Ignition of flammable atmospheres by mechanical stimuli

As readers of HazardEx will be well aware, following the introduction of the ATEX 95 and 137 directives, there are now requirements on both manufacturers of equipment and employers to consider the likelihood of ignition flammable atmospheres from mechanical impacts/sliding. The aim of this article is not to review legislative requirements, as these are well discussed else where, but to provide insight into the ignition mechanism and relevant research literature to assist those needing to make such assessments. It is certainly not the intention to advocate ignition source control as an appropriate hazard management strategy , particularly with easily ignited gases like hydrogen- this needs to be decided on a case by case basis. Guidance in the design standards i.e. [1] has improved from earlier versions, but still does not convey very well the likely influence of parameters such as material hardness, load, velocities and impact angle.