Time needed under specified conditions for a fuel particle to lose about 63 percent of the difference between its initial moisture content and its equilibrium moisture content. If conditions remain unchanged, a fuel will reach 95 percent of its equilibrium moisture content after four timelag periods.

The drying time, under specified conditions, required for a dead fuel to loose about 63 percent of the difference between its initial moisture content and its Equilibrum Moisture Content. Providing conditions remain unchanged, a fuel will reach 95 percent of its EMC after four timelag periods.

the drying time, under stated conditions of dry-bulb temperature, relative humidity, wind speed, and time of the year, required for dead fuels to lose about two-thirds (2/3) of the difference between their initial moisture content and their equilibrium moisture content. The TL therefore represents the rate of moisture change in a fuel. Dead forest fuels can have TL values from minutes to months. The fuels represented by the Fine Fuel Moisture Code, Duff Moisture Code, and Drought Code in the Canadian Forest Fire Weather Index System have TL values of 2/3 (or 16 hours), 12, and 52 days in average weather, respectively.