Rust never sleeps: recoating of aboveground pipe adjacent to each block. The A number of abutments were unknown content of other older tenders received revealed that constructed to provide better coatings. Blasted waste material bulk water pipes in contractors were not willing to definition between above and below- was collected on groundsheets and accept responsibility for pipeline ground pipe and to allow adjacent disposed of at certified land-fills. Timely renovation of surface coatings The project immediate threat of pipe failure, not ruptures arising from the jacking buried pipe to be fully covered. These requirements were particularly is essential to maximise the life of Over 25 kilometres of the LinkWater undertaking immediate remedial and temporary works. While this Where underground coatings had arduous at elevated sections or where above-ground pipes and avoid loss of pipelines were built above ground work could result in the need for was understandable from the deteriorated, they were replaced the pipe crossed natural waterways. service during repair or replacement. for various historical reasons, a major renovation in a few years contractor perspective, LinkWater with a standard Denso Primer and LinkWater found that, while constructed typically of mild steel or eventually total failure and the was not prepared to allow the Densopol 80 HT wrap system. A Ongoing project appropriate preparation and product with a mortar lining. Today the need for full replacement. Given the works to proceed on an ‘all care, no SolarTech Laminate PE 55 fibreglass Ongoing inspection, condition choice are important, there are other exterior surface coatings are a mix critical nature of the pipe in relation responsibility’ basis and required an protective layer was installed where assessment and remedial works factors at play. This recoating project of corrosion-resistant paints, surface to the Water Grid and the potential alternative approach. only minimal cover was available. have been included in LinkWater’s demonstrates the importance of coatings, patches and graffiti. consequences of failure, the ’do At the same time, LinkWater agreed Asset Management Plan and work appropriate allocation of risk between nothing’ option was not acceptable The agreed solution used a product to trial the STOPAQ underground will continue on our above ground the contractor and asset owner, This project involved recoating by LinkWater. range from STOPAQ including anti- wrapping system, which may offer a pipelines identified as being in poor the potential to use new products approximately one kilometre of corrosion fillers and tapes. These viable option for future works. condition. Given the size of the innovatively and the importance 1060mm and 1670mm diameter Recoating specification are claimed to be impermeable to mains, environmental and access of considering stakeholder and mains running between the Mount The recoating specification was typical moisture and air and were used Other contract considerations constraints, the cost of the work is environmental issues. Crosby water treatment plant, the for such work: abrasive Garnite to seal the edges between the Although LinkWater has approximately $1,000 to $1,500/linear largest water treatment facility blasting to Class Sa 2½, followed supporting blocks and the pipe. Given easements and/or legal access for metre of pipe. Introduction in South-East , and by International Paint’s Interzine 42 that the concrete blocks are not maintenance, this pipeline runs LinkWater was formed as part of the the Brisbane water distribution (zinc-rich epoxy) with a topcoat of equally impermeable and corrosion largely through private land. An Project Profile submitted by ’s drought system. The pipelines, acquired from Interplus 1180 (surface tolerant high may continue at the block/pipe extensive lead-up of communication Paul Utting of LinkWater response to own, manage and Brisbane City Council as part of the build epoxy containing micaeous iron interface, a number of the supports and consultation with land-owners operate bulk water transport assets SEQ water industry restructure, are oxide). The preferred coating option will be dismantled in future to check was undertaken to provide for the in (SEQ). now almost 70 years old. offered a 15 year guarantee. the performance of this solution. works, contractor access and to LinkWater is now responsible for address any issues raised. approximately 535km of bulk water Project justification Pipeline supports Adjacent buried and partially- pipelines extending from Tugun on the A survey undertaken by Savcor The pipeline is supported on pairs buried pipe Environmental requirements were Gold Coast to Landers Shute on the on behalf of LinkWater found that of removable concrete blocks at While the project was focussed significant and all blasting and Sunshine Coast. These trunk mains some surface coatings were in approximately six metre spacing on above ground pipe, the painting had to be undertaken in link ’s dams, treatment poor condition and widespread to allow access to the entire pipe opportunity was taken to repair an enclosed space complete with plants and desalination plant with the surface corrosion was evident in surface. This requires jacking adjacent buried or partially air filtration. This was due to the three distribution/retailers. these areas. Although there was no and temporarily supporting the buried pipeline. known presence of zinc and the

Photo of pipe before coating Photo of above ground pipe recoating Photo of pipe after coating Photo of pipe after STOPAQ coating

38 Corrosion & Materials www.corrosion.com.au Vol 36 No 3 June 2011 39