INTRODUCTION IEC/IEEE 60079-30-1 is intended to provide a comprehensive overview of the essential requirements and testing appropriate to electric surface heating equipment used in explosive atmospheres. The requirements of this part of IEC 60079 are considered to be the minimum requirements for equipment protection levels Gb@ Gc@ Db@ and Dc in explosive atmospheres for gases@ dusts@ and fibres/flyings. While some of this work already exists in national standards or international standards@ this standard has collated much of this existing work and considerably added to it. This standard also contains the minimum requirements for users applying the Division method of area classification.