Maintenance of Ex-equipment and verification of its correctness may only be performed by companies or craftsmen who have registered equipment and workers for the performance of this type of work, according to all laws. Fulfillment of the conditions for processing such data and jobs is proven by a positive technical report for maintenance activities. Craftsmen or the company that won the job in the competition offers the following services: - Ex equipment installations (TN-IN) - Ex-equipment maintenance (TN-ODA) -Repair of ex-equipment (TN-PO) The authorized person must therefore carry out a correctness check, which in accordance with the law is obliged to control Ex-equipment and installations in the following states: -Ex equipment is checked according to a pre-agreed plan - A visual and then control inspection is performed -Ex equipment must be checked and submitted for inspection accompanied by appropriate documentation - And in accordance with all the fulfilled conditions, he must have a maintenance contract Ex-zone is defined as an area where an atmosphere that is susceptible to ignition or explosion can be contained only when the atmosphere contains a large amount of dangerous gases, dust or steam. Ex atmosphere is a mixture of substances that mix with air and as a result cause conditions in the atmosphere that ignite in the form of dust, steam or gas and thus spread over the entire area.