EN 1822 and HEPA: Understanding H13, H14 and Test Standards

If you’re selecting a high-efficiency air filter for a commercial or industrial project, the terms EN 1822, H13 and H14 can be easy to mix up. They are not just labels on a datasheet; they describe how a filter is tested, how its performance is classified, and where it may be suitable in a mechanical services design.

At Total Air Filtration, a family-owned air filter manufacturer and supplier in Hillcrest, Brisbane QLD, we regularly help facility managers, mechanical contractors and industrial buyers work through these details and choose filters that suit the system, the site and the application.

What EN 1822 actually measures

EN 1822 is the test and classification standard most often associated with HEPA and ULPA filters. It focuses on the filter’s efficiency at the most penetrating particle size (MPPS), which is the particle size that is hardest for that filter to capture.

That matters because a filter does not perform the same way against every particle size. A filter that is very efficient overall may still have a specific particle size range where performance is slightly lower. EN 1822 is designed to measure the filter at that critical point, rather than relying on a broad average.

In practical terms, EN 1822 helps answer questions such as:

• •How efficient is the filter at its most challenging particle size?
• •Does the filter meet the claimed HEPA class?
• •Is the filter appropriate for a high-efficiency application where particle capture is important?

The standard also includes requirements for leak testing and classification. That is one reason it is commonly referenced when a project needs more than a general-purpose dust filter.

What H13 and H14 mean

Under EN 1822, the HEPA classes identify filters by their measured efficiency at MPPS.

H13

H13 filters have an efficiency of at least 99.95% at MPPS under EN 1822.

That makes H13 a high-efficiency class often specified where fine particle capture is important and the system design can support the pressure drop and installation requirements.

H14

H14 filters have an efficiency of at least 99.995% at MPPS under EN 1822.

H14 sits above H13 in the HEPA range and is typically chosen where a higher level of particle capture is required by the application, the process, or the relevant project specification.

What the class does not tell you

A HEPA class alone does not tell you everything about suitability. You still need to consider:

• •filter size and frame style
• •airflow rate and system resistance
• •housing and seal arrangement
• •available space for installation
• •whether the filter is part of a terminal, ceiling, or in-line arrangement

A correctly rated filter can still perform poorly if it is the wrong physical size or not installed in a suitable housing. If you need help measuring an existing filter, see how to measure an air filter.

HEPA, EN 779 and ISO 16890 are not direct conversions

It is common to see people try to convert MERV, EN 779 or ISO 16890 values straight across to HEPA classes. That is not a reliable approach.

These standards measure and describe performance in different ways:

• •EN 779 used classes such as G3/G4 and F5–F9, and those terms are still widely used in Australia even though the standard has been superseded by ISO 16890
• •ISO 16890 classifies filters based on their ability to capture particulates in different size ranges
• •EN 1822 classifies HEPA and ULPA filters using MPPS efficiency and leak testing

Because the standards are different, there is no simple conversion table that works for every product or every application. A filter that is suitable under one rating system may not be equivalent under another.

For general commercial systems, you will often still see EN 779-style language in specifications, especially where legacy plant or replacement programs are involved. For higher efficiency requirements, EN 1822 is the standard to look for.

Where high-efficiency filters are typically specified

H13 and H14 filters are usually found where the system designer needs tighter control over airborne particles than a standard HVAC filter can provide. Common applications include:

• •cleanrooms and controlled environments
• •pharmaceutical and laboratory spaces
• •medical and healthcare-related facilities
• •electronics and precision manufacturing areas
• •specialist process areas with fine particulate concerns
• •certain terminal filtration or final-stage filtration arrangements

They may also be used in retrofit projects where an existing system is being upgraded and the design allows for the additional resistance and housing requirements.

That said, a high-efficiency filter is not always the right answer for every building. The correct choice depends on the purpose of the space, the existing air handling plant, and the broader ventilation design.

If your project needs to align with building ventilation expectations, AS 1668.2:2024 is often part of the conversation. Site requirements should always be confirmed with the mechanical services engineer or building owner.

What facility managers and contractors should check before ordering

Before choosing an EN 1822 HEPA filter, it helps to confirm a few practical details.

Check the system design

Make sure the air handling unit or filter housing is designed to accept the required filter class. Higher efficiency usually means higher resistance, so the fan capacity and system layout need to suit the selected product.

Check the fit

Measure the filter carefully and confirm the frame style, depth, gasket or seal arrangement, and any holding frame dimensions. If you are replacing an existing filter, the original label is useful, but it should not replace a physical check. Our guide to how to measure an air filter can help.

Check the maintenance approach

Inspection frequency depends on the system, site conditions and dust load. Follow the filter and equipment manufacturer instructions, and monitor pressure drop where gauges are fitted. If a filter housing includes leak testing or integrity checks, those should be carried out according to the site’s maintenance program.

Check whether washable is actually relevant

Some filters are designed to be washable - check the product instructions. That does not apply to every filter type, and it should never be assumed from appearance alone.

Common mistakes when specifying HEPA filters

A few issues come up again and again during replacements and upgrade projects.

• •assuming all HEPA filters are interchangeable
• •treating H13 and H14 as the same thing
• •using an old MERV or EN 779 reference as if it were a direct HEPA equivalent
• •ordering by size only and overlooking frame, seal and housing details
• •ignoring the impact of pressure drop on the system
• •selecting a filter without confirming the intended application

These problems can lead to poor fit-up, excess resistance, or a filter that simply does not suit the job. Taking the time to match the specification properly is usually far easier than correcting a mismatch on site.

Choosing the right filter for the application

For many projects, the key question is not just “What is the highest class?” but “What does the system actually need?” A lower class may be appropriate for pre-filtration, while H13 or H14 may be needed as a final stage in a more specialised environment.

If you are planning a new installation, replacing existing filters, or reviewing a specification, it helps to work from the actual system details rather than assumptions. Our team can help with standard and custom air filters, and we also support ongoing filter servicing for suitable commercial setups.

For broader supply needs across different sectors, see our products and industries we supply.

Need help matching the standard to the job?

Total Air Filtration can supply or make the right filters for your application, from standard commercial products through to higher-efficiency options specified to EN 1822. Call 07 3800 3448 or request a quote, and we will help you work through the filter type, size and application fit.