The paper will present results of hydrogen/oxygen mixtures ignited by using electric sparks, electrostatic discharges, a heating element and a flame. Measurements of the lower flammability limit (LFL) was done for each ignition method. The hydrogen mixtures of different concentrations were ignited at the bottom of a combustion chamber, leading to an upward propagation of the resulting flame. At some level of concentration the combustion was partial due to the limited upward propagation. The complete combustion of the whole mixture was observed at concentration limits higher than the known LFL of 4%2vol. for hydrogen in air. The paper will describe the test facilities and the resulting ignition probabilities for different ignition methods.