Ensuring your pressurized tanks and other equipment meet API and EPA standards is an essential aspect of running your business. It can be challenging to keep up to date on current codes and to know who to trust for inspections to ensure your equipment is kept within code parameters. 

Complying with regulations is essential not just for your business’s bottom line, but also for the protection of employees and the environment. It also keeps your tanks in good condition for longer, which can save you money over time. 

Thankfully, there are ways to ensure that your pressurized tanks are up to code and in good working order. This guide will explain API and EPA codes and help you make the right decisions regarding tank maintenance. 

What are Shop-Built Tanks?

 Shop-Built tanks are metal tanks designed and fabricated to hold specific types of materials. The main types of tanks include: 

Thermal Storage Tanks: These are designed to maintain internal temperatures or heat a product before moving. The heating system used will depend on the product being stored and the tank, but it usually involves heating coils installed inside the tank itself. They can be used for holding chemicals, pulp, animal products, petroleum, or water. They are regulated by codes AWWA D100 or API 650. 

Fire-rated Tanks: Fire-rated tanks must be highly durable and are usually double-walled with six inches of concrete insulation between two walls. This tank type is used to hold petroleum products and is regulated by codes UL 2085, UL 2244, STI Standard F941, and ULC S655. 

High-pressure Vessels: High-pressure vessels differ from tanks in that they are designed to hold higher pressures than those in tanks under API 650 and 620. They can handle internal pressures between 15 and 3,000 PSI and hold chemicals, water, and petroleum products. They are regulated by codes ASME Section VIII Div 1

Atmospheric/Low-Pressure Tanks: These tanks are designed to hold low pressures that range from ambient to 02.5 PSI. They are most often used to handle water, wastewater, chemicals, petroleum, and pulp. Applicable codes include API 650, NFPA 22, AWWA D100, D102, D652, UL 142, and STI F921. 

Tanks may also have varying shapes, each designed for a specific purpose. Shapes may depend on the products being held, as well as placement. Shapes may include: 

  • Shovel bottom
  • Rounded heads
  • Flat bottom
  • Cone bottom
  • Vertical
  • Horizontal

The type you use for your product will depend on the type of materials being handled. It will also determine which codes you must follow, the shape of your tank, and other aspects of construction. 

Why are there API and EPA Codes? 

The standards and codes set out by the EPA and API organizations are put in place by leaders in the industry. They exist to ensure pressurized and atmospheric shop-built tanks are designed and constructed to ensure the safety of employees and the environment. They also ensure tanks are built to last as long as possible. 

Codes cover multiple areas of design and construction, including the materials used, foundations, weld style, and plate thickness. They may also indicate proper coating and maintenance for tanks. 

What are Some of the Most Common Codes? 

There are several principal codes and industry standards that tanks must comply with. While this isn’t an exhaustive list, it includes most of the principal codes businesses keep in mind during design, construction, and maintenance. 

API 650 – This code presents standards for the fabrication of oil storage tanks, including the design, welding, assembly, fabrication, installation, inspection, and final testing. Tanks that fall within these guidelines are usually atmospheric, but they may contain little pressure that doesn’t exceed the weight of the roof plates. They’re typically used for petroleum-based products, including gasoline, produced water, oil, crude petroleum, and other related chemicals. 

STI SP001 – This code is the standard, which has been developed by the Steel Tank Institute and Plate Fabricators Association, to regulate inspection requirements for welded metal tanks as well as shop-fabricated or small field erected ones such those found in portable container sizes like 55 gallons drums. It also covers all other types of smaller containers made from either aluminum (such an IBC) steel plating their components depending on what they’re designed entirely around – these can include both transportable tank systems but even some rigid truck bodies.

There are two categories of inspections under SP-001 – Periodic and Formal Inspections.

Period inspections are performed by client-trained personnel and are performed daily, monthly, or yearly. Monthly and yearly inspections are conducted in accordance with a code checklist, kept on file, and updated. 

Formal inspections are performed by STI-certified inspectors and the intervals for these inspections depend on the size and type of tank container. 

AWWA D100 – This code governs welded storage tanks, including the fabrication, foundation, materials, hardware, testing, and quality assurance. There are various types of water tanks, and some will fall under the guidelines of additional codes, which may include:

  •   AWWA D102: This includes the standards for coating steel water tanks. This process is typically done via painting or lining and is done directly after fabrication.
  •  AWWA D652: This includes standards for disinfecting tanks that are made to hold drinking water. This is usually done after the tank has been delivered to its destination but before being used. 

UL 142 Certification – This involves the NFPA 30 flammable and combustible liquids code and regulates the fabrication of tanks used for flammable and combustible liquids. This type of tank may also fall under the F921 regulation put out by the steel institute. While other types of tanks may be shop-built or field-erected, this category can only govern shop-built models. Tanks built within the guidelines of UL 142 will be given the UL Listing Mark stamped to the side of the tank. 

UL 142 fabrication guidelines include requirements regarding drain and gauge openings, welded joints, connections, fittings, manholes, and coatings. It also covers these tanks’ testing and quality assurance, which tests them for buoyancy, hydrostatic strength and load, tank support, top-loading, tank leakage, support, and lift tug tests. These tests are designed to ensure the tank is structurally sound. 

US 2085 – While tanks that meet this standard are similar in design and function to UL 142, they are additionally reinforced and double-walled, offering an interstitial space between two shells filled with lightweight concrete. This makes the tanks resistant to impact from collisions, natural disasters, and even bullets. F941 is a similar certification offered by the Steel Tank Institute. 

How to Make Sure Your Tank Meets Code Requirements 

We are only as good as the service we provide, and we go the extra mile to ensure all of our personnel are trained to industry standards. 

At NDT Tanknicians, we embrace the tough challenge set in place to be certified by entities such as the Environmental Protection Agency (EPA,) American Petroleum Institute (API,) Steel Tank Institute (STI,) American Society for Nondestructive Testing (ASNT,) and the National Association of Corrosion Engineers (NACE,) to name a few. 

We’re capable of providing top-to-bottom coverage for all of your Storage Tank requirements; servicing a broad spectrum of clientele, both small and large. 

Our ability to streamline an entire project gives us an edge over the competition by providing our clients with the peace of mind and convenience of trusting one service provider to become familiar with all of their current and future needs, rather than half a dozen. This keeps costs to a minimum, quality control consistent and communication among crews seamless. 

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