5.19 Excavation Tolerance Zone


Practice Statement:

The excavator observes a tolerance zone that is comprised of the width of the facility plus 18 in. on either side of the outside edge of the underground facility on a horizontal plane. This practice is not intended to preempt any existing state/provincial requirements that currently specify a tolerance zone of more than 18 in.

Practice Description:

(See Practice Statement 5–20.)


  • Existing state laws, including New Mexico, Pennsylvania, South Dakota, and others
  • Telecommunications Industry Association and Electronic Industry Association (TIA/EIA), “Standard for Physical Location and Protection of Below-Ground Fiber Optic Cable Plant” (ANSI/TIA/EIA-590-A-1996)
  • American Public Works Association (APWA), “Guidelines for Uniform Temporary Marking of Underground Facilities”