Aydoghmoosh Water Transmission Line
This direct burial external pipeline coating project was installed under both harsh rocky terrain and river crossing conditions in a remote Middle East location. The project consisted of a large 94” diameter pipe, weighing 21 tons per 12 lineal meter section. The client was concerned about both the soil stress effect and the potential for damage during transportation and installation, all of which are exacerbated with larger diameter pipes in harsh conditions. The client wanted an external coating with superior mechanical strength, impact resistance, abrasion resistance, and corrosion resistance, to compensate for river and rocky terrain conditions.
The client’s search for the correct coating system encompassed complete ASTM testing of several external coatings including; butyl rubber, bitumen enamels, high build liquid epoxies, fusion-bonded epoxies, and 3-layer polyethylene. Nukote HT was selected for its superior performance in all categories of testing. The Nukote HT system was the only coating tested that passed all of the testing regimens.
The installed system was Nukote HT at 1.25mm (50 mils) DFT over Nukote MetalPrime II at 0.10mm (4 mils) DFT, over an abrasive blast profile of 0.80mm (3.5mil). The Nukote HT coating system was applied at Jonoobs Middle East coating facility using Nukote MLE-12 automated pipe coating equipment technologies. The coated pipes were transported by truck to the right-of-way job site without any defects.
The girth weld joints were coated, in conjunction with the pipe installation contractor, prior to backfill. The same Nukote HT system was utilized for girth weld joints using portable plural component spray equipment and certified field application teams. The speed of the field girth well coatings was another aspect of interest to the client allowing for backfilling within 12 hours of application, expediting the installation process. The client also reduced overall construction costs through the elimination of sweet fill in the rocky terrain. Backfilling was achieved using the same soils excavated on site.