Difference Between Nominal and Absolute Filtration


In the field of industrial filtration, understanding the difference between nominal and absolute filtration is crucial for selecting the appropriate filter for specific applications. Both filtration types play important roles in various industries, but they offer different levels of filtration efficiency and are suitable for distinct usage scenarios. This article explores the key differences between nominal and absolute filtration and their respective applications.

Nominal Filtration

Definition and Characteristics

  • Nominal Filtration refers to the capability of a filter to capture a certain percentage of particles above a specified size. Typically, nominal filters are rated to capture 60-98% of particles of a given size.
  • Efficiency: The efficiency of nominal filters can vary significantly, depending on the specific application and the filter media used. They do not guarantee the removal of all particles of the specified size.
  • Cost-Effective: Nominal filters are generally less expensive than absolute filters and are suitable for applications where precise filtration is not critical.


  • Water Treatment: Used in preliminary filtration stages to remove larger particles and protect downstream equipment.
  • Industrial Processes: Suitable for applications where removal of larger particulates is sufficient to maintain process integrity.
  • HVAC Systems: Employed in heating, ventilation, and air conditioning systems to improve air quality by removing larger airborne particles.

Absolute Filtration

Definition and Characteristics

  • Absolute Filtration refers to the capability of a filter to capture 99.9% or more of particles of a specified size. Absolute filters provide precise and consistent filtration, ensuring that no particles larger than the specified size pass through.
  • Efficiency: Absolute filters offer a high level of efficiency and are critical in applications requiring stringent contamination control.
  • Higher Cost: Due to their superior filtration capabilities, absolute filters are typically more expensive than nominal filters.


  • Pharmaceutical Manufacturing: Essential for ensuring the purity of products by removing all contaminants above a certain size.
  • Food and Beverage Production: Used to guarantee product quality and safety by providing highly reliable filtration.
  • Microelectronics: Critical in environments where even tiny particles can damage sensitive electronic components.
  • Healthcare: Applied in medical devices and cleanrooms to maintain sterile conditions and prevent contamination.

Business Reach

Omela Filtration Inc. provides high-quality filtration solutions to industries worldwide, including in the United States, Canada, Brazil, Mexico, Argentina, Germany, Italy, France, the United Kingdom, Spain, Belgium, the Netherlands, Luxembourg, Russia, Turkey, Japan, Singapore, South Korea, India, Thailand, Indonesia, Malaysia, Australia, New Zealand, and South Africa. Our extensive global reach ensures that clients receive the best filtration products and support for their specific needs.

For more information on selecting the right filtration solution for your needs, please contact our sales team at Omela Filtration Inc

5/5 - (1 vote)

Related Articles

Jul 20, 2024

Filter Bag Recycling and Reusing from Baghouse Dust Collectors

The recycling and reusing of filter bags from baghouse dust collectors not only reduce operational costs but also contribute to en

Jul 20, 2024

Filter Bags for Carbon Black Dust Collection

Carbon black dust, a byproduct of the carbon black manufacturing process, poses significant health and environmental risks. Effici

Jul 12, 2024

When to Replace Dust Filter Bags in the Cement Plant

Ensuring the optimal performance of dust filtration systems in cement plants is crucial for maintaining production efficiency, mee