2.5 Green size requirements-The 

minimum dressed green sizes specifically stated 

in the rules shall be not less than the green sizes5

 

4 The range of shrinkage of individual pieces from 

experimental observation is from 2% to 7%. Variables 

that affect measurement and shrinkage of lumber are: 

density, species, grain orientation and allowable grade 

characteristics. See Forest Products Laboratory 

Research Reports 15 and 30.

shown in tables 3 and 4, except for Redwood, 

Western Red Cedar, and Northern White Cedar. 

For these three species, the following minimum 

dressed green thicknesses shall apply: 17 mm 

(21/32 inch) for corresponding nominal 3/4 inch 

dry, 20 mm (25/32 inch) for nominal 1-inch, 40 

mm (1-9/16 inch) for nominal 2-inch, 52 mm (2-

1/16 inch) for nominal 2-1/2 inch, 65 mm (2-9/16 

inch) for nominal 3-inch, 78 mm (3-1/16 inch) for 

nominal 3-1/2 inch, 90 mm (3-9/16 inch) for 

nominal 4-inch, and 103 mm (4-1/16 inch) for 

nominal 4-1/2 inch. The following minimum green 

dressed widths shall apply: 65 mm (2-9/16 inch) 

and 90 mm (3-9/16 inch) for nominal 3-inch and 4-

inch, 116 mm (4-9/16 inch), 141 mm (5-9/16 inch), 

5 The minimum green sizes are based on shrinkage factors 

of 2.35 percent in thickness and 2.80 percent in width 

from the fiber saturation point to a 19 percent 

maximum moisture content with recognition given to 

manufacturing practices and the differences in 

shrinkage characteristics between species of lumber or 

species groups of lumber.
12

and 167 mm (6-9/16 inch) for nominal 5-inch, 6-

inch, and 7-inch, 187 mm (7-3/8 inch), 238 mm (9-

3/8 inch), 289 mm (11-3/8 inch) for nominal 8-inch, 

10-inch, and 12-inch, 341 mm (13-7/16 inch) and 

392 mm (15-7/16 inch) for nominal 14-inch and 

16-inch.

6.2.5.1 Shrinkage or expansion from green 

size-Shrinkage that occurs after dressing to 

standard green size shall be recognized through 

the allowance of a tolerance below minimum 

standard green sizes on a basis of 1 percent 

shrinkage for each four percentage points of 

moisture content below 30 percent or 0.7 percent 

shrinkage for each four percentage points of 

moisture content below 30 percent for Redwood, 

Western Red Cedar, and Northern White Cedar. 

Expansion allowances are determined assuming 

a typical equilibrium moisture content or other 

suitable reference moisture content. The 

shrinkage or expansion percentages are average 

values. Shrinkage or expansion of individual 

pieces may vary.6

6.2.6 Grade marking (grade stamping)-

Grading rules that provide for grade marking of 

lumber less than nominal 5-inch thickness shall 

contain a provision for standardized marking so 

as to indicate whether the lumber was green or 

dry at time of dressing. The standardized mark 

shall be S-GRN if surfaced green, S-DRY if 

surfaced dry, or KD if kiln dried to a maximum 

moisture content of 19 percent at time of 

surfacing. Moisture-content limits of less than 19 

percent maximum moisture-content for dry or kiln 

dried shall only be specified if included in rules 

certified by the Board. For lumber of nominal 5-

inch or greater thickness, other moisture-content 

 

6 The range of shrinkage of individual pieces from 

experimental observation is from 2% to 7%. Variables 

that affect measurement and shrinkage of lumber are: 

density, species, grain orientation and allowable grade 

characteristics. See Forest Products Laboratory 

Research Reports 15 and 30.

limits shall be specified only if included in rules 

certified by the Board.

6.3 Use classification provisions for 

visual grading

6.3.1 Yard lumber

6.3.1.1 Grade classifications-The grading of 

surfaced yard lumber is based upon the uses for 

which the particular grade is designed and is 

applied to each kind with reference to its size and 

length when graded without consideration to 

further manufacture. On the basis of quality, the 

basic grade classifications of yard lumber shall be 

as follows:

(a) Select: Lumber for natural and paint 

finishes.

(b) Common: Lumber for general 

construction and utility purposes.

6.3.1.2 Yard lumber sizes-The dressed 

thicknesses and widths of yard lumber as 

specified in 3.4, 5.1 and 5.2 shall be considered as 

minimum standards for the corresponding 

nominal sizes as shown.

Note: Lumber of standard size, rough or dressed, 

may be described by its nominal dimension 

providing dressed sizes are shown on invoices and 

other documents.

6.3.1.3 Bundled lumber-Each length of 

bundled lumber, except end-matched lumber, 

beveled siding, and bungalow siding shall be 

bundled separately unless otherwise specified.

6.3.1.4 Finish and boards-In shipments of 

rough finish/selects and boards, pieces 13 mm (1/2 

inch) or greater than the nominal inch-unit 

thickness, such as are produced by uneven 

sawing, shall, at the option of the buyer, be 

rejected or be accepted as of the next lower grade.

6.3.1.5 Grading faces-Yard lumber other than 

timbers and dimension [see 6.3.2.3] shall be 
13

graded from the face or best side only unless 

otherwise specified.

6.3.1.6 Fencing – Sawn boards used in the 

construction of fences may be square-top, dogeared, square-edge or tongue and groove. The 

tolerance in sawing of such boards shall not 

exceed 1.6 mm (1/16 inch) over or under the 

invoice thickness.

6.3.2 Structural lumber

6.3.2.1 Development of design values-Design 

values contained in grading rules shall be 

developed in accordance with appropriate ASTM 

standards and other technically sound criteria. 

The National Institute of Standards and 

Technology, with the advice and counsel of the 

U.S. Forest Products Laboratory, shall be the final 

authority as to the appropriateness of such 

standards or criteria. The Board shall seek the 

assistance of the U.S. Forest Products Laboratory 

in reviewing design values set forth in grading 

rules and, in the case of each set of grading rules 

submitted for certification, the Board shall obtain 

a report from the Laboratory to verify that the 

procedures used in developing the claimed values 

are in accordance with the standards and criteria 

described herein. Rules-writing agencies shall 

make available upon request an explanation of 

the means by which the claimed values were 

derived. When more than one rules-writing 

agency has responsibility for writing grading rules 

for a given species, a group of species, or a 

geographical subdivision of a species or of a group 

of species, a common set of strength and stiffness 

values shall be used by the agencies involved for 

that species, subdivision, or group of species in the 

interest of uniformity and standardization.

6.3.2.2 Grading-mechanical-The grading of 

structural lumber by mechanical means is 

recognized as an acceptable method of grading. 

When graded by mechanical means all such 

grading equipment and methods shall be subject 

to approval and certification by the Board.

6.3.2.3 Grading faces-Timbers and dimension 

shall be graded from all four faces.

6.3.3 Factory and shop lumber

6.3.3.1 Grade classification-The grade 

classifications of factory and shop lumber shall be 

those promulgated by the agencies which 

formulate and publish grading rules and which 

have been certified by the Board.

6.3.3.2 Grade characteristics-Factory and 

shop lumber shall be graded with reference to its 

use for doors and sashes, or on the basis of 

characteristics affecting its use for general cutup 

purposes, or on the basis of size of cutting. Its 

grade shall be determined by the percentage of 

the area of each board or plank available in 

cuttings of specified or of given minimum size and 

qualities and shall be determined from the poor 

face based on the quality 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 

certified by the Board.

6.3.3.4 Warped lumber-The cuttings in warped 

lumber shall be so laid out as to surface two sides 

to standard thickness and have straight edges 

parallel to the edges of the board or plank.

7. GRADE MARKING (GRADE STAMPING)

7.1 Agency procedures-Each accredited 

agency shall submit procedures with respect to 

grade marking to the Board for approval.

7.2 Agency symbol-Each accredited agency 

shall maintain a bona fide supervisory inspection 

service under which each mill authorized to use 
14

the registered symbol of the accredited agency7 in 

conjunction with the grade mark will be inspected 

regularly as to grading efficiency and conformity 

to all the agency established rules for grade 

marking.

7.3 The Grade mark (grade stamp)-When 

ALS program lumber is grade marked, the grade 

marking shall be subject to the following 

provisions:

7.3.1 The grade mark shall signify that the 

lumber conforms to the size, grade and seasoning 

provisions of the rules under which it is graded. 

When green lumber of less than nominal 5-inch 

thickness is graded and grade marked under the 

applicable grading rules [see also 6.2.6], it shall 

comply with the green size requirements of such 

rules. If lumber is dressed to a size below the 

minimum size requirements shown in Tables 1-4 

or below the minimum sizes set forth in the 

applicable grading rules, the mark shall show 

that size, and if less than of nominal 5-inch 

thickness, shall state whether the lumber was dry 

or green when dressed.

7.3.2 A distinguishable mark or insignia, 

registered and symbolizing grading supervision by 

an accredited agency, shall be used in conjunction 

with the grade mark for each agency. Facsimiles 

of the grade marks of the grading and inspection 

agencies that are accredited shall be available to 

specifiers, purchasers and consumers.8

7.3.3 All pieces and/or bundles of a given grade 

shall be grade marked. Bundled lumber is 

defined as a small number of boards or strips 

 

7 Facsimiles of the grade marks of the grading and 

inspection agencies that are accredited by the Board of 

the ALSC, Incorporated, are available on the web at 

www.alsc.org or from the ALSC, Incorporated, P.O. Box 

210, Germantown, MD 20875-0210. Telephone (301) 

972-1700, Fax (301) 540-8004.

8 Ibid.

bound by some method, such as shrink wrap, 

string or similar binding, so as to form a small

package.

7.3.3.1 Except for bundled lumber, the mixing of 

grade marked and non-grade marked lumber in 

the same package shall not be permitted. 

7.3.4 Mixed grades, other than the two highest 

recognized grades for each grading rule category, 

shall not be grade marked with a combination 

grade designation. 

7.3.5 The grade mark for lumber shall include 

an identification or designation of the commercial 

name of the species [see Appendix A] from which 

the lumber was produced. The identification of 

species shall not be required when the agency 

symbol also indicates the species from which the 

lumber was produced. Where grading rules 

contain 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 assigned to the 

group.

7.3.6 These provisions are not intended to 

preclude the inclusion of additional regulations by 

an agency regarding the use of its grade mark 

provided the basic provisions of this section are 

observed. 

7.3.7 Remanufacture (ripped, resawn or 

surfaced) of graded or grade marked lumber 

negates the grade or grade mark and the design 

values of the original product.

7.3.7.1 When grade marked dimension lumber is 

resawn or remanufactured in such a way as to 

potentially alter the grade indicated by the grade 

mark, the original grade mark shall be 

obliterated.

8. INSPECTION AND REINSPECTION

8.1 Inspection
15

8.1.1 Agency certification and 

supervision-When ALS program lumber is grade 

marked, the grade marking shall be under the 

direction, including regular grading supervision at 

mills, of an agency accredited by the Board as 

being competent and having adequate facilities for 

such supervision.

8.1.2 Delegation of grading authorityPermission to grade mark shall be delegated only 

by an agency accredited by the Board to operate a 

mill supervisory service to those mills which have 

demonstrated and proven their ability to conform 

to and are currently in conformance with the 

grading rules for the species and grades which 

they manufacture. The mill shall also agree to 

maintain the established standards of size and 

grade and to submit its lumber to inspection by 

the supervisory agency both at the mill and upon 

complaint at destination.

8.1.3 Payment-certificate costs-When an 

accredited agency issues a certificate on a 

shipment, the party requesting the certificate 

shall pay for the cost thereof.

8.1.4 Service-Inspection service shall be 

required for the inspection of grades not described 

in the rules only when written detailed 

specifications accompany the request for such 

inspection. For the inspection of standard grades 

in nonstandard sizes, inspection service shall be 

required based on 6.1.6 unless otherwise 

prescribed in the contract of purchase and sale.

8.2 Reinspection

8.2.1 General-Subject to freedom of 

agreement between buyer and seller as to the 

settlement of complaints, the purchase, sale, or 

shipment of ALS program grades of lumber shall 

be construed as involving agreement to submit 

lumber to reinspection by an accredited inspection 

agency under published rules by which the 

lumber was graded [see 8.2.4]. Grading rules shall 

include provisions for reinspection in case of 

complaint, and reinspection shall be available to 

anyone at reasonable cost.

8.2.2 Complaints-Grade complaints on 

lumber shall be recognized only when the lumber 

is in the form in which it was shipped. Any 

subsequent change in manufacture, working, or 

through kiln-drying shall relieve the seller of 

responsibility for any grade complaints.

8.2.3 Buyer's responsibilities-In case of a 

complaint, the buyer shall accept that portion of 

the shipment that is of the grade, size, and 

moisture content specified and shall hold intact 

that portion which is disputed for inspection or 

reinspection. Any action on the part of the buyer 

in accepting and using such portion of the 

shipment that is of the grade, size, and moisture 

content specified shall not be construed as the 

acceptance of the entire shipment. The buyer 

shall hold the disputed lumber intact, properly 

protected, for not more than 30 days after the date 

of the request for inspection or reinspection. The 

buyer shall file a complaint with the seller within 

the time specified in 8.2.6 and 8.2.7. The buyer 

shall pay in accordance with the terms of the sale 

for that portion accepted, but acceptance of a part 

of a shipment does not prejudice the buyer’s just 

claims that any unused lumber does not meet the 

specifications of the grade, size, or moisture 

content.

8.2.4 Seller's responsibilities-Upon receipt 

of a complaint from the purchaser, the seller shall 

immediately request the agency under whose 

rules shipment has been made, or such other 

agency that was agreed upon, to provide 

inspection, reinspection or retally as required 

according to the grading rules in effect at the time 

of execution of the contract.

8.2.5 Cost and assistance-The expense of 

such inspection, reinspection, or retally shall be 

borne in accordance with the inspection provisions 

of the applicable grading rules, but the person 
16

calling for the reinspection shall be responsible to 

the agency for the costs thereof. The purchaser 

shall lend all reasonable assistance to facilitate 

the inspection, reinspection or retally.

8.2.6 Tally, grade, and size complaints-In 

case of a complaint involving tally, the entire item 

shall be held intact for retally. In case of a 

complaint regarding grade or size, but not 

involving tally, the buyer shall hold intact that 

portion of the item that is of the grade or size 

which is in dispute for inspection and shall file 

complaint with the seller within 10 days of date of 

receipt of the shipment.

8.2.7 Moisture content complaints-In case 

of a complaint involving moisture content, the 

buyer shall inform the seller of the complaint 

within 72 hours after the lumber is unloaded. In 

such cases, the seller shall answer such complaint 

within 72 hours from receipt of complaint. A 

reinspection involving a complaint on moisture 

content shall be made in accordance with the 

provisions of the applicable grading rules. Each 

piece shall be tested for moisture content, and 

separation shall be made of all pieces conforming 

to the maximum allowable moisture content from 

any portion exceeding such maximum.

8.2.8 Reinspection results-Each item of a 

shipment shall be considered as of the grade 

invoiced if, upon reinspection under the grading 

rules under which the lumber was graded and 

sold, 95 percent or more thereof is found to be of 

said grade or better. When degrades in grade or 

moisture content or both are in excess of 5 percent 

of the board footage of each item, or when they are 

more than one grade lower than the grade invoice, 

such degrades shall be kept separate and shall be 

the property of the seller unless otherwise agreed. 

These provisions shall not apply in the case of 

specially worked lumber.

9. AMERICAN LUMBER STANDARD 

COMMITTEE

9.1 Functions of ALSC-The functions of 

the ALSC shall be:

9.1.1 To act as the Standing Committee for the 

purpose of considering proposals for future 

revisions of or amendments to this Standard.

When acting as the Standing Committee, the 

procedures for the development of Voluntary 

Products Standards of the US Department of 

Commerce shall be applicable. The Department of 

Commerce shall provide the secretariat and 

appoint a chairman for the Standing Committee.

9.1.2 To cooperate with the U.S. Department 

of Commerce in establishing and making 

continuously available basic standards for lumber 

size, pattern, quality, inspection, and reinspection 

for use by industry and trade.

9.1.3 To determine the criteria by which the 

Board shall adjudge and approve the following as 

being in conformance with this Standard:

9.1.3.1 Any published rules.

9.1.3.2 The competency, reliability, and 

adequacy of the facilities provided by agencies 

publishing grading rules for the purpose of lumber 

certification, inspection, reinspection, and 

supervision of grade marking.

9.1.3.3 The competency, reliability, and 

adequacy of the facilities provided by non-rules 

writing agencies participating in this program 

that do not publish grading rules.

9.1.4 To advise the Board with respect to the 

interpretation or application of this Standard and 

the detailed requirements defined and established 

by the ALSC.

9.1.5 To fix, after consultation with the 

agencies participating in the use of its facilities, 

such charges and fees as the ALSC finds to be 

necessary to cover the actual cost, including 

reserves and provisions for contingencies, of 
17

carrying out its functions, those of the Board, and 

the NGRC. Such charges and fees shall be 

assessed at a uniform proportionate rate against 

the agencies participating in the use of the 

facilities of the ALSC. The accreditation of any 

agency not paying its assessment within 60 days 

after notification by the Secretary of the ALSC 

shall be revoked by the Board.

9.2 Appointment of members-The 

principal and alternate members shall be 

appointed by the Secretary of Commerce for terms 

of not less than two nor more than five years.

9.3 Composition of ALSC-The following 

procedures shall apply in making appointments to 

the ALSC.

9.3.1 A rules-writing agency is one that 

participates in this program and that formulates, 

publishes, and maintains grading rules and 

maintains inspection facilities covering the 

various lumber species. Each rules-writing agency 

may nominate a principal and alternate for each 

member allotted to that agency. Principal 

members and their alternates shall be appointed 

from the nominees furnished by each agency as 

follows:

Agency Members

Allotted

Southern Pine Inspection Bureau 2

Western Wood Products Association 2

West Coast Lumber Inspection Bureau 2

Redwood Inspection Service 1

Northeastern Lumber Manufacturers

Association 1

Northern Softwood Lumber Bureau 1

National Lumber Grades Authority 1

Each other agency qualifying under

this category 1

9.3.2 A non-rules writing agency is one that 

participates in this program and that does not 

publish grading rules. Each non-rules writing 

agency may nominate a principal and alternate 

member. Three principal members and their 

alternates shall be appointed from among the 

nominees so furnished.

9.3.3 Firms or organizations within lumber 

specifying, distributing, and consuming groups, at 

the request of the Secretary of Commerce, may 

nominate a principal and an alternate for each 

member allotted. Principal members and their 

alternates shall be appointed from those groups as 

follows:

Groups Members

Allotted

Lumber Distributors & Wholesalers 2

Lumber Retailers 2

Wood Using Industries 2

General Contractors 1

Home Builders 1

Architects 1

Engineers 1

Wood Treating Industry 1

9.3.4 The Secretary of Commerce may appoint 

consumer-at-large principal members and their 

alternates to represent the general public.

9.3.5 Each nomination shall be submitted to 

the Secretary of Commerce by the appropriate 

agency, firm, or organization upon request or 

whenever a vacancy occurs in the segment 

represented. Each nomination shall contain the 

following:

9.3.5.1 A summary of the qualifications of the 

nominee.

9.3.5.2 A statement of the method or procedure 

by which the nominee was selected and the 

procedures under which the nominee will exercise 

the responsibility of membership for the agency or 

industry segment represented. 
18

9.3.5.3 A statement of any interests, financial or 

otherwise, which the nominee has in agencies or

segments of the industry other than the one the 

nominee represents.

9.3.5.4 For agencies submitting more than one 

nominee, a listing in the order of priority for 

appointment.

9.3.6 Ex officio, non-voting principal and 

alternate members may be appointed by the

Secretary of Commerce from the following Federal 

agencies:

Department of Defense

Department of Agriculture

Department of Interior

General Services Administration

Department of Housing & Urban Development 

National Institute of Standards & Technology

9.3.7 Balance of representation-Upon 

request, the Secretary of Commerce may consider 

making changes in the constitution of the ALSC 

or making additional appointments to ensure that 

the ALSC has a balance of interest and is not 

dominated by a single interest category. In such 

considerations, the Secretary of Commerce shall 

consult the ALSC for advice regarding balance 

and the criteria by which it may be determined.

9.4 ALSC secretary-Except as provided in 

9.1.1, the manager or executive officer of the 

Board, employed as provided in 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 maintain 

inspection facilities, together with a majority of 

the other members, shall constitute a quorum for 

the transaction of business. A vote of the majority 

of those present shall decide any question that 

comes before a meeting; but if at any meeting of 

the ALSC there shall be less than a quorum 

present, a majority of those present shall adjourn 

the meeting or act on the subjects before it, 

subject to ratification in writing by the respective 

majorities which constitute a quorum.

9.5.2 Correspondence-Business that has not 

been previously presented at a meeting of the 

ALSC shall be held until the next meeting or 

transacted by correspondence in accordance with 

rules to be established by the ALSC.

10. BOARD OF REVIEW

10.1 Autonomy of Board-The Board shall 

be an autonomous body functioning under by-laws 

approved by the ALSC and consistent with 

Section 10.

10.2 Composition, election, terms, 

compensation, and removal-The Board shall 

be composed of three members, none of whom 

shall be members of the ALSC or affiliated with 

an accredited agency or any member of an 

accredited agency.

10.2.1 The chairman of the ALSC shall appoint 

a spokesperson for each of the three membership 

groups within the ALSC that shall nominate 

members of the Board. The spokesperson shall 

determine and report the decision of the group to 

the Chairman along with a summary of the 

qualifications of each nominee and a statement of 

any interests, financial or otherwise, which the 

nominee has in the lumber industry. Board 

members shall be nominated as follows:

10.2.1.1 One member by majority decision of 

those ALSC members representing the accredited 

rules-writing agencies.

10.2.1.2 One member by majority decision of 

those members representing the accredited nonrules-writing lumber inspection agencies.
19

10.2.1.3 One member by majority decision of 

those remaining ALSC members representing 

other interests.

10.2.1.4 The names of the nominees shall be 

submitted to the Department of Commerce prior 

to election and shall be accompanied by a 

summary of the qualifications of each nominee 

and an attestation that the requirements of 10.2 

and 10.2.1 have been met.

10.2.2 Election-Board members shall be 

elected from among the aforesaid nominees by the 

members of the ALSC by a majority of those 

voting. In the event that a nominee designated 

under 10.2.1.1, 10.2.1.2 or 10.2.1.3 fails to receive 

a majority of the votes cast at any election, a new 

nominee shall be designated in accordance with 

the procedure set forth in 10.2.1.1, 10.2.1.2 or 

10.2.1.3.

10.2.3 Terms-The three members of the Board 

shall be elected for terms, respectively, of three 

years, two years, and one year, or until their 

successors are duly elected. Annually thereafter, 

one member shall be elected for a term of three 

years or until a successor is duly elected. 

Vacancies on the Board by reason of death, 

resignation, or removal shall be filled at any 

regularly called ALSC meeting subject to the 

provisions of 10.2.1, 10.2.2 and 9.5.2. Any person 

elected to fill a vacancy shall serve the unexpired 

term of the predecessor.

10.2.4 Compensation-The ALSC shall fix and 

pay compensation to the members of the Board 

and shall reimburse them for all reasonable 

expenses incurred in fulfilling their duties.

10.2.5 Removal-The removal of any Board 

member shall require a vote of not less than twothirds of all the members of the ALSC, with the 

concurrence of the Department of Commerce.

10.3 Board manager-The Board shall select 

and employ a salaried manager or other executive 

officer, subject to the approval of the ALSC, who 

shall assume the responsibilities and perform the 

duties delegated by the ALSC or the Board. Such 

manager or executive officer shall not be in the 

employment of any lumber organization, 

company, or inspection agency while employed by 

the Board.

10.4 Certification functions-Upon 

application, the Board shall examine and certify 

the following as conforming to the requirements of 

this Standard and to additional detailed 

requirements established by the ALSC: Grade 

strength ratios, nomenclature, descriptions of 

grades published by the NGRC and grading rules 

published by accredited, competent and reliable 

agencies having adequate facilities for mill 

inspection and for reinspection of lumber 

(provided that no such rules for any species in any 

region shall be certified if certified published rules 

and service applicable thereto are adequate and 

already fully and fairly available to all 

manufacturers, distributors, and consumers of 

such lumber, on equal terms and conditions 

without discrimination). Certification shall be 

subject to these conditions:

10.4.1 Rules conform to the basic requirements 

of this Standard.

10.4.2 Published rules carry specific references 

to such certification.

10.4.3 The originating agency shall make the 

rules fully and fairly available to all 

manufacturers, distributors, users, and 

consumers of lumber on equal terms and 

conditions and without discrimination.

10.4.4 Subsequent revisions made by the 

promulgating agency to grading rules that have 

been certified by the Board shall be acted upon 

within 90 days after submission to the Board.

10.4.5 Grading rules of an agency shall not be 

certified as conforming to this Standard if the 
20

Board determines the dimension lumber rules 

therein fail to conform to the provisions of the 

National Grading Rule for dimension lumber 

established pursuant to Section 11 of this 

Standard.

10.5 Accreditation functions-Upon 

application, the Board shall examine and accredit 

rules-writing agencies and non-rules-writing 

agencies as conforming to the requirements of this 

Standard and to additional requirements 

established by the ALSC. Accreditation shall be 

subject to these conditions:

10.5.1 The competency, reliability, and 

adequacy of the facilities provided by agencies 

participating in this program for the purposes of 

lumber certification, inspection, reinspection, or 

supervision of grade marking.

10.5.2 The adequacy of the procedure followed 

in authorizing mills to grade mark when 

providing adequate supervisory service. 

10.5.3 The continuing conformance of grading

rules to this Standard.

10.5.4 The continuing competency and 

adequacy of performance of agencies.

10.6 Withdrawal of accreditation-If at any 

time the practices of any accredited agency are 

found not in conformity with this Standard and 

other requirements adopted by the ALSC, and if, 

after due notice in writing to that effect, according 

to established procedures, those practices shall 

not have been brought into conformity with such 

standards and other requirements by the agency 

concerned, the Board is empowered to revoke all 

previous accreditation granted that agency.

10.7 Actions of Board-In all actions in 

relation to the certification of grading rules, 

accreditation of agencies and inspection facilities, 

and grade marking practices, the Board shall 

proceed in a fair and nondiscriminatory manner 

giving full and due consideration to the past 

experience and performance of agencies seeking 

accreditation, and shall apply uniform standards 

of judgment in making all determinations. In the 

matter of inspection agencies, definite 

requirements as to the integrity, competency and 

adequacy of the agency, and the adequacy of its 

facilities shall be established, but all such 

requirements shall be uniformly applied with 

respect to all agencies seeking accreditation from

the Board. No inspection agency that is controlled 

by any person or firm whose own products are 

subject to its inspection and certification shall be 

accredited. Inspection services furnished by 

buyers and users for inspection of their own 

purchases shall not be accredited by the Board.

10.8 Availability of Board-The facilities of 

the Board shall be available at all times on equal 

terms to any affected party. The Board's facilities 

shall also be available to all lumber inspection 

agencies, without favor or discrimination and 

without any requirement for joining or otherwise 

subscribing to any trade association or supporting 

any service or activity other than those of grading, 

standardization, grade marking, and inspection 

that fall within the jurisdiction of the Board.

10.9 Enforcement-The Board shall adopt, 

subject to prior approval by the ALSC, and 

administer rules, regulations, and sanctions to 

ensure the continued competency, reliability, and 

integrity of accredited agencies providing 

inspection services.

10.10 Board hearings-Any party affected by a 

decision or action of the Board shall have the 

right to require the Board to hold a hearing at 

which such party may appear personally or be 

represented by counsel to present supporting 

evidence and argument of the party's position in 

accordance with procedures established by the 

Board.
21

10.11 Reports of action-The Board shall 

within 30 days following an official action make 

such official action public.

11. NATIONAL GRADING RULE 

COMMITTEE

11.1 Autonomy of NGRC-The National 

Grading Rule Committee (NGRC) shall be an 

autonomous body functioning under by-laws 

(providing, among other things, for the 

appointment of subcommittees) approved by the 

ALSC. The bylaws shall be reviewed at least 

every 5 years and reaffirmed or revised, as 

appropriate.

11.2 Functions of the NGRC-The NGRC 

shall establish, maintain, and make fully and 

fairly available grade-strength ratios, 

nomenclature, and descriptions of grades for 

dimension lumber conforming to this Standard. 

Grading rules of an agency shall not be certified 

as conforming to this Standard if the Board 

determines that the dimension lumber rules 

therein fail to conform to the provisions of the 

National Grading Rule for dimension lumber 

established pursuant to this section.

11.3 Composition of NGRC-In the interest 

of obtaining balanced views, the NGRC shall be 

composed of persons representing the following 

that desire to participate:

Organization Number of

Members

Southern Pine Inspection Bureau 2

Western Wood Products Association 2

West Coast Lumber Inspection Bureau 2

Redwood Inspection Service 1

Northeastern Lumber Manufacturers

Association, Inc. 1

Northern Softwood Lumber Bureau 1

International Code Council 1

National Fire Protection Association 1

National Association of Home Builders 1

Canadian Inspection Agencies 1

American Society of Civil Engineers 1

American Institute of Architects 1

Consumer Organizations 1

Lumber Wholesalers 1

Lumber Retailers 1

U.S. Non-rules Writing Agencies 2

Ex officio, non-voting members shall be appointed 

from the following Federal agencies that desire to 

participate:

Department of Housing and Urban

Development 1

Defense Logistics Agency 1

Forest Products Laboratory 1

National Institute of Standards and

Technology 1

11.4 Appointment of members and 

chairman-Members of the NGRC shall be 

competent in the field of lumber technology. Every 

five years each organization or group of 

organizations desiring to participate and entitled 

to representation shall appoint a principal 

member and alternate for each member to which 

it is entitled. The ALSC shall appoint the 

principal member and alternate representing 

consumer organizations. The Chairman of the 

NGRC shall be elected every 5 years by the NGRC 

from among its members.

11.5 Transaction of business-A majority of 

members representing rules-writing agencies and 

a majority of the other members shall constitute a 

quorum to conduct business. Each member shall 

have one vote. The majority vote of those present 

and voting at a meeting shall prevail.

12. REFERENCES
22

12.1 ASTM Standards9

D9-87(1999)e1 Standard Terminology Relating to 

Wood

D1165-03 Standard Nomenclature of Domestic 

Hardwoods and Softwoods

ASTM D4444 - 08 Standard Test Method for 

Laboratory Standardization and 

Calibration of Hand-Held Moisture Meters

ASTM D7438 - 08 Standard Practice for Field 

Calibration and Application of Hand-Held 

Moisture Meters

SI10-02 IEEE/ASTM SI 10 American National 

Standard for Use of the International 

System of Units (SI): The Modern Metric 

System

12.2 Other publications

Comstock, G. L., Shrinkage of coast-type Douglasfir and old-growth Redwood Boards, 

Forest Products Laboratory Research 

Paper 30 (FPL-RP-30), Forest Service, 

U.S. Department of Agriculture, 

Washington, DC 20090-6090, 1965.

Little, Elbert, Jr., Checklist of United States trees 

(Native and Naturalized), Agriculture 

Handbook No. 541, Forest Service, U.S. 

Department of Agriculture, Washington 

DC 20090-6090, 1979.

Wood, Lyman W.; Soltis, Lawrence A., Stiffness 

and shrinkage of green and dry joists, 

Forest Products Laboratory Research 

Paper 15 (FPL-RP-15), Forest Service, 

U.S. Department of Agriculture, 

Washington, DC 20090-6090, 1964.

 

9 ASTM Standards are available from ASTM International, 

100 Barr Harbor Drive, West Conshohocken, PA 19248-

2959; telephone (610) 832-9500; www.astm.org.
23

APPENDIX A COMMERCIAL NAMES OF THE PRINCIPAL SOFTWOOD SPECIES

The commercial names listed below are intended to provide a correlation between commercial names 

for lumber and the botanical names of the species from which the lumber is to be manufactured. In 

some instances more than one species is associated with a single commercial name. For stress-graded 

lumber, the species to be associated with a commercial name will be determined in accordance with 

6.3.2.1. These commercial names are to be used in grading rule descriptions and in specifications [see 

2.15]. The provisions of this Standard apply to lumber manufactured from hardwood species or lumber 

manufactured from foreign species when the species is included in rules certified by the Board of 

Review. The information contained herein is a partial list of commercial names of the principal 

softwood species and species groups. Additional species and species groups are provided in ASTM 

Standard D 1165-03 and the rules certified by the Board of Review.

Commercial Official Common

Species or Species Group Names10 Tree Names11

CEDAR:

Botanical Names

Alaska Cedar Alaska-cedar Chamaecyparis

nootkatensis

Incense Cedar incense-cedar Libocedrus decurrens

Port Orford Cedar Port-Orford-cedar Chamaecyparis

lawsoniana

Eastern Red Cedar eastern redcedar Juniperus virginiana

southern redcedar J. silicicola

Western Red Cedar western redcedar Thuja plicata

Northern White Cedar northern white-cedar T. occidentalis

Southern White Cedar Atlantic white-cedar Chamaecyparis thyoides

CYPRESS12

Baldcypress baldcypress Taxodium distichum

Pond cypress pond cypress T. distichum var. nutans

FIR:

Balsam Fir13

Fraser Fir Fraser fir A. fraseri

balsam fir Abies balsamea

Douglas Fir14

 10 The commercial names for species represent those commonly accepted. Some grading rules certified by the Board provide 

for the inclusion of additional species under the established names.

Douglas-fir Pseudotsuga menziesii

11 The official common tree names conform to the Checklist of United States Trees (Native and Naturalized), Agriculture 

Handbook No. 541 (1979), and are sometimes used as names for lumber. In addition to the official common names for a 

species, the Handbook lists other names by which the species and the lumber produced from it are sometimes designated.

12Cypress includes types designated as Red Cypress, White Cypress, and Yellow Cypress. Red Cypress is frequently classified 

and sold separately from the other types.

13 Balsam fir lumber is sometimes designated either as Eastern fir or as Balsam.

14 Douglas fir from Arizona, Colorado, Nevada, New Mexico and Utah is recognized as Douglas fir-South. 
24

Commercial Official Common

Species or Species Group Names8 Tree Names9 Botanical Names

FIR (continued)

Bigcone Douglas fir Bigcone Douglas fir P. macrocarpa

Noble Fir noble fir Abies procera

Alpine Fir subalpine fir (alpine fir) A. lasiocarpa

California Red Fir California red fir A. magnifica

Grand Fir grand fir A. grandis

Pacific Grand Fir Pacific silver fir A. amabilis

White Fir white fir A. concolor

HEMLOCK:

Carolina Hemlock Carolina hemlock Tsuga caroliniana

Eastern Hemlock eastern hemlock T. canadensis

Mountain Hemlock mountain hemlock T. mertensiana

Western Hemlock western hemlock T. heterophylla

JUNIPER:

Western Juniper alligator juniper Juniperus deppeana

Rocky Mountain juniper J. scopulorum

Utah juniper J. osteosperma

western juniper J. occidentalis

LARCH:

Western Larch western larch Larix occidentalis

PINE:

Bishop Pine Bishop pine Pinus muricata

Digger Pine Digger pine P. sabiniana

Knobcone Pine knobcone pine P. attenuata

Coulter Pine Coulter pine P. coulteri

Jeffrey Pine Jeffrey pine P. jeffreyi

Jack Pine jack pine P. banksiana

Limber Pine limber pine P. flexilis

Lodgepole Pine lodgepole pine P. contorta

Norway Pine red pine P. resinosa

Pitch Pine pitch pine P. rigida

Ponderosa Pine ponderosa pine P. ponderosa

Radiata/Monterey Pine Monterey pine P. radiata

Sugar Pine sugar pine P. lambertiana

Whitebark Pine whitebark pine P. albicaulis

Idaho White Pine western white pine P. monticola

Northern White Pine eastern white pine P. strobus
25

Commercial Official Common

Species or Species Group Names8 Tree Names9 Botanical Names

PINE (continued)

Longleaf Pine15

slash pine P. elliottii

longleaf pine P. palustris

Southern Pine (Major) loblolly pine P. taeda

longleaf pine P. palustris

shortleaf pine P. echinata

slash pine P. elliottii

Southern Pine (Minor) pond pine P. serotina

Virginia pine P. virginiana

sand pine P. clausa

spruce pine P. glabra

REDWOOD:

Redwood redwood Sequoia sempervirens

SPRUCE:

black spruce black spruce Picea mariana

red spruce red spruce P. rubens

white spruce white spruce P. glauca

Blue Spruce blue spruce P. pungens

Engelmann Spruce Engelmann spruce P. engelmannii

Sitka Spruce Sitka spruce P. sitchensis

Norway Spruce Norway spruce P. abies

TAMARACK:

Tamarack tamarack Larix laricina

YEW:

Pacific Yew Pacific yew Taxus brevifolia

 15 The commercial requirements for Longleaf Pine lumber are that not only must it be produced from trees of the botanical 

species of Pinus elliottii and Pinus palustris, but each piece in addition must average either on one end or the other not less 

than six annual rings per inch and not less than one-third summerwood. Longleaf Pine lumber is sometimes designated as 

Pitch Pine in the export trade.
26

APPENDIX B DEFINITIONS OF TERMS USED IN DESCRIBING

STANDARD GRADES OF LUMBER

B1. IEEE/ASTM SI 10-2002 was used as the 

authoritative 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 significant for dimensions greater 

than 1/8 inch, and the nearest 0.1 mm is 

significant for dimensions equal to or less than 

1/8 inch.

The rounding rule for dimensions greater than 

1/8 inch: if the digit in the tenths of mm position 

(the digit after the decimal point) is less than 5, 

drop all fractional mm digits; if greater than 5 or 

it is 5 followed by at least one non-zero digit, 

round one mm higher; if 5 followed by only 

zeroes, retain the digit in the unit position (the 

digit before the decimal point) if it is even or 

increase 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 

decimal point) is less than 5, drop all digits to 

the right of the tenths position; if greater than 5 

or it is 5 followed by at least one non-zero digit, 

round one-tenth mm higher; if 5 followed by only 

zeros, retain the digit in the tenths position if it 

is even or increase it one-tenth mm if it is odd.

CAUTION: Use great care when converting 

board feet, based on NOMINAL cross-sectional 

dimensions, to cubic meters of lumber, based on 

DRESSED cross-sectional dimensions. This is 

explained on page 32 of the IEEE/ASTM SI 10-

2002 by the following note: “(9) No conversion is 

given for “board foot” because “board foot” is not 

a well-defined unit of volume. Calculation of the 

number of board feet in a piece of lumber is 

based on the nominal dimensions of the cross 

section.”

Unfortunately, many older handbooks and 

dictionaries and some current references still 

contain erroneous or vague information about 

volume conversions to SI metric. The amount of 

dressing can also affect the cross-sectional 

dimensions. Therefore, use extra care when 

making conversions from NOMINAL board foot 

to actual cubic meters.

In case of a dispute on size measurements, the 

conventional (inch) method of measurement 

shall take precedence.

B2. Definitions of terms used in 

describing standard grades of lumber:

air dried-seasoned by exposure to the 

atmosphere, in the open or under cover, 

without artificial heat.

all-heart-of heartwood throughout; that is, free 

of sapwood.

annual ring-denotes the amount of growth for 

a tree in a single year.

bark pocket-patch of bark partially or wholly 

enclosed in the wood. Classified by size the 

same as pitch 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 edge to facilitate 

alignment of pieces.

blemish-anything marring the appearance of 

lumber.
27

bow-see WARP.

boxed heart-with the pith enclosed in the piece.

bright-unstained.

burl-a distortion of grain, usually caused by 

abnormal growth due to injury of the tree. 

The effect of burls is assessed in relation to 

knots.

ceiling-a piece of patterned, tongue and grooved 

lumber, used to cover the ceiling of a room, 

porch or other partially enclosed areas.

check-a separation of the wood normally 

occurring across or through the annual rings 

and usually as a result of seasoning.

roller check-a crack in the wood 

structure caused by a piece of cupped 

lumber being flattened in passing 

between the machine rollers.

surface check-a separation that occurs 

on a face of a piece.

small check-not over 0.8 mm (1/32 inch) 

wide or 102 mm (4 inch) long.

medium check-not over 0.8 mm (1/32 

inch) wide or 254 mm (10 inch) long.

large check-over 0.8 mm (1/32 inch) 

wide or longer than 254 mm (10 inch) 

or both.

through check-a separation that 

extends from one surface of a piece to 

the opposite or adjoining surface.

chipped grain-a barely perceptible irregularity 

in the surface of a piece caused when 

particles of wood are chipped or broken below 

the line of cut. It is too small to be classed as 

torn grain and is not considered unless in 

excess of 25 percent of the surface involved.

chip marks-shallow depressions or 

indentations on or in the surface of dressed 

lumber caused by shavings or chips getting 

embedded in the surface during dressing.

very light chip marks-not over 0.4 mm 

(1/64 inch) deep.

light chip marks-not over 0.8 mm (1/32 

inch) deep.

medium chip marks-not over 1.6 mm 

(1/16 inch) deep.

heavy chip marks-not over 3.2 mm (1/8 

inch) deep.

clear-free or practically free of all blemishes, 

characteristics, or defects.

compression wood-abnormal wood that forms 

on the underside of leaning and crooked 

coniferous trees. It is characterized, aside 

from its distinguishing color, by being hard 

and brittle and by its relatively lifeless 

appearance. Compression wood shall be 

limited in effect to other appearance or 

strength reducing characteristics permitted 

in the grade.

corner-the intersection of two adjacent faces.

crook-see definition for warp.

cross break-separation of the wood across the 

width.

crosscutting-cutting with a saw across the 

width.

cup-see definition for warp.

cutting-resulting pieces after crosscutting 

and/or ripping.

decay (unsound wood)-a disintegration of the 

wood substance due to action of wooddestroying fungi, and is also known as dote 

or rot.

advanced decay-an older stage of decay 

in which disintegration is recognized 

because the wood has become punky, 

soft, spongy, stringy, shaky, pitted, or 

crumbly. Decided discoloration or 

bleaching of the rotted wood is often 

apparent.

heart center decay-a localized decay 

developing along the pith in some 
28

species and is detected by visual 

inspection. Heart center decay 

develops in the living tree and does 

not progress further after the tree is 

cut.

honeycomb-similar to white specks but 

the pockets are larger. Where 

permitted in the grading rules, it is so 

limited that it has no more effect on 

the intended use of the piece than 

other characteristics permitted in the 

same grade. Pieces containing 

honeycomb are no more subject to 

decay than pieces which do not 

contain it.

incipient decay-an early stage of decay 

in which disintegration of the wood 

fibers has not proceeded far enough to 

soften or otherwise change the 

hardness of the wood perceptibly. It is 

usually accompanied by a slight 

discoloration or bleaching of the wood.

peck-channeled or pitted areas or 

pockets found in cedar and cypress. 

Wood tissue between pecky areas 

remains unaffected in appearance 

and strength. All further growth of 

the fungus causing peckiness ceases 

after the trees are felled.

pecky-characterized by PECK

pocket rot-decay which appears in the 

form of a hole, pocket, or area of soft 

rot, usually surrounded by apparently 

sound wood.

water soak or stain-water-soaked area 

in heartwood, usually interpreted as 

the incipient stage of certain wood 

rots.

white specks-small white or brown pits 

or spots in wood caused by the fungus 

Fomes pini. It develops in the living 

tree and does not develop further in 

wood in service. Where permitted in 

grading rules, it is so limited that it 

has no more effect on the intended 

use of the pieces than other 

characteristics permitted in the same 

grade. Pieces containing white speck 

are no more subject to decay than 

pieces which do not contain it.

degrades-pieces which on reinspection prove of 

lower quality than the grade in which they 

were shipped.

diagonal grain-a deviation in the slope of 

grain caused by sawing at an angle with the 

bark of the tree. See SLOPE OF GRAIN.

dry- lumber of less than nominal 5-inch 

thickness which has been seasoned or dried 

to a maximum moisture content of 19 

percent. Lumber of nominal 5-inch or greater 

in thickness (timbers) is often manufactured 

and sold without drying. When the 

maximum moisture content is specified for 

lumber of nominal 5-inch or greater 

thickness, it shall be in accordance with the 

provisions of the applicable lumber grading 

rules certified by the Board, which for some 

species defines dry lumber as having a 

maximum moisture content higher than 19 

percent [see 2.7].

eased edge-slightly rounded surfacing on pieces 

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 rectangularshaped pieces, or 2) the corner of a piece at 

the intersection of two longitudinal faces, or 

3) in stress grades, that part of the wide face 

nearest the corner of the piece.

edge grain (EG) [vertical grain (VG)] [rift 

grain]-a piece or pieces sawn at 

approximately 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 which wood neither gains nor 
29

loses moisture when surrounded by air at a 

given relative humidity and temperature.

finish-a high-quality piece of lumber graded for 

appearance, often used for interior trim or 

cabinet work.

firm red heart-a stage of incipient decay 

characterized by a reddish color in the 

heartwood which does not render the wood 

unfit for the majority of yard purposes.

flat grain (FG) [slash grain (SG)]-a piece or 

pieces sawn approximately parallel to the 

annual growth rings so that all or some of 

the rings form an angle of less than 45 

degrees with the surface of the piece.

flooring-a tongue and grooved piece of lumber 

typically used as a finished floor.

f.o.h.c. (free of heart centers)-without pith 

(side cut). An occasional piece, when showing 

pith for not more than 1/4 the length on the 

surface, shall be accepted.

free of wane-without wane but with either 

eased or square edges. (see WANE)

grain-the fibers in wood and their direction, 

size, arrangement, appearance, or quality.

green-lumber of less than nominal 5-inch 

thickness, which has a moisture content in 

excess of 19 percent. For lumber of nominal 

5-inch or greater thickness (timbers), green 

shall be defined in accordance with the 

provisions of the applicable lumber grading 

rules certified by the Board [See 2.11].

gum pocket-an opening between growth rings 

which contains or has contained resin, or 

bark, or both.

gum seam-check or shake filled with gum.

gum spot-an accumulation of gumlike 

substance occurring as a small patch. Often 

occurs in conjunction with a bird-peck or 

other injury to the growing wood.

gum streak-a well-defined accumulation of gum 

in more or less regular streak. Classified 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.

heartwood-the inner core of the tree trunk 

comprising the annual rings containing nonliving elements. In some species, heartwood 

has a prominent color different from 

sapwood. Heartwood and sapwood of 

equivalent character are compared as 

follows:

with regard to strength, heartwood 

and sapwood are equal. No 

requirement of heartwood is made 

when strength alone is the governing 

factor.

with regard to durability, heartwood 

is more durable than sapwood. When 

wood is to be exposed to decayproducing conditions without 

preservative 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 preservatives, sapwood 

takes preservative treatment more 

readily than heartwood.

hit-and-miss-a series of skips not over 1.6 mm 

(1/16 inch) deep with surfaced areas 

between.

hit-or-miss-lumber that is completely or partly 

surfaced or entirely rough with a maximum 

scantness of 1.6 mm (1/16 inch).

holes-openings that either extend partially or 

wholly through a piece. An alternate 

designation for holes which extend only 
30

partially through a piece is surface pits. 

Holes are classified by size as follows: 

pin hole-not over 1.6 mm (1/16 inch) in 

diameter.

medium hole-(small hole) not over 6 mm 

(1/4 inch) in diameter.

large hole-not over 25 mm (1 inch) in 

diameter.

very large hole-over 25 mm (1 inch) in 

diameter.

kiln-dried-seasoned in a chamber by means of 

artificial heat.

knife marks-the imprints or markings of the 

machine knives on the surface of dressed 

lumber.

very slight knife marks-marks that are 

visible only from a favorable angle 

and are perfectly smooth to the touch.

slight knife marks-marks that are 

readily visible but evidence no 

unevenness to the touch.

knot-a portion of a branch or limb that has 

become incorporated in a piece of lumber. In 

lumber, knots are classified as to form, size, 

quality, and occurrence.

knot formoval knot-produced when the limb is cut 

at slightly more than a right angle to 

the long axis.

round knot-produced when the limb is 

cut at approximately right angles to 

its long axis.

spike knot-produced when the limb is 

cut either lengthwise or diagonally.

knot sizepin knot-not over 13 mm (1/2 inch) in 

diameter.

small knot-not over 19 mm (3/4 inch) in 

diameter.

medium knot-not over 38 mm (1-1/2 

inch) in diameter.

large knot-over 38 mm (1-1/2 inch) in 

diameter.

knot qualityblack knot-results from a dead branch 

which the wood growth of the tree has 

surrounded.

decayed knot-softer than the 

surrounding wood, and containing 

advanced decay.

encased knot-not intergrown with the 

annual rings of the surrounding

wood.

firm knot-solid across its face but 

contains incipient decay.

fixed knot-retains its place in dry 

lumber under ordinary conditions but 

is movable under pressure though not 

easily pushed out.

hollow knot-a sound knot containing a 

hole greater than 6 mm (1/4 inch) in 

diameter. The through opening of a 

hollow knot is limited to the size of 

other holes permitted.

intergrown knot-a knot whose annual 

rings are partially or completely 

intergrown 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 

intergrown with the surrounding 

wood.

sound knot-contains no decay. 

star-checked knot-has radial checks.

tight knot-so fixed by growth, shape, or 

position that it retains its place in the 

piece.

unsound knot-contains decay.

water-tight knot-has annual rings 

completely intergrown with those of 

the surrounding wood on one surface 

of the piece, and it is sound on that 

surface.
31

knot occurrencebranch knots-two or more divergent 

knots sawed lengthwise and tapering 

toward the pith at a common point.

corner knot-located at the intersection 

of adjacent faces.

knot cluster-two or more knots grouped 

together as a unit with the fibers of 

the wood deflected around the entire 

unit. A group of single knots is not a 

knot cluster.

single knot-occurs by itself. The fibers of 

the wood being deflected around it.

loosened grain-a grain separation or loosening 

between springwood and summerwood 

without displacement.

very light loosened grain-not over 0.4 

mm (1/64 inch) separation.

light loosened grain-not over 0.8 mm 

(1/32 inch) separation.

medium loosened grain-not over 1.6 

mm (1/16 inch) separation.

heavy loosened grain-not over 3.2 mm 

(1/8 inch) separation.

very heavy loosened grain-over 3.2 mm 

(1/8 inch) separation.

lumber-Lumber is defined as a manufactured 

product derived from a log through sawing or 

planing. 

machine bite-a depressed cut of the machine 

knives at the end of a piece.

very light machine bite-not over 0.4 

mm (1/64 inch) deep.

light machine bite-not over 0.8 mm 

(1/32 inch) deep.

medium machine bite-not over 1.6 mm 

(1/16 inch) deep.

heavy machine bite-not over 3.2 mm 

(1/8 inch) deep.

very heavy machine bite-over 3.2 mm 

(1/8 inch) deep.

machine burn-a darkening of the wood due to 

overheating by machine knives or rolls when 

pieces are stopped in the machine.

machine gouge-a groove cut by the machine 

below the desired line.

very light machine gouge-not over 0.4 

mm (1/64 inch) deep.

light machine gouge-not over 0.8 mm 

(1/32 inch) deep.

medium machine gouge-not over 1.6 

mm (1/16 inch) deep.

heavy machine gouge-not over 3.2 mm 

(1/8 inch) deep.

very heavy machine gouge-over 3.2 

mm (1/8 inch) deep.

machine offset-an abrupt dressing variation in 

the edge surface which usually occurs near 

the end of the piece without reducing the 

width or without changing the plane of the 

wide surface.

very light machine offset-a variation 

not over 0.4 mm (1/64 inch).

light machine offset-a variation not 

over 0.8 mm (1/32 inch).

medium machine offset-a variation not 

over 1.6 mm (1/16 inch).

heavy machine offset-a variation not 

over 3.2 mm (1/8 inch).

very heavy machine offset-a variation 

over 3.2 mm (1/8 inch).

metric units-See B1.

mismanufacture-includes all defects or 

blemishes, produced in manufacturing. See 

CHIPPED GRAIN, HIT-AND-MISS, HITOR-MISS, LOOSENED GRAIN, MACHINE 

BURN, MACHINE GOUGE, MISMATCHED 

LUMBER, RAISED GRAIN, SKIP, TORN 

GRAIN, and VARIATION IN SAWING.

mismatch-an uneven fit in worked lumber 

when adjoining pieces do not meet tightly at 

all points of contact or when the surfaces of 

adjoining pieces are not in the same plane.
32

slight mismatch-a barely evident trace 

of mismatch.

very light mismatch-not over 0.4 mm 

(1/64 inch).

light mismatch-not over 0.8 mm (1/32 

inch).

medium mismatch-not over 1.6 mm 

(1/16 inch).

heavy mismatch-not over 3.2 mm (1/8 

inch).

mixed grain (MG)-either vertical or flat 

grained pieces or both.

moisture content-the weight of the water in a 

piece of lumber expressed in a percentage of 

the weight of the piece after being over dried. 

occasional pieces-not more than 10% of the 

pieces in a parcel or shipment.

partition—a tongue and grooved piece of 

lumber with the same pattern run on both 

sides. For use where both sides may be 

exposed.

pitch-an accumulation of resinous material.

light pitch-the light but evident 

presence of pitch.

medium pitch-a somewhat more evident 

presence of pitch than in the light 

pitch.

heavy pitch-a very evident accumulation 

of pitch showing by its color and 

consistency.

massed pitch-a clearly defined 

accumulation of solid pitch in a body 

by itself.

pitch seam-a shake or check which contains 

pitch.

pitch streak-a well-defined accumulation of 

pitch in the wood cells in a streak. Pitch 

streaks, with equivalent areas being 

permissible, are described as follows:

very small pitch streak-10mm (3/8 

inch) in width and 381 mm (15 inch) 

in length.

small pitch streak-1/12 the width and 

1/6 the length of the piece.

medium pitch streak-1/6 the width and 

1/3 the length of the piece.

large pitch streak-not over 1/4 the 

width by 1/2 the length of the surface.

very large pitch streak-over 1/4 the 

width by 1/2 the length of the surface.

pith-the small soft core in the structural center 

of a log.

very small pith-not over 3.2 mm (1/8 

inch) wide and occupies on the face 

surface not over 161 square mm (1/4 

square inch) [3.2 mm by 51 mm (1/8 

inch wide by 2 inch long), or 1.6 mm 

by 102 mm (1/16 inch by 4 inch)]

small pith-not over 484 square mm (3/4 

square inch) on the face surface [6 

mm by 76 mm (1/4 inch by 3 inch), 5 

mm by 102 mm (3/16 inch by 4 inch), 

3.2 mm by 152 mm (1/8 inch by 6 

inch), or 1.6 mm by 305 mm (1/16 

inch by 12 inch)]

free of pith-the prohibition of pith on or 

within the body of the piece.

boxed pith-pith that is within the four 

faces of an end of a piece.

pocket-a well-defined opening, between the 

rings of annual growth, which develops 

during the growth of the tree. It usually 

contains pitch or bark. Pockets are described 

as follows with equivalent areas being 

permissible:

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 inch) in length, or 6 mm (1/4 

inch) in width and 51 mm (2 inch) in 

length.
33

medium pocket-1.6 mm (1/16 inch) in 

width and 305 mm (12 inch) in 

length, or 3.2 mm (1/8 inch) in width 

and 203 mm (8 inch) in length, or 10 

mm (3/8 inch) in width and 102 mm 

(4 inch) in length.

large pocket-not over 2581 square mm 

(4 square inches) in area.

very large pocket-over 2581 square mm 

(4 square inches) in area.

closed pocket-an opening on one surface 

only.

open (through) pocket-an opening on 

opposite surfaces. A through opening 

is considered the same as a through 

hole of equal size.

raised grain-a roughened condition of the 

surface of dressed lumber in which the hard 

summerwood is raised above the softer 

springwood, but not torn loose from it.

very light raised grain-not over 0.4 

mm (1/64 inch). 

light raised grain-not over 0.8 mm 

(1/32 inch).

medium raised grain-not over 1.6 mm 

(1/16 inch).

heavy raised grain-not over 3.2 mm 

(1/8 inch).

resawn lumber-the product of sawing any 

thickness of lumber to develop thinner 

lumber.

ripped lumber-the product of sawing any width 

of lumber to develop narrower lumber.

sapwood-the outer layers of growth between the 

bark and heartwood that contain the sap.

bright sapwood-sapwood that shows no 

stain and is not limited in any grade 

unless specifically stated in the grade 

description.

sapwood restrictions waived-a lifting 

of any restrictions in a rule on the 

amount of sapwood permitted in 

pieces graded under that rule.

bright sapwood no defect (BSND)-an 

indication that bright sapwood is 

permitted in each piece in any 

amount.

seasoning-evaporation or extraction of moisture 

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 opening.

light shake-not over 0.8 mm (1/32 inch) 

wide.

medium 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 

surface of a piece.

through shake-extends from one surface 

of a piece to the opposite or to an 

adjoining surface.

pith shake (heart check or heart 

shake)-extends through the annual 

rings from or through the pith 

towards the surface of a piece, and is 

distinguished from a seasoning check 

by the fact that its greatest width is 

nearest the pith, whereas the greatest 

width of a season check in a pithcentered piece is farthest from the 

pith.

side cut-pith is not enclosed within the four 

sides of the piece.

skip-area on a piece that failed to surface clean. 

Skips are described as follows:

very light skip-not over 0.4 mm (1/64 

inch) deep.

light skip-not over 0.8 mm (1/32 inch) 

deep.

medium skip-not over 1.6 mm (1/16 

inch) deep.
34

heavy skip-not over 3.2 mm (1/8 inch) 

deep.

slope of grain-the deviation of the line of fibers 

from a straight line parallel to the sides of 

the piece.

softwood-one of the group of trees which have 

needle-like or scale-like leaves. The term has 

no specific reference to the softness of the 

wood.

sound-free of decay.

spiral grain-a deviation in the slope of grain 

caused when the fibers in a tree take a spiral 

course around the trunk of the tree instead of 

the normal vertical course.

split-a separation of the wood through the piece 

to the opposite surface or to an adjoining 

surface due to the tearing apart of the wood 

cells.

very short split-equal in length to 1/2 

the width of the piece.

short split-equal in length to the width 

of the piece and in no case exceeds 1/6 

the length.

medium split-equal in length to twice 

the width of the piece and in no case 

exceeds 1/6 the length.

long split-longer than a medium split.

springwood-the portion of the annual ring 

formed during the early part of the yearly 

growth period. It is lighter in color, less 

dense, and not as strong mechanically as 

summerwood.

square corners-without eased edges but has an 

allowance for wane in certain grades.

square edged-free from wane and without 

eased edges.

stained wood-a discoloration in wood.

stained heartwood or firm red heartheartwood that shows a marked 

variation 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 

ranges from pink to brown, and is not 

to be confused with natural red heart. 

Natural color is usually uniformly 

distributed through certain annual 

rings, whereas stains are usually in 

irregular patches.

stained sapwood-sapwood with 

discoloration. In grades when it is 

permitted, stained sapwood has no 

more effect on the intended use of a 

piece than other characteristics 

permitted in the grade but it does 

affect appearance in varying degrees:

light stained sapwood-a 

discoloration so slight that it 

does not affect natural 

finishes.

medium stained sapwood-a 

pronounced difference in 

coloring. Note: Sometimes the 

usefulness for natural finishes 

but not for paint finishes is 

affected.

heavy stained sapwood-a so 

pronounced difference in color 

that the grain of the wood is 

obscured, but lumber 

containing it is acceptable for 

paint finishes.

stained wood resulting from exposure 

to the elements-discolored wood that 

is permitted in all grades of framing 

and sheathing lumber.

stepping-lumber designed to be used for stair 

treads. Customarily surfaced three sides and 

bull-nosed on one edge.

stress grades-lumber having assigned working 

stresses and modulus of elasticity values in 

accordance with accepted basic principles of 
35

strength grading, and the provisions of 

6.3.2.1 and 6.3.2.2 of this Standard.

summerwood-the portion of the annual ring 

formed during the latter part of the yearly 

growth. It is darker in color, more dense, and 

stronger mechanically than springwood.

torn grain-an irregularity in the surface of a 

piece where wood has been torn or broken 

out by surfacing.

very light torn grain-not over 0.4 mm 

(1/64 inch) deep.

light torn grain-not over 0.8 mm (1/32 

inch) deep.

medium torn grain-not over 1.6 mm 

(1/16 inch) deep.

heavy torn grain-not over 3.2 mm (1/8 

inch) deep.

very heavy torn grain-over 3.2 mm (1/8 

inch) deep.

trim-to cross-cut a piece to a given length.

double-end trimmed (DET)-lumber 

trimmed square on both ends. 

Tolerances are found in certified 

grading rules. 

precision-end trimmed (PET)-lumber 

trimmed square on both ends to 

uniform lengths with a 

manufacturing tolerance of 1.6 mm 

(1/16 inch) over or under in length in 

20% of the pieces.

square-end trimmed-lumber trimmed 

square and having a manufacturing 

tolerance of 0.4 mm (1/64 inch) for 

each nominal 2 inch of thickness or 

width.

unsound - see definition for decay.

variation in sawing-a deviation from the line 

of cut. 

slight variation-not over 1.6 mm (1/16 

inch) scant in nominal 1-inch lumber, 

3.2 mm (1/8 inch) in nominal 2-inch, 5 

mm (3/16 inch) in nominal 3-inch to 7-

inch, and 6 mm (1/4 inch) in nominal 

8-inch and greater thickness or width.

wane-bark or lack of wood from any cause, 

except eased edges, on the edge or corner of a 

piece of lumber.

warp-any deviation from a true or plane 

surface, including bow, crook, cup, twist, or 

any combination thereof. Warp restrictions 

are based on the average form of warp as it 

occurs normally, and any variation from this 

average form, such as short kinks, shall be 

appraised according to its equivalent effect. 

Pieces containing two or more forms of warp 

shall be appraised according to the combined 

effect in determining the amount 

permissible. In grading rules, warp is 

classified as very light, light, medium, and 

heavy, and applied to each width and length 

as set forth in the various grades in 

accordance with the following provisions:

bow-a deviation flatwise from a straight 

line drawn from end to end of a piece. 

It is measured at the point of greatest 

distance from the straight line. 

crook-a deviation edgewise from a 

straight line drawn from end to end of 

a piece. It is measured at the point of 

greatest distance from the straight 

line.

cup-a deviation in the face of a piece 

from a straight line drawn from edge 

to edge of a piece. It is measured at 

the point of greatest distance from the 

straight line.

twist-a deviation flatwise, or a 

combination of flatwise and edgewise, 

in the form of a curl or spiral, and the 

amount is the distance an edge of a 

piece at one end is raised above a flat 

surface against which both edges at 

the opposite end are resting snugly.

wavy dressing-an involvement of more uneven 

dressing than knife marks.

very light wavy dressing-not over 0.4 

mm (1/64 inch) deep.
36

light wavy dressing-not over 0.8 mm 

(1/32 inch) deep.

medium wavy dressing-not over 1.6 

mm (1/16 inch) deep.

heavy wavy dressing-not over 3.2 mm 

(1/8 inch) deep.

very heavy wavy dressing-over 3.2 mm 

(1/8 inch) deep. 
37

APPENDIX C LUMBER INDUSTRY ABBREVIATIONS

These abbreviations are commonly used for softwood lumber, although all of them are not 

necessarily applicable to all species. Additional abbreviations which are applicable to a particular region 

or species shall not be used unless included in certified grading rules.

Abbreviations are commonly used in the forms indicated, but variations such as the use of upperand lower-case type, and the use or omission of periods and other forms of punctuation are not required. 

AD Air-dried

ADF After deducting freight sides

ALS American Softwood Lumber Standard

AV or AVG Average

Bd Board

Bd ft Board foot or feet

Bdl Bundle

Bev Beveled

B/L Bill of lading

BM Board Measure

Btr Better

B&B or B&Btr B and better

B&S Beams and stringers

CB1S Center bead one side

CB2S Center bead two sides

CF Cost and freight

CG2E Center groove two edges

CIF Cost, insurance, and freight

CIFE Cost, insurance, freight, and exchange

Clg Ceiling

Clr Clear

CM Center matched

Com Common

CS Caulking seam

Csg Casing

Cu Ft Cubic foot or feet

CV1S Center Vee one side

CV2S Center Vee two sides

D&H Dressed and headed

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
38

E&CB2S Edge and center bead two sides

E&CV1S Edge and center Vee one side

E&CV2S Edge and center Vee two sides

EE Eased edges

EG Edge (vertical) grain

EM End matched

EV1S Edge Vee one side

EV2S Edge Vee two sides

Fac Factory

FAS Free alongside (named vessel)

FBM Foot or board measure

FG Flat (slash) grain

Flg Flooring

FOB Free on board (named point)

FOHC Free of heart center or centers

FOK Free of knots

Frt Freight

Ft Foot or feet

GM Grade marked

G/R or G/Rfg Grooved roofing

HB Hollow back

H&M hit-and-miss

H or M hit-or-miss

Hrt Heart

Hrt CC Heart cubical content

Hrt FA Heart facial area

Hrt G Heart girth

IN Inch or inches

J&P Joists and planks

KD Kiln-dried

Lbr Lumber

LCL Less than carload

LFT or Lin Ft Linear foot or feet

Lgr Longer

Lgth Length

Lin Linear

Lng Lining M Thousand

MBM Thousand (feet) board measure

MC Moisture content

Merch Merchantable

Mldg Moulding

mm Millimeter

No Number

N1E Nosed one edge

N2E Nosed two edges

Og Ogee

Ord Order

Par Paragraph
39

Part Partition

Pat Pattern

Pc Piece

Pcs Pieces

PE Plain end

PO Purchase order

P&T Post and timbers

Reg Regular

Res Resawed or resawn

Rfg Roofing

Rgh Rough

R/L Random lengths

R/W Random widths

R/W&L Random widths and lengths

Sdg Siding

Sel Select

S&E Side and Edge (surfaced on)

SE Sdg Square edge siding

SE & S Square edge and sound

S/L or S/LAP Shiplap

SL&C Shipper's load and count

SM or Std M Standard matched

Specs Specifications

Std Standard

Stpg Stepping

Str or Struc Structural

S1E Surfaced one edge

S1S Surfaced one side

S1S1E Surfaced one side and one edge

S1S2E Surfaced one side and two edges

S2E Surfaced two edges

S2S Surfaced two sides

S2S1E Surfaced two sides and one edge

S2S&CM Surfaced two sides and center matched

S2S&SM Surfaced two sides and standard matched

S4S Surfaced four sides

S4S&CS Surfaced four sides and caulking seam

T&G Tongued and grooved

VG Vertical grain

Wdr Wider

Wt Weight
40

APPENDIX D IMPLEMENTATION AND MAINTENANCE OF STANDARD

D1. STANDING COMMITTEE

The American Lumber Standard Committee 

(ALSC) acts as the Standing Committee for this 

Standard for the purpose of its interpretation 

and for considering future proposals for 

amendments and revisions. Members of the 

ALSC and their alternates are appointed by the 

Secretary of Commerce in accordance with 

Section 9 of this Standard. The names of the 

members are available from the Committee's 

secretariat: Standards Services Division, 

National Institute of Standards and Technology, 

Gaithersburg, Maryland 20899-2150. Comments 

regarding the Standard and suggestions for its 

amendment or revision may also be sent to this 

address. No product shall be advertised or 

represented in any manner that would imply 

approval or endorsement of that product by the 

National Institute of Standards and Technology 

and/or the Department of Commerce.

D2. EFFECTIVE DATE

Voluntary Product Standard PS 20-10, American 

Softwood Lumber Standard, a voluntary 

standard developed under the Department of 

Commerce procedures, shall be effective June 1, 

2010 for products produced thereunder on and 

after that date. The Standard being superseded, 

American Softwood Lumber Standard PS 20-05, 

is effective for products produced thereunder 

through May 31, 2010.

D3. HISTORY OF THE STANDARD

Early in 1922 Secretary of Commerce Herbert 

Hoover, responding to a request from the lumber 

industry, offered the cooperation of the 

Department in activities directed toward 

simplification, standardization, and development 

of adequate quality guarantees for the lumberconsuming public. This cooperation led to the 

development and publication in 1924 of 

Simplified Practice Recommendation R 16 under 

the guidance of the Department's Division of 

Simplified Practices, which was to become a part 

of the National Bureau of Standards (now the 

National Institute of Standards and 

Technology). The history of R 16's development 

and its subsequent revisions is summarized in 

editions issued, respectively, in 1924, 1925, 

1926, 1929, 1939, and 1953.

R 16-53 was revised in 1969 and superseded by 

Voluntary Product Standard PS 20-70 American 

Softwood Lumber Standard. The significant 

provisions added to PS 20-70 were: 1) separate 

size standards for dry and green lumber, under 

nominal 5-inch thickness, were established in 

order to achieve greater uniformity in the 

dimensions of seasoned and unseasoned lumber 

at the point of use; 2) an independent National 

Grading Rule Committee was created to 

establish and maintain a national grading rule 

for dimension lumber conforming to PS 20; 3) an 

independent Board of Review was formed to 

assure uniform approval of grading rules and of 

agencies to grade under these rules, and to 

enhance enforcement of the accreditation 

program ; 4) the composition of the American 

Lumber Standard Committee was expanded to 

reflect a broader representation of interests; and 

5) uniform methods for assignment of design 

values were accepted. Non-substantive changes 

were made to the Standard in 1985, 1991, 1992 , 

1999 and 2005. The Standard was reviewed in 

2009 to assure it reflected the needs of 

manufacturers, distributors and consumers.

D4. CURRENT EDITION

The current edition, PS 20-10, has the same 

technical requirements and administrative 

structure for implementing and enforcing the 

Standard as its previous edition. This new 

edition was based on the recommendations 

resulting from an extensive technical and 

editorial review of PS 20-05 conducted by the 

Standing Committee with the assistance from 

the National Institute of Standards and 

Technology in 2009.