Deep Dig

Deep dig hydrovac excavation is required when utilities or pipeline infrastructure is buried at significant depth, or when the project requires a deep foundation excavation or environmental soil sampling. Depths of 15 to 25 feet or more are achievable with properly equipped hydrovac trucks, though efficiency decreases as depth increases due to friction loss in the dig tube and the additional lift required by the vacuum system.

The primary technical challenge of deep digging is maintaining adequate vacuum at the bottom of the excavation. As the vertical distance from the dig tube tip to the vacuum inlet increases, the blower must work harder to lift the slurry. Positive displacement blowers generally outperform centrifugal blowers for deep dig applications because they maintain suction performance across a wider range of conditions.

OSHA regulations under 29 CFR 1926 Subpart P apply to all excavations, and a protective system is generally required at 5 feet and deeper. Because workers usually stay at ground level during hydrovac digging, cave-in protection is often not needed for the digging itself. Even so, the competent person on site must evaluate soil conditions and determine whether cave-in protection is needed. Workers should not enter a hydrovac excavation 5 feet or deeper without a protective system in place unless it is made entirely in stable rock, and a shallower excavation needs one too if the competent person sees signs of a potential cave-in.