These guidelines are based on industry specifics and its country specification where they are applied. The guidelines will help to ensure proper deployment of the markings for your infrastructure when correctly applied.
The guidelines for pipe marking are based on 4 main areas:
- Format of the standard used
- Color schemes based on pipe application
- Text height based on the required pipe size
- Visibility based on the infrastructure
Pipe Markers Formats

Pipe Marker Color Recommendation
Guidelines taken from ASME (ANSI) Standard A13.1 – 2007

Text Height
Text height and marker’s length recommendation with reference to outer diameter of pipe (ASME)

Pipe Outer Diameter | Height of Letter | Marker’s Length | |||
Inch | mm | Inch | mm | Inch | mm |
0.75 – 1.25 | 19 – 32 | 0.5 | 13 | 8 | 200 |
1.5 – 2 | 38 – 51 | 0.75 | 19 | 8 | 200 |
2.5 – 6 | 64 – 150 | 1.25 | 32 | 12 | 300 |
8 – 10 | 200 – 250 | 2.5 | 64 | 24 | 600 |
> 10 | > 250 | 3.5 | 89 | 32 | 800 |
Visibility of Pipemarkers based on Piping Flow Direction
Pipes should be identified using pipe markers in the following cases, with arrows indicating the direction of flow
Case 1: Pipes should be marked adjacent to all valves and flanges

Case 2: Pipes should be marked adjacent to change in directions

Case 3: Pipes should be marked at both sides of the floor or wall penetrations

Case 4: Pipes should be marked every 25’ to 50’ interval on straight runs

Case 5: Pipe markers should be located in positions such that they are readily visible to personnel in the facility from the point of normal approach
