2. Find Information Home Kiln theory Basic theory Kiln schedules based on drying gradient

Since 1920, Universities in Europe and the United States have been making suggested drying schedules on different species and thicknesses. There are three general types of drying schedules available:

North American:
Is based on constant fan operation and Wet/Dry bulb temperatures. These can easily be converted into a Temp/RH% schedule for those kiln controllers which use an RH sensor instead of a wet bulb.
These schedules have numbers like T4-E6, T2-C1, etc.

British:
These schedules are also based on a Wet/Dry bulb temperatures and can be used the same way as North American schedules.

Drying gradient:
The species are normally divided into 4 groups depending on the drying characteristic. Each group and thickness is then given a maximum drying gradient that one can use and still expect a high quality drying.
The temperature will depend on the specie you are drying. Generally the slower and harder the specie dries, the lower the initial temperature is.

There is much good literature available on drying lumber; but you can also find some which is less clear and sometimes has questionable accuracy. When you are studying the subject always use your common sense and try to compare it to your own experience.

We hope this information meets with your expectation and approval. We always welcome your opinions and suggestions. Feel free to email us at techsupport@kiln-direct.com.