ISO 11011: A Step Toward Standardizing Energy Audits

ISO 11011:2013 aims to standardize the energy audit process by establishing guidelines for assessing compressed air leaks. It also addresses the competency of the assessor and the methodologies employed.

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For more than a decade, money wasted through compressed air leaks has often been cited as the number one quick fix manufacturers can take to begin getting a hold on their energy costs. Going back to 1998, a Department of Energy “Compressed Air Challenge” fact sheet notes that “leaks can be a significant source of wasted energy in an industrial compressed air system, sometimes wasting 20-30 percent of a compressor’s output. A typical plant that has not been well maintained will likely have a leak rate equal to 20 percent of total compressed air production capacity.”

Adjusting data from that 1998 Department of Energy fact sheet to 2013 dollars, a 1/4-in. leak that cost $8,382/year in 1998 would now cost a manufacturer $12,026/year. And that’s not even adjusting for the average kWh rate, which was 5 cents/kWh in 1998 and now averages about ~12 cents/kWh.

The bottom line today is the same as it was in 1998: By simply fixing compressed air leaks in your facility, the impact to your bottom is significant. The real question is: Why is this still an issue today?

One possible reason is the lack of standardization around the energy audit process in general and dealing with compressed air leaks, specifically.

In October 2013, ECOskills, an environmental training group based in the U.K., held an event to highlight the new ISO 11011:2013 standard to improve compressed air energy assessments.

Speaking at the event, Stephen Boults, capital equipment manager at Thorite (an independent U.K.-based distributor of compressed air products and process systems), explained that over 10 percent of electricity consumed by British industry is used to generate compressed air, yet many unmanaged systems waste 30-40 percent of the compressed air produced.

“Reducing current energy costs is the main driver for instigating an energy efficiency assessment,” said Boults. “Yet, up to now, virtually anybody could offer to provide energy surveys, air audits and data logging of compressed air usage, to no recognized standard, with wildly varying results and findings.”

By establishing requirements on how to conduct an energy efficiency assessment, ISO 11011 is expected to dramatically change the energy audit process. The standard addresses three aspects of compressed air systems: supply, transmission, and demand.

Boults noted that the standard also covers analysis of the assessment data, how the findings are documented, and how estimates of energy savings can be achieved. The standard also addresses the competency of the assessor as well as the assessment methodology, objectives, and scope of the audit.

“ISO 11011 enables industry to receive accurate assessments of the savings achievable by professional management of compressed air systems and the installation of energy-efficient compressors and controllers,” Boults said. “It's a win-win situation for those companies that implement ISO 11011's new energy efficiency assessments, as less electrical power consumption not only saves money but also cuts carbon emissions too.”

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