What to Do if STI, UL, or SwRI Labels Are Missing or Damaged on a Welded Steel Storage Tank 

Storage tanks come with multiple labels, each serving a specific purpose. However, there are labels that are especially critical and cannot be reproduced once lost: the STI serial number label and the UL or SwRI certification labels.

These labels are unique identifiers that are applied to the tank at the time of construction by a licensed manufacturer. Their presence signifies that the tank met all applicable standards for new tank construction at the time of fabrication.

Why Certification Labels Matter

These labels verify that the tank was built to industry standards, help confirm the tanks are being used for its intended purpose, and that it meets requirements set in fire and building codes. If the labels become unreadable or fall off due to weathering or age, it makes it more difficult to confirm the tank met these requirements at the time of fabrication.

While tanks are built to last, the degradation of these labels often coincides with the tank aging—bringing into question the standard of construction of the equipment and its suitability for use in its current application.

Steps Tank Owners Can Take

There are some preventive and corrective measures that tank owners can use to address lost or damaged certification labels:

Record the Label Information Early

• Tank owners should photograph and document all certification labels at the time of delivery and installation and maintain records and receipts that show who built the tank, when it was installed and who did the work.
• Keeping the labels clean and protected can extend their visibility over time.
• Protect labels from paint and other chemicals.

Use the STI Serial Number

If the tank is a welded steel tank built by an STI/SPFA Shop Fabricated Tank member it will have an STI serial number.  If the STI serial number is still legible or available in records, STI/SPFA can often help identify the tank’s original manufacturer, construction date, certification type, and shipping records. In some cases, installation information is also available if the relevant forms were submitted at the time.

Protect Labels During Installation

STI/SPFA’s installation guidelines recommend securing and protecting certification labels during setup to preserve this critical documentation.

Options When Labels Are Missing

If certification labels are no longer readable, and no records were kept, there are still options for verifying a tank’s condition and suitability for continued use:

Third-Party Inspection

A certified tank inspector can assess the tank to determine if it was constructed to a recognized standard and remains fit for service.  An experienced tank inspector should be able to determine the tanks original construction standard and help establish it suitability for continued service.

If necessary, the inspector can recommend or perform repairs to bring the tank back into compliance.

These inspection reports, when done by a certified tank inspector, are generally recognized by regulatory agencies and can help to verify the tank’s standard of construction and its suitability for continued service.  It is important that the AHJ’s expectations are satisfied by the report.

UL Field Evaluation

If an owner is confident that the tank originally carried a UL certification, then UL offers a field inspection service in which their inspectors examine the tank and issue an alternate listing indicating the tank meets UL standards. This does not replace the original UL label but may be accepted as a substitute in some jurisdictions.  This would not apply to tanks originally certified to other standards like SwRI or API.

Follow Recognized Standards

• STI/SPFA’s SP001 Standard for the Inspection of Aboveground Storage Tanks is widely used to guide inspections of shop-built tanks in service.
• API 653 Tank Inspection, Repair, Alteration, and Reconstruction may also be applicable if the tank is built to one of the API tank construction standards. These tanks are generally vertical, cylindrical steel single wall tanks. 

Consult Your AHJ

Before proceeding, tank owners should check with the Authority Having Jurisdiction (AHJ) to determine what documentation or inspections are required in the absence of the original labels.  Sometimes the AHJ will have records that can help establish the history of the tank. Requirements can vary by state or region.

Final Note: Labels Are Just the Beginning

A tank that is old enough to have lost its certification labels is often due—or overdue—for a formal inspection. Federal and state regulations require tanks to be inspected periodically (typically every 5 to 20 years, depending on the tank type and its installation). A missing or damaged label may be the first indicator of broader issues that need to be addressed to ensure environmental and operational safety.

Need Help?

If you have questions or need help identifying your tank using its serial number, contact STI/SPFA. We are here to support tank owners in maintaining safety, compliance, and service longevity.