As onshore pipeline rights-of-way become more congested and urban sprawl increases, the number of horizontal directional drills (HDDs) will likely increase. HDD is a trenchless pipeline installation method that requires drilling a larger pilot hole where the mainline pipe can be subsequently pulled through the drilled hole. However, HDDs have an increased probability for coating damage, even when coated with traditional mill or field applied abrasion resistant overcoat (ARO). This coating damage includes abrasion, impact, gouging, denting, tearing, bending, etc. and that damage may exist for the life of the pipeline due to an HDD being inaccessible for future maintenance.
Product Number:
51322-17633-SG
Author:
David B. Futch, Tré Bischof, David D’Ambrosio, Chris Alexander
Publication Date:
2022
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As onshore pipeline rights-of-way become more congested and urban sprawl increases, the number of horizontal directional drills (HDDs) will likely increase. HDD is a trenchless pipeline installation method that requires drilling a larger pilot hole where the mainline pipe can be subsequently pulled through the drilled hole. However, HDDs have an increased probability for coating damage, even when coated with traditional mill or field applied abrasion resistant overcoat (ARO). This coating damage includes abrasion, impact, gouging, denting, tearing, bending, etc. and that damage may exist for the life of the pipeline due to an HDD being inaccessible for future maintenance. Therefore, there remains a need for a high quality, sacrificial overcoat to protect the underlying coating, both on the mainline and field joints.
This paper details the development of a new moisture-cured urethane ARO to provide protection within an HDD installation. Traditional laboratory test methods referenced in AMMP (formally NACE), CSA, or ASTM examines a coating product on a wide range of material properties on a subscale level. While the coupon-level laboratory abrasion and gouging test provides a good sub-scale metric, they are not truly representative of the gouging risk that exists when a pipeline is being pulled through an HDD. To address the shortcomings of the sub-scale testing regimen, a comprehensive full-scale test program was developed and executed to compliment the sub-scale test results to demonstrate the ability of the developed ARO to resist damage when subjected to an array of gouging instruments and loading conditions. These results provide the end user with a more representative test set to gain confidence when choosing the appropriate product to provide protection during an HDD.
