1. Separate environmental emission from onboard exposure
| Question | NEPTUNES/ESI-type work | Onboard noise survey |
|---|---|---|
| Receiver protected | Port/community environment outside the vessel. | Crew and other persons in onboard spaces. |
| Primary evidence | Airborne emission under a controlled moored operating condition, including total and frequency-dependent behaviour. | Noise exposure or accommodation/workspace levels at onboard receiver positions. |
| Operating state | Auxiliaries, HVAC, cargo systems, reefers, boiler, shore power and berth condition. | Specified navigation, machinery, load and space conditions. |
| Decision | Noise profile, port/environmental review or protocol submission. | Occupational, habitability, acceptance or troubleshooting assessment. |
2. Confirm the current protocol and recipient before mobilisation
The Port of Rotterdam states that an ESI Noise report is prepared according to the international NEPTUNES protocol, with the resulting score used by the ESI framework. IAPH reports that the ESI scheme and its administration continue to evolve. Obtain the current protocol, calculation tool, submission route and recipient requirements for the actual vessel and port before fixing the scope.
- Confirm whether the job is a protocol report, an engineering diagnosis or both.
- Identify the requested protocol edition and any port-specific instruction.
- Confirm who may perform, review, verify or upload the result.
- Do not promise an ESI score, port incentive or acceptance before review.
3. Freeze the moored operating-condition matrix
| Record | Evidence | Why it matters |
|---|---|---|
| Electrical generation | Auxiliary engine identity, load, exhaust/silencer state and shore-power status. | Generator/exhaust components often control low-frequency emission. |
| Ventilation and HVAC | Fans, dampers, louvers, duty/standby state and spaces served. | Large openings and fans can be dominant sources. |
| Cargo and hotel load | Cranes, pumps, cargo ventilation, reefers, galleys and passenger services. | A quiet test state may not represent the intended port call. |
| Berth environment | Adjacent vessels, cranes, vehicles, industry, water, barriers and reflecting façades. | Background and reflections can contaminate or bias results. |
| Weather | Wind speed/direction, precipitation, temperature and other required observations. | Weather affects propagation and measurement validity. |
4. Make measurement geometry reproducible
Record vessel reference points, waterline/freeboard, source heights, microphone coordinates and height, horizontal distances, quay edge, barriers and major reflecting surfaces. Photograph each position and mark it on the berth/vessel plan. Apply only the distances and corrections required by the current agreed protocol; do not substitute a convenient quay position without documenting the limitation.
ISO 2922:2020 addresses reproducible airborne-sound measurements from vessels in inland waterways, ports and harbours and refers results to a defined reference distance. It can inform the measurement framework when contractually selected, but it does not replace the current NEPTUNES/ESI protocol.
5. Retain the evidence behind the reported value
- Calibrated Class 1 measurement chain and field calibration before/after attendance.
- Declared time weighting, averaging interval, total level and frequency-band data required by the protocol.
- Time histories and audio/observational notes where permitted, to identify contamination and intermittent events.
- Background measurements or defensible background treatment when the vessel source cannot be isolated.
- Weather, operating-state and geometry evidence tied to every valid measurement interval.
Low-frequency and tonal characteristics may drive port-community disturbance even when a single broadband A-weighted result appears moderate. Retain the spectrum and observation record required to support the protocol calculation and engineering diagnosis.
6. Keep protocol scoring and source diagnosis distinct
| Observed feature | Focused diagnostic check | Possible action route |
|---|---|---|
| Strong low-frequency component | Auxiliary engine order/exhaust, fan blade-pass behaviour, structural panel radiation and operating load. | Silencer, resilient mounting, operating strategy or structural treatment review. |
| Prominent tone | Narrowband evidence, candidate rotating equipment and on/off or load comparison where permitted. | Treat the confirmed source rather than the overall level blindly. |
| Quay level varies sharply | Intermittent port sources, cargo cycles, adjacent vessel and reflection geometry. | Repeat controlled intervals or record exclusions/limitations. |
| One louver or opening dominates | Near-source diagnostic measurements and plant state. | Attenuator, fan, duct, grille or duty configuration investigation. |
Near-source measurements help locate causes but should not be substituted for protocol receiver data unless the governing method explicitly permits it.
7. Build a traceable NEPTUNES/ESI data package
- Vessel identity, port/berth, date/time and survey purpose.
- Applicable protocol edition, calculation basis and submission recipient.
- Vessel, machinery, cargo, hotel-load and shore-power condition.
- Berth plan, geometry, photographs, weather and background sources.
- Instrumentation, serial numbers, calibration and field-check records.
- Raw/processed results, frequency data, exclusions and calculation trail.
- Noise-profile/score output where authorised and applicable.
- Limitations, corrective priorities and exact retest condition.
8. Port, class and flag context
ESI participation, a port incentive, environmental reporting and a class/flag requirement are separate decisions. For ABS-, BV-, CCS-, CRS-, DNV-, IRS-, KR-, LR-, ClassNK-, PRS-, RINA- or Türk Loydu-classed vessels and relevant flags, confirm whether the report is requested by a port, owner, charterer, contract, notation or attending surveyor. This guide makes no supplier-approval, score or acceptance claim.
Authoritative references
- IAPH Environmental Ship Index — current scheme and administration context.
- Port of Rotterdam: ESI Noise and NEPTUNES reporting.
- ISO 2922:2020 — airborne sound emitted by vessels in waterways and harbours.
9. What to send for feasibility review
- Vessel name/IMO number, type and principal dimensions.
- Port, berth, side alongside, access and attendance window.
- Current protocol/recipient instruction and required submission date.
- Moored machinery, cargo and hotel-load configuration.
- GA plan, source locations and known port-noise complaints.
Attendance can be assessed in Singapore, Malaysia, India, Sri Lanka, Indonesia, Thailand, the Philippines, the Middle East, Asia-Pacific and worldwide, subject to access, protocol suitability and availability.