SIRA (Statistical Inventory Reconciliation Analysis) - SIRA was developed in the mid 1980’s as a means of identifying characteristic sources of error in conventional fuel product inventory records. Since the method is able to identify operational errors such as delivery discrepancies, meter errors, improper tank charts, theft, pilferage, and blending errors. SIRA can identify underlying leaks in tanks and associated lines at the EPA’s monthly monitoring standard of 0.2 gallons per hour. There are two variants of SIRA, which are used by retail petroleum operators:

          1. SIRA (S1) - S1 analysis is conducted for facilities where daily tank measurements of sales, deliveries, and product heights and volumes are manually recorded by the tank operator and provided on paper, spreadsheets, touch-tone data entry or web entry to WRA for analysis.

          2. SIRA (S2) - S2 analysis is conducted for facilities which are equipped with automatic tank gauges and point of sale systems which can electronically record daily sales transactions. The site operator is not required to manually record conventional inventory observations because the required daily data can be accessed electronically.  S2 data is batched daily and sent to WRA for analysis