Made the same day New: paste your valve schedule, get every tag priced and a printable valve chart Make a valve chart

Valve identification tags

Valve identification tags are usually color-coded to match the pipe markers on the same line: green with white letters for water, yellow with black for flammable fluids such as gas and steam, red with white for fire protection, blue with white for compressed air. Those pairs come from ASME A13.1, the US scheme for identifying piping.

The color code, by service

Each row is a color group with the services the builder files under it. Purple, grey, black and white pairs are left for you to assign.

ColorASME A13.1 groupWhat goes in itCommon abbreviations
ARed / whiteFire quenchingSprinkler and fire-fighting fluidsSPR, FP, SP
AOrange / blackToxic & corrosiveAcids, caustics, chemical feedCF, ACID, CAUS
AYellow / blackFlammableGas, and by custom steam and refrigerantLPS, MPS, HPS, CR, RL, RS, RHG, GAS, LPG
AMedium Brown / whiteCombustibleOils and fuelsFO, DF, LO, HO
AGreen / whiteWaterPotable, cooling, boiler feed and other waterDCW, DHW, DHWR, NPW, MUW, BFW, HWS, HWR, CHWS, CHWR, CWS, CWR, GS, GR, SAN, ST, CD
ABlue / whiteCompressed airCompressed air and vacuumCA, VAC
APurple / whiteUser definedAssign to your own services—
ASmoke Grey / whiteUser definedAssign to your own services—
ABlack / whiteUser definedAssign to your own services—

What the standards say

ASME A13.1 sets the scheme for identifying piping systems — colors, legends and arrows on pipe markers. Its published scope is piping. Using the same colors on valve tags is the common practice, so a valve reads the same as the pipe it isolates.

CAN/CGSB-24.3 is the Canadian piping identification standard. It has been withdrawn, but many Canadian project specifications still cite it. Its classes are broader: yellow for hazardous contents, green for low-hazard liquids, blue for low-hazard gases, red for fire protection. The builder can color by either scheme.

Your specification decides. Division 22 and 23 identification sections often set the tag size, the letter heights and the fastening. Follow them; the builder’s spec check helps.

Color is never the only cue. Engrave the abbreviation too, so the tag still reads for anyone who can’t tell the colors apart.

Canada vs US at a glance

ServiceASME A13.1CGSB 24.3
DCW Domestic cold waterAGreenAGreen
HWS Heating water supplyAGreenAYellow
CHWS Chilled water supplyAGreenAGreen
LPS Low pressure steamAYellowAYellow
GAS Natural gasAYellowAYellow
CA Compressed airABlueABlue
SPR SprinklerARedARed
FO Fuel oilAMedium BrownAYellow
ACID AcidAOrangeAYellow

How the builder files each service. Check your project specification before ordering.

Common valve tag abbreviations

Type any of these on the top line in the builder and the tag colors itself.

AbbreviationServiceGroupASME A13.1 color
DCWDomestic cold waterWaterAGreen / white
DHWDomestic hot waterWaterAGreen / white
DHWRDomestic hot water recircWaterAGreen / white
NPWNon-potable waterWaterAGreen / white
MUWMake-up waterWaterAGreen / white
BFWBoiler feed waterWaterAGreen / white
HWSHeating water supplyHeating & coolingAGreen / white
HWRHeating water returnHeating & coolingAGreen / white
CHWSChilled water supplyHeating & coolingAGreen / white
CHWRChilled water returnHeating & coolingAGreen / white
CWSCondenser water supplyHeating & coolingAGreen / white
CWRCondenser water returnHeating & coolingAGreen / white
GSGlycol supplyHeating & coolingAGreen / white
GRGlycol returnHeating & coolingAGreen / white
LPSLow pressure steamHeating & coolingAYellow / black
MPSMedium pressure steamHeating & coolingAYellow / black
HPSHigh pressure steamHeating & coolingAYellow / black
CRSteam condensateHeating & coolingAYellow / black
RLRefrigerant liquidHeating & coolingAYellow / black
RSRefrigerant suctionHeating & coolingAYellow / black
RHGRefrigerant hot gasHeating & coolingAYellow / black
GASNatural gasGas & airAYellow / black
LPGPropaneGas & airAYellow / black
CACompressed airGas & airABlue / white
VACVacuumGas & airABlue / white
SPRSprinklerFireARed / white
FPFire protection waterFireARed / white
SPStandpipeFireARed / white
SANSanitary drainDrainageAGreen / white
STStorm drainDrainageAGreen / white
CDCondensate drainDrainageAGreen / white
FOFuel oilOil & chemicalAMedium Brown / white
DFDiesel fuelOil & chemicalAMedium Brown / white
LOLube oilOil & chemicalAMedium Brown / white
HOHydraulic oilOil & chemicalAMedium Brown / white
CFChemical feedOil & chemicalAOrange / black
ACIDAcidOil & chemicalAOrange / black
CAUSCausticOil & chemicalAOrange / black

Color-coded tags for every service

Paste your schedule and each tag takes the color of its service. Override any of them.

Build your tagsMake a valve chart

Questions

What color is a gas valve tag?
Yellow with black letters in the ASME A13.1 scheme, which groups gas with other flammable fluids.
What color is a water valve tag?
Green with white letters for potable, cooling, boiler feed and other water in the ASME A13.1 scheme.
What color are fire sprinkler valve tags?
Red with white letters, the A13.1 color for fire-quenching fluids. Check the identification your authority having jurisdiction asks for on sprinkler valves.
Does ASME A13.1 require valve tags?
Valve tags are usually required by the project specification rather than by A13.1, whose published scope is piping. Specs often borrow A13.1’s colors for the tags.
What color is steam on a valve tag?
Yellow with black letters in A13.1, which treats steam as hazardous because of its temperature and pressure.