EPA Method 6C is a procedure for measuring sulfur dioxide (SO2) in stationary source emissions using a continuous instrumental analyzer. The use of Method 6C may be required by specific New Source Performance Standards, Clean Air Marketing rules, State Implementation Plans, and permits where SO2 concentrations in stationary source emissions must be measured, either to determine compliance with an applicable emission standard or to conduct performance testing of a continuous emission monitoring system (CEMS). Other regulations may also require the use of Method 6C.
The essential components of the measurement system are the same as those in sections 6.1 and 6.2 of Method 7E, except that the SO2 analyzer described in section 6.2 of this method must be used instead of the analyzer described in section 6.2 of Method 7E. You must follow the noted specifications in section 6.1 of Method 7E. You may use an instrument that uses an ultraviolet, nondispersive infrared, fluorescence, or other detection principles to continuously measure SO2 in the gas stream and meets the performance specifications in section 13.0. The low-range and dual-range analyzer provisions in sections 220.127.116.11 and 18.104.22.168 of Method 7E apply.