Statistical Inventory Reconciliation - SIR

Statistical Inventory Reconciliation has been approved as an “other” or alternative release detection method for years, but is now officially outlined in the regulations. To properly conduct SIR, owners/operators must:

• Take readings to at least the nearest 1/8th inch (using an automatic tank gauge meets this criteria).
• If using a tank stick to take measurements, a drop tube must be installed.
  If using a tank stick, the correct tank chart must be used for converting the height reading to gallons.
• Be able to accurately measure the full range of the tank height.
• Check for water at least once every 30 days.
• Compare delivery reports to pre- and post-delivery measurements.
• The SIR vendor or program must be approved by the National Work Group on Leak Detection Evaluations.
• Conduct SIR in accordance with the NWGLDE certification and the manufacturer’s protocol.
• The monthly data must be submitted, evaluated and reported by the 15th of the following month (e.g., June’s data must be submitted to the vendor or input in the software program, evaluated, and the final report back to the owner/operator no later than July 15).
• Retain all supporting data, including the daily inventory, sales, deliveries, overages/shortages, monthly detailed reports and exception information, if applicable.
• Evaluate independent tank systems separately, even if they contain the same products. Manifolded systems are typically evaluated as one system.