• Publication Date: 07/01/2021
  • Author(s):
    Edwards, Paul Uribe, Mauricio
  • Organization(s):
    Compressed Air Consultants
  • Article Type: Technical Articles
  • Subjects: Compressed air

Paul Edwards and Mauricio Uribe | Compressed Air Consultants

Part II of this article explained what a compressed-air system audit entails and the benefits of doing an audit. This article describes the necessary steps to implement a postaudit plan to sustain your compressed-air improvements and savings.

In PBE’s June issue, we described how to structure your compressed-air system audit to optimize financial gain. However, the audit is just one step in the overall process of optimizing your compressed-air system. Experience is often the best teacher, and we’ve seen quite a few plants miss out on savings opportunities due to poor postaudit processes. This article describes the additional steps required to realize the compressed-air system audit’s potential savings and ensure that they don’t dissipate into thin air.

The three components of a successful postaudit plan are: detailed design, project management, and sustained effort. Before discussing each of these components in detail, here are some thoughts to consider about outsourcing. The return on investment (ROI) for most compressed-air projects allows for as much of the improvement process to be outsourced as the plant desires. For instance, let’s say that a project has a 2-year ROI payback. In the world of compressed-air projects, outsourcing the detailed design and project management steps typically costs between 1 and 3 months of the total project ROI. If that’s the case, delaying work for 3 to 4 months to do the work in-house actually costs the company money, as shown in Figure 1, and the company also assumes both the performance and installation risk. With this in mind, plants that don’t have the time, inclination, or internal expertise shouldn’t hesitate to outsource any or all aspects of a compressed-air improvement project.

In this scenario, the compressed-air system improvement project cost is $500,000 with a savings of $240,000 per year. If the company outsourced this improvement work, it would cost $40,000 extra (a total of $540,000) but would speed the project up by 9 months. This trade-off means the company would begin saving money sooner than if it performed the improvements in- house, which would result in only 75 percent of the savings stream ($180,000) retained. The plant may have saved $40,000 by waiting and executing the project in-house, but waiting until it had the resources to do the project ultimately cost the company more money ($60,000 per year). Compressed air system postaudit plan.

Detailed design

Detailed design is nothing more than taking the action plan from the audit and putting it into a format that allows suppliers and contractors to bid and execute the project on time and on budget. A detailed design’s primary components are the scope of work, which details installation specifications, and the scope of supply, which details equipment specifications. For simple projects, the detailed design may be minimal, but as projects grow in complexity, the value of a detailed design becomes greater, as shown in Figure 2. While this isn’t a glamorous component of the project, it’s vital. American engineer W. Edwards Deming put it best when he said, “If you can’t describe what you’re doing as a process, you don’t know what you’re doing.”

This is an example of an electrical detailed design for a plant’s compressed-air system. This detailed design drawing created clear instructions for an automation supplier. Compressed air system postaudit plan.

The goal of the detailed design is to make the project so clear that suppliers have zero doubt as to what’s required, which ultimately makes the supplier responsible for proper execution. In one project, the detailed design was so precise that the bidder wrote, “The description of work in the ‘Electrical Scope of Work’ provided to us for bidding purposes was so detailed and in-depth that we can’t add further description to it.” That same supplier indicated that the instructions were so clear that their bid contained almost zero fudge factor (margin for error).

The detailed design also allows the project manager to have a clear understanding of what needs to be done and what needs to be managed. For example, many years ago, a confectionery plant implemented a project where the detailed design very clearly stated that the plant needed a water-cooled compressor. However, the compressor supplier that won the job decided to supply the plant with an air-cooled compressor, which ultimately increased the temperature of the operating air fed to a dryer. When the dryer didn’t work, there was all kinds of finger pointing until the root cause of the problem became clear. In this case, the supplier had to fix the problem, and it didn’t cost the confectionery plant a penny.

Project management

Project management involves anticipating any future problems that could arise when implementing a project and then planning, organizing, and executing the activities necessary to successfully complete the project. There are endless articles and books describing good project management practices, so we won’t belabor the point. Having the proper blueprint being read by somebody who understands blueprints and the activities and equipment the blueprints require is also necessary when implementing any project.

Sustained effort

Even an incredibly successful project that achieves all the desired results is incomplete if the new actions or processes aren’t maintained over the long term. Retaining the savings and achieving the projected ROI requires sustained effort by everyone involved.

For example, in 2005, we implemented a project that allowed a client to turn off six of their 12 compressors while improving air pressure stability and air quality without purchasing any new compressors. This was an impressive result. However, when we returned to the plant 3 years later, 11 of the 12 compressors were running. The client had achieved the results that the audit had recommended and that the detailed design and project management had delivered, but all these gains had since been lost. In this case, a pressure problem occurred, and the operators didn’t understand how the automation worked, so they simply cut the control wires from the automation to each of the compressors. This was a harbinger of things to come.

In 2016, we completed a series of reaudits of plants we had originally audited a decade before. We expected the majority of the plants to have fully implemented the audit recommendations and retained most of their savings over the years. After all, who wouldn’t do everything possible to retain their savings after a successful project? However, we found that one-third of the plants were actually worse off than they had been when the first audit was performed, while another third of the plants were only slightly better than when the first audit was performed. The remaining plants had maintained at least half of their savings over the decade, but only one out of the 12 plants had achieved and maintained the projected improvements from the first audit. At least that’s how it appeared on the surface.

We estimate that these reaudited plants were losing $60,000 per plant per year in savings. In addition, several of the plants had unnecessarily spent hundreds of thousands of dollars while suffering through productivity issues because they had reverted back to the original behaviors that had created the excessive costs the audit originally uncovered.

Upon further evaluation, two clear postaudit actions stood out as necessary to sustain the savings over the long term.

Faster feedback. There needs to be a faster feedback loop between system performance and key performance indicators (KPIs). As it was, some of the plants used the audits (10 years apart) as their indicator of system performance rather than doing real-time course corrections.

KPIs include the efficient use of air (measured in standard cubic feet per minute [scfm]) and the efficient production of air (measured in standard cubic feet per minute per kilowatt [scfm/kW]), as shown in Figure 3. Plant personnel should develop an understanding of how much air the system should use with various processes operating.

KPIs help operators make better decisions regarding compressed-air system settings. Compressed air system postaudit plan.

Better training. The people portion of the process needs improvement also. This breaks down into two areas: training and focus. Most plant workers know that compressed air is expensive but very few know just how expensive it is. Understanding the true costs of compressed air often helps to keep workers from using air indiscriminately. The goal is to develop a company culture where compressed air may be used as a temporary fix, but both the operators and plant management understand that it shouldn’t be a long-term fix.

You can easily and inexpensively encourage this understanding by developing a very basic training program that allows operators to understand the impact of their actions. The training should teach operators which equipment settings have the greatest impact on compressed-air costs. For example, operators often don’t understand how dust collectors work. If dusting occurs or the bag filters are blinding, operators often increase the dust collector’s pulse duration in an attempt to fix the problem, as shown in Figure 4. If they understood how a pulse-jet dust collector really works, they would know that changing the duration past a certain point would have no effect on the collector and would only waste precious compressed air. Also, new employees could go through a 10- to 15-minute web-based presentation that discusses how air is used in the plant and what the plant considers best practice for its particular processes.

At one company, operators increased the dust collector’s pulse duration (the circled dial) in an attempt to fix a problem they were experiencing with the collector. This didn’t solve their problem but created one: excessive compressed-air usage. Compressed air system postaudit plan.

Having an air champion or a compressed-air focus team that meets infrequently and for short periods of time can also pay large dividends. In one plant we just reaudited after 5 years, tens of thousands of dollars were unnecessarily spent because, after the initial audit, no one was paying attention to how individual decisions were impacting operating costs. Had there been a small focus group that met for 30 minutes on a quarterly basis to discuss all things compressed air, the plant could’ve avoided some of those costly decisions. In addition, if the plant had involved its consulting firm — whether formally or informally — the consulting firm could’ve steered the personnel in a different direction where they wouldn’t have had to spend any money.

A compressed-air focus team is more likely to have greater success than just an air champion alone, especially if the team is made up of individuals from various stakeholders within the business. Having all interested parties at the table to look at potential compressed-air decisions and their cost consequences allows a plant to make strong business decisions based on fact rather than just opinion.

Key takeaways

To conclude this three-part series on compressed-air system improvements, remember these important points:

  1. Compressed-air system improvement projects have ROIs that will often rival and surpass other projects you may have planned for system improvements, and those ROIs can often be achieved without purchasing new compressors.
  2. Looking at all the potential sources of cost reduction — productivity, operating costs, and capital costs — and involving all company stakeholders is a more financially sound approach than using discretionary money to attempt to fix system-­related issues only in the compressor room. Simply adding compressed-air capacity is often only a band-aid that won’t fix the actual problem and will cost you a lot more money in the long run.
  3. Consider using an independent expert that can demonstrate working knowledge of your processes. This eliminates the inherent conflict of interest when your advisor is also a supplier.
  4. The first step in the compressed-air improvement process is the audit. A quality audit analyzes all costs and parts of the system. The audit’s output is a fully costed action plan with financial justification for that plan.
  5. The audit output shouldn’t look like an attempt to sell a compressor, control system, or whatever the supplier has to offer. Beware of automated surveys.
  6. Long-term compressed-air system improvement savings often fall short of companies’ goals because they neglect the detailed design, project management, and sustained effort that are required postaudit. Maintaining the savings requires better, faster feedback and a change in company culture.
  7. If time is money, then postponing a project because the plant doesn’t have the time, inclination, or internal expertise to implement the project is often a poor financial decision. The ROI for most compressed-air projects is strong enough that any aspect (or all of it) can be outsourced and still meet your ROI.


Part I of this article discusses reframing your facility’s compressed-air issues with a return on investment in mind to avoid unnecessary expenditures.

Part II of this of this three-part article describes what a compressed-air system audit entails and how it can help you identify issues in your system and prioritize solutions.

Paul Edwards is founder and president of Compressed Air Consultants (CAC), Charlotte, NC, which he founded as an independent audit firm 18 years ago after starting up the audit business portion of a major compressor company. He has a BS in mechanical engineering from the University of Virginia in Charlottesville and is a nationally recognized speaker in several organizations that serve the powder and bulk solids industry.

Mauricio Uribe is an auditor at CAC and has been with the auditing team for more than 5 years, mainly doing international audits. He’s the founder of CrowsNest, an independent auditing company established 18 years ago in Santiago, Chile. He has a BS in mechanical engineering and has international auditing experience.

Compressed Air Consultants • Charlotte, NC • 704-376-2600 • www.loweraircost.com

For further reading
Find more information on this topic in articles listed under “Compressed air” in our article archive.

Copyright CSC Publishing Inc.

Download PDF