This work determines the thermal characteristics of a variety of biomass/wastes suitable for gasification or combustion as a method of disposal. These characteristics act as indicators to the performance in full-scale plant. The work was carried out in a pot furnace burning each waste individually under both normal combustion (primary air flowrate, 1250 kg/h/m[sup 2]) and sub-stoichiometric/gasification (primary air flowrate, 150 kg/h/m[sup 2]) conditions. The wastes tested were refuse derived fuel (RDF), digested sewage sludge, wood, straw and scrap tyres. Thermal characteristics cover the fuel bed temperature, the rates of combustion/ignition, the ignition temperature, thermal loading, potential clinker formation and product gas composition.