Industrial Utility Efficiency    

Transitioning to Oil-Free Compressed Air

In today’s manufacturing environment, companies continually look for ways to reduce operating costs, eliminate contamination risks and minimize environmental footprints. Transitioning to a cost-effective oil-free air system providing ISO 8573-1 Class 0 certified air quality is one way to achieve these objectives.

Compressed air quality is measured by the amount of solid particulates, water and oil content in one cubic foot (cu. ft.) of compressed air. Many of these contaminants are introduced from the air surrounding the installation site that is drawn into the system at the beginning of the compression process. The relative humidity, type of compressor and air treatment and filtration system can also affect air quality. Minimum air quality requirements vary by industrial application; the most stringent standards apply to manufacturers whose end products, packaging or critical instrumentation come in direct contact with compressed air.



In 2003, Ingersoll Rand began offering the industry's first true variable speed drive, oil-free compressors featuring maintenance-free hybrid permanent magnet (HPM) motors.


In 1991, the International Organization for Standardization (ISO) established air quality and testing guidelines. The ISO created five classes to categorize air purity levels that must be provided by compressed air systems. Air quality Classes 1 through 5 dictate the acceptable amount of particulates and moisture contained in 1 cu. ft. of compressed air, but do not regulate oil content.

ISO raised the bar in 2010 and added a stringent new Class 0 air quality standard that addressed oil content. ISO 8573-1:2010 states that compressed air must contain less than 0.01 milligram per cubic meter (mg/m³) of liquid oil, oil aerosol or oil vapor per cubic meter (m3) to meet Class 0 certification standards.

ISO Table
  Class 0 defines air quality for critical applications in the food and beverage, automotive, pharmaceutical, chemical and utility provider industries.

Benefits of Oil-Free Air

Many centrifugal and rotary screw compressors have the technology to supply Class 0 certified oil-free air. It is important to note that Class 0 certified oil-free is different than virtually oil-free air. Some manufacturers use contact-cooled oil-flooded systems in conjunction with a coalescing filter to improve air quality. This virtually oil-free technology cannot deliver the same results as a Class 0 certified centrifugal or rotary screw compressor. The plant manager should confirm that the compressor has received Class 0 certification from a third-party auditor to ensure 100 percent oil-free air.

  IR Gears
Ingersoll Rand oil-free rotary screw and centrifugal air compressors were vigorously tested by TUV Rheinland, a global-leader in independent testing and assessment services, and earned ISO 9573-1:2001 Class 0 certification, guaranteeing 100% oil-free air.

Further if a filter fails, virtually oil-free systems are at higher risk for product contamination and unscheduled downtime. Filters also cause pressure drops as the compressed air moves through the system, making it inherently less efficient than an oil-free compressor.

The transition to oil-free air in a production facility may seem like a sizeable investment; however, minimal maintenance requirements increase uptime and productivity, and a properly configured oil-free system lowers energy consumption while significantly increasing ROI. These cost-saving opportunities can help fund the system retrofit and should be factored into the compressor’s overall lifecycle cost.


Maintenance and Energy Savings

Regular maintenance is critical in keeping compressed air systems running reliably and efficiently. A true oil-free compressor does not have oil in the compression module which minimizes downstream filtration requirements and pressure drops, and translates directly into energy savings. This also eliminates the need to replace air filters frequently, which reduces maintenance and inventory costs.

Rotary screw illustration

The two-stage compression module features precision-machined rotors and gearing, advanced UltraCoat rotor protection, anti-friction bearings, stainless-steel air seals, and a unique oil seal design to ensure years of reliable, trouble-free operation.


  IR Oil free nirvana
The oil-free Nirvana air compressor from Ingersoll Rand features a variable speed drive to lower operating costs and increase operating efficiency.

Energy consumption can account for up to 90 percent of the total lifecycle cost of an air compressor. Oil-free air compressors coupled with variable speed drives, heat of compression (HOC) dryers and an updated compressor control system can reduce energy demands and provide optimal flex efficiency for food and beverage manufacturers. As a result, one food and beverage manufacturer that installed an Ingersoll Rand oil-free air system increased its energy savings by 34 percent and reduced emissions by more than 460 tons of CO2 per year.


Increase Sustainability

Compressed air systems can produce large amounts of condensate depending upon the relative humidity of the climate. In an oil-flooded compressor, the condensate contains lubricant contaminants that need to be disposed of according to environmental regulations. While oil-water separators exist to remove contaminants more efficiently, oil-free air compressors completely eliminate this issue. Condensate from oil-free systems is easily disposed of reducing maintenance costs and the company’s environmental footprint.


Prevent Contamination

There is a risk of oil contamination any time compressed air comes in contact with an end-product. Contaminants can harm the quality of the end-product, cause recalls and stop production at the plant. These risks can harm the company’s reputation and profits or worse — the end-user.

Class 0 certified air compressors are safer because oil is never introduced to the production area giving the plant freedom from compressor-created contaminants. Operators should test air quality and end-products frequently to ensure the system is functioning correctly. Oil-free air compressors eliminate the need for downstream testing making them a reliable solution for critical processing applications.


Proactively Move to Oil-Free Air

While there are very few government regulations regarding oil-free air, many multi-national manufacturers are voluntarily moving to oil-free systems to reduce the risk of contamination and protect vital equipment. The transition to oil-free air is critical for food and beverage, automotive, chemical, and pharmaceutical manufacturers and power utility providers.

Manufacturers considering a move to oil-free air should conduct a plant-wide system assessment to define demand patterns and supply capacity before making any major modifications. A certified air audit team can analyze the plant air compressor’s supply, demand and distribution components to determine the entire system’s efficiency and effectiveness.

During the evaluation period, an auditor visits the plant during each shift to observe how compressed air supply and demand fluctuates throughout the day. The auditor will start by checking the supply side’s air treatment equipment, filtration, dryers, coolers, drains, piping, network pressure control and storage, and automated system controls. Next, the auditor will check the average pressure range, artificial demand and potential leaks on the demand side. The auditor should also define the limitations of the compressed air system and make recommendations for managing the plant’s compressed air usage.

At the end of the investigation, the auditor will compile a report assessing the system’s overall reliability, air quality, operating costs and environmental impact. The report should include a proposed action plan and outline the projected cost and energy savings, if the entire plan is implemented.

If a system assessment determines it is beneficial for a manufacturer to transition to oil-free air, the operations manager should contact a licensed distributor to specify the best Class 0 certified compressor for the application.


To learn more about the Class 0 certified air solutions used in food and beverage applications, visit or contact Todd Stelzer, strategic account manager, Ingersoll Rand.

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