George, the purpose for the exception is to allow installation of new equipment in an otherwise non-conforming space.
I agree we should be helping them find a better solution if possible. I would certainly want more lateral space if the height was low.
I got into this at the Ca-D-Zan mansion in Sarasota. They had several "tight" equipment rooms. In one of the ugly ones I required a disconnect at the door so they could kill all the equipment before they went in. It was a 1920s Otis elevator controller that they wanted to restore. If you ever saw the movie "Hotel" that was the thing that was arcing at the end. This building was restored as a museum and they wanted the original equipment. The room it was in was the only place it would go but the head room was more like 5'5 than 6'6. We did remove everything else we could to open the room up.
They had "in sight" disconnects on all mechanical equipment in the project.
When I left it they had documented LOTO procedures in place for the maintenance staff but we know how that works.
