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The Safety Brief In our podcasts we give short but valuable overviews
and insights into how contractors and safety managers
can be even more effective in protecting their workers.
In our podcasts we give short but valuable overviews and insights into how contractors and safety managers can be even more effective in protecting their workers.

Pipe Marking – ANSI Best Practices

Pipe_Marking-ANSI_Best_Practices-Creative_Safety_Supply_250x250Pipe marking can stop injuries. Labels on pipes give visual safety cues to workers on the job. Color codes from ANSI will help employees know what is inside a pipe, and if it is dangerous.

The color of the background and text of the pipe making label will quickly identify pipe contents, from potable water to toxic sludge. The facility should have a common color key posted so all workers are familiar it.

The larger the pipe, the larger the pipe marking needed. ANSI’s best practices recommendations on size are an excellent guide so employees can see the hazards even from a distance.

Pipe marking should be used at many locations, such as when a pipe turns a corner, goes through a wall, or at valve points.

These labels instantly communicate needed information for workers visually, eliminating the need for them to ask questions and increase industrial hygiene.


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Dan Clark: Hello, I’m Dan Clark of The Safety Brief. This where we talk about health and safety hazards in today’s demanding industrial and construction worksites. 

Remember this old song? “Knock three times on the ceiling if you want me, twice on the pipes if the answer is no.” But what if those pipes had contained toxic chemicals? Tony Orlando and Dawn would’ve been wise to use proper pipe markings.

Pipe marking prevents accidents. These labels provide visual identification for everyone working near pipes. Use ANSI color codes and other standard practices so workers understand pipe contents and hazards. 

There are three things to think about when pipe marking:

1. Color. ANSI A13.1 standards offer a pipe marking color scheme. It’s not mandatory, but it’s recommended to help standardize a color code. Examples:

  • White text on a red background is for fire quenching liquids.
  • Black text on orange background is more toxic for corrosive liquids.

ANSI has many other suggestions including user-defined colors like white on purple, and white on gray. Whatever you use, post a color key in a visible place in your facility.

2. Size. According to ANSI standards, the length of a label and the height of the labels lettering depend on the diameter of the pipe. A pipe with a two inch diameter must have a label that’s at least eight inches long and lettering three quarters of an inch high. That’s one example. Look at the ANSI guidelines for a complete label size chart.

3. Location. Labels have to be placed in specific locations so they’re as visible as possible to the employees. For example, you’ll want a label:

  • Every 50 feet on straight sections of pipe.
  • At all changes in direction.
  • On both sides of valves or flanges.
  • On both sides of a pipe when it goes through a wall.

A pipe marking should be readable from all angles. You may need to print lettering more than once on a label. It may also mean you place the label above or below the center of the pipe so it’s easier for the workers to read. Use arrows to indicate which direction the contents of a pipe travel.

So, there you have it. Standard pipe marking can help employees, maintenance personnel and emergency crews understand the substances in your pipes as quickly as possible.

That’s all for this episode on pipe marking. Come back for more tips and techniques on how to stay safety compliant in today’s ever-changing landscape of safety requirements. This is Dan Clark of The Safety Brief, sponsored by Creative Safety Supply. See the website at


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