Spool Pipe Lining Project at PT Gunanusa Utama Fabricators
Project Summary
In 2025, PT Amman Mineral appointed PT Gunanusa Utama Fabricators as the fabricator for its Slurry Pipes Expansion Plant, covering spool pipe fabrication, internal lining, and external coating.
Every day, thousands of tons of slurry flow through the piping network in the mine’s production area. Abrasive particles in the slurry wear down the pipe walls continuously until they eventually leak and force production to stop. The right protection gives the pipes resistance against this wear.
As the Indonesian distributor for Sherwin-Williams PipeClad 8000, PT Suprabakti Mandiri was entrusted by Gunanusa to supply the material and carry out the spool pipe lining application. All work took place at the Gunanusa Yard in Cilegon, Banten.
Project Execution
Coating Material
The material used PipeClad 8000 from Sherwin-Williams, 100% solids, two-component polyurethane designed to protect piping from corrosion, abrasion, and impact. Its fast-curing property is a real advantage on site. A single spray pass is enough to reach the required thickness, and the surface can be handled within minutes after application.
Surface Preparation
Coating quality is not determined at the gun. It is determined at the surface preparation stage. The work began with dry abrasive blasting. Before blasting started, all equipment and abrasive media were checked with the criteria set by PT Amman Mineral.
Air from the compressor had to be free of oil, diesel, and water contamination, verified with a blotter test under ASTM D4285. Pressure at the blast nozzle tip was checked with a needle pressure gauge and had to reach at least 90 psi. This check was carried out routinely at every shift change, as part of the equipment readiness checklist.
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- Surface Preparation
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- Abrasive Blasting
Abrasive media also spot checked every 15 tons or once a week, with a maximum conductivity limit of 150 micro-Siemens/cm under ASTM D4940. For spools under 18 inches in diameter, the team used spinner blasting to work around limited access and keep quality consistent. All inspections were carried out by coating inspectors, and all blasting work was done by blasters.
Before moving to the application stage, surface preparation results were verified on three critical points. Roughness of at least 75 microns, measured with Testex Tape under NACE RP0287. Cleanliness of at least SSPC-SP5/NACE #1, or White Blast. And a contaminant test using a Bresle patch, with soluble salt under 20 mg/m2 under ISO 5802-6/9 and dust rated no higher than level 2 under ISO 8502-3. PT Amman Mineral and Gunanusa representatives witnessed every check in person
PipeClad 8000 Application
PipeClad 8000 for spool pipe lining was applied using plural component spray equipment, a method different from conventional coating tools or single leg airless sprayers. With a standard two pack material, components A and B are mixed before application.
This approach does not work for PipeClad 8000, since its curing time can be under 60 seconds. In a plural component system, mixing happens automatically at the tip of the gun, right before the material is released.
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- Graco Reactor H-XP3 Plural Component Spray Machine
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- Prural Gun Spray Anatomy
Before application began, the material went through a pre-heat process using the plural machine’s cycling system, to bring both components to the same temperature and viscosity. Pre-heating also gave the material early curing energy, which made it possible to reach a high thickness in a single pass without sagging or runs.
Application was carried out using two methods, manual and spinner coater. The spinner coater was used for diameters between 10 and 24 inches. All plural spray work was carried out by painters, either by an independent body or by the coating manufacturer.
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- Plural Spray Application Process
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- Plural Spray Application Process
Final Inspection
Spool pipe lining application results were verified in three stages. First, a 100% visual inspection to confirm there were no runs, sagging, pinholes, or missed areas. Second, DFT measurement, with a minimum thickness of 500 microns under SSPC-PA2. Third, high voltage discontinuity testing, or spark testing, under NACE RP0188. PT Amman Mineral and Gunanusa representatives witnessed every final inspection.
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- Inspection and Testing (Discontinuity Test and DFT)
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- Inspection and Testing (Discontinuity Test and DFT)
Project Outcomes
PT Suprabakti Mandiri completed surface preparation and internal spool pipe lining on 1,063 pipes, covering a total area of 7,550.51 square meters, in 120 days with a team of 24. Every spool pipe is protected to the client’s specification and ready for slurry flow at PT Amman Mineral’s expansion plant.
About the Client
PT Gunanusa Utama Fabricators is an Indonesian offshore construction company founded in 1980 and operating since 1983. The company provides project management, engineering, procurement, fabrication, construction, installation, hook-up, commissioning, and start-up services for onshore and offshore oil and gas projects.
| Location | Cilegon, Banten |
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| Product/Service | Sherwin-Williams |