In steam systems that have not been maintained for three to five years, between 15 percent to 30 percent of the installed steam traps may have failed - thus allowing live steam to escape into the condensate return system. In systems with a regularly scheduled maintenance program, leaking traps should account for less than 5 percent of the trap population. If your steam distribution system includes more than 500 traps, a steam trap survey will probably reveal significant steam losses.


In a plant where the value of steam is $10.00 per thousand pounds ($10.00/1,000 lb), an inspection program indicates that a trap on a 150-pound-per-square-inch-gauge (psig) steam line is stuck open. The trap orifice is 1/8 inch in diameter. The table shows the estimated steam loss as 75.8 pounds per hour (lb/hr). After the failed trap is repaired, annual savings are:

Annual Savings = 75.8 lb/hr x 8,760 hr/yr x $10.00/1,000 lb = $6,640


Steam traps are tested to determine if they are functioning properly and not cold plugging or failing in an open position and allowing live steam to escape into the condensate return system. There are four basic ways to test steam traps: temperature, sound, visual, and electronic.


• High-Pressure (150 psig and above): Weekly to Monthly

• Medium-Pressure (30 to 150 psig): Monthly to Quarterly

• Low-Pressure (below 30 psig): Annually

Suggested Actions

Steam traps are tested primarily to determine whether they are functioning properly and not allowing live steam to blow through.

• Establish a program for the regular systematic inspection, testing, and repair of steam traps.

• Include a reporting mechanism to ensure thoroughness and to provide a means of documenting energy and dollar savings.


U.S. Department of Energy (DOE)- DOE’s software, theSteam System Assessment ToolandSteam System Scoping Tool, can help you evaluate and identify steam system improvements. In addition, refer toImproving Steam System Performance: A Sourcebook for Industryfor more information on steam system efficiency opportunities.

Visit the BestPractices Website at to access these and other energy efficiency resources.

Reprinted from Steam Tip Sheet #1, “Inspect and Repair Steam Traps,” from the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy. For more information, visit

Publication date:04/05/2010