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Parmelia Pipeline Dn350 Gas Line

Buried Coatings

Project Data

LocationPerth Basin Gas Fields (WA)
ProductsDenso Paste & Protal 7300 & S43/R23 self-amalgamating butyl
tape system
DateJuly 2017
Ref NoB036

Project Details

Denso Australia was approached by APA, Perth, Western Australia to provide a suitable quick turn-around solution to re-coat a damaged section of pipe, DN350 (14 inches) gas-line that suffered some minor mechanical damage. The Protal 7300 and Denso Butyl Tape System were applied to repair a damaged section of the Parmelia gas pipeline exposed to permanent wet conditions located near a water canal. APA owns and operates the 416km Parmelia pipeline, which transports gas from Perth Basin gas fields near Dongara (south of Geraldton), the Carnarvon Basin (via the Dampier to Bunbury Natural Gas Pipeline) and APA’s Mondarra gas storage facility, to customers in the Perth area and the south west of Western Australia.

APA’s elected repair method was a ‘stand-off’ sleeve, which was welded into place and the annulus filled with a liquid epoxy. Once completed, the exposed section of the pipeline was abrasively blasted to Sa2.5 with a 50-70 micron surface profile and coated with Denso Protal 7300 to a DFT of 750 microns. For added protection and ‘peace of mind’ the decision was made to also overwrap the cured Protal 7300 with Denso S43/R23 self-amalgamating butyl tape system. The S43/R23 self-amalgamating butyl tape system was applied spirally under tension with a 55% overlap, giving an added 2500 microns of corrosion and mechanical protection. Profiling of the step-down areas had first been completed with using butyl mastic strip to ensure there was no bridging of the subsequent tape wrap, which would have left void
areas under the completed system. This was then followed with the brush application of Butyl Primer, which was used to promote adhesion to the underlying coating. Protal 7300 was the preferred liquid coating as it is specially formulated to coat dry, damp or wet surfaces. It is VOC free; a 100 per cent epoxy high-build liquid coating that can be applied by an applicator pad, brush or roller in one coat.

All the works were performed by Petroleum and Mining Engineering in the allocated time frame to the satisfaction of the client.