Have never developed an ERP so can't help there but also don't see how a BOM fits the requirement, which I understand is to create a drawing db. Maybe I missed the point. IMO if you had an equipment location table you would simply link the drawing to the location. By location, I don't mean simply physical locations; it's just what we called it.
This method allows you to associate physical items as well as other entities to any place in the hierarchy. Those other "things" can be costs/expenses, safety related items such as safe work permits, accident data, whatever you want. An example of a location string might be (to the best of my recollection)
KENL.NPSS.TRUC.0165.STER which translates to
- physical property location
- non production sales or services
- Truck Garage
- unit number
- steering system
You could have as many levels as you need but at some point it should be enough to work off of a list of drawings. For example, If I wanted to locate a drawing for L2 steering bogey assembly it would be at the last level but there would be a list of drawings because there are several of these assemblies. Maybe I'm out to lunch, but shouldn't a drawing that is comprised of items for which there are other drawings have a list of those drawing numbers as part of the drawing? So you'd have a way to locate those drawings, not by location but by drawing number shown on the drawing?
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.