Color  

Std  

Meaning  

Example  

Red  

APWA  

Electric Power Lines, Cables, Conduit and Lighting Cables  

Buried High Voltage Line  

Yellow  

APWA  

Gas, Oil, Steam, Petroleum or Gaseous Materials  

Natural Gas Distribution Line  

Orange  

APWA  

Communication, Alarm or Signal Lines, Cables or Conduit  

Buried Fiber Optic Cable  

Blue  

APWA  

Water, Irrigation and Slurry Lines  

Buried Water Line  

Green  

APWA  

Sewers, Drain Line  

Buried Storm Sewer Line  

Red  

Traffic  

Prohibition  

STOP, Yield  

Orange  

Traffic  

Temporary Work Zone  

Construction Zone Ahead  

Yellow  

Traffic  

Caution  

Merge Ahead, Slow  

Blue  

Traffic  

Information Signs  

Hospital  

Brown  

Traffic  

Historical or Park  

Picnic Area Ahead  

Green  

Traffic  

Directional Signs  

Exit 1 Mile, Go  

Red  

ANSI Sign  

Danger Signs, Highest Hazard  

Hazardous Voltage Will Cause Death  

Orange  

ANSI Sign  

Warning Signs, Medium Hazard  

Hazardous Voltage May Cause Death  

Yellow  

ANSI Sign  

Caution Signs, Lowest Hazard  

Turn Machine Off When Not In Use  

Blue  

ANSI Sign  

Notice Signs  

Employees Only  

Green  

ANSI Sign  

Safety First Signs  

Wear Ear Plugs  

Red  

ANSI Pipe  

Fire Quenching Materials  

Fire Protection Water  

Yellow  

ANSI Pipe  

Materials Inherently Hazardous  

Chlorine  

Blue  

ANSI Pipe  

Materials of Inherently Low Hazard, Gas  

Compressed Air  

Green  

ANSI Pipe  

Materials of Inherently Low Hazard, Liquid  

Storm Drain  

Blue/
Red/
Yellow  

NFPA 701  

Blue is used for Health Hazards, Red for Flammability and Yellow for reactivity