The use of proper backfill is critical to long term underground storage tank performance. Only approved backfill is allowed when installing fiberglass storage tanks and the backfill must meet ASTM C-33 Fine Aggregate requirements for deleterious substances and soundness. To verify that your backfill material meets our specifications, use the Approved Backfill Calculator. Crushed concrete or limestone CAN NOT be used as backfill.

To begin: Select the backfill material you wish to verify. Then enter the required data from your provider’s sieve analysis and if your material meets our specification, you will receive a confirmation email from our Tank Technical Support department.

APPROVED BACKFILL

CALCULATOR