Tank inspection software for API 653 inspection contractors

The tank register is the spine, not the report

Every API 653 calculation reads from construction data that does not change: diameter, height, number and thickness of shell courses, original construction standard, bottom design, whether a release prevention barrier is present, the product stored and its specific gravity, and the joint efficiency assumed. That data set is entered once and used for the next thirty years. Most contractors re-key it every inspection cycle from a scanned copy of the previous report.

Re-keying is where the errors enter. A course thickness transposed, a specific gravity carried over from a different product, a release prevention barrier assumed rather than verified. The last one is expensive, because the 30-year internal ceiling depends on the barrier existing, and claiming it on a tank without one produces an interval that cannot be defended when the owner or their insurer asks. The register must carry the source of each construction value.

A register is what lets an owner, or an integrity contractor working for one, plan a fleet: which tanks come due, which are trending steeper than the last cycle assumed, which are approaching a minimum thickness. That planning lives in the owner's integrity system or the inspector's own register, not in Atlantis ERP. What the contractor controls is whether each cycle's readings arrive complete enough to keep it honest. API 653 tank inspector services describes the delivery side of the same programme.

Interval arithmetic: RCA, N, and the divisor that changes

API 653 does not give one interval formula. It gives one pair of quantities used three ways. RCA is the remaining corrosion allowance in mils, measured thickness minus minimum required thickness. N is the corrosion rate in mils per year. External visual divides by 4N and caps at 5 years. External ultrasonic thickness measurement divides by 2N and caps at 15 years, or 5 years where the corrosion rate is not known. Internal divides by N.

The internal interval carries additional structure. Under the corrosion rate method the first interval does not exceed 10 years unless Table 6.1 safeguard credits apply, covering thicker bottom plate, thin-film or thick lining, cathodic protection, a release prevention barrier and alternative bottom materials. The credits are additive, so a lined tank with cathodic protection accumulates both. Section 6.4 caps the result at 20 years, or 30 years with a release prevention barrier.

Section 6.4.3 opens the risk-based route under API RP 580, setting the interval from likelihood and consequence rather than from corrosion rate alone. Whichever route is used, the record has to carry the inputs and the route, not just the answer: RCA, N, the divisor, the credits claimed and the minimum remaining thickness computed under Section 4.4.5. That calculation belongs to the API 653 inspector. Atlantis ERP does not perform it; the UT thickness and MFL reports it produces carry the readings, the instrument and the technician the calculation depends on. See the API 653 tank inspection guide.

MFL bottom coverage is a claim you must defend plate by plate

Magnetic flux leakage is how the bottom gets scanned, and coverage is the number the owner cares about. API 653 requires the bottom to be examined; the method, the extent, the lane spacing and the percentage of each plate scanned come from the inspection plan agreed with the owner. Coverage is therefore a contractual commitment rather than a code number, which means your record has to evidence what was achieved, plate by plate.

A defensible MFL record carries a bottom plate map with each plate identified, the coverage achieved on that plate, the scan direction, the equipment and its calibration status on the day, the sensitivity verification against the reference plate, and every indication plotted to a position on the map. Indications carried forward then link to the prove-up ultrasonic reading that sized them, and from there to the disposition and any repair.

Field conditions make this harder than it sounds. Sludge, obstructions, annular ring proximity and appurtenances create areas the scanner cannot reach, and those are precisely the areas a leak later appears in. Recording exclusions explicitly, with reason and area, protects the contractor and tells the owner what was not covered. Offline field capture inside a tank, where there is no signal at all, is a hard requirement for capturing this at source.

Settlement survey data has to trend across cycles

API 653 Annex B evaluates tank bottom settlement: planar tilt, out-of-plane settlement of the shell, edge settlement, and localised bottom depressions. The out-of-plane evaluation fits a cosine curve to elevation readings taken at points around the shell circumference and measures each point deviation from that fitted curve against an allowable. The arithmetic is unforgiving of missing points, because the fit degrades with every gap in the series.

The problem contractors create for themselves is storing the conclusion and discarding the inputs. Next cycle, a different crew takes elevations at a different number of points, at different positions, against a different datum, and the two surveys cannot be compared at all. Settlement is a trend phenomenon. A single survey says the tank is within allowable today; only a series says whether it is moving, in which direction, and how fast.

So the record has to fix the measurement geometry: point count, point identifiers, angular positions, datum, and instrument, alongside the elevations themselves. The next crew then measures the same points, and whoever evaluates settlement can trend the two surveys without reconciling them by hand. Atlantis ERP does not evaluate settlement under Annex B; it keeps the survey file with the job and the report, so it is there next cycle.

Thickness history per course, per measurement location

Shell thickness is not one number per tank. It is a reading per condition monitoring location per course, and the value of the dataset lies entirely in its history. Short-term corrosion rate comes from the last two surveys; long-term rate comes from original thickness to current. API 653 uses both, and the governing rate drives the interval and the remaining life calculation the owner relies on for budgeting.

That arithmetic requires every historical reading to survive at the location level. Contractors storing only the current survey, because the previous one arrived as a PDF from a different contractor, cannot compute a long-term rate at all and default to conservative assumptions that shorten intervals and cost the owner money. Preserving prior readings is therefore a commercial argument as much as a technical one, and it wins bids.

Each reading also needs its provenance: date, instrument and serial number, calibration status, technician and their certification, procedure revision, and surface condition. That is what lets a reading be defended when it disagrees with the previous cycle by an implausible amount. In Atlantis ERP the instrument's calibration records and the technician's certificates sit in the same system as the report, so neither has to be retyped. The short-term and long-term rates themselves are calculated by the inspector or the owner's integrity system, not by the ERP.

What API 653 Section 6.9 requires the report to carry

Section 6.8 covers records and Section 6.9 covers reports, and the distinction matters. Records are the permanent file held for the life of the tank. The report is the document issued to the owner, and it must contain enough for a third party to reproduce the inspection: what was examined, by which method and procedure revision, with which equipment, by whom, and what was found and where.

Beyond findings, the report carries the analysis: thickness data with short-term and long-term corrosion rates, minimum required thickness calculations, remaining life, settlement evaluation against Annex B, the next inspection due dates with the arithmetic behind them, and recommended repairs or alterations. The API 653 inspector identity and certification number appear on it, because the certification is what gives the determination its standing with the owner and the regulator.

Issuing reports from a system rather than a loose template has a second benefit: the readings exist as data, not only as a PDF, and owners increasingly want them loaded into their own integrity systems. Atlantis reports go out as PDF or on your own Excel template, and approved reports can be shared through the client portal for inspection reports, which removes a recurring source of post-delivery email traffic.

Breakout tanks are held to a different API 653 edition

A US tank inspection contractor works two populations that look identical and are regulated differently. Non-jurisdictional tanks are inspected to whichever edition of API 653 the owner specifies, typically the current one. In-service atmospheric and low-pressure steel above-ground breakout tanks on hazardous liquid pipeline systems fall under 49 CFR 195.432, which incorporates API Std 653 by reference at a fixed edition that changes only by rulemaking.

That fixed edition is currently the 3rd edition, issued December 2001. PHMSA published a notice of proposed rulemaking on 2 June 2026 proposing to move the incorporation to the 5th edition of November 2014, to authorise risk-based inspection procedures for setting breakout tank intervals, and to allow a maximum of 20 years for an initial internal inspection and 25 years for subsequent inspections supported by RBI analysis. The notice set a comment deadline of 3 August 2026.

The software consequence is immediate and easy to miss: the governing standard edition belongs on the inspection record as a field. A contractor whose report template hard-codes one edition will misstate the basis on half its work, and an interval computed under one edition rules cannot be silently carried into the other. Stamp the edition, the jurisdiction and the interval route onto every tank inspection when it is created.

What Atlantis ERP does for tank inspection records

Atlantis ERP is the contractor's system, not the tank owner's. On an API 653 job it holds the work that produces the reports: the job and its client references, the crew and the instruments assigned to it, and the reports themselves. MFL floor scans are recorded as MFL reports with the scan mode and item lines; shell and nozzle readings as UT thickness reports with readings recorded by direction; visual findings as VT reports with photos. Each report moves through draft, in progress, review, approved and sent, with inspector, reviewer and approver signatures, and the authorized inspector's name and signature where the client requires it.

Behind each report sit the records an owner or auditor asks about next. Technician certificates are held by scheme, level and method with vision tests, their status is worked out automatically, and warnings are raised before anything expires. Instruments and probes are tracked by serial number with calibration certificates and due dates; double-booking of a technician or an instrument is blocked, and the dispatcher is warned if an out-of-calibration instrument is assigned. The field app works inside the tank with no signal and syncs when the crew comes out. See the NDT Reports app.

The same system is set up for other industries too: pipeline inspection software for US NDT contractors, refinery and petrochemical inspection software and aerospace NDT software for Nadcap suppliers.

What Atlantis ERP does not do on API 653 work

It does not calculate API 653 inspection intervals, remaining corrosion allowance, corrosion rates or remaining life. It does not evaluate settlement under Annex B, run risk-based inspection under API RP 580 or API RP 581, or perform fitness-for-service assessments under API 579-1. It is not a tank register for an owner's fleet. Those calculations belong to the API 653 inspector and the owner's integrity system; what Atlantis gives them is a complete, signed, traceable set of readings to calculate from, which is the part a contractor is paid to deliver.

If a tender asks the contractor to deliver next-due dates, compute them in the inspector's own calculation and issue them with the report package; do not expect the ERP to produce them. If you need software that holds the register and computes intervals across a fleet, you are evaluating an integrity management system, a different category explained in our guide to NDT inspection software.

Selecting inspection software for API 653 work

Start by deciding which side of the line you are buying for. An integrity management system holds the owner's tank register and computes intervals; NDT inspection software runs the contractor's work and produces the readings and reports those systems consume. Most contractors need the second, and many of their owners already run the first.

Then score the contractor side on evidence. Assign a technician whose certificate has expired to a tank job; issue an instrument that is past its calibration date; complete an MFL report inside a tank with the device offline; return a report for correction and approve the revision. Each of those either works on the day or it does not, and a feature list will not tell you which.

Atlantis ERP is configured for each company, with the offline field app, certificate and calibration records, crew assignments, method-specific reports, and quotations, timesheets and invoicing on the same job. Affordable, accessible, fully customizable. Start a free trial, or book a guided walkthrough and bring one tank file and one owner specification.

Questions tank inspection contractors ask

Does API 653 specify an MFL coverage percentage? No. API 653 requires the bottom to be examined and leaves the method, extent and coverage to the inspection plan agreed between the owner and the contractor. Coverage is a contractual commitment, so the record has to evidence what was achieved plate by plate, including the areas that could not be scanned and the reason each area was excluded.

How is minimum remaining thickness determined for a tank bottom? Under Section 4.4.5, with the bottom minimum depending on whether there is a means of detecting and containing a leak. A bottom with no such means is held to a higher minimum than one with a release prevention barrier or equivalent. The register therefore has to record which case each tank falls into, verified against construction records rather than assumed.

Can an internal inspection interval exceed 20 years? Yes, to 30 years with a release prevention barrier under the corrosion rate method. Section 6.4.3 also permits a risk-based inspection assessment under API RP 580, setting the interval from likelihood and consequence. Whichever route applies, the record must name the route and hold the inputs, because the next inspector updates the calculation rather than repeating the whole assessment.

What data should be handed to the tank owner alongside the report? Thickness readings by condition monitoring location and course, settlement elevations by point identifier, the MFL plate map with coverage and indications, short-term and long-term corrosion rates, and the interval inputs. Owners load these into their own integrity systems. Handing over only a PDF guarantees the next cycle starts by re-keying work you have already done.

Does Atlantis ERP hold a tank register or calculate API 653 intervals? No. Atlantis ERP does not calculate intervals, remaining corrosion allowance, corrosion rates or remaining life, and it does not hold an owner's tank register. It records the UT thickness, MFL and visual reports, the technicians and instruments behind them, and the review and approval that release them. The API 653 inspector or the owner's integrity system does the calculation from those records. Start a free trial or book a walkthrough to see it on your own tank file.

Is there API 653 software that calculates inspection intervals? Yes, but it is a different category: calculation and report-builder tools, and owner-side RBI systems such as those built on API RP 580 and API RP 581. Atlantis ERP does not calculate intervals, remaining corrosion allowance or remaining life; it holds the signed readings those calculations use.

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