What are the ANSI pipe marking guidelines
and do we have to follow them?
No, many industries have not followed the ANSI guidelines. But they can still
a useful guide to smaller firms, even as they becomes less popular with larger
firms. The ANSI pipe marker guidelines define both color codes and sizes.
| Material | Marker Color |
| Fire Quenching Materials | Red |
| Materials Inherently Hazardous | Yellow |
| Materials of Inherently Low Hazard, Gas | Blue |
| Materials of Inherent Low Hazard, Liquid | Green |
| Pipe OD Min | Pipe OD Max | Length of Color Field for Pipe Marker | Size of Letter for Legend |
| 0.75" | 1.25" | 8" | 0.5" |
| 1.5" | 2" | 8" | 0.75" |
| 2.5" | 6" | 12" | 1.25" |
| 8" | 10" | 24" | 2.5" |
| 10" | -- | 32" | 3.5" |
The problem, unfortunately, is that the modern process plant has become ever more complex and internationally "aware". To most nuclear and large international chemical firms, the traditional ANSI pipe marker designs are both superficial and outdated. Note that OSHA or an ISO 9000 audit team inspects your plant, not ANSI!
The demand, then, to put more and more information
on the pipe marker is driven by several new regulations and standards: the
EPA Standards for Clean Air, the OSHA Process Chemical Specifications and
ISO 9000 programs. Just as OSHA is changing their focus from compliance-oriented
standards to performance-oriented standards, plants are changing too. Before,
the only question was whether or not your pipes, valves and hazards were labeled
at all. Simple, one-word legends were sufficient (enough to "CYA", to put
it bluntly). Now, the questions are more complicated: (1) do your employees
actually understand potential hazards, (2) do they know how to avoid the hazard,
and most importantly (3) do they know what to do in an emergency. Passive,
single word pipe markers have been supplanted by those giving more information
and integrating into the plant's proactive hazardous communication training.
