Experiments on flammability limits, ignition energies, and flame speeds were carried out in a 11.25- and a 400-liter combustion vessel at initial pressures and temperatures of 100 kPa and 295 K, respectively. Flammability maps of hydrogen-nitrous oxide-nitrogen, methane-nitrous oxide-nitrogen, ammonia-nitrous oxide-nitrogen, and ammonia-nitrous oxide-air, as well as lean flammability limits of various hydrogen-methane-ammonia-nitrous oxide-oxygen-nitrogen mixtures were determined. ignition energy bounds of methane-nitrous oxide, ammonia-nitrous oxide, and ammonia-nitrous oxide-nitrogen mixtures have been determined and the influence of small amounts of oxygen on the flammability of methane-nitrous oxide-nitrogen mixtures has been investigated. Flame speeds have been measured and laminar burning velocities have been determined for ammonia-air-nitrous oxide and various hydrogen-methane-ammonia-nitrous oxide-oxygen-nitrogen mixtures. Lower and upper flammability limits (mixing fan on, turbulent conditions) for ignition energies of 8 J are: H-2-N2O: 4.5 similar to 5.0% H-2(LFL), 76 similar to 80% H-2(UFL); CH4-N2O: 2.5 similar to 3.0% CH4(LFL), 43 similar to 50% CH4(UFL); NH3-N2O: 5.0 similar to 5.2% NH3(LFL), 67.5 similar to 68% NH3(UFL). Inerting concentrations are: H-2-N2O-N-2: 76% N-2; CH4-N2O-N-2: 70.5% N-2; NH3-N2O-N-2: 61% N-2; NH3-N2O-air: 85% air. Flammability limits of methane-nitrous oxide-nitrogen mixtures show no pronounced dependence on small amounts of oxygen (<5%). Generally speaking, flammable gases with large initial amounts of nitrous oxide or ammonia show a strong dependence of flammability limits on ignition energy.