1.1 This guide covers a testing technique that may be used for comparing the cleaning and whitening or brightening performance of home laundering products or home laundering procedures. This testing is done on naturally soiled family items in home laundering equipment in a laboratory under controlled conditions on a paired comparison basis. As many as four detergents have been put into order by evaluating the set of matched garments two at a time. Use the standards referenced in Section 2 if instrumental readings in addition to human panelists are desired.

1.2 There is no single assessment that will give the overall performance of laundry product. A single test can only predict how products compare under the particular conditions chosen for evaluation and cannot be expected to reflect their comparative performance under the many other possible conditions of use. A series of assessments is always necessary in order to evaluate the many aspects of product performance. While there are laboratory methods of measuring individual aspects of performance (for example, redeposition, solubility), it is necessary to conduct confirming tests under controlled but practical home laundering conditions to simulate consumer experience more closely.

1.2.1 Among the variables that can affect the performance of home laundering products or procedures and that shall be considered in designing tests for their evaluation are: type of fiber, fabric construction, fabric finish, types of items to be washed, load size, kind and level of soils or stains, water hardness, water temperature, pretreatments, the presence of various laundering aids, the concentration of products in the laundering solution, sequence of addition of products, water, laundry, wash time, rate and type of agitation, spin speed, drying or ironing methods, and conditions under which the items are judged.

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.