The accident: Crews started working on a gas station renovation in an older residential section of a small town. The plans called for a new water run-off drainage line to be installed from the existing structure to a nearby sewer, but there were no existing prints of the service station’s original utility lines. A worker using a horizontal directional drill to bore under the sidewalk hit a low-voltage electric line, cutting power to the station and adjacent stoplights. The drill operator was hospitalized and lost five work days from injuries sustained in the accident.
The bottom line: Horizontal drilling safety begins long before the actual drilling starts. Follow these procedures to avoid personal injuries and disruption of electrical service.
Start the day with a tailgate safety meeting to discuss the hazards of the day. Discuss your company’s emergency response procedures. The entire crew should walk the jobsite to identify obstacles and utilities specified by the local One-Call System.
Post contact information for emergency services (911), Call-One, the electric company and your company in a convenient location with a cell phone, land line or radio immediately available. Designate a competent person who has the authority to deal with emergencies.
You and your drill operator should walk the planned drill path with a trained locating equipment technician to locate hazards or unmarked utilities that may be missed by One-Call or in a visual inspection. Use the tracking receiver to find signal strength variations or other unusual readings and mark these locations.
Discuss what actions the planned drill path requires. Know the exact drilling entry point, how deep the operator will be drilling, where the exit pit is, what soil classifications you are working with and site conditions. Make sure you have enough clearance from all obstacles for the back reamer.
Establish communications procedures between the tracking operator and the drill operator. Make sure both agree on radio protocol like confirming all messages, and understand all visual signals and acknowledgments. The tracking operator and drilling operator must stay in communication at all times.
Make sure the drill operator has read the operator manual for the drilling machine in use and is familiar with its safety features.
Verify your position frequently and if you encounter an unexpected or inconsistent reading, stop drilling! Cross check all of your information sources and do not continue drilling until you identify and correct the problem.
Practice good pit safety. Shore up trench walls and keep spoils more than 2 feet from the edge of the pit.
Information for this Safety Watch was gathered from OSHA (www.osha.gov), the Association of Equipment Manufacturers (www.aem.org) and the Construction Safety Council (www.buildsafe.org). It is intended for general information purposes only.