MITIGATION OR ELIMINATION:
Managing Compressed Air
High-quality compressed air is essential to food and beverage
production. Often referred to as the fourth utility, compressed air im-
pacts many aspects of food production and processing—leaving little
room for error. A product recall could raise concerns about a company,
affecting production loss as well as consumer confidence and potentially
Due to the wide variety of applications using compressed air, incidental contact with product or
preparation surfaces is, in most cases, unavoidable. Therefore, manufacturers must be meticulous about
their manufacturing standards to ensure the utmost safety. At the same time, manufacturers must weigh
the business considerations, such as how best to maximize productivity and profitability in order to satisfy
the owners of the company and provide a return on investment.
Decisions on how best to maximize the deployment of capital and the optimization of the operational
costs will directly impact the choices made during the equipment selection phase. The interdependent
complexities make it imperative to understand tradeoffs. The food and beverage industry can be confident
in their manufacturing processes by understanding the decision-making process of selecting the
1. Assessing the Risk
• Industry Guidance by the relevant regulatory bodies
- CGMP (Current Good Manufacturing Practices)
- HACCP (Hazard Analysis & Critical Control Point)
2. Compressed Air Quality & Standards
• ISO 8573-1:2010
• Sources of Potential Contamination
• Oil, Water, Solids (viable and non-viable)
3. Processing & Packaging Applications
• Constituents of Air Demand
4. Determining the Appropriate Equipment
• Oil Injected with Synthetic Lubricant
• Oil Injected with Food-Grade Lubricant
• Oil-Free System
ASSESSING THE RISK
Food and beverage manufacturers must factor in certain risk management efforts when determining
appropriate compressed air equipment for their manufacturing requirements. Mitigating risk by following
preventative safety measures creates an environment that anticipates low-risk potential hazards, with the goal
of prevention or elimination.
The goal of all food and beverage manufacturers is to provide products to consumers that are reliably safe
and free from contaminants such as chemicals, oil, water, particulate and biological mass (e.g., mold,
fungus, virus, bacteria and prions). By creating and implementing a risk management plan that ensures
equipment is properly operated and maintained, the manufacturer safeguards against microbial
contamination of food and beverages.
“Compressed air or other gases
mechanically introduced into food or used
to clean food-contact surfaces or
equipment shall be treated in such a way
that food is not contaminated with
unlawful indirect food additives.”
—United States FDA Code of Regulations,
Title 21, Part 110.40 Subpart C item (g)
Regulatory Assurance (RA) and Quality Assurance (QA)
together with operations and design teams must develop a
risk-based approach for the application using current industry
and internal guidance for system design and operation.
Guidance from regulators is diverse concerning air quality, in
many cases, leaving it up to each individual producer to
complete their own risk assessment based on the level of
susceptibility of the product or process to contamination.
Hazard Analysis and Critical Control Points
Hazard Analysis and Critical Control Points (HACCP) is an approach to food safety recognized by the
international food and beverage community. HACCP is another preventative measure intended to remove
hazards from the production line that can potentially contaminate the end product. Similar to FSMA,
HACCP is a systematic method of preventative measures to reduce risk from external factors such as
biological, chemical or physical in order to insure product quality rather than end of line inspection. The phi-
losophy is to ensure quality through risk reduction during manufacturing as opposed to relying on inspection
as the primary method of control. HACCP controls can be utilized along the entire product value chain and
processing cycle, including preparation, production, packaging and distribution.
The United States National Advisory Committee for the Microbiological Criteria for Foods (NACMCF)
recommendations updated the seven HACCP principles to include the following:
1. Perform a Hazard Analysis
2. Decide on the Critical Control Points (CCPs)
3. Determine the Critical Limits
4. Establish Procedures to Monitor CCPs
5. Establish Corrective Actions
6. Establish Verification Procedures
7. Establish a Record Keeping System
Quality and food safety are about building quality throughout the entire process instead of at the end of the
process. Sometimes called Process Analytical Technology, the lean principles of DMAIC are employed: Define,
Measure, Analyze, Implement and Control.
COMPRESSED AIR QUALITY & STANDARDS
Once the risk-based approach is established, definition and measurement of allowable contaminants is
required. Perhaps the most widely used standard for contaminant definition and measurement is the
International Organization of Standardization (ISO) 8573 that defines classes of air purity separating con-
taminants into three categories; solids, water and oil.
International Organization for Standardization
The ISO established a new class of air quality for risk management in industries like food and beverage in
2001 with revision in 2010. The most stringent of these classes is class 0, whose limits are defined by the
user or manufacturer below class 1. In the case of oil, oil contamination can exist in liquid, aerosol and
vapor forms. Managing to Class 0 for oil by using 100% oil- free compressed air technologies helps ensure
food and beverage safety and promotes public confidence in mass-produced food and beverage products.
Sources of Potential Contamination in Compressed Air Systems
The food and beverage industries must strive to eliminate the potential for contamination in their
production lines either at the source or at the point of use. To introduce contamination is to invite risk.
Every step must protect the consumer from unhygienic products. Class 0 air would ensure end products are
free of compressor-created contaminants, but is difficult to measure and manage to such a stringent level.
“To introduce contamination is to invite risk. Every step must protect the consumer from unhygienic
When filtration is considered sterile at 2 microns, measuring and managing a program more stringent may
be unnecessary. A look at sources of potential contamination within compressed air systems, including
water, oil and solid particulates, may inform the manufacturer’s decision on the right air purity classes and
resulting equipment selection.
ISO 8573-1:2010 Air Quality Classes
Max Number of Particles Per m3
0.1-0.5 micron 0.5-1 micron 1-5 microns
Pressure Dew Point
Oil & Oil Vapor
0 As specified by the end-user or manufacturer, and more stringent than Class 1
1 ≤ 20,000 ≤ 400 ≤ 10 -100 -70 0.01
2 ≤ 400,000 ≤ 6,000 ≤ 100 -40 -40 0.1
3 - ≤ 90,000 ≤ 1,000 -4 -20 1
4 - - ≤ 10,000 37.4 3 5
5 - - ≤ 100,000 44.6 7 -
6 - - - 50 10 -
Water is a common challenge with food safety. Water exists in vapor form at the intake to the compressor
along with viable particulate. The colony forming units (CFUs) and water vapor are heated in the compression
process and cooled, forming condensed water and potentially hazardous pathogens depending on the
temperature reached in the compression process. Oil-free compressors heat the air to as much as 400°F
while oil injected compressors may reach only 180°F, allowing survival of many types of bacteria. Addition-
ally, water can enter the compressed air system directly at the point of use or through a leak path. Very dry
compressed air (below -20°F dew point) expanding to atmospheric pressure can adsorb airborne water vapor
and travel into the air stream. As water and air travel in the compressed air distribution system (piping), a low
point can collect the water and become stagnant— a breeding ground for microbial content. Therefore,
proper definition for dew point and control is important for the right air treatment equipment.
Compressed air systems that rely on oil must contend with oil in a variety of forms: liquid, vapor or aerosol.
Even oil-free compressed air systems may find oil vapor from atmospheric air to be an issue when a process
produces C6 or higher carbon chain output that is close to the intake of the compressor. For example,
manufacturers must be careful not to locate an oil-free compressor intake close to a loading dock, or the air
sample will contain elements of benzene and toluene from the diesel fumes.
The risk-based approach will help determine if an oil-free compressor is required or if a lower cost compressor
which introduces oil into the air stream then separates and filters it out is allowable. The oil is used for
lubrication, cooling and sealing media. Either way, avoiding oil contaminants promotes food and beverage
safety as well as ensures structurally sound equipment.
Dirt, bacteria, mold spores and rust are just a few of the solid particulates that can be found in compressed air
systems. Solid particulates within the production line will damage equipment and possibly the final end
product. Avoiding these contaminants can result in safe food and beverage products, reduced equipment
downtime and reduced maintenance costs. From a brand reputation, clean air promotes trust with the
PROCESSING & PACKAGING APPLICATIONS
What is the allowable level of contaminants? A look at typical food and beverage applications will help
inform the risk assessment.
The British Retail Consortium (a group of food producers in the UK) and the British Compressed Air
Society teamed up to create three categories for air applications:
1. Food or Food Surface Contact
2. Non-Contacting Food or Food Surface
3. Non-Contacting Food or Food Surface High Risk
While not an FDA- or U.S.-based guidance document, it addresses commonly held divisions for
applications. Looking deeper at the many applications of air within the industry allows categorization
according to the three uses.
FATTOM is an industry acronym that stands for Food, Acid, Temperature, Time, Oxygen and Moisture,
which are conditions that must be monitored to ensure pathogens are not allowed to develop. The
sensitivity of the product to the conditions will determine the precautions required.
Food and beverage manufacturers must consider the potential contamination risk from compressed air
when determining appropriate compressed air equipment design for their manufacturing requirements.
Mitigating or eliminating risk by following preventative safety measures creates an environment that
anticipates low-risk potential hazards, with the goal of prevention.
RISK CATEGORIES BY APPLICATION
Harvested & Assembled:
PBM Bottling Making
Food or Beverage
Slaughter: beef, pork, chicken, fish
Valves & Actuators
Pneumatic Conveying (dilute, semi, dense)
Standard Pressure Blow Molding Machine
Valves & Actuators
Rotary Labeling Machines
Packaging (pneumatic cylinders, blowing, vacuum)
CIP (Clean in Place)
CIP (Clean in Place)
Pre-Form Mold Machines
Processing (drying, sorting, assemble)
Filling or Einsing
I ( l i l )
DETERMINING THE APPROPRIATE EQUIPMENT
Because the FDA does not stipulate specific compressor types for the food and beverage industries, both
oil-free and oil-injected air compressor systems can be considered when evaluating appropriate equipment.
Each manufacturer will need to balance tradeoffs involved between impact on first costs and operational
For many food and beverage companies, an oil-free compressed air system is the only solution. Whether the
corporation has made an internal decision to completely eliminate oil from their production assembly, or
whether their buyers have made that decision for them, an oil-free compressed air solution is their only option
to eliminate risk.
Type of Compressor Rank of Cost
$ $ $ $
$ $ $
$ $ $
“Once air purity requirements are
defined through the risk assessment,
the type of equipment may be
selected or additional considerations
for equipment selection can be
However, an oil-injected air compressor system, especially when used
with food-grade lubricants, can offer some advantages, depending on
how the system will be used. In some cases, an oil-injected air
compressor system may be a component of an overall system using air
treatment to reduce contaminants introduced by the compressor. This
can be managed through a rigorous maintenance program and
continuous monitoring to ensure control is maintained.
Either way, it’s essential to consider the entire manufacturing process to determine if the product will have—or
might have—contact with compressed air at any point. Any air or gas that comes into contact with food or the
equipment used to produce it must be treated to minimize risk of contamination.
Once air purity requirements are defined through the risk assessment, the type of equipment may be selected
or additional considerations for equipment selection can be reviewed. For example, if the risk assessment de-
termines an oil-injected compressor with filtration can be used, the equipment selection owner may consider
oil-free when looking at total cost of ownership. Some side by side comparisons are below:
Three Common Compressed Air System designs for Food & Beverage applications:
Oil-Injected with Synthetic Lubricant (Oil):
• Lowest acquisition cost
• Second highest maintenance cost
• Highest risk of contamination
Initial costs of an oil-injected compressor with synthetic lubricant are less than an oil-free compressor and
present a lower hurdle to investment if capital is constrained or if the ROI needs to be of a shorter period
to meet project approval.
The tradeoff is increased maintenance and constant vigilance in system monitoring to ensure performance
parameters are kept in control.
The oil carryover is mitigated in this system design in two ways:
1. Within an oil lubricated compressor a separator element is employed to remove oil which functions as
both a lubricant and a coolant. The separator element is highly efficient removing upwards of 99.9%
of the liquid lubricant but invariably some of the oil in the form of vapor will escape further down
2. Downstream “clean up” equipment, mainly inline coalescing for 0.01 mg/m3 and carbon-based
filtration for odor removal and oil down to 0.003 mg/m3.
Therefore, attention to maintenance of the above items is critical to the risk mitigation. In addition, the
sizing of the system is of particular importance due to the fact that if the compressor spends a large
amount of time in an unloaded state, the separator performance is greatly diminished, resulting in 3–4
times the oil carryover from the unit.
• Acquisition costs are slightly higher than an oil-injected compressor with synthetic lubricant
• Highest maintenance expense
• Second highest risk expense
First costs in this type of system are still low with the tradeoff being made in increased operating costs from
maintenance and required vigilance in monitoring system performance. The oil is still mitigated as described
However, should the oil pass through the above mitigation designs, the oil is an FDA approved “Food
Grade” product that poses less risk to end product, depending on the product, of course. The downside to
this system is the fact that food-grade coolants can have a shorter life than non-food-grade coolant
requiring more frequent change-outs. Hence, this is the highest maintenance costs of the three system
Oil-Injected Food-Grade Lubricant (Oil)
• Highest acquisition cost
• Lowest maintenance cost
• Contamination risk is virtually eliminated
First costs in an oil-free system are the highest of the three with the tradeoff being made in slightly higher
power costs but with the lowest risk profile. This type of compressor has zero oil in its compression
chamber, thus the risk of oil passing downstream is virtually eliminated. In addition, the compression
process raises air temperature to about 400°F which limits viability creates a hostile environment for any
biological contaminants in the ingested air. The downside of this system is the high acquisition price, but
this system typically has a lower maintenance cost associated with it due to the elimination of oil.
Due to the nature of compressed air applications in food and beverage production, there is a risk of
incidental contact with products as well as the equipment surfaces they’re prepared on. There is little
room for error, and companies must be diligent about their manufacturing practices so that contamination
doesn’t become an issue. Following compressed air standards is one practice that can help ensure quality
and safety are not compromised. Additionally, a manufacturer needs to decide which compressed air system
works best for their particular operation: oil-injected with synthetic lubricant, oil-injected with food-grade
lubricant, or an oil-free system. By following stringent manufacturing practices with respect to compressed
air standards, manufacturers can confidently work toward the goal of contamination-free products.
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Service Sales Enablement Leader
Compression Services & Technologies, Ingersoll Rand