| Source Newsletter 2008 issue 1 |
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Steam Trap Testing Can Lead to Big Savings
While steam trap testing and repair should always be on a facility’s maintenance to-do list, many facilities do not conduct adequate monitoring to minimize steam leaks. Testing steam traps for leaks requires some knowledge of steam systems and a familiarity with the test equipment required. Facility staff may not feel comfortable conducting their own trap inspections using the sophisticated test equipment. Subcontracting the trap testing may require bringing in expertise from outside the local area, thereby increasing costs to the company. For these reasons, trap maintenance is often ignored.
However, there is a large potential for energy savings when a facility inspects and maintains steam traps. This is the number one best practice listed in the Department of Energy’s (DOE) Steam Tip Sheets. The challenge to achieving savings is for companies to implement an appropriate maintenance program to detect trap leaks and repair them as soon as possible. In most instances, the leak is not visible and the steam system continues to run with no immediate indication of a failure.
Testing methods and frequencies vary
As part of the steam trap testing initiative, MnTAP educated facilities on the steam trap testing methods and frequencies, and provided assistance to companies seeking utility rebates for steam trap testing technology. While the methods can vary largely in cost and effort required, any testing method can be effective if used correctly and as often as recommended by the DOE.
Manual inspections can be a cost-effective way to inspect steam traps. Recognizing a leak immediately and repairing or replacing problematic steam traps will likely result in energy and cost savings. Facilities that follow DOE recommendations should see trap leak rates of less than 5% and minimized cost of the leaks because the inspection frequency is adequate. However, if the cost of manual inspections becomes too high or the recommended inspection frequency of inspections cannot be maintained, leak rates and costs will increase and may justify the installation of a testing technology such as the SteamEye system, which has the lowest expected trap leak rate.
While more costly than manual inspections, the SteamEye system can be an ideal technology to use for traps that are hard to inspect manually due to their location such as in tunnels or confined spaces. If the traps are in an area that is inaccessible, the costs for inspection on an annual basis may be prohibitive.
In the summer of 2007, 3M applied for a custom rebate from Xcel Energy for their SteamEye installation and offered MnTAP their most recent trap testing data for review. This data resulted from the tests of 5,600 traps ranging from 10 to 285 psig conducted using sophisticated equipment. The facility reported that traps were tested annually; however, high failure rates were detected. DOE recommendations are to inspect such traps weekly to monthly versus annually. 3M needed to determine where the SteamEye system could be justified to bring the failure rate to 0%. From the data provided, MnTAP determined that expected energy savings for installing SteamEye will be dependent on the failure rate, trap pressure, and annual cost of steam loss for a specific trap. MnTAP was able to assist 3M with their successful rebate application and the facility has installed the SteamEye system.
Assessments shed light on leaking traps
During the past year, MnTAP has worked with Xcel Energy customers and conducted over 35 steam trap assessments at facilities in Minnesota. From this testing, MnTAP found that a number of facilities had steam traps that are in need of repair or replacement. Once MnTAP conducts a steam trap assessment, the facility receives a detailed report outlining traps that are problematic and options for repair or replacement. Often, this report also includes information about potential rebates from the facility’s utility provider. Recognizing a leak immediately and repairing or replacing problematic steam traps will result in energy and cost savings and may qualify for such rebates.
MnTAP worked with ISD 622 and conducted steam trap assessments for school buildings in the district. From those assessments, the district realized that a number of traps needed to be repaired or replaced. “We continue to work on the schools that were assessed...The report that was provided was thorough and has continued to be an energy savings tool for our team,” Laurie Hawkins said.
Saint Anthony Park United Methodist Church, another site MnTAP visited, has already recognized the cost savings associated with steam trap testing. “We ended up replacing 21 traps this winter, which was more than the 12 originally planned. We have applied for an Xcel Energy rebate to help with the additional cost,” Pastor Donna Martinson said. “However, we have had a $4000 month for heating in the past, but not this winter. I think that’s a sign of the improvement due to the repairs.” The church is also planning to purchase a steam trap tester to stay on top of their steam system.
At Minnesota State University - Moorhead, MnTAP conducted an inspection of steam traps in the residential buildings, steam tunnel and heating plant, which represents only 12% of the facility’s system. Tom Schmidt reports that during the follow-up from MnTAP’s inspection, the facility found that most traps had a plugged inlet strainer. Therefore, he installed valves on the strainers to allow them to blow down while at operating pressure.
Inspect traps to save money
MnTAP found that facilities are not conducting steam trap inspections as recommended by the DOE. When facilities do not follow DOE inspection recommendations, the trap failure rate and associated energy costs will increase. Therefore, facilities with steam traps should review the DOE testing frequency recommendations and implement a maintenance schedule to lower the likelihood of failure and save money and energy.
For more information about steam trap testing or SteamEye technology, call Nancy Kelly at 612.624.1300.
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