Automotive Design


Whereas, for example, the German Association of the Automotive Industry (VDA) test requires the pollutant concentrations to be measured in a test cabinet, in Asia the samples are usually packaged in bags and then heated in an oven. The pollutant concentration in the bag is then measured. However, it is difficult to obtain comparable test results because all the carmakers have their own individual test specifications for the bag method, which differ to a greater or lesser extent from the ISO 12219-2 standard.


Benecke-Kaliko has analysed the different specifications with regard to their influence on the result. This involved specifically varying test conditions such as sample preconditioning, oven temperature, oven dwell time, sample size and fill volume of the test bag.


Summarising the results


In the main, the same qualitative results are obtained, i.e. the same substances are identified. However, the situation is different when it comes to the quantitative results, i.e. the pollutant concentration: These results vary greatly, depending on the different test conditions.


Benecke-Kaliko’s analysis showed that the preparation of the samples has the biggest influence. The divergence here can be as much as 2,000%. The second parameter that has a highly significant effect on the result is the oven temperature. The VOC emissions rise by 1,000% and the aldehyde emissions by 300% if an oven temperature of 80°C is specified instead of 60°C.


The tempering period of, for instance, two hours also has to be accurately observed, because the emissions results change substantially with varying times. A variation from oven to oven with different heating characteristics is therefore also to be expected. Changes in the fill volume and different removal rates had little or no effect in Benecke-Kaliko’s labs: increasing


the sample size from 8cm by 10cm to 10cm by 10cm has only a minor effect on the quantitative difference in emissions.


Although sample conditioning has the greatest influence on the measurement result with the bag method, it is not defined at all or is only approximately defined in some specifications. But without a definition as in the VDA 278 method – “Seal promptly after production, condition at room temperature in the test institute for seven days, then test” – very sizable scatter is to be expected with all the bag methods. A common specification of, for example, seven days at room


temperature would therefore be an important prerequisite for obtaining reproducible results.


Now that an appropriate test configuration has been developed and key factors defined,


Dr Roland Freudenmann Global head of laboratories Benecke-Kaliko


Benecke-Kaliko is able to help its Asian customers achieve meaningful results.


In addition, the company is able to enhance the air quality in automotive interiors thanks to its innovative products such as the low-emission Acella Eco. l


For more information ✔ at www.engineerlive.com/asia


Dr Roland Freudenmann is global head of laboratories at Benecke-Kaliko. www.benecke-kaliko.com


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