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Brainstorm: Air Quality

The Food Manufacturing Brainstorm features industry experts sharing their perspectives on issues critical to the overall food industry marketplace. In this issue, we ask: What factors should manufacturers consider when choosing systems to improve air quality in their facilities?

This article originally ran in the September 2012 issue of Food Manufacturing.

The Food Manufacturing Brainstorm features industry experts sharing their perspectives on issues critical to the overall food industry marketplace. In this issue, we ask: What factors should manufacturers consider when choosing systems to improve air quality in their facilities?

**ONLINE EXCLUSIVE** Mark White, Market Development Manager, Utility Air Company, Parker Hannifin Corporation, domnick hunter Division

When selecting compressed air treatment systems for their facilities, manufacturers should consider the following:

  • Hygiene Regulations - The link between their duty of care to protect the consumer and contamination hazards in their compressed air system
  • Equipment Suppliers – Do suppliers understand Hygiene Legislation / Standards / HACCP Principles / Compressed Air Treatment
  • Validation – What 3rd party validation is available to demonstrate equipment  suitability for use in the food industry

Food Hygiene Regulations

Food hygiene regulations place a duty of care on food manufacturers to protect the consumer by using food safety management systems based upon the principles of HACCP.  In fact, many companies are now adopting the ISO22000 standard to implement HACCP.

Compressed Air Contamination

Many users are unaware of the contamination present in compressed air and its’ sources.  Contamination must be reduced or removed to acceptable levels for the compressed air to be suitable for use in food manufacturing.

Food Hygiene & HACCP

As the risks associated with compressed air contamination are not always known by the user, it is not uncommon to find that the compressed air system and its usage points are overlooked when the HACCP Hazard Analysis (Risk Analysis) is carried out.

Every point in a food manufacturing plant where compressed air is used should be classified as a CCP (Critical Control Point), so measures must be taken to reduce or remove contamination to acceptable levels.

Equipment Suppliers

Supplying compressed air treatment systems to the food industry is not the same as it is for industrial manufacturing. A supplier with specific knowledge of the food industry, related legislations, standards and HACCP principles is required.


Always select products with 3rd party validation and materials of construction suitable for the food industry.


Lane Hawkinson, Kobelco KNW Series Sales Manager, Rogers Machinery Company

Compressed air users in the food and beverage industry are becoming increasingly intolerant of contamination in their compressed air systems. Most food and beverage products come in contact with compressed air during their creation, whether during mixing, aeration, conveying, drying, packaging or filling. The purity of compressed air is critical to product quality, taste, shelf life, color and rejection rates. To ensure the highest quality products leave a facility, it is imperative to use an oil-free compressed air system. An oil-free compressor design eliminates the risk of product or system contamination due to compressor lubricant.

Companies who use oil-lubricated air compressors go to great lengths to protect product from compressor lubricant contamination at significant cost, but small amounts of lubricant can still get into their product. Some compressor manufacturers provide lubricant labeled as food grade in their air compressors. This lubricant has a short service life, is expensive, and may not have the lubricating and cooling properties required to protect gears and bearings. Incidental lubricant contact may not be harmful to humans, but who wants compressor lubricant with their breakfast?

There have been several high profile recalls of food products due to compressor lubricant in the product. A product recall is a high price to pay in dollars and reputation for any company. The low price of an oil-lubricated compressor is soon forgotten when your entire piping system or process is compromised.

Only an oil-free compressor and the appropriate type of air dryer can eliminate the risk of contaminated product, lost production, waste and damaged reputation. This peace of mind to business owners, shareholders, employees and customers cannot be measured in dollars.


Hannah Granade, President, Advantix Systems

There are several important factors that manufacturers must consider when designing or retrofitting an air filtration system for a food processing facility. While the degree of filtration for incoming air depends greatly on the type of product being manufactured, an ideal system will control the temperature, humidity, air flow and sanitization of the air in an efficient and cost-effective way.

Complete removal of contaminants: In most conventional air filtration and heating, ventilation and air conditioning (HVAC) systems, sanitization is an additional feature. Systems that do include sanitization will use an EPA and OSHA-approved biocide treatment to kill contaminants and mold spores, fungi, mildew, bacteria and algae from the air. However, this process typically does not remove the microscopic bacteria, molds and viruses once they are neutralized or disabled by the biocide. An effective air filtration will capture and remove the small microbial organisms and prevent them from returning them to the general air stream.

Eliminating humidity: An air filtration system must work hand-in-hand with the HVAC system, and the regulation of moisture is extremely important to ensure high quality products. This can be challenging because food processing often produces more moisture than exists naturally in the environment. A properly dehumidified space will prevent the growth of mold and bacteria and ensure a comfortable environment for employees.

Energy efficiency: The sources of energy use can vary widely by food processors, but air filtration and HVAC systems typically account for as much as one-third of total energy consumption in most industrial facilities. There are new technologies available such as liquid desiccant systems that filter and disinfect the air and eliminate odors using significantly less energy and without the use of drip pans, condensation points, or expensive filters to monitor and maintain. These new technologies can help manufacturers achieve substantial energy savings without having to interfere with the core processing operations of the facility.


Paul Humphreys, Vice President Communications and Branding, Atlas Copco Compressors

Compressed air plays a critical role in the manufacturing process and, in some ways, is much like a workshop floor — everything operates better and safer when things are clean and dry. That statement might sound like a bit of a stretch, but the analogy holds true. Having clean, dry air is critical to the performance of a compressed air system, as well as the safety and integrity of the end products and those who use them.

If someone is experiencing air quality issues with their compressed air system, a good place to start is with the piping system. If the interior surface of the piping system is clean and dry, it should serve as a good indicator that there is good quality air flowing through the system without any major issues. Dust or other particulate that collects in the pipe is the result of particles in the air. If the air isn’t properly filtered, or if the filter is clogged, the system will experience pressure drops and increase the potential risk of contaminating the end product. Sludge in the pipe is equally bad news and must be fixed immediately.

In addition to the problems that occur with dust in the pipe, pipes with sludge in them will corrode very quickly and leaks will greatly increase. If there is evidence of sludge it’s likely started already. Dried and filtered compressed air keeps piping clean and also helps keep energy costs down — clogged or poorly designed piping systems waste money because they make air compressors work harder than they need to.

Finally, conducting regular maintenance on the compressed air system, including filter changes can improve performance. Just as one changes the oil in his car at regularly scheduled intervals to ensure optimum performance and reliability, regularly changing the filters that serve compressed air systems will help ensure air quality and optimal performance in manufacturing.


Brian Brian McGill, Sr. Applications Engineer, Donaldson Company

An entire air compressor system should be optimized for a cost-effective solution — from the inlet to the point of use.

Compressor Room: The compressor inlet filter is designed to keep out particles greater than 5 micron in order to protect the compressor. However, smaller particles like light oils, hydrocarbons and dirt will make their way downstream.

Compressor Itself: Is it old and inefficient, allowing excess lubricant downstream? In addition to removing lubricant, a less efficient compressor may have higher temperatures at the outlet for the same pressure. This heat must be removed, posing a greater challenge to the after-cooler.

Before Drying: Compressors typically see a dew point of 180°F or higher. Cooling this air down to 100°F will condense out over 80 percent of the water. Centrifugal mechanical separation will easily remove the bulk of this liquid, followed by a coalescing filter for the remaining aerosol droplets.

Drying: A refrigerated dryer provides air with a pressure dew point of about 38°F, well below average room temperatures. However, if feed pipes go outside between buildings, or if most of the air is required to be very dry, then a desiccant dryer is required. For large flow systems where refrigerated dryers are sufficient for the majority of the air, small point-of-use desiccant dryers can be installed on branch lines, minimizing pressure drop and desiccant change-out costs.

What filters to use and where?: The majority of air may be sent to different areas — shop tools, laboratories or to process lines. It is best to use filters with the least restrictive micron rating where possible, affording sufficient filtration with a minimal pressure drop.

If you have a main line with no branching, then it is best to install a filter train as you work down to the final filter. Installing one filter at the final process’ micron rating may reduce an overall pressure drop, however it also minimizes life and requires frequent change-outs or cleaning of filter elements. Higher micron, lower differential pressure depth pre-filters will remove large particulate, leaving the final filter for polishing.