Choosing effective air compressor filters

When treating compressed air, you'll likely want to invest in air compressor filters, dryers, and separators. This article focuses on filters.

When treating compressed air, you'll likely want to invest in air compressor filters, dryers, and separators. Installing a comprehensive air treatment system is important for maintaining clean, efficient operations.

Also, while filters should never replace dryers for improving air quality, they can reduce the workload of such equipment. With this, your desired International Standard of Organization (ISO) 8573-1 Class, from 0-9, determines the right filter and drying solution.

Essentially, both filters and dryers remove particles, moisture, microorganisms, oil, and other undesired elements found within your compressor's airflow. Focusing on filters, you'll generally find two types offered, coalescing and particulate.

This article explains the differences between those types, as well as how to properly dispose of dirty air condensate.

Choosing between options for air compressor filters

Coalescing and carbon filters

Coalescing filters are best for removing oil and dust. They contain several layers to separate contaminated water vapor (moisture) from the air. In addition, they're effective in removing dry particles.

Ceccato offers two models in this category, the series G and C. They can reduce oil to 0.3 mg/m3 and 0.01 mg/m3 respectively. With this, it's worth mentioning that 0.01 mg/m3 at 1 bar(a) and 20 C (68F) is suitable for ISO Class 2 oil purity.

Like coalescing filters, the Ceccato activated carbon series V filter is effective in removing oil. It can achieve levels of 0.003 mg/m3 at 1 bar(a) and 20 C (68F) for ISO Class 1 oil purity.

Particulate air compressor filters

There are two particulate filter variations from Ceccato, series S and D. These models respectively remove particles to 1 micron and 0.01 micron at 1 bar(a) and 20 C (68F). The latter can achieve ISO Class 1 particle purity.

Filter types and placement

A typical air compressor air treatment setup includes a combination of filter types, as well as placements. As mentioned, you can place them before or after the drying system. Additionally, it's usually best to install filters before the main piping for the most efficient setup. You'll also want to pay attention to the flow rate, as that determines the correct size needed.

Class 0 air quality

If you're concerned about reaching ISO Class 0 air quality, filtration alone isn't going to help you achieve this. You'll need to invest in an oil-free air compressor. This is particularly relevant for sensitive applications like medical and food and beverage.

In addition, you'll want to use a desiccant dryer to reach the lowest possible pressure dew point (PDP). You can read more about that in a related article.


Since filters experience constantly fluctuating conditions, including heat, pressure levels, humidity, and chemical reactions, it's important to replace them every 12 months, at minimum.

Not doing so could result in unexpected downtime, reduce efficiency, and lead to quality control issues in your end product. In addition to following this guideline, you'll want to properly dispose of waste condensate through a water separator.

Water separators

Since filtration and drying remove contaminated water vapor (moisture), you'll need a way to separate this for draining. This is especially important if you're using an oil-injected setup. It's required to meet environmental regulations for disposing of such impurities.

Using centrifugal technology, a separator removes 99% of bulk water. Completing the process are various drains, including manual, automatic, and level-controlled. Our equipment is tested and certified to meet government regulations.

We're here to help

We hope this guide provides a good overview of the different filter types you'll encounter when installing a comprehensive air treatment system.

If you have any questions about what makes the most sense for your applications and needs, feel free to reach out. Our team is happy to help point you in the right direction.