FEDERAL ENERGY MANAGEMENT PROGRAM

Steam Trap Function

Steam traps are automatic valves used in

every steam system to remove condensate, air, and other non-condensable gases

while preventing or minimizing the passing 

of steam. If condensate is allowed to collect, it

reduces the flow capacity of steam lines and the

thermal capacity of heat transfer equipment. In

addition, excess condensate can lead to “water

hammer,” with potentially destructive and 

dangerous results. Air that remains after system

startup reduces steam pressure and temperature

and may also reduce the thermal capacity of heat

transfer equipment.

Non-condensable gases, such as oxygen and

carbon dioxide, cause corrosion. Steam that

passes through the trap provides no heating service. This effectively reduces the heating capacity

of the steam system or increases the amount of

steam that must be generated to meet the heating

demand. Where condensate is not returned to

the boiler, water losses will be proportional to

the energy losses associated with leaking steam.

Feedwater treatment costs will be proportionately increased. In turn, an increase in

make-up water increases the blowdown

requirement and associated energy and

water losses. Even where condensate is

returned to the boiler, steam bypassing a

trap may not condense prior to arriving

at the deaerator, where it may be vented

along with the non-condensable gases.

Performance Assessment Methods

Steam trap performance assessment is 

basically concerned with answering the

following two questions:

1) Is the trap working correctly or not?

2) If not, has the trap failed in the open

or closed position?

Approximately 20% of the steam leaving a central boiler plant is lost via leaking traps in typical

space heating systems without proactive assessment programs. Losses can be significantly and

easily reduced by implementing a program using portable test equipment. Fixed test equipment, allowing continuous monitoring and 

evaluation, can reduce losses to less than 1%.

The potential impact in the Federal sector is

enormous; annual savings associated with

implementing an assessment program using 

portable equipment is estimated to be about 

$80 million, with an average payback period of

less than half a year.

This Federal Technology Alert, one in a series on

new technologies, describes the various techniques and technologies for evaluating steam

traps, with a focus on more advanced technologies utilizing ultrasonic sound or fluid 

conductivity measurement. A methodology for

estimating the costs and benefits of implementing a proactive steam trap maintenance program

is also presented along with the results of a sitespecific Federal application.

Steam Trap Performance Assessment

Advanced technologies for evaluating the performance of steam traps

Internet: http://www.eren.doe.gov/femp

Federal 

Technology

Alert

A publication series 

designed to speed the

adoption of energyefficient and renewable

technologies in the

Federal sector

Prepared by the 

New Technology 

Demonstration Program

The U.S. Department 

of Energy requests that no

alterations be made without

permission in any reproduction of this document.

DOE/EE-0193

Computerized steam trap management system.

Photo courtesy of TLV CORPORATION
Sight, sound, and temperature measurements have been used to assess the performance of steam traps since steam

traps were invented, but the measuring

technology has evolved over the years.

In particular, sound measurement has

progressed to include ultrasonic devices

that compare measured sounds with the

expected sounds of working and nonworking traps to render a judgment on

trap condition. Equipment using a fourth

method, based on the conductivity of the

fluid at a specific point in the pipeline,

has also been developed in recent years.

These advanced technologies are often

coupled with temperature-measuring

capability to increase diagnostic accuracy.

Where to Apply

Steam trap performance assessment

equipment varies significantly in initial

cost and moderately in operating cost

and assessment effectiveness. For 

smaller steam systems with relatively

few traps and/or for energy managers

with exceptionally small budgets, a

simple ultrasonic gun (without built-in

diagnostics) is probably the best investment. However, where many different

staff may be called upon to conduct

tests, the incremental investment in an

ultrasonic gun with built-in diagnostics

makes the most sense. The built-in diagnostic capability practically eliminates

the need for training, which is essential

to achieving good results without builtin diagnostics, but would be expensive

if a large group had to be trained.

Conductivity-based assessment equipment offers the best performance 

improvement and lowest operating

costs via continuous, remote monitoring, but installation of the sensing chambers and wiring make this the most

capital-intensive steam trap assessment

system. The extra investment is most

likely to be cost-effective in steam systems serving heating equipment with

relatively large loads and, hence, relatively large steam traps. Larger steam

traps, when failed open, result in larger,

more expensive leaks. Industrial process

heating applications would be most 

attractive for this type of assessment

system, but space-heating applications should not be excluded from 

consideration.

What to Avoid

The retrofit of sight glasses or test valves

allowing a visual assessment of steam

trap performance should be carefully

considered. While visual assessment is

judged by the majority of steam trap

experts to be the best assessment technique, the cost of retrofitting this type of

equipment is significantly greater than

any portable temperature or sonic test

equipment and comparable to conductivity-based test equipment. The latter

has the advantage of being wired for

continuous, remote monitoring, however, which should reduce operating

costs and improve steam system efficiency for a relatively modest incremental investment, compared with sight

glasses or test valves.

Bottom Line

The widespread cost-effectiveness of

proactive steam trap maintenance is

well documented in the literature. Thus,

implementing almost any type of steam

trap maintenance program will be beneficial; selecting the specific type of

assessment equipment is of secondary

importance.

FEDERAL ENERGY MANAGEMENT PROGRAM
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FEDERAL ENERGY MANAGEMENT PROGRAM

trap performance assessment equipment and programs are estimated to

be about $20 million. Based on investment costs of only $8 million, the average payback period is less than half a

year. The total present value of savings

over a 25-year period was estimated 

to be about $200 million. Department

of Defense (DoD) and Federal sector

impacts are probably about three and

four times as great, respectively, as the

Army impacts.

Steam trap performance assessment

has traditionally been based on three

basic methods: sight, sound, and 

temperature. This Federal Technology

Alert focuses on ultrasonic sound measurement equipment and equipment

utilizing a fourth method based on

conductivity. A sight glass specifically

designed for steam trap performance assessment

is also included.

The first two sections present background material that describes the basic types of steam traps

and performance assessment methods. The next

section describes the technologies included in

this Federal Technology Alert in more detail. Subsequent sections describe how to use the technologies and the experiences of Federal sector users.

Details regarding development of the Army 

impacts noted above and the results of a specific

program initiated at three Veterans Administration hospitals are also documented. Finally, 

Appendix A provides detailed information on

manufacturers and their products, and Appendix B gives Federal life-cycle costing procedures.

Abstract

Various types of performance assessment equipment can be used as part of a proactive steam trap

maintenance program to significantly reduce 

energy losses in steam distribution systems. 

Approximately 20% of the steam leaving a central boiler plant is lost via leaking traps in typical

space heating systems without proactive maintenance programs.1 Relatively simple equipment

and programs can easily cut losses in half. Intermediate equipment and programs can cut losses

in half again. The best equipment and programs

can reduce losses to less than 1%.2

The potential impact in the Federal sector is enormous. In the Army alone, the annual savings 

associated with implementing intermediate steam

Steam Trap Performance Assessment

Advanced technologies for evaluating the performance of steam traps

Federal 

Technology

Alert

1 Estimated based on data presented in Pychewicz (1985), Vallery (1981), and Johnson and Lawlor (1985).

2 A “simple” program would use rudimentary portable test equipment once a year. An “intermediate” program

would use more sophisticated portable test equipment twice year. The “best” program would use permanently installed test equipment allowing continuous monitoring and evaluation.

Three-way valves on either side a steam trap comprise a

trap test station. They make it easy to test traps and to

check on back pressure in the system.

Photo courtesy of Armstrong International, Inc.

1
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FEDERAL ENERGY MANAGEMENT PROGRAM

Contents

Abstract............................................................................................................................ 1

About the Technology .................................................................................................. 5

Steam Trap Overview

Performance Assessment Methods

Application Domain

Energy-Saving Mechanism

Other Benefits

Installation

Federal Sector Potential ................................................................................................ 11

Estimated Savings and Market Potential

Laboratory Perspective

Application...................................................................................................................... 12

Application Screening

Where to Apply

What to Avoid

Equipment Integration

Maintenance Impact

Equipment Warranties

Costs

Technology Performance .............................................................................................. 14

Case Study ...................................................................................................................... 14

Facility Description

Existing Technology Description

New Technology Equipment Selection

Savings Potential

Life-Cycle Costs

The Technology in Perspective .................................................................................... 16

The Technology’s Development

Technology Outlook

Manufacturers ................................................................................................................ 17

Who is Using the Technology ...................................................................................... 17

For Further Information................................................................................................ 18

Appendix A Steam Trap Monitoring Equipment Information............................ 21

Appendix B Federal Life-Cycle Costing Procedures 

and the BLCC Software ...................................................................... 32
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FEDERAL ENERGY MANAGEMENT PROGRAM

About the Technology

The focus of this Federal Technology Alert

(FTA) is on advanced technologies for

evaluating the performance or working condition of steam traps. However,

prior to discussing techniques and

equipment for evaluating steam traps, 

a brief overview of steam trap functions,

designs, and operating characteristics is

provided. At least a rudimentary understanding of steam trap principles is necessary to understand how the various

evaluation approaches work and why

some are more likely to produce a better

evaluation than others. Those not familiar with steam traps are also referred to

several references listed at the end of

this FTA that provide a more detailed

discussion.

Steam Trap Overview

Steam traps are automatic valves used

in every steam system to remove condensate, air, and other non-condensable

gases while preventing or minimizing

the passing of steam. If condensate is 

allowed to collect, it reduces the flow

capacity of steam lines and the thermal

capacity of heat transfer equipment. In

addition, excess condensate can lead 

to “water hammer,” with potentially

destructive and dangerous results. 

Air that remains after system startup 

reduces steam pressure and temperature and may also reduce the thermal

capacity of heat transfer equipment.

Non-condensable gases, such as oxygen and carbon dioxide, cause corrosion.

Finally, steam that passes through the

trap provides no heating service. This

effectively reduces the heating capacity

of the steam system or increases the

amount of steam that must be generated to meet the heating demand.

The objective of the steam trap is not an

easy task and condensate pressures and

flow rates vary significantly at various

points in a steam distribution system. As

a result, many different types of steam

traps have been developed. Steam traps

are commonly classified by the physical

process causing them to open and close.

The three major categories of steam

traps are 1) mechanical, 2) thermostatic,

and 3) thermodynamic. In addition,

some steam traps combine characteristics of more than one of these basic 

categories.

The operation of a mechanical steam

trap is driven by the difference in density between condensate and steam.

The denser condensate rests on the 

bottom of any vessel containing the two

fluids. As additional condensate is generated, its level in the vessel will rise.

This action is transmitted to a valve via

either a “free float” or a float and connecting levers in a mechanical steam

trap. One common type of mechanical

steam trap is the inverted bucket trap,

shown in Figure 1. Steam entering the

submerged bucket causes it to rise 

upward and seal the valve against the

valve seat. As the steam condenses 

inside the bucket or if condensate is

predominately entering the bucket, the

weight of the bucket will cause it to sink

and pull the valve away from the valve

seat. Any air or other non-condensable

gases entering the bucket will cause it

to float and the valve to close. Thus, the

top of the bucket has a small hole to 

allow non-condensable gases to escape.

The hole must be relatively small to

avoid excessive steam loss.

As the name implies, the operation of a

thermostatic steam trap is driven by 

the difference in temperature between

steam and sub-cooled condensate. Valve

actuation is achieved via expansion and

contraction of a bimetallic element or a

liquid-filled bellows. Bimetallic and bellows thermostatic traps are shown in

Figures 2 and 3. Although both types of

thermostatic traps close when exposure

to steam expands the bimetallic element

or bellows, there are important differences in design and operating characteristics. Upstream pressure works to open

the valve in a bimetallic trap, while 

expansion of the bimetallic element

works in the opposite direction. Note

that changes in the downstream pressure will affect the temperature at which

the valve opens or closes. In addition,

the nonlinear relationship between

steam pressure and temperature requires

careful design of the bimetallic element

for proper response at different operating pressures. Upstream and downstream pressures have the opposite 

effect in a bellows trap; an increase in

upstream pressure tends to close the

valve and vice versa. While higher temperatures still work to close the valve,

the relationship between temperature

and bellows expansion can be made to

vary significantly by changing the fluid

inside the bellows. Using water within

Figure 1. Inverted bucket steam trap.

Illustration courtesy of Yarway Corporation
6

FEDERAL ENERGY MANAGEMENT PROGRAM

Figure 3. Bellows steam trap.

Figure 2. Bimetallic steam trap

the bellows results in nearly identical

expansion as steam temperature and

pressure increase, because pressure 

inside and outside the bellows is nearly

balanced.

In contrast to the inverted bucket trap,

both types of thermostatic traps allow

rapid purging of air at startup. The 

inverted bucket trap relies on fluid 

density differences to actuate its valve.

Therefore, it cannot distinguish between

air and steam and must purge air (and

some steam) through a small hole. A

thermostatic trap, on the other hand, 

relies on temperature differences to 

actuate its valve. Until warmed by

steam, its valve will remain wide open,

allowing the air to easily leave. After the

trap warms up, its valve will close, and

no continuous loss of steam through a

purge hole occurs. Recognition of this

deficiency with inverted bucket traps or

other simple mechanical traps led to the

and decrease in pressure as the condensate flows through the trap, following

the 1st law of thermodynamics and the

Bernoulli equation. As the condensate

entering the trap increases in temperature it will eventually flash to steam 

because of the localized pressure drop

just described. This increases the velocity and decreases the pressure even 

further, causing the disc to snap closed

against the seating surface. The moderate

pressure of the flash steam on top of the

disc acts on the entire disc surface, creating a greater force than the higher pressure steam and condensate at the inlet,

which acts on a much smaller portion

of the opposite side of the disc. Eventually, the disc chamber will cool, the flash

steam will condense, and inlet condensate will again have adequate pressure

to lift the disc and repeat the cycle.

Performance Assessment

Methods

Steam trap performance assessment is

basically concerned with answering the

following two questions:

1) Is the trap working correctly or not?

2) If not, has the trap failed in the open 

or closed position?

Traps that fail open result in a loss of

steam and its energy. Where condensate

is not returned, the water is lost as well.

The result is significant economic loss,

directly via increased boiler plant costs,

and potentially indirectly, via decreased

steam heating capacity. Traps that fail

closed do not result in energy or water

losses, but can result in significantly 

reduced heating capacity and/or damage to steam heating equipment.

There are three basic methods for evaluating a steam trap that are commonly

discussed in the literature: sight, sound,

and temperature. The three are discussed

below in the general order of reliability.

At least two of the three methods should

be used to increase the chances of correctly identifying the condition of a

steam trap. A less commonly discussed

development of float and thermostatic

traps. The condensate release valve is

driven by the level of condensate inside

the trap, while an air release valve is

driven by the temperature of the trap. 

A float and thermostatic trap is shown

in Figure 4.

Thermodynamic trap valves are driven

by differences in the pressure applied

by steam and condensate, with the presence of steam or condensate within the

trap being affected by the design of the

trap and its impact on local flow velocity

and pressure. Disc, piston, and lever 

designs are three types of thermodynamic traps with similar operating principles; a disc trap is shown in Figure 5.

When subcooled condensate enters the

trap, the increase in pressure lifts the

disc off its valve seat and allows the condensate to flow into the chamber and

out of the trap. The narrow inlet port

results in a localized increase in velocity Illustration courtesy of Yarway Corporation Illustration courtesy of Yarway Corporation
7

FEDERAL ENERGY MANAGEMENT PROGRAM

method is based on fluid conductivity.

Although this method should be at least

as reliable as sonic-based methods, it is

discussed less frequently in the literature, and no general consensus on its

relative reliability was evident.

Sight Method

The sight method is usually based on a

visual observation of the fluid downstream of the trap. This is possible if

there is no condensate recovery system

or if test valves have been installed to 

allow a momentary discharge of the

downstream fluid from the condensate

recovery system. In either case, the steam

trap evaluator must be able to distinguish between “flash” steam, which is

characteristic of a properly working

trap, and “live” steam, which is characteristic of a trap that has failed open

and is leaking or blowing a significant

amount of steam. Flash steam is created

when a portion of the condensate flashes

to vapor upon expansion to atmospheric

pressure. Flash steam is characterized

by a relatively lazy, billowy plume. Live

steam, on the other hand, will form a

much sharper, higher velocity plume

that may not be immediately visible as

it exits the test valve or steam trap. The

difference between live steam and flash

steam is illustrated in Figure 6.

Sight glasses can also be used for a visual

observation, but have some drawbacks

that must be overcome or avoided. First,

steam and condensate are both expected

to exist upstream and downstream of

the trap (live steam on the upstream side

and flash steam on the downstream

side). Second, the view through a sight

glass tends to deteriorate over time 

because of internal or external fouling.

Third, both steam and condensate will

appear as clear fluids within the pipe. In

response to the first and third concerns,

sight glasses have been developed with

internal features that allow the proportion of steam and condensate to be identified. Incorporation of a sight glass into

a pipe is shown in Figure 7a. Normal

and abnormal operating conditions

viewed through a sight glass are illustrated in Figures 7b, 7c, and 7d for a

sight glass installed on the upstream

side of the trap. In Figure 7b normal 

operation results in a condensate level

that is just above the internal flow baffle.

Moderate to high rates of steam flow

past the baffle (indicating a leaking or

blowing steam trap) will sweep out most

of the condensate, as shown in Figure 7c.

A completely flooded baffle, shown in

Figure 7d, could be caused by excess

condensate formed during startup, a

steam trap that is undersized for normal

condensate loads, blockage in the condensate return system, or a steam trap

that has failed closed or nearly so. Additional investigation is required to determine which of the alternative causes is

the likely source of the problem.

Sound Method

Mechanisms within steam traps and the

flow of steam and condensate through

steam traps generate sonic (audible to

the human ear) and supersonic sounds.

Proper listening equipment, coupled

with the knowledge of normal and 

abnormal sounds, can yield reliable 

assessments of steam trap working 

condition. Listening devices range 

from a screwdriver or simple mechanic’s

stethoscope that allow listening to sonic

sounds to more sophisticated electronic

devices that allow “listening” to sonic or

Figure 4. Float and thermostatic steam trap

Figure 5. Disc steam trap.

Illustration courtesy of Yarway Corporation Illustration courtesy of Yarway Corporation
8

FEDERAL ENERGY MANAGEMENT PROGRAM

Figure 6. Live steam versus flash steam.

Figure 7. Sight glass evaluation.

sonic and ultrasonic sounds at selected

frequencies. The most sophisticated 

devices compare measured sounds 

with the expected sounds of working

and non-working traps to render a judgment on trap condition. A typical ultrasonic test kit is shown in Figure 8.

Temperature Method

Measuring the temperature of the steam

trap is generally regarded as the least

reliable of the three basic evaluation

techniques. Saturated steam and condensate exist at the same temperature, of

course, so it’s not possible to distinguish

between the two based on temperature.

Still, temperature measurement provides

important information for evaluation

purposes. A cold trap (i.e., one that is

significantly cooler than the expected

saturated steam temperature) indicates

that the trap is flooded with condensate, assuming the trap is in service. As

described above for the visual test via a

sight glass, a flooded trap could mean

several things, but barring measurement

during startup, when flooding can be

expected, generally indicates a problem

that needs to be addressed. Downstream

temperature measurement may also

yield useful clues in certain circumstances. For example, the temperature

downstream of a trap should drop off

Figure 8. Ultrasonic test kit.

Photo courtesy of Yarway Corporation Illustration courtesy of GESTRA, Inc.

Photo courtesy of GESTRA, Inc.

7a Cutaway View
9

FEDERAL ENERGY MANAGEMENT PROGRAM

relatively quickly if the trap is working

properly (mostly condensate immediately past the trap). On the other hand,

the temperature downstream of the 

trap will be nearly constant if significant

steam is getting past the trap. Care must

be taken not to use this technique where

other traps could affect downstream

conditions, however.

Temperature measurement methods,

like sound measurement, vary tremendously in the degree of sophistication.

At the low-end, spitting on the trap and

watching the sizzle provides a general

indication of temperature. For the more

genteel, a squirt bottle filled with water

will serve the same purpose. Alternatively, a glove-covered hand can provide

a similar level of accuracy. More sophisticated are various types of temperaturesensitive crayons or tapes designed to

change color in different temperature

ranges. Thermometers, thermocouples,

and other devices requiring contact with

the trap offer better precision. Finally,

non-contact (i.e., infrared) temperature

measuring devices provide the precision

of thermometers and thermocouples

without requiring physical contact.

Non-contact temperature measurement makes it easier to evaluate traps

that are relatively difficult or dangerous

to access closely. An infrared temperature

measuring “gun” is shown in Figure 9.

Conductivity Method

Conductivity-based diagnostics are

based on the difference in conductivity

between steam and condensate. A conductivity probe is integrated with the

steam trap or just upstream of the steam

trap in a sensing chamber. Under normal

operation, the tip of the conductivity

probe is immersed in condensate. If the

steam trap leaks excessively or is blowing, steam flow will sweep away the

condensate from the test probe tip and

conductivity corresponding to steam

will be measured. Thus, the sensing

chamber and the existence of steam and

condensate under normal and leaking

or blowing conditions are similar to that

heating systems and steam traps are

used. Steam can be used for space and

process heating. Space-heating with

steam is more common in the Federal

sector than other sectors, which can be

attributed to a tendency for Federal

buildings to be larger, grouped closely

together in campus-like arrangements,

or constructed in an era when central

boiler systems were the preferred heating system. The Department of Defense

has about 5,000 miles of steam distribution systems, not including piping

within buildings. Larger forts or bases

can easily have more than 10,000 steam

traps. Proactive steam trap maintenance

programs are believed to be the exception, rather than the rule, in the Federal

sector due to a shortage of maintenance

staff. On the other hand, essentially all

studies of steam trap maintenance programs reported in the literature suggest

that energy savings far exceed implementation costs. Thus, the potential 

incremental application of steam trap

performance evaluation equipment is

significant when measured by either 

the size or fraction of the market.

Energy-Saving Mechanism

Monitoring and evaluation equipment

does not save any energy directly, but

identifies traps that have failed and

whether failure has occurred in an open

or closed position. Traps failing in an

open position allow steam to pass continuously, as long as the system is energized. The rate of energy loss can be 

estimated based on the size of the orifice

and system steam pressure using the 

relationship illustrated in Figure 10.

This figure is derived from Grashof’s

equation for steam discharge through

an orifice (Avallone and Baumeister

1986) and assumes the trap is energized

(leaks) the entire year, all steam leak 

energy is lost, and that makeup water is

available at an average temperature of

60°F. Boiler losses are not included in

Figure 10, so must be accounted for

separately. Thus, adjustments from the

raw estimate read from this figure must

Figure 9. Infrared temperature gun.

described above and shown in Figure 7

for the sight glass.

Conductivity measurement must be 

accompanied by temperature measurement to ensure a correct diagnosis. For

example, an indication of steam and a

trap that has failed open could occur if a

trap has not been used recently and has

filled with air. The conductivity of air is

similar to steam, but a trap filled with air

would be close to ambient temperature,

in contrast to a trap filled with steam.

Similarly, the presence of condensate

could mean the trap is working properly, but could also mean that 1) the trap

has flooded, either because the trap has

failed closed or something else is blocking the line, 2) the trap is undersized, or

3) the heat transfer equipment served

by the trap is warming up to its normal

operating temperature and generating

an unusually large amount of condensate for a short period. These alternative

conditions would be indicated by low

temperature in conjunction with the

presence of condensate.

Application Domain

Steam trap monitoring equipment

should be employed wherever steam

Photo courtesy of Raytek Corporation
10

FEDERAL ENERGY MANAGEMENT PROGRAM

be made to account for less than full

time steam supply and for boiler losses.

The principal uncertainty in using the

Figure 10 energy loss rates is estimating

the equivalent hole diameter for a trap

suspected of leaking or blowing steam.

Vendor advice can be solicited to identify the orifice size for a trap when fully

open. However, not all traps fail in this

mode. Rather than being stuck open, the

trap valve may no longer seal properly,

resulting in a smaller hole. Intermediate

failure modes are also possible. Whether

a trap has lost its seal or is stuck fully

open, the flow of condensate through

the orifice reduces the area available for

steam flow. Fischer (1995) estimates that

condensate flow reduces steam flow 

by 1/3 to 1/2 of that expected without

condensate. The variation depends on

the sizing of the trap relative to expected

condensate load. In addition, steam trap

internals create flow restrictions that 

reduce losses relative to unimpeded

flow through an orifice.

The maximum steam loss rate occurs

when a trap fails with its valve stuck in a

fully opened position. While this failure

mode is relatively common, the actual

orifice size could be any fraction of the

fully opened position. Therefore, judgment must be applied to estimate the

orifice size associated with a specific

malfunctioning trap. Lacking better

data, assuming a trap has failed with an

orifice size equivalent to one-half of its

fully-opened condition is probably prudent. Additional advice on estimating

losses from individual traps can be

found in Pychewicz (1985), David

(1981), and Tuma and Kramer (1988).

The use of Figure 10 is illustrated via

the following example. Inspection and

observation of a trap led to the judgment that it had failed in the fully open

position and was blowing steam. Manufacturer data indicated that the actual

orifice diameter was 3/8 inch. The trap

operated at 60 psia and was energized

for 50% of the year. Boiler efficiency

was estimated to be 75%. Calculation

of annual energy loss for this example

is illustrated in the sidebar on page 11.

Other Benefits

Where condensate is not returned to 

the boiler, water losses will be proportional to the energy losses noted above.

Feedwater treatment costs will also be

proportionately increased. In turn, an

increase in make-up water increases the

Figure 10. Energy loss from leaking steam traps.

Steam Leaks
11

FEDERAL ENERGY MANAGEMENT PROGRAM

blowdown requirement and associated

energy and water losses. Even where

condensate is returned to the boiler,

steam bypassing a trap may not condense prior to arriving at the deaerator,

where it may be vented along with the

non-condensable gases. Steam losses also

represent a loss in steam-heating capacity, which could result in an inability to

maintain the indoor design temperature

on winter days or reduce production

capacity in process heating applications.

Traps that fail closed do not result in

energy or water losses, but can also 

result in significant capacity reduction

(as the condensate takes up pipe crosssectional area that otherwise would be

available for steam flow). Of generally

more critical concern is the physical

damage that can result from the irregular movement of condensate in a twophase system, a problem commonly 

referred to as “water hammer.”

Installation

Installation requirements are essentially

nil for portable test equipment, which

includes ultrasonic systems with or

without built-in diagnostic capability.

Some training will be required for the

ultrasonic systems without built-in 

diagnostics, however, for the user to

correctly interpret the signals received.

The conductivity-based systems generally require a test chamber plumbed

into the pipeline just upstream from 

the steam trap, although some steam

traps have an integrated test chamber.

Continuous monitoring requires the 

installation of power and control wiring

to connect individual test probes to a

central monitoring terminal. Otherwise,

a portable monitoring device can be 

periodically connected to each test probe.

Sight glasses must also be plumbed into

the pipeline just upstream from the

steam trap.

Federal Sector Potential

Steam heating systems are relatively

common in the Federal sector. Total

boiler capacity, boiler energy consumption, steam piping length, and the number of traps in the Federal sector are not

directly available from databases, but

can be estimated from related data and

rules-of-thumb.

Estimated Savings 

and Market Potential

Implementation of a proactive steam

trap program (i.e., a program based on

regular maintenance checks rather than

only replacing steam traps when failure

creates an intolerable operating condition) can save significant energy. The 

results of several steam trap programs

described in the literature suggest that

failed steam traps leak approximately

20% of the steam leaving the boiler in

predominately space-heating systems

lacking a proactive maintenance program. The same sources suggest that

the loss rate would be reduced to about

6% by the average proactive maintenance program. If the average loss rate

for a proactive program is 6%, then a

minimal program (using rudimentary

test equipment) might reduce losses to

about 8% and an intermediate program

(using good portable equipment and

more frequent testing) should yield better results, reducing losses to perhaps 4%.

With an advanced program (using hardplumbed and wired equipment allowing continuous monitoring), the loss

rate should approach 0%.

In general, each increment of improvement in the steam trap loss rate requires

an increased investment in labor and

equipment. Equipment costs are negligible for either the minimal or intermediate programs, but would increase 

significantly for the advanced program,

which requires the installation of new

hardware, including retrofit of the existing steam piping. The significant investment associated with the advanced

program is probably not justified in

most Federal applications, which are

predominately for building space heating. Compared to typical industrial process heating applications, end-use heat

exchanger condensate loads are small

for typical space heating applications.

Thus, smaller steam traps are used, and

the potential loss from a single trap

probably does not warrant the expense

of an advanced program. This generalization should be revisited in any sitespecific analysis, however.

The estimated savings and market 

potential were estimated by evaluating

the cost-effectiveness of implementing

either a minimal or intermediate proactive steam trap maintenance program.

80% of Federal sites were assumed not

to have a proactive maintenance program. 15% were assumed to have a

minimal program and 5% an intermediate program. No Federal sites were presumed to have an advanced program.

The costs of implementing a minimal 

or intermediate program, or upgrading

from a minimal program to an intermediate program, were estimated from

rules-of-thumb provided in publications

describing proactive steam trap maintenance programs. Program requirements

Estimating steam loss using Figure 10

Assume: 3/8-inch-diameter orifice steam trap, 50% blocked, 60 psia saturated steam system, steam system energized 4,380 h/yr (50% of year), boiler efficiency 75%.

• Using Figure 10 for 3/8 inch orifice and 60 psia steam, steam loss = 2,500 million Btu/yr

• Assuming trap is 50% blocked, annual steam loss estimate = 1,250 million Btu/yr

• Assuming steam system is energized 50% of the year, energy loss = 625 million Btu/yr

• Annual fuel loss including boiler losses = [(625 million Btu/yr)/(75% efficiency)] = 833

million Btu/yr
12

FEDERAL ENERGY MANAGEMENT PROGRAM

include an initial identification of all

steam trap locations, purchase of test

equipment, training, trap testing, 

trap replacement, and engineering

management.

Estimated costs for the two programs,

as a function of the total trap population,

are shown in Table 1. The minimal program is presumed to use whatever testing equipment is already available, so

no expenditure for equipment or equipment-use training is required. Traps are

presumed to be tested once a year for

the minimal program and twice a year

for the intermediate program, which 

explains the difference in trap testing

and engineering management costs for

the two programs. The intermediate

program is presumed to do a better job

of assessing trap condition; a higher

percentage of traps that have failed are

identified as having failed and a lower

percentage of traps that are working correctly are misidentified as having failed.

Thus, a lower percentage of steam traps

are still leaking after completing a test

and repair cycle with the intermediate

program. In addition, subsequent failures accumulate for only six months for

the intermediate program compared 

to a year for the minimal program. The

combined effect is presumed to cut 

energy losses for the intermediate program in half compared to the minimal

program.

Consider a hypothetical facility with

100,000 lb/hr of steam generating 

capacity, 500 traps, annual steam production of 219,000,000 lb, and a marginal

cost of steam production of $5/thousand

pounds. Implementation of the minimal

program would save 26,280,000 lb of

steam valued at $134,000 every year for

an initial cost of $27,500 plus annually

recurring costs of $16,000. Implementation of the intermediate program would

save 35,040,000 lb of steam valued at

$175,200 every year for an initial cost of

$31,500 plus annually recurring costs 

of $19,500. The payback periods for the

minimal and intermediate programs 

are 0.23 and 0.20 years, respectively.

The calculations in the previous paragraph provide the economic justification to proceed with trap identification

and testing, resulting in a more accurate

assessment of trap conditions and steam

losses, hence trap replacement costs

and energy savings. The life-cycle cost

calculations should be repeated once

this additional information is available 

to determine if trap replacement is still

economically justified. Note that money

already spent for trap identification and

initial testing are “sunk” and should not

be included in the subsequent calculation.

The potential economic and environmental impacts of implementing costeffective steam trap maintenance

programs in the Army are shown in 

Table 2. The results are quite impressive.

Annual energy savings could be about

5 trillion btu, with the present value of

annual savings (annual energy savings

less annual program costs) and the net

present value (after paying for initial

program investment costs) both in excess

of $200 million. The data required for

accurate estimates were not available,

but DoD and Federal sector impacts are

probably about three and four times as

great, respectively, as the Army impacts.

Laboratory Perspective

The cost-effectiveness of proactive steam

trap maintenance is well documented

in the literature. In general, it’s far more

important to ensure that steam traps 

are evaluated on a regular basis than to

worry about which specific type of testing equipment is used. A more careful

analysis of the costs and benefits is 

justified, however, if some of the more

expensive options requiring hardware

installation are considered. Still, the 

efficiency improvement offered by 

these more sophisticated systems may

be justified for systems with larger steam

traps that lose much more steam upon

failure. The pervasive existence of steam

heating systems coupled with relatively

few proactive steam trap maintenance

programs in the Federal sector presents

a substantial opportunity for energy

savings and related benefits.

Application

This section describes in more detail 

the technical considerations regarding

implementation of a proactive steam

trap maintenance program and selection of steam trap testing equipment.

The first few paragraphs describe the

Table 1. Steam trap proactive maintenance program cost estimates.3

Cost Element Minimal Program Intermediate Program

Trap Identification $15/trap once $15/trap once

Equipment and Training $0 total once $4000 total once

Trap Testing $5/trap per year $10/trap per year

Trap Replacement $40/trap first year $40/trap first year

$15/trap thereafter $15/trap thereafter

Engineering Management $5000 + $2/trap/year $5000 + $4/trap/year

Total Initial Cost $55/trap $4000 + $55/trap

Total Annual Cost $5000 + $22/trap $5000 + $29/trap

3 Estimates were developed from information presented in Hooper and Gillette (1997), Garcia

Gaggioloi (1986), Miller (1985), Johnson and Lawlor (1985), Lane (1983), Vallery (1981), and

FEMP (1996).
13

FEDERAL ENERGY MANAGEMENT PROGRAM

conditions and characteristics where a

maintenance program and specific types

of equipment should be applied and 

situations that should probably be

avoided. Subsequent sections focus 

on equipment integration impacts, 

including installation requirements,

equipment and installation costs, and

maintenance requirements.

Application Screening

Some type of steam trap performance

assessment program should be implemented anywhere steam heating systems and steam traps are used. Even for

smaller systems with only a handful of

traps, some type of steam trap program

will be cost-effective. The use of temperature and sound measurement equipment

currently available in your maintenance

shop, even if limited to a gloved hand

and a screwdriver, is better than having

no regular assessment program at all.

The most important decision is to implement a steam trap performance assessment program. Selection of the specific

performance assessment equipment is 

a secondary consideration.

Where to Apply

The steam trap performance assessment

equipment described in this FTA varies

significantly in initial cost and moderately in operating cost and assessment

effectiveness. For smaller steam systems with relatively few traps and/or

for energy managers with exceptionally

small budgets, a simple ultrasonic gun

(without built-in diagnostics) is probably

the best investment. However, where

many different staff may be called upon

to conduct tests, the incremental investment in an ultrasonic gun with built-in

diagnostics makes the most sense. The

built-in diagnostic capability practically

eliminates the need for training, which

is essential to achieving good results

without built-in diagnostics, but would

be expensive if a large group had to be

trained. Conductivity-based assessment

equipment offers the best performance

improvement and lowest operating

costs via continuous, remote monitoring,

but installation of the sensing chambers

and wiring make this the most capitalintensive steam trap assessment system.

The extra investment is most likely to

be cost-effective in steam systems serving

heating equipment with relatively large

loads and, hence, relatively large steam

traps. Larger steam traps, when failed

open, result in larger, more expensive

leaks. Industrial process heating applications would be most attractive for

this type of assessment system, but

space-heating applications should not

be excluded from consideration.

What to Avoid

The retrofit of sight glasses or test valves

allowing a visual assessment of steam

trap performance should be carefully

considered. While visual assessment is

judged by the majority of steam trap 

experts to be the best assessment technique, the cost of retrofitting this type

of equipment is significantly greater

than any portable temperature or sonic

test equipment and comparable to 

conductivity-based test equipment. 

The latter has the advantage of being

wired for continuous, remote monitoring, however, which should reduce 

operating costs and improve steam system efficiency for a relatively modest

incremental investment, compared to

sight glasses or test valves.

Equipment Integration

Portable steam trap test equipment,

which includes all of the ultrasonic 

devices described in this FTA as well 

as most temperature-measuring equipment, requires no integration with the

steam distribution system. On the other

hand, conductivity-based and visualbased test equipment must be plumbed

into the distribution system. Some steam

traps have built-in conductivity sensor

chambers, but most utilize a separate

sensor chamber. Either approach requires

isolation of the steam trap and surrounding piping and insertion of a new device

(either a new steam trap with a sensing

chamber or a separate sensing chamber).

Sight glasses and test valves require a

similar retrofit. Conductivity chambers,

sight glasses, and test valves are generally available in models allowing

threaded, flanged, or welded connections to suit pipeline-specific requirements, but all require at least a moderate

amount of pipefitting labor to install.

Maintenance Impact

All steam trap performance assessment

equipment will require incremental labor

to collect and evaluate test data. Much

of this incremental labor is associated with

walking from one trap to another with

portable test equipment. This requirement can be eliminated with hard-wired,

Table 2. Potential Army impacts of proactive steam trap maintenance programs

Criteria Result

Net Present Value ($) 203,991,245

Installed Cost ($) 7,850,779

Present Value of Savings ($) 211,841,024

Energy Savings (million Btu/year) 5,197,636

SO2 Emissions Reduction (lb/year) 3,624,870

NOx Emissions Reduction (lb/year) 1,215,219

Particulate Emissions Reduction (lb/year) 68,721

CO Emissions Reduction (lb/year) 354,341

CO2 Emissions Reduction (tons/year) 368,695

Hydrocarbon Emissions Reduction (lb/year) 8,163
14

FEDERAL ENERGY MANAGEMENT PROGRAM

remotely accessed, conductivity-based

systems, however, with incremental labor

limited to periodic review and evaluation of the centrally collected data. Steam

trap replacement costs will increase, of

course, compared to not having a proactive steam trap maintenance program.

Otherwise, maintenance of the performance assessment equipment itself is

generally expected to be negligible. A

notable exception would be sight glasses,

which may require periodic removal

and cleaning to maintain clarity.

Equipment Warranties

A one-year warranty is standard for

most steam trap performance equipment and manufacturers covered in this

FTA. An exception to this generalization is the Ultraprobe‘ ultrasonic system manufactured by UE Systems, Inc.,

which is warranted for five years.

Costs

The costs of steam trap performanceassessment equipment vary significantly, depending on the type, its 

features, and its size (for sight glasses

and conductivity-based equipment 

that must be plumbed into the existing

pipeline). Fixed frequency ultrasonic

meters can be purchased for $600 or less

up to about $2,000. Tunable ultrasonic

test systems can usually be purchased

for $3,000 to $5,000. The purchase cost

of conductivity-sensing chambers and

sight glasses varies from less than $100

to more than $1,000 per trap, depending

on pipe diameter, pipe material, and the

type of connection (welded, flanged, or

threaded). Installation costs for conductivity test chambers and sight glasses are

also significant and variable, although

not generally as expensive or variable.

Depending on pipe size and connection

type, an additional $50–200 per trap can

be expected.

Rough estimates of other costs associated with a proactive steam trap maintenance program are shown in Table 1.

Technology Performance

Ultrasonic testing equipment, applicable to a wide-range of technologies

besides steam traps, has been used 

extensively in the Federal and private

sectors. Conductivity-based test equipment and sight glasses, both more peculiar to steam trap assessment, have been

used less frequently, but have still seen

significant use. All of the steam trap

performance assessment equipment 

included in this FTA could be described

as mature. In all cases, hundreds or

thousands of units or systems have been

sold. In general, a substantial fraction of

sales have been to the Federal sector, but

specific sales data for Federal and nonFederal sectors and customer references

were not always available. The specific

experiences of available references are

documented in this section. Contact 

information is provided in Appendix A.

Ted Tomaliwski of the National Institute

of Standards and Technology (NIST) in

Gaithersburg, Maryland, uses the 

CTRL Ultraphonic‘ ultrasonic tester.

Ted works at the central steam, chilled

water, and compressed air plant at the

NIST facility. Steam produced at the

central plant is primarily used for space

heating. Ted uses the Ultraphonic to

check for air leaks and malfunctioning

steam traps. Ted told us the Ultraphonic

“works well and is easy to use.” Ted

also uses a contact temperature probe 

to evaluate steam trap performance.

Charles McMullin has responsibility for

exterior steam lines at Whiteman Air

Force Base in Knobnoster, Missouri.

Charles has used TLV’s TrapMan‘ (an

integrated ultrasonic and temperature

measurement system with built-in diagnostics) for about 4 years, and considers

it an improvement over temperature

measurement devices that were previously used to evaluate steam traps.

Charles notes that performance data are

recorded by the system, so it takes very

little time to conduct the tests. Overall,

Charles says that he is “well satisfied”

with the TrapMan system.

CIS Services operates the Electric Power

Research Institute’s Monitoring and 

Diagnostics Center. CIS provides instruction on the inspection of transformers,

valves, and steam traps. They use Triple

5 Industries’ ultrasonic leak detector for

all of these applications. George Spencer

of CIS says that Triple 5 Industries’ ultrasonic leak detector is “the best system

you can buy.” In particular, George likes

the battery-powered portability of the

system, and claims the system is substantially faster than using temperature

systems for assessing steam traps.

Peter Palamidis is the Preventive Maintenance Coordinator at Brookhaven 

National Laboratory in Upton, New York.

Peter uses UE Systems’ UltraprobeTM

2000 to survey approximately 2,500

steam traps at his facility. Peter says the

Ultraprobe is a “good system,” and he

was especially enthusiastic about the

support that UE Systems provides its

customers.

Case Study

Steam trap management programs

were recently initiated at three Veterans

Administration (VA) medical centers in

the Northeast with the help of FEMP’s

SAVEnergy Program. The three VA

hospitals were located in Providence,

Rhode Island, and Brockton and West

Roxbury, Massachusetts. Steam trap 

inspection and evaluation was included

as part of broader audit of the steam

generation, distribution, and end-use

equipment at these three facilities. Steam

traps were identified and evaluated to

determine their performance and the

value of steam losses from malfunctioning traps. Malfunctioning traps were

designated for either repair or replacement. In addition, VA maintenance

crews received trap-testing training as

part of the continuing steam trap management program.
15

FEDERAL ENERGY MANAGEMENT PROGRAM

Facility Description

The key facility-level characteristics for

a steam trap management program are

the steam system pressure or pressures,

the hours per year that the steam system

is energized, and the marginal cost of

producing steam that is lost in faulty

traps. The steam pressure affects the rate

of steam loss through a leaking trap as

shown in Figure 10. Losses occur continuously at a constant rate (independent of end-use demand) whenever the

steam system in energized, so care must

be taken to estimate this factor correctly.

Individual pieces of steam-heated equipment or sections of a system may be 

energized for different portions of the

year. For example, space-heating lines

may be shut off during the summer

while domestic water heating is required

year round. In addition, the use of automated control valves (or not) will significantly affect the fraction of time 

that a steam trap is energized. The 

marginal cost of steam will equal fuel

cost divided by boiler efficiency at a

minimum. Makeup water treatment

costs should also be included for that

fraction of the leaking steam that fails 

to return to the boiler feed water tank.

Multiple steam pressures were found 

at each of the three medical centers. The

specific pressures were 110, 80, 40, and

15 psig at Providence; 120, 40 and 5 psig

at Brockton; and 100, 55 and 5 psig at

West Roxbury. Steam uses at all three

facilities include space heating, water

heating, food preparation, equipment

sterilization, and laundry. Steam usage

ranged from 12–52 weeks per year for

the various processes. Steam losses were

valued at $5.25 per 1,000 pounds of steam

at Providence and $4.25 per 1,000 pounds

of steam at Brockton and West Roxbury.

Existing Technology Description

Trap-specific characteristics must be collected via inspection and evaluation to

accurately estimate annual steam loss.

The size, type, manufacturer, and model

should be identified. This information is

used to identify the effective orifice size

if the trap has failed in a fully open condition. Interpretation of trap operating

condition via one of the methods previously described is required to judge

whether a trap is operating correctly or

not, if it has failed in an open or closed

position, and the degree of failure if less

than fully open. Accurately determining the effective orifice size for a trap

determined to have failed in an open or

partly open position requires detailed

knowledge of the trap design (acquired

from the trap vendor) and experience

evaluating traps. Thus, it may be more

cost-effective to hire the services of a

company that specializes in trap testing

and evaluation than to conduct the 

assessment with in-house personnel.

Sites with larger steam systems and

more traps are more likely candidates

for developing their own capabilities,

but availability of maintenance staff is

often the limiting factor.

The trap inspection and evaluation

company contracted for the VA assessment identified the trap location, manufacturer, type, model (in some cases),

nominal pipe diameter, inlet and outlet

pressure, steam supply control, and

steam service for each steam trap. Again,

knowledge of steam service (e.g., water

heating, space heating, equipment sterilization, main and header drip legs, etc.)

and steam supply control to the service

is essential for estimating the number 

of hours a year that each trap will be

energized and potentially leaking. 

The balance of the information collected is oriented toward determining

the leak rate.

Providence has by far the greatest number of traps of the three facilities with

1109 units. Brockton and West Roxbury

have 202 and 95 traps, respectively. 

Unfortunately, the trap inspection was

conducted in the spring at Providence

and summer at Brockton and West

Roxbury when most, if not all of the

traps servicing space-heating equipment were not in use. Thus, it was not

possible to test approximately 70% of the

traps at Providence and approximately

40% of the traps at Brockton and West

Roxbury. Of the remaining traps, 51, 47,

and 5 were found to have failed in the

open position at Providence, Brockton,

and West Roxbury, respectively. Among

those determined to have failed opened,

each was classified as leaking at a low,

medium, or high rate relative to the leak

rate for each trap if it failed fully open.

Thus, the estimated annual leak rate is a

function of the trap orifice if fully open,

the degree of openness of the failure,

the differential pressure across the trap,

and the number of hours the trap is 

energized.

New Technology Equipment 

Selection

The energy savings in this case study

come from repairing and replacing

steam traps that have failed in a fully or

partly open position and were leaking

steam into the condensate system. No

change in steam trap technology was

considered. Instead, a change in maintenance practice was recommended. Selection of the steam trap testing equipment

is not nearly as important as the decision

to conduct testing. Using the most rudimentary trap testing equipment will

probably cut trap-related steam losses

by more than 50%. Using any of the

testing equipment described in this

Federal Technology Alert will probably

cut trap-related steam losses by at least

75%. In general, more sophisticated

testing equipment and more frequent

testing is warranted for larger traps 

operating at higher pressures, where the

potential steam loss rate is the highest.

Savings Potential

The savings potential for each trap can

be calculated from an estimate of the

orifice size associated with a leaking

trap (i.e., the size of the hole that steam is

leaking through, which will be less than

or equal to its orifice size when a trap is
16

FEDERAL ENERGY MANAGEMENT PROGRAM

fully open), the steam pressure, the fraction of the year that the trap is energized,

and the boiler efficiency. Figure 10 shows

how annual energy losses vary with

equivalent hole (orifice) diameter and

steam pressure.

Annual steam losses were estimated 

to be 3,561, 16,591, and 733 thousand

pounds per year at the Providence,

Brockton, and West Roxbury medical

centers, respectively. Steam was valued

at $5.25 per thousand pounds at Providence and $4.25 per thousand pounds

at Brockton and West Roxbury. Thus,

the total annual costs of the losses (and

the expected annual savings if fixed)

were estimated to be $18,695 at Providence, $70,511 at Brockton, and $3,117

at West Roxbury.

Life-Cycle Costs

Trap inspection and evaluation at the

VA medical centers was included as part

of broader energy audits addressing

other components of the steam generation and distribution systems. The traprelated portion of the energy audit costs

were estimated by the contractor to average $9.70 per trap, while trap replacement was estimated to cost $94 each.4

Thus, total trap replacement costs were

estimated to be $5076, $4512, and $470

at Providence, Brockton, and West

Roxbury, respectively. Combining these

investment costs with the annual savings

estimates noted above yields payback

periods of 0.27, 0.06, and 0.15 years for

the three medical centers in the same

order. Note that “sunk” cost associated

with trap testing does not figure into the

economic assessment affecting the decision to replace the traps or not. Also note

that this assessment focuses on the costs

and savings of the traps identified as

failed and needing replacement. The 

estimated savings for these traps will

continue until these traps start to fail.

The average trap lasts for about 5 years,

with some lasting longer and some 

failing sooner.

The Technology in

Perspective

Proactive steam trap management 

programs have proven themselves to 

be cost-effective. The most important

decision is making a commitment to

implement a program; the specific testing equipment chosen is of lesser importance. Still, site-specific steam system

and maintenance resource characteristics (e.g., number and size of traps, availability of capital and labor) will affect

the preferred testing technology. In the

future, continued improvement of performance assessment technologies

should allow even greater cost-effective

energy savings.

The Technology’s Development

Sight, sound, and temperature measurements have been used to assess the performance of steam traps since steam

traps were invented, but the measuring

technology has evolved over the years.

Equipment using a fourth method,

based on the conductivity of the fluid 

at a specific point in the pipeline, has

been developed in recent years.

In steam systems without condensate

return, steam leaking past a trap is 

directly visible. With condensate return,

a test tee and two valves (one to isolate

the trap being tested from the influence

of other traps, the other to provide an

outlet for viewing the fluid downstream

of the trap being tested) are all that’s 

required. Thus, the standard technology for conducting a visual test has 

remained unchanged since steam traps

were invented. Sight glasses provide an

alternative approach to visual assessment that can be used without affecting

system operation, but are prone to fouling in some service conditions.

Sound measurement has progressed

from a screwdriver to a more comfortable mechanic’s stethoscope to ultrasonic listening devices. The former two

assist with hearing sounds in the normal

audible range of the human ear, while

the latter detects normally inaudible

sounds of higher frequency and converts the signal into audible sounds.

Simpler ultrasonic listening devices are

tuned to a fixed frequency or frequency

range, while more advanced models 

allow tuning to a specific frequency or

frequency range. More recently, acoustic

signatures representative of properly

working and failed traps have been

stored in the memory of ultrasonic listening devices for comparison with current readings. This allows the ultrasonic

instrument to provide a diagnosis of

trap condition without relying on the

experience of the instrument user.

Temperature measurement tools have

also progressed significantly over 

the years. Although a gloved-hand or

squirt bottle may be adequate in some

situations, much better accuracy can be

easily achieved. Temperature measurement has progressed from these original

“ballpark” approaches to temperaturesensitive materials that change color

with temperature to several types of

contact and non-contact devices. Earlier

instruments were generally thermometers (i.e., devices that measure temperature based on the thermal expansion of

various materials). More advanced contact devices are now based on either the

thermoelectric potential of two dissimilar metals (thermocouple) or the variation in electrical resistance of a metal

with temperature (thermistor). Contact

temperature measurement is often 

coupled with ultrasonic measurement

to provide an integrated steam trap testing unit. Non-contact devices allow the

freedom and comfort of measuring 

temperature from a distance based on

the thermal radiation emitted from an

object’s surface. The radiation entering

a non-contact pyrometer is either focused

on a heat-sensitive element such as a

4 Note that $94 was estimated per trap 

replaced, while the figures in Table 1 are

based on the total trap population. Thus, 

the figure of $40/trap in Table 1 incorporates

assumptions about the fraction of traps initially needing replacement and the cost per

replacement.
17

FEDERAL ENERGY MANAGEMENT PROGRAM

thermocouple or thermistor (radiation

or infrared pyrometer) or its intensity is

compared to that of reference element

(optical pyrometer).

Conductivity measurement is a relatively

new approach for evaluating steam traps.

A probe inserted into the pipeline can

easily distinguish between the conductivity of steam or condensate. The probe

must be positioned at a location where

normally it would be covered by condensate, but failure would cover it with

steam or vice versa. Special sensing

chambers create a flow path and precise

point for inserting a probe. Conductivity

probes, also often coupled with contact

temperature measurement devices, can

be wired to a central, remote monitoring

device that receives signals from many

probes. This minimizes subsequent data

collection efforts, but does cost more to

purchase and install than ultrasonic test

equipment, which is portable.

Technology Outlook

Steam trap testing equipment is relatively mature, but evolutionary progress

is expected to continue. Advances in

electronics have spurred the development of new steam trap testing equipment and reduced the cost of basic

ultrasonic and temperature measurement instruments. This trend is expected

to continue. Future advances in ultrasonic measurement might reduce costs

enough to allow meters to be permanently attached to individual steam

traps like conductivity probes and 

sensing chambers. This would allow

central, remote monitoring of ultrasonic

measurements.

Manufacturers

The number of technologies that could

potentially be applied to the evaluation

of steam trap performance is extensive.

In general, the manufacturer list that

follows was limited to those making technologies that are peculiar to the evaluation of steam traps. This excluded, for

example, all temperature-measuring 

devices. An exception to this general 

exclusion was made for ultrasonic testing equipment, however.

Steam trap evaluation technologies and

associated manufacturers were identified

by contacting steam trap and ultrasonic

testing equipment manufacturers listed

in product directories published by 

Thomas Register, Chemical Engineering,

Energy Products, Heating/Piping/AirConditioning, Energy User News, and

Consulting Specifying Engineer. We also

conducted searches of Internet web sites

and library databases. Despite our efforts,

it is practically impossible to ensure that

all manufacturers of steam trap performance assessment equipment have

been identified. In fact, given the broad

scope of potentially applicable equipment, some manufacturers have surely

been missed. To those, we extend our

apologies.

The search process identified 13 products offered by 10 companies in four 

generic categories. The four categories

were 1) ultrasonic listening devices

(with or without accompanying temperature-measuring devices) with builtin diagnostic capability, 2) conductivity

measuring devices (with or without 

accompanying temperature-measuring

devices) with built-in diagnostic capability, 3) ultrasonic listening devices

(tunable or fixed frequency bandwidth, with or without accompanying

temperature-measuring devices) without built-in diagnostic capability, and 

4) a sight glass for visual determination of steam trap condition. A detailed

description of each product, including

manufacturer contact information, is

presented in Appendix A.

The 10 companies offering these steam

trap products are:

– Armstrong International, Inc.

– CTRL Systems, Inc.

– Electronics For Industry, Inc.

– GESTRA, Inc.

– Mitchell Instrument Co.

– Spirax Sarco, Inc.

– Superior Signal Company, Inc.

– TLV CORPORATION

– Triple 5 Industries, LLC.

– UE Systems, Inc.

Who is Using the Technology

Thousands of ultrasonic listening 

devices (without built-in steam trap 

diagnostics) have been sold to Federal

and non-Federal customers. However,

these devices can be used for evaluating an extremely broad range of other

equipment, so the number used for

evaluating steam traps is unknown. 

Approximately 150 ultrasonic testing

systems with built-in steam trap diagnostics also have been sold. Again, the

specific number of Federal applications

is unknown. Sales data for sight glasses

and conductivity-based testing systems

were unavailable. The following Federal

contacts were identified by the manufacturers listed above as users of one or

more of the steam trap monitoring 

technologies described in this Federal

Technology Alert.

Ted Tomaliwski

National Institute of Standards 

and Technology

Quince Orchard and Clopper Road

Gaithersburg, Maryland

301-975-6983

George Spencer

CIS Services

440 Baldwin

Eddystone, Pennsylvania

800-745-9981

Charles McMullin

Whiteman Air Force Base

Building 410

Knobnoster, Missouri

660-687-5095

Peter Palamidis

Brookhaven National Laboratory

Building 097

Upton, New York

516-344-2462
18

FEDERAL ENERGY MANAGEMENT PROGRAM

For Further Information

Associations

International District Energy 

Association

1200 19th Street, N.W. Suite 300

Washington, DC 20036-2412

Tel: 202-429-5111

Fax: 202-429-5113

www.energy.rochester.edu/idea/

American Boiler Manufacturers 

Association

950 N. Glebe Road

Suite 160

Arlington, VA 22203-1824

Tel: 703-522-7350

Fax: 703-522-2665

www.abma.com

Council of Industrial Boiler Owners

6035 Burke Centre Parkway

Suite 360

Burke, VA 22015

Tel: 703-250-9042

Fax: 703-239-9042

www.cibo.org

Clearinghouse

Steam Challenge Clearinghouse

P.O. Box 43171

925 Plum Street, SE

Olympia, WA 98504-3171

Tel: 800-862-2086

Fax: 360-586-8303

Steamline@energy.wsu.edu

Other Web Sites

U.S. Department of Energy, Office 

of Industrial Technologies Steam Challenge Program 

www.oit.gov/steam

Alliance to Save Energy 

www.ase.org

Armstrong Steam Library 

www.armstrong-intl.com/university/su.html

Guides and Handbooks

Armstrong International, Inc. 1995.

Steam Conservation Guidelines for Condensate Drainage. Three Rivers, Michigan.

McCauley, J.F. 1995. The Steam Trap

Handbook. The Fairmont Press, Inc.

Lilburn, Georgia.

Naval Facilities Engineering Service

Center. 1998. Steam Traps—An Overview.

Port Hueneme, California.

Spirax Sarco, Inc. 1997. Design of Fluid

Systems. Allentown, Pennsylvania.

TLV CORPORATION. 1997. Managing

the Steam Trap Population. Charlotte,

North Carolina.

Yarway Corporation. 1984. Industrial

Steam Trapping Handbook. Blue Bell,

Pennsylvania.

References

Avallone, E.A., and T. Baumeister, editors. 1986. Marks’ Standard Handbook

for Mechanical Engineers. Ninth 

Edition. McGraw-Hill Book Company,

New York.

David, T. 1981. “Springing the Trap.”

Energy Manager, October 1981.

Federal Energy Management Program.

1996. Heating with Steam at Veterans 

Administration Medical Centers. U.S. 

Department of Energy, Washington, D.C.

Fischer, D.W. 1995. “Assessing the 

Impact of Energy Losses in Steam Systems.” Plant Engineering, July 10, 1995.

Garcia, E., and R. Gaggioloi. 1986. “A

Discussion on Steam Trap Management

Programs and Their Return.” Proceedings, 1986 ASME Winter Meeting. ASME,

New York.

Hooper, F.A., and R.D. Gillette. 1997.

Comparison of Three Preventative Maintenance Strategies for Steam Trap Systems.

Steam Conservation Systems, East

Greenwich, Rhode Island.

Johnson, M., and L. Lawlor. 1985. “Steam

trap replacement program initiated by

pharmaceutical plant. Chemical Processing (April 1985) pp. 22-23.

Lane, J. 1983. “Cut energy losses and

improve control with steam trap inspection teams.” Canadian Chemical Processing.

Vol. 67, No. 2, pp. 27-28.

Miller, J.A. 1985. “A Minimum Life Cost

Strategy for Steam Trap Maintenance.”

ASHRAE Transactions, Vol. 91, Part 1B.

ASHRAE, Atlanta, Georgia.

Pychewicz, F.S. 1985. “Steam Traps—

The Oft Forgotten Energy Conservation

Treasure.” Published in the Proceedings

of the 1985 Industrial Energy Technology

Conference and Exhibition. Public Utility

Commission of Texas, Austin, Texas.

Tuma, S.L., and D. Kramer. 1988. “Steam

System Testing, Maintenance, and Energy

Conservation: A Case History. Integration

of Efficient Design Technologies. Fairmont

Press, Lilburn, Georgia.

Vallery, S.J. 1981. “Setting Up a Steam

Trap Standard.” Chemical Engineering

Vol. 88, No. 3, pp. 92-98.

Vallery, S.J. 1982. “ Are your steam traps

wasting energy?” Process Energy Conservation. McGraw-Hill Publications Co,

New York.
19

FEDERAL ENERGY MANAGEMENT PROGRAM

Appendixes

Appendix A: Steam Trap Monitoring Equipment Information

Appendix B: Federal Life-Cycle Costing Procedures and the BLCC Software
20

FEDERAL ENERGY MANAGEMENT PROGRAM

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21

FEDERAL ENERGY MANAGEMENT PROGRAM

Appendix A

Steam Trap Monitoring Equipment Information

Manufacturer: Armstrong International, Inc.

Address: 816 Maple Street, PO Box 408, Three Rivers, MI 49093

Phone: 616-273-1415

Fax: 616-278-6555

Contact: Scott French

Product Name: Trap Scan/Trap Alert

Description: Trap Scan is a remotely operated steam trap testing system with probes that are integrated with the body of the steam

trap. Signals from individual traps/probes are communicated via wire to zone modules and from there to a single central processing

unit (CPU) provided by Armstrong or a programmable logic controller (PLC) provided by the user. Trap Alert uses the same probe

as the Trap Scan, but does not forward a signal to a central processing unit. Instead, the external portion of the probe is integrated

with a visual signaling device.

Operating Mechanism: The probe measures the temperature and conductivity within the steam trap at a location near the bottom of

an inverted bucket. The conductivity measurement indicates whether the measurement point is within steam or condensate. During

normal operation, the probe should be covered with condensate, indicating that steam is not leaking or blowing through the trap. If

the temperature is also within an acceptable preset range, normal operation would be indicated. If the probe is covered with condensate, but the temperature is below the preset range, the trap is presumed to have failed closed or be otherwise blocked. If the probe

indicates it is covered by steam, the trap is presumed to be leaking or failed open, unless the trap is also cold. In this latter combination, the trap is probably serving an inactive device and has lost its prime.

How Applied: Trap Scan data collection is initiated by pressing a button on the CPU/PLC. The CPU/PLC polls steam traps by zone

to determine temperature and conductivity at the probe tip. One zone module can take signals from up to eight traps, and up to 25

zones can feed into one CPU. The CPU processes the data and interprets each steam trap’s condition. The CPU comes with an RS232 serial communications port (for connection to a computer), and either a parallel communications port for use with an external

printer or an optional integrated printer. Alternatively, the output could be viewed on a PLC monitor. Trap Alert for indoor service is

activated by focusing a flashlight beam on the unit’s photodetector. The beam activates the unit’s batteries, which power three small

indicator lights. A green light indicates a good condition; yellow means the trap is cold; red signals a leaking or blowing trap. Trap

Alert for outdoor service is activated by a magnetic field (almost any type of magnet can be used). When activated, a bulb lights for

1-2 seconds if the trap is okay, for 10-15 seconds if the trap has lost its prime or is leaking or blowing steam, or flashes on and off for

10-15 seconds if the trap is cold.

Installation Requirements: The Trap Scan probe is screwed into the bottom of an inverted bucket steam trap. Wires are run from the

external tip of each probe to the zone module and from each zone module to the CPU/PLC. Additional wiring or other communication hardware would be required to connect the Trap Scan CPU to a personal computer. 120 VAC power must also be provided to

the CPU/PLC. The CPU, zone modules, probes, and probe interfaces are provided by Armstrong. The user supplies communication

and power wiring, and any additional communication hardware for connecting to a computer. If the user chooses, they can provide

their own PLC in lieu of the Trap Scan CPU, but would need a Trap Scan power supply module instead.

Application Limitations: Trap Scan is compatible with Armstrong Series 800 cast iron and Models 1811 and 2011 stainless steel inverted bucket traps. The unit is designed for services up to 400 psig and temperatures up to 450°F, indoors or outdoors.

Experience: Units sold/installed: About 75 Trap Scan systems are in use, ranging from 10 to 200 probes, as well as thousands of

Trap Alerts.

Federal customers: Army

Federal references: None identified.

Purchase Cost: $150 for Trap Alert.

Warranty: Trap Scan and Trap Alert are covered by a 1-year warranty.
22

FEDERAL ENERGY MANAGEMENT PROGRAM

Installation Labor/Material/Cost: The incremental costs to install a Trap Alert steam trap are negligible compared to a standard

steam trap. The total installed costs (purchase plus installation) for Trap Scan systems (including the trap) range from $400-700 

per trap.

Operating Labor/Material/Cost: A single Trap Scan system can check the condition of up to 200 steam traps in a few minutes. No

routine maintenance is required.

Manufacturer: CTRL Systems, Inc.

Address: 1902 Twin House Road, Oxford, PA 19363

Phone: 610-932-7006

Fax: 610-998-0588

Contact: Dean Smith

Product Name: Ultraphonic Detector Model 101

Description: The Ultraphonic is a portable, hand-held instrument for detecting and measuring ultrasonic sounds. Optional 

software allows collection and subsequent analysis of historical measurements.

Operating Mechanism: The flow of steam or condensate through a steam trap creates turbulence, which results in ultrasound. 

Ultrasonic frequencies between 20 and 100 kHz are detected, measured, and converted to audible frequencies between 100 Hz 

and 3 kHz. By converting the ultrasonic frequencies generated by an operating steam trap into the audible range, the Ultraphonic

allows users to hear through a headphone and see on a meter sound characteristics that allow an assessment of a steam trap’s 

condition.

How Applied: The tip of the Ultraphonic stethoscope is held on the steam trap, allowing ultrasonic frequencies to be measured and

converted to audible sounds. The unit operates in a fixed frequency range. The user must be trained to identify and differentiate 

between the sounds expected from a properly functioning trap and the sounds from a trap that has failed close, failed open, or is

leaking steam.

Installation Requirements: The Ultraphonic stethoscope and headphones are portable. No installation is required.

Application Limitations: Although the Ultraphonic can be applied to any type of trap, the sounds associated with properly 

working and failed traps vary with the type of trap, so training on the different types of traps installed at the user’s facility is 

required. One user estimated the training time at as little as 1-2 hours. In addition, the tip of the stethoscope must be placed in direct

contact with the steam trap, which may not always be possible. 

Experience: Units sold/installed: Approximately 800 units have been sold.

Federal customers: Approximately 25-30% of the 800 units have been sold to military customers.

Federal reference: Ted Tomaliwski works at the central steam, chilled water, and compressed air plant for the National

Institute of Standards and Technology in Gaithersburg, Maryland. Steam is produced primarily for facility heating.

The Ultraphonic 101 is used to check for air leaks and malfunctioning steam traps, primarily low-pressure traps in the

plant. He says the unit “works well and is easy to use.” They also use a surface temperature probe to evaluate trap

performance.

Ted Tomaliwski, National Institute of Science and Technology, Quince Orchard and Clopper Road, Gaithersburg, MD

20899, 301-975-6983.

Purchase Cost: $1995 for Model 101, not including optional software.

Warranty: The Model 101 is covered by a 1-year warranty.

Installation Labor/Material/Cost: There are no costs associated with installing the equipment, but users will need to be trained to

distinguish the sounds of properly functioning traps from the sounds of different failure modes. The length of training depends on

the user’s familiarity with steam trap principles, but should require no more than 2-3 hours of classroom instruction, plus a hands

on field session testing actual steam traps. CTRL has created a CD-ROM training tool for the system. They estimate 1-2 hours 

training plus 1-2 days of field tests to become familiar with steam trap testing.

Operating Labor/Material/Cost: Mostly the time required to walk from one steam trap location to the next and record the test 

results; sound measurement is instantaneous.
23

FEDERAL ENERGY MANAGEMENT PROGRAM

Manufacturer: Electronics For Industry, Inc. 

Address: 18633 S.W. 105th Ave. Miami, FL 33157

Phone: 305-233-1640

Fax: 305-233-1776

Contact: George Harris

Product Name: W-7 Microsonic Detector

Description: The Microsonic Detector is a portable, hand-held instrument for detecting and measuring ultrasonic sounds. The 

W-7 model is a hand-held “gun” that incorporates a meter indicating the strength of the noise. The EL-300 microsonic stethoscope is

also offered, but does not incorporate the visual meter reading.

Operating Mechanism: The flow of steam or condensate through a steam trap creates turbulence, which results in ultrasound. 

Ultrasonic frequencies between 20 and 100 kHz are detected, measured, and converted to audible frequencies between 100 Hz 

and 3 kHz. By converting the ultrasonic frequencies generated by an operating steam trap into the audible range, the W-7 allows 

users to hear through a headphone and see on a meter sound characteristics that allow an assessment of a steam trap’s condition.

How Applied: The tip of the W-7 gun is held on the steam trap, allowing ultrasonic frequencies to be measured and converted to

audible sounds. The W-7 listens for noise in the 40 kHz region. The user must be trained to identify and differentiate between the

sounds expected from a properly functioning trap and the sounds from a trap that has failed close, failed open, or is leaking steam.

Installation Requirements: The W-7 gun and headphones are portable. No installation is required.

Application Limitations: Although the W-7 can be applied to any type of trap, the sounds associated with properly working and

failed traps varies with the type of trap, so training on the different types of traps installed at the user’s facility is required. In addition, the most accurate results will be achieved when the tip of the gun can be placed in direct contact with the steam trap, which

may not always be possible. Although an attachment will allow measurement of airborne signals, it’s often difficult to distinguish

the source of the signal when operating in this mode, especially in a process plant environment where there are many signal sources.

Experience: Units sold/installed: Manufactured since 1967, with sales to many DoD sites.

Federal customers: None identified.

Federal references: None identified.

Purchase Cost: $699 for W-7 Microsonic Detection Kit, which includes detector body, leak and stethoscope plug-in modules, rubber

focusing extension, ultrasonic tone generator, headset, and carrying case. 

Warranty: The W-7 is covered by a 1-year warranty.

Installation Labor/Material/Cost: There are no costs associated with installing the equipment, but users will need to be trained to

distinguish the sounds of properly functioning traps from the sounds of different failure modes. The length of training depends on

the user’s familiarity with steam trap principles, but should require no more than 2-3 hours of classroom instruction, plus a hands

on field session testing actual steam traps. 

Operating Labor/Material/Cost: Mostly the time required to walk from one steam trap location to the next and record the test 

results; sound measurement is instantaneous.

Manufacturer: GESTRA, Inc.

Address: 10 York Avenue; W. Caldwell, NJ 07006

Phone: 973-403-1556

Fax: 973-403-1557

Contact: Ed Ilg

Product Name: Vaposcope VK

Description: A Vaposcope is a double-sided sight glass that allows visual supervision of flow conditions in pipelines.

Operating Mechanism: Where steam and condensate are present, the steam will pass over the top of the condensate because of its

lower density. The internals of the Vaposcope include a flow deflector and condensate basin to aid recognition of the mixture of

steam and condensate within the pipe (see Figure 7 in the main text). Steam and condensate are forced through the basin by the 
24

FEDERAL ENERGY MANAGEMENT PROGRAM

deflector. Normal operation is indicated by slight turbulence and a condensate level that just covers the bottom of the deflector.

Higher steam flow rates, indicating a leaking or blowing trap, will create more turbulence and depress the condensate level below

the deflector. If no turbulence is seen and the deflector is completely covered with condensate, a downstream blockage has occurred,

potentially by a failed or undersized steam trap.

How Applied: The Vaposcope is installed directly in a pipeline like a valve. Flow conditions are manually observed through the site

glass as described above to judge the condition of nearby steam traps.

Installation Requirements: An existing pipeline would have to be cut open and a short section taken out to allow the Vaposcope to

be inserted. Flanges would have to be welded to the two pipe ends or the Vaposcope would have to be welded directly into the pipeline. A threaded version is also available.

Application Limitations: Vaposcopes are available for application at pressures up to 580 psig in nominal pipe diameters of 

0.5-2 inches. Applications will be limited to locations where space exists to insert the Vaposcope into the pipe and where physical

access allows visual inspection.

Experience: Units sold/installed: Thousands of Vaposcopes have been sold.

Federal customers: None identified.

Federal references: None identified.

Purchase Cost: $518-946. 

Warranty: The Vaposcope is covered by a 1-year warranty.

Installation Labor/Material/Cost: Same as installing a steam trap.

Operating Labor/Material/Cost: The time required to walk from one Vaposcope location to the next and record the

observation/condition assessment.

Manufacturer: GESTRA, Inc.

Address: 10 York Avenue; W. Caldwell, NJ 07006

Phone: 973-403-1556

Fax: 973-403-1557

Contact: Ed Ilg

Product Name: Test Set VKE

Description: The Test Set is a conductivity measuring device mounted in its own test chamber.

Operating Mechanism: The difference in steam and condensate conductivity is used to identify the presence of steam or condensate

at the sensor.

How Applied: The test set is installed upstream of a steam trap. During normal operation, the sensor is immersed in condensate. If

the steam trap is leaking sufficient steam, the increased steam flow will result in steam covering the sensor. The sensor is read by

temporary electrical connection to a portable test unit or permanent connection to a remote test unit. The remote unit is capable of

monitoring up to 18 sensors. The portable test unit shows a green light if condensate is detected and a red light if steam is detected.

The remote unit also shows a red light if steam is detected, but no light if condensate is detected. Note that the steam trap could be

failed shut, flooding the sensor with condensate, but indicating that operation is normal. Therefore, this device must be used in conjunction with a temperature measurement to make sure that flooding has not occurred. Condensate backup is indicated by a temperature that is lower than expected for normal saturated steam conditions.

Installation Requirements: An existing pipeline would have to be cut open and a short section taken out to allow the Test Set to be

inserted. Flanges would have to be welded to the two pipe ends or the Test Set would have to be welded directly into the pipeline.

The remote unit would require installation of connecting wiring.

Application Limitations: Test Sets are available for application at pressures up to 465 psig. Applications will be limited to locations

where space exists to insert the Test Sets into the pipe. Relatively easy physical access is desirable for manual inspection.

Experience: Units sold/installed: Hundreds of Test Sets have been sold.

Federal customers: None identified.

Federal references: None identified.
25

FEDERAL ENERGY MANAGEMENT PROGRAM

Purchase Cost: $3200-3800 for remote test unit. The manual test unit costs $400 and the test chambers range from $350–400, depending on the fitting size.

Warranty: The Test Set VKE is covered by a 1-year warranty.

Installation Labor/Material/Cost: Chamber installation is about the same as installing a steam trap. Add wire and conduit costs of

about $0.15 per foot each, plus labor to lay conduit.

Operating Labor/Material/Cost: Manual testing will require time to walk from one Test Set location to the next and record the observation/condition assessment. Even with the remote unit, a complete assessment of steam trap condition will require walking from

trap to trap to collect temperature data, so labor savings with the remote unit appear minimal.

Manufacturer: GESTRA, Inc.

Address: 10 York Avenue; W. Caldwell, NJ 07006

Phone: 973-403-1556

Fax: 973-403-1557

Contact: Ed Ilg

Product Name: Trap Test VKP 30 – Available in spring 1999

Description: Trap Test is a computerized steam trap management system. The system consists of a hand-held measuring transducer,

a portable computer, and Trap Test software. This is an updated version of the Trap Test VKP 20, with added features such as a

weather/shock proof case, audio output, and compatibility with a Windows operating system (previously DOS).

Operating Mechanism: Ultrasonic measurements are compared to expected measurements stored in the computer for the specific

trap being tested. The computer judges whether the steam trap is operating correctly or not, rather than relying on the judgment of

the testing personnel. Data collected by Trap Test can be downloaded later to a personal computer via an accessory cable if desired.

How Applied: Data are collected by placing the transducer tip on the steam trap. The specific point depends on the trap type and

make. Ultrasonic vibrations are converted by the transducer to electrical pulses and transmitted as digital pulses to the computer.

The signal is presented on a screen and can be printed or stored electronically for future comparisons with additional tests. Data

collection requires about 10-25 seconds. Based on the ultrasonic signal recorded, the computer determines whether the steam trap is

leaking steam or not. Data can be stored for up to 1100 traps per removable data storage cards. In addition to diagnostic results, survey dates, trap characteristics, location information, and tester comments can be stored. The software will also automatically prepare

repair orders. Universal application with all trap types and makes is possible.

Installation Requirements: The Trap Test hardware is portable. No installation is required.

Application Limitations: The Trap Test measuring transducer must be placed on the steam trap, so immediate physical access to the

trap being tested is required. Training time for the Trap Test is estimated by the vendor to be about 10 hours.

Experience: Lab tests: The VKP 30 is currently in lab testing. Since most of the components are adapted from the VKP 20, or are

purchased components used in other systems (i.e. computer and case) the system is expected to require little additional

field testing.

Units sold/installed: About 100 Trap Test VKP 20 systems were installed.

Federal customers: None Identified.

Federal references: None Identified.

Purchase Cost: $5,000 – 7,000. 

Warranty: The Trap Test VKP is covered by a 1-year warranty.

Installation Labor/Material/Cost: None.

Operating Labor/Material/Cost: The time required to walk from one steam trap to the next and record the observation/condition

assessment.
26

FEDERAL ENERGY MANAGEMENT PROGRAM

Manufacturer: GESTRA, Inc.

Address: 10 York Avenue; W. Caldwell, NJ 07006

Phone: 973-403-1556

Fax: 973-403-1557

Contact: Ed Ilg

Product Name: Vapophone VKP-Ex

Description: The Vapophone is a portable, hand-held instrument for detecting and measuring ultrasonic sounds.

Operating Mechanism: The flow of steam through a steam trap creates turbulence, which results in ultrasound. Steam flow ultrasonic frequencies between 40 and 60 kHz are detected, measured, converted to an electronic signal, and displayed on an analog

meter. The meter reading is used to make an assessment of a steam trap’s condition.

How Applied: The tip of the Vapophone probe is held on the steam trap, allowing ultrasonic frequencies to be measured and converted to an analog meter reading. The unit operates at a fixed frequency range. The magnitude of the analog meter reading is proportional to steam leakage. The user must first calibrate the Vapophone against a steam trap that is known to leak, preferably one

that is similar to others to be tested.

Installation Requirements: The Vapophone is portable. No installation is required.

Application Limitations: Although the Vapophone can be applied to any type of trap, the sounds associated with properly working

and failed traps varies with the type of trap, so calibration of the meter for the different types of traps installed at the user’s facility

is required. Training the operator to recognize failures in different types of traps is estimated by the manufacturer to require from 

5-8 hours. In addition, the probe must be placed in direct contact with the steam trap, which may not always be possible. 

Experience: Units sold/installed: Hundreds of Vapophones have been sold.

Federal customers: None identified.

Federal references: None identified.

Purchase Cost: $1545.

Warranty: The Vapophone VKP-Ex is covered by a 1-year warranty.

Installation Labor/Material/Cost: There are no costs associated with installing the equipment, but users will need to be trained to

distinguish the sounds of properly functioning traps from the sounds of different failure modes. The length of training depends on

the user’s familiarity with steam trap principles, but should require no more than 2-3 hours of classroom instruction, plus a handson field session testing actual steam traps.

Operating Labor/Material/Cost: Mostly the time required to walk from one steam trap location to the next and record the test 

results; sound measurement is instantaneous.

Manufacturer: Mitchell Instrument Co.

Address: 1570 Cherokee Street, San Marcos CA 92069

Phone: 760-744-2690

Fax: 760-744-0083

Contact: Chris 

Product Name: Ultrasonic Noise Detector

Description: The Ultrasonic Noise Detector (UND) is a portable, hand-held instrument for detecting and measuring ultrasonic

sounds, and measuring surface temperature.

Operating Mechanism: The flow of steam or condensate through a steam trap creates turbulence, which results in ultrasound. 

Ultrasonic frequencies between 20 and 200 kHz are detected, measured, and converted to audible frequencies between 100 Hz 

and 3 kHz. By converting the ultrasonic frequencies generated by an operating steam trap into the audible range, the UND allows

users to hear through a headphone and see on a meter sound characteristics that allow an assessment of a steam trap’s condition.

The contact sensor incorporates a thermocouple that allows simultaneous temperature measurement. Digital readings of the monitoring frequency (kHz), sound level, (dB), and temperature are provided. An analog measure of sound level is also displayed. 
27

FEDERAL ENERGY MANAGEMENT PROGRAM

How Applied: The tip of the UND “gun” is held on the steam trap, allowing ultrasonic frequencies to be measured and converted to

audible sounds and temperature measurement via a thermocouple. The UND can be tuned in the full-range mode to any frequency

within 20-200 kHz. For better results, the instrument would be more commonly operated in the limited-range mode, which allows tuning to frequencies within 36-44 kHz. This allows differentiation between steam and condensate flows while reducing interference from

other ultrasonic signals and ignoring frequencies outside of this range. The user must be trained to identify and differentiate between

the sounds expected from a properly functioning trap and the sounds from a trap that has failed close, failed open, or is leaking steam. 

Installation Requirements: The UND gun and headphones are portable. No installation is required.

Application Limitations: Although the UND can be applied to any type of trap, the sounds associated with properly working and

failed traps varies with the type of trap, so training on the different types of traps installed at the user’s facility is required. In addition, the most accurate results will be achieved when the tip of the gun can be placed in direct contact with the steam trap, which

may not always be possible. Although an attachment will allow measurement of airborne signals, it’s often difficult to distinguish

the source of the signal when operating in this mode, especially in a process plant environment where there are many signal sources.

The contact sensor may be exposed to 500°F conditions continuously or up to 800°F intermittently.

Experience: Units sold/installed: Several hundred Ultrasonic Noise Detectors are sold each year.

Federal customers: None identified.

Federal references: None identified.

Purchase Cost: The complete package, including ultrasonic gun, airborne sensor, contact sensor with temperature capability, test

tone generator, battery charger, soundproof headphones, flexible focus sensor adapter, and carrying case costs $4200. The cost for

individual components of the package are: ultrasonic gun: $2900; airborne sensor: $150; contact sensor: $450; test tone generator:

$105; battery charger: $60; headphones: $395; flexible focus sensor adapter: $10.

Warranty: The Ultrasonic Noise Detector is covered by a 1-year warranty.

Installation Labor/Material/Cost: There are no costs associated with installing the equipment, but users will need to be trained to

distinguish the sounds of properly functioning traps from the sounds of different failure modes. The length of training depends on

the user’s familiarity with steam trap principles, but should require no more than 2-3 hours of classroom instruction, plus a hands

on field session testing actual steam traps.

Operating Labor/Material/Cost: Mostly the time required to walk from one steam trap location to the next and record the test results;

sound measurement is instantaneous.

Manufacturer: Spirax Sarco, Inc.

Address: 1150 Northpoint Boulevard, Blythewood, SC 29016

Phone: 803-714-2000

Fax: 803-714-2200

Contact: Dennis Kacsur

Product Name: Spira-Tec

Description: The Spira-Tec steam trap fault detection system consists of a sensing chamber, sensor, and a portable or remotely 

installed monitor connected by cable for determining temperature and the presence of steam or condensate. Manual or automatic

remote units are available that are able to serve up to 12 and 16 steam traps, respectively.

Operating Mechanism: The Spira-Tec sensor measures the temperature and conductivity of the fluid present at the measuring point

in the sensing chamber. Differences in conductivity identify the fluid as steam or condensate. Under normal operation, the sensing

point is covered with condensate near the temperature of saturated steam at the local line pressure. Increased steam flow resulting

from a leaky trap will bathe the sensing point in steam rather than condensate. A drop in temperature indicates a trap that has failed

closed, is blocked, or is not in service.

How Applied: The sensing chamber with sensor is installed directly in the pipeline, just upstream from the steam trap. A portable

testing instrument is connected to the sensor. Normal operating conditions are indicated by a green light. A yellow light indicates a

trap that has failed closed or is blocked, or is out of service. A red light indicates a trap that has failed open. Up to 12 sensors may be

connected to single remote test point for more convenient testing with a portable monitor. Alternatively, an automatic monitor that

combines the functions of a remote test point and portable monitor can be connected to as many as 16 sensors. The automatic monitor may also be connected to external building operating and control systems.
28

FEDERAL ENERGY MANAGEMENT PROGRAM

Installation Requirements: An existing pipeline would have to be cut open and a short section taken out to allow the sensing chamber to be installed. Sensing chambers accommodating screwed, flanged, or welded connections are available. The manual or automatic remote units require mounting and installation of connecting wiring. The portable monitor is battery-powered, while the 

automatic monitor must be connected to an external power supply

Application Limitations: Stainless steel and ductile iron sensor chamber models are available in 1/2-, 3/4-, and 1-inch diameter 

sizes; steel models are also available in 1- and 2-inch diameter sizes. The maximum operating pressure is 464 psig and the maximum

operating temperature is the saturated steam temperature corresponding to the operating pressure.

Experience: Spira-Tec has been available in the U.S. for about 15 years.

Units sold/installed: There are thousands of Spira-Tec customers, some with thousands of sensors.

Federal customers: None identified.

Federal references: None identified.

Purchase Cost: Sensor chambers vary from $61.50 for 1/2-inch threaded ductile iron up to $1384.60 for 1-inch flanged stainless steel.

Sensors for measuring conductivity only cost $61.50. Combination conductivity and temperature sensors cost $170 for reading with

the portable monitor and $195 for reading with the automatic monitor. The portable monitor costs $311.75. The automatic monitor

costs $1770. Remote test points cost $155.40 and $398.85, respectively, for single-sensor and 12-sensor capacity models. 

Warranty: The Spira-Tec system and components are covered by a 1-year warranty.

Installation Labor/Material/Cost: The user must provide cabling connecting the sensors to remote test points or an automatic monitor. Power wiring to the automatic monitor must also be supplied. Labor is required to install these materials as well as the sensor

chambers, sensors, remote test points, and automatic monitor. Installation costs are highly site specific.

Operating Labor/Material/Cost: The time required to walk from one steam trap to the next and record the observation/condition

assessment. The time required can be reduced through the use of remote test points or an automatic monitor.

Manufacturer: Superior Signal Company, Inc.

Address: P.O. Box 96, Spotswood, NJ 08884

Phone: 732-251-0800

Fax: 732-251-9442

Contact: Paul Tashian

Product Name: AccuTrak VPE-1000

Description: The AccuTrak VPE-1000 is a portable, hand-held instrument for detecting and measuring ultrasonic sounds.

Operating Mechanism: The flow of steam or condensate through a steam trap creates turbulence, which results in ultrasound. Ultrasonic frequencies between 20 and 100 kHz are detected, measured, and converted to audible frequencies between 100 Hz and 3 kHz.

By converting the ultrasonic frequencies generated by an operating steam trap into the audible range, the AccuTrak allows users to

hear through a headphone and see on a meter sound characteristics that allow an assessment of a steam trap’s condition.

How Applied: The tip of the AccuTrak “gun” is held on the steam trap, allowing ultrasonic frequencies to be measured and converted to audible sounds. The AccuTrak can be tuned to any frequency within 20-100 kHz, which allows differentiation between

steam and condensate flows while reducing interference from other ultrasonic signals and ignoring frequencies outside of this range.

The user must be trained to identify and differentiate between the sounds expected from a properly functioning trap and the sounds

from a trap that has failed close, failed open, or is leaking steam.

Installation Requirements: The AccuTrak gun and headphones are portable. No installation is required.

Application Limitations: Although the AccuTrak can be applied to any type of trap, the sounds associated with properly working

and failed traps varies with the type of trap, so training on the different types of traps installed at the user’s facility is required. In

addition, the most accurate results will be achieved when the tip of the gun can be placed in direct contact with the steam trap, which

may not always be possible. Although an attachment will allow measurement of airborne signals, it’s often difficult to distinguish the

source of the signal when operating in this mode, especially in a process plant environment where there are many signal sources.
29

FEDERAL ENERGY MANAGEMENT PROGRAM

Experience: Units sold/installed: The AccuTrak has been sold to hundreds of customers. 

Federal customers: None identified.

Federal references: None identified.

Purchase Cost: $600. 

Warranty: The AccuTrak VPE-1000 is covered by a 1-year warranty.

Installation Labor/Material/Cost: There are no costs associated with installing the equipment, but users will need to be trained to

distinguish the sounds of properly functioning traps from the sounds of different failure modes. The length of training depends on

the user’s familiarity with steam trap principles, but should require no more than 2-3 hours of classroom instruction, plus a hands

on field session testing actual steam traps.

Operating Labor/Material/Cost: Mostly the time required to walk from one steam trap location to the next and record the test 

results; sound measurement is instantaneous.

Manufacturer: TLV CORPORATION

Address: 6701-K NorthPark Blvd.; Charlotte, NC 28216

Phone: 704-597-9070; 1-800-858-8727

Fax: 704-597-9082

Contact: Ottmar Hedemus

Product Name: TrapMan

Description: TrapMan is a computerized steam trap management system. The system includes hand-held TM5‚ hardware that incorporates ultrasonic and temperature testing equipment with TLV diagnostic logic. Accompanying TrapManager software completes

the system.

Operating Mechanism: Ultrasonic and temperature measurements are compared to expected measurements stored in the TM5 

hardware for the specific trap being tested. The hardware judges whether the steam trap is operating correctly or not, rather than 

relying on the judgment of the testing personnel. Data collected by the TM5 unit can be downloaded later to the TrapManager 

software.

How Applied: Data are collected by placing the test probe tip on the inlet side of the steam trap. Data collection requires about 

15 seconds. The TM5 unit compares measured conditions with stored conditions and returns one of the following diagnoses: 

good; small, medium, or large leak; blowing; blocked; low temperature; and temperature adjustment failure. Automatically 

diagnosed performance results can be modified manually, if necessary. Data can be stored for up to 2000 traps. In addition to 

the diagnostic result, survey date and time, surface temperature, identification number, and model can be stored. Expected operating characteristics for most traps available on the market can be accessed, including units made by Armstrong, Yarway, Spirax-Sarco,

Gestra, Nicholson, Bestobell, Velan, Clark-Reliance, Erwell, Dunham-Bush, Hoffman, Trane, Illinois, and Wright-Austin, as well as

TLV. Data are transferred from the TM5 to the TrapManager software via a communications cable supplied with the system.

Installation Requirements: The TM5 hardware is portable. No installation is required. TrapManager software is installed on the 

user’s PC. Minimum PC system requirements are a Pentium 90 CPU with 16 MB of RAM, 20 MB of hard drive capacity, a CD-ROM

drive, and a VGA monitor. TrapManager is Windows 95, Windows 98, and Windows NT compatible.

Application Limitations: The test probe must be placed on the steam trap, so immediate physical access to the trap being tested is

required. The hardware is designed to work on steam pressures ranging from 7-570 psig and surface temperatures ranging from 

32-662°F.

Experience: Units sold/installed: TrapMan systems are being used by over 150 private and public organizations. 

Federal customers: Federal users include the Army, Navy, Air Force, Veterans Administration, and Brookhaven 

National Laboratory.

Federal reference: Charles McMullin has responsibility for exterior steam lines at Whiteman Air Force Base. He has

used TrapMan for about 4 years, and considers it an improvement over temperature devices that were previously used

to assess steam trap condition. Since trap data is stored in the system it takes very little time to enter the trap I.D. number and carry out the test. Charles says that he is “well satisfied” with TrapMan. 

Charles McMullin, Whiteman Air Force Base, Building 140, Knobnoster, MO, 660-687-5095. 
30

FEDERAL ENERGY MANAGEMENT PROGRAM

Purchase Cost: The cost of the complete TrapMan system is $17,500. This includes two days of training for two people (with hotel

and meal expenses), one-year of unlimited software support, and rebates on TLV traps. 

Warranty: TrapMan is covered by a 1-year warranty.

Installation Labor/Material/Cost: Trivial installation costs for software, no installation costs for hardware; 2-4 person-days of 

training.

Operating Labor/Material/Cost: Mostly the time required to walk from one steam trap location to the next; data recording takes

only 15 seconds.

Manufacturer: Triple 5 Industries, LLC

Address: 213 Chesterfield Crosswicks Road; Trenton, New Jersey 08620

Phone: 609-298-5544

Fax: 609-298-5594

Contact: Trudy Bryson

Product Name: Sonic/Ultrasonic Leak Detectors 

Description: The Triple 5 leak detectors are portable, hand-held instruments for detecting and measuring sonic and ultrasonic

sounds. Optional equipment allows collection and subsequent transfer of data to a personal computer.

Operating Mechanism: The flow of steam or condensate through a steam trap creates turbulence, which results in ultrasound. 

Additional audible noise is also created by trap operation. Two frequency bands are monitored: 2-11 kHz in the sonic range and 20-

180 kHz in the ultrasonic range. Ultrasonic frequencies are converted to audible frequencies for the human ear. The magnitude of the

sound is also indicated via an LED display. By converting the ultrasonic frequencies generated by an operating steam trap into the

audible range, the Leak Detectors allow users to hear through a headphone and see on the LED display sound characteristics that

allow an assessment of a steam trap’s condition.

How Applied: The tip of the Leak Detector probe is held on the steam trap, allowing sonic and ultrasonic frequencies to be measured,

with the latter converted to audible sounds. The user must be trained to identify and differentiate between the sounds expected from

a properly functioning trap and the sounds from a trap that has failed close, failed open, or is leaking steam.

Installation Requirements: The Leak Detectors are portable. No installation is required.

Application Limitations: Although the Leak Detector can be applied to any type of trap, the sounds associated with properly working and failed traps vary with the type of trap, so training on the different types of traps installed at the user’s facility is required. In

addition, the most accurate results will be achieved when the tip of the gun can be placed in direct contact with the steam trap, which

may not always be possible. Although an attachment will allow measurement of airborne signals, it’s often difficult to distinguish 

the source of the signal when operating in this mode, especially in a process plant environment where there are many signal sources.

The contact probe is limited to a maximum temperature of 350°F. 

Experience: Units sold/installed: About 100.

Federal customers: None identified.

Federal references: None identified.

Commercial reference: CIS Services operates EPRI’s Monitoring and Diagnostics Center. They provide courses, including utility training, on inspecting transformers, valves, and steam traps. The 5550 Sonic/Ultrasonic Leak Detector and

5551 Data Logging Leak Detector work for all of these applications. For steam traps, CIS uses a 2-hour class followed

by a field trip, for a 1-day course. George Spencer of CIS says that these are “the best system you can buy.” The 10-180

kHz band is the best for checking steam traps, but he uses both this and the lower frequency range. He likes the battery-powered portability of the system, and claims that they are substantially faster than thermograph/temperature

systems for assessing steam traps.

George Spencer, CIS Services, 440 Baldwin, Eddystone, PA, 800-745-9981

Purchase Cost: $3414-5114. This price is for a test unit and all accessories. The low end of the range is for ultrasonic measurement

only. The high end is for sonic and ultrasonic measurement with a data logger. An intermediate model that measures, but does not

record sonic and ultrasonic sounds is also available. 

Warranty: The systems are covered by a 1-year warranty.
31

FEDERAL ENERGY MANAGEMENT PROGRAM

Installation Labor/Material/Cost: There are no costs associated with installing the equipment, but users will need to be trained to

distinguish the sounds of properly functioning traps from the sounds of different failure modes. The length of training depends on

the user’s familiarity with steam trap principles, but should require no more than 2-3 hours of classroom instruction, plus a hands

on field session testing actual steam traps.

Operating Labor/Material/Cost: Mostly the time required to walk from one steam trap location to the next and record the test 

results; sound measurement is instantaneous.

Manufacturer: UE Systems, Inc.

Address: 14 Hayes Street; Elmsford, New York 10523

Phone: 914-592-1220

Fax: 914-347-2181

Contact: Terry O’Hanlon

Product Name: Ultraprobe 2000

Description: The Ultraprobe 2000 is a portable, hand-held instrument for detecting and measuring ultrasonic sounds.

Operating Mechanism: The flow of steam or condensate through a steam trap creates turbulence, which results in ultrasound. Ultrasonic frequencies between 20 and 100 kHz are detected, measured, and converted to audible frequencies between 100 Hz and 3 kHz.

By converting the ultrasonic frequencies generated by an operating steam trap into the audible range, the Ultraprobe allows users to

hear through a headphone and see on a meter sound characteristics that allow an assessment of a steam trap’s condition.

How Applied: The tip of the Ultraprobe “gun” is held on the steam trap, allowing ultrasonic frequencies to be measured and converted to audible sounds. The Ultraprobe can be tuned to any frequency within 20-100 kHz, which allows differentiation between

steam and condensate flows while reducing interference from other ultrasonic signals and ignoring frequencies outside of this range.

The user must be trained to identify and differentiate between the sounds expected from a properly functioning trap and the sounds

from a trap that has failed close, failed open, or is leaking steam.

Installation Requirements: The Ultraprobe gun and headphones are portable. No installation is required.

Application Limitations: Although the Ultraprobe can be applied to any type of trap, the sounds associated with properly working

and failed traps vary with the type of trap, so training on the different types of traps installed at the user’s facility is required. Training may take as little as 15 minutes according to UE Systems, however. In addition, the most accurate results will be achieved when

the tip of the gun can be placed in direct contact with the steam trap, which may not always be possible. Although an attachment

will allow measurement of airborne signals, it’s often difficult to distinguish the source of the signal when operating in this mode,

especially in a process plant environment where there are many signal sources.

Experience: Units sold/installed: The Ultraprobe has been sold to thousands of customers.

Federal customers: Includes the Navy, Coast Guard, NASA, Westinghouse Hanford, and several Department of Energy

National Laboratories.

Federal reference: Peter Palamidis, Preventative Maintenance Coordinator at Brookhaven National Laboratory, uses the

Ultraprobe 2000 to survey the approximately 2,500 traps at their facility. He says that the Ultraprobe is a “good system,”

and was especially enthusiastic about the support that UE provides to their customers. Formal training is accomplished

with a short video, but Peter feels that a day in the field is required to become comfortable with use of the device.

Peter Palamidis, Preventive Maintenance Coordinator, Brookhaven National Laboratory, Building 097, Upton, New

York 11973, 516-344-2462 

Purchase Cost: Ranges from $3500 to $4900, depending on the specific accessories ordered. 

Warranty: The Ultraprobe is covered by a 5-year warranty.

Installation Labor/Material/Cost: There are no costs associated with installing the equipment, but users will need to be trained to

distinguish the sounds of properly functioning traps from the sounds of different failure modes. The length of training depends on

the user’s familiarity with steam trap principles, but should require no more than 2-3 hours of classroom instruction, plus a hands

on field session testing actual steam traps.

Operating Labor/Material/Cost: Mostly the time required to walk from one steam trap location to the next and record the test 

results; sound measurement is instantaneous.
32

FEDERAL ENERGY MANAGEMENT PROGRAM

Appendix B

Federal Life-Cycle Costing Procedures and the BLCC Software

Federal agencies are required to evaluate energy-related investments on the basis of minimum life-cycle costs (10 CFR Part 436). A

life-cycle cost evaluation computes the total long-run costs of a number of potential actions, and selects the action that minimizes

the long-run costs. When considering retrofits, sticking with the existing equipment is one potential action, often called the baseline

condition. The life-cycle cost (LCC) of a potential investment is the present value of all of the costs associated with the investment

over time. 

The first step in calculating the LCC is the identification of the costs. Installed Cost includes cost of materials purchased and the labor

required to install them (for example, the price of an energy-efficient lighting fixture, plus cost of labor to install it). Energy Cost

includes annual expenditures on energy to operate equipment. (For example, a lighting fixture that draws 100 watts and operates

2,000 hours annually requires 200,000 watt-hours (200 kWh) annually. At an electricity price of $0.10 per kWh, this fixture has

an annual energy cost of $20.) Nonfuel Operations and Maintenance includes annual expenditures on parts and activities required to

operate equipment (for example, replacing burned out light bulbs). Replacement Costs include expenditures to replace equipment

upon failure (for example, replacing an oil furnace when it is no longer usable).

Because LCC includes the cost of money, periodic and aperiodic maintenance (O&M) and equipment replacement costs, energy 

escalation rates, and salvage value, it is usually expressed as a present value, which is evaluated by 

LCC = PV(IC) + PV(EC) + PV(OM) + PV(REP)

where PV(x) denotes “present value of cost stream x,”

IC is the installed cost,

EC is the annual energy cost,

OM is the annual nonenergy O&M cost, and

REP is the future replacement cost.

Net present value (NPV) is the difference between the LCCs of two investment alternatives, e.g., the LCC of an energy-saving or

energy-cost-reducing alternative and the LCC of the existing, or baseline, equipment. If the alternative’s LCC is less than the baseline’s

LCC, the alternative is said to have a positive NPV, i.e., it is cost-effective. NPV is thus given by

NPV = PV(EC0) – PV(EC1)) + PV(OM0) – PV(OM1)) + PV(REP0) – PV(REP1)) – PV(IC)

or

NPV = PV(ECS) + PV(OMS) + PV(REPS) – PV(IC)

where subscript 0 denotes the existing or baseline condition,

subscript 1 denotes the energy cost saving measure,

IC is the installation cost of the alternative (note that the IC of the baseline is assumed zero),

ECS is the annual energy cost savings,

OMS is the annual nonenergy O&M savings, and

REPS is the future replacement savings.

Levelized energy cost (LEC) is the break-even energy price (blended) at which a conservation, efficiency, renewable, or fuel-switching

measure becomes cost-effective (NPV >= 0). Thus, a project’s LEC is given by

PV(LEC*EUS) = PV(OMS) + PV(REPS) – PV(IC)

where EUS is the annual energy use savings (energy units/yr). Savings-to-investment ratio (SIR) is the total (PV) savings of a measure divided by its installation cost:

SIR = (PV(ECS) + PV(OMS) + PV(REPS))/PV(IC).

Some of the tedious effort of life-cycle cost calculations can be avoided by using the Building Life-Cycle Cost software, BLCC, developed by NIST. For copies of BLCC, call the FEMP Help Desk at (800) 363-3732.
FEDERAL ENERGY MANAGEMENT PROGRAM

About the Federal Technology Alerts

The Energy Policy Act of 1992, and subsequent Executive Orders, mandate that

energy consumption in the Federal sector be reduced by 35% from 1985 levels

by the year 2010. To achieve this goal,

the U.S. Department of Energy’s Federal

Energy Management Program (FEMP)

is sponsoring a series of programs to

reduce energy consumption at Federal

installations nationwide. One of these

programs, the New Technology Demonstration Program (NTDP), is tasked to

accelerate the introduction of energyefficient and renewable technologies

into the Federal sector and to improve

the rate of technology transfer.

As part of this effort FEMP is sponsoring

a series of Federal Technology Alerts

(FTAs) that provide summary information on candidate energy-saving technologies developed and manufactured

in the United States. The technologies

featured in the FTAs have already 

entered the market and have some 

experience but are not in general use 

in the Federal sector. Based on their 

potential for energy, cost, and environmental benefits to the Federal sector,

the technologies are considered to be

leading candidates for immediate 

Federal application.

The goal of the FTAs is to improve the

rate of technology transfer of new 

energy-saving technologies within the

Federal sector and to provide the right

people in the field with accurate, up-todate information on the new technologies so that they can make educated

judgments on whether the technologies

are suitable for their Federal sites.

Because the FTAs are cost-effective 

and timely to produce (compared with

awaiting the results of field demonstrations), they meet the short-term need of

disseminating information to a target

audience in a timeframe that allows the

rapid deployment of the technologies—

and ultimately the saving of energy in

the Federal sector.

The information in the FTAs typically

includes a description of the candidate

technology; the results of its screening

tests; a description of its performance,

applications and field experience to

date; a list of potential suppliers; and

important contact information. Attached 

appendixes provide supplemental information and example worksheets on the

technology.

FEMP sponsors publication of the FTAs

to facilitate information-sharing between

manufacturers and government staff.

While the technology featured promises

significant Federal-sector savings, the

Technology Alerts do not constitute

FEMP’s endorsement of a particular

product, as FEMP has not independently verified performance data provided by manufacturers. Nor do the

FTAs attempt to chart market activity

vis-a-vis the technology featured. Readers should note the publication date on

the back cover, and consider the FTAs

as an accurate picture of the technology

and its performance at the time of publication. Product innovations and the 

entrance of new manufacturers or suppliers should be anticipated since the

date of publication. FEMP encourages

interested Federal energy and facility

managers to contact the manufacturers

and other Federal sites directly, and to

use the worksheets in the FTAs to aid

in their purchasing decisions.

Federal Energy Management Program

The Federal Government is the largest energy consumer in the nation. Annually, in its 500,000 buildings and 8,000 locations worldwide, it uses nearly two quadrillion Btu (quads) of energy, costing over $8 billion. This represents 2.5% of all 

primary energy consumption in the United States. The Federal Energy Management Program was established in 1974 to 

provide direction, guidance, and assistance to Federal agencies in planning and implementing energy management programs that will improve the energy efficiency and fuel flexibility of the Federal infrastructure.

Over the years several Federal laws and Executive Orders have shaped FEMP's mission. These include the Energy Policy

and Conservation Act of 1975; the National Energy Conservation and Policy Act of 1978; the Federal Energy Management

Improvement Act of 1988; and, most recently, Executive Order 12759 in 1991, the National Energy Policy Act of 1992

(EPACT), Executive Order 12902 in 1994, and Executive Order 13123 in 1999.

FEMP is currently involved in a wide range of energy-assessment activities, including conducting New Technology 

Demonstrations, to hasten the penetration of energy-efficient technologies into the Federal marketplace.

This report was sponsored by the United States Government. Neither the United States nor any agency or contractor thereof,

nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for 

the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that 

its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by

trade name, mark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or

favoring by the United States Government or any agency or contractor thereof. The views and opinions of authors expressed

herein do not necessarily state or reflect those of the United States Government or any agency or contractor thereof.
FEDERAL ENERGY MANAGEMENT PROGRAM

For More Information

FEMP Help Desk

(800) 363-3732

International callers please use 

(703) 287-8391

Web site: www.eren.doe.gov/femp

General Contacts

Ted Collins

New Technology Demonstration 

Program Manager

Federal Energy Management 

Program

U.S. Department of Energy

1000 Independence Ave., SW, EE-92

Washington, D.C. 20585

Phone: (202) 586-8017 

Fax: (202) 586-3000 

theodore.collins@ee.doe.gov

Steven A. Parker

Pacific Northwest National 

Laboratory

P.O. Box 999, MSIN: K5-08 

Richland, WA 99352

Phone: (509) 375-6366

Fax: (509) 375-3614

steven.parker@pnl.gov

Technical Contact

Daryl Brown

Pacific Northwest National 

Laboratory

P.O. Box 999, MSIN: K8-07 

Richland, WA 99352

Phone: (509) 372-4366

Fax: (509) 372-4370

daryl.brown@pnl.gov

Produced for the U.S. Department

of Energy by the Pacific Northwest

National Laboratory

DOE/EE-0193

July 1999

Printed with a renewable-source ink on paper containing at least 50% wastepaper, including 20% post consumer waste