Why does STI SP001 require internal inspections when one cannot easily access the inside of a small shop-fabricated tank?
STI SP001 does not mandate entry into a tank for any tank under 30,000 gallons (113,529 liters). For tanks under 30,000 gallons, either internal inspections are not required, or else an alternative is given with the use of leak-test inspections. Tanks larger than 30,000 gallons usually have manways to allow personnel entry.