Separate habitability evaluation from structural diagnosis before attendance.
A cabin, mess room, office, control station or passenger space can be measured to evaluate vibration experienced by people. A deck, superstructure, foundation or hull response can be measured to understand structural behaviour and propulsion-related excitation. The same accelerometer may appear in both scopes, but the point selection, axes, frequency treatment, operating sequence and conclusion are not interchangeable.
Use the current ISO 20283-5 and ISO 6954 ship-habitability guide when the governing-document question concerns occupied-space evaluation. Use structural and hull vibration measurement when the buyer needs a source-path-receiver investigation, global response picture or response-to-propulsion relationship. Record the decision owner and the document, edition, contract clause or class/flag instruction they require.
| Scope ID | Question to decide | Receiver / structure | Governing basis | Decision owner | Witness need | Excluded conclusion |
|---|---|---|---|---|---|---|
| SCP-___ | ___ | ___ | ___ | ___ | ___ | ___ |
| SCP-___ | ___ | ___ | ___ | ___ | ___ | ___ |
Agree what each witness will observe and sign.
List the vessel representative, owner or manager, yard, designer, maker, attending surveyor and measurement team only when they are genuinely involved. Before testing, state whether each witness will confirm room availability, point location, machinery lineup, draught, speed or RPM, load, instrument check, run start and stop, deviation, preliminary result or report receipt. A person who was not present should not be shown as a test witness.
Witnessing and acceptance are different acts. An attending surveyor may observe the measurement while a separate technical office reviews the report. A master or chief engineer may confirm the operating condition without accepting a structural interpretation. The record should preserve those boundaries instead of using a generic signature box.
| Witness / role | Organisation | Observed step | Authority boundary | Required record | Signature / time | Comments |
|---|---|---|---|---|---|---|
| WIT-01 | ___ | ___ | ___ | ___ | ___ | ___ |
| WIT-02 | ___ | ___ | ___ | ___ | ___ | ___ |
| WIT-03 | ___ | ___ | ___ | ___ | ___ | ___ |
Define a valid run before the vessel reaches the test condition.
Habitability and structural response may change with propulsion speed, propeller condition, engine load, generator combination, thruster use, sea state, heading, water depth, draught, trim, tank condition and nearby machinery. Agree the steady hold, permitted tolerance, minimum useful duration and repetition rule. Where controlled speed sweeps are needed, agree safe increments and stop conditions with the authorised vessel team.
Do not silently average an invalid hold into a result. If RPM drifted, a thruster started, a door slammed, the sea condition changed or a channel overloaded, retain the event and state whether the run is rejected, qualified or used only for diagnosis. This makes the result more credible than a table that hides inconvenient conditions.
| Run ID | RPM / speed / load | Vessel and machinery state | Environmental state | Hold / duration | Valid / qualified / rejected | Witness time |
|---|---|---|---|---|---|---|
| RUN-01 | ___ | ___ | ___ | ___ | ___ | ___ |
| RUN-02 | ___ | ___ | ___ | ___ | ___ | ___ |
| RUN-03 | ___ | ___ | ___ | ___ | ___ | ___ |
Keep every result connected to its physical point and acquisition setup.
Assign one stable identifier to each occupied-space receiver or structural point. Record location, deck or frame reference, mounting surface, axis, sensor, attachment, sensitivity, cable and analyser channel. Then record the measurement quantity, units, amplitude convention, frequency range, weighting, window, resolution, averaging and record duration. Photographs and marked drawings should use the same identifiers as the data files and report tables.
For habitability work, the reported frequency-weighted overall value should remain distinguishable from unweighted spectra used for diagnosis. For structural work, displacement, velocity and acceleration should not be merged under the word “level”. When a tachometer, phase reference or process channel is used, its clock and identifier should travel with the vibration channels.
| Point ID | Location / frame | Axis | Sensor / attachment | Channel / file tag | Quantity / processing | Photo / drawing |
|---|---|---|---|---|---|---|
| CH-01 | ___ | ___ | ___ | ___ | ___ | ___ |
| CH-02 | ___ | ___ | ___ | ___ | ___ | ___ |
| CH-03 | ___ | ___ | ___ | ___ | ___ | ___ |
Specify usable deliverables rather than asking vaguely for “all data”.
The handover scope should say whether the recipient receives native analyser files, open-format time histories, spectra, order or phase data, tachometer records, run logs, point photographs, marked plans, calibration evidence and processing notes. Native files can preserve metadata but may require proprietary software. Open exports improve accessibility but can lose settings or precision. When both are required, state the expected folder structure and naming convention before the survey.
Record file checksums or another controlled transfer record where contractual or technical review requires assurance that the handed-over files match the retained set. State retention period, access restrictions, personal or vessel-sensitive information, and whether the owner permits anonymised technical publication. Absence of publication permission means the data stay confidential.
| Deliverable | Format / version | Run / channel coverage | Naming rule | Recipient | Transfer check | Retention / restriction |
|---|---|---|---|---|---|---|
| Native data | ___ | ___ | ___ | ___ | ___ | ___ |
| Open export | ___ | ___ | ___ | ___ | ___ | ___ |
| Plots and tables | ___ | ___ | ___ | ___ | ___ | ___ |
| Logs and drawings | ___ | ___ | ___ | ___ | ___ | ___ |
Give a reviewer enough information to reproduce the reasoning.
A useful technical review checks the scope, document applicability, point plan, operating conditions, instrument traceability, processing, invalid-run decisions, calculations and wording of the conclusion. It should also test whether an occupied-space result has been stretched into an unsupported machinery or structural diagnosis, or whether a structural correlation has been described as proof of causation.
Record the reviewer's competence and the exact revision reviewed. Preserve comments, responses and unresolved limitations. Do not name a class society, flag, customer, yard, designer or external specialist as a reviewer unless the review actually occurred and publication is permitted. A blank review route is evidence of a controlled process, not an endorsement.
| Review ID | Reviewer competence | Report / data revision | Comment | Response / change | Open limitation | Closure evidence |
|---|---|---|---|---|---|---|
| REV-01 | ___ | ___ | ___ | ___ | ___ | ___ |
| REV-02 | ___ | ___ | ___ | ___ | ___ | ___ |
This page contains no completed vessel result, customer identity, surveyor acceptance, external review, class approval, flag authorisation, pass statement, backlink or testimonial.
Keep changed conditions visible when comparing before and after work.
A matched retest should repeat the decision-relevant points, axes, sensors or equivalent setup, frequency treatment, RPM or speed, load, vessel state and machinery lineup. If draught, trim, sea state, propeller condition, mounting or processing changed, show the difference beside the comparison. A percentage reduction without comparable conditions can misstate performance.
Where exact repetition is impossible, identify which conclusion remains supported. A post-repair cabin reading may show lower weighted acceleration at one operating point while leaving the wider speed range untested. A structural peak may move with loading condition without proving that a stiffening action caused the change. The report should state measured change, interpretation, confidence and remaining alternatives separately.
| Item | Baseline condition | Retest condition | Difference | Effect on comparison | Decision retained | Further action |
|---|---|---|---|---|---|---|
| Point / axis | ___ | ___ | ___ | ___ | ___ | ___ |
| Operating state | ___ | ___ | ___ | ___ | ___ | ___ |
| Acquisition / processing | ___ | ___ | ___ | ___ | ___ | ___ |
Release a traceable result with a clear acceptance boundary.
- Identify the vessel condition, scope, applicable document and requested decision.
- Connect every reported value to a point, axis, channel, run and processing basis.
- Separate frequency-weighted habitability evaluation from diagnostic spectra.
- Separate measured structural response, correlation and inferred source mechanism.
- List rejected, qualified and unavailable operating runs.
- State uncertainty or measurement limitations where they affect a near-limit decision.
- Attach or reference the agreed data handover and witness records.
- Name the authorised acceptance owner; do not imply universal class or flag acceptance.
| Report / revision | Scope complete | Run evidence complete | Data handed over | Review closed | Open limitation | Release owner |
|---|---|---|---|---|---|---|
| RPT-___ | ___ | ___ | ___ | ___ | ___ | ___ |
Confirm the controlling edition for the actual vessel and decision.
- ISO 20283-5:2016 addresses measurement, evaluation and reporting of vibration with regard to habitability on passenger and merchant ships.
- ISO 20283-2:2008 addresses measurement, diagnostic evaluation and reporting of ship structural vibration excited by propulsion machinery.
- ISO 2631-1:1997 provides general requirements for evaluating human exposure to whole-body vibration, including low-frequency motion considerations outside the normal habitability scope.
Official records establish document identity and broad scope. The vessel contract, applicable class rules, flag instructions, notation, project specification and competent review process control the actual acceptance route. IACS does not approve suppliers, and this resource claims no class, flag or maker authorisation.
Agree the witness and handover record before attendance.
Send the affected spaces or structures, vessel particulars, operating matrix, governing documents, witness roles and required data formats so the measurement and reporting chain can be scoped.
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