Dry Kiln Operator's Manual

The purpose of this manual is to describe both the basic
and practical aspects of kiln drying lumber. The
manual is intended for several types of audiences.
First and foremost, it is a practical guide for the kiln
operator-a reference manual to turn to when questions
arise. It is also intended for mill managers, so that they
can see the importance and complexity of lumber drying
and thus be able to offer kiln operators the support
they need to do their job well. Finally, the manual is
intended as a classroom text-either for a short course
on lumber drying or for the wood technology curriculum
in universities or technical colleges.

This manual is a revision of the 1961 edition by
Edmund F. Rasmussen. Forest Service staff who
contributed to that original edition were Raymond C.
Rietz, Edward C. Peck, John M. McMillen, Harvey H.
Smith, and A.C. Knauss. It is a credit to these men
that the 1961 edition has been in wide use and demand
for the past 28 years. It is also to their credit that even
though the manual is out of date in many parts, we
were able to use the basic framework of the original
edition to build on.

The Forest Products Laboratory staff involved in this
revision were William T. Simpson (who wrote the introduction
and had overall responsibility for coordination),
R. Sidney Boone, James C. Ward, and John L. Tschernitz.
Each person was responsible for revising certain
chapters or parts of chapters. This assignment of responsibilities
is indicated on the chapter-opening pages.
Chapters 5 and 7 of the original manual were combined
in this revision. Chapter 11, Energy in Kiln Drying,
is a new chapter and was written by John L. Tschernitz.
In addition to this assignment of chapters, there
were many formal and informal meetings among us to
exchange ideas.

Many people helped in the revision. We visited many
mills to make sure we understood current and developing
kiln-drying technology as practiced in industry, and
we thank all the people who allowed us to visit. Professor
John L. Hill of the University of New Hampshire
provided the background for the section of chapter 6
on the statistical basis for kiln samples. Kiln manufacturers
were also very helpful in spending time with us
and providing photographs and schematics of drying
equipment. In particular, we wish to thank Coe Manufacturing
Company, Hemco (Harvey Engineering and
Manufacturing Corp.), Irvington–Moore, Nyle Corporation,
Uraken Canada, Ltd., and Wagner Electronic
Products, Inc., for their help. We also thank Professor
Charles J. Kozlik, retired from Oregon State University,
for arranging and accompanying several of us on a
plant tour in the Northwest.