A PARALLEL BETWEEN THE TYPES OF PROTECTION FLAMEPROOF ENCLOSURE �d� AND INCREASED SAFETY �e� IN THE CONTEXT OF HYDROGEN EXPLOSIVE ATMOSPHERES

Abstract

A type of protection represents specific measures applied to equipment to avoid ignition of a surrounding explosive atmosphere. Flameproof enclosure �d� consists in placing the parts that could ignite an explosive atmosphere inside of an enclosure that can withstand the pressure developed during an internal explosion of an explosive mixture and which prevents the explosion transmission to the explosive atmosphere surrounding the enclosure. Increased safety �e� represents a type of protection that consists in applying additional measures to give increased security against the possibility of excessive temperatures and against the occurrence of arcs and sparks. The purpose of the paper is to consider some specific issues related to the design of an explosion-proof equipment (to choose the adequate type of protection flameproof enclosure or increased safety when these can be applied for the same equipment) and selection of the proper equipment and type of protection in the design phase of an installation, because sometimes, in practice, the designer of an installation must indicate the equipment parameters (including the type of protection). The method to address the identified issues is to analyze and compare some specific requirements of the two types of protection (level of protection, tests in explosive mixtures, group classification, applicability to equipment and maximum surface temperature), considering also the hydrogen-air explosive atmospheres.