Research on the improvement of test methods for the determination of dust penetration in enclosures of equipment intended for explosive atmospheres

Abstract

Carcasses of electrical or non-electrical equipment operating in potentially explosive atmospheres must provide a certain degree of protection against access to hazardous parts, penetration of solid bodies and/or water penetration, which must be tested according to the specifications of the Ex protection types. Normal protection classes are indicated by the international IP code followed by two characteristic digits referring to the protection against penetration of solid foreign bodies and water protection, followed by optional letters if required by the beneficiary according to the imposed conditions of use. Within the ENExEMEIP laboratory, have been developed laboratory tests to verify the first characteristic figure of the standard degree of protection according to the standardized European method. In the paper is presented the test stand of the large gauge equipment, a stand made with state-of-the-art equipment that provides the necessary performance for the accreditation of the test according to the standardized requirements. Checking dustproof protection to equipment used in areas where explosive atmospheres generated by combustion dust may occur is particularly important for assessing compliance with the requirements of the ATEX Directive [5], as this protection is a basic requirement for explosion protection.

Considerations regarding test methods against dust and water ingress protection for Ex equipment

“…According to Directive 2014/34 / EU, technical equipment intended for use in potentially explosive atmospheres is divided into two groups (group I: mining and group II: gases, vapours, mists, flammable liquids and combustible dusts) and three categories: 3G / 3D, 2G / 2D, 1G / 1D depending on the level of protection required for safe use in the area to be used [1], [2]. According to harmonized standards, technical equipment intended for use in potentially explosive atmospheres is divided into three groups (group I: mining, group II: gases, vapours, mists, flammable liquids and group III: combustible dusts) and three categories depending on the required level of protection: Gc / Dc, Gb / Db, Ga / Da.…”

Quality assurance issues for normal grade testing protection provided by equipment housings Ex

“…Schematically, Table 1 presents the relationship that must exist between the hazardous atmosphere area and the level of protection required for the equipment (component), so that [2,4,5]. Therefore, in order to reduce the risk of an explosion in areas with potentially explosive atmospheres generically called "Ex zones", special construction equipment (with an appropriate type of protection) should be used that does not produce electrical sparks, arcs, mechanical sparks (impact and friction), static electricity, overheated surfaces, or other energy sources that could initiate the atmosphere and generate an explosion.…”