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38 / May 2021 powderbulk.com tion. The plant learned that some minor changes to its air lance use combined with a better control and shut- down strategy could solve the issue for minimal money. Conclusion Instead of making improvements through discretion- ary spending, consider making the improvements with ROI in mind while funding the work through a budget that isn't as limited as the maintenance and engineer- ing budget. In most cases, an ROI of two years can be achieved while solving productivity issues. Sometimes the job's ROI stretches out to three years, but not in the majority of instances. Also consider using an independent auditor in conjunction with your compressed-air equipment supplier. "Trust but verify" is a popular saying that you'd be wise to follow. If a compressed-air equipment supplier believes it's your sole source of advice, then there's almost a certainty that the price of any equip- ment or service will be higher. In addition, if your compressed- air problem is poorly defined, the prob- ability that your solution will be far more expensive than necessary is likely. PBE Editor's note: Part II of this article, which will be pub- lished in June's issue, will go in depth on what an air audit entails. For further reading Find more information on this topic in articles listed under "Compressed air" in the article archive on PBE's website, www.powderbulk.com. Paul Edwards (paul.edwards@loweraircost.com) is founder and president of Compressed Air Consultants (CAC), Charlotte, NC, which he founded as an indepen- dent 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 recog- nized speaker in several organizations that serve the powder and bulk solids industry. Compressed Air Consultants Charlotte, NC 704-376-2600 www.loweraircost.com independent auditor as soon as you can. Nine times out of 10, these rentals can be eliminated, which can be of massive assistance for a project's ROI. Capital cost avoidance. Avoiding capital expendi- tures means not making large, unnecessary purchases that ultimately won't help your plant's ROI. Coming across a plant that needs a new compressor or dryer due to capacity reasons is exceedingly rare. In one industry where more than 100 compressed-air system audits were done, exactly zero plants needed additional com- pressors as long as the plants controlled their existing assets more effectively and eliminated compressed- air abuse on the demand side. Of course, there are cases where machines are old, or a local utility is providing an incentive program where replacing equipment makes sense, but these circumstances are rare. In plants that have multiple air compressors, turning off 10 to 40 percent of the compressors is usually possible without negatively affecting the plant's process. Productivity issues. If you have issues with air pressure or quality, you're likely overspending on compressed-air usage or unnecessary downtime and, therefore, have a high potential for financial return on a project. Compressed air isn't some magical substance. There are rules on how to ensure adequate air pressure and quality at all your system's points of use. What's often not understood are the particular circumstances that led to these air pressure and quality issues. Deter- mining these circumstances requires instrumentation and the ability to read and interpret the data. In one plant, the facility's conveying system had to be shut down on a regular basis due to low air pressure at one of the component's seals. After examining the system, shutdown settings were determined to be too conservative. The circumstances that the shutdowns were protecting against occurred less than 3 percent of the year, yet the shutdowns themselves were occurring weekly. Part of the problem was that this particular part of the process was remote and fed by an undersized pipe. In addition, operators would occasionally operate an air lance, which could drain the air in that local sec- Instead of making improvements through discretionary spending, consider making the improvements with ROI in mind while funding the work through a budget that isn't as limited as the maintenance and engineering budget.