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Pipe Labeling Requirements for ANSI/ASME A13.1

Written by Steve Hudgik


According to ANSI/ASME A13.1, pipe markers should conform to certain requirements. The most recent update to the ANSI/ASME A13.1 code has introduced a new color scheme that specifies which colors to use for pipe labels. The code also specifies standards for the label sizes and placement.

In 2007 the ANSI/ASME A13.1 standard was updated and is now recommended for all new pipe marker applications. For facilities with existing pipe markers, it is recommended that they are updated for consistent identification.

Pipe Contents

Color Scheme

Fire-quenching fluids White text on red
Toxic and corrosive fluids Black text on orange
Flammable fluids Black text on yellow
Combustible fluids White text on brown
Potable, cooling, boiler feed, and other water White text on green
Compressed air White text on blue
User-defined White text on purple
User-defined Black text on white
User-defined White text on grey
User-defined White text on black

Standard Label Colors

The current version of the ANSI / ASME code uses a pipe labeling standards color code chart with six standard color combinations, and four user-defined combinations, as shown in the table below. The colors are based on the contents of the pipe; in general, the most hazardous feature of the contents should determine the colors used.

Pipe Label Placement

Pipe labels should be positioned so that they can be easily seen from the normal angle of approach—for instance, below the centerline of the pipe if the pipe is overhead, and above the centerline if the pipe is below eye level. Pipe labels should be placed:

  • Adjacent to all valves and flanges
  • Adjacent to all changes of direction
  • On both sides of wall or floor penetrations
  • At regular intervals on straight runs (50' is the acceptable maximum spacing, but closer spacing might be necessary for visibility.)

On many piping systems, there will be valves, actuators, and/or transmitters that can be tricky to label with adhesive pipe marking. Accessories such as Valve Tags and DuraTags can make labeling these awkward places quick and easy.

Outside Pipe Diameter (including insulation) Minimum Length of Label Color Field Minimum Letter Height
Inches mm Inches mm Inches mm
.75–1.25* 19–32 8 203 .5 13
1.5–2 38–51 8 203 .75 19
2.5–6 64–152 12 305 1.25 32
8–10 203–254 24 610 2.5 64
>10 >254 32 813 3.5 89

Label Size

Pipe diameter determines the appropriate label and text sizes, as shown in the following table.

Need help with pipe labels? Give us a call at 1-888-326-9244. Our knowledgeable customer service staff will be glad to answer your questions and help find the right labeling solution for your facility.

The information presented in this document was obtained from sources that we deem reliable; Graphic Products does not guarantee accuracy or completeness. Graphic Products, Inc. makes no representations or warranties of any kind, express or implied. Users of this document should consult municipal, state, and federal code and/or verify all information with the appropriate regulatory agency.

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