Insulate Steam Pipes |

Insulate Steam Pipes


Uninsulated steam distribution and condensate return lines are a constant source of wasted energy. Insulation can typically reduce energy losses by 90% and help ensure proper steam pressure at plant equipment. Any surface over 120°F should be insulated, including boiler surfaces, steam and condensate return piping, and fittings.

Insulation frequently becomes damaged or is removed and never replaced during steam system repair. Damaged or wet insulation should be repaired or immediately replaced to avoid compromising the insulating value. Eliminate sources of moisture prior to insulation replacement. Causes of wet insulation include leaking valves, external pipe leaks, tube leaks, or leaks from adjacent equipment.



Example: In a plant where the value of steam is $4.50/MMBtu, a survey of the steam system identified 1,120 feet of bare 1-inch diameter steam line, and 175 feet of bare 2-inch line both operating at 150 psig. An additional 250 feet of bare 4-inch diameter line operating at 15 psig was found. From the table, the quantity of heat lost per year is:

1-inch line: 1,120 feet x 285 MMBtu/yr per 100 ft = 3,192 MMBtu/yr

2-inch line: 175 feet x 480 MMBtu/yr per 100 ft = 840 MMBtu/yr

4-inch line: 250 feet x 415 MMBtu/yr per 100 ft = 1,037 MMBtu/yr

Total Heat Loss = 5,069 MMBtu/yr

The annual operating cost savings from installing 90% efficient insulation is:

0.90 x $4.50/MMBtu x 5,069 MMBtu/yr = $20,530

More Information

Insulate Fittings


Ceramic Insulation

DOE Software

3E Plus Version 3.2

The program calculates the most economical thickness of industrial insulation for user input operating conditions. You can make calculations using the built-in thermal performance relationships of generic insulation materials or supply conductivity data for other materials.

You can get help on software installation and operation from the EERE Information Center at 1-877-EERE-INF (877-337-3463 FREE) or email

Go to the web site at

Source:  DOE “Improving Steam System Performance: A Sourcebook for Industry” 2004; image of pipe insulation from 4/2005;