Regular filter replacement
Filters can only continue to provide the best protection if they are regularly changed. Air flow is hindered by increased soiling as the filter progresses through its working life. The cabin air filter should be changed according to the appropriate stated service interval – in areas with higher pollution levels (e.g. industrial areas or urban conurbations), more frequent changes are recommended, even before the scheduled service intervals.
There’s a demand for cabin air filters the whole year round: from springtime to autumn, the pollens are flying, in summer high ozone concentrations are a menace, and in winter the windows will mist up if the air quality inside the car is poor. There are many good reasons why you should replace the cabin air filter at regular intervals.
VDI Guideline 6032
An automobile’s cabin air filter should be changed after two years at the latest. Highly stressful climatic and operating conditions, such as city driving, will necessitate even shorter intervals between replacements. These stipulations come from a guideline (No. 6032) of the Association of German Engineers (VDI), which since February 2004 has been issued. An honorary VDI committee took less than two years to draw up this guideline, which defines specifications like hygiene and maintenance requirements for the ventilation and air treatment systems in passenger cars. Basically, VDI 6032 demands the installation of cabin air filters in all passenger cars. Freudenberg Filtration Technologies was the only filter manufacturer to be represented on the guideline committee. The filter specialists provided the body with comprehensive expert input.
Changing of the filter guards
Depending on the car ventilation system involved, there are differences in terms of filter utilisation: in the case of vehicles with air conditioning, the VDI demands the installation of an interior filter – a particle or combi-filter – for cleaning the outside air. For ventilation systems without an air-conditioner, the VDI urgently recommends air filtration. The general principle here is: a ventilation system’s operation must not cause the air quality to worsen. This is why, in addition to the design requirements for the ventilation system, it is necessary to install cabin air filter.
VDI 6032 specifies the minimum particle collection efficiency for cabin air filters. The high filter performance ensures that the air passed into the vehicle’s interior has had a very large proportion of particles removed. In addition, the risk of equipment soiling is significantly reduced. In terms of maintenance for cabin air filters and ventilation systems, VDI 6032 specifies the following points for particular attention: secure and easy installation of the cabin filter by appropriately qualified and trained personnel, plus conveniently effective cleaning of the air inlet channel in the vehicle. Moreover, the date of the last filter change has to be visibly documented. A cabin filter’s design is required to ensure that the filtering function is not impaired by mechanical stresses either during actual installation or during operation. This stipulation is best met by the original parts tested and installed by the vehicle manufacturer concerned.
Under the chairmanship of Prof. Dr. Schata, Head of the Institute for Health Research and Hygiene in Düsseldorf, the guideline was defined by representatives from the automotive industries, shipbuilding, railway and air-conditioning manufacturers. The German Federal Ministry for Education and Research (BMBF) and numerous academic organisations like the Institute for Hygiene and Air Purity at Berlin Technical University. It can be obtained from the Beuth Verlag publishers in Berlin.