An experimental investigation of an influence of trifluoromethane CHF3, pentafluoroethane C2HF5 and perfluorobutane C4F10 on near-limit hydrogen-nitrous oxide and methane-nitrous oxide premixed flames was performed. Flammability limits, a maximum explosion pressure Delta P-max, maximum rate of pressure rise (dP/dt)(max), and a laminar burning velocity S-u were determined. The flammability area in the case of N2O as an oxidizer is substantially wider than for the case of the oxidizer which is the mixture of oxygen and nitrogen with the O-2 content 25% (vol.). The dependences of S-u. Delta P-max and (dP/dt)(max) on concentration of the fluorinated hydrocarbons are characterizing by an availability of maxima which positions are close to the peak concentrations of the flammability regions. A qualitative interpretation of the results obtained is given. (C) 2013 Elsevier Ltd. All rights reserved.