Presented By
Brian McFadden

Brian McFadden

Technical writer

OSHA Safety Specialist


Webinar Preview

Contents of the Expert Pipe Marking Webinar:

  • The ANSI/ASME A13.1 Standard
  • Specialized Standards for Pipe Marking
  • Designing and Printing Pipe Labels
  • Pipe Marking and Other Programs
  • Recap and Moving Forward

Excerpt from the Expert Pipe Marking Webinar transcript:

The ANSI/ASME A13.1 Standard

The single biggest standard for labeling pipes in the United States is the ANSI/ASME A13.1 standard. It works well in a variety of applications and situations, and it’s required by OSHA for a few specific industries.

There are five major parts to the ANSI/ASME A13.1 standard:

• rules for the printed content of each label,
• sizing requirements for those labels and their text,
• the standardized color code,
• optional elements that may be added to the label,
• and rules for placing the labels in the real world.

We’ll talk about each of those parts, one at a time.

Printed Content

The most important part of any label is what the label actually says. In this standard, there are solid guidelines for the printed content of each pipe marker.

First, identify what’s in the pipe, using plain, simple, specific terms. Spell out the name of the material, if possible, but you can also use standardized abbreviations (such as “CO₂” for “carbon dioxide”). If the material’s temperature or pressure might pose a hazard, include that information as well.

Text on a pipe label should usually appear in all-caps, to be more recognizable from a distance. Use a sans-serif or “block letter” typeface, like Arial or Helvetica, rather than a serif typeface, like Times New Roman or Courier.

Next, identify the direction of the material flow with arrows. Often, these arrows will appear on both ends of a pipe label, but they can also be used on one side or the other. If the direction of flow changes, use arrows pointing in both directions.

Sizing Requirements

To maintain visibility, those printed details (and the labels they’re on) need to be sized appropriately. The A13.1 system bases its size requirements on the outer diameter (or OD) of the pipe being labeled.

For a pipe with an OD of four inches, for example, the label should be at least two inches high and twelve inches long, with the important text at least one-and-a-quarter inches tall. This chart is included in our free Best Practice Guide to Pipe Marking, so don’t worry about copying it down.

In most computer programs, the size of text is controlled in “points,” but the real-world measurements that matter are usually in inches. You can easily estimate the size of a capital letter by dividing its point size by 100 — so 24-point text will have capital letters that are about 0.24 inches high, or about a quarter inch. 200-point text will be about two inches tall. In more specialized design software, like DuraSuite from Graphic Products, you can also specify text size directly in inches.

Color Code

The color code is the most recognizable part of the A13.1 standard. The standard uses a color system based on the general type of a pipe’s contents, and the hazards that those contents pose. Other chemical safety systems use different definitions for some of these categories.

Flammable or oxidizing materials, like natural gas or many peroxides, use a yellow label with black text. The ANSI/ASME A13.1 standard defines these as the materials that pose serious fire hazards. (Oxidizing materials were added to this category in the 2015 revision of the standard.)
Combustible materials are less serious fire hazards, like canola oil, which could be a problem in a fire but aren’t likely to be a threat on their own. These materials use a brown label with white text.
Toxic or corrosive materials, like anhydrous ammonia or nitric acid, get an orange label with black text.
Fire quenching materials, like sprinkler water or CO₂ flooding systems, use a red label with white text.
Other water systems, from boilers to sanitary lines, use green labels with white text.
Compressed air systems, and other low-hazard gases like nitrogen, use blue labels with white text.
• The A13.1 color code also includes four “user-defined” colors, so you can mark special systems or unique hazards separately. These four options are purple with white text, white with black text, gray with white text, and black with white text.

This color code, directly from the standard, is the most common choice for choosing the colors of pipe markers. That said, it’s only a recommendation. The color code actually used in a given facility needs to be documented, and the affected workers need to be trained to recognize it.

While the A13.1 standard refers to the ANSI “Safety Colors” (which have specifically-defined shades), the important part is for each color to be clearly identifiable, in the real work environment.

To learn the about common types of visual signals, and practical guidance on maximizing the value of visuals in your facility, watch the full webinar on demand now!