scope:

A test method for anthropogenic chemical factors in the form of acid atmospheric precipitation in interaction with climatic conditions has already been described in standard VDI 3958 Part 12. In the present standard, special substances of biological origin are an element of the applicable worst case. These substances are only deposited or form to a high degree on the exposed surfaces of the affected objects in geographically restricted locations within tropical and humid subtropical regions.

The standard covers the testing of the tropicalisation of paint coatings whose function and service life depends primarily on the retention of the demanded properties of their surfaces and areas close to the surface. This standard is confined to the investigation of effects on this part of the paint material.

The standard is concerned, for example, with highgloss paint coatings as used particularly in the automotive industry. Here, the reduction in or even the loss of the desired decorative visual properties can result in the failure of the product concerned (high loss of value).

This standard is demarcated from standard test methods that determine the weather resistance of coatings (e.g. DIN EN ISO 2810 and DIN EN ISO 11507) as follows:

• It deals solely with the high-gloss surfaces of products that are used among other things in environments with a tropical or humid subtropical climate.
• For the testing of tropicalisation under the present standard under natural environmental conditions (natural weathering), only specially selected weathering sites within tropical or humid subtropical regions are suitable.
• The test of tropicalisation under the present standard involves the simulation of a special environmental situation that is only encountered in environments with tropical or humid subtropical climates and can cause a special form of damage, i.e. pitting.
• For the test of tropicalisation in weathering devices under the present standard, the samples are simultaneously exposed to a test dust that simulates the effect of special biological environmental influences.

This standard is targeted at the manufacturers and users of paint coatings for outdoor use and the operators of weathering stations and test laboratories.