Steam Pipe Color Code and Labeling

The steam pipe color code varies by standard and facility. ASME A13.1 does not assign a dedicated color for steam, leaving it as a user-defined category. Most North American facilities use gray or silver for steam piping. In contrast, BS 1710 and ISO 14726 specifically assign silver-gray to steam, making it a standardized color in European and international projects.

Steam piping presents significant burn and pressure hazards, operating at temperatures from 100 to 540 degrees C (212-1004 degrees F) and pressures up to 250 bar (3,625 psi) in high-pressure systems. Clear steam pipe color coding and labeling are critical for personnel safety and operational awareness.

Steam Pipe Color Code by Standard

Standard	Color	Text Color	Steam Classification
ASME A13.1	User-defined (commonly gray/silver)	White or black	Not a named category; facility must define
BS 1710	Silver-gray (BS 4800: 10A03)	White	Dedicated steam color
ISO 14726	Silver-gray	White	Content-specific assignment
IS 2379	Silver/aluminum	Black	Dedicated steam color
AS 1345	Silver-gray	White	Consistent with ISO
DIN 2403	Red (RAL 3000)	White	Note: different from most other standards

Steam Service Types and Labeling

Industrial steam systems include multiple pressure levels, each requiring distinct labeling:

Steam Service	Typical Pressure	Typical Temperature	Common Label Text
High-pressure steam (HPS)	40-100 bar (580-1450 psi)	400-540 C (752-1004 F)	“HP STEAM” or “HPS”
Medium-pressure steam (MPS)	10-40 bar (145-580 psi)	200-400 C (392-752 F)	“MP STEAM” or “MPS”
Low-pressure steam (LPS)	1-10 bar (15-145 psi)	100-200 C (212-392 F)	“LP STEAM” or “LPS”
Steam condensate	Varies	80-180 C (176-356 F)	“CONDENSATE” or “STEAM CONDENSATE”
Exhaust steam	Near atmospheric	100-120 C (212-248 F)	“EXHAUST STEAM”

Labeling Best Practices for Steam Pipes

Steam pipe labels must be highly visible and durable. Specific considerations include:

• Insulation: Most steam pipes are insulated. Labels must be applied on the outer surface of the insulation jacket, not under it.
• Temperature resistance: Label materials must withstand the surface temperature of the insulation (typically 40-60 C / 104-140 F). Standard adhesive labels are usually adequate; high-temperature environments may require mechanical fasteners or stainless steel tags.
• Content and direction: Labels should state the service name, pressure level, and flow direction arrow.
• Placement: At all valves, steam traps, branch connections, wall penetrations, and at intervals of 7.6 m (25 ft) or less on straight runs.

Common Mistake

Using the same generic “STEAM” label for all steam pressure levels. High-pressure steam at 100 bar and low-pressure steam at 3 bar present very different hazards. Always specify the pressure level (HP, MP, LP) on the label. Maintenance personnel need to know the operating pressure before opening any valve or breaking a flanged connection.

For the complete ASME A13.1 color code chart and label sizing requirements based on pipe diameter, see the full reference guide.

Read the full guide to pipe color coding