New C-Class awarded allergy label
Mercedes-Benz has been awarded the Seal of Quality of the European Centre for Allergy Research Foundation (ECARF) for its passenger cars. This makes Mercedes-Benz the only vehicle manufacturer to bear this seal. The ECARF Seal of Quality is used by ECARF to designate products that have been scientifically tested and proven to be allergy-friendly. Alongside comprehensive testing for inhaled and contact allergens, Mercedes-Benz has been testing the interior emissions of all its model series for 22 years now. And a team of olfactory experts works to ensure that odours in Mercedes-Benz vehicles remain at a consistently pleasant level.
“We are delighted that the allergy-friendly nature of our Mercedes-Benz passenger cars has now been scientifically and independently recognised through the award of the ECARF Seal,” commented Dr Jörg Breuer, Director Certification, Regulatory Affairs & Environment at Daimler AG. “Indeed, the constant improvement of air quality in the interior has for many years now been a key aspect of the development of components and materials for Mercedes-Benz vehicles.”
“In our estimation, Mercedes-Benz currently represents the benchmark in terms of allergen optimisation for vehicles,” according to Professor Dr Torsten Zuberbier, Director of the European Centre for Allergy Research Foundation (ECARF), which is based at the Charité university hospital in Berlin.
The new C-Class is the latest Mercedes-Benz model to have received the ECARF Seal of Quality. The conditions of certification have been met by all model series launched in recent years, from the A-Class to the S-Class. The criteria behind the ECARF Seal are also included in the specifications book for all future Mercedes-Benz passenger car model series.
The emphasis on clean air applies for Mercedes-Benz in three particular areas: along with the avoidance of allergens, the concern is to reduce interior emissions and to keep odours at a consistently pleasant level. “We have been measuring the interior emissions of our vehicles since 1992 and have been able to make steady progress in reducing them,” according to Dr Breuer. “We have a strict internal limit these days, which has to be met by all Mercedes-Benz passenger cars – by our compact vehicles and roadsters but equally by our large estates and SUV models.”
There are currently a dozen or more experts working in the development and materials technology area on the interior air quality of new models. Over the course of the coming year, the team will also be moving into a new test centre at the Mercedes-Benz Technology Centre in Sindelfingen – a fact which also serves to emphasise the importance given to this topic.
Even in the early stages of the development of a vehicle, up to six years before it goes into production, the minimisation of interior emissions is a factor helping to define the materials concept. As far back as 1996, Mercedes-Benz’s own internal standards set emission levels for materials used for components in the passenger compartment and boot. Today designers and developers can make their choice from a database of around 8000 interior materials that have been approved by the specialist department.
Just before a new model goes into series production, its interior emissions are tested in a series of complex procedures. This type of analysis has been conducted by Mercedes-Benz since 1992. Component assessment involves the testing of numerous parts from each equipment variant of a model series – door panels and seats as well as the roof liner and trim. In order to ensure that a realistic impression is gained, the team do not use specially produced sample components but standard production components produced using the tools that will be subsequently used for series production. The testing procedure prescribes adherence to the VDA 276 standard as laid down by the German Motor Industry Association – the components are stored and measured in a test chamber 1 m3 in size at a defined temperature, humidity level and air circulation rate. Air samples are then extracted and used to measure the quality and quantity of gaseous substances in the air.
The examination of the vehicle as a whole involves an even more complex process. The necessary preparation of the vehicle alone, in other words the installation of the measuring equipment, takes the well-rehearsed team three quarters of an hour, while the measurements themselves last a full week. The test chamber is lined with stainless steel in order to prevent it giving off emissions of its own. Large radiant heaters are used to simulate the sun and heat up the interior of the vehicle, since for physical reasons emissions are greater under the influence of heat. The solar irradiance is measured by special devices called pyranometers.
Inside the vehicle, as many as ten sensors are used to record the temperature in various areas, for example on the top of the dashboard. A rotating paddle stirs up the air inside the vehicle to ensure an even mix. Overall emissions within the vehicle are calculated with the help of a rack-mounted flame ionisation detector. The rack projects into the vehicle interior over the opened window on the driver’s side, which has been made airtight and emission-neutral with the aid of aluminium foil.
If taking measurements according to test method FAT AK 26, for example, measuring can begin as soon as a temperature of 65 degrees Celsius has been reached at the level of the driver’s nose. Samples of air are extracted from the interior and the air flow directed into a series of test tubes. The chemical composition of the evaporated substances is then analysed in the laboratory.
“We use different sampling techniques for the various categories of substance that we analyse,” explains Hartmut Kovacs, Design for Environment, Head of Interior Emissions at Mercedes-Benz. “All in all, we take more than 100 samples from each vehicle.” As well as the overall emissions, it is therefore also possible to measure the emissions of individual organic compounds.
The emissions experts also look at a vehicle’s propensity to fogging – in other words the creation of a film of condensable substances on a car’s windscreen: the measuring rack therefore also includes a cooled sheet of glass upon which these less volatile substances, if present, are deposited.
In addition to this static test, a further series of tests are used to evaluate emission activity in the interior of the vehicle while it is in use. These tests take place with the engine running and the air-conditioning system switched on, with and without air recirculation. A further touch involves the driver’s door being opened once during each measurement cycle to simulate the driver getting into the vehicle.