When we speak about an electrical installation in an area with presence of explosive atmosphere, we have to distinguish different...
When we speak about an electrical installation in an area with presence of explosive atmosphere, we have to distinguish different responsibilities attributed to various actors with different skills. The main difference is between the responsibility on the equipment and the liability on the electrical system.
The various actors involved are:
The safety level of the equipment must be guaranteed by the manufacturer which certifies its eligibility for installation in certain areas, through the documentation required by the ATEX Directive 94/9/EC.
The documents that must always go with an equipment are:
The manual of use and maintenance is of the utmost importance because its rules must be followed by the installer to ensure the essential safety requirements of the equipment.
The instructions must include:
The designer is responsible for the proper selection of the components, on the basis of system requirements, areas of use and environmental conditions. The choice of equipment cannot be left to the manufacturer, which merely indicate where the equipment can be used, in accordance with the provisions and limitations of the certificate.
The responsibility of the installer is to follow the dictates of the project and to respect the equipment limits of use. Must be followed all the manufacturer instructions and the equipment must be installed as provided, without making any changes. For example, if we’d install an electrical panel made with Ex "d" enclosures, must be used only the entries provided by the manufacturer. It’s not allowed to make extra holes for the installation of additional cable glands not initially foreseen. Any modification to the equipment nullifies its safety and compliance with the reference standard and, thus, the validity of the certificate.
Once realized the plant, it must be periodically checked and maintained in the state of maximum efficiency and security.
To this end, it’s necessary an initial inspection carried out in accordance with IEC EN 60079-17 standard and set a plan for periodic audits. The maintenance service company is in charge of these activities and it will also provide the installation and maintenance operations of the individual equipment, following the dictates of IEC EN 60079-19 standard.