API St 653-2014 (2025) PDF

Full title and description

API STD 653:2014 — Tank Inspection, Repair, Alteration, and Reconstruction (Fifth Edition, November 2014), amended through Addendum 4 (2025). This standard establishes minimum requirements and recommended practices for the in‑service inspection, maintenance, repair, alteration, relocation, and reconstruction of welded steel aboveground storage tanks (primarily those constructed to API 650 and its predecessor API 12C).

Abstract

API 653 provides procedures and acceptance criteria to preserve or restore the structural integrity of aboveground steel storage tanks after they have been placed in service. The document addresses inspection methods, fitness‑for‑service evaluation concepts, repair and alteration practices, welding and examination requirements, testing, marking, and recordkeeping. Addenda and errata published since 2014 (including Addendum 1:2018, Addendum 2:2020, Addendum 3:2023, Errata updates and Addendum 4:2025) update normative references and clarify technical methods such as bottom‑plate evaluation and inspection techniques.

General information

• Status: Current / Active (Fifth Edition, 2014, with subsequent addenda through Addendum 4:2025).
• Publication date: Fifth Edition published November 2014; Addendum 4 published 01 July 2025 (amendments and errata issued in intervening years including 2018, 2020, 2023 and errata updates to 2025).
• Publisher: American Petroleum Institute (API).
• ICS / categories: Petroleum and related technologies — Equipment and handling of petroleum products and storage (ICS: 75 — Petroleum and related technologies; relevant subareas for storage tanks and handling equipment).
• Edition / version: Fifth Edition (2014) with Addendum 1 (2018), Addendum 2 (2020), Addendum 3 (2023), Errata updates and Addendum 4 (2025).
• Number of pages: Base standard (Fifth Edition, 2014) approximately 198 pages; addenda are published as short amendments (Addendum 4 published as a separate addendum). (Publishers and distributors may show slight variation in packaged page counts depending on included addenda.)

Scope

API 653 applies to in‑service welded steel aboveground storage tanks (generally tanks originally constructed to API 650 or API 12C). The scope covers tank foundation, bottom, shell, structure, roof, attached appurtenances, and nozzles to the face of the first flange, first threaded joint, or first welding‑end connection. The standard is intended to provide minimum requirements for inspection frequency, condition assessment, repair, alteration, relocation and reconstruction but allows application of API 650 design, welding and material requirements where appropriate. Fitness‑for‑service assessment procedures (e.g., API 579‑1/ASME FFS‑1) are referenced where detailed evaluation methods are required.

Key topics and requirements

• Inspection intervals and inspection program planning for in‑service tanks, including visual, ultrasonic and other NDT methods.
• Assessment and acceptance criteria for corrosion, metal loss, pitting and mechanical damage; use of fitness‑for‑service concepts where applicable.
• Repair and alteration procedures, including structural strengthening, plate replacement, nozzles, roof repairs, and reconstruction practices.
• Welding, examination and testing requirements for repairs and alterations (qualification, NDT methods, post‑repair pressure testing, marking and recordkeeping).
• Guidance and updates on tank bottom evaluation techniques — clarifications (in Addendum 4:2025) on Magnetic Flux Leakage (MFL) and Ultrasonic Testing (UT) use for soil‑side corrosion assessment, and a new/updated normative reference set (including API RP 575 referenced in recent amendments).

Typical use and users

API 653 is used by tank owner/operators, inspection and maintenance engineers, third‑party inspection agencies, repair contractors, welding specialists, regulatory agencies and consultants responsible for storage tank integrity and safety. It is commonly referenced in maintenance programs, regulatory compliance, inspection certification (including API 653 inspector certification programs) and fitness‑for‑service evaluations.

Related standards

Key related documents often cited or used alongside API 653 include: API 650 (Welded Tanks for Oil Storage), API RP 575 (Inspection Practices for Atmospheric and Low‑Pressure Storage Tanks), API RP 571 (damage mechanisms), API RP 576 (valve inspection), API RP 651 (cathodic protection), API RP 652 (tank bottom corrosion considerations), API 579‑1/ASME FFS‑1 (fitness‑for‑service), and relevant ASME BPVC sections for welding/examination. Recent addenda to API 653 also reference updated RP documents.

Keywords

API 653; tank inspection; storage tanks; repair; alteration; reconstruction; in‑service inspection; API 650; MFL; ultrasonic testing; fitness‑for‑service; tank bottom; aboveground storage tanks; API addendum 2025.

FAQ

Q: What is this standard?

A: API 653 is the American Petroleum Institute standard that sets minimum requirements and recommended practices for the inspection, evaluation, repair, alteration, and reconstruction of in‑service welded aboveground storage tanks (primarily tanks built to API 650). It is the primary industry guidance for maintaining tank structural integrity after commissioning.

Q: What does it cover?

A: It covers inspection planning and intervals, NDT and examination methods, evaluation and acceptance criteria for degradation (corrosion, pitting, mechanical damage), repair and alteration procedures, welding and testing requirements, marking, and recordkeeping. The scope limits coverage to tank foundation, bottom, shell, roof, attached appurtenances and nozzles to the first flange/joint/connection. Recent addenda refine specific inspection and measurement practices.

Q: Who typically uses it?

A: Tank owner/operators, inspection companies, maintenance and integrity engineers, repair contractors, welding examiners, regulators and consultants use API 653 to design inspection programs, evaluate tank condition, and implement repairs and alterations. API also runs an API 653 inspector certification program tied to the standard.

Q: Is it current or superseded?

A: The Fifth Edition (2014) remains the base edition, but it has been kept current by successive addenda and errata; Addendum 4 (2025) is the latest published amendment. Users should apply the base 2014 document together with the applicable addenda/errata in effect at the time of use.

Q: Is it part of a series?

A: Yes — API 653 is part of API’s family of storage‑tank and fixed‑equipment standards and recommended practices that includes API 650 (tank construction), API RP 575/576/571/651/652 and related documents covering inspection, corrosion, cathodic protection, valves, damage mechanisms and fitness‑for‑service. These documents are commonly used together for tank design, operation and integrity management.

Q: What are the key keywords?

A: Tank inspection, storage tank repair, API 653, in‑service inspection, tank alteration, tank reconstruction, aboveground storage tank, API 650, MFL, ultrasonic testing, fitness‑for‑service.