With these methods, a material or surface is exposed to the relevant chemical for a longer, defined period of time and the relevant area then inspected microscopically.
Possible changes which could occur include: On completion of the defined test period, any residues of test liquid are removed and the material surface assessed and analyzed for visible alterations in accordance with DIN EN ISO 4628-1 to -5.
[3][4][5][6][7] To ascertain a possible regeneration time, the assessment is made once immediately after removal of the test liquid and again one hour later.
In compliance with DIN EN ISO 4628-1, the following criteria are grouped into Classes 0 to 5: amount of damage (N), size of damage (S) and intensity of alteration (I).
“Blistering, N2-S2” or “Discoloration, I1” Any increase in the concentration of the test liquid on a surface due to drying in the real cleanroom environment must also be taken into consideration.