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2020 ANSI/ASME Pipe Marker Guidelines

Did you know that the standards for pipe labeling have changed? The most current standard is the ASME A13.1-2020: Scheme for the Identification of Piping Systems and it was released in late 2020. The standard establishes six requirements for the proper identification of piping systems: Marker size, letter height, color, legend (wording), directional arrow, and placement.

Comparing the new A13.1-2020 standard and the previous standard (A13.1-2015)

  • The most recent 2020 update includes new pipe diameter and letter height requirements. - See Table 1
  • A13.1-2020 now includes a guideline for marking abandoned pipes. - See here
  • A13.1-2020 continues the 2015 addition of the optional GHS (Global Harmonized System) pictograms. - See Table 4

HOW ARE MARKER SIZE AND LETTER HEIGHT DETERMINED?

The marker size and letter height are determined by the overall pipe diameter, including insulation. Marker length or color field requirements can be met by including an arrow or arrow banding tape. Letter height requirements are designed for optimum visibility on a pipe and adequate viewing distance. See Table 1 – Marker and Letter Size References.

TABLE 1: Marker and Letter Size References

Outside Diameter of Pipe Covering Length of Color Field Letter Height
0.7” - 1.3” 18 - 33 mm 8” 203 mm 0.5” 13 mm
1.4” - 2.4” 34 - 61 mm 8” 203 mm 0.7” 19 mm
2.5” - 6.7” 62 - 170 mm 12” 305 mm 1.3” 32 mm
6.8” - 10” 171 - 254 mm 24” 610 mm 2.5” 64 mm
Over 10” Over 254 mm 32” 813 mm 3.5” 89 mm

Diagram 1: Pipe Marker Layout

Diagram 1: Pipe Marker Layout

WHAT DO THE COLORS SIGNIFY?

Marker colors are for more than just looks. The colors help to easily identify the inherent danger of the piping contents. There are eleven color designations, seven standard and four user defined. See Table 2 – “Color Designations”.

Table 2: Color Designations

Fluid Service Letters & Colors
Fire Quenching Fluids LETTERS
Toxic And Corrosive Fluids LETTERS
Flammable Liquids LETTERS
Combustible Fluids LETTERS
Potable, Cooling, Boiler Feed, Other Water LETTERS
Abandoned Pipes LETTERS
Compressed Air LETTERS
Defined By User LETTERS
Defined By User LETTERS
Defined By User LETTERS
Defined By User LETTERS

HOW IS THE LEGEND DETERMINED?

The wording can be the full or abbreviated name of the system content. The standard indicates “Legends shall be brief, informative, pointed, and simple for greatest effectiveness.” The legend should have “sufficient additional details such as temperature, pressure, etc., as are necessary to identify the hazard.” - click here for standard legends list.

WHY USE DIRECTIONAL ARROWS?

Arrows are used to show the directional flow of the piping contents. If flow can be in both directions, arrows in both directions should be used. (Kolbi’s Wrap-Around Markers include arrows. Adhesive Markers comply when used with Arrow Banding Tape or Individual Arrows)

Diagram 2: Pipe Marker with arrow tape

Diagram 2: Pipe Marker with arrow tape

WHERE DO THE MARKERS GO?

Marker placement is required to assure visibility and should be positioned so that they are visible to personnel from a normal point of approach. Where pipes are located above or below the normal line of vision, the lettering should be placed above or below the horizontal centerline of the pipe. See Table 3 – “Location of Identification Markers”.

Table 3: Location of Identification Markers

DO I USE GHS PICTOGRAMS?

The use of GHS pictograms or symbols is optional. Where piping is connected to containers labeled in accordance with GHS requirements, a corresponding label which includes pictograms may be provided. See Table 4 - Standard GHS Pictograms.

 

Table 4: GHS Pictograms

WHAT ABOUT MARKING ABANDONED PIPING?

The new 2020 standard recommends marking abandoned piping left in place. These should be marked with a safety white marker with black letters and include a black border. If the piping is protected by pressurized fluid or contains residual hazardous materials, the legend should indicate that.

Kolbi Pipe Marker

Download our ANSI/ASME 2020 Guidelines

Standard Legends  

Kolbi Pipe Marker Logo - 2020

The standard legends on this page are designed to comply with the ANSI/ASME Standard A13.1 - 2020 for identification of piping systems.

LEGEND # LEGEND LEGEND # LEGEND LEGEND # LEGEND LEGEND # LEGEND
L355 110° HOT WATER RETURN L158 DISTILLED WATER L531 HEATING WATER SUPPLY L279 PROPANE GAS
L500 110° HOT WATER RETURN L161 DOMESTIC COLD WATER L532 HEATING WATER SUPPLY L280 PUMPED CONDENSATE
L361 110° HOT WATER SUPPLY L159 DOMESTIC COLD WATER RETURN L533 HIGH PRESSURE CONDENSATE L550 PUMPED CONDENSATE
L501 110° HOT WATER SUPPLY L160 DOMESTIC COLD WATER SUPPLY L534 HIGH PRESSURE CONDENSATE L282 RAIN WATER
L357 140° HOT WATER RETURN L166 DOMESTIC HOT WATER L535 HIGH PRESSURE GAS L283 REFRIGERANT
L502 140° HOT WATER RETURN L511 DOMESTIC HOT WATER L536 HIGH PRESSURE STEAM L287 REFRIGERANT LIQUID
L364 140° HOT WATER SUPPLY L175 DOMESTIC HOT WATER RECIRC L537 HIGH PRESSURE STEAM L288 REFRIGERANT SUCTION
L35 140° HOT WATER SUPPLY L512 DOMESTIC HOT WATER RECIRC L538 HOT WATER L290 RETURN
L559 ABANDONED L174 DOMESTIC HOT WATER RETURN L539 HOT WATER L35 RETURN
L100 ACID L513 DOMESTIC HOT WATER RETURN L223 HOT WATER RETURN L293 ROOF DRAIN
L503 ACID L172 DOMESTIC HOT WATER SUPPLY L540 HOT WATER RETURN L291 SANITARY DRAIN
L102 ACID VENT L514 DOMESTIC HOT WATER SUPPLY L224 HOT WATER SUPPLY L292 SANITARY SEWER
L504 ACID VENT L165 DOMESTIC WATER L541 HOT WATER SUPPLY L294 SANITARY VENT
L105 ACID WASTE L515 DOMESTIC WATER L225 HYDROGEN L295 SANITARY WASTE
L505 ACID WASTE L167 DRAIN L542 HYDROGEN L297 SNOWMELT RETURN
L111 AIR L516 DRAIN L128 INDUSTRIAL COLD WATER L298 SNOWMELT SUPPLY
L115 AMMONIA L152 DUAL TEMP RETURN L127 INDUSTRIAL HOT WATER L300 SOFT WATER
L506 AMMONIA L517 DUAL TEMP RETURN L543 INDUSTRIAL HOT WATER L303 SOLAR RETURN
L118 ARGON L157 DUAL TEMP SUPPLY L125 INDUSTRIAL WATER L304 SOLAR SUPPLY
L119 ASBESTOS FREE L518 DUAL TEMP SUPPLY L231 INSTRUMENT AIR L307 SPRINKLER
L120 BOILER BLOW DOWN L176 FILTERED WATER L232 LAB AIR L309 SPRINKLER WATER
L121 BOILER FEED WATER L519 FIRE DAMPER L234 LAB VACUUM L316 STEAM
L122 CARBON DIOXIDE L520 FIRE PROTECTION L230 LAB VENT L551 STEAM
L507 CARBON DIOXIDE L180 FIRE PROTECTION WATER L544 LAB VENT L317 STEAM CONDENSATE
L124 CARBON DIOXIDE L181 FIRE SPRINKLER WATER L233 LAB WASTE L552 STEAM CONDENSATE
L131 CHILLED WATER L188 FUEL OIL L545 LAB WASTE L310 STEAM RETURN
L35 CHILLED WATER RETURN L185 FUEL OIL RETURN L238 LOW PRESSURE CONDENSATE L319 STEAM SUPPLY
L129 CHILLED WATER SUPPLY L186 FUEL OIL SUPPLY L546 LOW PRESSURE CONDENSATE L553 STEAM SUPPLY
L133 CHLORINE L189 GAS L240 LOW PRESSURE STEAM L313 STORM DRAIN
L508 CHLORINE L521 GEOTHERMAL WATER RETURN L547 LOW PRESSURE STEAM L314 STORM SEWER
L134 CITY WATER L522 GEOTHERMAL WATER SUPPLY L246 MAKE-UP WATER L315 STORM WATER
L137 COLD WATER L191 GLYCOL L247 MEDICAL AIR L320 SUMP PUMP DISCHARGE
L135 COLD WATER RETURN L523 GLYCOL L249 MEDIUM PRESSURE CONDENSATE L321 SUPPLY
L136 COLD WATER SUPPLY L190 GLYCOL RETURN L250 MEDIUM PRESSURE STEAM L554 SUPPLY
L138 COMPRESSED AIR L524 GLYCOL RETURN L548 MEDIUM PRESSURE STEAM L328 TEMPERED WATER
L139 COMPRESSED AIR L195 GLYCOL SUPPLY L255 NATURAL GAS L555 TEMPERED WATER
L142 CONDENSATE L525 GLYCOL SUPPLY L256 NATURAL GAS 2 PSI L326 TOWER WATER
L509 CONDENSATE L201 HEAT PUMP RETURN L258 NITROGEN L324 TOWER WATER RETURN
L143 CONDENSATE DRAIN L202 HEAT PUMP SUPPLY L259 NITROGEN L325 TOWER WATER SUPPLY
L35 CONDENSATE DRAIN L208 HEATING HOT WATER RETURN L260 NITROUS OXIDE L329 VACUUM
L103 CONDENSATE RETURN L526 HEATING HOT WATER RETURN L262 NON-POTABLE WATER L556 VACUUM
L510 CONDENSATE RETURN L210 HEATING HOT WATER SUPPLY L549 NON-POTABLE WATER L331 VENT
L145 CONDENSER WATER RETURN L527 HEATING HOT WATER SUPPLY L560 NON-POTABLE WATER L557 VENT
L146 CONDENSER WATER SUPPLY L204 HEATING RETURN L266 OXYGEN L332 WASTE
L147 CONDENSER WATER L528 HEATING RETURN L267 PLANT AIR L558 WASTE
L150 COOLING WATER L207 HEATING SUPPLY L268 POTABLE COLD WATER L334 WASTE
L148 COOLING WATER RETURN L529 HEATING SUPPLY L269 POTABLE HOT WATER L336 WASTE WATER
L149 COOLING WATER SUPPLY L211 HEATING WATER RETURN L273 POTABLE WATER L339 WATER
L153 DEIONIZED WATER L530 HEATING WATER RETURN L276 PROCESS WATER L340 WELL WATER