An API 653 tank inspection reporting workflow should make the condition, inspection history, evaluation basis, repairs, and final disposition of an in-service aboveground storage tank traceable from inspection scope through final review. The record should connect tank identity, shell, roof, bottom, annular ring, foundation, nozzles and appurtenances, thickness measurements, settlement data where applicable, NDE results, drawings, photographs, repair/alteration records, and inspector/engineering review. The software can organize the record and perform assisted or automated calculations from entered inputs while the authorized inspector and responsible engineering or owner/user personnel remain responsible for interpretation and disposition. It supports the inspection and reporting workflow; it does not replace the API 653 Authorized Inspector, owner/operator inspection program, or engineering review required to determine suitability for continued service.
1. Define the tank and inspection scope
Set up the tank number, service, diameter or other design/construction information available to the inspection team, inspection date, prior inspection reference and scope. Separate the shell courses, roof, bottom, annular plates, appurtenances, nozzles, manways, welds, tank foundation and other areas covered by the inspection plan. Identify whether the work includes visual inspection, internal or external examination, thickness measurement, settlement survey, NDE, repairs or a focused evaluation.
Use a drawing and stable location convention for every measurement. A shell point can reference course, orientation, elevation or weld; a bottom point can reference a grid, plate, radial distance or drawing coordinate. SketchMapp inspection drawing and CML mapping can help connect tank geometry, CML/TML points, findings and report-ready field references.
2. Capture shell, roof and bottom data
Record thickness readings with the component, course or plate, point identifier, measurement date, method, units, nominal or reference thickness and any relevant access or surface condition. Preserve the measurement grid or point map so a later inspection can return to the same locations. For roof and bottom work, retain the relationship between the reading and the plate, weld, sump, annular area or other physical reference.
Photos should show the tank, access, coating, corrosion, pitting, settlement indicators, welds, appurtenances and any limitation that affects interpretation. Attach inspection notes, NDE reports, technique sheets, settlement survey records and repair evidence to the same tank record. Review duplicate identifiers, missing points, changed locations and mixed units before creating trends.
3. Trend CML/TML history and record evaluation inputs
Compare current and prior measurements only when the locations and measurement basis are sufficiently comparable. Retain the source readings, dates, and calculation basis used for corrosion rate, remaining corrosion allowance, minimum required thickness, and inspection-interval decisions. Where settlement evaluation is included in the inspection scope, preserve the survey points, reference system, datum, field measurements, evaluation method, and assumptions used in the analysis.
Tank evaluation may also require review of shell thinning, pitting, roof condition, bottom and annular-plate thickness, settlement, distortions, welds, nozzles, or repair history. Automated calculations can organize and surface these results, but the applicable API 653 requirements, owner/operator procedure, and qualified inspection/engineering review control the final disposition.
4. Compile the API 653 inspection package
Assemble the cover and scope, tank description, inspection personnel, shell/roof/bottom thickness tables, CML/TML drawings, corrosion-rate and remaining-corrosion-allowance results, settlement data and evaluation where applicable, photos, NDE reports, repair or alteration records, findings, disposition, recommendations where applicable, and required review/signature fields. Check that the tank number, point identifiers, dates, units and drawing references remain consistent across the report.
The API/NDE reporting workflow connects tank inspection data, calculations, drawings, photos, checklists and report compilation. It supports a documented workflow; it does not determine tank suitability, approve a tank for service or replace qualified engineering judgment.
Questions inspectors ask
Should shell, roof and bottom points share one numbering system?
They need a consistent convention, but component-specific prefixes or location fields can make the physical reference clearer and reduce ambiguous point names.
Does a tank calculation approve the tank for service?
No. A calculated result is an evaluation input. Suitability, repairs, operating limits and service decisions require review under the applicable code and owner-user process.
What should accompany a settlement input?
Retain the survey date, point locations, reference datum, measurement units, field conditions, survey method, raw measurements, evaluation method, assumptions, and the qualified review of whether the observed settlement is acceptable under the applicable API 653 criteria.