A pre-application image of the unprotected pipe and valves.
Protal 7300 (UK) can be applied roller, brush or pad.
Protal 7300 (UK) can be applied to dry, damp or wet surfaces.
Protal 7300 (UK) can be applied to dry, damp or wet surfaces.
Wide angle view of the completed Protal 7300 (UK) application to the gas pipe in Dalmeny.
Denso Profiling Mastic can be seen to have completely filled the gap between the flange faces, thus preventing air pockets or space for water ingress into the void which could cause corrosion.
Denso PVC Self-Adhesive Tape (Yellow) is circumferentially wrapped to fully seal the void between the flange faces.
The floating dock under construction at CSSC Beihai Shipyard.
Pipelines at risk of being submerged are protected with Denso Glass Outerwrap HD UV, in addition to Steelcoat 100/400 System.
Exterior pipework is subject to changing environmental conditions.
Exterior pipework is subject to changing environmental conditions.
Exterior pipework is subject to changing environmental conditions.
A flange displaying primer, petrolatum tape and outerwrap tapes.
Protected pipework in the interior of the dock.
Completed system application to flanges.
Completed system application to straight pipe lengths.
Protected pipework in the interior of the dock.
The Grand Bahama Shipyard Floating Dock.
The Grand Bahama Shipyard Floating Dock.
ViscoMastic fills voids prior to the application of Viscotaq EZ Wrap.
The Viscotaq Tank Chime System overlaps from the tank shell to the annular plate and on to the concrete foundation.
Application of Viscotaq EZ Wrap to the tank chime.
Viscotaq EZ Wrap is easily cut and applied around any awkward profiles (e.g. anchor bolts).
The system is completed with a polyurethane topcoat.
DENSO P1 SYSTEM™ BOLT CORROSION TESTING REPORT
BACKGROUND
In the water industry it is common to install pipeline fittings with either plain stainless-steel bolts or differing steel grade bolts protected by a factory coating. While the fitting itself is often protected from corrosion by more robust means, the bolts are often overlooked and left without sufficient corrosion protection. Any corrosion protection provided by factory coatings can be easily damaged in transit or during installation. The unprotected bolts provide an opportunity for destructive corrosion to occur, leading to bolt failure and in turn, potentially dangerous and costly incidents. To combat this issue, Denso recommends the Denso P1 System™, designed for the protection of ferrous pipes, joints and fittings within the water industry in accordance with ‘Civil Engineering Specification for the Water Industry – 8th Edition’. It comprises a coat of Denso Paste™ followed by the use of Denso™ Profiling Mastic to fill any voids over joints to form a smooth profile. The system is completed by the application of a double layer of Denso Tape™.
1. Denso Paste™ is used to create the initial layer of corrosion prevention in the complex surfaces.
2. Application of Denso™ Profiling Mastic to fill any voids and create a smooth profile for wrapping the fitting.
3. A complete Denso P1 System™ after the application of Denso Tape™, applied with a 55% overlap.
TESTING
In this investigation, bolts were installed onto a small-scale version of a common water pipeline fitting and Salt Spray testing was performed to replicate a highly corrosive environment. Three different bolt types were tested to represent the commonly used bolt materials and factory coatings. Half of the samples were protected with the Denso P1 system™, and the other half were left unprotected, as received from the supplier.
Note: Salt spray exposure was performed based on ASTM G85-19 (Annex A5, X6) for 2000h.
Denso™ Profiling Mastic applied to the test fitting after the torquing of bolts and application of Denso Paste™.
Double layer of Denso Tape™, applied spirally, to complete the system ready for salt spray testing.
RESULTS & CONCLUSIONS
The results demonstrate the severity of corrosion that can occur on bolts which are not protected by the Denso P1 System™. All bolt types showed significant corrosion when unprotected however all the samples protected with the Denso P1 System™ did not display any signs of corrosion.
BOLT TYPE 1 UNPROTECTED |
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BOLT TYPE 1 PROTECTED |
BOLT TYPE 2 UNPROTECTED |
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BOLT TYPE 2 PROTECTED |
BOLT TYPE 3 UNPROTECTED |
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BOLT TYPE 3 PROTECTED |
 BOLT TYPE 1 UNPROTECTED |
BOLT TYPE 1 PROTECTED |
BOLT TYPE 2 UNPROTECTED |
BOLT TYPE 2 PROTECTED |
BOLT TYPE 3 UNPROTECTED |
BOLT TYPE 3 PROTECTED |
The new 700mm diameter pipeline in Strathclyde Park.
The petrolatum tape system was applied to the pipe (right) before it was lifted onto the steel support brackets (left).
The new 700mm diameter pipeline in Strathclyde Park.
The HDPE jackets are installed with tensioning equipment and secured with stainless steel bolts.
A completed SeaShield 2000FD jacket installation.
