Jet flames are commonly used as flame effects in pyrotechnical shows, and are also a possible risk in industries that uses pressurised flammable gas. For these users it is important to  make fire safety engineering calculations to minimise the risks. This project focus on jet flames that are used in pyrotechnic shows where, e.g. it is important to determine the safety distance to the audience. Up to now most studies made concerning jet flames regards jet flames in subsonic regiments, whilst there is a lack of studies concerning sonic jet flames and mathematical formulations for radiation from these cases are limited. This makes pre-determination of temperatures, safety distances, flame heights etc. a challenge. Based on information found, and assumptions when needed, calculations of the safety distance were made.