Since the 1970s, horizontal directionally drilled (HDD) crossings have become increasingly used for pipeline crossings of rivers and other obstacles. HDD crossings are now being undertaken in most soil and rock types with crossings up to 2000m in length and pipe diameters up to 48"'. Whilst HDD crossings have a predictable and short construction
schedule and in most cases are the least expensive crossing method, proper planning and design are of primary importance to the success of the crossing. The design requirements and considerations for a successful HDD crossing are examined and put into perspective based on the economics involved. Secondary factors such as selection of plant-applied and field-applied external protective coatings also play an important role. Common types of plant-applied anti-abrasion coatings used to protect the anti-corrosion coating and results from the various test methods used to relatively rank these coatings are discussed.
Keywords: directional drilling, pipeline, coating, anti-abrasion, corrosion