SD453
• U5
U. S. Department of Agriculture, Forest Servic e
FOREST PRODUCTS LABORATOR Y
In cooperation with the University of Wisconsin
E.
MADISON, WISCONSIN
STRUCTURAL MATERIA L
Extract from "Recommended American Lumber Standard s
Softwood Lumber" Reported to the United States Departmen t
of Commerce by the Central Committee on Lumber Standards ,
Washington, D . C.
Adopted by the General Conference of Manufacturers
Distributors and Consumers May 1, 192 5
Washington, D . C .
(Extract from pages 8 to 10 "'Re-:ommexided. Ameri (sean L ime r
Standards Softwood Lumber" -- Reported to the United St,te E
D,:part .rent of Commerce by the Central Committee o n
? umber Standards, Washing ton, D . C .
Adopted by the General Conference of Manufacturers Dis trib_tors and Consumer May 1, 1925, at the DeparGmert o f
Commerce, Ndashington, D . C . )
IV . (40a and b) - BASIC PROVISIONS FOR THE SELECTION AND
INSPECTION OF SOFTWJOD DIMENSION AND TIMBERS WHER E
WORTS:iNCT STRESSES ARE REQUIRED .
The following basic provisions are to be used as base s
for the preparation of grading rules for structural materia l
by the Manufacturers, to be submitted by the Central Committee on Lumber Standards/for consideration as America n
Lumber Standards at the next General Conference in 1926 .
1.
GRADES AND CLASSIFICATION S
61 . Grades :
(a ) Dens e Selec t
(b ) Selec t
{a) Common
62 . Uses :
(a) Joist and Plank
Joists, Rafters, Scaffold Plank ,
Pa- tor .y' FI Cori ng, etc .
(b) Beams and Stringer s
Girders, Stringers, etc .
Beams,
(a) Pcsts and Timber s
Posts, Caps, Sills, Timbers, etc .
8810
1
2 . GENE'iAI, PROVISIO :TS
63. All grades shall contain only sound wood, unless ,
acoay is specifically permitted .
64. The measurement of c . knot shall be made, c he
section of the knot appearing on the surface unc.er consi d e
eration .
65. In Post and Timber gradee, and on the wide faces o f
Joist and Plank, the measure of a knot shall be on the mea n
or average diameter .
66. On the narrow faces of Joist and Plank and Beams and
Stringers, the size of a knot shall be taken as its width between lines parallel to the edges of the timber .
67. On the wide or vortical faces of Bears and Stringers ,
the smallest diameter of a knot shall be taken as its size .
68. Knots on the edgee of wide faces of Beams an d
Stringers are limited to the same size as on the adjacen t
narrow faces .
69. Knots on narrow faces and edges of wide faces o f
Joist and Plank and Beams and Stringers, may increase proportionately from the size allowed in the middle third t o
twice that size at the ends of the piece .
70. The size of knots on the wide faces of Toist an d
Plank and Beams and . Stringers, may increase proportionat e ly from the size allowed at the edge to that allowed a t
the center line .
71. Cluster knots and knots in groups are not permitted .
72. Knot holes and holes from other causes than knot s
shall be limited as provided for knots .
73. Shake shall be measured on the ends of a piece ,
and its size shall be taken as its width between line s
parallel to the wide faces of the piece . Checks and split s
shall be limited as provided for shakes . No checks or combinations of checks with shakes which would reduce th e
strength to a greater extent than the allowable shake shal l
be permitted .
74. No combination of wane and knots is permitted whic h
would reduce the strength more than the maximum allowabl e
knot .
75. No pieces of exceptionally lightweight shall b e
permitted in any grade, except that very light piece s
otherwise of Select grade may be accepted in the Commo n
grade .
76. No heartwood requirements are provided In thes e
grades . Heartwood requirements when ordered should b e
specified in terms of heartwood required on the girth or o n
each face, side or edge . Girth shall be measured at th e
point where the greatest amount of sapwood occurs .
77. Methods of measurement of Douglas fir and southern
pine for rate of growth and density are given for use wit h
the Dense Select and Select Grades .
78. Wane is permitted in all grades, but square edge s
may be specified when appearance or use requires .
R810
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3.
SELECTIOIN FOI-t RATE OF GROWTIh
Douglas Fir or Southern Pin e
70 . Douglas Fir or Southern Pine_ selected for clos e
main shall average . on eitler one end or the cchur not les s
then six nor more than twenty annual rings per inch, measured over a three-inch portion of a radial line representative of the average growth on the cross-section located a s
acscribed below .
When such radial line is not representative, it shal l
be shifted sufficiently to present a fair average, but th e
distance from the pith of the three-inch portion of the lin e
shall not be changed .
In case of disagreement two radial lines shall b e
chosen, and the number of rings shall 'oe the average o f
these lines .
Location of Radial Lin e
80. Douglas Fir . In side cut pieces the line shal l
be at a right angle to the annual rings and the center o f
the three-inch portion of the line shall be at the cente r
of the end of the p iece .
In boxed heart pieces the line shall run from th e
pith to the corner farthest from the pith . When the leas t
dimension is six inches or less the three-inch portion o f
the line shall begin at a distance of one inch from th e
pith . When the least dimension is more than six inche s
the three-inch portion of the line shall begin at a distance from the pith equal to two inches less than one-hal f
the least dimension of the piece .
If a three-inch portion of the radial line cannot b e
obtained the measurement shall be made over as much o f
the three-inch portion as is available .
81. Southern Pine .
In boxed heart pieces the rat e
of growth shall be counted over the third, fourth, an d
fifth inches from the pith along the radial line .
In eases whore timbers do not contain the pith, an d
it is impossible to locate it %itn any degree of accuracy ,
the same inspection shall bo made over three inches on an
approximate radial line beginning at the edge nearest th e
pith in timbers over three inches in thickness and on th e
second inch nearest to the pith in timbers three inche s
or less in thickness .
In material containing the pith but not a five-inc h
radial line, which is less than two inches°by eight inche s
in section or less than eight inches in width, that doe s
R810
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not show over sixteen square inches on the cross-section ,
the inspection shall apply to the second inch from the pitL_ .
In larger material that does not show a five-inch radial _JJn e
the inspection shall apply to the three inches farthest f rot .,
the pith .
4 . SELECTION FOR DENSIT Y
Douglas Fir. or Southern lin e
32 . Douglas Fir or Southern Pine selected for densit y
shall average on either one end or the other nct less tha n
six annual rings per inch and in addition one-third, or more ,
summerwood, over the same portion of a radial line as provided for selection for rate of growth . Coarse-grained material excluded by this rule shall be accepted as dense i f
averaging one-half, or more, summerwood .
The contrast in color between summerwood and spring wood shall be sharp and the summerwood shall be dark in color ,
except in pieces having considerably a')ove the minimum requirement for summerwood .
In case of disagreement two radial lines shall be chose n
and the summerwood and number of rings shall be the averag e
of these lines .
5 . JOIST AND PLANY
Joists, Rafters, Scaffold Plank, Factory Flooring, etc .
83 . Nominal thicknesses : 2" to 4" .
Nominal widths : 4" And wider .
Standard thicknesses, S1S or S2S ; 3/8" off .
Extra Standard thickness, 2", S1S or S2S : 1/4" off .
Standard widths, 2" to 7", S1E or S2E : 3/8" off .
8" and wider, S1E or S2E : 1/2" off .
Standard lengths : Multiples of two feet .
v
8810
4
S
Knots on Wide Face s
84.
t
Dense Select
Gddth On or near edge
of
middle third
face :
of length
:
3/4"
4"
6"
R'
1"
8rr
1-3/8"
1-3 / 4"
10"
12"
14"
Common
& Select
:Center line :On or near edge :Center lin e
: of face
middle third : of fac e
of lengt h
,
1"
l_3/4 "
1-1/4"
2"
2-1 / 2 "
1-1/2"
3-3 / 8 "
2-5/8"
2"
2-1/8"
2-3/8"
16"
2-1/2"
3-1/4"
4-1/4 "
5- 1 / 8 "
5-5/8 "
6"
2-1/2"
3"
3-1/4"
4-1/4"
3-3/8"
4-5/8"
85 . Knots on Narrow Faces of Boxe d , Heart Pieces ,
Middle Third of Lengt h
Thickness o f
Size of knot
piece
'Select
Common
-------------------------------------------------------------- 5/8"
1"
1-1/4"
2"
art
4"
7/8 u
1 - 1 /4 "
1-3/4 "
86 . Sum of Diameters of Knots . Center Half o f
Length on Any race, Not to Excee d
Dense Select & Select
Commo n
1-1/2 times width of face
Two times width of fac e
87.
Green
Seasoned
88.
Shakes and Checks
Dense Select & Select
Common
1/4 width of end
1/3 width of end
4/10 width of en d
4/9 width of end
Angle of Grain, Center Half of Lengt h
Dense Select & Select
Commo n
-1 in 12
R810
1 in 1 0
-5 -
Wan e
3 9.
Dense Select & Select
Commo n
1/8 thickness and/ .J: width 1/4 thickness ane/o :- widt h
90. Douglas fir cr southern pine Select grade -gin b e
selected for rate of growth .
Douglas fir or southsrn pine of Dense Select grace. t o
be selected for density .
o.
BEANS AND STR I1?C .hN S
Beams, Girders, Stringers, etc .
91. Nominal thicknesses : 5" and thicker .
Nominal widths : 8" and wider .
Standard lengths : Multiples cf two feet .
S1S, S1E, S2S or S43 : i/g " off each way .
92.
Knot s
Dense Select & Select
Common
Width :Narrow face . and:Center line :Narrow face and : Cente r
of : edge of wid e
of
: edge of wide :line o f
face : face middle : wide face : face middl e :wide fac e
:third of length :
:third of length :
5"
6"
8"
10"
12"
14"
16"
18"
20"
22"
24"
R81 0
1 1/4 "
1 1/2"
1 3/4"
2"
2 1/8"
2 1/4"
2 3/8"
1 1/2"
2"
2 1/2"
3"
3 1/4"
3 3/8"
3 5/8 "
3 7/8"
4" '
4 1/4"
2"
2 3/8"
2 3/4
3 1/8"
3 3/8"
3 5/8"
3 7/8"
2 3/8 "
3 1/8 "
4"
4 3/4 "
5 1/8 "
5 1/2 "
5 7/8 "
6 1/8 "
6 1/2 "
6 3/4"
ium -af- DIalmet e o f KI.Lots, C-a .5er Half_ of Length
on Lty li aGse-Not to 'EXese d
;gin
Se" tact % Selec t
vf idth Lf face
,ir4t=, h
1/2.
Mkei ee-ic, Check e
Donee Select
Scaf-Iled
95 .
fac e
.(t.
. Csmmol;
°e, Select
1/4 width of end
1/3 width cif end
14.7(2
.4/10 width
4/9. width
.oaf
crier,
cpd,
Grain, Center Half of Leng .th .
Angle
Dense- Select, 8c Select
.-
C'emmo n
1 in 10
1 in 15
96.
Wane ' .
Dense Select
.
CommOn
Select
1/8 thicknes's and/or.
.
1
width 1/4 thickness an/or width
97. Douglas' fir or southern pine S_e3:eet grade to be
selected for rate of growth .
Douglas fir or southern ,pine of Dense Select grade t o
. be selected for density .
-,.:
!. -
,
7 . POSTS AID, TIT 3ER S
Posts, Caps, Sills, Timbers, eto.
N.
96 .
Nominal sizes : 6" x 6" and larger .
Standard
lengths : Multiples of two feet, .
.,
SIS,-
R810
S2S or S4S : 1/2" off each ,way .
7
-, ;.
4.
99 .
Kxlot3
Width of face
Size of knot s
:Dense Select ' & Select :
Common
eel
3 1/8 rr
"
2 1/2"
3"
31/4"
3 3/8"
1C"
12"
14"
16"
18"
20"
22"
24"
4"
4 3/4 "
5 1/8 "
5 1/2
3 5/8"
3 7/o'
4"
4 1/4"
5
6
6
6
7/8 "
1/8 "
1/2 "
3/4"
100.
Sum of diameters of all knots within any 6" o f
length not to exceed twice size 'of maximum knot allowable ;
nor to be two of maximum allowable knots in same 6" of
length on any one face .
101.
Shakes and Checks
Dense Select & Select
Green
Seasoned 4/10 width of end
1/2 width of end
102 .
Common
1/2 width of end
6/10 width of en d
Angle of Grai n
Dense Select & Select
1 in 10
103.
Common
1 in 8
Wane
Dense Select & Select
1/8 thickness and/off ; width
Common
1/4 thickness and/oqo vdth
104. Douglas fir or southern pine Select grade to b e
selected for rate of growth .
Douglas fir' or southern pine of ''ense Select grai.e t o
be selected for density .