USEPA Method 7E is now the root method, not USEPA Method 6C. 

Methods will retain bias-correction detailed in USEPA Method 6C.

Bias determination as a percentage of span is retained at 5%.  However, “span” has been changed to “calibration span” which is equivalent to the concentration of the high calibration gas.

Required calibration gases are low (<20%) calibration span, mid (40-60%) calibration span, and high (100%) calibration span.

Measured values should be within 20-100% of the “calibration span.”

Between runs, calibration drift test determinations are still required to the extent practicable.

Analyzer Calibration Error Test must be within  ± 2% or 0.5 ppm of the calibration span, not the tag value.

Analyzer Interference tests remain a one time test except for major instrument modifications.

USEPA Method 6C interference tests can now be performed by challenging the analyzer with potential interferent gases.  The old procedure is still an alternative.

CEMs equipment heating now requires a temperature sufficient to maintain stack gas above the dew point, not a specific temperature (250°F).

Blended calibration gases are allowed provided they are made from Traceability protocol gases and any additional gas components are shown not to interfere with analysis.

USEPA Method 205 is allowed to prepare calibration gases from high concentration gases of EPA Traceability Protocol quality, except for 40 CFR Part 75 applications, which require administrative approval to use this technique.

NOx converter tests required before each test using the same procedure must meet 90% of gas concentration.  The method allows for correcting emissions using the converter efficiency.