Which of the following is NOT a common deficiency affecting the structural integrity of tanks?

The choice highlighting proper placement or compaction of backfill materials is identified as not a common deficiency affecting the structural integrity of tanks because it pertains to the correct practices necessary for ensuring stability and longevity of the installation. Proper placement and compaction are critical to creating a stable foundation; when executed correctly, they minimize voids that could lead to settlement or other structural issues.

Inadequate backfill practices can indeed lead to various deficiencies. For instance, using incorrect backfill materials or leaving rocks and debris in the excavation can create uneven support and extend the lifespan of potential structural issues. Migration of backfill materials can also compromise the tank’s integrity over time, as these materials may erode or shift, altering the foundational support intended for the tank.

Thus, the emphasis on proper placement or compaction of backfill is not linked with deficiencies in the same manner as the other factors, as these practices are intended to prevent structural failures rather than contribute to them.