an outer duct for roadside utilities. Worksafe encourages the use of a 5mm wide or larger colored stripe to indicate the content of the black duct using one of the color codes above. A plain black microduct or 2-pair telephone cable is often used by Chorus for premises drop cables. |} United Kingdom The national standard for the United Kingdom uses the following color guide: {| class="wikitable" |style="background:red; color:white" | Red |electric power lines, conduit, and cables |- |style="background:orange; color:black" | Orange |telecommunication, alarm or signal lines |- |style="background:yellow; color:black" | Yellow |gas, oil, steam, petroleum, or other flammable material |- |style="background:green; color:white" | Green |sewage and drain lines |- |style="background:blue; color:white" | Blue |drinking water |- |style="background:purple; color:white" | Purple |reclaimed water, irrigation, and slurry lines |- |style="background:pink; color:black" | Pink |temporary survey markings, unknown/unidentified facilities |- |style="background:white; color:black" | White |proposed excavation limits or route |} United States and Canada Canada and the United States use the American Public Works Association (APWA) Uniform Color Codes for temporary marking of underground utilities: {| class="wikitable" |style="background:red; color:white" | Red |electric power lines, cables, conduit, and lighting cables |- |style="background:orange; color:black" | Orange |telecommunication, alarm or signal lines, cables, or conduit |- |style="background:yellow; color:black" | Yellow |natural gas, oil, steam, petroleum, or other gaseous or flammable material |- |style="background:green; color:white" | Green |sewers and drain lines |- |style="background:blue; color:white" | Blue |drinking water |- |style="background:purple; color:white" | Purple |reclaimed water, irrigation, and slurry lines |- |style="background:pink; color:black" | Pink |temporary survey markings, unknown/unidentified facilities |- |style="background:white; color:black" | White |proposed excavation limits or route |} Some municipalities use pink paint to make lines and codes on the pavements related to required street improvements such as ramp replacement, asphalt grinding, and form injection. These markings are not directly related to utility location. See also Dynatel, a product line of utility locators and markers Subsurface utility engineering Underground Service Alert Utility tunnel – an alternative method of routing underground utility lines and services References Technology Transfer Information Center. "Statement of Need: Utility Locating Technologies". Accessed October 31, 2007. Jaufer, Rakeeb M., Amine Ihamouten, Yann Goyat, Shreedhar S. Todkar, David Guilbert, Ali Assaf, and Xavier Dérobert. 2022. "A Preliminary Numerical Study to Compare the Physical Method and Machine Learning Methods Applied to GPR Data for Underground Utility Network Characterization" Remote Sensing 14, no. 4: 1047. https://doi.org/10.3390/rs14041047 External links American Public Works Association, an organization