Materials Performance is the world's most widely circulated magazine dedicated to corrosion prevention and control. MP provides information about the latest corrosion control technologies and practical applications for every industry and environment.
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40 AUGUST 2017 MATERIALS PERFORMANCE NACE INTERNATIONAL: VOL. 56, NO. 8 COATINGS & LININGS I Horizontal directional drilling is in- creasingly being used to install sec- tions of pipe across many spans that are considered high consequence areas. While regulation currently calls for extra consideration to be given to the coatings used to protect these sections of pipe from corrosion, the systems currently being employed may be insufficient. Cathodic protec- tion systems and casings shouldn't be a substitute for an intact coating sys- tem. Fiber-reinforced urethane abra- sion-resistant overcoat systems can be employed to ensure the damage to the coating done by these types of installations is reduced or eliminated. In our mo d ern w orl d , n e w pip elin e installation is a constant, and nearly every one being constructed has some portion that will be installed using horizontal di re c t i o n a l d r i l li n g ( H D D ) . H D D h a s b e c o m e a v it a l p a r t of n e w pi p e li n e construction and there are many reasons for its acceptance. W hen a pipeline is installed by HDD or microtunneling, it is done so because an obstruction is in the way that must remain undisturbed, such as a road, lake, building, railroad, or river. HDD has gained popularity because the pipe cannot be trenched into the ground in these areas the same way it is over stretches of open land. While HDD-installed pipe accounts for <10% of new construction, it could possibly represent the most crucial 10% that should be protected. The ver y reasons why these vital sections should be protected are the same reasons that trench- less technolog y is used—the pipes run b e n e a t h o u r r o a d s , l a k e s , b u i l d i n g s , railroads, and rivers. Typically, these are cl a ssi f i e d a s hi g h c on s e qu en c e a re a s (HCAs). What is being done to ensure these pipelines are as safe as possible in these HCAs? While investigating that question, many discussions were held with integrity engineers and pipeline operators to evalu- ate their methods and decision-making cri- teria. Nearly all the respondents, at some point, reference the guidelines provided by the U.S. Code of Federal Regulations (CFR) Title 49, Parts 192 and 195 as they relate to their field. 1-2 The objective was to deter- mine if enough was being done to ensure the primary corrosion barrier was in place after the pipe was installed. Because HDD installation methods expose pipeline coat- ings to the most aggressive situations a coating might experience, it is imperative that all methods are utilized to ensure the coating is protected during installation. Conducting inspections or performing re p a i r s t h a t w o u l d ty p i c a l ly re q u i re un ear thin g th e pip e are not p o ssi bl e. Implementing the most proven technology available ensures a coating will remain intact in these inaccessible areas where spot repairs are not reasonably feasible. Guidance In reviewing the CFR regarding coat- ings and corrosion control, Parts 192 and 195 very closely mirror one another. In gen- eral, they both say that new pipelines must have a coating used for corrosion control and it must work with the cathodic protec- The Hidden Damage Done to Protective Coatings r on r . r aphoon, NRI Neptune Research, Inc., Riviera Beach, Florida, USA