I work on a Core & Shell project based in Paris and i have a question about ASHRAE 90.1 Standards, and more especially on the possibility to derogate to certain requirements. On this project, 3 labels are targeted : HQE / WELL / LEED

My question if about the Requirement that said the SGHC must be < 0.4 for every windows. In the case of our project, there are 2 patios of 7 floors, with a low access to natural lightning. The study we did, according the HQE requirements, oblige us to use extra clear glazing (with SGHC > 0.4) . If not, the HQE certification wont be possible. 

Could you confirm, in this case, that we can derogate to LEED requirements, and could you also explain how di we need to justify this derogation.

In a general way, if there are other requirements of ASHRAE 90.1 that can't be meet, how do we justify it ? 

Thank you for your help.