Summary of the 1986 EPA (Environmental Protection Agency) National Performance Audit Program on Source Measurements

摘要

In 1986, the Quality Assurance Division conducted the National Audits for Stationary Source Test Methods. The audit materials consisted of: a disposable gas cylinder for Method 3 (Orsat analyzer), a calibrated orifice for Method 5 (DGM only), five simulated liquid samples each for Method 6 (SO2) and Method 7 (NOx), and two coal samples for Method 19. Participating laboratories sent their data to the Source Branch and in return received a written report comparing their results to EPA's. In the Method 3 audit, each parameter had only one concentration. The mean for CO2 was 3.7% from the expected (EPA) value. The mean for O2 was 0.4%. In the Method 5 audit, the mean value for all participants differed by 3.9% from the expected value. For the Method 6 audit, the average mean differed by 2.0% from the expected value, and in the Method 7 audit, the average mean differed by 5.0%. In the two coal audits, the parameters measured were sulfur, moisture, ash, and Btu content. On the average for the sulfur analysis, 90% of the participants measured within 10% of the expected value; for Btu, 99% of the participants measured within 10% of the expected value.