Understanding the Above Ground Storage Tank Inspection Standards
By definition, aboveground storage tanks are containers used for storing a large quantity of industrial products, petroleum products, or chemicals.
Aboveground Storage Tanks have become a staple for a wide range of industries. Be it mining, oil & gas, transportation, construction, food processing, or manufacturing; aboveground storage tanks are used everywhere. And why not? ASTs are made of sturdy metal and can hold even combustible material. However, since they are placed above the ground and exert significant pressure on the surface, they are vulnerable to crevice corrosion, pitting, and even leakage. Thus, aboveground storage tanks are subject to various inspection standards like API, SPCC, NFPA, AWWA, and more. And only certified API or water tank inspection services providers can conduct such inspections.
This blog discusses the SPCC tank inspection standard in detail.
According to the 40 CFR 112.2 of the Oil Pollution Prevention Regulation, if aboveground storage tanks contain oil and the tank storage facility fulfills the criteria stated in the regulation, they should be managed as per the norms of the Federal Oil Pollution Prevention regulation 40 CFR part 112. The code requires the operator/owner of the ASTs to draft and implement an SPCC plan.
The SPCC Rule is applicable to ASTs facilities if:
- The AST has a storage volume of 1,320 gallons or more in tanks with a capacity of over 55 gallons;
- The facility has reasonable grounds to release oil to the adjoining shorelines or navigable water;
- The facility is not related to the transportation sector.
The 40 CFR 112.8(c)(6) code states that the facility operator should periodically examine and monitor each aboveground storage container for structural integrity whenever they make alterations to the tanks.
STI SP001 for Aboveground Storage Tanks Assessment
The STI SP001 is designed and established by the Steel Tank Institute to help tank facility owners of the shop-built aboveground storage tank to manage tank integrity. The SPCC standard outlines the requirements for evaluating the tanks and how to assess their suitability of the tanks. The STI SP001 standard applies to tanks that store flammable, stable, and combustible liquids. In some instances, the standard can be applicable to ASTs storing other liquid content. The standard includes shop-built aboveground storage tanks like double or single-walled steel tanks, steel diked tanks, portable storage vessels, and concrete tanks with 75,000 gallons or less capacity.
Besides this, the STI SP001 standard also covers field-erected aboveground storage tanks of size 30 feet in diameter and 50 feet in height.
The STI SP001 has detailed what tank inspection the facility owner should undertake and how often tank inspection services experts should conduct the assessment. The regulation sets the inspection norms according to size, design, and configuration. This simplifies the SPCC compliance process and removes the guesswork.
The STI SP001 standard divides the tanks into three risk categories. Factors such as containment level, spill protection criteria, and tank structure are considered when categorizing the tank’s risk level. Category 1 implies that the tanks are at low risk, while category 3 means the tanks are at high risk. Further, the risk category and other information about the tank help the tank owners determine the frequency of the tank inspection.