Locate Ticket Discrepancy at a Brownfield Site
A contractor is preparing to excavate a 3 m deep foundation for a small addition on a former industrial site. The one-call locate request was submitted 4 business days ago. All registered members have responded except the telecommunications company, which has not marked and has not responded. The site plan shows an old 150 mm process sewer and electrical duct banks from the previous use, but these are private facilities not on the one-call system. The excavator operator reports seeing orange paint on the north edge of the site that does not match any locate drawing. The client is pressing to start because the concrete pour is booked for next week. The contractor's tolerance zone policy requires hand exposure within 1 m of any marked facility.
1. Is the contractor legally and practically clear to excavate? What must be resolved first?
Read the worked answer
No. Two separate notification problems exist. First, the telecommunication member has neither marked nor responded within the notice period; the contractor cannot treat silence as clearance. The correct step is to follow the jurisdiction's process for a non-responsive member - typically documented follow-up, a request for the member's records, and a decision on whether excavation may proceed with enhanced precautions or must wait. That decision and its basis must be documented before digging.
Second, the site is a brownfield with known private facilities (process sewer, electrical duct banks) that are not on the one-call system. One-call protection does not extend to private infrastructure; the site owner or the contractor must arrange locating of those private lines through a private locator or the owner's records. The unexplained orange paint is a red flag: orange typically indicates communications, so it may be the missing member's mark placed without a response, or it may be an unrelated mark. It cannot be ignored or assumed. The supervisor must identify who placed it and confirm it against records before relying on it. Concrete schedule pressure does not override these steps.
2. How should the tolerance zone and hand-expose policy be applied given the unknown mark and the private facilities?
Read the worked answer
The tolerance zone must be applied to every known or suspected facility, not only to facilities that appear on the one-call drawings. That means: (1) treat the unexplained orange mark as a suspected communications facility and establish a 1 m tolerance zone on both sides of it until its identity and alignment are confirmed; (2) establish tolerance zones around the private process sewer and duct banks based on the site plan, recognizing that plan accuracy on brownfield sites is often poor; (3) require hand or hydrovac exposure to confirm depth and alignment of each facility before machine excavation reaches the zone; (4) mark the tolerance zone boundaries physically and brief the operator, since paint alone is easily lost in frozen or muddy ground.
The model answer should also note that the tolerance zone policy is a minimum, not a maximum - where records are uncertain, the supervisor should widen the zone or require exposure at closer intervals. If the private facilities cannot be located with confidence, the correct judgment is to require test pitting or a private locate before the foundation excavation proceeds, and to record the decision.