Explosion relief venting is a commonly used form of explosion protection, employed in a wide range of industries, to protect vessels and production units from the overpressures generated by dust or gas explosions. As well as the pressure developed inside a vented vessel, a vented explosion generates secondary effects, due to blast and fire, outside the vented vessel. These secondary effects need to be considered so that appropriate protection can be provided for people or nearby installations and buildings. This report seeks to provide some practical guidance on the external effects of vented dust explosions. The guidance is based on the results of explosion studies undertaken across Europe, in particular the foundational work of Battelle and Christen Michelson Research, together with further studies which formed part of the CEC sponsored CREDIT project. 20 pages.