Performance Evaluation and Myths regarding Radon Analysis via E-perms: Actual Field

This paper reports field results of E-PERMS in both (lie S-Chamber and their keeper caps. Hie results have been compiled during the past two years covering over 5,000 measurements. Data has been grouped to show precision (co-located tests), accuracy (radon chamber results), and electret stability. The latter results were also broken down into S-Chamber versus keeper cap versus electret series. Besides the aforementioned, a major emphasis will be comparing on-site E-PERM data versus those E-PERMS mailed overnight throughout the country. Overall the data showed that the E-PERMS are accurate and very precise. However, with regard to electret stability, older series and physically older electrets within a series appear to be somewhat more stable or less sensitive than newer electrets. Nevertheless, there is no difference when comparing the results of E-PERMS measured on site versus those air mailed back and forth to the same analysis lab for measurement.