Title 40

PART 52 APPENDIX D



Appendix D to Part 52 - Determination of Sulfur Dioxide Emissions From Stationary Sources by Continuous Monitors

40:5.0.1.1.1.19.1.6.2 : Appendix D

Appendix D to Part 52 - Determination of Sulfur Dioxide Emissions From Stationary Sources by Continuous Monitors

1. Definitions.

1.1 Concentration Measurement System. The total equipment required for the continuous determination of SO2 gas concentration in a given source effluent.

1.2 Span. The value of sulfur dioxide concentration at which the measurement system is set to produce the maximum data display output. For the purposes of this method, the span shall be set at the expected maximum sulfur dioxide concentration except as specified under section 5.2, Field Test for Accuracy.

1.3 Accuracy (Relative). The degree of correctness with which the measurement system yields the value of gas concentration of a sample relative to the value given by a defined reference method. This accuracy is expressed in terms of error which is the difference between the paired concentration measurements expressed as a percentage of the mean reference value.

1.4 Calibration Error. The difference between the pollutant concentration indicated by the measurement system and the known concentration of the test gas mixture.

1.5 Zero Drift. The change in measurement system output over a stated period of time of normal continuous operation when the pollutant concentration at the time for the measurement is zero.

1.6 Calibration Drift. The change in measurement system output over a stated period of time of normal continuous operation when the pollutant concentration at the time of the measurement is the same known upscale value.

1.7 Response Time. The time interval from a step change in pollutant concentration at the input to the measurement system to the time at which 95 percent of the corresponding final value is reached as displayed on the measurement system data presentation device.

1.8 Operational Period. A minimum period of time over which a measurement system is expected to operate within certain performance specifications without unscheduled maintenance, repair or adjustment.

1.9 Reference Method. The reference method for determination of SO2 emissions shall be Method 8 as delineated in Part 60 of this chapter. The analytical and computational portions of Method 8 as they relate to determination of sulfuric acid mist and sulfur trioxide, as well as isokinetic sampling, may be omitted from the overall test procedure.

2. Principle and Applicability.

2.1 Principle. Gases are continuously sampled in the stack emissions and analyzed for sulfur dioxide by a continuously operating emission measurement system. Performance specifications for the continuous measurement systems are given. Test procedures are given to determine the capability of the measurement systems to conform to the performance specifications. Sampling may include either the extractive or nonextractive (in-situ) approach.

2.2 Applicability. The performance specifications are given for continuous sulfur dioxide measurement systems applied to nonferrous smelters.

3. Apparatus.

3.1 Calibration Gas Mixture. Mixture of a known concentrations of sulfur dioxide in oxygen-free nitrogen. Nominal volumetric concentrations of 50 percent and 90 percent of span are recommended. The mixture of 90 percent of span is to be used to set and to check the span and is referred to as the span gas. The gas mixtures shall be analyzed by the Reference Method at least two weeks prior to use or demonstrated to be accurate and stable by an alternate method subject to approval of the Administrator.

3.2 Zero Gas. A gas containing less than 1 ppm sulfur dioxide.

3.3 Equipment for measurement of sulfur dioxide concentration using the Reference Method.

3.4 Chart Record. Analog chart recorder, input voltage range compatible with analyzer system output.

3.5 Continuous measurement system for sulfur dioxide.

4. Measurement System Performance Specifications.

The following performance specifications shall be met in order that a measurement system shall be considered acceptable under this method.

Table I - Performance Specifications

Parameter a Specification
1. Accuracy a ≤20 percent of reference mean value.
2. Calibration Error a ≤5 percent of each (50%, and 30%) calibration gas mixture.
3. Zero Drift (2-hours) a ≤2 percent of emission standard.
4. Zero Drift (24-hours) a ≤4 percent of emission standard.
5. Calibration Drift (2-hours) a ≤2 percent of emission standard.
6. Calibration Drift (24-hours) a ≤5 percent of emission standard.
7. Response Time ≤5 minutes maximum.
8. Operational Period ≤168 hours minimum.