Colour-coding
Utility color codes are used for identifying existing underground utilities in construction areas with the intent of protecting them from damage during excavation.
Public utility systems are often run underground; some by the very nature of their function, others for convenience or aesthetics. Before digging, local governments often require that the underground systems' locations be denoted and approved, if it is to be in the public right-of-way.
Colored lines at and/or flags are used to mark the location and denote the type of underground utility. A special type of spray paint, which works when the can is upside-down, is used to mark lines, often in a fluorescent color. On flags, a logo often identifies the company or municipal utility which the lines belong to, or an advertisement for a company which has installed an irrigation system for lawns or gardens. In this case, each sprinkler head is usually marked, so that landscaping crews will not cover or bury them with soil or sod, or damage them with tractors or other construction equipment while digging holes for trees, shrubs, or other large plants or fenceposts. This is also important because a vehicle (tractor, truck, or otherwise) can break a sprinkler or the hard-PVC pipe or joint it is mounted on simply by driving over it, particularly on newly-moved soil which is uncompacted and therefore unsupportive of such weight.
The American Public Works Association (APWA) Uniform Color Codes for temporary marking of underground utilities are listed below:
Red | electric power lines, cables, conduit, and lighting cables |
Orange | telecommunication, alarm or signal lines, cables, or conduit |
Yellow | natural gas, oil, steam, petroleum, or other gaseous or flammable material |
Green | sewers and drain lines |
Blue | drinking water |
Purple | reclaimed water, irrigation, and slurry lines |
Pink | temporary survey markings, unknown/unidentified facilities |
White | proposed excavation limits or route |
Read more about this topic: Utility Location