What is it?
Underground utility lines marked above ground with temporary paint, flags or stakes are indicated as utility locator marks. These markers are used to identify and locate underground infrastructure like electricity cables, telephone lines, fiber optics, gas pipes, water mains and sewer lines before any excavation work begins. Proper identification prevents unintended damage to underground lines and ensures worker safety.

Purpose of Utility Markers
The main purpose of utility locator marks is to communicate the presence and location of underground utility lines to contractors and construction crews working on excavation projects. It allows excavators to dig safely without risk of hitting live power lines or rupturing gas or water pipes. Accurately marked lines also prevent costly repairs and service disruptions from accidental damage. Utility owners use a standardized color-coding system with markers to identify the type of utility below.

Types of Utility Markers
The three main types of temporary above ground markers used are:

Paint: Colored spray paint is commonly used for initial identification of underground lines, especially on paved surfaces. Different colors correspond to Utility Markers types. Paint lasts a few months.

Flags: Durable plastic or fiberglass flags mounted on poles or stakes are also color coded. Flags can remain visible for longer periods, through weather and vegetation growth.

Stakes: Wooden or plastic stakes pounded securely into the ground also display color-coded utility information. Stakes require less maintenance than flags as they are wholly embedded.

In some cases, composite signs or electronic markers containing utility details may supplement basic paint, flags or stakes in high-traffic or sensitive areas. Permanent underground utility mapping through techniques like ground penetrating radar also provides precise location records.

Color-Coding of Utility Markers
A standardized color scheme adopted across North America and defined by the American Public Works Association aids quick identification:

Red: Electric power lines, cables or conduits carrying voltages of 600 volts or more.

Orange: Telecommunication lines including buried fiber optic cables or telephone lines.

Yellow: Gas, oil pipelines or ducts, or associated dangerous vapors or liquids.

Blue: Potable water supply lines, pipes or channels.

Green: Sewer lines or drain pipes.

Purple: Reclaimed water, slurry lines or irrigation systems.

Pink: Temporary survey markings.

White: Proposed excavation limits or routes.

Contractor's Responsibility for Utility Locates
Before breaking ground on jobsites, regulations usually require excavation contractors to notify local utility location services in advance and request underground utility locates. Professional locators then visit work sites using radio signal transmitters and equipment like receivers, transmitters and probes to pinpoint marks accordingly. Contractors must maintain clear and accurate utility locator marks on-site for the excavation duration as a safety precaution. They also track progress and protect exposed lines from further damage. Proper documentation and permitting when working near utilities also need to be followed.

temporary utility markers play a critical role in safely maintaining and expanding existing underground infrastructure networks. Their standardized visual language simplifies on-site identification of various utility types for excavation work. When used properly in conjunction with mandatory utility locating, markers help prevent injuries, save lives and minimize disruptions from unintended striking of energized or pressurized underground lines during construction projects. Accurate utility marking is a simple yet effective way to ensure worker and public safety in and around excavation zones.
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