LNG Tanks

In 2011 Austin Hayes Ltd were delighted to be chosen as the preferred contractor to process five vaporiser tanks for Process Combustion Ltd. The end customer was one of Europe’s largest high pressure gas pipeline transporter manufacturers.

The vaporiser tanks required coating with two different paint systems; in accordance with paint specifications AD W-PE 1440 System 1 (internally) & AD W-PE 1440 System 3 (externally).

Internally: Abrasive grit blasting to SA2.5 (IS0 8501-1:2007) or SSPC SP10 60-80 microns amplitude medium surface roughness. The substrate then has three coats of protective coating applied, Sigma Phenguard 930 (off white) as the primer, Sigma Phenguard 935 (Pink) as the intermediate and Sigma Phenguard 940 (Grey) as the finish coat, with a final thickness of 300 microns. Sigma Phenguard has excellent resistance to a wide range of organic acids, alcohols, edible oils, fats and oils and has a good resistance to hot water.

Externally: Abrasive grit blasting to SA2.5 (IS0 8501-1:2007) or SSPC SP10 60-80 microns amplitude medium surface roughness. The substrate then has a 3 coat system applied externally, primer coat of Sigmazinc 102HS, Intermediate coat of Sigmacover 630 and a finish coat of Sigmadur 540 Black to BS4800 00.E.53, with a final dry film thickness of 240 microns.

The project, comprising five tanks, lasted from April to July; each tank taking approximately 14 working days to complete.

After the blast stage, each tank had to be masked before the first coating could be applied. The masking operation took four hours per tank and was of vital importance to the success of the completed job. The anodes inside the tank (see photo), flange faces and threaded holes all needed protecting. Different internal and external paint systems required careful and accurate masking where the two systems met.

Our coating team had to stripe coat and apply both primer coats in the same day within 8 hours of the tanks being blasted, before the blasted steel surface deteriorated. The stripe coat, which involves manual brushing of edges, welds around the anodes and awkward areas, is a lengthy process on a job of this size and occasionally required the help of the management team to ensure the timetable was adhered to.

Steve Swaine our NACE qualified inspector carried out the inspections as part of the project requirements. These included the wet sponge test using his Elcometer 270, which detects pin holing, Testex Inspection for surface profile, dry film thickness using a calibrated DFT gauge, adhesion testing using hydraulic equipment. He also took readings for temperature and humidity regularly.

The whole project was also inspected by a third party inspector from the Netherlands employed by the end customer and Process Combustion’s inspector.

The end customer has had previous experience of Austin Hayes’ work and had specified to Process Combustion when placing the order that they would like them to use us as the painting contractor. Process Combustion has been a long-standing customer of Austin Hayes and we are proud to be associated with such a reputable company.