Best Practice Guide

Food and Beverage Growers and Processors

Steam

Proper Maintenance

Insulation
The U.S. Department of Energy (DOE) describes three important functions of pipe insulation:

  1. Minimize risk of burns.
  2. Reduce heat loss to ambient air (also lowers HVAC cooling loads).
  3. More steam energy for end-use applications.

Insulating pipes and equipment is a low-cost method to improve the efficiency of a steam system. Check at least every five years to repair or replace deteriorated insulation. Be careful of wet insulation, particularly after rain, since it loses its insulating value and speeds deterioration, which can lead to a 5 to 10 percent loss in system capacity.

Besides pipes, insulation is recommended for equipment such as boilers, furnaces, deaerators, all lines, turbines, valves, flanges, fittings, and controls.

Steam Trap Management

Production line. Photo courtesy of S. Martinelli & Co.View Details.

A steam trap is a valve installed in steam distribution piping that bleeds off condensate and non-condensable gases without letting live steam escape. Removing condensate helps maintain the quality and quantity of "dry" steam and reduces equipment wear from saturated steam. Steam traps are installed wherever end-use equipment connects to distribution pipes, or along long stretches of pipes.

Although a steam trap is physically a small piece in any boiler-steam system, its impact is significant. Even a small leak can cost thousands of dollars each year in wasted fuel. It is common to find 15 to 20 percent of steam traps within a facility in need of repair.

Steam traps can either fail open or fail closed. If failed open, steam leaks from the system, wasting fuel and energy and reducing the amount of steam available to end-use applications by as much as five percent. A failed open steam trap can lose between 50 to 100 lb of steam per hour. If failed shut, on the other hand, condensate builds-up and reduces system capacity. More important is "water hammer," a problem in which condensate moving through distribution pipes causes damage as it "hammers" into curves, protrusions, and corners.

Fortunately, these loses can largely be prevented through routine annual maintenance of steam traps. Five useful steps in a steam trap maintenance program are:

  1. Train personnel.
  2. Locate and identify every trap. Number traps on a map, noting supply and return lines.
  3. Assess the operating condition of every trap at least annually.
  4. Develop and maintain a trap database.
  5. Respond to assessment findings.

Other Steam Leaks

Illustration courtesy of Oakridge National Laboratory.View Details.

Leaks may occur at other places along steam distribution piping, so periodic examination of pipes is a good idea. Often, leaks have an audible noise and can be visually identified.

Install and Monitor Flow Meters
Steam flow meters, as the name implies, measure the amount of steam moving from the boiler system, through the distribution system, to end-use applications. This information makes it easier to identify problems or optimize steam system performance. However, flow meters need to be regularly checked for deterioration and other problems that might affect accuracy of the readings. Steam systems, by their very nature, are a difficult environment for sensitive equipment because of high heat, high pressure, and constant moisture, all of which contribute to equipment wear and corrosion.

Business Examples

Steam is used widely throughout both facilities owned and operated by S. Martinelli & Company, and is the primary source of process heat for pasteurization. Martinelli's insulated nearly all steam lines (none were running through refrigerated areas) so that the system's thermal energy could be better conserved. Besides saving energy from operating the steam system, this measure reduces the amount of heat inadvertently released to interior spaces.


Resources

U.S. Department of Energy, Best Practices Steam program:

3E Plus - a software program to optimize the installed thickness of mechanical insulation. Helps the user determine fuel savings and emissions reductions under varying operating conditions.

Steam System Scoping Tool - a self-paced checklist for discovering steam improvement opportunities and serves as a scorecard for comparing profiles of one or more plants over time.

Steam Tip Sheets - a series of one-page reference sheets, each of which describes a specific steam improvement opportunity. Tip sheets provide a technical overview and a sample calculation of economic impacts.

Steaming Ahead - this newsletter and companion website give the steam community bi-monthly updates about program products and events.

Ensuring Energy Efficiency Through Effective Monitoring of Steam. Solartron Mobrey Ltd. Reproduced by Energy Solutions Center, Inc., Boiler Burner Consortium.

Yoder, Jesse L., Ph.D. Using Meters to Measure Steam Flow. Plant Engineering Magazine, April 1998. Reproduced by Flow Research, Inc.