Exhaust gas cleaning system piping checks for scrubber ships calling at Maasvlakte and Europoort

Why are scrubber ships at Rotterdam so exposed to piping wear?

The North Sea emission control area makes a scrubber the economic choice for large ships that spend most of their time on routes into and out of Rotterdam. Container ships on Asia and transatlantic services, tankers working Europoort and ships running regular North West Europe loops all carry them. When the port restricts open-loop discharge, the ship switches to closed-loop or fuel changeover and the pipework sees different conditions: stagnant wash-water in a closed system or intermittent flow in an open one.

Both are hard on metal. Acid wash-water with chlorides attacks carbon steel, and stagnant sections allow deposits and crevice corrosion to form under them. The wear is rarely uniform: it concentrates at bends, valves, pump discharges and the point where the pipe meets the shell, and it often hides under insulation or lagging in the machinery spaces.

The rules on wash-water discharge in North Sea ports change over time, so before running the system alongside, the ship's agent should confirm the current position. Our inspection depends on the system being stopped and drained, which is the usual state at berth.

How is scrubber piping scoped for a ship on a short call?

We scope from the system's piping diagram and the maker's description. The chief engineer marks the runs by material and by service: inlet from the sea chest, wash-water supply, discharge from the scrubber tower, the treatment plant connections and the overboard line. Then we agree which sections can be reached and which need lagging removed or staging built, and plan the work to fit the call.

On a typical ship the sequence begins with the overboard section and its shell connection, because that is the failure that matters most. Then we gauge bends, tees and valve bodies in the discharge run, followed by the flanged joints. Weld seams on carbon steel and duplex lines are examined by magnetic particle or penetrant testing as the material allows. Fibreglass runs are inspected visually and by tapping, and we look at the joints and the supports.

The result is a record of wall thickness against the original at each station, with the corrosion pattern marked and any weld indications described. If a reading is near the limit the owner and the maker can use the data to decide whether to replace the section at the next opportunity, and the interval for the next check follows from the measured loss rate.

How should a scrubber piping check at Rotterdam be planned?

Send us the system maker and type, the pipe materials, the diagram if you have it and the ship's schedule at Rotterdam. Tell us whether the system is open-loop, closed-loop or hybrid, and which sections the engineers already suspect. We then agree who isolates and drains the lines, who removes lagging and what permits the terminal requires.

Container ships have the shortest windows, so we plan these jobs with parallel teams on different sections. The agent submits names for terminal access in good time, and because the team travels from India each member needs a Schengen visa, so we ask for the schedule as early as the owner knows it.

If the check shows a section near its limit, we report it to the chief engineer on site before the ship sails, and the written report gives readings and positions the maker or the yard can use to plan replacement.

Who does the work

The inspection team is mobilised from India for each job; nobody is stationed at the port, so mobilisation is planned against the vessel's schedule and visa lead times. Our founder and Responsible NDT Level III, who holds ASNT NDT Level III in UT, RT, MT, PT and VT and has over eleven years of international field experience, plans and supervises the work. Technicians are certified under the company's written practice to ASNT SNT-TC-1A, and the company holds ISO 9001 and ISO 14001 certification.

Frequently asked questions