Nighttime issues and considerations in horizontal directional drilling operations

Horizontal Directional is trenchless construction method that Drilling (HDD) a enables the installation of underground utilities with minimal disruption to the surface. With increased considerations for environmental awareness, safety, and social cost savings to the general public, HDD applications have increased over the past decade with over 10,000 drill rigs in operation today worldwide. The majority of installations occur during normal working daylight hours; however, often situations arise necessitating the need for nighttime installations. These include scheduled operations in which long bore lengths where maintaining circulation of drilling fluids is paramount and situations where operational problems necessitate unscheduled workday extensions. This paper describes issues and considerations that must be addressed when attempting to employ the HDD method during nighttime conditions. These include: 1) worker safety; 2) public safety; 3) quality of work; 4) monitoring of performance; 5) delivery of supplies and material; 6) inspection; and 7) worker fatigue and morale. The paper concludes with a recent case history involving a nighttime installation.