Corrosion Under Insulation (CUI) in pipingc systems consumes a significant percent of the maintenance budget in the petrochemical industry. Prevention of CUI by the use of (1) thermal spray aluminum, (2) stainless steel pipe, (3) expanded metal cages for personnel protection instead of insulation and (4) aluminum foil wrapping are discussed in terms of long term protection, installed cost and Life cycle cost.
This document captures the key components required to get Thermal spray aluminum (TSA) coating installed by material engineering, project design and execution. These execution details apply to any TSA and insulation system installation whether it is a new construction project or in-plant maintenance project.
Operators desire extended life of offshore facilities, structures and components to improve affordability, and to increase their availability in later years of operation. Whilst maintenance and replacement of topside facilities is possible, critical to this objective is the design and construction of supporting infrastructure and facilities capable of withstanding splash and tidal zone corrosion for the lifetime of the structure with minimum maintenance.
Thermally sprayed aluminum (TSA) is increasingly applied in marine environments as a corrosion mitigation solution but few studies provide quantitative corrosion rate data, from which a lifetime of little or no maintenance can be predicted. A technology review was undertaken to establish current working practice and experience related to the mitigation of splash and tidal zone corrosion. A number of coating systems (thermally sprayed, organic paints and duplex combined thermal spray and paint), currently used in the splash and tidal zone of offshore structures, were identified. Thermal spray coatings with and without aluminum-silicone sealant were prepared and tested in alternate immersion using linear polarisation resistance (LPR) methods. The data were analysed and corrosion rates values were obtained.