Where the purchaser assesses costs using a life-cycle approach, it shall indicate in the tender documents the data to be provided by tenderers and the method it will use to determine the life-cycle cost on the basis of those data.
The method used to assess the costs attributed to environmental externalities shall comply with all the following conditions:
a) It shall be based on non-discriminatory and objectively verifiable criteria;
b) It shall be accessible to all interested parties;
c) It shall imply that the required data can be provided with a reasonable effort by normally diligent economic operators.