Marine safety service
Calibration Services
Calibration of marine instruments including gas detectors, pressure gauges, thermometers, pressure switches, torque tools and 15 ppm bilge alarms, with traceable certificates.
Overview
Marine instrument calibration services
Marine instrument calibration services check that the gauges, sensors and test equipment used on board give correct readings, and adjust or replace them when they do not. Readings from gas detectors, pressure gauges, thermometers and oil content meters are used to make safety and pollution decisions: whether a tank is safe to enter, whether a fire main has pressure, or whether oily water can be discharged. An instrument that reads wrong can be more dangerous than no instrument at all.
vslSafety coordinates calibration laboratories and field technicians at the vessel's port to calibrate instruments on board or collect them for workshop calibration, and to return them with traceable certificates before the ship sails where possible.
Regulatory requirements and standards
SOLAS regulation XI-1/7, in force since 1 July 2016, requires ships to carry appropriate portable atmosphere testing instruments for enclosed space entry, capable of measuring at least oxygen, flammable gases or vapours, carbon monoxide and hydrogen sulphide, with suitable means to calibrate them. Guidance on selection is in MSC.1/Circ.1477, which expects instruments to be calibrated according to the manufacturer's instructions. Tankers have additional requirements for gas detection under SOLAS chapter II-2.
For pollution prevention equipment, resolution MEPC.107(49), as amended, requires the accuracy of 15 ppm bilge alarms to be checked by calibration and testing carried out by the manufacturer or persons authorised by the manufacturer, and the calibration certificate to be kept on board. Its validity is checked at IOPP annual, intermediate and renewal surveys. The ISM Code requires the company to maintain the ship and its equipment, and most safety management systems include a calibration schedule for measuring instruments. Class rules and makers set further calibration requirements for machinery instruments.
Inspection and servicing intervals
| Item | Requirement | Interval | Reference |
|---|---|---|---|
| Portable multi-gas detectors | Calibration and bump testing with certified gas | Per maker's instructions; bump tests often before each use | SOLAS XI-1/7, MSC.1/Circ.1477 |
| 15 ppm bilge alarm | Accuracy check by maker or authorised person; certificate on board | Validity checked at IOPP surveys; maker sets calibration period | MEPC.107(49) as amended |
| Fixed gas detection systems | Sensor calibration and alarm tests | Per maker and class requirements | SOLAS II-2, class rules |
| Pressure gauges and thermometers | Comparison against reference standards | Per company planned maintenance system | ISM Code, class rules |
| Torque wrenches and test instruments | Calibration to recognised standards | Per company procedures and maker guidance | ISM Code |
What the service includes
- Calibration of portable single and multi-gas detectors, including sensor replacement and bump test verification
- Calibration of fixed gas detection sensors for cargo areas, pump rooms and machinery spaces
- Calibration of oxygen analysers for inert gas systems and portable oxygen meters
- Pressure gauge and pressure switch calibration using dead-weight testers or calibrated references
- Thermometer, temperature sensor and transmitter calibration
- 15 ppm bilge alarm and oil content meter calibration by maker-authorised technicians
- Torque wrench, multimeter, insulation tester and other workshop tool calibration
- Supply of calibration gas cylinders and spare sensors
- Calibration certificates with traceability to national standards and next due dates
Equipment types covered
Instruments commonly handled include portable gas detectors from makers such as Dräger, MSA, Riken Keiki, BW Technologies and Industrial Scientific; fixed gas detection systems; oil content meters and bilge alarms from makers such as Rivertrace, Deckma and Brannstrom; and general instrumentation such as pressure gauges, thermometers and torque tools. Oil content meter work is also covered in more detail under oil content meter and bilge alarm calibration, and gas detection systems under gas detection equipment.
Common defects and PSC deficiencies
- Portable gas detector calibration out of date, or no record of bump testing
- Calibration gas expired or not matched to the instrument
- 15 ppm bilge alarm without a valid calibration certificate
- Fixed gas detection sensors faulty or not calibrated, causing false or missing alarms
- Pressure gauges on fire mains or other safety systems broken or reading incorrectly
- No calibration schedule in the planned maintenance system
Certificates and documents you receive
Each instrument receives a calibration certificate listing the serial number, reference standards used, readings before and after adjustment, and the next due date. Where a laboratory is accredited, the certificate states the accreditation. For 15 ppm bilge alarms, the certificate is issued by the manufacturer or its authorised agent. A summary list is provided for the ship's records.
How to prepare the vessel
Collect the instruments to be calibrated, with serial numbers, previous certificates and manuals. Decide which items can leave the ship and which must be calibrated in place. Make sure the ship still has working gas detectors for enclosed space entry while others are ashore, or ask about loan units. For fixed systems, plan the attendance so alarms can be tested without disrupting operations.
Information needed for a quotation
- Vessel name, IMO number, flag and class
- Port, ETA and ETD
- List of instruments with maker, model, serial number and quantity
- Last calibration dates and copies of previous certificates
- Whether calibration must be done on board or can be done ashore
- Requirements for calibration gas, sensors or loan instruments
vslSafety coordinates a suitable calibration provider at the vessel's port and confirms scope, timing and cost before attendance.
Frequently asked questions
How often should portable gas detectors be calibrated?
SOLAS regulation XI-1/7 and MSC.1/Circ.1477 require instruments to be calibrated according to the manufacturer's instructions. Many makers call for full calibration every six or twelve months, with a bump test before each use. Company procedures and charterer or vetting requirements can be stricter, so check your safety management system.
Who can calibrate a 15 ppm bilge alarm?
Resolution MEPC.107(49), as amended, requires the accuracy of 15 ppm bilge alarms to be checked by the manufacturer or persons authorised by the manufacturer. A calibration certificate must be kept on board and its validity is checked at IOPP surveys. Alternatively, the measuring cell can be replaced with a calibrated unit.
What is the difference between a bump test and a calibration?
A bump test briefly exposes the gas detector to a known gas to confirm that sensors respond and alarms work. A calibration adjusts the instrument's readings to match a certified reference gas at set concentrations. Bump tests are done frequently by the crew; calibration is done at longer intervals by trained staff with certified gas.
Can instruments be calibrated on board?
Many instruments, including gas detectors, pressure gauges and bilge alarms, can be calibrated on board by a field technician. Some items, such as reference thermometers or torque wrenches, may need to go to a laboratory ashore. Plan enough time in port or arrange delivery to the next port.
