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TABLE 3: MECHANICALLY GRADED LUMBER
Based on 2002 SPIB Grading Rules
Values in pounds per square inch (psi)

Table 3 Mechanically Graded Lumber 2" thick or less, 2" and wider
Based on Normal Use Conditions (MC≤19%) See Tables A-1 thru A-4 for Adjustment Factors
Grade Designation¹	Extreme Fiber Stress in Bending F_b		Tension Parallel to Grain F_t	Horizontal Shear F_v^{3, 4}	Compression Perpendicular to Grain F_c⊥³	Compression Parallel to Grain F_c	Modulus of Elasticity E
Grade Designation¹	Single Member Uses	Repetitive Member Uses²	Tension Parallel to Grain F_t	Horizontal Shear F_v^{3, 4}	Compression Perpendicular to Grain F_c⊥³	Compression Parallel to Grain F_c	Modulus of Elasticity E
Machine Stress Rated (MSR) Lumber
1650f - 1.5E 1800f - 1.6E 1950f - 1.7E 2100f - 1.8E 2250f - 1.9E 2400f - 2.0E 2550f - 2.1E 2700f - 2.2E	1650 1800 1950 2100 2250 2400 2550 2700	1900 2070 2240 2420 2590 2760 2930 3110	1020 1175 1375 1575 1750 1925 2050 2150	175 175 175 190⁵ 190 190 190 190	565 565 565 805⁵ 805 805 805 805	1700 1750 1800 1875 1925 1975 2025 2100	1,500,000 1,600,000 1,700,000 1,800,000 1,900,000 2,000,000 2,100,000 2,200,000
Machine Evaluated Lumber (MEL)
M - 14 M - 19 M - 23 M - 26 M - 29 M - 30 M - 31	1800 2000 2400 2800 1550 2050 2850	2070 2300 2760 3220 1780 2360 3280	1000 1300 1900 1800 850 1050 1600	175 175 190⁵ 190 175 175 190	565 565 805⁵ 805 565 565 805	1750 1825 1975 2150 1650 1850 2150	1,700,000 1,600,000 1,800,000 2,000,000 1,700,000 1,700,000 1,900,000
(1) The most commonly produced Mechanically Graded Lumber grades are given here. See the SPIB Grading Rules for a complete listing of all MSR and MEL grades. (2) Repetitive member uses apply to joists, truss chords, rafters, studs, planks, decking or similar members which are in contact or spaced not more than 24" on center, are not less than three [3] in number, and are joined by floor, roof or other load distributing elements adequate to support the design load. The Repetitive Member Factor, C_r = 1.15, has been included in the listed Repetitive Member Use design values. (3) When a grade is qualified by test and quality controlled for specific gravity, the allowable horizontal shear and compression perpendicular-to-grain design values may be higher. See the SPIB Grading Rules for more details. (4) These shear design values are higher than those published in the 1997 NDS® Supplement: Design Values for Wood Construction. Design values, including these shear design values, should only be applied in conjunction with the appropriate design provisions in the NDS® . It it important, therefore, that these new shear design values be used only in conjunction with the new 2001 NDS®, and not the 1997 NDS® or earlier editions. (5) When not qualified for specific gravity, the grademark for mechanically graded lumber grades with a 1,800,000 psi modulus of elasticity design value shall include a specific gravity value of .55, a horizontal shear value of 175 psi, and a compression perpendicular-to-grain value of 565 psi.

Disclaimer: The Southern Pine Council™ does not test lumber or establish design values. The purpose of these tables is to collect and organize data available from other sources for the convenience of builders, engineers, architects and other professionals. The Southern Pine design values contained herein are taken from the Standard Grading Rules for Southern Pine Lumber, 2002 Edition, published by the Southern Pine Inspection Bureau, and the adjustment factors are taken from the National Design Specification® (NDS®) for Wood Construction, 2001 Edition, published by the American Forest & Paper Association. Neither the Southern Pine Council™, nor its members, warrant that the data from such sources on which the recommended uses of Southern Pine lumber contained herein are based is correct, and disclaim responsibility for injury or damage resulting from the use of such design values.

The conditions under which lumber is used in construction may vary widely, as does the quality of workmanship and construction methods. Neither the Southern Pine Council™, nor its members, have knowledge of the quality of the workmanship or construction methods used on any construction project, and, accordingly, do not warrant the design or performance of the lumber in completed structures.

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