Conductors should not be painted, since this will increase impedance. Gradual bends always should be employed to avoid flashover problems. Building structural steel also may be used in place of downconductors where practical as a beneficial subsystem emulating the Faraday Cage concept. 4.3 Bonding assures that unrelated conductive objects are at the same electrical potential. Connector bonding should be exothermal and not mechanical wherever possible, especially in below-grade locations.
Mechanical bonds are subject to corrosion and physical damage.
HVAC vents that penetrate one structure from another should not be ignored as they may become troublesome electrical pathways. The grounding system must address low earth impedance as well as low resistance. A spectral study of lightning's typical impulse reveals both a high and a low frequency content. The grounding system appears to the lightning impulse as a transmission line where wave propagation theory applies. Earth loops and consequential differential rise times must be avoided.