LEAK REMEDIATION PROGRAM INTRODUCTION
Purpose of a Leak Remediation Program i
Compressed air leaks present the most obvious and often neglected opportunities to reduce energy
consumption. Oftentimes, industrial facility staff does not realize the cost and savings opportunities
associated with leaks. At times, it is not uncommon for facilities to have leakage rates in the range of 20%
to 30% of the compressed air that is generated. By being proactive in leak detection and repair, a leak
remediation program can keep facility leaks to less than 10% of total compressor(s) air flow capacity.
The following chart demonstrates how supply side air is used on the demand side for industry that does
not employ a proper compressed air management strategy:
Reducing air leaks increases the net air delivery capacity of the existing compressors. Leaks can
contribute to other operating losses, such as a drop in system pressure causing all air-operated
equipment to function less efficiently – which can adversely affect production. Leaks can shorten the life
of all system equipment, such as the compressor package itself and suggest the need to add
unnecessary compressor capacity. The compressor may have additional maintenance requirements and
increased unscheduled downtime, due to the increased running time.
This leak program can be adapted to identify and repair leaks of all types (steam, water, vacuum, product,
waste, etc.).
Training
All operators, supervisors, and maintenance personnel should be trained on how to identify leaks by ear
and sight, and how to use the leak remediation program, if applicable. All personnel who will use the
ultrasonic leak detector should be trained in its specific operation using the materials provided by the
vendor (training manual, training, video, training class, etc.). Many ultrasonic leak detectors can be tuned
to identify different types of leaks.
Compressed Air Leak Management Plan Guidelines
There are three types of air losses to be concerned about: intentional air leaks, unintentional air leaks,
and inappropriate use. In order to maintain system efficiency, all three types of air leaks must be
addressed. Intentional air leaks are leaks that have been designed into the system or are the result of
operational procedures. At times, these leaks are the result of blowing, drying, sparging, and other
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operations used in the production process. These intentional air leaks have often been installed as a
quick fix for a production problem or are used to cool production staff or equipment. Unintentional leaks
result from faulty equipment, normal wear, or damage and cause ongoing maintenance issues. They can
appear in any part of the system and require an ongoing air leak detection and repair program.
Inappropriate uses are where air is used to compensate for line design shortfalls and air is used in an
uncontrolled fashion. The following steps are critical in adopting a sustained compressed air leak
management program:
1. Designate compressed air “champions” for the supply side (compressor & dryer) and the (usage)
demand side of the compressed air system. The supply side champion should be someone who is
responsible for the compressors, supply lines, etc. The demand side champion should be a
supervisor or employee who has authority over the operational activities of that department.
2. The champions’ first task is to establish a baseline of compressed air usage. This will include actual
compressed air usage as well as leak losses. It is easiest to measure the compressed air system
during a down time – which will give the open flow rate (leaks + intentional flows, such as open
nozzles). Alternately, a measure of the system can be taken under normal conditions, and then
assume 20%-30% of that volume is due to leaks if there is not an active leak detection program.
Reference Appendix B-2 for calculations.
3. Establish a goal (quarterly, annually, etc.) for reducing compressed air usage.
4. Leaks assessment:
 During breaks, shift change, or shutdowns the compressed air system is delivering air to
supply mainly just leaks. Take advantage of this time to listen for and identify leaks, or to use
an ultrasonic leak detector according to its operating instructions. Air leaks that can be heard
often only represent about 20% of the total leaks occurring.

Survey the facility and identify the leaks:

Divide the facility into survey zones by building, area, or production line. Make sure they
are manageable portions.

Map out the survey zones on a site footprint drawing. Color coding may help with
identifying areas and survey zones. Below is an example:
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

Identify high compressed air usage areas and equipment – color code on drawing.

Identify who is responsible for compressed air use in each survey zone.

Survey each zone on a set, rotating schedule (monthly, quarterly, etc.).

Document the baseline line pressure in each survey zone. Track changes in line pressure
for each survey zone during each scheduled inspection. Report results and any variation
from baselines to those responsible for compressed air in each survey zone after each
inspection.

Listen for and identify leaks, or use an ultrasonic leak detector according to its operating
instructions.
Include the most common leakage areas in each system in the Surveys (pictures below
descriptions):

Intentional air leaks. Leaks that have been designed into the system or are the result of
operational procedures.

Inappropriate uses. Use of air and/or treatment of air systems for which the system was
not designed or intended, are often done as shortcuts to procedures.
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
Old and/or damaged equipment. Nothing lasts forever, and regular maintenance or
replacement when necessary is critical.

New fittings. Not all equipment is made perfectly at the factory. Test with ultrasonic leak
tester after each installation.

Inappropriate equipment. Various types of hose fittings are easily confused, but do not
work acceptably on all systems (i.e. accidentally using water hose fittings on compressed
air systems will lead to leaks).

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
Couplings, hoses, tubes and fittings. Tubes, barbed fittings and push-to-lock fittings are
common problems. “Octopus” junctions are also a common leak point.

Quick disconnect couplings. O-rings required to complete the seal may be missing.

Filters, regulators, and lubricators (FRLs). Low initial cost, improperly installed FRLs often
leak.

Open condensate traps. Improperly operating solenoids and dirty seals are often problem
areas.

Pipe joints. Missed welds and threaded joints are a common problem.

Control and shutoff valves. Worn packing through the stem can cause leaks.

Point-of-use devices. Old or poorly maintained tools can have internal leaks. Also
consider replacing air tools with electric or battery tools if possible.

Flanges. Missed welds are a common problem.

Cylinder rod packing. Worn packaging materials can cause leaks.

Thread sealants. Incorrect and/or improperly applied thread sealants can cause leaks.
Use the highest quality materials and apply them per the instructions.
5. Document Leaks:
 Note the leak type (air, steam, water, etc.), process line, equipment, location, size, etc. of the
leak. Alternatively, give a rating (small, medium or large) to determine priority. A template
Survey Zone Leak Inspection Log format is attached in Appendix A for this purpose.

Place a leak tag as close to the leak as possible. Insert any additional procedures for the
facility leak tag process. Leak tags should not take the place of a master leak list.
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
Submit leaks to work order system if applicable, or add leaks to a master leak list. Insert any
additional procedures for the facility work order process.

Report results and any variation from baselines to those responsible for compressed air in
each survey zone after each inspection. Also compile and track baseline to survey numbers
for each department or product line, and the entire facility. Publish trends in a visible way for
the facility after each survey.
Develop an Estimated Cost for the Air Leaks
1. See the Appendix B for information on calculating leak costs.
2. Prioritize the leak repairs:
 Establish with management a cost/benefit ratio minimum for repairing leaks on various
product lines.

Determine if repairs will require downtime. If so, evaluate the cost of the leak versus the cost
of downtime. Be sure to consider whether the production department has a planned
downtime coming up, excess capacity, stores of product, etc. which may reduce the cost of
downtime.

If downtime is needed, but cannot be obtained immediately, schedule leak repairs for planned
downtime or routine maintenance times. Be sure to track accumulated leak costs to ensure
all expenses of allowing leaks to continue are considered.

Fix the biggest leaks first to get the biggest savings. This will ensure a good start to the air
leak repair program.

Remember, leaks can grow over time, so all leaks should be repaired.
Repairs and Reductions
1. Leak repairs. Since most leaks occur at joints and connections, stopping them could be as easy as
tightening a connection or as complex as replacing faulty equipment, such as quick disconnect
couplings, fittings, pipe sections, hoses, joints, drains, and traps.
2.
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
Fix leak immediately or submit leak to work order system if applicable, or add leaks to a
master leak list to schedule repair.

If using ultrasonic detector, re-test leak after repair with detector to ensure leak is fixed.

Once the leaks have been repaired, the compressor control system should be re-evaluated to
realize the total savings potential.
3. Leak reductions. Lowering the demand air pressure so the differential across an orifice or leak lowers
the flow, reducing the system pressure, will result in a reduction of the leakage rate. Stabilizing the
system header pressure at its lowest practical range will then minimize the leakage rate for the entire
system.
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4. Document repairs:
 Associate cost savings with leak repair to demonstrate the effectiveness of the program and
the savings achieved.

Track and trend lead time to repair leaks after identification and calculate associated costs
with delaying repairs.

Document the repairs and the type of leaks to identify equipment that may have a recurring
problem. If this occurs, the process should be looked at for a root cause and a permanent
solution should be developed to stop recurring air leaks.
5. After repairs, review compressor utilization and controls protocols to determine if supply can be
trimmed back or better managed, given reduced demand.
6. Compare baselines and publish results. By comparing before and after usage, the effectiveness of
the program and the cost savings can be determined. Then, share the usage and savings results with
management and other facilities. This is very important, since the savings will solidify support for the
program.
Start Over Again
Air leaks continue to occur, so the program has to be ongoing. Surveys of each zone of all systems
should be on a rotating schedule (monthly, quarterly, etc.). Reoccurring leaks should be tracked and
evaluated for more permanent fixes (equipment changes, process changes, etc.). Review and revise leak
program annually, or whenever there is a significant problem with the compressed air system. Review this
leak program and revise to make it more effective. Use the baseline line pressures and new line
pressures from the regular surveys to inform the new procedures.
Leak Cost Calculations
1. Hole Leak Estimates:
 Note: Costs are calculated by size using an electric rate of $0.05 per kWh, assuming
constant operation and an efficient compressor.
Size
1/16”
Cost per Year
$ 523
1/8”
$2,095
1/4”
$8,382
2. System Estimates for Load & Unload Controls:
 The easiest ways to estimate the amount of leakage in the system is to start the compressor
when there are no demands on the system and bring the system to normal operating
pressure. All air-operated endues equipment should have the supply valves and/or solenoids
open to account for internal leaks. Any open blowing applications that are part of the process
should be isolated through shutoff valves. A number of measurements should be taken to
determine the average time it takes to load and unload the compressor.

The compressor will load and unload because the air leaks will require the compressor to
cycle on as the pressure drops from the air escaping through the leaks. Total leakage
(percentage) can be calculated as follows:
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Leakage (percent) =


T X 100
(T + t)
T = Time fully loaded
t = Time fully unloaded
Leakage can be expressed in terms of the percentage of compressor capacity lost. The
percentage lost to leakage should be less than 10 percent in a well-maintained system.
Poorly maintained systems can have losses as high as 20 to 40 percent of air capacity and
power.
Note: All data should be compared to the original baseline and prior readings. Many rotary
screw compressors have the capability and option to operate in load/unload control.
However, because the compressor then operates at full capacity when loaded, it is important
to check that operation at the proposed unload pressure set point will not overload the main
drive motor.
3. System estimates for other controls:
 If there is a pressure gauge downstream of the receiver, leakage can be estimated in the
system. This will require an estimate of total system volume, including any downstream
secondary air receivers, air mains, and piping (V, in cubic feet). The system is then started
and brought to the normal operating pressure (P1) and the compressor is turned off. (Note:
the facility should be in the same operating condition as # 11.).



Measurements should then be taken of the time (T) it takes for the system to drop to a lower
pressure (P2), which should be a point equal to about one-half the operating pressure.
Leakage can be calculated as follows:
Leakage (cfm free air) = V x (P1 – P2) x 1.25
T x 14.7
V is in cubic feet
P1 and P2 are in psig
T is in minutes
The 1.25 multiplier corrects leakage to normal system pressure, allowing for reduced leakage
with falling system pressure to 50 percent of the initial reading. Leakage of greater than 10
percent indicates the system likely can be improved.
Note: These tests should be carried out at least quarterly as part of a regular leak detection
and repair program.
4. Calculations for all systems:
 Below is a formula that converts several types of leak measurements into the term: “CFM or
cubic feet per minute. The formula is:
Pressure Loss X Volume in Ft3
1 Atmosphere
Time in minutes

= CFM
The formula is universal in that one can use any form of leak measurement. To use the
formula factors, refer to the chart below that explains what one atmosphere is for a particular
measurement unit. This measurement unit can be PSI, Inches of Mercury, Feet of Water or
Bars.
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Conversion Chart
1 Cubic Foot = 1728 cubic inches
1 Atmosphere = 14.7 PSI
= 29.9 inches of HG (Mercury)
= 33.9 Ft. of H2O
= 1.00 Bars

To calculate the cost of air per thousand cubic feet (MCF):
BHP x 0.746 x $/kWh
0.90
= $/MCF
CFM x 60
1000

Breakdown of formula:
kWh (to run compressor) = Brake Horse Power of Compressor x 0.746 kW/BHP
Cost of running compressor for 1 hour = kWh x $/kWh (from utility bill)
MCF/Hour = CFM of Compressor x 60
1000
$/MCF = Cost of running compressor for 1 hour
MCF/Hour
An average CFM per Break Horse Power suggested by Compressor
Manufacturers is 4.2 CFM/BHP
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5. See following tables for additional resources for calculating leak costs.
Table 1: Discharge of Air through an Orifice
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Table 2: Hole Size, Leakage, and Power Loss
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Table 3: Air Leak Cost
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This Document Adapted From
 Genie Industries – Moses Lake Hi Lift facility presentation to IEA CAC Mentored Training Dinner,
2005

Compressed Air Challenge “Best Practices for Compressed Air Systems,” 2003

Bonneville Power Administration Comprehensive Compressed Air Leak Detection Checklist, May
2006

UE Systems Compressed Air Leak Detection Guide, V 9804R

SDT North America Industrial Compressed Air Ultrasonic Leak Detection Survey Guide
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