The Umpqua Biochar Education Team developed flame cap kilns for an NRCS Conservation Innovation Grant. This guideline gives shop drawings for several types of flame cap kilns to produce biochar from woody debris. The drawings were produced by students in the Umpqua Community College Welding Department.

Information on the Ring of Fire biochar kiln here.  Note: The RoF is not open source kiln design and is registered IP of Wilson Biochar LLC.