In the event of the installation of new heavy equipment mentioned in 2° of article R. 6122-26 which does not lead to the threshold mentioned in the first paragraph of II of article R. 6123-161 being exceeded, as well as, regardless of the number of authorised units held by the holder, in the event of the replacement of one of these units by a unit of the same type, the holder informs the competent regional health agency of the characteristics of this unit before it is put into service.
When the holder of the authorisation has a number of items of equipment covered by 2° of Article R. 6122-26 in excess of this same threshold, the replacement of one of these items of equipment by an item of equipment of a different nature is subject to the implementation of the procedure mentioned in the second paragraph of Article R. 6122-39.
Any installation of equipment covered by 2° of article R. 6122-26 in cases other than those mentioned in the two previous paragraphs is subject to modification of the initial authorisation.