Design of Fire-Resistive Exposed Wood Members
Designers, regulators, and fire officials throughout the country recognize the superior fire resistance demonstrated by structural wood beams
and columns in actual fires. This document provides a simplified description of a code-approved
fire design procedure for exposed wood members.
These general fire design provisions are given in
Chapter 16 of the 2012 National Design Specification® for Wood Construction (NDS®), which
is referenced in Section 722.1 of the 2012 International Building Code (IBC) as a method of calculating fire resistance of exposed wood members. A more comprehensive discussion of this
mechanics-based design procedure can be found
in a separate document entitled Calculating the Fire
Resistance of Exposed Wood Members: Technical Report No. 10 available from the American Wood
Council.
Char Rate and Char Depth
Prior to the development of the mechanics-based
design procedure presented in this document, the codeaccepted method for calculating fire resistance of exposed wood members was based on empirical solutions
fit to beam and column test data. The newer mechanicsbased design procedure presented herein permits the
calculation of fire resistance for a greater range of loading conditions, fire exposures, and member sizes.
Member design is based on reduced section properties
of the residual (uncharred) section, which is determined
by subtracting a dimension equal to the effective char
depth normal to each exposed surface. Char depth is
calculated using an assumed effective char rate that varies non-linearly with respect to time, t. The effective
Copyright © 2014 American Wood Council
2
DESIGN OF FIRE-RESISTIVE EXPOSED WOOD MEMBERS
char rate, eff, and effective char depth, achar, are calculated as follows:
(1)
(2)
In these equations, the term  n is the nominal char
rate, which is based on a 1-hour fire exposure time.
For most wood members, the nominal char rate is assumed to be 1.5 in./hr. The following table gives effective char rates, eff, and effective char depth, achar, corresponding to a nominal char rate, n, of 1.5 in./hr:
Fire Exposure
Time, t
(hours)
Effective Char
Rate,  eff
(in./hr)
Effective Char
Depth, achar
(in.)
1
1.5
2
1.8
1.67
1.58
1.8
2.5
3.2
exposure (e.g., protected by the underside of a floor or
roof). These tabulated values apply to flexural members that are loaded in bending about one axis only,
and are continuously laterally supported along the
compression edge. The dimension “d” is the actual
cross-sectional dimension measured in the direction
normal to the axis about which bending occurs, and is
not necessarily greater than “b” (see Figure 1).
Figure 1 Flexural Member Cross-Section
Simple Design Procedure – Load Ratio
Tables
For members stressed in one principle direction,
simplifications can be made which allow the creation
of load ratio tables. These load ratio tables can be used
to determine the structural design load ratio, Rs, at
which the member has sufficient capacity for a given
fire resistance time. The following tables give load
ratios corresponding to 1-hour, 1½-hour and 2-hour
fire resistance ratings for specified member dimensions. All tabulated load ratios apply to standard reference conditions where the load duration factor, wet
service factor and temperature factor equal 1.0
(CD=1.0; CM=1.0; Ct=1.0). For more complex calculations where stress interactions must be considered, or
where standard reference conditions do not apply, the
user should use the provisions of Technical Report No.
10, along with the appropriate NDS provisions.
For fire design, the following condition must be
satisfied:
Where:
Flexural Members
Design load ratios, Rs, for fire design of flexural
members are given in Table 1A(1-hr), Table 1B(1.5hr) and Table 1C(2-hr) for 1-hour, 1.5-hour and 2-hour
fire resistance ratings, respectively. The Rs values given in these tables apply to three-sided exposure in
which the top edge of the beam is protected from fire
American Wood Council
Rs = Design load ratio [see Table 1A(1-hr),
Table 1B(1.5-hr) and Table 1C(2-hr)]
M = ASD design moment on the flexural member (in.-lbs)
Fb' = Adjusted ASD bending design value used
in structural calculations (psi)
S = Section modulus using full (uncharred)
cross-section dimensions (in.3)
DESIGN OF FIRE-RESISTIVE EXPOSED WOOD MEMBERS
Table 1A(1-hr)
3
Design Load Ratios, Rs, for Flexural Members Exposed on Three Sides1,2,3,4
1 – HOUR RATING (Structural Calculations at Standard Reference Conditions: C D=1.0, CM=1.0, Ct=1.0, Ci=1.0, CL=1.0)
(Protected Surface Along Width, b, on Top Edge; With Continuous Lateral Support)
Width, b
5 1/2
6
6 3/4
6 7/8
7 1/4
7 1/2
8 1/4
8 1/2
8 3/4
5 1/2
6
6 3/4
6 7/8
7 1/4
7 1/2
8 1/4
8 1/2
8 3/4
9
9 1/4
9 5/8
10 1/2
10 3/4
11
11 1/4
12
12 1/4
12 3/8
13 1/4
13 1/2
13 3/4
15
15 1/8
16 1/2
17
17 7/8
18
19
19 1/4
19 1/2
20 5/8
21
22
22 1/2
23
23 3/8
24
30
36
60
1.
2.
3.
4.
9
9 1/4
9 5/8
10 1/2
10 3/4
11
11 1/4
12
12 1/4
12 3/8
13 1/4
13 1/2
13 3/4
15
0.87
0.94
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.88
0.95
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.90
0.98
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.91
0.99
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.91
0.99
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.94
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.95
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.95
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.98
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
Design Load Ratio, Rs
Depth, d
0.45
0.48
0.53
0.54
0.56
0.57
0.60
0.61
0.62
0.63
0.64
0.65
0.68
0.68
0.69
0.69
0.71
0.72
0.72
0.74
0.74
0.74
0.76
0.76
0.78
0.79
0.80
0.80
0.81
0.81
0.81
0.82
0.82
0.83
0.83
0.84
0.84
0.84
0.87
0.89
0.93
0.52
0.56
0.61
0.62
0.64
0.66
0.70
0.71
0.72
0.73
0.74
0.75
0.78
0.79
0.80
0.80
0.82
0.83
0.83
0.85
0.86
0.86
0.88
0.88
0.90
0.91
0.92
0.92
0.93
0.94
0.94
0.95
0.95
0.96
0.96
0.97
0.97
0.98
1.00
1.00
1.00
0.60
0.65
0.72
0.72
0.75
0.77
0.81
0.83
0.84
0.85
0.86
0.88
0.91
0.92
0.93
0.94
0.96
0.97
0.97
0.99
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.61
0.67
0.73
0.74
0.77
0.78
0.83
0.84
0.86
0.87
0.88
0.90
0.93
0.94
0.95
0.96
0.98
0.99
0.99
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.65
0.70
0.77
0.78
0.81
0.83
0.88
0.89
0.91
0.92
0.93
0.95
0.99
0.99
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.67
0.73
0.80
0.81
0.84
0.86
0.91
0.92
0.93
0.95
0.96
0.98
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.73
0.79
0.86
0.88
0.91
0.93
0.98
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.74
0.81
0.88
0.90
0.93
0.95
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.76
0.82
0.90
0.91
0.95
0.97
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.77
0.84
0.92
0.93
0.97
0.99
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.79
0.85
0.94
0.95
0.98
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.81
0.87
0.96
0.97
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.85
0.92
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.86
0.93
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
Design load ratios (Rs) assume bending about the X-X axis, and continuous lateral support along the compression edge.
Design load ratios (Rs) may be interpolated for widths (b) and depths (d) other than those shown.
For the purposes of this table, the dimension d is measured in the direction normal to the axis about which bending occurs. The dimensions d and b are dressed, dry dimensions.
The design moment for fire, Fb,f'Sf, is approximated by multiplying the adjusted ASD design moment used in structural design, Fb'S, by Rs. (Fb,f’Sf = Fb'S Rs)
American Wood Council
4
DESIGN OF FIRE-RESISTIVE EXPOSED WOOD MEMBERS
Table 1B(1.5-hr)
Design Load Ratios, Rs, for Flexural Members Exposed on Three Sides1,2,3,4
1.5 – HOUR RATING (Structural Calculations at Standard Reference Conditions: CD=1.0, CM=1.0, Ct=1.0, Ci=1.0, CL=1.0)
(Protected Surface Along Width, b, on Top Edge; With Continuous Lateral Support)
Width, b
6 3/4
6 7/8
7 1/4
7 1/2
8 1/4
8 1/2
8 3/4
9
9 1/4
5 1/2
6
6 3/4
6 7/8
7 1/4
7 1/2
8 1/4
8 1/2
8 3/4
9
9 1/4
9 5/8
10 1/2
10 3/4
11
11 1/4
12
12 1/4
12 3/8
13 1/4
13 1/2
13 3/4
15
15 1/8
16 1/2
17
17 7/8
18
19
19 1/4
19 1/2
20 5/8
21
22
22 1/2
23
23 3/8
24
30
36
60
1.
2.
3.
4.
9 5/8
10 1/2
10 3/4
11
11 1/4
12
12 3/8
13 1/4
13 3/4
15
16 1/2
18
24
36
0.49
0.56
0.66
0.67
0.71
0.74
0.81
0.83
0.85
0.87
0.88
0.91
0.96
0.98
0.99
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.50
0.58
0.67
0.69
0.73
0.75
0.82
0.84
0.87
0.88
0.90
0.93
0.98
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.53
0.60
0.70
0.72
0.76
0.79
0.86
0.88
0.90
0.92
0.94
0.97
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.54
0.62
0.72
0.73
0.78
0.80
0.88
0.90
0.92
0.94
0.96
0.99
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.56
0.65
0.75
0.77
0.81
0.84
0.92
0.95
0.97
0.99
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.59
0.67
0.79
0.80
0.85
0.88
0.96
0.99
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.61
0.70
0.81
0.83
0.88
0.91
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.67
0.77
0.89
0.91
0.97
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.73
0.83
0.97
0.99
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
Design Load Ratio, Rs
Depth, d
0.22
0.25
0.29
0.30
0.32
0.33
0.36
0.37
0.38
0.38
0.39
0.40
0.43
0.43
0.44
0.45
0.46
0.47
0.47
0.48
0.49
0.49
0.51
0.51
0.53
0.54
0.54
0.55
0.56
0.56
0.56
0.57
0.57
0.58
0.58
0.58
0.59
0.59
0.62
0.64
0.68
0.23
0.26
0.31
0.31
0.33
0.34
0.38
0.39
0.40
0.40
0.41
0.42
0.45
0.46
0.46
0.47
0.49
0.49
0.49
0.51
0.51
0.52
0.54
0.54
0.56
0.56
0.57
0.57
0.58
0.59
0.59
0.60
0.60
0.61
0.61
0.62
0.62
0.62
0.65
0.67
0.71
0.26
0.30
0.35
0.36
0.38
0.39
0.43
0.44
0.45
0.46
0.47
0.48
0.51
0.52
0.53
0.53
0.55
0.56
0.56
0.58
0.59
0.59
0.61
0.61
0.63
0.64
0.65
0.65
0.67
0.67
0.67
0.68
0.68
0.69
0.70
0.70
0.70
0.71
0.74
0.76
0.81
0.28
0.32
0.38
0.38
0.41
0.42
0.46
0.47
0.48
0.49
0.50
0.52
0.55
0.56
0.57
0.57
0.59
0.60
0.60
0.62
0.63
0.63
0.66
0.66
0.68
0.69
0.70
0.70
0.71
0.72
0.72
0.73
0.74
0.74
0.75
0.75
0.76
0.76
0.80
0.82
0.87
0.33
0.38
0.44
0.45
0.48
0.50
0.54
0.56
0.57
0.58
0.60
0.61
0.65
0.66
0.67
0.68
0.70
0.71
0.71
0.74
0.74
0.75
0.78
0.78
0.81
0.82
0.83
0.83
0.84
0.85
0.85
0.87
0.87
0.88
0.89
0.89
0.89
0.90
0.94
0.97
1.00
0.35
0.40
0.46
0.47
0.50
0.52
0.57
0.58
0.60
0.61
0.62
0.64
0.68
0.69
0.70
0.71
0.73
0.74
0.75
0.77
0.78
0.78
0.81
0.82
0.84
0.85
0.87
0.87
0.88
0.89
0.89
0.90
0.91
0.92
0.93
0.93
0.93
0.94
0.98
1.00
1.00
0.36
0.41
0.48
0.49
0.52
0.54
0.59
0.61
0.62
0.64
0.65
0.67
0.71
0.72
0.73
0.74
0.76
0.77
0.78
0.80
0.81
0.82
0.85
0.85
0.88
0.89
0.90
0.90
0.92
0.92
0.93
0.94
0.95
0.96
0.96
0.97
0.97
0.98
1.00
1.00
1.00
0.38
0.43
0.50
0.51
0.54
0.56
0.61
0.63
0.64
0.66
0.67
0.69
0.73
0.74
0.75
0.76
0.79
0.80
0.80
0.83
0.84
0.85
0.88
0.88
0.91
0.92
0.94
0.94
0.95
0.96
0.96
0.98
0.98
0.99
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.39
0.44
0.52
0.53
0.56
0.58
0.63
0.65
0.67
0.68
0.70
0.72
0.76
0.77
0.78
0.79
0.82
0.83
0.83
0.86
0.87
0.87
0.91
0.91
0.94
0.95
0.97
0.97
0.99
0.99
0.99
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.41
0.46
0.54
0.55
0.59
0.61
0.66
0.68
0.70
0.71
0.73
0.75
0.79
0.81
0.82
0.83
0.86
0.87
0.87
0.90
0.91
0.92
0.95
0.95
0.98
0.99
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.44
0.51
0.59
0.60
0.64
0.66
0.72
0.74
0.76
0.78
0.79
0.82
0.87
0.88
0.89
0.90
0.93
0.94
0.95
0.98
0.99
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.45
0.52
0.60
0.62
0.65
0.68
0.74
0.76
0.78
0.79
0.81
0.83
0.88
0.90
0.91
0.92
0.95
0.96
0.97
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.46
0.53
0.61
0.63
0.67
0.69
0.75
0.77
0.79
0.81
0.83
0.85
0.90
0.91
0.93
0.94
0.97
0.98
0.99
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.47
0.54
0.63
0.64
0.68
0.70
0.77
0.79
0.81
0.82
0.84
0.87
0.92
0.93
0.94
0.96
0.99
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
Design load ratios (Rs) assume bending about the X-X axis, and continuous lateral support along the compression edge.
Design load ratios (Rs) may be interpolated for widths (b) and depths (d) other than those shown.
For the purposes of this table, the dimension d is measured in the direction normal to the axis about which bending occurs. The dimensions d and b are dressed, dry dimensions.
The design moment for fire, Fb,f'Sf, is approximated by multiplying the adjusted ASD design moment used in structural design, Fb'S, by Rs. (Fb,f'Sf = Fb'S Rs)
American Wood Council
DESIGN OF FIRE-RESISTIVE EXPOSED WOOD MEMBERS
Table 1C(2-hr)
5
Design Load Ratios, Rs, for Flexural Members Exposed on Three Sides1,2,3,4
2 – HOUR RATING (Structural Calculations at Standard Reference Conditions: CD=1.0, CM=1.0, Ct=1.0, Ci=1.0, CL=1.0)
(Protected Surface Along Width, b, on Top Edge; With Continuous Lateral Support)
Width, b
8 1/2
8 3/4
9
9 1/4
9 5/8
10 1/2
10 3/4
11
11 1/4
5 1/2
6
6 3/4
6 7/8
7 1/4
7 1/2
8 1/4
8 1/2
8 3/4
9
9 1/4
9 5/8
10 1/2
10 3/4
11
11 1/4
12
12 1/4
12 3/8
13 1/4
13 1/2
13 3/4
15
15 1/8
16 1/2
17
17 7/8
18
19
19 1/4
19 1/2
20 5/8
21
22
22 1/2
23
23 3/8
24
30
36
60
1.
2.
3.
4.
12
12 3/8
13 1/4
13 1/2
13 3/4
15
16 1/2
17
18
21
24
36
48
60
0.30
0.37
0.47
0.48
0.52
0.55
0.63
0.65
0.67
0.69
0.71
0.74
0.80
0.82
0.84
0.85
0.89
0.91
0.91
0.96
0.97
0.98
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.32
0.39
0.50
0.51
0.56
0.59
0.67
0.69
0.72
0.74
0.76
0.79
0.86
0.88
0.89
0.91
0.95
0.97
0.97
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.32
0.40
0.51
0.52
0.57
0.60
0.68
0.71
0.73
0.75
0.78
0.81
0.87
0.89
0.91
0.92
0.97
0.98
0.99
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.33
0.41
0.52
0.54
0.59
0.62
0.70
0.73
0.75
0.78
0.80
0.83
0.90
0.92
0.94
0.96
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.36
0.45
0.56
0.58
0.63
0.67
0.76
0.79
0.81
0.84
0.86
0.90
0.97
0.99
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.38
0.47
0.59
0.61
0.67
0.70
0.80
0.83
0.86
0.88
0.91
0.95
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.42
0.53
0.66
0.69
0.75
0.79
0.89
0.93
0.96
0.99
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.45
0.55
0.70
0.72
0.79
0.83
0.94
0.98
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.46
0.57
0.72
0.74
0.81
0.85
0.97
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
Design Load Ratio, Rs
Depth, d
0.13
0.16
0.21
0.21
0.23
0.24
0.28
0.29
0.30
0.31
0.32
0.33
0.36
0.36
0.37
0.38
0.40
0.40
0.40
0.42
0.43
0.43
0.45
0.46
0.48
0.48
0.49
0.50
0.51
0.51
0.51
0.52
0.53
0.53
0.54
0.54
0.55
0.55
0.58
0.61
0.65
0.14
0.18
0.22
0.23
0.25
0.26
0.30
0.31
0.32
0.33
0.34
0.36
0.39
0.39
0.40
0.41
0.43
0.43
0.44
0.46
0.46
0.47
0.49
0.49
0.52
0.52
0.54
0.54
0.55
0.55
0.55
0.57
0.57
0.58
0.58
0.59
0.59
0.60
0.63
0.66
0.71
0.15
0.19
0.24
0.25
0.27
0.28
0.32
0.33
0.35
0.36
0.37
0.38
0.41
0.42
0.43
0.44
0.46
0.47
0.47
0.49
0.50
0.50
0.53
0.53
0.55
0.56
0.57
0.58
0.59
0.59
0.59
0.61
0.61
0.62
0.63
0.63
0.63
0.64
0.68
0.70
0.76
0.16
0.20
0.25
0.26
0.29
0.30
0.34
0.36
0.37
0.38
0.39
0.41
0.44
0.45
0.46
0.47
0.49
0.50
0.50
0.52
0.53
0.53
0.56
0.56
0.59
0.60
0.61
0.61
0.63
0.63
0.63
0.65
0.65
0.66
0.67
0.67
0.67
0.68
0.72
0.75
0.81
0.18
0.22
0.28
0.28
0.31
0.33
0.37
0.39
0.40
0.41
0.42
0.44
0.48
0.49
0.50
0.51
0.53
0.54
0.54
0.57
0.57
0.58
0.61
0.61
0.64
0.65
0.66
0.66
0.68
0.68
0.69
0.70
0.71
0.72
0.72
0.73
0.73
0.74
0.78
0.81
0.88
0.20
0.25
0.32
0.33
0.36
0.38
0.43
0.45
0.46
0.48
0.49
0.51
0.55
0.56
0.58
0.59
0.61
0.62
0.63
0.66
0.66
0.67
0.71
0.71
0.74
0.75
0.77
0.77
0.79
0.79
0.80
0.81
0.82
0.83
0.84
0.84
0.85
0.85
0.91
0.94
1.00
0.21
0.26
0.33
0.34
0.37
0.39
0.45
0.46
0.48
0.49
0.51
0.53
0.57
0.58
0.60
0.61
0.64
0.65
0.65
0.68
0.69
0.70
0.73
0.73
0.77
0.78
0.79
0.80
0.82
0.82
0.82
0.84
0.85
0.86
0.87
0.87
0.88
0.88
0.94
0.98
1.00
0.22
0.27
0.34
0.35
0.39
0.41
0.46
0.48
0.49
0.51
0.52
0.55
0.59
0.60
0.61
0.63
0.66
0.67
0.67
0.70
0.71
0.72
0.75
0.76
0.79
0.80
0.82
0.82
0.84
0.85
0.85
0.87
0.87
0.89
0.89
0.90
0.91
0.91
0.97
1.00
1.00
0.23
0.28
0.35
0.36
0.40
0.42
0.47
0.49
0.51
0.52
0.54
0.56
0.61
0.62
0.63
0.64
0.68
0.69
0.69
0.72
0.73
0.74
0.78
0.78
0.82
0.83
0.85
0.85
0.87
0.87
0.88
0.89
0.90
0.91
0.92
0.93
0.93
0.94
1.00
1.00
1.00
0.24
0.30
0.38
0.39
0.43
0.45
0.51
0.53
0.55
0.57
0.58
0.61
0.66
0.67
0.68
0.70
0.73
0.74
0.75
0.78
0.79
0.80
0.84
0.84
0.88
0.89
0.91
0.92
0.94
0.94
0.95
0.97
0.97
0.99
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.25
0.31
0.39
0.41
0.44
0.47
0.53
0.55
0.57
0.59
0.60
0.63
0.68
0.69
0.71
0.72
0.76
0.77
0.77
0.81
0.82
0.83
0.87
0.87
0.91
0.92
0.94
0.95
0.97
0.97
0.98
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.27
0.33
0.42
0.43
0.47
0.50
0.57
0.59
0.61
0.63
0.65
0.67
0.73
0.74
0.76
0.77
0.81
0.82
0.83
0.86
0.87
0.88
0.93
0.93
0.97
0.99
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.27
0.34
0.43
0.44
0.48
0.51
0.58
0.60
0.62
0.64
0.66
0.68
0.74
0.75
0.77
0.78
0.82
0.83
0.84
0.88
0.89
0.90
0.94
0.95
0.99
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.28
0.34
0.43
0.45
0.49
0.51
0.59
0.61
0.63
0.65
0.67
0.69
0.75
0.77
0.78
0.80
0.83
0.85
0.85
0.89
0.90
0.91
0.96
0.96
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
Design load ratios (Rs) assume bending about the X-X axis, and continuous lateral support along the compression edge.
Design load ratios (Rs) may be interpolated for widths (b) and depths (d) other than those shown.
For the purposes of this table, the dimension d is measured in the direction normal to the axis about which bending occurs. The dimensions d and b are dressed, dry dimensions.
The design moment for fire, Fb,f'Sf, is approximated by multiplying the adjusted ASD design moment used in structural design, Fb'S, by Rs. (Fb,f'Sf = Fb'S Rs)
American Wood Council
6
DESIGN OF FIRE-RESISTIVE EXPOSED WOOD MEMBERS
Compression Members
Design load ratios, Rs, for fire design of columns
are calculated as the product of Rs1 and Rs2, which are
given in Table 2A(1-hr), Table 2B(1.5-hr) and Table
2C(2-hr) for 1-hour, 1.5-hour and 2-hour fire resistance ratings, respectively. For cases in which the
product of Rs1 and Rs2 is greater than 1.0, Rs should be
taken as 1.0. These tables apply to cases in which all
four sides are exposed to the fire; however, values calculated using these design load ratios may be conservatively applied to cases in which one or more sides of
the column are protected. Both d and b represent the
dry dressed cross-sectional dimensions of the column.
The dimension “d” is the actual dimension measured
in the direction perpendicular to the axis about which
buckling is being considered, and is not necessarily
greater than “b” (see Figure 2). The designer should
consider buckling about both axes and use the lesser
design value.
Figure 2 Compression Member Cross-Section
The tabulated Rs1 values are calculated based on a
square column cross-section having dimensions d by
d, and therefore must be multiplied by Rs2 for any column that is not square. Where b is less than d, Rs2 will
be less than 1.0; and where b is greater than d, Rs2 will
be greater than 1.0. The Rs1 values are derived using
the more conservative value of the parameter “c” from
equation 3.7-1 of the NDS (for long columns, c = 0.9
results in lower Rs1 values; for short columns, c = 0.8
results in lower Rs1 values). This allows the design
load ratios to be used with sawn lumber, structural
glued laminated timber, or structural composite lumber. The Rs1 values are also based on the assumption
that Emin'/Fc*= 350. Because of this, the design load
ratios, Rs, may conservatively be used for all species
and grades where the ratio of Emin' to Fc* is greater
than or equal to 350.
For fire design, the following condition must be
satisfied:
Where:
Rs = (Rs1)(Rs2) ≤ 1.0 [see Table 2A(1-hr), Table
2B(1.5-hr) and Table 2C(2-hr)]
P = Total ASD design axial load on the column
(lbs)
Fc' = Adjusted ASD compression design value
used in structural calculations (psi)
A = Area of cross section using full (uncharred) dimensions (in.2)
American Wood Council
DESIGN OF FIRE-RESISTIVE EXPOSED WOOD MEMBERS
7
Design Load Ratios, Rs = (Rs1)( Rs2) ≤ 1.0, for Compression Members Exposed on Four Sides1,2,3,4
Table 2A(1-hr)
1 – HOUR RATING (Structural Calculations at Standard Reference Conditions: CD=1.0, CM=1.0, Ct=1.0, Ci=1.0)
Depth of Member, d (measured in the direction normal to the axis about which buckling is considered)
5-1/2
6
6-3/4
6-7/8
7-1/4
7-1/2
8-1/4
8-1/2
Le/d
0.31
0.30
0.26
0.19
0.12
0.084
0.061
0.048
0.040
0.036
0.033
0.032
0.031
0.031
0.030
0.030
0.029
0.029
0.41
0.40
0.37
0.29
0.21
0.15
0.11
0.086
0.072
0.064
0.060
0.057
0.056
0.055
0.054
0.054
0.053
0.053
0.56
0.55
0.52
0.45
0.35
0.26
0.20
0.16
0.13
0.12
0.11
0.11
0.10
0.10
0.10
0.10
0.098
0.097
0.59
0.58
0.55
0.48
0.38
0.28
0.22
0.17
0.14
0.13
0.12
0.12
0.11
0.11
0.11
0.11
0.11
0.11
0.65
0.65
0.62
0.55
0.45
0.35
0.27
0.21
0.18
0.16
0.15
0.14
0.14
0.14
0.14
0.14
0.13
0.13
0.70
0.69
0.66
0.60
0.50
0.39
0.30
0.24
0.20
0.18
0.17
0.16
0.16
0.16
0.16
0.15
0.15
0.15
0.82
0.81
0.79
0.73
0.63
0.51
0.41
0.33
0.28
0.25
0.23
0.22
0.22
0.22
0.21
0.21
0.21
0.21
0.86
0.85
0.83
0.77
0.67
0.55
0.44
0.36
0.30
0.27
0.25
0.25
0.24
0.24
0.23
0.23
0.23
0.23
1.00
1.16
1.35
1.38
1.46
1.51
1.63
1.67
1.70
1.74
1.77
1.81
1.90
1.93
1.95
1.97
2.03
2.20
2.32
2.40
2.46
2.61
0.86
1.00
1.17
1.19
1.26
1.30
1.41
1.44
1.47
1.50
1.53
1.56
1.64
1.66
1.68
1.70
1.75
1.90
2.00
2.07
2.13
2.25
0.74
0.86
1.00
1.02
1.08
1.11
1.21
1.24
1.26
1.29
1.31
1.34
1.41
1.43
1.44
1.46
1.50
1.63
1.71
1.78
1.82
1.93
0.73
0.84
0.98
1.00
1.06
1.09
1.18
1.21
1.24
1.26
1.28
1.31
1.38
1.40
1.41
1.43
1.47
1.60
1.68
1.74
1.78
1.89
0.69
0.79
0.93
0.95
1.00
1.03
1.12
1.15
1.17
1.19
1.21
1.24
1.31
1.32
1.34
1.35
1.39
1.51
1.59
1.65
1.69
1.79
0.66
0.77
0.90
0.92
0.97
1.00
1.08
1.11
1.13
1.15
1.17
1.20
1.26
1.28
1.29
1.31
1.35
1.46
1.54
1.59
1.63
1.73
0.61
0.71
0.83
0.85
0.89
0.92
1.00
1.02
1.04
1.06
1.08
1.11
1.17
1.18
1.19
1.21
1.24
1.35
1.42
1.47
1.51
1.60
0.60
0.69
0.81
0.83
0.87
0.90
0.98
1.00
1.02
1.04
1.06
1.09
1.14
1.15
1.17
1.18
1.21
1.32
1.39
1.44
1.47
1.56
b
9-1/4
9-5/8
10-1/2
10-3/4
11
11-1/4
12
15
18
21
24
36
0.89
0.89
0.86
0.81
0.71
0.59
0.48
0.39
0.33
0.29
0.28
0.27
0.26
0.26
0.25
0.25
0.25
0.25
0.93
0.92
0.90
0.85
0.75
0.63
0.51
0.42
0.35
0.32
0.30
0.29
0.28
0.28
0.27
0.27
0.27
0.27
0.96
0.96
0.93
0.88
0.79
0.66
0.55
0.45
0.38
0.34
0.32
0.31
0.30
0.30
0.29
0.29
0.29
0.29
1.01
1.00
0.98
0.93
0.84
0.72
0.59
0.49
0.42
0.38
0.35
0.34
0.33
0.33
0.32
0.32
0.32
0.31
1.11
1.11
1.09
1.04
0.96
0.83
0.70
0.59
0.50
0.45
0.43
0.41
0.40
0.40
0.39
0.39
0.38
0.38
1.14
1.14
1.11
1.07
0.99
0.86
0.73
0.61
0.53
0.48
0.45
0.43
0.42
0.42
0.41
0.41
0.40
0.40
1.17
1.16
1.14
1.10
1.01
0.89
0.76
0.64
0.55
0.50
0.47
0.45
0.44
0.44
0.43
0.43
0.42
0.42
1.19
1.19
1.17
1.12
1.04
0.92
0.79
0.67
0.57
0.52
0.49
0.47
0.46
0.45
0.45
0.45
0.44
0.44
1.26
1.26
1.24
1.20
1.12
1.00
0.87
0.74
0.64
0.58
0.55
0.53
0.52
0.51
0.51
0.50
0.49
0.49
1.49
1.49
1.47
1.43
1.37
1.26
1.13
1.00
0.87
0.80
0.75
0.73
0.71
0.71
0.70
0.70
0.69
0.68
1.65
1.65
1.63
1.60
1.54
1.45
1.32
1.19
1.06
0.97
0.92
0.89
0.87
0.86
0.86
0.85
0.84
0.84
1.77
1.77
1.75
1.72
1.67
1.58
1.46
1.33
1.20
1.11
1.05
1.02
1.00
0.99
0.98
0.98
0.97
0.96
1.86
1.86
1.85
1.82
1.77
1.69
1.58
1.45
1.32
1.22
1.16
1.13
1.11
1.10
1.09
1.08
1.07
1.07
2.09
2.09
2.08
2.05
2.01
1.95
1.85
1.73
1.61
1.50
1.44
1.41
1.38
1.37
1.36
1.36
1.34
1.34
0.51
0.59
0.69
0.70
0.74
0.76
0.83
0.85
0.87
0.88
0.90
0.92
0.97
0.98
0.99
1.00
1.03
1.12
1.18
1.22
1.25
1.32
0.49
0.57
0.67
0.68
0.72
0.74
0.81
0.82
0.84
0.86
0.87
0.89
0.94
0.95
0.96
0.97
1.00
1.09
1.14
1.18
1.21
1.29
0.45
0.53
0.61
0.63
0.66
0.68
0.74
0.76
0.77
0.79
0.80
0.82
0.86
0.88
0.89
0.89
0.92
1.00
1.05
1.09
1.12
1.18
0.43
0.50
0.58
0.60
0.63
0.65
0.70
0.72
0.74
0.75
0.76
0.78
0.82
0.83
0.84
0.85
0.88
0.95
1.00
1.04
1.06
1.13
0.42
0.48
0.56
0.57
0.61
0.63
0.68
0.70
0.71
0.72
0.74
0.76
0.79
0.80
0.81
0.82
0.84
0.92
0.97
1.00
1.03
1.09
0.41
0.47
0.55
0.56
0.59
0.61
0.66
0.68
0.69
0.71
0.72
0.74
0.77
0.78
0.79
0.80
0.82
0.89
0.94
0.97
1.00
1.06
0.38
0.44
0.52
0.53
0.56
0.58
0.63
0.64
0.65
0.67
0.68
0.70
0.73
0.74
0.75
0.76
0.78
0.84
0.89
0.92
0.94
1.00
Rs2 - Design Stress Adjustment for Width, b, of Column
5-1/2
6
6-3/4
6-7/8
7-1/4
7-1/2
8-1/4
8-1/2
8-3/4
9
9-1/4
9-5/8
10-1/2
10-3/4
11
11-1/4
12
15
18
21
24
36
3.
4.
9
Rs1 - Design Stress Adjustment for Le/d
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
40
50
1.
2.
8-3/4
0.59
0.68
0.79
0.81
0.86
0.88
0.96
0.98
1.00
1.02
1.04
1.06
1.12
1.13
1.14
1.16
1.19
1.29
1.36
1.41
1.44
1.53
0.58
0.67
0.78
0.79
0.84
0.87
0.94
0.96
0.98
1.00
1.02
1.04
1.10
1.11
1.12
1.13
1.17
1.27
1.33
1.38
1.42
1.50
0.57
0.65
0.76
0.78
0.82
0.85
0.92
0.94
0.96
0.98
1.00
1.02
1.08
1.09
1.10
1.11
1.15
1.24
1.31
1.36
1.39
1.47
0.55
0.64
0.75
0.76
0.80
0.83
0.90
0.92
0.94
0.96
0.98
1.00
1.05
1.06
1.07
1.09
1.12
1.21
1.28
1.32
1.36
1.44
0.53
0.61
0.71
0.72
0.77
0.79
0.86
0.88
0.90
0.91
0.93
0.95
1.00
1.01
1.02
1.03
1.07
1.16
1.22
1.26
1.29
1.37
0.52
0.60
0.70
0.72
0.76
0.78
0.85
0.87
0.88
0.90
0.92
0.94
0.99
1.00
1.01
1.02
1.05
1.14
1.20
1.25
1.28
1.35
0.51
0.59
0.69
0.71
0.75
0.77
0.84
0.86
0.87
0.89
0.91
0.93
0.98
0.99
1.00
1.01
1.04
1.13
1.19
1.23
1.26
1.34
Design load ratios are calculated as the product of Rs1 and Rs2, but should not be taken as greater than 1.0. (Rs = [Rs1][Rs2] ≤ 1.0)
For the purposes of this table, the dimension d is measured in the direction normal to the axis about which buckling is considered. The designer should consider buckling about both axes and use the lesser design value. The
dimensions d and b are dressed, dry dimensions.
Tabulated values may be used for sawn lumber, structural glued laminated timber, or structural composite lumber where Emin'/Fc* ≥ 350.
Values of Rs1 and Rs2 may be interpolated for values of d, Le/d, and b other than those shown.
American Wood Council
8
DESIGN OF FIRE-RESISTIVE EXPOSED WOOD MEMBERS
Table 2B(1.5-hr)
Design Load Ratios, Rs = (Rs1)( Rs2) ≤ 1.0, for Compression Members Exposed on Four Sides1,2,3,4
1.5 – HOUR RATING (Structural Calculations at Standard Reference Conditions: CD=1.0, CM=1.0, Ct=1.0, Ci=1.0)
Depth of Member, d (measured in the direction normal to the axis about which buckling is considered)
6-3/4
6-7/8
7-1/4
7-1/2
8-1/4
8-1/2
8-3/4
9
9-1/4
Le/d
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
40
50
0.17
0.16
0.12
0.066
0.041
0.027
0.019
0.015
0.013
0.011
0.010
0.010
0.010
0.010
0.010
0.19
0.18
0.14
0.080
0.049
0.033
0.024
0.018
0.015
0.014
0.013
0.012
0.012
0.012
0.012
0.012
0.011
0.011
0.25
0.24
0.20
0.13
0.081
0.055
0.040
0.031
0.026
0.023
0.022
0.021
0.020
0.020
0.020
0.019
0.019
0.019
0.29
0.28
0.24
0.16
0.11
0.073
0.053
0.041
0.034
0.031
0.029
0.028
0.027
0.026
0.026
0.026
0.025
0.025
0.40
0.39
0.36
0.28
0.20
0.14
0.10
0.080
0.067
0.060
0.056
0.054
0.052
0.051
0.051
0.050
0.049
0.049
0.44
0.43
0.39
0.32
0.23
0.16
0.12
0.095
0.080
0.071
0.067
0.064
0.062
0.061
0.061
0.060
0.059
0.059
0.47
0.46
0.43
0.36
0.26
0.19
0.14
0.11
0.094
0.084
0.078
0.075
0.073
0.072
0.071
0.071
0.069
0.069
0.51
0.50
0.47
0.40
0.30
0.22
0.16
0.13
0.11
0.097
0.090
0.087
0.085
0.083
0.082
0.082
0.080
0.080
1.00
1.05
1.20
1.29
1.52
1.59
1.66
1.72
1.78
1.86
2.03
2.07
2.11
2.15
2.26
2.29
2.58
2.70
2.79
2.95
3.06
3.33
0.95
1.00
1.14
1.22
1.45
1.51
1.57
1.63
1.69
1.77
1.92
1.97
2.00
2.04
2.14
2.18
2.45
2.56
2.66
2.80
2.91
3.17
0.83
0.88
1.00
1.07
1.27
1.33
1.38
1.43
1.48
1.55
1.69
1.73
1.76
1.79
1.88
1.91
2.15
2.25
2.33
2.46
2.56
2.78
0.78
0.82
0.93
1.00
1.18
1.24
1.29
1.33
1.38
1.44
1.57
1.61
1.64
1.67
1.75
1.78
2.00
2.09
2.17
2.29
2.38
2.59
0.66
0.69
0.79
0.85
1.00
1.05
1.09
1.13
1.17
1.22
1.33
1.36
1.39
1.41
1.48
1.50
1.69
1.77
1.84
1.94
2.01
2.19
0.63
0.66
0.75
0.81
0.96
1.00
1.04
1.08
1.12
1.17
1.27
1.30
1.33
1.35
1.42
1.44
1.62
1.69
1.76
1.85
1.93
2.09
0.60
0.64
0.72
0.78
0.92
0.96
1.00
1.04
1.07
1.12
1.22
1.25
1.27
1.30
1.36
1.38
1.56
1.63
1.69
1.78
1.85
2.01
0.58
0.61
0.70
0.75
0.89
0.93
0.96
1.00
1.03
1.08
1.18
1.20
1.23
1.25
1.31
1.33
1.50
1.57
1.63
1.72
1.78
1.94
b
3.
4.
10-1/2
10-3/4
11
11-1/4
12
12-1/4
15
16-1/2
18
21
24
36
0.54
0.54
0.50
0.43
0.33
0.25
0.19
0.15
0.12
0.11
0.10
0.099
0.097
0.095
0.094
0.093
0.092
0.091
0.59
0.59
0.56
0.49
0.39
0.29
0.22
0.18
0.15
0.13
0.12
0.12
0.12
0.11
0.11
0.11
0.11
0.11
0.71
0.70
0.67
0.61
0.51
0.40
0.31
0.25
0.21
0.19
0.17
0.17
0.16
0.16
0.16
0.16
0.15
0.15
0.74
0.73
0.70
0.64
0.54
0.43
0.33
0.27
0.22
0.20
0.19
0.18
0.18
0.17
0.17
0.17
0.17
0.17
0.77
0.76
0.73
0.67
0.57
0.45
0.36
0.29
0.24
0.22
0.20
0.20
0.19
0.19
0.19
0.19
0.18
0.18
0.79
0.79
0.76
0.70
0.60
0.48
0.39
0.31
0.26
0.23
0.22
0.21
0.21
0.20
0.20
0.20
0.20
0.19
0.88
0.87
0.84
0.79
0.69
0.57
0.46
0.37
0.32
0.28
0.27
0.26
0.25
0.25
0.24
0.24
0.24
0.24
0.90
0.90
0.87
0.82
0.72
0.60
0.49
0.39
0.33
0.30
0.28
0.27
0.27
0.26
0.26
0.26
0.25
0.25
1.15
1.14
1.12
1.07
0.99
0.87
0.74
0.62
0.53
0.48
0.45
0.43
0.43
0.42
0.42
0.41
0.41
0.40
1.25
1.25
1.23
1.18
1.11
0.99
0.85
0.73
0.63
0.57
0.54
0.52
0.51
0.50
0.50
0.49
0.48
0.48
1.34
1.34
1.32
1.28
1.21
1.09
0.96
0.83
0.72
0.65
0.62
0.60
0.58
0.58
0.57
0.57
0.56
0.56
1.50
1.49
1.47
1.44
1.37
1.27
1.14
1.01
0.88
0.80
0.76
0.74
0.72
0.71
0.71
0.70
0.69
0.69
1.62
1.61
1.60
1.56
1.50
1.41
1.28
1.15
1.01
0.93
0.88
0.85
0.84
0.83
0.82
0.82
0.81
0.80
1.91
1.91
1.90
1.87
1.82
1.75
1.63
1.51
1.38
1.28
1.22
1.18
1.17
1.15
1.14
1.14
1.13
1.12
0.44
0.46
0.52
0.56
0.66
0.70
0.72
0.75
0.78
0.81
0.88
0.90
0.92
0.94
0.99
1.00
1.13
1.18
1.22
1.29
1.34
1.46
0.39
0.41
0.46
0.50
0.59
0.62
0.64
0.67
0.69
0.72
0.79
0.80
0.82
0.83
0.87
0.89
1.00
1.05
1.08
1.14
1.19
1.29
0.37
0.39
0.44
0.48
0.56
0.59
0.61
0.64
0.66
0.69
0.75
0.77
0.78
0.80
0.84
0.85
0.96
1.00
1.04
1.09
1.14
1.24
0.36
0.38
0.43
0.46
0.54
0.57
0.59
0.61
0.64
0.66
0.72
0.74
0.75
0.77
0.81
0.82
0.92
0.96
1.00
1.06
1.10
1.19
0.34
0.36
0.41
0.44
0.52
0.54
0.56
0.58
0.60
0.63
0.69
0.70
0.72
0.73
0.77
0.78
0.87
0.91
0.95
1.00
1.04
1.13
0.33
0.34
0.39
0.42
0.50
0.52
0.54
0.56
0.58
0.61
0.66
0.68
0.69
0.70
0.74
0.75
0.84
0.88
0.91
0.96
1.00
1.09
0.10
0.19
0.30
0.32
0.36
0.39
0.46
0.48
0.50
0.52
0.53
0.56
0.61
0.62
0.63
0.64
0.68
0.77
0.84
0.88
0.92
1.00
Rs2 - Design Stress Adjustment for Width, b, of Column
6-3/4
6-7/8
7-1/4
7-1/2
8-1/4
8-1/2
8-3/4
9
9-1/4
9-5/8
10-1/2
10-3/4
11
11-1/4
12
12-1/4
15
16-1/2
18
21
24
36
1.
2.
9-5/8
Rs1 - Design Stress Adjustment for Le/d
0.56
0.59
0.67
0.72
0.86
0.90
0.93
0.97
1.00
1.05
1.14
1.16
1.19
1.21
1.27
1.29
1.45
1.52
1.57
1.66
1.72
1.88
0.54
0.57
0.64
0.69
0.82
0.86
0.89
0.92
0.96
1.00
1.09
1.11
1.14
1.16
1.21
1.23
1.39
1.45
1.50
1.59
1.65
1.79
0.49
0.52
0.59
0.64
0.75
0.79
0.82
0.85
0.88
0.92
1.00
1.02
1.04
1.06
1.11
1.13
1.27
1.33
1.38
1.46
1.51
1.65
0.48
0.51
0.58
0.62
0.74
0.77
0.80
0.83
0.86
0.90
0.98
1.00
1.02
1.04
1.09
1.11
1.25
1.30
1.35
1.43
1.48
1.61
0.47
0.50
0.57
0.61
0.72
0.75
0.79
0.81
0.84
0.88
0.96
0.98
1.00
1.02
1.07
1.09
1.22
1.28
1.32
1.40
1.45
1.58
0.47
0.49
0.56
0.60
0.71
0.74
0.77
0.80
0.83
0.86
0.94
0.96
0.98
1.00
1.05
1.07
1.20
1.26
1.30
1.37
1.43
1.55
0.44
0.47
0.53
0.57
0.67
0.71
0.73
0.76
0.79
0.82
0.90
0.92
0.93
0.95
1.00
1.01
1.14
1.20
1.24
1.31
1.36
1.48
Design load ratios are calculated as the product of Rs1 and Rs2, but should not be taken as greater than 1.0. (Rs = [Rs1][Rs2] ≤ 1.0)
For the purposes of this table, the dimension d is measured in the direction normal to the axis about which buckling is considered. The designer should consider buckling about both axes and use the lesser design value. The
dimensions d and b are dressed, dry dimensions.
Tabulated values may be used for sawn lumber, structural glued laminated timber, or structural composite lumber where Emin'/Fc* ≥ 350.
Values of Rs1 and Rs2 may be interpolated for values of d, Le/d, and b other than those shown.
American Wood Council
DESIGN OF FIRE-RESISTIVE EXPOSED WOOD MEMBERS
Table 2C(2-hr)
9
Design Load Ratios, Rs = (Rs1)( Rs2) ≤ 1.0, for Compression Members Exposed on Four Sides1,2,3,4
2 – HOUR RATING (Structural Calculations at Standard Reference Conditions: CD=1.0, CM=1.0, Ct=1.0, Ci=1.0)
Depth of Member, d (measured in the direction normal to the axis about which buckling is considered)
8-1/4
8-1/2
8-3/4
9
9-1/4
9-5/8
10-1/2
10-3/4
Le/d
0.14
0.13
0.085
0.045
0.027
0.018
0.013
0.010
0.17
0.16
0.11
0.064
0.039
0.026
0.019
0.015
0.012
0.011
0.010
0.010
0.20
0.19
0.14
0.086
0.053
0.036
0.026
0.020
0.017
0.015
0.014
0.013
0.013
0.013
0.013
0.013
0.012
0.012
0.23
0.22
0.18
0.11
0.070
0.047
0.034
0.026
0.022
0.020
0.018
0.018
0.017
0.017
0.017
0.017
0.016
0.016
0.26
0.25
0.21
0.14
0.088
0.060
0.043
0.034
0.028
0.025
0.023
0.023
0.022
0.022
0.021
0.021
0.021
0.021
0.30
0.29
0.26
0.18
0.12
0.082
0.060
0.047
0.039
0.035
0.032
0.031
0.030
0.030
0.029
0.029
0.029
0.028
0.41
0.40
0.37
0.29
0.20
0.15
0.11
0.084
0.070
0.063
0.058
0.056
0.055
0.054
0.053
0.053
0.052
0.051
0.44
0.43
0.40
0.32
0.23
0.17
0.12
0.096
0.080
0.072
0.067
0.064
0.063
0.062
0.061
0.061
0.059
0.059
1.00
1.10
1.19
1.27
1.35
1.47
1.70
1.76
1.82
1.88
2.03
2.07
2.24
2.28
2.31
2.48
2.64
2.69
2.78
2.99
3.15
3.53
0.91
1.00
1.08
1.16
1.24
1.34
1.55
1.61
1.66
1.71
1.85
1.89
2.04
2.08
2.11
2.26
2.41
2.45
2.53
2.73
2.88
3.22
0.84
0.92
1.00
1.07
1.14
1.24
1.43
1.48
1.53
1.58
1.71
1.74
1.89
1.92
1.95
2.09
2.22
2.27
2.34
2.52
2.66
2.97
0.79
0.86
0.93
1.00
1.06
1.15
1.34
1.38
1.43
1.47
1.59
1.63
1.76
1.79
1.82
1.95
2.07
2.11
2.18
2.35
2.48
2.77
0.74
0.81
0.88
0.94
1.00
1.08
1.26
1.30
1.34
1.38
1.50
1.53
1.65
1.68
1.71
1.83
1.95
1.99
2.05
2.21
2.33
2.61
0.68
0.75
0.81
0.87
0.92
1.00
1.16
1.20
1.24
1.28
1.38
1.41
1.52
1.55
1.57
1.69
1.80
1.83
1.89
2.04
2.15
2.40
0.59
0.64
0.70
0.75
0.80
0.86
1.00
1.04
1.07
1.10
1.19
1.22
1.31
1.34
1.36
1.45
1.55
1.58
1.63
1.76
1.85
2.07
0.57
0.62
0.67
0.72
0.77
0.83
0.97
1.00
1.03
1.06
1.15
1.17
1.27
1.29
1.31
1.40
1.50
1.53
1.58
1.70
1.79
2.00
b
12
12-1/4
13-1/4
13-1/2
13-3/4
15
16-1/2
17
18
21
24
36
0.47
0.46
0.43
0.35
0.26
0.19
0.14
0.11
0.091
0.082
0.076
0.073
0.071
0.070
0.069
0.069
0.068
0.067
0.49
0.49
0.45
0.38
0.28
0.21
0.16
0.12
0.10
0.092
0.086
0.082
0.080
0.079
0.078
0.078
0.076
0.075
0.58
0.57
0.54
0.47
0.37
0.28
0.21
0.17
0.14
0.12
0.12
0.11
0.11
0.11
0.11
0.11
0.10
0.10
0.60
0.60
0.57
0.50
0.40
0.30
0.23
0.18
0.15
0.14
0.13
0.12
0.12
0.12
0.12
0.12
0.11
0.11
0.70
0.70
0.67
0.61
0.50
0.39
0.31
0.24
0.21
0.18
0.17
0.17
0.16
0.16
0.16
0.16
0.15
0.15
0.73
0.72
0.69
0.63
0.53
0.42
0.33
0.26
0.22
0.20
0.18
0.18
0.17
0.17
0.17
0.17
0.16
0.16
0.75
0.75
0.72
0.66
0.56
0.44
0.35
0.28
0.23
0.21
0.20
0.19
0.19
0.18
0.18
0.18
0.18
0.17
0.86
0.86
0.83
0.78
0.68
0.56
0.45
0.36
0.31
0.28
0.26
0.25
0.24
0.24
0.24
0.24
0.23
0.23
0.98
0.97
0.95
0.90
0.81
0.68
0.56
0.46
0.39
0.35
0.33
0.32
0.31
0.31
0.31
0.30
0.30
0.30
1.02
1.01
0.99
0.94
0.85
0.72
0.60
0.50
0.42
0.38
0.36
0.34
0.34
0.33
0.33
0.33
0.32
0.32
1.09
1.08
1.06
1.01
0.92
0.80
0.67
0.56
0.48
0.43
0.41
0.39
0.38
0.38
0.37
0.37
0.36
0.36
1.26
1.25
1.23
1.19
1.12
1.00
0.86
0.74
0.64
0.58
0.54
0.52
0.51
0.51
0.50
0.50
0.49
0.49
1.40
1.39
1.38
1.34
1.27
1.16
1.02
0.89
0.78
0.71
0.67
0.64
0.63
0.62
0.62
0.61
0.61
0.60
1.75
1.75
1.73
1.70
1.65
1.56
1.44
1.31
1.18
1.08
1.03
1.00
0.98
0.97
0.96
0.96
0.95
0.94
0.40
0.44
0.48
0.51
0.55
0.59
0.69
0.71
0.73
0.76
0.82
0.84
0.90
0.92
0.93
1.00
1.07
1.09
1.12
1.21
1.27
1.43
0.38
0.42
0.45
0.48
0.51
0.56
0.64
0.67
0.69
0.71
0.77
0.78
0.85
0.86
0.88
0.94
1.00
1.02
1.05
1.13
1.19
1.34
0.37
0.41
0.44
0.47
0.50
0.55
0.63
0.66
0.68
0.70
0.75
0.77
0.83
0.85
0.86
0.92
0.98
1.00
1.03
1.11
1.17
1.31
0.36
0.39
0.43
0.46
0.49
0.53
0.61
0.63
0.66
0.68
0.73
0.75
0.81
0.82
0.83
0.89
0.95
0.97
1.00
1.08
1.14
1.27
0.33
0.37
0.40
0.43
0.45
0.49
0.57
0.59
0.61
0.63
0.68
0.69
0.75
0.76
0.77
0.83
0.88
0.90
0.93
1.00
1.05
1.18
0.32
0.35
0.38
0.40
0.43
0.47
0.54
0.56
0.58
0.59
0.64
0.66
0.71
0.72
0.73
0.79
0.84
0.85
0.88
0.95
1.00
1.12
0.28
0.31
0.34
0.36
0.38
0.42
0.48
0.50
0.52
0.53
0.57
0.59
0.63
0.64
0.66
0.70
0.75
0.76
0.79
0.85
0.89
1.00
Rs2 - Design Stress Adjustment for Width, b, of Column
8-1/4
8-1/2
8-3/4
9
9-1/4
9-5/8
10-1/2
10-3/4
11
11-1/4
12
12-1/4
13-1/4
13-1/2
13-3/4
15
16-1/2
17
18
21
24
36
3.
4.
11-1/4
Rs1 - Design Stress Adjustment for Le/d
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
40
50
1.
2.
11
0.55
0.60
0.65
0.70
0.74
0.81
0.94
0.97
1.00
1.03
1.11
1.14
1.23
1.25
1.27
1.36
1.45
1.48
1.53
1.64
1.73
1.94
0.53
0.58
0.63
0.68
0.72
0.78
0.91
0.94
0.97
1.00
1.08
1.10
1.19
1.21
1.23
1.32
1.41
1.43
1.48
1.60
1.68
1.88
0.49
0.54
0.59
0.63
0.67
0.73
0.84
0.87
0.90
0.93
1.00
1.02
1.11
1.12
1.14
1.22
1.30
1.33
1.37
1.48
1.56
1.74
0.48
0.53
0.57
0.61
0.65
0.71
0.82
0.85
0.88
0.91
0.98
1.00
1.08
1.10
1.12
1.20
1.27
1.30
1.34
1.44
1.52
1.70
0.45
0.49
0.53
0.57
0.61
0.66
0.76
0.79
0.81
0.84
0.90
0.93
1.00
1.02
1.03
1.11
1.18
1.20
1.24
1.34
1.41
1.58
0.44
0.48
0.52
0.56
0.60
0.65
0.75
0.77
0.80
0.82
0.89
0.91
0.98
1.00
1.02
1.09
1.16
1.18
1.22
1.31
1.39
1.55
0.43
0.47
0.51
0.55
0.59
0.64
0.74
0.76
0.79
0.81
0.88
0.90
0.97
0.98
1.00
1.07
1.14
1.16
1.20
1.29
1.36
1.53
Design load ratios are calculated as the product of Rs1 and Rs2, but should not be taken as greater than 1.0. (Rs = [Rs1][Rs2] ≤ 1.0)
For the purposes of this table, the dimension d is measured in the direction normal to the axis about which buckling is considered. The designer should consider buckling about both axes and use the lesser design value. The
dimensions d and b are dry dressed dimensions.
Tabulated values may be used for sawn lumber, structural glued laminated timber, or structural composite lumber where Emin'/Fc* ≥ 350.
Values of Rs1 and Rs2 may be interpolated for values of d, Le/d, and b other than those shown.
American Wood Council
10
DESIGN OF FIRE-RESISTIVE EXPOSED WOOD MEMBERS
Timber Decks
Design load ratios, Rs, for fire design of timber
decks are given in Tables 3.1 and 3.2. The Rs values
given in Table 3.1 are applicable to butt-joint timber
decking fully exposed on one face and partially exposed on the sides, in accordance with NDS Section
16.2.5. The Rs values given in Table 3.2 are applicable
to double and single tongue-and-groove decking exposed only on one face. These calculation procedures
do not address thermal separation.
Where:
Rs = Design load ratio (see Tables 3.1 and 3.2)
M = ASD design moment per foot of deck width
(in.-lbs/ft)
Fb' = Adjusted ASD bending design value used
in structural calculations (psi)
S = Section modulus of uncharred deck per
foot of deck width (in.3/ft)
For fire design, the following condition must be satisfied:
Table 3.1
Design Load Ratios, Rs, for Butt-Jointed Timber Decks
(Protected on Top Face; Partially Protected on Sides per NDS Section 16.2.5)
(Structural Calculations at Standard Reference Conditions: CD=1.0, CM=1.0, Ct=1.0, Ci=1.0, CL=1.0)
1-HOUR
Width, b
1-1/2
2-1/2
5-1/2
2-1/2
2-1/2
0.05
0.12
0.15
0.18
3
0.10
0.24
0.30
0.36
0.03
3-1/2
0.14
0.35
0.44
0.53
0.08
4
0.18
0.45
0.57
0.68
0.14
4-1/2
0.21
0.54
0.68
0.80
0.19
5
0.24
0.61
0.77
0.92
0.24
5-1/2
0.27
0.68
0.85
1.00
0.29
Design load ratios (Rs) may be interpolated for widths (b) and depths (d) other than those shown.
Table 3.2
3-1/2
2-HOUR
5-1/2
3-1/2
5-1/2
0.05
0.16
0.28
0.39
0.50
0.59
0.05
0.10
0.16
0.21
0.08
0.16
0.24
0.32
Design Load Ratio, Rs
Depth, d
1.
1.5-HOUR
3-1/2
0.04
0.12
0.21
0.30
0.38
0.45
Design Load Ratios, Rs, for Tongue-and-Groove Timber Decks
(Protected on Top Face and Sides per NDS Section 16.2.5)
(Structural Calculations at Standard Reference Conditions: CD=1.0, CM=1.0, Ct=1.0, Ci=1.0, CL=1.0)
1-HOUR
Depth, d
1.
1.5-HOUR
Design Load Ratio, Rs
2-1/2
0.22
3
0.46
3-1/2
0.67
4
0.86
4-1/2
1.00
5
1.00
5-1/2
1.00
Design load ratios (Rs) may be interpolated for depths (d) other than those shown.
0.08
0.23
0.40
0.56
0.71
0.85
American Wood Council
2-HOUR
0.03
0.12
0.25
0.38
0.51
DESIGN OF FIRE-RESISTIVE EXPOSED WOOD MEMBERS
Connections
Figure 3
Where a specified fire resistance rating is required,
Section 16.3 of the NDS requires connectors and fasteners to be protected from fire exposure. This protection can be achieved by any of the following:
 Wood members having dimensions sufficient
to prevent the char front (at a depth of
achar /1.2) from reaching the connectors and
fasteners for the duration of the required fire
resistance rating time (see example details in
Figures 3, 4 and 5),
 Fire-rated gypsum board having a finish rating greater than or equal to the required fire
resistance rating (see example details in Figure 6), or
 Any approved coating having a fire rating
greater than or equal to the required fire resistance rating time (see detail in Figure 7).
Beam to Column Connection
Connection Exposed to Fire Where Appearance is a Factor
Figure 4
Application
Allowable loads on beams and columns are determined using design procedures from the NDS.
For glued laminated timber members given in
NDS Supplement Tables 5A and 5C that are rated for
1-hour fire resistance, an outer tension lamination shall
be substituted for a core lamination on the tension side
(typically the bottom) for unbalanced beams, and on
both top and bottom for balanced beams. For glued
laminated timber members that are rated for 1.5- or 2hour fire resistance, two outer tension laminations
shall be substituted for two core laminations on the
tension side (typically the bottom) for unbalanced
beams, and on both top and bottom for balanced
beams.
The procedure described in this brochure is intended to assist the designer of wood framed structures
in achieving predictable performance within specified
fire resistance requirements. Special effort has been
made to assure that the information reflects the state of
the art. However, the American Wood Council does
not assume responsibility for particular designs or calculations prepared from this publication.
American Wood Council
Beam to Girder – Concealed
Connection
11
12
Figure 5
DESIGN OF FIRE-RESISTIVE EXPOSED WOOD MEMBERS
Column Connections – Covered
Figure 7
Beam to Column Connection
Connection Exposed to Fire Where Appearance is Not a Factor
Figure 6
Beam to Column Connection
Connection Not Exposed to Fire
For additional information contact:
American Wood Council
222 Catoctin Circle, SE, Suite 201
Leesburg, VA 20175
http://www.awc.org
202-463-2766
Copyright © 2014 American Wood Council
American Wood Council