The blast wave from the detonation of a cylindrical charge of silver azide with a charge mass varying between 10 mg and 0.5 mg is described based on experimental results of pressure measurements and visualizations. Primary shock wave, secondary shock wave, and detonation products are seen on sequences of photos taken with an image converter camera. From these pictures x - t diagrams could be established and based on these x - t data, the over pressure could be obtained as a function of distance. Comparing the obtained face - on over pressure data with TNT reference data against scaled distance, the blast waves generated by the investigated charges were seen to follow the cube - root scaling law. Furthermore an average TNT equivalence factor of silver azide was found to be approximately 0.45.