AATCC 23:1999 pdf download.Colorfastness to Burnt Gas Fumes
7.2 Then remove the test specimens from the test chamber and immediately assess the change in color of each by ue of the Gray Sca’e for Color Change.
7.3 Specimens exposed to oxides of nitrogen may continue to changc color after removal from the test chamber Optionally, another or more detailed visual or instrumental examination may be done. If this is to be done, without delay. plunge the test and control specimens and pieces of the onginal test and control fabric iiao buffered urea solution (see 11.9) for 5 mm. Then squeeze out the specimens and pieces and thoroughly rinse them. Dry the spccimcns in air at a tempcrature not above 60CC.
7.4 After the first cycle, any specimens which do riot show a color change and which are not treated with the buffered urea solution may be returned to the test chamber along with a fresh piece of the test control and the test continued until the second tcst control shows a change in color corresponding to that of the Standard of Fading.
7.5 Cycles may he repeated for either a specified number of cycles or until the specimens show a specified amount of color change.
11.1.1 The exposure chamber may be of vanable conruction but must provide *n enclosure in whiih tcsi spccimcns can be eposed in an atmosphere of air which has passed ovcr and contains the byproducts of combustion from a lighted gas burner. The apparatus should be equipped ith a suitable means of supponing the test specimens so that thcre is a free circulation of the atmosphere around the spccmens arid so that only a minimum amount of the spccimcn at the point of its suspension a in dircct co.itacl with any hot metallic suiface. Either a motor driven fan to move the a,r around in the test chamber or a motor dnvcn rotating specimen rack should be used tn ordcr to insure as ncariy as is possible tha alt specimens are exposed to the same conditions of gas concentration, temperature and humidity. Adjustable vcn(s or dampers in the top of the unit together with the height of thc flame of the gas burner arc uscd to regulate the temperature of the exposure chambcr, but temperature and humidity will vary with that of the room in which the exposure chamber is bcrng operated.AATCC 23 pdf download.