If you think about how you spend your time during weekends, it is highly likely that at least part of it is dedicated to doing the laundry. Indeed, washing machines and washer-dryers are probably among the most common electric apparel in our households: they come in all shapes and for all tastes, and learning how to wash clothes properly can take some time. All of us have at least once worried about correctly separating coloured and white clothes, or about the best programme to use in order not to ruin them. Another specific worry is to know that our clothes have been properly rinsed.
The determination of rinsing effectiveness is possible thanks to the recently published CLC/TS 50677:2019 ‘Clothes washing machines and washer-dryers for household and similar use - Method for the determination of rinsing effectiveness by measurement of the surfactant content at textile materials’.
As per its name, this Technical Specification focusses on the rinsing effectiveness of household washing machines, washer dryers and commercial washing machines, providing a method for testing it by measuring the surfactant content at textile materials. How the method works is detailed in the TS’ text: basically, it is based on determining the amount of residual linear alkylbenzene sulfonate surfactant (LAS),a chemical which is a key ingredient in most detergents by measuring the UV light absorbance at the wavelength particular to the amount of residual LAS, extracted from the unstained test swatches of the strips used in the washing performance test.
Assuming a fixed linear relationship between LAS amount and quantity of detergent mixture and using a concentration versus absorbance curve developed as part of this procedure, the absorbance values are then converted into detergent concentrations, which in turn are used to express the amount of LAS as determined by UV light absorbance measurements in terms of a detergent amount. Through the concentration vs. absorbance curve developed, the absorbance values can then be converted into detergent concentrations in the tissues after they have been washed, thus indicating the rinsing effectiveness.
By improving the testing capabilities of manufacturers, CLC/TS 50677 contributes to increasing the efficiency of washing machines, making laundry less costly for users and more sustainable for the environment. For correctly separating colours, on the other hand, there is no standard that can help – at least for now!
CLC/TS 50677:2019 has been developed by CLC/TC 59X ‘Performance of household and similar electrical appliances’. Its Secretariat is currently held by DKE, the German Commission for Electrical, Electronic and Information Technologies of DIN and VDE.
For more information, please contact Mercedes Mira Costa