S.C. Code Regs. § § 61-62.5.1.I
No one shall discharge to the ambient air from any existing source constructed prior to February 11, 1971, smoke which exceeds opacity of forty (40) percent. The forty (40) percent opacity limit may be exceeded for soot blowing, but may not be exceeded for more than six (6) minutes in a one hour period nor be exceeded for more than a total of twenty-four (24) minutes in a twenty-four (24) hour period. Emissions caused by soot blowing shall not exceed sixty (60) percent.
No one shall discharge to the ambient air from any source constructed on or after February 11, 1971, smoke which exceeds opacity of twenty (20) percent. The twenty (20) percent opacity limit may be exceeded for soot blowing, but may not be exceeded for more than six (6) minutes in a one hour period nor be exceeded for more than a total of twenty-four (24) minutes in a twenty-four (24) hour period. Emissions caused by soot blowing shall not exceed sixty (60) percent.
Owners and operators shall, to the extent practicable, maintain and operate any source including associated air pollution control equipment in a manner consistent with good air pollution control practices for minimizing emissions. In addition, the owner or operator of fuel burning sources except natural gas and propane fired units, shall maintain a log of the time, magnitude, duration, and any other pertinent information to determine periods of startup and shutdown and make available to the Department upon request.
The method which is approved by the Department for determining compliance with opacity limitations under this Section is EPA Reference Method 9 (40 Code of Federal Regulations (CFR) 60, Appendix A, as revised July 1, 1986). Alternate methods may be utilized only if approved in advance by the Department and by the Environmental Protection Agency (EPA).
S.C. Code Regs. § 61-62.5.1.I