Standards are published documents that establish specifications and procedures designed to ensure the reliability of the materials, products, methods, and services people use every day. The Rules for the inspection of lumber are uniform in construction and application but also carry with them the element of stability. It is a process of growth and expansion to meet the necessities of varying conditions and markets and will continue as long as the trade endures.
Every four years, NHLA reviews the hardwood lumber grading rules and accepts rules change proposals for consideration. In the final step of the process, ballots containing new rules change proposals are sent to all Active Members. Each Active Member may vote for or against the proposed rules change provided such ballot is returned to and received by NHLA within 30 days from the date on the ballot. Rules change proposals that receive a favorable vote on a two-thirds majority of the votes properly cast by the Active Members will be adopted and become effective January 1 of the proceeding year.
For questions about the rules change process, please contact Chief Inspector Dana Spessert. Privacy Policy Use of Cookies. Sign up for our Newsletter. In the Common grades, a cutting shall be flat enough to surface two sides to standard surfaced thickness after it has been removed from the board. Diagonal cuttings are not permitted.
Clear-Face Cutting A cutting having one clear face ordinary season checks are admitted and the reverse side sound as defined in Sound Cutting. The clear face of the cutting shall be on the poor side of the board except when otherwise specified. Sound Cutting A cutting free from rot, pith, shake and wane. Texture is not considered. It will admit sound knots, bird pecks, stain, streaks or their equivalent, season checks not materially impairing the strength of a cutting, pin, shot and spot worm holes.
Check A length-wise separation of the wood that usually extends across the rings of annual growth and commonly results from stresses set up in wood during seasoning. Mineral Streak A n olive to greenish-black or brown discoloration of undetermined cause in hardwoods. Sound Knot A knot that is solid across its face, hard as the surrounding wood and shows no indication of decay. Quartered Lumber There are 12 cutting units in 1 square foot or 1 foot of surface measure.
Cutting units are calculated by multiplying the width of a cutting measured in inches and fractions of an inch by the length measured in feet and fractions of a foot. The number of units obtained in the cuttings of a board are totaled and used as one requirement in the individual grades. To determine the number of cutting units required by each grade, the surface measure is multiplied as follows:.
The result will be the required number of inches in length. The result is the average width in inches. Note: When lumber has been resawn and sold as such, the pieces obtained from the original board should be kept together, inspected on the outer surfaces and tallied as one piece. When the pieces are not kept together and it is not possible to inspect them as one piece, then each piece must be inspected and tallied individually.
Before applying such inspection at destination the buyer should inform the seller of the condition of the lumber and they should agree on the basis of the inspection.
Selects and No. FAS No piece shall be admitted which contains pith, boxed or showing, exceeding in the aggregate in inches in length the surface measure in feet. Wane shall not exceed on either edge of the piece over one-half the length in the aggregate.
Splits shall not exceed in the aggregate in inches in length twice the surface measure of the piece, except when one foot or shorter and covered by Paragraph Splits may diverge up to one inch to the lineal foot, except when one foot or shorter and covered by Paragraph The average diameter of any knot, or hole, shall not exceed in inches one-third the surface measure of the piece in feet, except when it lies entirely within the first lineal foot of a board and is covered by Paragraph Shall grade not below FAS on the better face for the particular species, and not below No.
The reverse side of the cuttings in both FAS and No. Wane on the No. Selects The grading requirements for FAS in Paragraphs 55 to 63 inclusive shall apply to the better face of the piece. No piece shall be admitted which contains pith, boxed or showing, exceeding in the aggregate one-half its length.
There is no restriction as to pith when outside of the required cutting area. Note: No. There is no limit to the number of cuttings. Below Grade Sound Wormy Sound Wormy shall grade not below No. Other sound defects which do not exceed in extent or damage the defects described are admitted in the cuttings.
Unless otherwise specified, Sound Wormy shall include the full product of the log in No. Wane in Selects Pcs. Length can be on both edges.
Add widest wane together. Add total length of wane from both edges. The reverse side of the cuttings shall be sound. Red Birch When Specified Each required cutting shall have one clear heartwood face. White Maple is divided into No. In No. See Page 12, Par. The board will be considered straight grained when the grain does not diverge more than 1 in. Swirly grain, cross grain, curly grain, birds-eye, mineral streaks and spots and season checks shall not be admitted on either face of the required cuttings.
Note: In Basswood, black or brown spots or streaks are admitted in the cuttings in No. Note: A National Hardwood Lumber Association inspector will use his best judgment in considering birdseye, streaks and spots, excessive curly and cross grain, but the Association will not assume liability for these features. Gum streaks and spots are admitted without limit. See Page 12, Paragraph Quartered Sycamore Quarter Sawn Sycamore shall be graded according to the rules for Quarter Sawn Oak except that mineral streaks and spots and streaks and spots of similar nature are admitted without limit.
It is not limited in the Common grades. See Page 11, Par. Note: Stain will be light gray when the piece is surfaced two sides to standard surfaced thickness. Any part of the sapwood allowed may be included in the cuttings. See Standard Defects on page The reverse side of the board shall be sound as defined in Sound Cutting or the reverse side of the board grading not below No.
The reverse side of the cuttings shall be sound as defined in Sound Cutting or the reverse side of the board grading not below No. Sapwood is admitted without limit on the reverse side. When located away from the edges and ends where they cannot be admitted as the equivalent to wane defects, the following shall be considered as standard defects:.
Three spot worm holes or their equivalent equals one defect. In the wane defect, wane may extend through the full thickness of the piece showing on both faces. Note: Sap Gum is lumber produced from the Sweet Gum tree containing sapwood in excess of the quantity admitted in the grades of Red Gum lumber. For the grading rules regarding the various Gum separations, see below. Ribbon Stripe: When ribbon stripe figure is specified each piece shall be selected for the stripe effect caused by the wavy grain brought out in quarter sawing.
Plain Red Gum Red Gum is lumber produced from the Sweet Gum tree, containing sufficient heartwood to be admitted into the grades defined under the caption of Red Gum. Stain is admitted in the sapwood in all grades. F1F: Standard. Unlimited sapwood is admitted on the reverse side. Pieces below the grade of No. Plain Sawn Red Gum, Figured Wood Each piece shall be especially selected for markings and color tones of spots and streaks producing a variegated effect on the surface.
Otherwise the rules for Plain Red Gum shall apply. Quartered Red Gum No figure is required. The reverse side of any piece will admit sapwood aggregating one-fifth of its surface. Ribbon Stripe: When ribbon stripe figure is specified each piece should be selected for the stripe effect caused by the wavy grain brought out in quarter sawing. Quartered Red Gum, Figured Wood Each piece shall be especially selected for markings and color tones of spots and streaks producing a variegated effect on the surface.
Otherwise the rules for Quartered Red Gum shall apply. Each required cutting will admit without limits sound knots, spot worm holes, pin worm holes, bird peck, streaks, stain, and burls. Knots admitted may contain checks or splits not exceeding in depth one-half the thickness of the piece.
When this method is agreed upon, the surface measure and grade shall be determined inside the markings on the piece. Rustic Oak The grading rules for Colonial Poplar shall apply in all respects, except that one additional cutting is allowed.
General Instructions and Standard Grades Pages shall govern the measurement and inspection of all commercial hardwoods indigenous to the Northwest hardwood belt, with the exceptions as set forth under the respective species. These rules shall apply to green, dry, rough or surfaced lumber. No exception shall be made to these rules unless agreed to by the seller and the buyer and specificallystated in the purchase order.
The reverse side of the cuttings in both the Superiors and Cabinet grade face is not required to be sound. On the reverse or Cabinet side, wane or its equivalent shall not exceed one fourth the width by three-fourths the length in the aggregate, or pieces may alternately have wane one- third the width by one-half the length in the aggregate.
Width of the wane may be divided and show on both edges. The grade shall be determined from the worst face of the board.
Wane shall not exceed one-fourth the width or one half the length of the piece. Width of wane may be divided and shown on both edges. Length of wane allowed both edges. Other defects are admitted if they do not impair the strength of the cuttings.
General Instructions and Standard Grades pages 4—19 shall govern the measurement and inspection of all commercial hardwoods indigenous to the Northwest hardwood belt, with the exceptions as set forth under the respective species.
Pith: No piece shall be admitted which contains pith exceeding in the aggregate in inches in length twice the surface measure in feet. Splits: No piece shall be admitted which contains splits exceeding in the aggregate in inches in length twice the surface measure of the piece in feet, nor when diverging more than one inch to the foot in length, except when one foot or shorter and covered by Paragraph 59 of Standard Grades. On the No. The reverse side of the cuttings in Selects and Better and No.
Note: Lumber poorer in cutting percentage, or less in width or length than admitted in No. Wane: Wane shall not exceed one-fourth the width and one-half the length of the piece. Sound knots that do not exceed in their greatest dimension one-half the width of the cutting and other defects that do not impair the strength of the cutting more than the above mentioned defects are admitted. Rules apply to both faces of the piece. These rules for Cypress are complete under this caption and are not to be confused with any standard grades or other species shown elsewhere in this book.
Requests to Association inspectors for inspection of Cypress at loading point should be accompanied by a copy of the order on which shipment is to be made. Lumber shall be inspected and measured as the inspector finds it, of full length and width.
He shall make no allowance for the purpose of raising the grade, except that imperfections in rough stock which can be removed in dressing to standard surfaced thickness shall not be considered in determining the grade; otherwise the defects admissible in rough and dressed stock shall be the same for like kinds and grades. These rules define the poorest piece in any given grade, but the respective grades shall contain all pieces up to the next higher grade.
The grade shall be determined from the better face of the board. In lumber of standard thickness less than 1 inch, the board-foot measurement shall be based on the surface dimensions. In lumber measured with a board rule a piece tally in feet shall be made and this tally shall be the number of feet board measure of 1-inch lumber. The tally of lumber thicker. In material measured with a board rule, random width pieces measuring to the even half foot shall be alternately counted as of the next higher and lower foot count; fractions below the half foot shall be dropped and fractions above the half foot shall be counted as of the next higher foot.
Lumber shipped on stock or specified widths shall be tallied by the number of pieces of each size and length. All grades shall be stock widths, unless otherwise specified.
Lumber having greater variation in thickness, except as to wane, between the thinnest and thickest points, than shown in the following table shall be measured for thickness at the thinnest point and classed as miscut, and shall be graded and reported as such.
Moisture Contents Warp and Cup When defects or blemishes, or combinations thereof, not described in these grading rules are encountered, they will be considered as equivalent to known defects according to their damaging effect upon the piece in the grade under consideration. Standard definitions of the defects and blemishes usual in Cypress are as follows: A defect is defined as any irregularity occurring in or on wood that may lower some of its strength, durability, or utility values.
A blemish is defined as anything not classified as a defect, marring the appearance of the wood. Checks A check is a lengthwise separation of the wood, which occurs usually across the rings of annual growth. A surface check is a check occurring on the surface of the piece. An end check is one occurring on an end of a piece. A through check is one extending from one surface through the piece to the opposite surface or to an adjoining surface.
A heart check is one starting at the pith and extending toward but not to the surface of the piece. Decay is a disintegration of the wood substance due to the action of the wood-destroying fungi.
Incipient decay is the early stage of decay in which the disintegration 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. Advanced or typical decay is the older stage of decay in which the disintegration is readily recognized because the wood has become punky, soft and spongy, stringy, ring shaked, pitted, or crumbly.
Decided discoloration or bleaching of the rotted wood is often apparent. A peck is typical decay which appears in the form of a hole, pocket, or area of soft rot usually surrounded by sound wood. Holes Holes in wood may extend partially or entirely through the piece and be from any cause. When holes are permitted the average of the maximum length and maximum width shall be used in measuring the size, unless otherwise stated.
Knots Knots are classified according to size, form, quality, and occurrence. The average of the maximum length and maximum width shall be used in measuring the size of knots, unless otherwise stated.
A round knot is one oval or circular in form. A spike knot is a branch or limb sawed in a lengthwise direction. A sound knot is solid across its face, as hard as the surrounding wood, and shows no indications of decay. It may vary in color from red to black. An unsound knot will not impair the strength of the board. A decayed knot is softer than the surrounding wood and contains advanced decay.
A tight knot is one so fixed by growth or position that it will firmly retain its place in the piece. An intergrown knot is one whose rings of annual growth are completely intergrown with those of the surrounding wood.
A water-tight knot is one whose rings of annual growth are completely intergrown with those of the surrounding wood on one surface of the piece, and which is sound on that surface. An encased knot is one whose rings of annual growth are not intergrown and homogenous with those of the surrounding wood. The encasement may be partial or complete. A loose knot is one not held firmly in place by growth or position and cannot be relied upon to remain in place in the board.
A hollow knot is an apparently sound knot with a relatively large hole in it. Manufacturing Defects Manufacturing defects include all defects or blemishes which are produced in manufacturing, such as chipped grain, loosened grain, raised grain, torn grain, machine burn, and machine gouge. Chipped grain means that a part of the surface is chipped or broken out in very short particles below the line of cut.
Loosened grain means that a small portion of the wood has become loosened but not displaced. Raised grain is a roughened condition of the surface of dressed lumber in which the hard summer wood is raised above the softer spring wood, but not torn loose from it. Torn grain means that a part of the wood is torn out in dressing, and in depth is four distinct characters; slight, medium, heavy and deep.
A skip is an area on a piece that failed to surface. A slight skip is one that failed to surface smoothly, whose area does not exceed the product of the width of the piece in inches multiplied by 6. A heavy skip is one that the planer knife did not touch. A machine burn is a darkening or charring of the wood due to overheating by the machine knives.
A machine gouge is a groove across a piece due to the machine cutting below the desired line of cut. Shake A shake is a lengthwise separation of the wood, which occurs usually between and parallel to the rings of annual growth. A fine shake is one with a barely perceptible opening. A through shake is one extending from one surface through the piece to the opposite surface or to an adjoining surface.
A round shake is one completely encircling the pith. A cup shake is one that does not completely encircle the pith. Splits A split is a lengthwise separation of the wood due to the tearing apart of the wood cells.
A short split is one not exceeding in length either the width of a piece or one-sixth its length. A medium split is one exceeding in length the width of a piece but does not exceed one-sixth its length. A long split is one exceeding in length one-sixth of the length of the piece. Stain or Discoloration Stain is a discoloration, occurring on or in lumber, of any color other than the natural color of the piece, on which it appears.
It is classified as light medium and heavy. Light stain is a slight difference in color which will not materially impair the appearance of the piece if given a natural finish. Medium stain is a pronounced difference in color which, although it does not obscure the grain of the wood, would customarily be objectionable in a natural but not in a painted finish. Heavy stain is a difference in color so pronounced as practically to obscure the grain of the wood.
Wane Wane is bark, or the lack of wood or bark, from any cause on the edge or corner of a piece. Standard Grades Graded from better face with reverse side not below No. Wane on No. The commons are a staple grade useful for all types of general construction, finish, trim, pattern stock, and other uses where ordinary tree characteristics either enhance the appearance of the piece or do not restrict the appropriate application of the piece.
Graded from standpoint of strength primarily used as poor face of a Select and Better board. Admits any number of the following or equivalent:.
Will admit split equal to the width of board in the aggregate. Admits any number of the following or equivalent: Checks not extending through the piece and not impairing the strength of the piece, stain, slight peck, and pin worm holes.
Grade same as No. Defect graded from standpoint of strength. No odd lengths admitted unless otherwise specified. Must be suitable for ordinary fencing or dimension purposes in its full width and length. Checks not extending through the piece shall be admitted without limit providing they do not impair the strength of the piece.
Pith is admitted. No open holes are permitted. Any unsound knot must not impair the strength of the piece. The peck must not allow light to show through the piece. Each piece must be suitable for ordinary handling and construction without breakage. Will admit firm pith heart center well boxed; season checks; stain; pin worm holes; sound knots; slight peck in ends; slight shake in ends not extending to the surface; slight shake and slight peck on the surface, the aggregate of each not exceeding one-fourth the length of the piece; wane not exceeding one-eighth the width of a face on one corner or its aggregate equivalent on two or more corners.
Will admit pith heart center boxed or showing on the surface; season checks; stain; pin worm holes; medium holes; sound, encased and pith knots; unsound knots not to exceed in diameter one-third the width of the face on which they appear; split not exceeding one-sixth the length of the piece; wane not exceeding one-half the width of the face on which it appears; peck and through shake that do not seriously impair the strength of the piece.
The number of allowed cuttings is the surface measure divided by 4. Grading is made on the poorest face of the board. Minimum size of cuttings: 2. For this grade, grading is made on the clearest face.
The number of allowed cuttings is 1 plus the surface measure, divided by 3. Grading is made on the poorest face. Minimum size of cuttings: 1. The number of allowed cuttings is the surface measure divided by 2. Grades for Small, Clear Mesquite Pieces Although small, clear mesquite lumber pieces are eminently useful for a variety of purposes, if their widths or lengths are too small, they cannot be classified according to rough lumber grades.
Accordingly, the following grades were adopted from the National Dimension Manufacturers Association for small furniture pieces: C1F CLEAR ONE FACE : This material shall be clear on one side or face, both edges and both ends, and shall otherwise comply with the clear two face quality, except that the reverse face may contain defects of sound quality.
CORE: This material shall be sound on both faces admitting tight sound knots, small worm holes, slight surface checks or their equivalent. Fractions of over one-half foot in length shall be counted up, and fractions of one-half foot or less in length shall be dropped, except in the grades of Shorts. This does not change the minimum length requirements of the respective grades.
Sapwood is not allowed in the cuttings on both faces in all grades. Strips Inspection shall be made from the better face of the piece. Odd lengths are admitted without limit. Fractions over one-half foot in length shall be counted up, and fractions of one-half foot or less in length shall be dropped. This does not change the minimum length requirement of Strips.
The widths in Clear and No. In Clear Strips, tapering pieces shall be measured at the narrow end. In the grade of No. Sapwood is admitted without limit in all grades. If the lumber is to be kiln dried at the request of the purchaser, the kiln drying charge shall be clearly shown and identified on the quotation and invoice. When inspecting kiln dried lumber National Inspectors will make no addition for estimated kiln shrinkage.
In contracts for kiln dried lumber, the Standard Kiln Dried Rule shall apply unless otherwise specified in the sales contract. Standard Kiln Dried Rule Kiln dried lumber will be graded and measured as such, the grading rules for air dried lumber to be applied in all respects, unless otherwise specified.
In other respects the rules for grading air dried lumber shall apply. Kiln Drying of Hardwood Lumber Note: In order to minimize dimensional changes in service, hardwood lumber used for most products must have moisture removed by placing it in a dry kiln with controlled humidity and heat for a period of time determined by the starting and the desired moisture content, the species, and the thickness.
Other advantages of kiln drying are the relieving of stresses and the killing of insects and organisms causing stain and decay. Moisture content of wood is ordinarily expressed as the percentage of the weight of water in the wood to the oven dry weight of the wood. Kiln drying is a specialized technical process. Custom kiln drying is a contractual agreement between the kiln operator and the owner of the lumber.
Some degrade also occurs in kiln drying. Government Printing Office, N. Capitol Street, Washington, D. Surfaced Lumber D1S Shall be inspected according to the rules governing lumber dressed two sides, except that inspection shall be made from the dressed face. Shall be inspected according to the rules for rough lumber. Stock shall be straight, flat and square edged. Sapwood is not admitted in Red Gum, Cherry, Mahogany and unsteamed Walnut unless otherwise specified.
Stain is admitted in all grades in woods in which it is admitted in the Standard grade of FAS. When kiln dried, the additional tolerances in size allowed for kiln dried lumber apply.
See page 56, Inspection Kiln Dried Lumber. All pieces shall be free of end checks in the full length specified.
Pieces may be in multiple lengths. General instructions as to miscut lumber shall apply. Note: Six percent of the shipment may consist of pieces having defects on the edge or end, or both, which shall be measured off to make the grade or a smaller size ordered.
SELECTS: Clear three corners and two adjacent faces, the remaining corner and two faces to be clear one-half length; the other half will admit sound defects and wane not exceeding one-fourth the thickness of the piece.
Plain Sawn Flitch Shall be graded according to the general rules applying to lumber of the same species except that the grade requirements shall be based on the surface measure of the narrow face. There is no restriction as to pith in the cutting grades, when outside of the required cutting area.
Exceptions to these standard grades are stated under the captions of the respective species. Inspection shall be made from the better face. Sapwood is admitted. Any limitation of streaks and spots under Standard Inspection of the same species of lumber apply also to Strips. In the grade of Clear Strips, tapering pieces shall be measured at the narrow end. In the grade of Common Strips, tapering pieces shall be measured one-third the length of the piece from the narrow end. Shall have one clear face, the reverse side will admit wane or its equivalent in other defects, not exceeding one-third the length, one-third the width and onethird the thickness of the piece and shall otherwise be sound.
The reverse side of the cuttings will admit wane or its equivalent in other defects, not exceeding one-third the length, one-third the width and one-third the thickness of the piece and shall otherwise be sound.
Bevel on the clear face side of the piece in grades of Clear and Clear Sap shall be measured off. The reverse side will admit bevel or wane or their equivalent in other defects, not exceeding one-third the length, one-third the width and one-third the thickness of the piece and shall otherwise be sound.
Bevel on the face side of the piece in grades of No. The reverse side of the cuttings will admit bevel or wane or their equivalent in other defects, not exceeding one-third the length, one-third the width and one-third the thickness of the piece and shall otherwise be sound.
Pieces free of sapwood will admit one sound standard defect or its equivalent. All cuttings shall be the full width of the piece and clear both faces. Stain is admitted. Quartered Poplar No figure required. In FAS, mineral not exceeding one-sixth the surface of the piece in the aggregate will be admitted.
Slight stain will be admitted. There shall be not more than fifteen annual rings per inch. Splits in excess of the equivalent of two standard defects shall not be admitted. This rule does not apply to specified widths. Department of Commerce. The latest such standard, PS , serves as the basis for grade rules published by various regional associations covering species in different regions, ex.
The following rules have been included for the convenience of users of the specifications that preceded the National Grading Rule, PS , first published in
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