When horizontal directional drilling (HDD) professionals discuss the size of an HDD rig, they usually refer to the maximum pullback force the unit can develop. The most common industry standard for a large directional drilling unit is defined as having a minimum of 100,000 pounds of pullback force. In addition to pullback, the most common specifications used to categorize HDD equipment are rotary torque of drill stem, rotation speed and the size of drill pipe.
Roger Kirwan, vice president of marketing for Vacmasters, Denver, CO, has retired after working 17 years with the company. Considered by many to be an expert in air-vacuum excavation, Kirwan spent his career at Vacmasters advising the community in the best practices when considering excavation work where underground utilities are present.