Compressed Air Pipe Color Code

The compressed air pipe color code identifies piping that carries instrument air, plant air, or utility air in industrial facilities. Under ASME A13.1, compressed air pipes use white text on a blue background (Pantone 540). Other international standards also assign blue or light blue to compressed air service, making it one of the most universally consistent color assignments across pipe marking systems.

Proper identification of compressed air piping is required for safety and maintenance. Compressed air systems operate at pressures from 6 to 10 bar (90-150 psi) in most plants, and misidentification can lead to incorrect connections, equipment damage, or personnel injury.

Compressed Air Pipe Color Code by Standard

Standard	Country/Region	Color	Text Color	Notes
ASME A13.1	United States	Blue (Pantone 540)	White	Category: non-hazardous gases
BS 1710	United Kingdom	Light blue	White	Specific to air service
ISO 14726	International	Light blue	White	Content-specific assignment
IS 2379	India	Light blue	White	Matches BS/ISO convention
AS 1345	Australia	Light blue	White	Consistent with ISO
DIN 2403	Germany	Blue (RAL 5015)	White	Content-specific

Types of Compressed Air in Piping Systems

Industrial facilities typically have multiple compressed air services, each with different quality requirements:

Air Service	Typical Pressure	Quality	Application
Instrument air (IA)	6-7 bar (90-100 psi)	Dry, oil-free, filtered	Actuating control valves, pneumatic instruments
Plant air (PA)	6-8 bar (90-120 psi)	Standard quality	Pneumatic tools, cleaning, general utility
Utility air (UA)	5-7 bar (75-100 psi)	Basic filtration	Workshop tools, tire inflation, blowdown
Breathing air	6-9 bar (90-130 psi)	Medical grade, oil-free	Respiratory protection, confined space entry

All compressed air services share the blue color code under ASME A13.1, but the label text must specify the exact service (e.g., “INSTRUMENT AIR” vs. “PLANT AIR”). Some facilities use sub-codes or additional bands to differentiate between air services.

Pro Tip

Instrument air is the most critical compressed air service in a process plant. It powers control valve actuators and pneumatic instruments. A loss of instrument air can trigger emergency shutdowns. Label instrument air pipes clearly and include flow direction arrows at every branch to help operators trace the supply path during troubleshooting. For instrument connections, see ferrule compression fittings.

Labeling Requirements

Under ASME A13.1, compressed air pipe labels must include:

• Blue background with white text stating the service name (e.g., “INSTRUMENT AIR”)
• Flow direction arrow indicating the direction of airflow
• Labels at all valves, regulators, branch connections, and wall penetrations
• Labels at intervals not exceeding 25 feet (7.6 m) on straight runs
• Minimum letter height based on pipe outside diameter (from 1/2” for small pipes to 3-1/2” for pipes over 10” OD)

Read the full guide to pipe color coding