Finishing Offshore and LNG Modules
Offshore topsides, LNG process modules, pipe racks and skid packages are finished at a scale where the building becomes the booth. A module may be several stories tall, carry structural steel, piping, cable tray and equipment, and need a marine-grade coating system before it ships. The finishing work cannot happen in a catalog booth. It happens in purpose-built blast and paint halls, in enclosed sections of a fabrication shop, or in temporary enclosures around the structure, and it has to fit around welding, outfitting and load-out schedules. Here is how module yards and fabricators approach that work and what the mechanical side looks like.
Discuss your installationCoating Components Before Assembly Versus After
The first decision is what gets coated before assembly and what gets coated as a finished module. Coating structural members, pipe spools and plate in a shop blast room and paint booth is faster, cleaner and easier to inspect than coating the same steel once it is inside a congested module. Most yards push as much shop coating upstream as possible, then handle field welds, damaged areas and final coats on the assembled structure. That split shapes the facility: you need conventional blast rooms and booths sized for members and spools, plus a large hall or enclosure strategy for the assembled module.
- Shop-coated components: beams, columns, plate, pipe spools, grating supports.
- Module stage work: weld joints, touch-up, stripe coats and topcoats.
- Plan how coated components are protected during lifting and erection.
Blast and Paint Halls Built Around the Structure
A blast and paint hall for modules is essentially a large building with controlled ventilation, dust collection, lighting and access equipment. Modules typically enter on self-propelled transporters, skid tracks or rail, so the hall needs very large doors and a floor rated for the load. Ventilation is handled by large exhaust fans and dust collectors paired with heated or conditioned make-up air units, arranged to sweep air across the structure rather than letting it pocket in corners. Blast media recovery in a hall is often a combination of floor recovery in the main bay and vacuum recovery from upper levels of the module. Lighting has to reach inside the module, so portable fixtures rated for the environment supplement fixed high-bay lighting.
- Separate blast and paint phases or zones so dust does not land on wet coating.
- Provide access equipment, scaffolding anchors or lifts that can reach upper decks.
- Locate dust collectors and exhaust stacks away from neighboring fabrication bays.
Staging, Sequencing and Coordination With Fabrication
Coatings on modules are scheduled alongside welding, hydrotesting, insulation, electrical and instrument installation, and every trade wants the module at the same time. The finishing team needs clear windows when hot work is complete in an area, when temporary attachments have been removed, and when coating can proceed without being damaged by later trades. Many yards stage modules in the hall for blasting and priming, move them back to the outfitting area, then return them for final coats. Good staging space next to the hall, dry storage for coated components, and a plan for climate control during cure all keep the sequence moving. Communication between fabrication supervisors and the coating lead prevents rework, which is the largest hidden cost in module finishing.
Air, Dust and Utility Planning at Module Scale
Large halls require large utility services. Compressed air for multiple blasters and painters, electrical service for exhaust fans, dust collectors, dehumidifiers and lighting, and fuel or electricity for heating make-up air all need to be planned with the building. In humid coastal yards, dehumidification is often as important as heating because coatings and freshly blasted steel react badly to moisture. Exhaust ductwork, collector pads and make-up air units usually sit outside the hall along one wall or on the roof, and they need service access that does not block transporter routes. Fire suppression, interlocks and hazardous location wiring for spray zones should be reviewed early with the fire code authority and your insurer, since the hall may contain both blasting and spraying.
When a Temporary Enclosure Makes Sense
Not every yard needs a permanent hall. Temporary enclosures built from scaffolding and containment sheeting, fed by portable dust collectors, dehumidifiers and heaters, are common for one-off projects or modules too large to move. They require the same thinking on airflow, dust control and power, just on a temporary footing. For repeat module work, a permanent hall with installed fans, collectors and make-up air usually provides more consistent conditions and less setup time on each job.
Frequently asked questions
Can a standard paint booth handle module components?
Many components such as beams, plate and pipe spools fit in large industrial booths and blast rooms. The assembled module usually needs a hall or an enclosure built around it.
Why does dehumidification matter for module coating?
Freshly blasted steel can rust quickly in humid air, and many coatings need controlled moisture to cure correctly. Coastal yards often run dehumidifiers along with heated make-up air.
How do modules get into a blast and paint hall?
Typically on self-propelled transporters, skid tracks or rail. The hall doors, floor loading and approach have to be designed for the largest module.
Should blasting and painting happen in the same hall?
They can, but they should be separated in time or by zone, with dust cleanup between steps, so blast dust does not contaminate fresh coatings.
What utilities does a paint hall need?
Compressed air, electrical service for fans, collectors and lighting, heat or dehumidification for make-up air, and exhaust and dust collection with room for service access.
Is a temporary enclosure a reasonable alternative?
For occasional large jobs it often is. For steady module work, a permanent hall usually gives more consistent conditions and less setup each time.