In hygienic-technical regulations, among other things, requirements are also placed on materials which are installed in HVAC systems or evaporative cooling systems. For example, it is required that materials in the air-conducting area are corrosion-resistant or, if they are plastics, that they cannot be metabolized by microbes. Whether plastic materials meet this requirement can be tested, for example, according to DIN EN ISO 846 procedure A and C. If fungicides are used in the materials, the effectiveness can be tested using Procedure B.
The chemical resistance of materials to various cleaning agents and disinfectants is also relevant, or cleaning tests to show that plant surfaces can be cleaned and disinfected. Furthermore, the emission behavior of materials is also of interest.

DIN EN ISO 846 "Determination of the effect of microorganisms on plastics" Procedure A, B and C

Method A is used to assess the basic resistance of plastics to fungal attack in the absence of organic contaminants.
Method B is suitable for testing the fungistatic or fungicidal effectiveness of a material.
Method C is used to assess the principal resistance of plastics to bacterial attack in the absence of organic impurities.

For the test according to DIN EN ISO 846 "Determination of the effect of microorganisms on plastics", the test specimens are inoculated under defined conditions with test fungi for method A and with a bacterium for method C and incubated in a nutrient-free environment. After 4 weeks of incubation, the microbial growth is assessed visually.

For Procedure A, the following test fungi are used:

• Aspergillus niger
• Penicillium pinophillum
• Paecilomyces variotii
• Trichoderma virens
• Chaetomium globosum

For procedure C, the following bacterial strain is used:

• Pseudomonas aeruginosa

For the tests we need 30 test specimens per material. The test specimens must have a size of 50 mm x 50 mm x ≤ 6 mm. For paint or varnish materials, you should ideally use glass or stainless steel platelets as a coating base.

Chemical resistance

In this test, test specimens of the material to be tested are wetted with or immersed in the selected test substances under defined conditions with regard to exposure time, concentration and test temperature, depending on the selected method. After the exposure time, the test specimens are examined for visual changes with regard to detachment / abrasion, discoloration / changes in gloss, blistering / swelling / softening, rusting / corrosion and cracking.

For the test we need 14 test specimens per material. These should have a minimum size of approx. 50 mm x 50 mm or Ø 50 mm.

The test conditions are to be determined with the customer before the start of the test and should take into account the conditions in the application.

Emission chamber testing

We offer a worst-case short-term test in which the sample material is stored at room temperature for 3 days in an airtight test chamber without air exchange or humidification. The test is carried out in accordance with the "Requirements for indoor air quality in buildings: health assessment of emissions of volatile organic compounds (VVOC, VOC and SVOC) from building products" of the Committee on Health-related Evaluation of Building Products (AgBB - June 2021).

For the tests, we require 2 test specimens per material, each with an area of 100 mm x 100 mm.

Cleanability tests

In order to permanently guarantee hygiene for an air handling system, it is also necessary to ensure cleanability and disinfectability. For this purpose we offer different tests.

For this test we need one component or three test specimens per material. The test specimens should have a size of approx. 200 mm x 200 mm. In case of tests of systems consisting of several components, e.g. duct systems, a test set-up is necessary, which will be arranged individually after consultation.