A. N. Subbotin UDC 536.24:533.6 The laws governing propagation of peat fire under varying outer conditions and different moisture contents are studied. Critical values of moisture content and the conditions of heat and mass exchange of a peat bed and the surrounding medium under which combustion can stop are determined based on numerical calculations. It is found that under certain conditions the combustion wave propagates along the peat bed even in the absence of air influx from the outer medium. The assumption that in small losses of heat to the outer medium the combustion wave will propagate along the bed surface and in intense heat transfer it will move into the depth of the bed is confirmed. It is shown that in combustion of a thick bed of peat layer-by-layer combustion may take place. Tomsk State University, 36 Lenin Ave., Tomsk, 634059, Russia; email: fire@fire.tsu.tomsk.su. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 76, No. 5, pp. 159-165, September-October, 2003. Original article submitted January 14, 2003.