Steel service reservoir external protective coatings management strategies

摘要

Melbourne Water (MW) is responsible for the delivery of approximately 474GL of bulk water per year to the Melbourne metropolitan retail water companies. A significant component of this water is transferred via 38 steel service reservoirs that are located at 23 separate sites across the Melbourne metropolitan area. Melbourne Water's steel service reservoirs are generally painted to protective coating standards, although there have been occasions where the lesser, architectural or maintenance standard have been employed. Whilst the protective coating standard is significantly higher than what is generally provided for the commercial, architectural or domestic market, its effectiveness in minimising corrosion over prolonged periods can be substantial in terins of both cost and on going maintenance. When considering best rehabilitation options for steel structures, costs associated with surface preparation, environmental waste management, protecting the community from adverse affects and workplace occupational health and safety have not always been fully considered when addressing the rehabilitation of the steel structure protective coating systems. As such, it has not been uncommon for such works to be either under valued; or, under funded. In an effort to minimise life cycle costs and ensure value for money, Melbourne Water has undertaken a cost benefit analysis to evaluate the economic benefit of utilising protective coatings versus the lesser architectural and maintenance standards. This comparison is based on the Melbourne Water's past coating practices and reflects asset condition monitoring over the past ten years. The results from this evaluation clearly demonstrate that there is a significant economic benefit in terms of both cost and asset-operating life where the protective coating standard is utilised. Given these results, Melbourne Water has adopted the protective coating standard as an important component of its asset management philosophy.