Piping Fabrication and Installation
The piping fabrication isometrics are taken from the design drawing and fabricated to these. The estimate is taken from the drawings in order to ascertain the lengths of pipe, number gaskets and bolts along with the number of fittings and welds. Materials for ships piping are normally cuni-copper/nickel, stainless, and carbon steel, so different NDT is required, including radiography if pipes are high pressure oil or gas.
Magnetic Particle Inspection (MPI) for carbon steel fillet welds is the cheapest method, and usually only a percentage of welds are examined, unless there is a problem found.
Costing is based on the total length and type of materials, number of welds, and number of fittings. Also estimated is the pipe supports fabrication, shot blast, painting and installation, along with the associated hydro-testing required on the completed runs.
HVAC Fabrication, Installation and Testing
Fabrication drawings are made from the clients design drawings, and from these the material required to fabricate the HVAC ducting spools is estimated.
Components such as fans, dampers, and filters are shown on the drawings and costed.
Some HVAC ducting is fabricated from stainless steel, particularly for use in the accommodation and galley, but the majority is from carbon steel sheet.
Once fabricated the carbon steel spools are hot-dipped galvanized before being installed along with the different components and pressure tested for leaks.