High efficient Particle filtration: EPA / HEPA / ULPA
Range of application
- filtration of to separate airborne particles or particulaire air impurities down to 0,1 µm (i.e. viruses, germs, toxic dusts)
- resistant up to 250 °C
- clean room filtration
- process air
- operation room ceilings
- Laboratories, clean work benches
- for supply and exhaust air
HS-Particulate Filter Cells Type HS-Mikro-S are HEPA / ULPA filters, these filters are installed where the maximum of air cleanliness is demanded. This particulate filter is needed on the air intake side for the separation of suspended matters e.g. viruses, germs, toxic types of dust, aerosols etc.serve. It used e.g. in the medical area according to DIN 1946, in areas like operation rooms, intensive care units, laboratories, and in the precision technique, thus always where germ or dust free air is essential. HS-Mikro-S filters are also installed on the exhaust air side if pathogene, toxic or radioactive particles must be removed from the exhaust air.
HS-Mikro-S-Filters are available in different versions, whereby the filter media us always high-quality high efficiency and superhomogeneous glass fibre paper with different degrees of separation.
The paper is pleated and provided either with aluminum or thermoplastic separators. This arrangement of pleated fibre medium is absolutely leak free connected to the frame of the cell with an elastic non-porous grouting compound.
A higher filter surface is achieved by a special folding and the use of thermoplastic spacers than with conventional HEPA-Filters; thus there are larger flow rates with the same pressure loss and the same flow rates. The difference of pressure will be smaller at the same flow rate. Those filters have a smaller weight than those with spacers made of aluminum, which facilitates the handling enormously.
Schwebstofffilter (EPA / HEPA / ULPA) – Höchste Abscheidegrade für kritische Anwendungen
Schwebstofffilter liefern die höchsten Abscheidegrade im Bereich der mechanischen Luftfiltration. Sie scheiden Partikel bis hinunter zu 0,1 µm zuverlässig ab – darunter Viren, Bakterien, Keime, toxische Stäube, radioaktive Aerosole und submikrone Partikel, die für das menschliche Auge unsichtbar sind. Je nach Klassifizierung spricht man von EPA-Filtern (Efficient Particulate Air Filter, Klassen E10–E12), HEPA-Filtern (High Efficiency Particulate Air Filter, Klassen H13–H14) oder ULPA-Filtern (Ultra Low Penetration Air Filter, Klassen U15–U17).
HS-Luftfilterbau fertigt Schwebstofffilter seit über 45 Jahren in eigener Produktion in Kiel – von EPA-Filtern für industrielle Prozessluft bis hin zu ULPA-Filtern für Halbleiter-Reinräume und kerntechnische Anlagen. Jeder HEPA- und ULPA-Filter kann in unserem eigenen Scantest-Prüfstand gemäß EN 1822 / ISO 29463 einzelgeprüft und mit individuellem Testreport ausgeliefert werden. Unsere Fertigung ist nach ISO 9001, ISO 14001 und KTA 1401 (kerntechnische Qualitätssicherung) zertifiziert.
Filterklassen nach EN 1822 / ISO 29463
Die Klassifizierung von Schwebstofffiltern erfolgt nach der europäischen Norm EN 1822 bzw. der international weitgehend identischen ISO 29463. Entscheidend ist der Abscheidegrad an der MPPS (Most Penetrating Particle Size) – der Partikelgröße, die am schwersten abzuscheiden ist. Die MPPS liegt je nach Filterkonfiguration typischerweise zwischen 0,1 und 0,3 µm.
| Group | Class | Integral efficiency (MPPS) | Local efficiency (MPPS) | Description |
|---|---|---|---|---|
| EPA Efficient Particulate Air |
E10 | ≥ 85 % | – | Efficient Particulate Air Filter |
| E11 | ≥ 95 % | – | Efficient Particulate Air Filter | |
| E12 | ≥ 99,5 % | – | Efficient Particulate Air Filter | |
| HEPA High Efficiency Particulate Air |
H13 | ≥ 99,95 % | ≥ 99,75 % | High Efficient Particulate Air Filter |
| H14 | ≥ 99,995 % | ≥ 99,975 % | High Efficient Particulate Air Filter | |
| ULPA Ultra Low Penetration Air |
U15 | ≥ 99,9995 % | ≥ 99,9975 % | Ultra Low Penetration Air Filter |
| U16 | ≥ 99,99995 % | ≥ 99,99975 % | Ultra Low Penetration Air Filter | |
| U17 | ≥ 99,999995 % | ≥ 99,9999 % | Ultra Low Penetration Air Filter |
Important distinction: EPA filters (E10–E12) are generally classified by means of type testing only – the filtration efficiency is determined as an average value based on sample testing. HEPA and ULPA filters (H13–U17), on the other hand, require individual testing (scan test or oil thread test), in which each individual filter element is tested for integral and local filtration efficiency as well as leak tightness.
Further information on filter classification can be found at www.ISO29463.com and www.ISO16890.de.
Design Types and Construction Principles
HEPA and ULPA filters differ fundamentally in the way the filter medium is pleated and secured within the frame. The selected design determines the available filter area, airflow rate, pressure differential and possible applications. HS-Luftfilterbau offers all commonly used construction principles:
| Design Type | Principle | HS Products | Classes | Typical Applications |
|---|---|---|---|---|
| Aluminium Separator | Classic corrugated aluminium separators for pleat spacing, offering maximum configuration flexibility | HS-Mikro S, HS-Mikro R | E10 – U17 | Nuclear facilities, safety housings, highest requirements, custom designs |
| Minipleat (Flat Design) | Thermoplastic spacers, virtually metal-free and incinerable | HS-Mikro SF, HS-Mikro RF | E11 – U16 | Cleanrooms, pharmaceutical applications, medical applications, process air, universal applications |
| Minipleat V-Form | V-shaped arrangement of minipleat filter packs for maximum filter area | HS-Mikro SFV, HS-Mikro RFV, HS-Mikro Pak SFV/RFV, HS-Deka Pak SFV/RFV | E11 – H14 | High airflow rates, low pressure differentials, replacement of fine dust filters |
| Laminar Flow | Minipleat design with aluminium frame, optimised for uniform, laminar airflow | HS-Mikro SF-AL, HS-Mikro RF-AL | E11 – H14 | Cleanrooms, operating theatre ceilings, clean workbenches, clean benches |
| V-Pak Compact | Compact V-form HEPA filter for mobile and space-saving applications | HS-V-Pak SFV, HS-V-Pak RFV | E11 – H14 | Mobile filtration units, gloveboxes, clean benches, mobile systems |
| Cartridge Filter | Cylindrical filter elements for ductwork and pressure equalisation | HS-Mikroseal JG, HS-Mikroseal JG-S | H13 – H14 | Tank venting, gloveboxes, ductwork (± 300 mbar), safety filtration systems |
| High Temperature | Temperature-resistant media and frames for temperatures up to 250 °C | HS-Mikro SF-HT, HS-Mikro SFV-HT | E11 – H14 | Hot-air sterilisation, high-temperature process air, dryers |
| ATEX Safety Filter | Cleanable HEPA filter, ATEX-compliant, designed for maximum load capacity | HS-Strongshield SF-EX H13 | H13 | Potentially explosive atmospheres, extreme dust loads |
Separator vs. Minipleat: Choosing the Right Design
The two main design types of HEPA and ULPA filters – aluminium separator and minipleat – each offer specific advantages:
| Criterion | Aluminium Separator (HS-Mikro S / R) | Minipleat (HS-Mikro SF / RF / SFV / RFV) |
|---|---|---|
| Filter Classes | E10 – H14 (higher classes available on request) | E10 – U17 |
| Filter Area (same frame size) | up to 88 m² per m² of face area | up to 110 m² per m² of face area |
| Pressure Differential | Higher | Lower (at the same airflow rate) |
| Temperature Resistance | Up to 250 °C (with HT media) | Up to approx. 65 °C (standard), up to 120 °C (HS-Mikro SF-HT) |
| Metal-Free / Incinerable | No (aluminium separators) | Yes (virtually metal-free) |
| Custom Designs | Wide range of options, installation depths of 150 and 292 mm | Maximum configuration flexibility |
| Nuclear Applications | Proven according to KTA 1401 / 10CFR50 | Possible (project-specific) |
| Recommendation | Nuclear applications, safety housings (BiBO), high-temperature applications, heavy-duty applications, custom designs | Cleanrooms, pharmaceutical applications, medical applications, process air, universal applications, energy efficiency |
V-form design as a third option: The HS-Mikro SFV/RFV as well as HS-Mikro Pak SFV/RFV and HS-Deka Pak SFV/RFV combine minipleat technology with a V-shaped arrangement of the filter packs. This provides an even larger filter area within the same installation frame – ideal for applications with high airflow rates where the lowest possible pressure differential is essential. This design is also ideally suited as an upgrade for existing fine dust filter positions: HS-Mikro Pak SFV/RFV and HS-Deka Pak SFV/RFV fit into pocket filter mounting frames, making it possible to increase filtration efficiency to EPA/HEPA level (provided that the leakage class of the filter system permits this) without structural modifications.
Filter Media and Potting
The filtration performance of a HEPA or ULPA filter is largely determined by the filter medium. HS-Luftfilterbau uses two types of filter media:
- Microglass fibre paper: The proven standard medium for HEPA and ULPA filters. Ultrafine glass fibres (diameter < 1 µm) form a dense, highly efficient filter mat. Available in different permeability grades for all filter classes from E10 to U17. Microglass fibre papers offer excellent thermal stability and consistent filtration performance throughout the entire service life.
- ePTFE membranes: Expanded polytetrafluoroethylene membranes as an alternative for applications requiring glass-fibre-free media. ePTFE offers very high filtration efficiencies with a lower pressure differential and excellent chemical resistance.
All HS HEPA and ULPA filters use a permanently elastic polymer as the potting compound, providing a durable, airtight seal between the filter medium and the frame. Gaskets made from various materials and with different profiles can be fitted on one or both sides. For safety-critical installations, HS HEPA and ULPA filters can be equipped with a gasket featuring a seal-seat test groove, allowing subsequent verification of a bypass-free installation.
Individual Testing: Scan Test and Oil Thread Test
The performance of a HEPA or ULPA filter depends critically on its integrity. Even the smallest leaks – in the potting compound, gasket or filter medium – can compromise the overall filtration performance. For this reason, EN 1822 requires individual testing of every filter element for HEPA filters (H13/H14) and ULPA filters (U15–U17).
Scan Test (EN 1822 / ISO 29463)
During the scan test, the filter under test is challenged at its nominal airflow rate with a test aerosol whose mean particle size corresponds to the MPPS. A traversing probe scans the entire clean-air-side surface of the filter in a standardised pattern and measures the local particle number concentrations. At the same time, the upstream concentration is monitored. These data are used to determine the integral filtration efficiency (overall performance) and the local filtration efficiency (weakest point) – both of which must comply with the limits specified for the respective filter class. HS-Luftfilterbau operates an in-house scan test laboratory in Kiel under strictly controlled laboratory conditions (airflow, temperature and humidity).
Oil Thread Test (EN 1822-4)
For HEPA filters of classes H13 and H14, a visual test method is permitted as an alternative to the scan test: An oil mist generator produces an aerosol (particle size spectrum 0.2–0.5 µm), which is passed through the horizontally mounted filter under test. Using a special light source, penetrating particle streams become visible as rising mist threads against a contrasting background. This test is particularly suitable for filter geometries that do not permit automated scan testing and for integrity testing immediately prior to installation. Our mobile HS-Fogtester test system enables this inspection to be carried out directly on site.
Scan Test vs. In-Situ Leak Test (ISO 14644-3)
In addition to the manufacturer's scan test, an in-situ leak test in accordance with ISO 14644-3 is frequently carried out at the customer's site. These two procedures are fundamentally different: The scan test according to EN 1822 / ISO 29463 enables filter classification (E10–U17) under controlled laboratory conditions. The leak test according to ISO 14644-3, on the other hand, only determines whether the installed filter system is leak-tight or not under actual operating conditions – it cannot be used to classify the filter. Environmental factors such as personnel movement, machine activity and temperature fluctuations can affect in-situ measurement results.
A detailed comparison of both test methods can be found on our Fundamentals of Filtration Technology page.
| HS Product | Design Type | Classes (EN 1822) | Standard Installation Depth [mm] | Special Features |
|---|---|---|---|---|
| HS-Mikro S / R | Separator | E10 – H14 | 150 / 292 | Maximum configuration flexibility, KTA 1401, high-temperature applications up to 250 °C |
| HS-Mikro SF / RF | Minipleat | E11 – U12 | 66 / 78 / 150 / 292 | Depending on the design, virtually metal-free, incinerable, suitable for universal applications |
| HS-Mikro SF-AL / RF-AL | Laminar Flow | E11 – U17 | 30 to 150 mm | Uniform airflow for cleanrooms, operating theatre ceilings, clean benches |
| HS-Mikro SFV / RFV | Minipleat V-Form | E11 – H14 | 292 | Maximum filter area, high airflow rates |
| HS-Mikro Pak SFV / RFV | Compact V-Form | E11 – H13 | 292 | Replacement for fine dust filters, fits into pocket filter mounting frames |
| HS-Deka Pak SFV / RFV | Compact V-Form | E11 – H13 | 420 | Energy-efficient, suitable for upgrading existing systems |
| HS-V-Pak SFV / RFV | Compact V-Form | E11 – H14 | Compact design, suitable for mobile filtration units, gloveboxes and clean benches | |
| HS-Mikro SF-HT | High-Temperature Minipleat | E11 – H14 | 150 / 292 | Temperature-resistant up to 380 °C |
| HS-Mikro SFV-HT | High-Temperature V-Form | E11 – H14 | 292 | Combines V-form design with high-temperature resistance |
| HS-Mikroseal JG | Cartridge Filter | E11 – U15 | Variable | Pressure relief, tank venting, gloveboxes |
| HS-Mikroseal JG-S | Cartridge Filter | E11 – U15 | Variable | Installation in ductwork, ± 300 mbar |
| HS-Strongshield SF-EX H13 | ATEX Safety Filter | H13 | 292 | Cleanable, ATEX-compliant, designed for maximum load capacity |
Options for all design types: Metal frames, special gaskets (gel seal, flat gasket, round cord gasket), gasket with seal-seat test groove, protective grilles, handles, flanges, cleanable filter media and custom dimensions. Temperature resistance up to approx. 65 °C (standard), up to 250 °C (HT versions).
Applications
HEPA and ULPA filters are used wherever virtually germ-free or dust-free air is essential – for both supply air and exhaust air applications:
Supply Air Applications
- Cleanrooms, Pharmaceuticals and Medical Applications: HS-Mikro SF-AL as a terminal filter in cleanrooms (ISO 14644), operating theatre ceilings (DIN 1946-4), intensive care units, laboratories, fan filter units and clean benches. HS-Mikro SF/SFV as process air filters in pharmaceutical production.
- Microelectronics and Semiconductors: ULPA filters (U15–U17) from the HS-Mikro S/R series for cleanrooms of the highest cleanliness classes (ISO 1–3). These applications require the strictest standards for local filtration efficiency.
- Precision Engineering and Optics: Particle-free process air for surface treatment, coating processes and optical manufacturing.
- Food Production: Sterile air for aseptic filling and packaging. Incinerable minipleat versions (HS-Mikro SF) simplify disposal.
Exhaust Air Applications
- Nuclear Applications: HS-Mikro S/R filters for safety filtration systems in nuclear facilities – manufactured in accordance with KTA 1401 (upon request we certify 10CFR50 on project basis). HS-Mikroseal JG cartridge filters for pressure relief and tank venting in contaminated areas. Our mobile filtration units have proven their reliability in numerous applications at nuclear facilities.
- BSL-3 / BSL-4 Laboratories: Exhaust air filtration of pathogenic aerosols in biological safety laboratories. Gaskets with seal-seat test grooves and safe-change housings (BiBO – Bag-In/Bag-Out) enable contamination-free filter replacement.
- Toxic and Chemical Exhaust Air: Removal of toxic dusts, welding and soldering fumes, aerosols and other particulate airborne contaminants before the air is discharged into the environment.
- Potentially Explosive Atmospheres: HS-Strongshield SF-EX H13 as a cleanable HEPA safety filter, ATEX-compliant and designed for maximum loads in potentially explosive atmospheres.
Pre-Filtration: Ensuring Service Life and Cost Efficiency
HEPA and ULPA filters are the most cost-intensive filtration stage in an air filtration system. Their service life depends significantly on the quality of the upstream filtration stages. Properly designed pre-filtration protects HEPA and ULPA filters from premature loading and can extend their service life many times over.
Typical pre-filtration combinations:
| Final Filter | Recommended Pre-Filtration | HS Products for Pre-Filtration Stages |
|---|---|---|
| EPA (E10–E12) | Stage 1: ISO Coarse / ePM10; Stage 2: ePM1 55–95% | HS-Alpha Pak + HS-Pak 88 or HS-Mikro Pak 4V |
| HEPA (H13–H14) | Stage 1: ISO Coarse / ePM10; Stage 2: ePM1 80–95% | HS-Alpha Pak + HS-Pak 95 or HS-Mikro Pak 4V PPE |
| ULPA (U15–U17) | Stage 1: ISO Coarse / ePM10; Stage 2: ePM1 95%; Stage 3: EPA (E11/E12) as an intermediate stage | HS-Alpha Pak + HS-Mikro Pak + HS-Mikro Pak RFV (E11) |
Upgrading existing systems: The HS-Mikro Pak SFV/RFV and HS-Deka Pak SFV/RFV in EPA/HEPA versions fit into existing pocket filter mounting frames. This allows the filtration efficiency of existing systems to be upgraded to EPA or HEPA level – without modifying the filter housings or ventilation system.
Quality and Certifications
- State-of-the-art scan test laboratory: HEPA/ULPA scan testing in accordance with DIN EN 1822 and ISO 29463 at our test laboratory in Kiel. Each filter can be supplied with an individual, serial-numbered test report – including documentation of integral and local filtration efficiencies as well as all test conditions.
- KTA 1401: Approved for quality assurance in nuclear facilities. Supplemented by 10CFR50 and GOST compliance for international projects.
- ISO 9001 / ISO 14001: Certified quality and environmental management systems.
- In-house production: Pleating machines, manufacturing robots and scan test equipment at our Kiel facility. Three-shift production enables short response times – including overnight production for unplanned shutdowns.
- Service: Professional installation, hygienic acceptance testing in accordance with applicable standards, and maintenance by our own service team – including Sundays and public holidays.
- CFD simulations: For new developments and customer-specific solutions, we use Computational Fluid Dynamics to optimise airflow and filter performance.
Frequently Asked Questions About HEPA and ULPA Filters
What is the difference between EPA, HEPA and ULPA?
The three designations differ in their filtration efficiency at the Most Penetrating Particle Size (MPPS): EPA filters (E10–E12) achieve efficiencies of at least 85–99.5%, HEPA filters (H13–H14) at least 99.95–99.995%, and ULPA filters (U15–U17) at least 99.9995–99.999995%. EPA filters are typically assessed by type testing, while HEPA and ULPA filters require individual testing (scan test or oil thread test) of each filter element. Classification is carried out in accordance with EN 1822 or ISO 29463.
What is a scan test and why is it important?
The scan test is a test procedure according to EN 1822 / ISO 29463 in which each individual HEPA or ULPA filter element is tested under laboratory conditions for filtration efficiency and leak tightness. A traversing probe scans the entire filter surface and measures local particle concentrations. The scan test enables the determination of both integral and local filtration efficiency and the assignment of the appropriate filter class. HS-Luftfilterbau operates its own scan test facility in Kiel. Each filter can be supplied with an individual test report.
When should I choose separator filters and when minipleat filters?
Separator filters (HS-Mikro S/R) with corrugated aluminium separators are the right choice for nuclear applications (KTA 1401), high-temperature applications up to 250 °C, filter classes E10 to H14, and applications requiring maximum customisation options. Minipleat filters (HS-Mikro SF/RF/SFV/RFV) provide larger filter areas relative to the same frame size, lower pressure differentials and can be designed to be virtually metal-free and incinerable. They are ideal for cleanrooms, pharmaceutical and medical applications, as well as universal applications where energy efficiency is a priority.
Can HEPA filters replace existing pocket filters?
Yes – with certain limitations. Conventional HEPA filters have significantly higher pressure differentials than pocket filters and may overload existing fans. With the HS-Mikro Pak SFV/RFV and HS-Deka Pak SFV/RFV, HS-Luftfilterbau offers compact V-form HEPA filters that fit into standard pocket filter mounting frames. In many cases, these allow an upgrade to EPA or HEPA level without structural modifications. However, checking the available fan capacity and the leak tightness of the filter housing is still recommended, as the final pressure differential, for example, may be higher.
Which HS HEPA filters are approved for nuclear applications?
HS-Luftfilterbau is certified according to KTA 1401 (nuclear quality assurance) and 10CFR50. In particular, the HS-Mikro S/R series with aluminium separator technology is used in nuclear safety filtration systems worldwide. In addition, HS-Mikroseal JG cartridge filters provide the required leak tightness for pressure equalisation in contaminated areas under both positive and negative pressure conditions. HS mobile filtration units equipped with HEPA filters have proven their reliability in numerous nuclear applications.
How long does a HEPA filter last?
The service life of a HEPA filter depends strongly on the quality of the pre-filtration and the dust load. In cleanroom applications with effective three-stage pre-filtration, service lives of 3 to 5 years are common. In standard applications with two-stage pre-filtration, 1 to 3 years is realistic. In exhaust air applications with high contaminant loads, more frequent replacement may be necessary. The final pressure differential is the key criterion – continuous differential pressure monitoring is therefore recommended.
What does MPPS mean for HEPA and ULPA filters?
MPPS stands for Most Penetrating Particle Size – the particle size at which a HEPA or ULPA filter exhibits its lowest filtration efficiency. Depending on the filter configuration, the MPPS is typically between 0.1 and 0.3 µm. For very small particles, diffusion is the dominant filtration mechanism and efficiency increases; for larger particles, inertial effects become more significant and efficiency also increases. The MPPS represents the minimum between these mechanisms. EN 1822 deliberately classifies HEPA and ULPA filters at this most challenging particle size to ensure a conservative assessment of filtration performance.
Are HS HEPA and ULPA filters incinerable?
The minipleat versions (HS-Mikro SF, HS-Mikro SFV, HS-Mikro Pak SFV, HS-Deka Pak SFV) with MDF or plastic frames and thermoplastic spacers are virtually metal-free and fully incinerable. Separator filters (HS-Mikro S/R) with aluminium separators and metal frames must be disposed of as metal-containing waste. HS-Mikro SF-AL filters with aluminium frames are not completely incinerable, but the aluminium can be easily recycled.
Request a Quote or Order HEPA and ULPA Filters
A selection of standard filters is available from our online shop at www.luftfilter.kaufen. For custom-made filters, projects requiring scan testing, nuclear specifications or technical advice, please contact us directly:
- Phone: +49 (0) 431 71953 0
- Email: info@luftfilterbau.de
Do you work, conduct research or manufacture products in critical environments? We will be happy to advise you on the optimum filtration solution – from specification and individual testing through to professional installation and on-site acceptance testing.
