The ISO 9022-12 standard specifies a contaminated environment test method for optical and photonic instruments. It aims to evaluate the ability of optical instruments and their components to resist contamination when exposed to corrosive chemicals. The standard applies to the environmental suitability testing of optical instruments and related components, including optical components in mechanical, chemical and electronic equipment. Tests evaluate the tolerance of surfaces, coatings or synthetic materials of an instrument by simulating its exposure to corrosive reagents for a short period of time. Test results can be used for material selection, component evaluation, and quality control. The standard also provides detailed test conditions, specimen preparation, test procedures, methods for restoration and evaluation, and specifications for environmental test marking.