Orange - Communication, alarm or signal lines, cables or conduit
Pink - Temporary survey markings
Red - Electric power lines, cables, conduit, and lighting cables
White - Proposed excavation
Yellow - Gas, oil, steam, petroleum or gaseous materials
Guidelines for Uniform Temporary Marking of Underground Facilities
This marking guide provides for universal use and understanding of the temporary marking of subsurface facilities to prevent accidental damage or service interruption by contractors, utility companies or any others working on or near those underground facilities.
Use of Markings
Use color-coded surface marks (paint or similar coating) to indicate the location and route of buried lines. To increase visibility, color-coded vertical markers (temporary stakes or flags) should supplement surface marks. All marks and markers should indicate the name, initials or logo of the company that owns or operates the line and the width of the facility if it is greater than 50 millimeters (2 inches). If the surface over the buried line is to be removed, supplemental offset markings may be used. Offset markings should be on a uniform alignment and must clearing indicate that the actual facility is a specific distance away.
Location Tolerance Zone
Any excavation within the tolerance zone should be performed with hand tools until the marked facility is exposed. The width of the tolerance zone may be specified in law or code. If not, 500 millimeters (18 inches) is required from each side of the facility. The tolerance zone includes the width of the facility and 500 millimeters (18 inches) measured horizontally from each side of the facility.
Use white marks to show the location or boundary of proposed excavation. Surface marks on roadways should not exceed 40 millimeters by 500 millimeters (1.5 inch by 18 inches). The facility color may be added to white flags or stakes.
One-call damage prevention systems should be contacted prior to excavating to prevent damage to buried facilities.
Adopt Uniform Color Code
The American Public Works Association encourages public agencies, utilities, contractors, other associations, manufacturers and all others involved in excavation to adopt the ULCC Uniform Color Code using ANSI standard Z53.1 safety colors.