How To Avoid Microorganisms In Compressed Air

How To Avoid Microorganisms In Compressed Air

Compressed air is crucial in various industries, including the food and beverage, pharmaceuticals, and medical sectors. It’s often considered the ‘fourth utility,’ alongside water, electricity, and gas, owing to its widespread use and importance.

At Control Gear, we understand that compressed air quality isn’t just about removing physical particles like dust or oil from the air. In industries where hygiene is paramount, such as those mentioned, the potential for microbial contamination is a pressing concern.

Microorganism growth such as bacteria, viruses, and fungi, can easily find their way into compressed air coils. If not properly managed, they can cause problems, from product spoilage and decreased shelf-life in food and beverage companies, to the risk of infection in the pharmaceutical and medical sectors.

This blog will dive deep into the issue at hand, offering practical advice and showcasing the role of top-tier solutions, such as Atlas Copco products, in compressing atmospheric air safely and hygienically.

Understanding Microorganisms in Compressed Air

Types of Microorganisms

Microorganisms in compressed air systems can pose serious problems. Bacteria and mould, for example, can multiply and form biofilms, which can block filters, corrode equipment, and cause system failure. More importantly, contaminated compressed air may be unsafe for applications that require high purity standards, such as in the pharmaceutical and food industries.

Atlas Copco’s oil-free air compressors prevent the growth of these microorganisms. By providing clean, dry, and oil-free compressed air, these products can effectively reduce the risk of microbial contamination. Specifically, the Atlas Copco ZR/ZT range offers an ISO-certified 100% oil-free working environment, which is a crucial aspect in avoiding conditions favourable for microorganisms.

Conditions Favouring Microbial Growth

Microorganisms thrive under certain conditions, which, unfortunately, are often present in a compressed air system.

  • Moisture: When relative humidity levels exceed 75%, it creates a conducive environment for the growth and multiplication of microorganisms because water is an essential component of most biological processes. When a compressed air system has an inefficient drying process or inadequate maintenance, moisture can accumulate, encouraging microbial growth.
  • Suitable Temperatures: The temperature range within a compressed air system can significantly influence microbial activity. Most microorganisms, especially bacteria and fungi, prefer a moderate ambient temperature, typically between 20°C and 40°C. However, some extremophiles can survive, and even thrive, in temperatures outside this range. So, maintaining an appropriate temperature range in a compressed air system is vital to inhibit microbial growth.

To effectively mitigate these conditions favouring microbial proliferation, it’s imperative to control the humidity, temperature, and differential pressure within a compressed air system.

Contaminated Compressed Air and its Consequences

In many industries, especially food processing and packaging, compressed air is in direct or indirect contact with the product. Contaminated air can lead to spoilage, reduce product shelf-life or even cause potential consumption hazards. For instance, bacteria such as Listeria and E. coli in a compressed air system can contaminate food, causing health risks to consumers.

The risks extend beyond food contamination though. In any work environment, employees exposed to compressed air containing mould, bacteria, or other harmful airborne particles, can experience health problems. Symptoms can range from allergies and respiratory issues, to more life threatening conditions, such as Legionnaires’ disease.

How Compressed Air Can Harbour Microorganisms

The Air Compression Process

Compressed air systems used in manufacturing or industrial environments often inadvertently concentrate contaminants found in the ambient air. These contaminants may include dust and soot particles, aerosolised oil droplets, moisture, and even microbes such as bacteria, fungi, or viruses.

During the compression process, the ambient air drawn into the system can carry these contaminants. Dust and soot may originate from indoor and outdoor sources, such as machinery, human activity, or the burning of fossil fuels. Oil contamination may stem from lubricants used within the air compressor, while moisture is a common byproduct of the compression process.

Microbes, including bacteria and fungi, thrive in this environment, especially when moisture is present. Once inside the system, they can multiply and be discharged along with the compressed air.

The Influence of Moisture and Temperature

Compressed air inherently raises the temperature of the environment it interacts with. Unfortunately, the contact time during the compression process is too short to act as a sterilisation method. While heat is an effective way to kill microorganisms, it needs to be sustained over a long period to be effective. In a compressed air system, the rapid compression and subsequent cooling don’t allow for prolonged exposure to the high temperatures required to sterilise microorganisms.

Microorganisms need water to survive and proliferate. A high water vapour concentration in the air provides the perfect environment for microbial growth. By reducing the water vapour levels in compressed air, we can effectively eliminate a key factor necessary for their survival.

Atlas Copco’s desiccant dryers, for instance, can lower the dew point to an impressive -70°C, effectively removing the moisture content and helping prevent microbial contamination.

Measures to Prevent Microbial Growth

High Temperatures in Oil-free Compressors

Atlas Copco’s oil-free compressors operate at high temperatures, often exceeding 180°C, or 356°F. At these elevated temperatures, the survival and proliferation of microbes becomes exceedingly difficult. The heat effectively sterilises the air, reducing the likelihood of microbial contamination. Practical applications are in industries such as food and beverage, pharmaceutical, and electronics, where maintaining a sterile environment is crucial for quality control.

Maintaining Appropriate Moisture Levels

Maintaining appropriate moisture levels in a compressed air system is crucial in the battle against microbial contamination. Targeting a relative humidity level between 10% and 20% creates an inhospitable environment for most bacterial growth. This drier environment denies the damp conditions, which many harmful microbes need for proliferation.

Using a high-quality air dryer, like the Atlas Copco CD+ and BD+ series, can efficiently reduce both liquid and vapour water levels. They both boast a pressure dew point as low as -70°C, substantially reducing the likelihood of microbial growth.


Understanding the performance, reliability, and validation of filter elements

Choosing the right filter starts with understanding its specifications. Ensuring filters have undergone rigorous testing and validation for their performance and reliability is crucial. A reliable filter effectively reduces microorganisms and ensures the quality and safety of the compressed air.

Examining technical data sheets before selecting a filter

Data sheets provide valuable information, including efficiency, flow capacity, and pressure drop. Considering this data can help you choose the most efficient and cost-effective filter.

Choosing filters based on anticipated contamination threats

Different environments pose different contamination risks. An industrial setting might present oil-based aerosols, while a humid environment may pose water threats. It’s best to select filters that match the specific contaminant threats of your environment.

General coalescing air filters may be ineffective against microbial contaminants

Standard coalescing filters effectively remove oil and water contaminants, but may not be sufficient for microbial pollutants. However, specialised filters like Atlas Copco’s UD+ filters combine the actions of traditional coalescing filters and dry particulate filters, offering enhanced protection against microbes.

The Importance of Testing and Validation

Confirming Consistent Quality

To ensure quality control, the regular testing of any compressed air system is essential. Without consistent testing, the possibility of compromised air quality increases significantly, leading to potential contamination. Regular testing ensures that the output of a compressed air system consistently aligns with your desired air quality targets.

Compliance with Standards

In an industry where standards play a crucial role in operations, ignoring compliance is not an option. Standards like ISO 8573-1:2010 specify microorganism limits in compressed air. Regular testing validates that a compressed air system adheres to these vital industry standards, effectively reducing the risk of non-compliance penalties, and ensuring the safety and integrity of the end product.

For example, Atlas Copco’s compressed air systems meet and surpass these industry standards, offering peace of mind in both consistency and compliance. The technical specifications of the Atlas Copco ZR/ZT55-90 and ZR/ZT75-90 VSD compressors, for example, reflect this commitment to high-quality standards.

Standards and Benchmarks

Understanding the standards and benchmarks for compressed air systems is key to maintaining safety and efficiency.

ISO 8573-1:2010

The first, ISO 8573-1:2010, is an international standard that outlines specifications for the quality of compressed air used in process systems. It specifies limits for contaminants like water, oil, and particulates that can interfere with processes and harm equipment.

BS EN 12021:2014

On the other hand, BS EN 12021:2014 is a British standard relevant to breathing compressed air systems. It dictates the quality of compressed air used in respiratory protective equipment, ensuring the air is free from harmful levels of contaminants that could pose a risk to human health.

Methods To Quantify Microbial Contamination

Compressed air systems often harbour various contaminants, including microbes, that may pose significant operational risks. So, it is imperative to measure and subsequently control these contaminants.

The first step in this process involves measuring parameters such as oxygen, carbon dioxide, oil mist, and water vapour. These parameters can provide insights into the general quality of the compressed air. For instance, high carbon dioxide levels could indicate the onset of microbial activity, as many microbes produce CO2 as a metabolic byproduct. Similarly, excessive oil mist can serve as a nutrient source for microbes and foster their growth.

Another method of quantifying microbial contamination is by determining the number of colony-forming units (CFUs) per 1000 litres of compressed air. This technique, also known as microbiological air sampling, is quite effective at detecting the presence and quantity of viable microorganisms.

A practical solution to control CFU levels is using specialised compressed air equipment like Atlas Copco’s oil-free air compressors, which significantly minimise the risk of contamination.

Remember, understanding and quantifying microbial contamination are crucial steps in maintaining a safe and efficient compressed air system.

How To Avoid Microorganisms In Compressed Air
How To Avoid Microorganisms In Compressed Air

Practical Steps To Ensuring Clean Compressed Air

  1. Fixing compressed air leaks: Leaks can create a pathway for contaminants, including moisture, oil, and particulates, to enter the system and circulate throughout. Identify and promptly seal leaks to prevent the introduction of these contaminants. Atlas Copco’s ultrasonic leak detectors provide an efficient, user-friendly method for locating and rectifying leaks, ensuring cleaner, drier, and more efficient compressed air operation.
  2. Installing and maintaining air dryers: Air dryers play a crucial role in maintaining compressed air quality. Refrigerated air dryers are perfect for general applications, cooling the air to condense and remove moisture before it can enter the system. Desiccant air dryers provide an additional level of protection, delivering super-dry air that inhibits microbial growth. Atlas Copco offers a comprehensive range of reliable, high-performance air dryers with superior energy efficiency.
  3. Regular filter changes: Filters are the frontline defence against microbial growth in compressed air systems. Always use filters with the correct pore size to effectively trap particulates and ensure clean air. Regular filter changes are also critical to preventing the accumulation of microbial growth. Atlas Copco’s comprehensive range of certified filters guarantees optimal air purity and ensures your equipment’s longevity.
  4. Testing and monitoring: Regular testing and monitoring of compressed air systems can provide both peace of mind, and the early detection of emerging issues. Consistent inspections can identify potential problems before they progress to causing costly downtime, or even equipment failure. Atlas Copco’s SMARTLINK offers the real-time monitoring and analysis of any compressed air system, providing actionable insights and enabling proactive maintenance for peak system performance.

Final Thoughts on Avoiding Microorganisms in Compressed Air

Maintaining pure compressed air is critical in multiple industries, from food production to medical services, and the presence of microorganisms can lead to substantial issues in product quality, health, and overall operational efficiency.

Regular monitoring and rigorous maintenance are more than just recommended procedures, they are the preventive measures that safeguard systems against microbial contamination.

With Control Gear and Atlas Copco products, it’s easy to avoid microorganisms in compressed air and invest in the longevity and efficacy of your business operations. 

Take action now to protect your compressed air systems from microbial contamination. Control Gear offers advanced solutions tailored to your needs, ensuring optimal system performance and longevity.

Contact us today to learn more about our services, and how we can help safeguard your business. Invest in clean, microorganism-free compressed air for a secure future.