New standard targets energy performance

BCAS provides an update on the new ISO standard 11011 on compressed air use. The standard is in development and is due to be completed in April 2013.

Compressed air is an industrial utility that is generated on-site by the user who is responsible for its treatment and transmission to the point of use. Applications are many and varied; some are not necessarily appropriate and are a misuse of an expensive resource. Some applications waste the valuable resource as they are not optimised for best efficiency.

With the emphasis on energy management and the need to control the use of energy, that control cannot be realised until information is known about the current situation. "If you cannot measure it, you cannot improve it”, as Lord Kelvin said in 1883.

Governments wrestle with the challenge to manage precious energy resources and introduce either legislation or voluntary initiatives. In partnership with these activities the standards world has responded with Energy Management standards such as ISO 50001.

To complement that and address specific industry sectors assessment/auditing standards are being developed.

Compressed air is a substantial industrial utility that consumes upwards of 10% of industrial electrical energy. It is appropriate that the compressed air industry should with others produce an assessment standard and so it was that ISO TC118 SC6 began such a task in 2007.

Entire system considered
The new standard ISO 11011 Air compressors and compressed air systems - Energy assessment, considers the entire system, from energy inputs to the work performed and treats the compressed air systems as three functional subsystems:
·         Supply: includes the conversion of primary energy resource to compressed air energy,
·         Transmission: includes movement of compressed air energy from where it is generated to where it is used,
·         Demand: includes the total of all compressed air consumers, including productive end-use applications and various forms of compressed air waste.

It sets requirements for conducting a compressed air system assessment, analysing assessment data plus reporting and documentation of assessment findings and identifies the roles and responsibilities of those involved in the assessment.

All parties agree that an energy audit standard is needed but the process of producing such a standard has become very emotive in that not all agree how the content should be presented and indeed what that content should be.

A number of ISO member countries have done work in the energy audit field and have included compressed air systems. Some have produced simplistic approaches and others more detailed methodologies for assessment/audit.

US standards
The United States has produced the most comprehensive which was encouraged by their Department of Energy. The resulting standard was produced by ASME as EA-4 Assessment for Compressed Air Systems and had much to recommend it so following the maxim 'why re-invent the wheel…' the Secretariat of WG4 (BCAS) undertook to seek permission to use extracts from that standard. Permission was granted by ASME towards the end of 2009 to use the core principles and is acknowledged in the Introduction of the standard.

Baseline performance
Ask anyone responsible for a system how much compressed air do they use and how much does it cost to generate the answer will in most cases be a knowledgeable, 'don't know'. One of the key features of ISO 11011 will be the establishment of such facts by a process that will allow for a statement to indicate 'baseline' performance. The purpose of baselining is to establish current performance levels and costs of a compressed air system, and to correlate the results with the plant's present production levels. As improvements are made to the system, it will be possible to estimate the success by comparing the new measurements with the original baseline.

Treatment equipment
The standard also looks at optimising air treatment by assessing and validating the need for, and effectiveness of, treatment equipment as it is presently installed, also to identify opportunities for performance improvement and energy reduction.

End-use applications included
The standard considers end-use applications as part of the assessment process, some of those applications are identified as 'critical air demands' that include those end uses of compressed air that have the potential to impact product quality, production rate, scrap rate, rework cost, customer satisfaction, etc. The standard goes on to indicate that improving the performance of a critical air demand is most relevant in terms of non-energy benefits to production operations.

Maintenance considered
Placing yourself on a diet to lose weight is a good strategy but the down side is that unless you adopt a regime to maintain the benefit then the effort will be in vain. It is the case that having commissioned an assessment on your compressed air system and adopted the recommended actions the benefit needs to be maintained. The standard advocates that recommendations shall consider sustainable results related to maintenance opportunities which frequently require ongoing maintenance programs to be implemented.

ISO 11011 is not intended to replace existing compressed air assessment activities and should be seen as containing a framework for the assessment/audit process that then dovetail into the specific requirements that exist around the ISO world.