Inventory Control

INVENTORY CONTROL is like balancing a checkbook. Every month the product volume is balanced between what is delivered and what is removed from the tank. This process involves daily measurements of tank volume taken with a gauge stick. If your "account" does not balance, the tank may be leaking. Inventory control does not need to be performed by specially trained people and does not require the cessation of tank operations.

OPERATION

Daily measurements of product depth are coverted to volumes using a calibration chart (usually supplied by the tank manufacturer). Volumes are recorded on a ledger. Daily deliveries of product are also recorded. At least once a month the gauge measurements, deliveries, and removals from the tank should be reconciled. If the calculated imbalance is greater than or equal to 1% of the tank's flow through volume, plus 130 gallons, the tank system may be leaking.

If the tank is not level, it may be necessary to create your own volume-height calibration chart by incrementally adding known volumes of product and measuring gauge depths.

REGULATORY REQUIREMENTS

  1. Inventory control must be used in conjunction with periodic tank tightness tests.

  2. The gauge stick should be long enough to reach the bottom of the tank and marked so that product level can be determined to the nearest one-eighth of an inch.

  3. A monthly measurement must be taken to identify any water at the bottom of the tank.

  4. Product deliveries must be made through a drop tube that extends to within one foot of the tank bottom.

  5. Product dispensers must be calibrated to the local weights and measures standards.

COSTS

The main costs are the gauge stick and perhaps some product-finding paste. The price of these items is under $200.

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