How do you maintain a portable gas detector on board?

To maintain a portable gas detector on board, you need to carry out regular bump tests before each use, perform a full calibration at least every six months (or according to the manufacturer’s schedule), store the device correctly between uses, and keep accurate maintenance records. These steps keep the detector reliable and help you stay compliant with maritime safety requirements. Below, we answer the most common maintenance questions in plain terms.

How often should a portable gas detector be calibrated?

A portable gas detector should be calibrated at least once every six months, though many manufacturers and classification societies recommend calibrating every three months in demanding maritime environments. The exact interval depends on how frequently the device is used, the types of gases it measures, and the conditions it is exposed to on board.

Calibration involves exposing the detector to a known concentration of test gas and adjusting the device so its readings match that reference. Over time, sensors drift, meaning their output gradually becomes less accurate even without any visible damage. On a ship, factors such as salt air, humidity, temperature swings, and exposure to high concentrations of gas during enclosed space entry can accelerate this drift.

In practice, the safest approach is to follow the manufacturer’s recommended interval and cross-reference it with the requirements of your flag state and classification society. If the detector is used intensively, for example during cargo operations or frequent enclosed space entries, calibrating every three months is a sensible standard. Always document each calibration with the date, the test gas used, and the result.

What is the difference between a bump test and calibration?

A bump test is a quick functional check that confirms a detector’s sensors respond to gas, while calibration is a precise adjustment that verifies and corrects the detector’s accuracy against a known reference gas concentration. Both are important, but they serve different purposes and should not replace each other.

During a bump test, you briefly expose the detector to a small amount of test gas. If the alarm triggers, you know the sensors and alarms are working. A bump test does not tell you whether the reading is accurate, only that the device responds. This is why bump tests are done before every single use, particularly before entering an enclosed space.

Calibration goes further. It measures the detector’s output against a certified reference gas and adjusts the instrument so the reading is accurate within an acceptable tolerance. This is a more involved process that requires proper equipment and certified test gases. Some vessels carry calibration kits on board; others send detectors ashore for this work.

Think of it this way: a bump test is your daily safety check, and calibration is your periodic accuracy check. Skipping bump tests puts crew at immediate risk. Skipping calibration means you cannot trust the numbers the detector shows.

How do you store a portable gas detector safely on a ship?

Store a portable gas detector in a clean, dry location away from direct sunlight, extreme temperatures, and corrosive atmospheres. The storage area should have good ventilation, and the device should be kept away from solvents, paints, or chemicals that could contaminate or damage the sensors.

On a ship, the storage environment matters more than many people realise. Salt air and condensation can degrade sensor membranes over time, and storing a detector near engine rooms or paint lockers can expose sensors to background concentrations of gas that cause premature wear or false readings.

A few practical storage guidelines:

Keep the detector charged or with fresh batteries so it is ready for immediate use.
Store in its protective case to prevent physical damage to sensors and display.
Avoid storing near strong magnetic fields or heavy electrical equipment.
Do not store in airtight containers with residual gas or chemical vapours.
Check the sensor caps and filters regularly for dust or moisture build-up.

If the vessel operates in cold climates, allow the detector to warm up to operating temperature before use. Most portable gas detectors have a specified operating temperature range, and readings taken outside that range may not be reliable.

What are the signs that a gas detector sensor needs replacing?

The main signs that a sensor needs replacing include slow response times, readings that drift or fail to return to zero in clean air, failure to pass calibration within tolerance, and alarm activation at concentrations that do not match the test gas. Physical damage to sensor ports or filters is also a clear indicator.

Sensors have a finite lifespan. Electrochemical sensors used for gases like carbon monoxide and hydrogen sulphide typically last two to three years under normal conditions. Catalytic bead sensors for flammable gas detection can be poisoned by silicones or lead compounds and may fail earlier. Non-dispersive infrared (NDIR) sensors used for carbon dioxide detection generally last longer but still require periodic validation.

Watch for these specific warning signs:

The detector fails a bump test, meaning it does not alarm when exposed to test gas.
During calibration, the sensor cannot be adjusted to read within the acceptable tolerance range.
The detector gives erratic readings in clean air or takes unusually long to stabilise.
The device displays a sensor fault or low sensor signal warning on screen.
The sensor has exceeded the manufacturer’s stated service life, regardless of apparent performance.

Do not wait until a sensor fails completely. In an enclosed space entry situation, a sensor that gives a false “safe” reading is more dangerous than one that is visibly broken. If you have any doubt about a sensor’s reliability, replace it before the next use. Our fire and gas detection team can advise on compatible replacement sensors for a wide range of detector models.

Which maintenance records are required for portable gas detectors on board?

Ships are required to maintain records of calibration dates and results, bump test logs, sensor replacement history, and any repairs carried out on portable gas detectors. These records support compliance with SOLAS requirements and are reviewed during Port State Control inspections and internal audits.

Under IMO Resolution MSC.581(110), which entered into force in December 2025, the requirements around atmospheric testing documentation have become more stringent. Test results must be recorded before entry into enclosed spaces, and an unrecorded test is treated by inspectors as a test that did not take place. This makes accurate record-keeping a direct safety and compliance issue, not just an administrative formality.

At a minimum, your maintenance log for each portable gas detector should include:

The device serial number and model.
Date and result of every calibration, including the test gases and concentrations used.
Date and result of each bump test (or a note that one was performed before use).
Dates of sensor replacements and the sensor type installed.
Any repairs, firmware updates, or servicing carried out.
The name of the person who performed each check.

Many shipping companies now maintain these records digitally and synchronise them with the shore-side office, which aligns with the requirements for the Enclosed Space Register introduced by MSC.581(110). Paper logs are still acceptable but must be legible, complete, and available for inspection at any time.

Can portable gas detectors be serviced on board or do they need to go ashore?

Basic maintenance such as bump testing, sensor filter cleaning, battery replacement, and visual inspections can be carried out on board by trained crew. Full calibration can also be done on board if the vessel carries the correct calibration equipment and certified test gases. More complex repairs, sensor replacements, and full overhauls typically require specialist workshop facilities ashore.

Whether on-board servicing is sufficient depends on the type of work needed and the equipment available. Many modern portable gas detectors are designed with on-board maintenance in mind, with user-replaceable sensors and straightforward calibration procedures. However, the calibration gas cylinders required must be within their certified expiry date, and the person performing the calibration must be competent to do so.

For repairs involving internal components, firmware issues, or sensor types that require specialist handling, sending the unit to a certified service centre is the right approach. Our service and repair facility in Rotterdam handles calibration, overhaul, and sensor replacement for a wide range of portable gas detection equipment, with fast turnaround times to minimise disruption when a vessel is in port.

A practical approach for most vessels is to carry out on-board bump tests and calibrations as part of routine maintenance, and schedule a full workshop service for each device at least once a year or whenever performance issues arise.

How Lavastica helps with portable gas detector maintenance

We understand that keeping gas detection equipment in good working order is not just a compliance requirement, it is a matter of crew safety. At Lavastica, we support fleet engineers and technical superintendents with everything they need to keep portable gas detectors reliable and compliant:

Replacement sensors and spare parts for a wide range of detector models, including older and discontinued equipment.
Calibration and overhaul services at our Rotterdam workshop, with fast turnaround for vessels in port.
Supply of certified calibration gases for on-board maintenance programmes.
Technical advice on sensor compatibility, replacement options, and compliance with current IMO requirements including MSC.581(110).
Emergency delivery of replacement detectors or sensors when a vessel cannot wait for a repair.

Whether you need a single replacement sensor or a full maintenance plan for your fleet, we are ready to help. Learn more about us or get in touch directly to discuss your situation. You can reach us by phone at +31 (0) 10 265 5070 or by email at info@lavastica.com.