Pipe Marking and Color Code Chart

What it is

ASME A13.1 sets a uniform way to identify the contents of piping. Each marker shows the name of the contents in words and a flow arrow, on a background color that shows the hazard group. The words are the main identifier. The color is a quick visual cue. Since the 2007 edition, the scheme has six standard color groups plus four colors the user can define.

How to read it

1. Read the legend for the contents.
2. Read the background and text color to see the hazard group.
3. Follow the arrow for the flow direction.
4. Check the site legend for any user-defined colors.

Color scheme

Legend size by pipe OD

Key points

• Place markers next to valves and flanges, at changes in direction, where pipes pass through walls or floors (both sides), and at regular intervals on straight runs.
• Place markers where they can be seen from the normal working position, often below the pipe centerline on overhead runs.
• Size the marker to the OD of the insulation, not the bare pipe, on insulated lines.
• Pipe smaller than 3/4 in OD can use a tag instead of a wrap marker.
• Some industries and sites add their own color rules. Follow the site's written scheme.

Common mistakes

• Using color alone with no legend.
• Leaving off the flow arrow.
• Sizing markers to the pipe and not the insulation.
• Using the pre-2007 color scheme on new work without checking the site standard.

Governing standards: ASME A13.1 (scheme for the identification of piping systems).

Reference only. Verify against the current governing code or standard, the manufacturer's data and the project documents before use. Apps for Distributors disclaims liability arising from reliance on this reference.