Within manufacturing facilities or warehouses, different kinds of liquids, gases, and emissions are transported throughout the building via a labyrinthine network of pipes, and the obvious need to differentiate one material from another is vital to maintenance and service efforts. Pipe marking labels are the most efficient means to do this, and their effectiveness is so simple because of the quick-reference quality of color-coded pipes with clear, concise labeling text and graphics that can be easily and clearly identified at a distance. As shown in the diagram below, pipes are often at an unreachable height from workers and repair persons, so there are different size requirements for each pipe diameter. The larger the pipe, the larger the pipe markers needed.
The American National Standards Institute (ANSI) and the American Society of Mechanical Engineers (ASME), in an attempt to unify their safe workplace goals, merged their pipe marker recommendations into the ANSI/ASME 13.1 by offering a universal pipe labeling standard, and color-coded classifications for the three basic hazard categories. These standards are referenced when OSHA does an assessment following facility inspections, and are expected to be followed to the best of a facility's safety precautions and due diligence.