Have you ever wrestled with remembering when a liquid fertilizer tank needs to be inspected next or had a debate in the office as to how often the liquid storage tanks need to be inspected? With no federal regulations on liquid fertilizer tank inspections, inspection timing can be confusing. The Fertilizer Institute, individual state statutes and regulations, and insurance policies are sources that provide guidance on the types of inspections to be completed and the timing for each type.
The Fertilizer Institute recommends above ground fertilizer tanks (ASTs) be inspected according to the risk-based inspection Standard of API 653. Within this Standard, Routine Monthly External In-Service “Walk Around” Inspections, Formal External In-Service Inspections, and Formal Internal Out-of-Service Inspections are required. Monthly “Walk-Around” Inspections are conducted by the tank owner, leaving the scheduling of these inspections up to the needs and uniqueness of each tank operation. However, the timing for formal API 653 inspections that should be performed by an API certified inspector can be required by various entities. Because no federal regulations apply, tank inspection requirements are mostly driven by state law. Therefore, required types of inspections and corresponding frequencies vary by the state location of the tank. While most states do have inspection requirements that are usually tied to obtaining or renewing an operation license or permit, some states do not have specific inspection requirements. Heartland Tank Services keeps track of all state inspection requirements and would gladly help you determine when your state laws require an inspection be completed. Another entity that may also require you to conduct tank inspections is your insurance company.
Insurance agencies have realized that mandating inspections before issuing or re-issuing tank insurance policies aids in protecting their liability and in turn, their insured, the tank owner. Leading insurance companies are now requiring tanks be built to API 650 Specifications as well as inspected according to the API 653 Standard. With insurance companies adding these requirements, make sure to avoid the potential duplicate inspection. If not coordinated, you may need one inspection to fulfill the state requirements and a second inspection to meet your insurance needs. Some insurers understand that states have inspection requirements, but it is important that you, the tank owner/operator, understand the timing of the state and insurance required inspections so that one inspection can serve both purposes. Talk with your insurance agent to understand the timing of their inspection requirements so that the insurance inspection requirement can be coordinated with any state mandates. Again, Heartland Tank Services will gladly help you in this process.
Notwithstanding the state and insurance requirements, API 653 sets out a guideline for the frequency of formal inspections. Again, these formal inspections should be completed by API certified inspectors to ensure that a complete API 653 inspection is performed according to the API Specifications. For formal external inspections, API 653 Section 18.104.22.168 recommends this type of inspection every 5 years or a calculation of years based on the current shell thickness and the shell corrosion rate, whichever is less. Formal external inspections can be performed while the tank is in service.
A test that should be a component of the formal external and internal inspection is the Ultrasonic Thickness (UT) inspection. UT testing is required by API 653 every 5 years if the corrosion rate is unknown, and when it is known, the interval can be longer based on a particular calculation provided in the API 653 Standard. UT testing is used to determine the thickness of the shell, floor, and roof plates. The inspector will use a device that sends a high frequency sound energy wave (a sound undetectable to humans) through the material being tested and the gauge measures the time it takes for the wave to be reflected back through the material. The thickness reading is then compared to the minimum plate thickness requirements of API 653 based on the diameter and height of the tank as well as the specific gravity of the product being stored.
Finally, API 653 sets out specifications as to how to conduct formal internal inspections of an AST. Guidelines within API 653 suggest conducting a formal internal inspection every 10 years for tanks storing oil products. However, due to the corrosive nature of fertilizer products, The Fertilizer Institute recommends internal inspections to be conducted more often than the guidelines of API 653. If the fertilizer tank contains an internal bladder system or internal coating, The Fertilizer Institute recommends internal inspections be performed at least every 5 years. For all other tanks, the interval is based on the corrosion rates of the tank but should not exceed conducting an inspection every 10 years. To determine the corrosion rate of a tank, an initial API 653 inspection must be done within the first 10 years after the tank is built. Again, while these are the inspection frequencies recommended by The Fertilizer Institute, some states have created different requirements. Therefore, the key is for you, the tank owner/operator, to be knowledgeable as to what requirements you must fulfill.
Determining when you need to conduct an inspection can be complicated depending on the state location of the tank and the requirements of your insurance company. Heartland Tank Services tracks all of this information and can help untangle this web of requirements for you. We keep a list of the inspection requirements for every state and can provide you an inspection schedule that will meet your needs. Once you have had an inspection done by Heartland Tank Services, we also automatically track the date of the next inspection for that tank and will send you a reminder when the next inspection is due. If you would like assistance in determining the requirements in your state, please call us at Heartland Tank Services, and we would be glad to help you.