ASME A13.1 Scheme for the Identification of Piping Systems
Originally an American standard, later adopted in many countries either as-is or with minor variations as ANSI standard, ASME 13.1 defines in very practical ways how pipes should be marked: legend and marker sizes, suggested font, color coding, and guidelines on where to install such markers.
ASME A13.1, Color Coding principles
ASME A13.1 defines color coding based on pipe fluid classes, with 4 reserved for user defined, as follows:
| Fluid Class | Color | Sample |
|---|---|---|
Fire quenching |
Red |
FIRE FIGHTINGWhite Text On Red
|
Toxic & Corrosive |
Orange |
NITRIC ACID Black Text On Orange
|
Flammable |
Yellow |
ACETONE Black Text On Yellow
|
Combustible |
Brown |
LUBRICATING OIL White Text On Brown
|
Water |
Green |
SEA WATER White Text On Green
|
Compressed Air |
Blue |
COMPRESSED AIR White Text On Green
|
User Defined |
Violet |
OTHER 1 White Text On Violet
|
| White |
OTHER 2 Black Text On White
|
|
| Grey |
OTHER 3 White Text On Grey
|
|
| Black |
OTHER 4 White Text On Black
|
ASME A13.1, Pipe labeling Sizes
ASME A13.1 defines minimal marker width and label text letter height based on a set of pipe diameter ranges:
| Pipe OD (NPS)Outside diameter, including insulation | Marker WidthMinimum | Letter HeightMinimum |
|---|---|---|
| ¾" to 1¼" (19mm to 32mm) | 8" (200mm) | ½" (13mm) |
| 1½" to 2" (38mm to 51mm) | ¾" (19mm) | |
| 2½" to 6" (64mm to 150mm) | 12" (300mm) | 1 ¼" (32mm) |
| 8" to 10" (200mm to 250mm) | 24" (600mm) | 2 ½" (64mm) |
| Over 10" (over 250mm) | 32" (800mm) | 3 ½" (89mm) |
