What size gal pipe do you use macca?
Three inch for the main runs, inch and a half or two inch for branches and either three quarter or half inch for the droppers, (usually half inch) in the pic I posted you can see one of the three inch above the roller door on the right and a balance pipe running across the top of the spray booth and gantry, we run the three inch in a grid, one down each side of the factory and then run a three inch pipe between them every eight metres, the wall on the left is actually a dividing wall there is another three inch on that side.
They run a bloody big bead blaster along with a heap of CNC's, so when the blaster kicks in you need to make sure the CNC,s have enough air otherwise the result aint pretty
macca