HEPA and Better

NHS Air Filtration Supplier since 2000.

Providing Clean Air

HEPA filters have been with us for many years now, and they are great. You’ll find them in medical applications, HVAC systems and even in popular vacuum cleaners. In fact Miele were using HEPA filters in their vacuum cleaners back in the 90s and it was deemed to be a good thing, even then. 

But what is an HEPA Air Filter?


HEPA stands for High Efficiency Particulate Air. HEPA filters are a type of filter made from  finely interlaced fibres of polypropylene or fibreglass with the fibres having a diameter of less than 2 micrometers.These fibres are woven together and then pleated or used in multiple sheets. 

To be classed as HEPA a filter has to remove at least 99.97% of dust, pollen, mould, bacteria, and any airborne particles with a size of 0.3 microns (µm).

You’ll find HEPA filters in a wide range of devices and they are designed to remove a wide range of particles and pollutants from the air in your office, medical facility, home and other buildings. 

Typical HEPA Filter

Diagram of a typical HEPA  filter

Filter Collection Mechanisms

How HEPA and ULPA Filters Trap Pathogens and Particles

All standards evolve in discussion with manufacturers and HEPA is no different.  H13 filters at 99.97% efficacy depend on the test flow used.

An H13 filter may drop considerably in actual performance at higher flow rates. Over the last 24 years we have tried various specifications of filter design, always with the aim of offering assurance to our client base. In medical settings assurance of risk mitigation, in our view, has to be paramount.

At Air Sentry, we wanted to improve on HEPA levels of filtration and to improve the life of the filter so we designed our air filtration units around ULPA (Ultra-Low Particulate Air) filters of our own design. The means that even at maximum flow our systems consistently perform as HEPA 14 units whereas cheaper designs do not.

ULPA filters are similar to HEPA filters in design, with the filter media resembling a large web of randomly arranged fibres. As air passes through this dense web, pollutants and pathogens attach to the fibres and are thus eliminated from the air. An Air Sentry filter is a sandwich. As well as using 2 layers of filter medium, we sandwich a carbon filter between them.

As well as their use in the medical field to reduce the circulation of pathogens and pollutants you’ll find ULPA filters in specialised applications such as microelectronics manufacturing, removing particulates from cleanrooms.

We designed our filters to remove at least 99.9992% of dust, pollen, mould, bacteria and any other airborne pollutant with a particle size of 0.3µm, our worst performance point. Due to the way ULPA filters work, smaller particles become trapped far easier, as of course do larger ones.

With an Air Sentry filter all known pathogens in environmental air are trapped when they enter the filter with 100% assurance. This assurance is arrived at because each filter is independently verified to the clean room standard EN14644. With a known performance we then retest each filter in the unit before handing it over to the onboard computer to check it every 5 minutes, 24/7.

As well as trapping these tiny particles, we have designed our air filters to last for at least 24 months before needing to be replaced, provided they receive a simple service every 12 months. We are so confident of this we are the only company currently to offer a 24 month warranty on our filters.

Not only are our filters designed in the UK by Air Sentry, specifically for use in the medical sector, but we also have them manufactured in the UK too, to reduce the impact of CO2 generated when shippedt

When you see an Air Sentry Air Purification system in use you know that your atmosphere is guaranteed to be clear of pollution, pathogens and PM2.5s.

If you want to learn more, just visit our website, call 01666 818 087, fill in the form below or email webrequest@airsentry.co.uk

Air Sentry K9 Air Filter
An Air Sentry K9 Air Filtration Unit
Air Sentry is effective against all airborne pathogens

Contact us

Book a no obligation consultation with one of our technicians. 

Hospital wards, Nursing homes, Dental clinics and businesses can return to near pre-pandemic daily routine with proper air purification.

Submit your enquiry below and we will respond within two working days. Alternatively call us on 01666 818 087.

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