A compressed air audit is the first step toward figuring out a baseline and then determining how to fashion a more efficient system, but many plant managers don’t know how to begin that process. Sometimes, it’s as simple as picking up the phone or surfing the Internet.
“The first step in having a compressed air audit done is finding a competent compressed air auditor,” says Ron Marshall, member of the Project Development Committee at the Compressed Air Challenge, which has a resource document to help users to decide on a service provider. “Consider having a low-cost walk-through audit done first to help determine if any major issues exist that would justify the cost of a more expensive full compressed air audit. The most attractive service providers are independent operators with significant proven experience in providing successful solutions. Ask them for a list of references and to tell you about some of their projects. Many compressed air equipment vendors also have auditing services, often provided free of charge or at low cost. If you have a good relationship with your provider this is a very good option. Some energy organizations or utilities have grants to help pay the cost of these studies; your local auditors will know about these.”
Communication at the beginning of the process is critical, says Rick Stasyshan, technical consultant at the Compressed Air and Gas Institute (CAGI, www.cagi.org). “We have found it is essential that user and the auditor be in synch with the objectives of audit and understand what the possible outcomes might be, and finally that the facility understands that achieving optimum performance from their compressed air system will most likely take some paradigm shifts,” he says. “This may include modifying some current plant practices causing system inefficiencies, improving the maintenance of the system, and potentially investing in some system upgrades. While this last point sometimes causes some anxiety with the system owner, the audit results often demonstrate amazing return on investment with energy saving paybacks when implemented. It is also key to alert the entire location staff as to the purpose and intention of the compressed air audit, thus preventing data loggers from being turned off or tampered with.”
The first step is to identify specific problems and goals, explains Neil Mehltretter, system design manager at Kaeser Compressors (www.kaeser.com). “Are there specific problems that need to be addressed, or are you hoping to discover opportunities for improvement?” he asks. “Examples include fixing pressure fluctuations to improve system reliability, reducing energy costs, moisture issues, finding leaks, supply side controls, and demand side waste. If multiple managers are involved, get agreement on the priorities. Knowing what you want to do will help you select the right auditor and ensure they apply the right tools.”
Gather all information you have on your system, including the type, model, size, and age of compressors, controls, dryers, tanks, and other air system components, piping schematics, system or building drawings, if available, suggests Mehltretter. “Identify the uses of compressed air and provide a brief history of any significant air-related problems in the plant,” he offers. “Select an appropriate auditor based on your goals. Most equipment suppliers offer quick, low-cost surveys intended to open the door for sales opportunities. Many of these also offer more detailed, customer-focused audits. In both cases, these are supply-side studies. They only look at the compressed air system. Demand-side studies address the uses of the compressed air, looking for wasteful practices, but there are relatively few compressed air professionals who have the experience to evaluate plant processes, as well. Leak detection studies straddle the supply/demand line, as leaks occur all the way from the main header to points of use.
Regardless of the type and depth of the audit, expect a written report with specific findings and recommendations. Find out ahead of time what specific data they measure and what information they calculate or extrapolate. Ask to see a sample of the vendor’s final report from similar projects they’ve done to see if you will be getting the recommendations and analysis you need. Expect a thorough review of information you’ve collected and an actual walk-through of the plant to verify what’s on paper.”
The first step toward having a compressed air audit conducted at your plant is determining who you will hire to perform the audit, reminds Bob Baker, senior marketing support specialist, Atlas Copco Compressors (www.atlascopco.com). “Energy audits come in all shapes and sizes, and providers should be considered carefully,” he says. “Before hiring a company to perform a compressed air audit, ask questions. Be cautious of how the audit will be performed and by whom. Read magazine articles like this one to learn more about the audit process or visit the Compressed Air Challenge website (www.compressedairchallenge.org) to explore the many available educational resources on compressed air performance and maintenance. Find out if the company will evaluate the complete system, including both the supply and demand sides. Ask what kind of report will be provided following the audit, and find out whether or not the company offers a post audit or an annual PM check-up study. Also, ask if the company will help fix inefficiencies that are discovered during the audit. Most importantly, make sure the audit can be performed when the systems are running normally, ensuring that there is no need for any downtime.”