if it is detached and treated s a separate building, you would have to assume a property line between the structures. I assume the the closeness of the two buildings to the assumed property lines would not allow openings in walls per table 602. If it is considered as one building, then if a building is protected by NFPA 13, the only way to eliminate the fire sprinklers is if you meet one of the twelve exceptions permitted by NFPA 13.
Another exception is to use the pedestrian walkway exception in Chapter 31 - If it fails to meet that criteria as well, I would also make the detached open sided building be protected by a fire sprinkler system or meet the requirements of T602 for closeness to the assumed property line in order to treat it as a separate building by the building code.
However, without having a site plan or other details provided, the above is the hypothetical approach I would have used when serving as fire marshal/ or commercial plan reviewer.
Helpful Hint since nobody likes being told NO -
Look in NFPA 13 in regards to having to fire sprinkler drive-through (like a bank), exceptions are provided for passenger drop off canopies as LONG AS PARKING is not allowed - (No Parking Signs, No loading or unloading of trucks, No combustibles, and Security is provided to monitor traffic at this location, etc.) You may have to look at NFPA 13 technical interpretations to find this tidbit. The items listed above were the official interpretation used to enforce this when people wanted the detached passenger unloading/ loading cover is the last fire district I worked in.
If this exception was provided, we required it to be documented on the plan set for permanent record storage.
