Definition

The equilibrium moisture content \(EMC\) is "the moisture content [%] of a fuel particle allowed sufficient time to reach equilibrium with its environment, i.e. no net moisture exchange" (Bradshaw et al. 1983).

Formula

Simard (1968) defined the \(EMC\) as follows:

\[ EMC= \begin{cases} 0.03229+0.281073\cdot{H}-0.000578\cdot{H}\cdot{T}, & \mbox{for }H<10\% \\ &\\ 2.22749+0.160107\cdot{H}-0.01478\cdot{T}, & \mbox{for }10\%\leqslant{H}<{50}\% \\ &\\ 21.0606+0.005565\cdot{H^2}-0.00035\cdot{H}\cdot{T}-0.483199\cdot{H}, & \mbox{for }H\geqslant50\% \end{cases} \]

where \(H\) is relative air humidity [%] and \(T \)air temperature [°F].

References

Literature:
Simard (1968)
Bradshaw et al. (1983)