Audit Reviews

Air Power USA is the largest independent compressed air consultant organization in the world. Our specialists are recognized throughout North and South America as true authorities on all operating parameters of compressed air systems. For nearly three decades we have performed thousands of compressed air system assessments or audits with the primary objective of optimizing energy cost and improving productivity and qualify.

The articles listed are some of these assessments that have been published by prestigious industry publications. The articles are sorted by industry sector and title and offer a brief overview of the actual situation and results of the assessment. Post measurement data is also published where available.

Food & Beverage Industry


Inappropriate-Use Assessment Saves 1,881 scfm
Compressed Air Best Practices, January 2010

Brewery operation located in the Midwest spent $735,757/year in electric energy cost to operate its compressed air system. The supply side and production side assessment reduced the cost by $364,211/year (49%). Total project costs of $435,800/year which generates a simple payback period of 14.4 months. The plant was using 5,000 to 6,000 cfm with 3 to 4 centrifugal compressors on-line and appropriate blower purge dryers. The supply side efficiency was improved 25% by replacing the oldest, least efficient centrifugal with a new, more efficient, higher turndown unit and some capacity control modifications. Further direct energy reduction was accomplished by replacing the blower purge dryers with heat-of-compression type. Addressing inappropriate uses such as tagging and repair of compressed air leaks, adding auto shut offs to reduce some significant compressed air utilization (from 80% to 30%), blow off air modification, modifying of the pneumatics air booster, all accounted for 5,870,564 kWh reduction and 1,881 scfm less compressed air demand.

Food Packaging Plant

Food Packaging Factory Saves $154,000 in Annual Energy Costs
Compressed Air Best Practices, April 2012

A complete supply and demand-side audit of a California food packaging plant reduces the $386,533 annual electric operating cost by $154,372/year (31%). The $280,540 initial cost was offset by a $159,778 utility ratepayer rebate orchestrated with Air Power USA support for a simple payback of 10 months. Major compressed air reduction projects included leak identification and repair, blow-off, agitation, and cabinet cooling modifications. The supply side also required modification to enable the compressors to effectively translate less system compressed air use into a commensurate amount of lower input electric energy.

Cereal and Power Bar Facility

Food Processing System Assessment of the Month
Compressed Air Best Practices, April 2009

A cereal and power bar North American facility processes bulk food ingredients into finished packaged food products. Annual electrical energy cost to operate the compressed air system was $733,347/year. The full assessment detailed 12 projects generating an annual electrical energy savings of $214,907/year (29%) with an overall investment cost of $68,350/year (2,549,700 kWh reduction) – a simple payback of 3.8 months. The projects varied from supply side improvements improving the specific power (scfm/kW) of the air supply about 5%. Additional direct savings came from dryer operating efficiency improvements, lowering system header pressure 5 psig, and shutting off several unnecessary air compressors and dryers throughout the production area. A series of compressed air reduction projects eliminated 1,124 scfm of compressed air demand.

Prepared Food Facility

Prepared Food Plant Manages Leaks and Blow Offs
Compressed Air Best Practices, October 2010

This Midwestern prepared food facility produces prepared foods which are frozen and then shipped for distribution. The production is vertical as meals are cooked and prepared onsite. The annual electrical energy bill was $269,463 to operate the compressed air system. The assessment projects generated an annual electric savings of $112,902 (41%). The total cost for all projects $146,102 which represents a simple payback of 15.6 months. Demand side projects such as tag and repair leaks, reconfigure cabinet coolers, add Venturi flow amplifiers to open blows, replace air vibrators with electric type, remove unnecessary cooling air on motors in palletizing, and replace high pressure air used for agitations with low pressure blower supplied air, all reduced the total production air demand by 891 cfm. Modifying the compressor room piping and compressor capacity controls allowed the compressed use reduction to reduce the electric input a commensurate amount.

Food Packaging

Food Processor and Packaging System Assessment of the Month
Food Processor Saves $101,000

Compressed Air Best Practices, October 2012

This article references a facility that processes and packages food product for shipment to retail outlets. The plant annual electric energy cost was $210,000. The projects in the assessment identified $100,855 annual energy savings (48%) with an implementation cost of $100,000 for a simple payback of 12 months. A 10% improvement in the air compressor operating specific power (scfm/kW) was accomplished with appropriate piping and capacity control modifications. These same projects allowed the reduction in production compressed air use of 1,051 cfm to show result in a significant reduction of input electric energy.

Cereal Plant

North America, Chicago Cereal Plant Saves $51,981 per Year

Comprehensive study of the total compressed air system at a North America breakfast cereal and snack manufacturer saves $51,981 per year in electric energy operating costs with a $19,624 total implementation cost offset by a $15,129 utility rebate – simple payback in less than 5 months. A news release by ComEd, the Exelon Company sponsoring utility, provides details of which Air 3 Power USA performed the compressed air system review, pre-project measurement and supervised all project implementations working with site plant personnel. Verification and post-measurement were performed by a third party.

Plastic Injection Molding & Plastic Extrusion

Plastic Injection Molding Products

Plastic Injection Molder Saves $53,000
Compressed Air Best Practices, March 2012

Midwestern facility which produces plastic injection molded products of many different designs and specifications. The plants’ annual electric cost to operate the compressed air system was $94,934. The assessment identified 7 projects which generated an annual operating energy cost reduction of $53,101 (56%) with an implementation cost of $4,170 for a simple payback of about 1 month. Small but critical piping changes in the compressor room along with readjustment of the compressor capacity controls led to a specific power improvement of 20% (scfm/kW). This also allowed a 315 cfm of compressed air reduction in production air usage to result in a commensurate lower input electric energy.

Plastic Extrusion

Plastic Extruder Saves $116,000 in Energy Costs
Compressed Air Best Practices, April 2013

Plastic extrusion factory where the plant’s high-quality rotary screw compressors supplied the plant with 994 acfm of compressed air. The audit focused on the compressed air applications and reduced plant demand to 453 acfm. Forty-six leaks (worth 174 cfm) were found in the pneumatic circuits on production machinery. Eighty-four “open-blow” applications on production equipment were replaced with Venturi inducer nozzles — saving another 320 cfm. Focusing on the applications helped the customer reduce air compressor annual energy consumption by 67%! The demand side projects created $116,520/year in annual electrical energy cost with a total project implementation cost of $20,100.

Metals Processing

Steel Processing

Steel Processing Compressed Air Audit of the Month
Compressed Air Best Practices – Nov/Dec 2008

Midwest U.S. plant is one of the nation’s largest steel plants and is over 100 years old. The processes involved in the assessment were Bar Mill, Roll Mill , Hot Strip Mill, Electric Galvanizing, Slab Yard, Green Coil, Pickling, Cold Mill, Annealing, Coil Distribution and Shipping. The total annual electric cost to run the compressed air supply for this facility was $1,516,000. The identified and implemented projects generated an annual energy savings of $855,000 leaving a net electric operating cost of $660,000. Total cost of the projects fully implemented was $307,150, leaving a short payback of 4 to 5 months. There was a measured air flow reduction of 11,500 cfm which also avoided the purchase of a replacement 7,000 cfm/100 psig centrifugal. Before the assessment a 7,000 cfm/100 psig centrifugal suffered a major failure and the decision was made not to invest the money to replace it and consider upgrading the supply side equipment. After the failure of this unit, additional rentals were brought in until the replacement equipment was obtained. Plant management thought that before they upgraded the air supply to a new level, a study should be implemented to answer several questions:

    • • What are the underlying causes of this continuing increase in compressed air demand?
    • • If this is wasted compressed air with no subsequent improvement in production or quality, what is the bottom line incremental energy cost to the company?
    • • What action can be implemented to eliminate this air demand? What is the cost of the action? What is the return?

The assessment answered all these questions and the recommended compressed air reduction projects reduced the actual flow demand back to former levels eliminating the need for a replacement 1,750-hp centrifugal compressor. The most significant compressed air reduction projects were: blow off air optimization and control, air horn removals and limitation, leak identification and repair, optimizing compressed air drying, and system flow monitoring at critical points to preclude growing again.

Aluminum Mill

Aluminum Mill Reconfigures Compressed Air System
Compressed Air Best Practices – April 2010

This northwest aluminum rolling mill spends $369,000 annually in electric energy cost to operate the compressed air system. The system assessment reduced this annual electric energy cost by $120,000 (30%). The plant had grown over time and the air supply was from three separate compressor rooms (Hot Mill, Re-Melt and Cold Mill). The interconnecting piping and compressor operating profile were modified to eliminate high air velocity driven backpressure and flow resistance. This allowed the 7,000 scfm required flow to be delivered when only operating the Hot Mill room (with one less compressor) and moving the Re-Melt room and the Cold room units into permanent backup emergency use. Large heated desiccant dryers were moved into backup and an energy savings heat-of-compression dryer was mated with the oil-free centrifugal to deliver proper quality air to the Mill. This action combined with effective compressed air reduction projects led to a very successful result.

Aluminum Industry

Ohio Aluminum Industries Compressed Air System Improvement Projects Saves Energy and Improves Product Quality
US Department of Energy, Best Practice Case Study

Ohio Aluminum Industries in Cleveland, Ohio, working with the US Department of energy and its allied partner Air Power USA, Inc. implemented the projects identified in the compressed air system review. The total project yielded $73,200 in direct annual electric energy savings with a total implementation cost of $83,000.

Ohio Aluminum Industries produces a wide range of precision aluminum components for the defense, aerospace, aircraft and automotive industry. It is a vertical manufacturing process which includes green sand molding; clay sand molding and permanent and semi-permanent molding.

The main projects realigned the compressed air supply, interconnecting distribution piping configuration and process controls. The systems stability improved the very critical core machines performance.


Auto Manufacturing

Auto Manufacturer Eliminates Dryer Purge Air
Compressed Air Best Practices – Nov/Dec 2008

This northeastern U.S. automotive manufacturing facility spends $269,046/year to run the compressed air system even at a very low electric power rate of 1.9 cents/kWh (.019 kWh). The projects from this assessment reduce these energy costs by $110,166/year or 40%. The primary focus of the review was not only energy costs but reliability of the compressed air quality as well. It is mandatory that air does not exceed the -40ºF pressure dewpoint limitation. The projects accomplish this while reducing the overall compressed air demand by almost 4,000 scfm (1,000-hp). Post-measurement up to six years later have shown a constant pressure dewpoint never above -40ºF and the equipment monitoring devices in place have also shown all the savings still intact with a ±4% on projected to actual specific power.

Automotive Plant

Tier 1 Automotive Plant Saves $218,000 in Energy Costs
Compressed Air Best Practices – March 2011

A Tier 1 automotive parts plant was spending $364,259/year on electric energy to operate the compressed air system at 7.16 cents/kWh (.0716 kWh). This full system assessment (supply and production side) reduced this cost by $218,670/year or 60%. These projects also allowed the plant to have much needed backup of all its compressor rooms. Simple payback was 13 months. The plant had all their supply spread out over five different locations and ran all the compressors all the time yet “did not have enough air”. Each room entered the main distribution header at different locations making it very difficult to control or for the operating personnel to know what was actually happening. The basic work was to measure with a flow meter, kW meter and pressure transducers, and appropriate data logging equipment exactly what each unit was doing simultaneously. This data revealed which units were needed and which were not; which units were receiving false signals for control and where those signals were coming from. Continued analysis allowed the plant to make inexpensive changes to compressor and dryer alignments and reduce the overall air demand over 500 cfm and the annual operating electric energy cost over $70,000/year. Follow-up sustainability programs have continued to improve the operating efficiencies.

Food & Beverage (Cont)

Meat Processing

Meat Processing Plant Eliminates 1.000 scfm of Compressed Air flow

Compressed Air Best Practices Magazine March 2014

In this article, veteran auditor Don van Ormer describes several demand-side projects. While demand-side reduction opportunities were found on the compressed air dryers, leaks, and condensate drains the main focus is on 734 scfm of wasted compressed air used at the high- pressure blow-off locations on the meat packaging and conveying equipment.

Cornstarch Processor

Cornstarch Processor Saves $123,000 in Energy Costs
Compressed Air Best Practices Magazine March 2014

A cornstarch processor spends $553,000 per year on electricity required to run their centrifugal and rotary screw compressors. Two separate systems delivered 60-75 psig and 80-92 psig of compressed air. This required the use of all the air compressors and there were no back-up units. This system assessment story details how the plant was able to reduce the demand resulting in an annual energy savings of $123,000 and shut down air compressors that are now used as back-up air.

Beverage Bottling

Unique Piping Design Reduces Beverage Bottler’s Electric Energy Bill
Plant Services, August 2009

This west coast beverage bottling plant ran 150-hp and a 75-hp lubricant-cooled rotary screw compressors as base load with another 75-hp as a trim unit that came on as required. The annual electric operating cost was $112,507/year (1,125,078 kWh). The assessment and measurement revealed that much of this cost was from multiple units running at part load or unloaded and undetected by the operating personnel, primarily due to the copper piping size and configuration. Correcting this piping by removing the existing copper piping and replacing it with a larger, more effective configuration, using coated aluminum alloy piping system with composite reusable fitting eliminated this problem and allowed the accompanying compressed air reduction projects to generate commensurate lower input energy.

Project economics:

  • • Annual electric energy savings – $58,068
  • • Utility rebate – $41,068
  • • Cost for project implementation – $48,493
  • • Simple payback – 5.7 months

Five Compressed Air Demand Reduction Projects at the Brewery
Compressed Air Best Practices, October 2013

This brewery is a relatively large operation with nine production lines plus a keg line. Operations in the plant include palletizing, de-palletizing, filling, packaging operations, and brewing. Annual plant electric costs for compressed air production, as operating at time of assessment, was $693,141 per year at $0.06/kWh.

The total compressed air review conducted by Air Power USA covered supply side and all uses on the demand side. Average system flow was reduced to 3,111 scfm from 5,062 scfm thereby reducing the energy cost to produce the compressed air to $316,411 per year. Many projects were interrelated to create this result. This article focuses on five very specific demand side projects which are often overlooked.

Prepared Frozen Food Facility

Food Processor Reduces Compressed Air Demand
Compressed Air Best Practices, November 2011

This Midwestern prepared frozen food company spends $131,011 annually to produce compressed air for their production processes. A number of compressed air savings projects were identified which resulted in a $38,736 reduction for a total savings of 29%.

Attention was particularly paid to the packaging area using contributions such as: Venturi vacuum generators, open blow air, and compressed air leaks.

Meat Packaging Plant

Meat Packaging Plant Reduces Compressed Air Demand
Compressed Air Best Practices, March 2013

This upper Midwest meat packaging plant had a true “win-win” event. The compressed air system assessment review reduced the compressed air demand by an average 1000 cfm with three very simple and low cost projects – leak repair, converting blow air with dispersion nozzles to actual air amplifiers, and improvements in pneumatic fittings. Reliability, quality and line speed were unchanged or improved, and the implementation cost was a simple 2 month payback. This company is a corporate account of Air Power USA and the results from this audit were circulated via webinar presentation to similar plants within the family brand.


Roxane Laboratories

Roxane Laboratories Plant Expansion Requires System Assessment
Compressed Air Best Practices – May/June 2010

Roxane Laboratories, a division of Boehringer Ingelheim, faced a dilemma: how to properly configure the compressed air system for a planned plant expansion. The Air Power USA assessment delivered the results which not only made the expansion effective and possible but saved Roxane $61,000 per year in energy costs. This assessment is a great example of why to invest in a full assessment before any major changes to a compressed air system. The new air system design for Roxane not only gave them a world class system but seven years after installation it is still operating as planned and giving continuing savings. This assessment was primarily a supply side action review. The total electric energy cost to run the compressed air supply at this plant was 1,156,868 kWh or $102,453 after the supply side configuration of interconnecting piping, compressed air drying optimization, compressor capacity control optimization, and system pressure control with proper effective storage. The electric annual operating cost for the same 10 production was reduced to $42,139 generating an annual operating energy cost savings of $61,314/year. The multiplex, polyglycol, heat sink, full cycling dryers, which were oversized to handle hot summer load, were monitored and after 7 years of continuous operation were running 17% of the time and the other 19% of the time.

Pharmaceutical Plan

Three Demand-Side Projects at a Pharmaceutical Plant
Compressed Air Best Practices – February 2011

This pharmaceutical plant spends $265,100 annually on energy to operate the compressed air system at their facility. This figure will increase as electric rates are projected to be raised from their current average of 7.7 cents /kWh. The set of projects identified in the compressed air system assessment will reduce these energy costs by $139,300 per year (52%). In addition, these projects will also enhance productivity and quality. Estimated costs for completing the supply and demand-side projects total $84,350, which represents a simple payback of eight months. This review details the demand-side projects identified at this pharmaceutical plant. The projects include implementing a leak management system, installing automatic shut-off valves on equipment, and addressing inappropriate uses of compressed air (particularly blow off optimization and effective control of Venturi vacuum generators). The benefits to the facility were compressed air use reduction of 504 scfm translating into a potential energy savings of $70,056 per year included in the total $139,300 annual energy reduction.

Glass Container Manufacturing

Glass Container Manufacturer

U.S. Department of Energy (DOE) Best Practices Case Study Improved Compressed Air System Saves Energy at Glass Plant
Compressed Air Best Practices, November 2003

This article references a West coast glass container facility that produces high quality wine bottles. In 2002, the facility implemented a complete system level set of projects working with the DOE and Air Power USA which improved the compressed air system. The projects involved air system reconfiguration, air treatment capability upgrade, and pressure stabilization. The results were an operating energy cost reduction of 3.5 million kWh (verified by third party measurement) and $319,000 annual energy cost reduction. After the utility ratepayer rebate was facilitated, the net simple implementation cost payback was 3 months.

Glass Container Manufacturer

Glass Container Manufacturer
Compressed Air Best Practices – August 2011

Southwestern U.S. glass container manufacturing plant had an annual electric operating energy cost of $1,028,000. The assessment yielded projects which totaled an annual electric energy cost savings of $616,000 (49%). The total project cost of implementation was $525,000 which was offset by qualification for utility energy rebates of $425,000. After incentives, total projects had a simple payback of 2 months. The cornerstone of the energy savings program was the acquisition of two refurbished high efficiency Cooper TA upgrades: one unit to completely run the high-pressure system and the other to run the low-pressure system. This not only improved the baseline efficiency of the air system by 12%, it upgraded the reliability and expected life of the plant’s air system and provided N+1 equipment redundancy. Other key savings projects included: 1) re-piping the high-pressure system to eliminate dead heads and compressor blow off, an annual savings of $10K; 2) converting the “final blow” process from high pressure to low pressure, an annual savings of $12K; 3) removing open blows and vacuum generators and repairing air leaks, for a total reduction of 700 cfm – an annual savings of $60K. According to the plants’ senior management, two factors were key to project success: 1) having an experienced air expert on the team (like Air Power USA) that is independent and not trying to sell compressors; 2) recruiting a committed internal project leader to spearhead the project.

Glass Bottle Plant

Optimizing Centrifugal Compressors at a Glass Bottling Plant
Compressed Air Best Practices – February 2014

A large West coast US glass container manufacturing plant reduced their supply side annual electric operating cost from $3.1 million per year to $2.4 million per year. This plant utilizes 3148 scfm @ 95 psig high pressure air and 9300-9500 scfm @ 58 psig low pressure air.

The plant had (4) HP centrifugal compressors (about 2300-2400 bhp) with one unit off and two units in significant blow-off. There were also (4) LP centrifugal compressors (about 2400 bhp) all four of which were running with two units in significant blow-off. The plant also used two rental diesel engine driven units tied into the high pressure system and rated at 1200 scfm each online.

Measurement of the compressors “vital signs”, the actual demand pressure and line flow to the plant allowed the compressed air auditors to develop an appropriate compressor alignment and control strategy which also included load control repairs on some units. The net result: The rental compressors no longer needed, the HP air system running on two centrifugal units well within range of turn down and the LP air system ran on three centrifugal units.

An electric energy cost reduction with some important demand side air efficiency projects totaling $727,000/yr. None of the demand side project savings would have been possible without the realignment of the compressors and the control project.

Motor Manufacturing

Motor Assembly Plant

Motor Assembly Plant Saves $85,000 year with Compressed Air System Improvements
Office of Industrial Technologies US Department of Energy Best Practice Case Study

Bodine Electric is a manufacture of fractional horsepower electric motors in Chicago, Illinois, working the US Department of Energy and its allied partner Air Power USA, Inc. followed and implemented the projects recommended by the specific compressed air system review and created $85,000 direct annual operating electric energy savings with an implementation cost of $135,500, for a simple pay back of 1.6 years. 11
Bodine Electric’s compressed air system supports air guns, drives, computerized lathes, vertical mills, winders and soldering machines. The primary projects were improvements in the compressed air supply, distribution and air management controls.

Additional Resources

The compressed air system specialists at Air Power USA have authored published articles, given presentations or been used as sources in several prestigious industry magazines. Below is a sampling of some of these. Click any of the links below to download.

Learn more about Air Power USA’s history, our founder Hank and our 30+ years in the business.