Engine & Turbine Technology
classification of filters. Te Eurovent Guideline 4/11 – Energy efficiency classification of air filters for general ventilation purposes, is ready and published on the Eurovent web site. Starting in January 2012, Eurovent Certification
will certify all fine filters, that will be assigned an energy efficiency class (A to G) tested according to EN779:2011. Tey will also be classified according to their annual energy consumption, initial efficiency and minimum efficiency (ME).
A welcomed initiative Te new European standard for air filters (EN779:2011) comes into force in autumn 2011. Its purpose is to classify air filters based on their minimum filtration efficiency (ME) on 0.4µm particles. Te industry has now voted for tougher requirements for air filters and the standard has been published in August this year. National versions will be available in mid-November, after which the former standard will no longer apply. Te new standard will help eradicate a number of
problems related to filter performance. One of these problems is associated with electrostatic-charged synthetic filters. Tese filters usually demonstrate good initial filtration efficiency while they keep their charge, but tend to discharge extremely rapidly, often after just a few weeks of operation. F7 performance in the lab for an electrostatic-charged filter can therefore decrease to F5 in real operating conditions, and sometimes even
more. Teir cleaning ability deteriorates considerably as a result. Unfortunately, far too many European buildings are now using electrostatic-charged F7 filters that have medium efficiency (ME) values between 5 and 10 per cent.
As a consequence, as much as 90 to 95 per cent of the contaminants in outdoor air find their way into buildings and pollute the indoor environment. By basing classification on an ME of at least
35 per cent for F7, the new EN779:2011 standard will force these filters out of the market. At the same time, it will contribute to the development of synthetic filter materials offering considerably higher particle separation.
Not all filters are the same Regrettably, the price for this will include higher pressure drops and increased energy consumption. Tere is one major concern about the new classification: while the ‘worst’ filters will vanish from the market, there is a possibility that “good” filters will be made ‘worse’. Although energy savings can be achieved by having the lowest possible pressure drop, such development could be retrograde. ●
Enter 37 or ✔ at
www.engineerlive.com/ipe
Richard Ringström is Product Manager, Gas Turbine Filters, Camfil Farr Power Systems, Boras, Sweden.
www.camfilfarr.com/ps
Circle 37A or ✔ at
www.engineerlive.com/ipe
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