Colorfastness to nitrogen oxides

This method is intended for determining the resistance of the colour of textiles of all kinds and in all forms to the action of nitrogen oxides produced during combustion of gas, coal, oil, etc., and when air is passed over heated filaments.
Two tests differing in severity are provided;

one or both of them may be used depending on the requirement.

Specimens of textiles are exposed to nitrogen oxides, In a closed container until either one or three test-control specimens exposed simultaneously with the test specimens have changed in colour to a predetermined extent. The change in colour of the specimen is assessed with the grey scale.

For more detail click here:http://www.dfmg.com.tw/member/standard/bs/BS-g01.HTM