Nick,
Very similar to airport grounding. The lightning system was separate from the electrical system.....kinda. The lightning counterpoise ringed the buildings (often a mile or a shade over in length) with 2/0 cu., ground rods fairly often in the system, but at least bonded to the building steel every 50', and the down leads were bonded to the building steel as they penetrated the roof.

The electric service was pretty standard grounded, to the water services (don't forget the sprinkler system) and the building steel, which is how it tied to the lightning system, plus all the extra electrical equipment ties to the bldg steel, xfrmrs etc..

Now don't forget the ductwork, and you can call the FAA for a flight path [Linked Image]