Heat Treating Wood for Export
The objective of Heat Treating is to exterminate any and all living organisms in the wood. This Heat Treat process also eliminates any organisms inside the lumber that you can’t see . . . Lumber used to construct crates and pallets must also be thoroughly heated treated.
A Heat Treat chamber related to the wood packaging industry is essentially an oven for the specific treatment of the wood for ISPM-15 compliance. Temperature sensors (known as thermocouples) connected to a recording device are placed in strategic locations within the wood material in the chamber. Gauges outside the chamber insure the core temperature of the wood reaches a required minimum of 133 degrees Fahrenheit (56 Celsius) for 30 minutes. Once that core temperature is attained, no living organisms can survive. The moisture in the wood has been driven to the surface resulting in a moisture content reduced to 19% or less. Research has concluded that at 19% content there isn’t enough moisture for an organism to live on. A kiln can serve the same capacity when specifically calibrated to reach the temperature and time frame specified by the ISPM-15 standards.
Kiln Dried – Heat Treated
The purpose of Kiln-Dried lumber (KD as seen on lumber grade stamps) is to reduce the moisture content of the wood (19% or less). This is a means to control warping, fungal growth and other quality features. The kilns or “ovens” the lumber is placed into, don’t necessarily reach the sustained temperature of 133 degrees Fahrenheit (56 Celsius) for 30 minutes that would qualify as Heat Treated. Many lumber mills today are processing their lumber to meet the Heat Treat requirements of ISPM-15 and you will see a lumber grade stamp of KD-HT.