ANSI Color Codes

Why are the ANSI color codes important? What does the yellow background mean?

The yellow background signifies that the piping may handle hazardous material.Unfortunately, much has changed in the typical plant over the last 70 years since thisstandard was originally conceived. The basic standard can be traced to the 1920's and use inthe US military. Obviously, our definitions for what is "hazardous" has changed. Water, air orcarbon dioxide, under certain situations (pressure, heat, mixture with other chemicals) are notalways benign. How do we interpret, for example, materials that should be used for "firequenching" that are also "hazardous"? Should we use the red or the yellow ANSI scheme?Or, how do we label a pipe that carries both the liquid (which should be green) and gas formof a chemical (which should be blue)?

Hazards, in other words, are not so easily defined. "Hazardous" may mean that the materialis hazardous to a person nearby, or to the operation of the overall plant itself. Could"hazardous" mean that the materials flowing through the process piping, if not handledcarefully, could contaminate the product. Or, if leaked into the atmosphere, could thechemical infect the environment or cause damage to employees after cumulative exposureover a period of years? Clearly, the ANSI standard was written for far simpler times.

Color Std Meaning Example

Red APWA Electric Power Lines, Cables, Conduitand Lighting Cables Buried High Voltage Line

Yellow APWA Gas, Oil, Steam, Petroleum orGaseous MaterialsNatural Gas DistributionLine

Orange APWA Communication, Alarm or SignalLines, Cables or Conduit Buried Fiber Optic Cable

Blue APWA Water, Irrigation and Slurry Lines Buried Water LineGreen APWA Sewers, Drain Line Buried Storm Sewer LineRed Traffic Prohibition STOP, YieldOrange Traffic Temporary Work Zone Construction Zone AheadYellow Traffic Caution Merge Ahead, SlowBlue Traffic Information Signs HospitalBrown Traffic Historical or Park Picnic Area AheadGreen Traffic Directional Signs Exit 1 Mile, Go

Red ANSISign Danger Signs, Highest HazardHazardous Voltage WillCause Death

Orange ANSISign Warning Signs, Medium HazardHazardous Voltage MayCause Death

Yellow ANSISign Caution Signs, Lowest HazardTurn Machine Off WhenNot In Use

Blue ANSISign Notice Signs Employees Only

Green ANSISign Safety First Signs Wear Ear Plugs

Red ANSIPipe Fire Quenching Materials Fire Protection Water

Yellow ANSIPipe Materials Inherently Hazardous Chlorine

Blue ANSIPipeMaterials of Inherently Low Hazard,Gas Compressed Air

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Green ANSIPipeMaterials of Inherently Low Hazard,Liquid Storm Drain

Blue/Red/Yellow NFPA701Blue is used for Health Hazards, Red for Flammability and Yellowfor reactivity

Variations in color-coding standards are inevitable in our complex plant and pluralistic society.While laudable, harmonization of color-codes, then, will be very difficult to achieve. Manyplants use other color-coding; for example, color-code each system (i.e. Lube Oil is brown,Condensate is green, etc.>) or color code by Unit (i.e. Unit 1 is yellow, Unit 2 is blue, etc.).For most plants, we recommend either the ANSI pipe marker color codes or simply black onyellow markers. For more complex plants, we recommend a color-coding by system. For allenvironments, we recommend the inclusion of RTK information on the valve or on the pipe.

ANSI Color Code for Thermocouple and Thermocouple Extension Wire

ANSISymbol Wire Alloys Polarity

Thermocouple WireColor

T/C Extension WireColor

Individual Jacket Individual Jacket

J IronConstantan(TM)+JP-JN

WhiteRed Brown

WhiteRed Black

K CHROMEL*ALUMEL*+KP-KN

YellowRed Brown

YellowRed Yellow

T CopperConstantan(TM)+TP-TN

BlueRed Brown

BlueRed Blue

E CHROMEL*Constantan(TM)+EP-EN

PurpleRed Brown

PurpleRed Purple

N Nicrosil(TM)Nisil(TM)+NP-NN

OrangeRed Brown

OrangeRed Orange

RSX CopperCopper Alloy+RSP-RSN - -

BlackRed Green

BX PCLW630/CopperCopper+BP-BN - -

GreyRed Grey

W3XW5X

Alloy 203; Alloy 405Alloy 225; Alloy 426

+WP-WN - -

White/RedRed White/Red

* CHROMEL and ALUMEL are registered rademarks of Hoskins Manufacturing Company. PMC Corporation reserves the right tosubstitute equivalent product to CHROMEL and ALUMEL at any time.For additional information see Bare Wire Data Sheet

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