ISO Coarse Filters

About ISO Coarse Filters

ISO Coarse filters are used to capture larger airborne particles before air passes to finer filtration stages. According to ISO 16890, this classification applies to filters that achieve at least 50% arrestance for particles larger than 10 micrometers. These filters are commonly installed as the first stage of air filtration in HVAC systems, industrial ventilation equipment, and air handling units.

Their primary role is to reduce dust loading on downstream filters, maintain cleaner airflow through the system, and support more stable long-term operation. In many applications, ISO Coarse filters serve as a practical and cost-effective solution for initial particulate control.

Typical Particle Size

ISO Coarse filters are mainly designed for particles:

• ≥10 µm

These larger particles typically include:

• dust
• fibers
• lint
• sand
• pollen
• larger airborne debris

Key Features

• Effective removal of coarse dust and fibers
• Low initial pressure drop
• High dust holding capacity
• Cost-effective pre-filtration solution
• Helps protect downstream fine and high-efficiency filters
• Supports longer service intervals in multi-stage systems

Typical Applications

ISO Coarse filters are commonly used in:

• Commercial HVAC air intake systems
• Industrial ventilation systems
• Manufacturing facilities
• Air handling units (AHUs)
• General building ventilation
• First-stage filtration in multi-stage air filtration systems

They are especially suitable where the main objective is to remove larger particles efficiently before finer filters take over.

Selection Considerations

ISO Coarse filters are typically selected when low resistance, high dust holding capacity, and economical pre-filtration are the main priorities. They are often used in systems where air first passes through a coarse filter stage before moving to ePM10, ePM2.5, ePM1, or HEPA filtration.

When selecting ISO Coarse filters, important factors include:

• airflow volume
• installation size
• dust concentration
• maintenance interval
• downstream filtration requirements
• energy efficiency goals

A properly selected ISO Coarse filter helps improve the overall performance of the full filtration system by reducing unnecessary loading on higher-efficiency filters.

ISO Coarse vs F-G Class Filters

ISO Coarse is part of the ISO 16890 standard, which replaced the former EN 779 classification system. In practical use, ISO Coarse filters broadly correspond to former low-efficiency G-class filters such as G2, G3, and G4, depending on actual product performance.

However, ISO 16890 and EN 779 are based on different test methods and classification principles. For this reason, ISO Coarse should not be treated as a strict one-to-one replacement for any single EN 779 grade. Instead, it is best understood as the modern standard for coarse particulate filtration.

Why ISO Coarse Filters Are Used in Multi-Stage Systems

In many HVAC and industrial air systems, using only one filter stage is not enough. ISO Coarse filters are often installed upstream to capture larger particles first. This helps:

• reduce premature clogging of finer filters
• maintain lower overall system pressure drop
• extend the service life of downstream filters
• improve maintenance efficiency
• support more stable air system operation

This makes ISO Coarse filters an important part of staged air filtration design.

ISO 16890 Coarse FAQ

What does ISO Coarse mean under ISO 16890?

ISO Coarse means the filter removes at least 50% of particles larger than 10 micrometers according to the ISO 16890 test method.

Where are ISO Coarse filters typically used?

ISO Coarse filters are commonly used in commercial HVAC systems, industrial ventilation systems, manufacturing facilities, and as the first filtration stage in multi-stage air handling systems.

Are ISO Coarse filters suitable as final filters?

In most cases, no. ISO Coarse filters are generally used as pre-filters and are normally combined with finer filters when higher air quality is required.

Do ISO Coarse filters replace G4 filters?

ISO Coarse filters broadly correspond to former G-class filters, but ISO 16890 and EN 779 use different test methods. Product performance should be evaluated individually rather than treated as an exact one-to-one replacement.

What is the difference between ISO Coarse and ePM10 filters?

ISO Coarse filters focus on larger particles above 10 micrometers, while ePM10 filters are classified based on their efficiency in capturing finer particulate matter up to 10 micrometers.