S.C. Code Regs. 8-1229. IRC Section M1411.6 Insulation of refrigerant piping

Pipings and fittings for refrigerant vapor (suction) lines shall be insulated with insulation having a thermal resistivity of at least R2.5 hr. ft2 F/Btu and having external surface permeance not exceeding 0.05 perm [2.87ng/(s × m2 × Pa)] when tested in accordance with ASTM E96.