Temperature Factor Explained:
Wood that is expected to be exposed to high temperatures for long periods of time will need to take a temperature factor into account when designed.
Note: For temperatures below 100º Fahrenheit, you can take Ct to be equal to unity (1.0).
Temperature Factor Table:
The following temperature factors can be used for sawn lumber, glued laminated timber , prefabricated I-joists, structural composite lumber, and wood structural panels.
| Table 1: Temperature Factor (Ct) | ||||
| Reference Design Values | Moisture Condtions | Ct | ||
| T ≤ (100ºF) | (100ºF ≤ T ≤ 125ºF) | (125ºF ≤ T ≤ 150ºF) | ||
| Ft, E, Emin | Wet or Dry | 1.0 | 0.9 | 0.9 |
| Fb, Fv, Fc, Fc-p | Dry | 1.0 | 0.8 | 0.7 |
| Wet | 1.0 | 0.7 | 0.5 | |
where:
Fb = Bending Stress
Ft = Tension Stress
Fv = Shear Stress
Fc-p = Compression Stress Perpindicular to the grain
Fc = Compression Stress Parallel to the grain
E = Modulus of Elasticity [2]
Ft = Tension Stress
Fv = Shear Stress
Fc-p = Compression Stress Perpindicular to the grain
Fc = Compression Stress Parallel to the grain
E = Modulus of Elasticity [2]
Emin = Minimum Modulus of Elasticity [2]
References:
- American Forest and Paper Association, "National Design Specification for Wood Construction", 2005