A Guide to Air Compressors

Introduction

Compressed air is often referred to as the ‘fourth utility,’ as it’s as essential to industrial operations as water, gas and electricity. At the heart of every compressed air system lies the air compressor – a piece of equipment that transforms power into pressurised air to drive essential applications.

Whether it’s ensuring precise control in refinery instrumentation, maintaining product purity in pharmaceutical manufacturing, or providing clean air for offshore maintenance, air compressors play a vital role in supporting continuous, reliable and compliant operations.

Today’s industrial landscape demands more than performance alone. With stricter environmental regulations and increasing pressure to reduce energy consumption, organisations are turning to oil-free and energy-efficient air compressor technologies to meet operational and sustainability goals.

As industries evolve, the importance of choosing the right air compression system becomes about safeguarding processes, reducing risk, and contributing to a cleaner, more efficient future.

What is an Air Compressor?

An air compressor is a machine that converts power, typically from an electric motor, diesel engine, or renewable-assisted sources, into potential energy stored as compressed air. This compressed air can then be released and used to power equipment, automate processes and maintain safe and efficient operations across a wide range of industrial environments.

In its simplest form, an air compressor draws in atmospheric air, compresses it to a higher pressure, and delivers it as a steady, reliable energy source. In industrial settings, this energy is indispensable. It powers pneumatic tools and actuators, controls valves and instrumentation systems, supports material conveying, and enables automated manufacturing processes.

Compressed air also plays a role in cleaning, cooling, drying, and maintaining controlled environments, particularly in sectors where air purity and consistency are vital to product quality and safety.

For industries such as petrochemical, pharmaceuticals, food and beverage, utilities, and offshore energy, compressed air helps build a foundation for reliability, compliance and efficiency. By ensuring a continuous and clean supply of pressurised air, modern compressor systems help plants maintain uptime, reduce contamination risks, and meet stringent international standards for air quality and environmental performance.

How Do Industrial Air Compressors Work?

At its core, an air compressor operates through a simple three-stage process: intake, compression and discharge.

Intake: During the intake phase, the compressor draws in ambient air through a filter, removing dust and particles.
Compression: In the compression stage, this air is pressurised within a chamber using mechanical force generated by pistons, screws or other rotating elements. The compressed air’s volume decreases while its pressure (and therefore potential energy) increases.
Discharge: Finally, during discharge, this pressurised air is stored in a receiver tank or directed straight into the system where it powers tools, instrumentation or other industrial processes.

Visit our Product Explorer and select ‘Oil-Free Air Compressors’ to explore Aggreko’s diesel/HVC or electric compressors.

Types of Air Compressors

There are two main types of industrial compressors:

Oil-lubricated: these models use oil to cool and seal internal components during operation, but this introduces the risk of oil vapour or residue entering the air system.
Technically oil-free: Class 1 air is achieved by using oil-flooded air compressors with filtration to capture some of the oil passing downstream.
Oil-free: compressors engineered to deliver ISO 8573-1 Class 0 certified air, eliminating any chance of oil contamination. Instead of oil, they use advanced coatings, high-performance materials and precision engineering to reduce friction and heat.

Oil-free compressors ensure a clean, reliable and contamination-free air supply. This is essential for sectors such as petrochemical, pharmaceutical and food production, where even trace contamination can compromise safety, product integrity or environmental compliance.

Many modern electrically powered compressors incorporate variable speed drive (VSD) technology, which automatically adjusts motor speed to match air demand. This reduces unnecessary energy use, lowers operating costs, and minimises wear and tear. Additionally, Stage V-certified diesel compressors, which comply with the strictest emissions standards, reduce NOx, particulate matter and CO₂ output. These advancements keep critical industries operating safely, sustainably and without interruption.

Why Purity Matters

In industrial environments where precision, safety and compliance are vital, oil-free air compressors deliver clean, contamination-free air without using oil in the compression chamber. Instead of relying on oil for sealing and lubrication, oil-free systems use specialised materials and advanced coatings that minimise friction and wear, maintaining efficiency while ensuring the air remains pure.

This design eliminates the risk of oil contamination, which can otherwise compromise sensitive production processes, damage equipment, or lead to costly product recalls. By removing oil from the equation, operators benefit from lower maintenance requirements, reduced downtime, and greater operational reliability.

100% oil-free compressors are also fully compliant with ISO 8573-1 Class 0, the strictest international standard for air purity.

Beyond operational benefits, oil-free technology also supports the growing commitment to sustainability. Without the need for oil filtration, disposal or condensate management, these systems reduce environmental impact and waste handling requirements.

For sectors such as petrochemical, pharmaceutical and food production – where microscopic contamination can halt operations – oil-free air compressors are a necessity. They deliver the cleanest air for the purest processes, safeguarding operational integrity and environmental responsibility.

What Are Industrial Air Compressors Used For?

Across the industrial landscape, uses for air compressors depend on the specific needs of each sector, but their purpose is always the same: to provide reliable, efficient and contamination-free air that keeps operations running safely and smoothly.

Petrochemical & Refining

In the petrochemical sector, where safety, precision and purity are non-negotiable, air compressors are vital. They:

Supply instrument air to operate valves and pneumatic controls with precision
Support catalyst regeneration by removing coke deposits
Aid in air separation for nitrogen and oxygen production

They’re also used in VOC removal from wastewater, stripping hydrocarbons, and maintaining pressure during turnarounds or planned maintenance. In these high-risk environments, ISO 8573-1 oil-free air is critical to prevent contamination and ensure compliance with environmental and safety standards.

Manufacturing

In manufacturing, compressed air drives productivity and automation. Within the sector, applications vary across industries:

Automotive: air compressors power pneumatic tools for vehicle assembly, robotic systems for automation, and spray-painting operations that demand clean, oil-free air to achieve flawless finishes. They’re also used in lamination, windshield testing and pneumatic conveying systems to transport materials efficiently.
Pulp and paper: compressors support air bearings and castors for handling heavy rolls, roller adjustment to maintain uniform sheet thickness, and drying and cooling of paper during production. Low-pressure air also drives air knives to remove moisture and debris and supports surface treatment and printing equipment operations.
Pharmaceuticals: oil-free compressors supply instrument air for process control, cleaning and drying for packaging lines, and low-pressure air for wastewater treatment within production facilities. Their ability to provide sterile, moisture-free air helps maintain compliance with strict GMP standards.
Food and beverage: compressed air plays a key role in fermentation, transporting ingredients and cooling baked goods. It’s also used for bottle cleaning, mould cleaning and packaging, ensuring no contamination reaches consumable products. Oil-free systems are essential for maintaining hygiene and product quality across food and beverage production lines.

Oil & Gas

In the oil and gas industry, compressed air is critical for both onshore and offshore operations. It’s used for:

Pipeline drying and purging to remove moisture and contaminants
Instrument air to control valves and pneumatic systems

Its reliability under demanding conditions ensures safe and uninterrupted operations.

Utilities

Power generation and utility facilities depend on compressed air for instrumentation, soot blowing and aeration in water treatment systems. It’s also used for nitrogen generation and pipeline pressure testing, helping maintain process integrity and efficiency across power stations and industrial sites.

Offshore & Shipping

For offshore wind, oil and marine environments, air compressors deliver essential support for bubble curtains, which are protective barriers used to reduce underwater noise and safeguard marine life during drilling or construction. They also power pneumatic tools and support painting and surface treatment tasks on vessels and offshore platforms.

Construction

In the construction industry, air compressors are used for a wide variety of demanding applications. They provide power for sandblasting, painting and spraying, ensuring high-quality surface finishes on infrastructure and equipment.

Compressed air also supports pipeline pressure testing, driving drilling and tunnelling equipment, and drying systems, which are essential for maintaining safety and efficiency on-site.

When Stage V diesel or electric oil-free compressors are used, they deliver the necessary performance with reduced emissions, noise and downtime.

Are Industrial Air Compressors Loud?

While traditional compressors were known for high noise levels, modern systems, particularly electric and oil-free designs, have been engineered to operate far more quietly and efficiently.

Typical industrial compressors produce between 74 and 84 decibels (dBA), depending on the model and power source. Electric VSD compressors, for example, operate at around 74 dBA, which is comparable to the sound of normal conversation and well within acceptable limits for most industrial environments.

In contrast, Stage V diesel-driven compressors produce slightly higher levels, around 84 dBA, due to their engine-driven operation.

To further minimise disruption, many units are designed with acoustic enclosures and housings that absorb sound and reduce vibration. These features make them ideal for noise-sensitive areas, such as urban manufacturing facilities, pharmaceutical plants or offshore environments where personnel work in close proximity to machinery.

Noise control is also a safety and productivity consideration. Prolonged exposure to excessive sound can affect concentration, communication and hearing health. By using low-noise, oil-free and acoustically enclosed compressors, operators can create safer working conditions, maintain compliance with workplace noise regulations, and improve overall site efficiency.

Sustainability and Efficiency

Industrial operations are under growing pressure to reduce emissions, optimise energy use, and meet increasingly stringent environmental targets – all without compromising on productivity. To support this shift, Aggreko has developed its Greener Upgrades initiative: a programme dedicated to delivering low-emission, high-efficiency power and temperature control solutions that help industries transition to cleaner, more sustainable operations.

At the heart of this commitment are innovations in compressor technology designed to minimise environmental impact while maximising performance and reliability.

HVO-Compatible Stage V Diesel Models

Aggreko’s Stage V diesel-driven oil-free air compressors combine fuel efficiency with ultra-low emissions. These units meet the most stringent EU standards, significantly reducing NOx, CO₂ and particulate matter. They are compatible with hydrotreated vegetable oil (HVO) – a renewable, biodegradable fuel that can cut greenhouse gas emissions by up to 90%. This makes them ideal for remote or off-grid sites where electric infrastructure is limited.

Electric Variable Speed Drive (VSD) Compressors

For facilities with grid access, Aggreko’s electric VSD compressors (800 cfm and 1600 cfm) offer zero local emissions and exceptional energy efficiency. The variable speed drive automatically adjusts motor speed to match air demand, reducing unnecessary energy consumption and extending equipment life.

Aggreko Remote Monitoring (ARM)

With Aggreko Remote Monitoring (ARM) technology, performance optimisation becomes proactive. ARM continuously tracks compressor data, including operating pressure, temperature and energy use, to identify trends, predict maintenance needs, and optimise energy consumption. This ensures maximum uptime, lower fuel costs, and reduced carbon output.

Load-on-Demand and Rightsizing

Through advanced system design, Aggreko also applies load-on-demand and rightsizing techniques to ensure compressors only produce the air required at any given time. This dynamic approach eliminates wasted energy, prevents overproduction, and delivers measurable reductions in emissions and fuel consumption.

These innovations enable industries to lower their carbon footprint while maintaining operational productivity. By integrating energy-efficient, oil-free air compressors into everyday operations, businesses can achieve cleaner performance, greater reliability, and a future-ready approach to sustainability, proving that environmental responsibility and industrial performance can go hand in hand.

Choosing the Right Air Compressor

Selecting the right air compressor depends on a combination of technical requirements, operational conditions and sustainability objectives:

Every application has unique flow and pressure demands. From high-capacity process air in petrochemical plants to precision-controlled air in pharmaceutical packaging, correctly sizing the compressor ensures stable performance without unnecessary energy consumption.

For industries where contamination cannot be tolerated, such as food and beverage, pharmaceuticals and petrochemicals, ISO 8573-1 Class 0 oil-free air compressors are essential. They provide pure air to protect products and equipment and comply with regulatory standards.

The choice between electric and diesel-driven compressors depends on site infrastructure. Electric VSD units deliver zero on-site emissions and lower running costs, while Stage V diesel models are ideal for remote or mobile applications where grid power is unavailable.

Factors such as temperature, humidity and ambient air quality can influence performance. Industrial-grade, containerised compressors with high ambient operation and integrated cooling systems ensure dependable results in harsh or changeable environments.

For sites with strict noise limits, such as urban facilities, offshore platforms or pharmaceutical plants, models equipped with acoustic enclosures offer quiet, compliant operation without sacrificing performance.

Beyond permanent installations, temporary and scalable air compression solutions can provide critical flexibility during turnarounds, maintenance periods or unexpected breakdowns. Aggreko’s mobile units can be deployed rapidly to maintain uptime and keep essential processes running while minimising capital expenditure and operational risk.

Partnering with a provider that understands the specific challenges of your sector ensures you receive a complete solution that’s tailored, compliant and performance optimised. Backed by sector-specific expertise, engineering support and 24/7 remote monitoring, Aggreko’s approach ensures your compressed air system meets both today’s operational demands and tomorrow’s sustainability goals.

Are Oil-Free Compressors More Expensive to Run?

While oil-free air compressors typically have a higher initial purchase or hire cost than oil-lubricated models, they are not necessarily more expensive to run, and in many industrial applications, they can reduce total operating costs over time.

The higher upfront investment reflects the advanced engineering required to deliver ISO 8573-1 Class 0 certified air, guaranteeing zero oil contamination. However, when you look beyond the purchase price, the operational and lifecycle advantages of oil-free technology often outweigh the initial cost difference.

Here’s why:

Lower maintenance requirements: oil-free compressors eliminate the need for oil changes, filters and disposal management, which significantly reduces maintenance time and costs. There’s also less wear on components, resulting in fewer breakdowns and longer service intervals.
Reduced downtime and product loss: in sectors like pharmaceuticals, petrochemicals and food and beverage, even a trace of oil contamination can lead to costly product recalls or production stoppages. Oil-free systems remove that risk entirely, protecting productivity and avoiding expensive downtime.
Energy efficiency: modern oil-free compressors, especially those with VSD technology, optimise motor performance to match demand. This minimises wasted energy and can lead to savings on electricity or fuel consumption.
Environmental and compliance benefits: by producing clean, emission-free air without oil or condensate disposal, oil-free systems help companies meet environmental standards and reduce waste-handling costs, which is an increasingly important factor for sustainability-focused operations.

Conclusion

Air compressors are the unseen backbone of modern industry, powering critical processes, ensuring operational safety and supporting the drive toward cleaner, more efficient production. From petrochemical refineries and manufacturing plants to offshore platforms and utilities, they provide the reliable, high-quality air that keeps essential systems running and processes protected.

As industries face mounting pressure to reduce emissions and improve efficiency, the importance of selecting the right air compression solution has never been greater. Oil-free and energy-efficient technologies are redefining what’s possible, delivering the same power and performance with a fraction of the environmental impact.

Now is the time for operators to proactively evaluate their air systems, identifying opportunities to enhance efficiency, reduce maintenance costs, and achieve sustainability targets. Whether you need temporary support during maintenance or a long-term upgrade to meet new regulatory demands, partnering with an experienced provider ensures reliability, compliance and peace of mind.

Talk to Aggreko today to discover how our flexible, oil-free air solutions can help you maintain productivity, minimise environmental impact and achieve cleaner, more sustainable operations.