Is there a Difference Between Directional Boring and HDD?

Underground boring is a great way to avoid the common pitfalls of digging a trench: there’s little erosion; people, businesses, and infrastructure are not displaced; fewer lives are endangered in the process. It’s also growing in popularity, with the horizontal directional drilling market projected to reach $14.95 billion in four years. However, there is no one-size-fits-all underground boring system: the method you use will depend on your budget, the scale of your project, and the level of accuracy required.

The terms directional boring and horizontal directional drilling (HDD) are generally used interchangeably. Both are methods of underground drilling, or trenchless drilling, in which a pipeline is pushed through an underground hole in lieu of digging a trench. Depending on their area of expertise, directional boring contractors may use both terms to describe the same project. With that said, HDD and directional boring don’t mean the same thing, and they’ll be applied differently, depending on your project.

HDD is typically launched from the surface of the ground, and the pipeline is then steered into place above ground. This method of trenchless boring is generally used for larger projects (often 1000 feet or more). Because these pipelines are so large, and because they are installed without first creating a pit, they may be up to 100 mm off from the intended grade. Their application tends to be less expensive overall.

Directional boring may also be referred to as microtunneling. In contrast to HDD, this method is extremely precise (often within 10 mm of the intended grade). Directional boring contractors will often bore a hole using a remote-controlled laser tunneling device. This method is more expensive and time consuming than HDD, but it may be the only option if the underground soil is particularly rocky or abrasive.

Talk to directional boring contractors about their recommended techniques for your particular project. Even if they use blanket terms like “underground directional boring,” it’s important to specify how long you’ll need your pipeline to be, how accurate it needs to be, and what soil conditions you’ll be working in. High quality directional boring contractors will walk you through the process to find the right method for your project.

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