What does a yellow pipe label mean?

The color of a pipe label is one of the most important aspects of pipe identification. The reason being because color has the ability to be seen from a far distance rather than text or symbols that require employees or visitors to approach the pipe to be able to identify its contents. With that being said, text and symbols are a more specific identification tool within pipe labeling systems. Think of it as a funnel beginning with a broad category of color identifiers that eventually gains more and more specificity as information is added.

Color Codes for Pipes

Pipe color code standards can be found in the ANSI/ASME A13.1 standard which is enforced by OSHA with the help of incorporation by reference laws. The color yellow specifically is used with black lettering to denote the presence of flammable and oxidizing liquids and gases. Some examples of those could be anything from gasoline, oil, natural gas, propane, and even chlorine.

As one can imagine, pipes labeled with yellow contain chemicals that pose a serious threat to employees if a pipe bursts or the wrong valve is opened. This is the primary reason why pipe marking is incredibly important regarding workplace safety. A recognizable color scheme allows for employees to identify the general properties of a substance. Not only that, but the pipe markings allow emergency personnel to give the appropriate care to those who were injured and also helps them determine the next best course of action for preventing more property damage. 

Using the correct color is essential for communication purposes. If a pipe should be marked as yellow for oxidizing and flammable, labeling it green incorrect as that color denotes the presence of a water source. Misidentification of substances due to incorrect labeling can be life-threatening, which is why it is important to be familiar with the ANSI/ASME 13.1 standard.