This paper will address common issues facing inspectors that are specific to the pipeline coating community. Much of the coating inspection reviewed in NACE Coating Inspector Program (CIP) courses are geared much more toward liquid coatings for structural applications. This leaves many pipeline issues that aren't addressed resulting in CIP inspectors who are untrained regarding the pipeline coating types and what to watch for.
The bulk of a pipeline coating is shop applied and those processes are typically automated. Because the automation of pipeline coating has so many controls, there is little need to address the inspection on the body of the mainline coatings. As such, this paper will address inspection of pipeline specific coating types and their unique considerations in a field environment. It will address concerns around tie-ing into other coating types and compatibility. Field joint coatings that will be addressed include Fusion Bonded Epoxy (FBE), 2 Part Epoxy, Flame Sprayed material, Injection Molding, Heat Shrink Sleeves and tape wrapping, all issues not typically addressed in CIP.
This paper will give an overall guide for pipeline inspectors to have some basis for inspection and questioning while in the field.
As is common knowledge in the pipeline industry, the best coatings always start with good surface preparation. Surface preparation in the field can be a difficult task depending on the environment and the starting condition of the pipe surface. The first obstacle to overcome when performing surface preparation in the field is the environment. Surface preparation is more than just cleaning the pipe it also includes preparing the main line coating that will be tied into as well as removing surface contaminants such as soluble salts, commonly referred to as chlorides and sulphates. Surface preparation also involves creating the proper anchor profile for the coating system that will be applied. Regardless of the details related to the coating requirements for surface preparation the resulting work will typically produce an area of bare steel which will for some duration be exposed to the elements in the environment. Environmental conditions which need to be addressed prior to performing surface preparation include monitoring the dew point, avoidance of rain or moisture in the air, possibly mitigating the wind to prevent contamination and on occasion reducing the heat exposure from the sun to create a more uniform substrate temperature. These environmental conditions are typically covered in a standard coating application course thus this paper will not dive too deep into these components; however, they are very critical and need to be addressed prior to commencing any field joint coatings.
