Ex hazardous area classification vs Ex personnel competencies

Who is legal to make HAC (hazardous area classification)?
1) acc to IEC/EN 60079-10-1 anyone who is fully familiar with the technology applied there and has basic knowledge of explosion protection.
Zitat: “4.4 Competence of Personnel
The area classification should be carried out by those who understand the relevance and significance of the properties of the flammable substances, principles of gas/vapour dispersion and those who are familiar with the process and the equipment. It may be beneficial for other engineering disciplines, e.g. electrical and mechanical engineers, and personnel with specific responsibility for safety to be part of and have an input to the area classification process. The competency of the person shall be relevant to the nature of the plant and methodology used for carrying out the area classification. Appropriate continuing education or training should be undertaken by personnel on a regular basis where required.
NOTE Competency can be demonstrated in accordance with a training and assessment framework relevant to national regulations or standards or user requirements.”
2) it shall not go forgotten that hazardous area classification is part of EPD (explosion protection documentation according to ATEX 137), where competency is defined as per follows: “2.8. Before a workplace containing places where explosive atmospheres may occur is used for the first time, its overall explosion safety must be verified. Any conditions necessary for ensuring explosion protection must be maintained. Such verification must be carried out by persons competent in the field of explosion protection as a result of their experience and/or professional training.”
Which gives the idea of dual HAC. There shall be a HAC before starting anything in a possible hazardous environment, but before finalizing there shall be a second HAC in order to avoid that some factors have not been considered and might make the site Ex dangerous again.
Keep up good work!