EPA Methods List with Links



US EPA Method 20 - Determination Of Nitrogen Oxides, Sulfur Dioxide, And Diluent Emissions From Stationary Gas Turbines



1.0 Scope and Application

What is Method 20?

Method 20 contains the details you must follow when using an instrumental analyzer to determine concentrations of nitrogen oxides, oxygen, carbon dioxide, and sulfur dioxide in the emissions from stationary gas turbines. This method follows the specific instructions for equipment and performance requirements, supplies, sample collection and analysis, calculations, and data analysis in the methods listed in Section 2.0.



1.1 Analytes.

What does this method determine?



1.2 Applicability.

When is this method required?The use of Method 20 may be required by specific New Source Performance Standards, Clean Air Marketing rules, and State Implementation Plans and permits where measuring SO2, NOx, CO2, and/or O2 concentrations in stationary gas turbines emissions are required. Other regulations may also require its use.

AnalyteCAS No.Sensitivity
Nitrogen oxides (NOx) as nitrogen dioxideNitric oxide (NO)Nitrogen dioxide (NO2)10102-43-910102-44-0Typically <2% of calibration Span
Diluent oxygen (O2) or carbon dioxide (CO2)Typically <2% of calibration Span
Sulfur dioxide (SO2)7446-09-5Typically <2% of calibration Span


1.3 Data Quality Objectives.

How good must my collected data be?Refer to Section 1.3 of Method 7E.



2.0 Summary of Method

In this method, NOx, O2 (or CO2), and SO2 are measured using the following methods found in appendix A to this part:

(a) Method 1—Sample and Velocity Traverses for Stationary Sources.

(b) Method 3A—Determination of Oxygen and Carbon Dioxide Emissions From Stationary Sources (Instrumental Analyzer Procedure).

(c) Method 6C—Determination of Sulfur Dioxide Emissions From Stationary Sources (Instrumental Analyzer Procedure).

(d) Method 7E—Determination of Nitrogen Oxides Emissions From Stationary Sources (Instrumental Analyzer Procedure).



3.0 Definitions

Refer to Section 3.0 of Method 7E for the applicable definitions.



4.0 Interferences

Refer to Section 4.0 of Methods 3A, 6C, and 7E as applicable.



5.0 Safety

Refer to Section 5.0 of Method 7E.



6.0 Equipment and Supplies.

The measurement system design is shown in Figure 7E-1 of Method 7E. Refer to the appropriate methods listed in Section 2.0 for equipment and supplies.



7.0 Reagents and Standards

Refer to the appropriate methods listed in Section 2.0 for reagents and standards.



8.0 Sample Collection, Preservation, Storage, and Transport



8.1 Sampling Site and Sampling Points.

You must follow the procedures of Section 8.1 of Method 7E.



8.2 Initial Measurement System Performance Tests.

You must refer to the appropriate methods listed in Section 2.0 for the measurement system performance tests as applicable.



8.3 Interference Check.

You must follow the procedures in Section 8.3 of Method 3A or 6C, or Section 8.2.7 of Method 7E (as appropriate).



8.4 Sample Collection.

You must follow the procedures of Section 8.4 of the appropriate methods listed in Section 2.0. A test run must have a duration of at least 21 minutes.



8.5 Post-Run System Bias Check, Drift Assessment, and Alternative Dynamic Spike Procedure.

You must follow the procedures of Sections 8.5 and 8.6 of the appropriate methods listed in Section 2.0.



9.0 Quality Control

Follow quality control procedures in Section 9.0 of Method 7E.



10.0 Calibration and Standardization

Follow the procedures for calibration and standardization in Section 10.0 of Method 7E.



11.0 Analytical Procedures

Because sample collection and analysis are performed together (see Section 8), additional discussion of the analytical procedure is not necessary.



12.0 Calculations and Data Analysis

You must follow the procedures for calculations and data analysis in Section 12.0 of the appropriate method listed in Section 2.0.



13.0 Method Performance

The specifications for the applicable performance checks are the same as in Section 13.0 of Method 7E.



14.0 Pollution Prevention [Reserved]



15.0 Waste Management [Reserved]



16.0 Alternative Procedures

Refer to Section 16.0 of the appropriate method listed in Section 2.0 for alternative procedures.



17.0 References

Refer to Section 17.0 of the appropriate method listed in Section 2.0 for references.



18.0 Tables, Diagrams, flowcharts, and Validation Data

Refer to Section 18.0 of the appropriate method listed in Section 2.0 for tables, diagrams, flowcharts, and validation data.