A method for the determination of safety properties for micro reactors and micro structured components is presented. Micro structured reactors are not inherently safe but the range of safe operating conditions of micro reactors are extended since the explosion region is reduced. The lambda/3 rule was demonstrated to be applicable to micro scale tubes for stoichiometric mixtures of ethane-oxygen and ethane-nitrous oxide. Furthermore first results from an investigation concerning detonation propagation through a micro reactor of non-ideal geometry are shown. Initial pressure investigated is ranging from low pressure up to 100 kPa. (C) 2011 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.