Ship Thickness Gauging in Porsgrunn and the Grenland Industrial Ports

Inspection services for ships at Porsgrunn

Each service has its own page with the method, the class requirements and what the report contains.

Industrial berths, terminals and lay-by options in Grenland

Most gauging in Grenland happens alongside at the plant berths, under the plant's own safety regime as well as the ship's. At gas and ammonia berths, electronic equipment may be restricted in hazardous zones on deck, and the team agrees with the terminal and the master which spaces can be entered and which instruments are allowed where. Ballast tanks, the engine room, the steering gear flat and piping around the accommodation are usually accessible; cargo tanks, compressor rooms and areas inside the hazardous zones are left for gas-free conditions. Cement and bulk berths are simpler, with holds reached once discharge or loading has stopped and the space has been ventilated.

Grenland is not a major docking centre for these ships. Gas carriers, CO2 carriers and chemical tankers dock at specialised yards in northern Europe or further afield, and cement carriers and coasters at yards on the Norwegian and Danish coasts. A ship with a longer stay, perhaps waiting for a berth or for cargo, can lie at a lay-by quay or at anchor in the outer fjord, which opens the chance to gauge spaces that need more preparation. Pre-docking readings taken in Grenland give the yard and the class surveyor an early view of the steel work to come.

• Rafnes gas berths — ballast tank, deck and engine-room piping gauging on ethane and LPG carriers, within the terminal's hazardous-zone rules.
• Herøya industrial quays — hold, tank-top and coaming readings on fertiliser bulk ships, and ballast work on gas carriers serving the plant.
• Brevik cement and CO2 berths — hull, ballast tank and machinery piping measurements on cement carriers and liquefied CO2 carriers.
• Grenland Terminal at Brevik — scrubber pipework, deck and void-space gauging on container and general cargo ships during cargo work.
• Outer-fjord anchorage and lay-by quays — longer scopes on ships waiting for a berth, arranged through the agent.
• Owner-selected docking yards — renewal survey gauging and crack detection on cargo containment, following pre-docking work in Grenland.

Gas-carrier, CO2 and chemical regulation behind Grenland gauging

Port state control in Grenland is carried out by the Norwegian Maritime Authority under the Paris MoU, and because tankers and gas carriers are among the ship types weighted in Paris MoU targeting, the ships calling here see inspectors regularly. Chemical and oil tankers are ESP ships, so their renewal surveys bring extended gauging and close-up survey of cargo and ballast tanks as they age. Gas carriers sit outside the ESP Code but follow class rules for liquefied gas carriers, where hull gauging concentrates on ballast tanks, the double bottom, hold spaces and deck, and the cargo tanks are examined under the gas-carrier survey requirements. Ammonia carriers bring an added concern: carbon-manganese steel in ammonia service can suffer stress corrosion cracking, so owners look for cracks at cargo tank welds when the tanks are opened, usually at a docking.

Liquefied CO2 shipping is new, and the ships serving Brevik are among the first purpose-built carriers for carbon capture and storage, with pressurised cargo tanks holding CO2 at low temperature. Their hulls and ballast systems are conventional steel structures, and owners will want baseline readings early so that corrosion can be tracked from the start rather than discovered at a later renewal survey. Norway was the first country to ratify the Hong Kong Convention on ship recycling, which entered into force in June 2025. For older tankers and bulk ships calling in Grenland, the Inventory of Hazardous Materials required for ships trading to EU ports and the gauging programme often share the same docking.

Ships trading to Porsgrunn are inside a sulphur emission control area, where fuel must not exceed 0.10% sulphur unless an exhaust gas cleaning system (scrubber) is fitted. Scrubber wash-water piping, the overboard discharge and the hull penetration around it are among the fastest-corroding parts of a modern ship, so they belong in the gauging scope at every docking and, on open-loop systems, between dockings.

How a thickness measurement job runs at Porsgrunn

The sequence for a thickness measurement job at Porsgrunn is short and written down, so the yard, the surveyor and the superintendent know who arranges what.

Sandefjord Airport Torp is the closest airport with international flights, and Oslo Airport at Gardermoen is the main alternative, with rail and road links to Porsgrunn and Skien. The plant berths at Rafnes, Herøya and Brevik each require their own induction and work permits in addition to ISPS access, so the ship's agent and the plant need the team's details well before the call. Norway is a Schengen country; the technicians travelling from India apply for Schengen visas, and frequent callers on fixed rotations make the planning straightforward.

• Send the vessel name or IMO number, ship type, class society, the survey due (annual, intermediate, renewal survey number, CAP or owner's condition survey), the port and dates, and the scope you expect.
• We confirm the scope against the class rules for that survey, prepare the thickness measurement plan with frame and section references, and say whether the measurement will be credited to a class survey.
• Mobilisation is planned around visa lead times and the vessel's schedule; the ship's agent arranges port access, and the yard or ship arranges staging, lighting, ventilation and gas-free certificates.
• Gauging with calibrated ultrasonic thickness gauges: through sound coatings only where the gauge's through-coating mode has been verified on a coated reference, otherwise on cleaned bare steel, with every reading tied to its frame, strake and location on the sketch.
• Readings are compared with original thicknesses as work proceeds; substantial and excessive corrosion and any cracks are reported to the attending surveyor and the superintendent the same day.
• The final report is issued on the class thickness-measurement formats with sketches, a summary of locations exceeding the allowable margins, piping tables where piping was in scope, and the gauge calibration and technician certificates.

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