DCN Diving was contracted by Dubal Aluminum for the refurbishment of three seawater intake pipelines, each over 400m long, 2 metres in diameter, thick with marine growth, steel condition unknown. Cleaning, grit blasting and airless painting under hyperbaric conditions.
DCN was the only tenderer that offered the option to create a dry space within the intake in order to have a better-quality refurbishment. The challenge to conduct this work in the dry was due to the fact that the owner didn’t had any data on the current thickness of the steel wall. DCN came with a solution to enclose both ends of the intake by on one end placing a inflatable pipeline plug and on the other end a section was cut out and a riser was installed with a hyperbaric trucking in order to reach the job location.
Once this was achieved Divers conducted wall thickness measurements and the intake was considered safe for dewatering. Below a drawing of the situation.
Once dewatering was completed the intake was brought to atmospheric conditions in order for the coating technicians to conduct their work. The picture below shows the situation before the rufurbishment.
DCN ensured there was a fresh flow of air through the system and the technicians where properly monitored by DCN Life Support Personnel to safely conduct their work. The result of the work was phenomenal, which could never have been achieved when conducting it in the water. The lifetime of the intakes were increased by many years to come.