I checked through our NCMA TEKS Book and they had only one "old" article concerning corrosion of reinforcing in masonry walls. Essentially, all it stated was that ties require 1/2" cover in non-exposed conditions and 5/8" cover in exposed conditions. Other than that, it simply called for galvanizing. Is this an existing condition with corrosion, or are you trying to avoid corrosion in a new design?