Piping System Labeling Scheme
Reasons for Labeling
ASME standard suggests labeling all pipes, it is required for pipes to be labeled in the following situations:
- the contents of pipes could affect procedures during emergency situations
- the contents of pipes are hazardous
- the flow direction is unknown
- the destination of the contents is unknown
- the flow needs to be redirected for maintenance
- one or more valves need to be shut off for maintenance
ASME A13.1 Color Scheme
| Fluid Service | Color Combinations |
|---|---|
| Fire Quenching Fluids | Safety Red Background / White Legend |
| Toxic & Corrosive Fluids | Safety Orange Background / White Legend |
| Flammable Fluids | Safety Yellow Background / Black Legend |
| Combustible Fluids | Safety Brown Background / White Legend |
| Potable, Cooling, Boiler Feed, & Other Water | Safety Green Background / White Legend |
| Compressed Air | Safety Blue Background / White Legend |
| Defined by the User | Safety Purple Background / White Legend |
| Defined by the User | Safety White Background / Black Legend |
| Defined by the User | Safety Gray Background / White Legend |
| Defined by the User | Safety Black Background / White Legend |
ASME A13.1 Pipe Label Size
- To be read from a distance by personnel, the proper sized labels should be used.
- Pipes too small for labels should be marked with a hanging tag.
| Outside Pipe Diameter
Including Covering | Minimum Length of
Label Field Color | Minimum Height of
Letters |
|---|---|---|
| 3/4" - 1 1/4" | 8" | 1/2" |
| 1 1/2" - 2" | 8" | 3/4" |
| 2 1/2" - 6" | 12" | 1 1/4" |
| 8" - 10" | 24" | 2 1/2" |
| Over 10" | 32" |
3 1/2" |
Standards
- ASME Standards
- ASME A13.1 - Scheme for the Identification of Piping Systems