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Specific pipe labeling, marking, and coloring regulations
Federal OSHA does not require pipes in the workplace to be labeled, marked, or colored, other than in:
However, also see information about safety color codes and sign and tag requirements for pipes later in this Frequently Asked Question.
Scheme for the identification of piping systems
It’s important to know that American National Standards Institute (ANSI) A13.1-1956, Scheme for the Identification of Piping Systems, is referenced at the following OSHA general industry regulations. Therefore, these are the only instances when the ANSI A13.1 color scheme is required by OSHA, that we know of. If you fall under these regulations, you will need to follow the 1956 edition of ANSI A13.1 when marking pipes:
If the ANSI A13.1-1956 references do not apply to your situation and your state does not have additional requirements (check your state requirements), you may wish to instead use the standards recommended by the 1996 or 2020 editions of ANSI A13.1. Both editions concern contents of pipes transporting not just liquids but also semi-liquids, gases, or fine particulates at industrial and commercial facilities, institutions, and public assembly buildings. The 2020 edition has a different color scheme than the 1996 and earlier editions.
Voluntary consensus standard ANSI A13.1-1996 suggests that pipes be identified as follows:
However, voluntary ANSI A13.1-2020 suggests pipes be identified as follows:
ANSI A13.1-1996 and ANSI A13.1- 2020 call for pipe markings to include the identity of the materials in the pipe and an arrow(s), as well as any other information to alert the marking observer to any other hazards, e.g., pressure and temperature. Adding Globally Harmonized System (GHS) product identifier, pictogram(s), signal word, and/or hazard statements is optional as part of the legend. In addition to the color and legend provisions, the standards offer legend examples, definitions, and further provisions on marking locations and intervals, marking approaches, the size and style of marking letters, marking visibility, and alternatives to the marking scheme itself.
Safety color codes
Again, other than the federal OSHA requirements mentioned earlier, pipes are not required to be color coded. However, be aware that 1910.144, Safety Color Code for Marking Physical Hazards, references safety colors yellow and red and what those colors identify or designate. With regard to piping, 1910.144 states that red shall be the basic color not only for the identification of danger but also for fire protection equipment and apparatus, i.e., sprinkler piping. So, for example, if you apply color to fire protection piping for identification, you must use red.
In addition to OSHA regulations, the voluntary consensus standard, ANSI Z535.1-1998, Safety Color Code, recommends the following color designations:
Note the 2002 and later editions of ANSI Z535.1 no longer contain the safety color meanings.
Accident prevention signs and tags
Be aware that federal OSHA 1910.145, Specifications for Accident Prevention Signs and Tags, goes over the use of DANGER, CAUTION, and other sign and tag formats. Note that: