Pipeline coating

Fig. 3-26 Location of defects in the pipeline coating with ac by the Pearson method arrangement 1 parallel to the pipeline arrangement 2 at right angles to the pipeline (see caption to Fig. 3-24).

The sum reflects the corrosion likelihood of objects without extended cells as in Fig. 4-3b. This value also characterizes the class of soil, depending on which type of pipeline coating is selected [16]. The sum B, shows the corrosion likelihood of objects with extended cells as in Fig. 4-3c. This indicates that, in the case of extended objects, the class of soil is by itself not sufficiently informative. 

Measures for Achieving a Low Leakage Load 10.2.2.1 Pipeline Coating... 

Resistance to earth of the pipeline at the groundbed location. This resistance to earth depends on the quality of the pipeline coating. The better the coating the higher the resistance. 

The differences between asphalt and coal tar in relation to their application as pipeline coatings require comment. 

Table 14.7 Comparison of buried pipeline coating materials...

Test method for effects of outdoor weathering on pipeline coatings Definitions of terms relating to corrosion and corrosion testing... 

Holiday Detector a high-voltage low-current output generator with a built-in spark gap used for detecting pinholes (holidays) in pipeline coatings. 

ASTM G62-87 Standard test methods for holiday detection in pipeline coatings (withdrawn 2007)... 

Plastics Chemicals Pipeline Coatings Polymers Monomers... 

Failure to follow good practice in any of the above areas can result in an unacceptable coating. The special factors associated with these pipeline coating systems are as follows ... 

Test method for elTect of outdoor weathering on pipeline coatings. 

ASTM G8-96, Standard test methods for cathodic disbondmnet of pipeline coatings, in Annual Book of ASTM Standards, vol. 06.02, ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA, 1996. 

Another problem is the repair and rehabilitation of the pipeline coatings. In case the pipeline is damaged due to some mechanical failure or due to corrosion attack, or many old pipelines result in coating damage, repair of the coating is of prime importance. Again, there are several coatings used... 

Let me narrate an example that resulted in the disbondment of almost 500 km of pipeline, coated with 3LPE, just because no care was taken in measuring the surface cleanliness. A few tens of parts per million of salt remain after the surface preparation resulted in the disbondment (Figure 8.2). 

W.R. Roder. Coal tar enamel the protective pipeline coating of the past, present and what s new. Proceedings of the PIC on Conference, May 20, 2000, Canada. 

J. J. W.B. Cox. Three layer HDPE exterior pipelines coatings job reference and case histories. Proceedings of the 14th International Conference on Pipeline Protection, OcL 29-31, 2001, Barcelona, Spain. 

Inhibitors for Control of Corrosion in Pipeline Coating Industry.427... 

---