Booster compressor guide: types, applications & selection

A booster compressor, also called an air or gas booster, raises the pressure of already compressed air or industrial gas. Installed downstream of a primary compressor, it delivers higher pressure where needed, for example 25 to 40 bar or around 300 bar, without increasing pressure across the whole plant. This guide covers how boosters work, the main types (air, gas and oxygen), typical applications, and key selection factors.

How booster compressors work

A booster compressor increases pressure by compressing a gas that is already above atmospheric pressure. In practice, a primary compressor supplies compressed air or gas to the booster inlet. The booster then raises that inlet pressure to the required outlet pressure, usually using piston-based compression designed for higher pressure duty.

A simple process flow looks like this:

Primary compression: Ambient air is compressed by a standard compressor to a typical plant pressure, often up to about 13 bar.
Booster inlet: The booster receives this compressed air or gas as its feed.
Pressure amplification: The booster compresses the inlet gas further. Depending on the model, this can be a single-stage or multi-stage process.
Cooling and conditioning: Higher pressure ratios create more heat. Many booster systems use intercooling or aftercooling to manage discharge temperature and protect downstream equipment.
High-pressure outlet: The gas is delivered at the pressure needed by the point-of-use process.

Because the booster starts from an elevated inlet pressure, the overall pressure ratio can be achieved efficiently. For example, an inlet supply near 13 bar can be boosted to 40 bar for medium-pressure applications, or to 200 to 350 bar for high-pressure use, and some specialised systems can reach up to 1000 bar.

The principle of pressure amplification

In a typical two-stage system, the primary compressor supplies air at a baseline pressure (e.g., 7 bar) to the booster's inlet. Because the air is already dense, the booster performs less work to reach the target discharge pressure compared to a machine starting from atmospheric conditions. The relationship between inlet and discharge pressure is defined as the pressure ratio. The work required for compression follows the polytropic process equation:

By increasing the initial inlet pressure (P1), the total work (W) needed to achieve the final pressure (P2) is significantly reduced.

Types of booster compressors

Booster compressors can be grouped by the gas being compressed and the pressure band required.

Air booster compressors

These are used when the compressed medium is standard compressed air. Common medium-pressure applications operate around 20 to 40 bar, for example PET bottle blowing, industrial cleaning, and some forms of stress or pressure testing. For stable demand at these pressures, a booster can act as a produce-as-needed solution at the point of use.

Gas booster compressors

Gas boosters are designed to handle industrial gases such as nitrogen, CO₂, or other process gases, where materials compatibility, sealing, and cleanliness requirements may differ from standard air systems. They are used in gas handling processes, pressure testing with specific gases, and applications where the process medium is not air.

Gas booster compressors

Oxygen boosting requires particular attention to cleanliness and safety because oxygen can increase ignition risk in the presence of contaminants. Oxygen boosters are commonly used in medical oxygen supply systems and industrial oxygen applications where higher delivery pressure is required. In these applications, oil-free technology and rigorous cleanliness practices are typically expected.

Pressure classifications as a practical selection lens

Medium pressure is often considered about 20 to 40 bar, while common high-pressure ranges are about 200 to 350 bar, with some specialised processes requiring even higher pressure. A frequent practical split is around “40 bar” and “300 bar” classes, depending on whether the process is continuous medium-pressure use, high-pressure cylinder filling, or inherently high-pressure processes such as laser cutting and certain forms of pressure testing.

Industrial applications and benefits

Boosters are used when one process needs higher pressure than the rest of the plant.

Manufacturing and production

PET bottle blowing often needs medium pressure, commonly around 40 bar.
Laser cutting and some plastics forming processes can require high pressure.
Industrial cleaning and pressure testing are also common booster use cases.

Oil and gas and energy-related work

Pressure testing of components and lines is a frequent high-pressure requirement.
Gas handling steps may require boosting a specific process gas rather than raising overall plant pressure.

Medical and industrial oxygen systems

Oxygen supply or distribution systems may require higher delivery pressure, with strict quality and cleanliness expectations.

Key benefits of a booster approach

Targeted high pressure: Only the application that needs high pressure is boosted, instead of increasing pressure across the whole plant.
System flexibility: A primary compressor can still serve normal pneumatic demand while the booster supports a specialised process.
Efficiency advantages in many layouts: Starting from already compressed air means the booster operates over a smaller pressure lift than a high-pressure compressor starting from ambient conditions.

Air quality note: where the process is sensitive, specify the required air purity class per ISO 8573-1 and align filtration and compression technology accordingly, especially for oil-sensitive applications.

There are a few ways you can achieve compressed air or gas with a higher pressure. These include increasing the pressure of your entire plant, or working with an amplifier or stand-alone high-pressure compressor. Why is a compressor/booster combination the preferred solution? Because it is more energy- and thus cost-efficient. By using already compressed air, the difference between inlet and outlet pressure is smaller than when starting from ambient air. This results in better performance and energy efficiency. A compressor and booster also offer more flexibility. Different pressure booster models are available so you can find the ideal fit for your application. In addition, the standard compressor can also be used for other on-site pneumatic applications.