1. Start with the decision, not a fixed parameter list
“The air feels stuffy” can describe inadequate outdoor air, high occupancy, heat, humidity, odour transfer, particulate ingress or an intermittent source. Before sampling, define the affected spaces, symptom or acceptance question, timing, vessel activity and party who will use the report.
2. Freeze the operating-condition matrix
| Record | Minimum evidence | Why it changes interpretation |
|---|---|---|
| Vessel state | Berth, anchorage, harbour trial, sea trial, propulsion/generator load, cargo or coating work. | External sources and heat loads change with operation. |
| HVAC state | AHU/fan, damper, recirculation, filters, cooling/heating, exhausts and control set-points. | A display value does not prove delivered airflow or outdoor-air quantity. |
| Space state | Occupancy, doors/hatches, cleaning, smoking policy, recent refurbishment and complaint time. | Short unoccupied readings can miss the actual exposure condition. |
| Outdoor reference | Wind, weather, intake location and suitable outdoor measurements. | Helps separate an internal source from intake or ambient influence. |
3. Select IAQ measurements from the hypothesis
ISO 16000-1 describes why purpose, timing, location, frequency and duration must be settled before an indoor-air sampling strategy. For shipboard work, add deck, ventilation zone, intake and exhaust relationships, vessel operation and access limitations.
| Complaint or purpose | Useful first evidence | Limitation to declare |
|---|---|---|
| Stuffy cabin or fatigue | CO₂ trend, occupancy, temperature, relative humidity, outdoor-air/ventilation state. | CO₂ is an indicator; it does not identify every contaminant. |
| Fume or odour during operation | Timeline, CO where relevant, VOC screening or targeted sampling, intake/pressure/source-path checks. | Sampling outside the event can produce a false reassurance. |
| Dust or exhaust ingress | PM2.5/PM10 or agreed fraction, indoor/outdoor comparison, filter/intake condition and activity log. | Particle mass or count alone does not establish source. |
| Dampness or suspected microbial growth | Temperature/RH, surface and moisture investigation, airflow; targeted sampling only when justified. | A microbial result without moisture and location context cannot establish cause. |
| Commissioning or handover | Agreed contaminants, ventilation quantities, thermal conditions, representative-space plan and exceptions. | Use the specified project basis; do not import an unrelated building limit automatically. |
4. Prove what the ventilation system delivers
A ship HVAC and ventilation performance survey should distinguish total supply, outdoor air, recirculation, exhaust, transfer and pressure. High face velocity at one grille is not automatically total flow, and high air changes can coexist with low fresh-air delivery.
- Map AHU, intake, filter, coil, fan, branch, damper, terminal, return, transfer and exhaust.
- Choose duct traverse, capture hood, terminal velocity-area or another suitable method for the geometry.
- Record fan speed, damper positions, filter state, doors, simultaneous systems and weather.
- Compare design/agreed values, sister spaces and upstream/downstream points.
- Separate diagnosis from full testing, adjusting and balancing unless TAB is expressly scoped.
5. Convert symptoms into a causal test plan
| Observed problem | Compare | Likely decision path |
|---|---|---|
| Air feels stuffy despite strong supply | Outdoor-air fraction, recirculation, occupancy/CO₂ response, exhaust and transfer. | Correct fresh-air or balance issue; do not assume more total flow is enough. |
| Odour moves from toilet, galley or machinery area | Supply/exhaust balance, differential pressure, door/transfer condition and safe tracer observation. | Restore pressure direction or isolate the transfer path. |
| Some cabins have weak flow | Terminal totals, branch/damper state, fan condition and pressure loss along the path. | Locate restriction, leakage, control or distribution imbalance. |
| Condensation or high humidity | Temperature/RH distribution, surface risk, coil/control state, outside air and load. | Treat moisture control separately from simple comfort adjustment. |
| Too hot, too cold or drafty | Air temperature, mean radiant context, humidity, air speed, occupancy/activity and clothing assumptions. | ISO 7730 PMV/PPD analysis may be relevant when the agreed scope requires it. |
6. Record instrument and calibration evidence
The report should identify instrument, model, serial number, measured quantity, range/resolution where relevant, calibration status, field checks, sampling interval, averaging period and uncertainty or method limitation. For laboratory samples, add media, flow, duration, chain of custody, preservation, transport and analytical method.
Do not describe a sensor as “calibrated” without traceable evidence that covers the quantity and range used. Zero checks, bump checks and field comparisons are useful controls but are not substitutes for the required calibration.
7. Build a review-ready report package
- Vessel, space schedule, complaint/acceptance purpose and governing basis.
- Deck plan with sampling and airflow locations.
- Vessel, machinery, HVAC, occupancy and weather conditions.
- Instrument/calibration and laboratory chain-of-custody evidence.
- Time-series and spatial results with outdoor/reference comparisons.
- Calculations, assumptions, criteria and explicit deviations.
- Source-path diagnosis, ranked corrective actions and verification plan.
8. Class, flag and statutory context
The Maritime Labour Convention addresses adequate ventilation and, where applicable, air conditioning in seafarer accommodation. The exact survey, acceptance basis and witness requirement still depend on vessel applicability, flag law, class notation, approved plans, contract and the attending surveyor.
For ABS-, BV-, CCS-, CRS-, DNV-, IRS-, KR-, LR-, ClassNK-, PRS-, RINA- or Türk Loydu-classed vessels—and Singapore, Panama, Liberia, Marshall Islands, Bahamas, Malta, Cyprus, Hong Kong or Isle of Man flags—confirm the current project requirement before attendance. This guide does not claim supplier approval or guaranteed report acceptance.
9. What to send for a focused scope
- Vessel type/IMO number and berth, anchorage, port, shipyard or sea-trial window.
- Deck plan, HVAC schematic, air-balance schedule and affected spaces.
- Complaint timeline, occupancy and operating-condition history.
- Required standard, class/flag/contract review route and deadline.
- Known sources, recent retrofit/repair and available calibration or commissioning records.
Attendance can be assessed in Singapore, Malaysia, India, Sri Lanka, Indonesia, Thailand, the Philippines, the Middle East, Asia-Pacific and worldwide, subject to access and availability.