ESP Survey Readiness for the Firm That Wants the Thickness Measurement Scope

Approval is a standing condition of the business, not a project deliverable

The enquiry for an ESP job arrives with a date attached. An owner has a renewal survey falling due, a yard slot booked and a superintendent assembling a team. The question asked of your firm is whether it is approved by that ship's society, and the answer is either yes today or no. There is no provisional route, no conditional acceptance pending audit, and no mechanism for a surveyor to take readings from an unapproved firm and regularise the position afterwards.

UR Z17 clause 4.2 states it without qualification: where the results of the service supplier are used by a surveyor in making decisions affecting classification, the supplier must be approved and verified by that society. Thickness measurement on ships and mobile offshore units is the first service named in the list. The only exceptions are non-ESP ships under 500 gross tonnage and all fishing vessels, which excludes precisely the vessels that never generate ESP work in the first place.

So readiness runs against the calendar, not against a job. Document review, an office audit and a witnessed demonstration consume months of elapsed time before a certificate exists, and each society runs its own process on its own schedule. The mechanics of that route are set out in our work on IACS service supplier approval. This page is about the survey itself, and about what an approved firm has to be able to do the moment it holds the certificate.

Which ships carry ESP work, and what the survey programme decides

The 2011 ESP Code, adopted as IMO Resolution A.1049(27), governs the enhanced programme of inspections during surveys of bulk carriers and oil tankers. Clause 7.2 is the sentence that creates your market: the thickness measurements should be carried out by a qualified company certified by an organization recognized by the Administration according to principles stated in Annex 5. Clause 7.1.1 adds that measurements not carried out by the recognized organization itself are witnessed by its surveyor, who is on board to the extent necessary to control the process.

Annex 5 is a compressed version of Z17 and worth reading against your own document pack. It asks for a company outline, the company's experience in thickness measurement of hull structures, technicians' careers with operators qualified to a recognised industrial NDT standard, the equipment used and its maintenance and calibration procedures, a guide for operators, training programmes, and the measurement record format. Then an audit. Then certification conditional on an on-board demonstration and satisfactory reporting, renewed at intervals not exceeding three years.

The survey programme itself belongs to the owner. It is submitted to class before the survey, identifies nominated corrosion-risk areas and sets the locations for close-up survey and thickness measurement, and the survey does not commence until it has been agreed. Your firm's exposure begins where that document sets the extent. The extent is not final, and the clause that unfixes it is the one most firms have never read.

The survey planning meeting your firm is required to attend

ESP Code clause 5.6.2 is explicit about who is in the room. Prior to commencement of any part of the renewal or intermediate survey, a survey planning meeting should be held between the attending surveyor or surveyors, the owner's representative in attendance, the thickness measurement company operator, and the master of the ship or an appropriately qualified representative appointed for the purpose. Clause 7.1.2 repeats the requirement from the thickness measurement side. Annex 14 clause 2.1 repeats it again, naming the thickness measurement firm's representative.

Annex 14 clause 2.3 is what turns attendance into an audit trail rather than a courtesy. The survey report should indicate where and when the meeting took place and who attended, naming the surveyor, the owner's representative and the thickness measurement firm's representative. Your firm's name and your attendee's name enter the class survey report. Send a technician who cannot speak to extent, acceptance criteria or escalation, and that is what the permanent record shows.

The indicative agenda in clause 5.6.3 runs to nine items and seven of them are yours: provisions and arrangements for thickness measurements covering access, cleaning and descaling, illumination, ventilation and personal safety; the extent of the thickness measurements; acceptance criteria against the list of minimum thicknesses; the extent of close-up survey and measurement given coating condition and suspect areas; execution of the measurements; taking representative readings where uneven corrosion, pitting or grooving is found; mapping of areas of substantial corrosion; and the communication route for findings.

Annex 14 clause 2.2 pins that last item down. Communication between the operator, the surveyor and the owner's representative is agreed at the meeting, covering reporting of measurements on a regular basis and prompt notification to the surveyor of excessive or extensive corrosion, pitting or grooving of any significance, structural defects such as buckling, fractures and deformed structures, detached or holed structure, and corrosion of welds. A firm with no written escalation route walks into that meeting with nothing to agree.

The surveyor directs the gauging, and your procedure has to expect it

Annex 14 clause 3.1 hands control of scope to the surveyor: the surveyor should decide the final extent and location of thickness measurements after the overall survey of representative spaces on board. Clause 3.3 goes to the individual reading: the surveyor should direct the gauging operation by selecting locations such that readings taken represent, on average, the condition of the structure for that area. The scope quoted against is a starting position, not a fixed deliverable.

Clause 3.2 covers the common commercial case where an owner wants gauging started before the overall survey. The surveyor advises that the planned extent and locations are subject to confirmation during the overall survey, and may require additional measurements based on findings. Clause 3.5 goes further still: where measurements indicate substantial corrosion or wastage in excess of allowable diminution, the surveyor directs locations for additional measurements to delineate the affected area and identify structural members for repair or renewal.

A firm that prices ESP work as a fixed count of readings absorbs the whole of that risk. A firm whose procedure, quotation and crewing plan anticipate delineation gauging, and whose supervisor can produce a mapped area within the same shift the surveyor asks for it, absorbs very little. Clause 3.6 adds the scheduling constraint that makes crewing awkward: measurements in areas where close-up surveys are required are carried out simultaneously with the close-up survey, so the gauging crew is tied to the staging plan rather than to its own.

The five things a Z17 thickness measurement procedure has to contain

Z17 Annex 1 clause 1.5 names the contents directly. Documented work procedures are at least to contain information on inspection preparation, selection and identification of test locations, surface preparation, protective coating preservation, calibration checks, and report preparation and content. Read that list against a generic UT thickness procedure and two items are missing outright: identification of test locations, and protective coating preservation.

Identification of test locations is the difference between a reading and a record. A number without a member, a frame position and a repeatable location cannot be compared against the original thickness, cannot be plotted against a diminution allowance, and cannot be found again by the surveyor who attends the next survey. Coating preservation is structural rather than cosmetic: gauging that strips a coating system inside a ballast tank creates the corrosion the survey exists to detect.

Clause 1.6 fixes the reporting basis by reference rather than by template. Reports are based on the guidelines given in UR Z7, Z7.1, Z7.2, Z10.1, Z10.2, Z10.3, Z10.4 and Z10.5 as relevant. Those are the hull survey requirements for the different ship types, and they carry the structural members to be measured and the diminution allowances that make a reading meaningful. A procedure that does not name the applicable Unified Requirement for the vessel alongside is a procedure an auditor will mark.

Reporting: the TM forms, the countersignature and the file that stays on board

The ESP Code does not leave report format to the firm. Annex 8 specifies the reporting forms for bulk carriers, TM1-BC through TM7-BC, with parallel sets for double-skin bulk carriers and for oil tankers, and states that they should be used for recording thickness measurements. The forms are organised by structural scope: all deck, bottom shell and side shell plating; shell and deck plating at one, two or three transverse sections; longitudinal members at those sections; cargo hold transverse bulkheads; and miscellaneous structural members.

Clause 7.3.1 sets the content. The report gives the location of measurements, the thickness measured and the corresponding original thickness, the date the measurements were carried out, the type of measuring equipment, the names of personnel and their qualifications, and is signed by the operator. Clause 7.3.2 closes the loop: the surveyor reviews the final thickness measurement report and countersigns the cover page. A report leaving the vessel without that countersignature is an incomplete survey record.

Clause 6.1.2 is why the report has a life far beyond the invoice. The survey report file, which includes the thickness measurement reports, is kept on board for the lifetime of the ship, and is also held in the owner's office and in the office of the Administration or the recognized organization. Work your firm signs this year is read by a surveyor a decade from now with the original thicknesses beside it. That is the standard the prescribed format exists to meet.

Operator files: Level 1 is the floor, and ship-structure knowledge is the gap

Z17 Annex 1 clause 1.3 places two requirements on the operator, not one. Certification to a recognised national or international industrial standard, with ISO 9712 Level 1 given as the example. And adequate knowledge of ship structures sufficient to elect a representative position for each measurement. The second requirement has no certificate behind it anywhere in the industry, which is exactly why it is the requirement firms cannot evidence when the auditor asks.

Clause 1.2 sets the responsible supervisor at ISO 9712 Level 2 or equivalent, and the general requirements add to both roles. Clause 5.2.2 requires a minimum of one year of tutored on-the-job training for operators, technicians and inspectors, with external training programmes acceptable where internal training is impossible. Clause 5.2.3 requires the responsible supervisor to hold a minimum of two years of experience as an operator within the activity for which the supplier is approved. Clause 5.2.4 defines the personnel record itself: age, formal education, training and experience for the services each person is approved for.

US firms run employer-based certification under SNT-TC-1A, and the level naming does not map cleanly onto the IACS examples. Which scheme and which level a given society accepts is a written question put to that society before a technician is assigned, and it is the substance of our page on UTM operator qualification for class approval. Ship-structure knowledge is evidenced separately, through a documented training module and a competency sign-off held in the same file.

Gauges, coatings, and the calibration record that reaches backwards

Z17 Annex 1 clause 1.4 is an equipment specification rather than a preference. On coated surfaces, instruments using the pulse-echo technique are required, either with an oscilloscope or as digital instruments using multiple echoes with a single-crystal technique. Single-echo instruments are permitted only on uncoated surfaces that have been cleaned and ground. A crew gauging a coated ballast tank with a single-echo instrument is working outside the approval its own firm holds.

Clause 5.2.5 sets the record around that equipment. The supplier keeps a record of the equipment used, available on request, containing information on maintenance and the results of calibration and verifications. The clause then adds the sentence that converts calibration from paperwork into commercial exposure: where the equipment is found not to conform to requirements, the society assesses and records the validity of previous measuring results, and takes appropriate action on the equipment affected.

That is retrospective by design. An out-of-tolerance gauge discovered during an audit puts every job that instrument produced since its last valid verification into question, on ships that sailed months ago. The control is per-instrument traceability: serial number printed on the report, verification records dated either side of the job, and calibration blocks carrying records of their own. It costs very little to build in advance and cannot be reconstructed afterwards.

Verification per job, and what the shared database sees

Z17 Annex 1 clause 1.7 is a single sentence with a large operational consequence. The supplier must have the surveyor's verification of each separate job, documented in the report by the attending surveyor's signature. Not a periodic sample, not a blanket approval covering a family of similar jobs. Each separate job. A report that leaves the vessel unsigned is not evidence that an approved service was performed at all.

Clause 8.2 lists the grounds on which approval is cancelled: the service improperly carried out or the results improperly reported; deficiencies found by a surveyor in the approved service operating system without appropriate corrective action; alterations to the quality system relevant to the certificate made without written notification; a missed intermediate audit where one was required; wilful acts or omissions; and deliberate misrepresentation. Clause 7.1 requires any alteration to the certified operating system to be reported immediately, with re-audit at the society's discretion.

IACS PR 23 makes the consequence portable between societies. Members report changes in the approval status of thickness measurement companies, including new approvals, expiry dates, suspensions and cancellations, and check that shared record before issuing or renewing a certificate. A suspension imposed by one society is visible to the next society your firm applies to. Approval is granted per society; the record of losing one is not confined to it.

What readiness work looks like inside your firm

The deliverables are specific and your firm owns all of them afterwards. A thickness measurement procedure written to Annex 1 clause 1.5 and referencing the correct UR Z7 and Z10 series for each vessel type. Personnel records carrying the four fields Z17 names, plus tutored on-the-job training evidence and a ship-structure competency record. An equipment register with per-instrument calibration and verification traceability. And report templates matching the ESP Code Annex 8 forms for the ship types you intend to work.

Around those sit the operational pieces that decide whether the first job goes well. A planning-meeting brief, so the person who attends can speak to extent, acceptance criteria and escalation without deferring. An escalation procedure that satisfies Annex 14 clause 2.2. And a rehearsal audit run against the same clause list a society auditor works from. Firms already carrying findings usually start with an NDT programme audit and gap assessment rather than with a rewrite.

This work sits alongside the wider maritime NDT consulting programme, and for firms whose ambitions run past gauging into weld NDT it sits alongside the written practice development a society reviews. Atlantis is affordable, accessible and fully customisable, and we scope readiness against your target societies and vessel types rather than against a generic checklist. Start the conversation, or request a demonstration, through contact.

Request a consultation