The "ignition temperature" of wood is reported for piloted ignition of a wood surface being exposed to a thermal radiant flux. This is not the same as the ignition temperature due to self-heating, which is not a single value, but must be reported with respect to a critical dimension or characteristic length. Wood will ignite at "room temperature, if the critical length is achieved. The smaller the "pile size" the higher the critical temperature. The opposite is also true.

"All the results were that low temperature long-term exposure can cause ignition of wood below it reported ignition temperature." This is currently true for a range of temperatures on the order of 150 degrees C depending on the critical length for the material. This is not currently a reliable determination for temperatures on the order of 77 to 100 degrees C for dimensional lumber.

Douglas J. Carpenter, MScFPE, CFEI, PE, FSFPE
Vice President & Principal Engineer
Combustion Science & Engineering, Inc.
8940 Old Annapolis Road, Suite L
Columbia, MD 21045
(410) 884-3266
(410) 884-3267 (fax)
www.csefire.com