NON-ELECTRICAL EQUIPMENT FOR POTENTIALLY EXPLOSIVE ATMOSPHERES 

Abstract - The introduction of Directive 94/9/EC in Europe marked the first full-coverage analysis of all possible ignition sources. Against the background of the well-known standards for electrical equipment, an additional series of standards EN 13463-x was hurriedly created that takes the new aspects into account while relying on the successful application of existing types of protection. In nearly all cases, the equipment contains both electrical and non-electrical ignition sources. According to the European directive, all of the iginition sources have to be eliminated. The article takes the inspection lamp for Zone 0 as example. Apart from the electrical part (flameproof enclosure), the inspection lamp also has a non-electrical part. Ignition sources in the non-electrical part, such as hot surfaces, mechanical sparking, static electricity and optical radiation, are dealt with in the article. The most important of these new standards is EN 13463-1 “Non-electrical equipment for potentially explosive atmospheres, Part 1: Basic method and requirements”. This standard describes the process of ignition hazard assessment. The first step in the process is the analysis of all possible ignition sources in line with the directive without any attempt to anticipate possible solutions. The frequency with which individual hazards occur is determined in a second step. Distinctions are made between ignition hazards occurring during normal operation, during expected malfunctions, or only as a result of rare malfunctions. Depending on the equipment category sought (category 1, 2 or 3), rare or frequently occurring malfunctions or perhaps only those occurring during normal operation are covered. This risk analysis has a direct effect on the action to be taken. Besides additional tests, verifications and/or material certifications, a given condition can also be excluded or sharply reduced with the instruction manual. The importance of the instruction manual is increased substantially in this area. A salient function of the instruction manual is to specify the use for which the equipment in question was designed, i.e. the manufacturer is obligated to pin down clearly the limiting conditions for the use of its equipment. The presentation explains the relevant concepts and the ignition hazard assessment using examples for the different categories.