C505 Change of use and ASHRAE compliance pathway

[energyarch77]

We have a renovation project under IECC 2021, undergoing a change of occupancy/use and (we assume for now) an increase in energy usage. Per C505.1, this would trigger whole building upgrades to comply with the energy code (with the noted exceptions under 505.) What happens if we wish to use ASHRAE 90.1 as the compliance pathway, though? I would think that C505 still applies, meaning we would apply ASHRAE as if it were a new building, right?

However, the 10% leniency that 505.1 provides to the other two compliance pathways doesn't apply to ASHRAE, so we wouldn't get that.

 

[energyarch77]

Flow chart related to my question.